• When & Where: Seminars are generally (please, check the timeline and location before coming!) held on:
    • Wednesday afternoon at LINCS (14h-15h, Salle de Conseil) and
    • Thursday afternoon at Barrault (14h-15h, Amphi Saphir).
  • Contact us: if you wish to give a talk, please contact

[Next talks] All talks


08/07/2015Rahul Vaze (Tata Institute of Fundamental Research, Mumbai)Being Greedy is Good : Approximating the FDMA Capacity
01/07/2015Jeremie Leguay (Huawei)Online network optimization with SDN
01/07/2015Wong Wing Shing (Chinese University Hong Kong)Protocol Sequence based MAC for Multiple Packet Reception
25/06/2015Pedro Martinez-Julia (Univesity of Murcia)Identity based network architecture
24/06/2015Alexandre Reiffers-Masson (INRIA and LIA)Posting behavior in Social Networks and Content Active Filtering
24/06/2015I-Hong Hou (Texas A&M)Rethinking Competitive-Ratio: Two Case Studies
17/06/2015Tony Quek (SUTD, Singapore)Small Cells for 5G: Fundamentals and Recent Theory
17/06/2015I-Hong Hou (Texas A&M)The Capacity of Wireless Networks for Emerging Applications
10/06/2015Emilie Kaufmann (INRIA)A novel spectral algorithm for the identification of overlapping communities
03/06/2015Shahrokh Valaee (University of Toronto)Compressive Sensing, Opportunistic Network Coding and Repetition MAC for Connected Cars
03/06/2015Eitan Altman (INRIA)Timelines Analysis and competition over popularity, influence and visibility in social networks.
27/05/2015Nidhi HegdeLearning WiFi Performance (Alcatel-Lucent Bell Labs)
27/05/2015Don TowsleySampling Node Pairs in Large Graphs (Univ. of Massachusetts, Amherst)
22/05/2015Longbo Huang (Tsinghua University)The Power of Online Learning in Stochastic Network Optimization
20/05/2015Ramesh Sitaraman (UMass, Amherst and Akamai Technology)Understanding Online Video Users: A Key to the Future of the Internet
15/04/2015Luis Alvarez Corrales (Telecom ParisTech)Analyzing Interference from Static Cellular Cooperation using the Nearest Neighbour Model
15/04/2015Yu-Ting Lin (Telecom ParisTech/Orange)A Flow-Level Performance Model for Mobile Networks Carrying Adaptive Streaming Traffic
09/04/2015Janos Korner (U. La Sapienza)Entropies and capacity of graphs
08/04/2015Prof. Kenneth W. Shum (Institute of Network Coding)BASIC regenerating codes for distributed storage systems
01/04/2015Anastasios Giovanidis (Telecom ParisTech)Optimal Geographic Caching in Cellular Networks
25/03/2015Guillaume Baudart (ENS)A Synchronous View of Loosely Time-Triggered Architectures
18/03/2015Mario Gerla (UCLA)VANET Services and Mobile Vehicle Clouds
11/03/2015Udo Krieger (Otto-Friedrich-University Bamberg)On the Design of Integrated Forwarding andCaching Policies in Named-Data Networking
11/03/2015Patrick Loiseau (EURECOM)Game-theoretic statistics: Learning from data generated by strategic agents
04/03/2015Mostafa Ammar (Georgia Tech)The Cirrus Cloud Project: Opportunistic Mobile Cloud Computing
25/02/2015Fabian Suchanek (Telecom ParisTech)A Hitchhiker's guide to ontology
18/02/2015Claudia Malvenuto (Università  di Roma La Sapienza)Quasi-symmetric functions, poset partitions and finite topologies, part II: the combinatorial aspects
11/02/2015Christelle Rovetta (INRIA)Perfect sampling for closed queueing networks
11/02/2015The Dang Huynh (Alcatel-Lucent)Exploiting User Movement for Position Detection
04/02/2015Gyorgy Dan (KTH)Optimal content prefetching for cloud assisted content delivery
21/01/2015Peter Marbach (University of Toronto)A New Perspective on Distributed Scheduling in Wireless Multihop Networks
15/01/2015Hossein Vahabi Puya (Yahoo Labs)Social Recommender Systems
14/01/2015Yanlei Diao (Universityof Massachusetts, Amherst)Platforms and Applications for "Big and Fast" Data Analytics
08/01/2015Claudia Malvenuto (Università  di Roma La Sapienza)Quasi-symmetric functions, poset partitions and finite topologies
07/01/2015Amal Abdel-Razzak (UPMC)Cooperation between LTE and emergent DVB technologies for an efficient delivery of mobile TV


17/12/2014Victor Bahl (Microsoft Research)Cloud 2020: The Emergence of Micro Datacenter for Mobile Computing
10/12/2014Marco Mellia (Politecnico di Torino)Is there a case for mobile phone content pre-staging
03/12/2014Raluca Maria Indre (Orange)Evaluating user-perceived performance in FTTH access networks
19/11/2014Bruno Kauffmann (Orange)Catalog Dynamics: Impact of Content Publishing and Perishing on the Performance of a LRU Cache
12/11/2014Luca De Cicco (Politecnico di Bari)Controlling Adaptive Video Streaming Systems: One Knob is Enough
05/11/2014Richard Combes (Suplec)Unimodal Bandits without Smoothness
30/10/2014Jeremy Pitt (Imperial College London)Formal Models of Social Processes: Computational Justice for Fair and SustainableResource Allocation in Socio-Technical Systems.
29/10/2014Paola Bermolen and Federico Larroca (Universidad de la Republica, Montevideo)On the spatial reuse on large random wireless networks
22/10/2014Anais Vergne (Telecom ParisTech)Simplicial homology and wireless networks
15/10/2014Leonardo Linguaglossa (Alcatel Lucent Bell Labs)Caesar: a content router for high-speed forwarding on content names.
10/10/2014Fabien Gandon (INRIA)Bridging formal semantics and social semantics on the Web
08/10/2014Filippo Rebecchi (LIP6-UPMC/Thales)DROiD: Adapting to Individual Mobility Pays Off in Mobile Data Offloading
08/10/2014Claudio Imbrenda (Telecom ParisTech/Orange)Analyzing Cacheable Traffic in ISP Access Networks for Micro CDN Applications via Content-Centric Networking
18/09/2014Anne Etien (LIFL/Equipe projet INRIA Rmod)Maintenance et Evolution des logiciels
17/09/2014Emilio Leonardi (Politecnico di Torino)A unified approach to the performanceanalysis of caching systems
10/09/2014Cheng Wang (Pennsylvania State University)Energy management of demand in the cloud
16/07/2014Sameh Benfredj (Telecom ParisTech/Alcatel Lucent Bell Labs)Semantic-based IoT service discovery mechanism for dynamic environments
09/07/2014Olivier Marce (Alcatel Lucent Bell Labs)Tout ce que vous aimerez avoir su sur la 5G quand elle existera
04/07/2014Prof. Dr.-Ing. C. M�ller-SchloerOrganic Computing: Adaptivity and Self-organization at Runtime
02/07/2014Arvind Krishnamurthy (University of Washington)Approximately Synchronous Distributed Systems
25/06/2014Don Towsely (University of Massachusetts, Amherst)Randomness, Everlasting Security, and Undetectability
25/06/2014Lixia Zhang (UCLA)The art of packet format design
20/06/2014Nicolas RicheWhere People Look
19/06/2014George Iosifidis (CERTH/ITI and University of Thessaly)Incentive Mechanisms for User-provided Networks
18/06/2014Miodrag Jovanovic (INRIA/Orange)How user throughput depends on the traffic demand in large cellular networks
11/06/2014Sergey Foss (Heriot-Watt University, Edinburgh and Institute of Mathematics, Novosibirsk)Adaptive transmission protocols for a random multiple access channel
11/06/2014Dr. Beth Coleman (University of Waterloo, Ontario Canada) and Howard Goldkrand (SapientNitro)Smart Cites, Smart things...and Smart Citizens: designing the city as platform
11/06/2014Venkat Anantharam (University of California, Berkeley)Convex relative entropy decay in Markov chains
14/05/2014Thomas Bonald (Telecom ParisTech)Application of queuing theory to traffic engineering
07/05/2014Izhak Rubin (UCLA)Relay aided Communications Networking for Power Line and Vehicular System
30/04/2014Uri Yechiali (Tel-Aviv University)Tandem Jackson Networks, Asymmetric Inclusion Processes and Catalan Numbers
23/04/2014DaeYoung Kim (CNU)Some Thoughts on Loc/ID Separation
10/04/2014Janos Korner (U. la Sapienza)From Shannon to Infinity
09/04/2014Petr Kuznetsov (Telecom ParisTech)The Case for Reliable Software Transactional Networking
08/04/2014Patricio Reyes (Universidad Carlos III de Madrid)Towards Detecting Influential Individuals in Social Networks
02/04/2014Stephane Wustner (Technicolor)Characterizing bufferbloat from end-hosts
02/04/2014Giuseppe Scavo (Alcatel Lucent Bell Labs and INRIA)Gold mining in a River of Internet Content Traffic
26/03/2014Salaheddine Elayoubi (Orange)Making mobile access networks green: from research to standardization
20/03/2014Zaheer Khan (University of Oulu, Finland)Opportunistic Channel Selection by Cognitive Radios Under Imperfect Observations and Limited Memory: A Repeated Game Model
19/03/2014Adel Sohbi (Telecom ParisTech)Quantum Information
12/03/2014Yves Vanaubel (Universite' de Liege)Network Fingerprinting: TTL-Based Router Signatures
05/03/2014Remi Varloot (ENS)On the resiliency of the French Internet
26/02/2014Karel De Vogeleer (Telecom ParisTech)Energy-Aware Computing with Application Processors
26/02/2014Nihel Djoher Benzaoui (Alcatel-Lucent)Impact of the electronic architecture of optical slot switching nodes on latency in ring networks
19/02/2014Steve Uhlig (Queen Mary University, London)Optimal cache allocation for content-centric networking
05/02/2014James Roberts (IRT-SystemX)Be fair to flows: a fair network is attractive and trustworthy and far more than just adequate
29/01/2014Jim Kurose (University of Massachusetts Amherst)Protecting Privacy While Providing Utility in Published Network Mobility Traces Using Differential Privacy
22/01/2014Michele Tortelli (Politecnico di Bari)COBRA: Lean Intra-domain Routing in NDN
15/01/2014Laurent Massouli� (INRIA and Microsoft Research)Community detection in stochastic block models via spectral methods
08/01/2014Brigitte Cardinael (Orange)Presentation du PPP 5G


11/12/2013Vern Paxon (UC Berkeley and ICSI)Combating Internet Attacks Via Infiltration
04/12/2013Luca De Cicco (Politecnico di Bari)Understanding the Dynamic Behaviour of the Google Congestion Control
27/11/2013Nanette S. Levinson (American University Washington DC)Adaptive Internet Governance: Innovation in the Ecosystem
26/11/2013Sean Meyn (University of Florida)Feature Selection for Neuro-Dynamic Programming
13/11/2013Oana Goga (LIP6/UPMC)Reliable and Scalable Account Correlation Across Large Social Networks
06/11/2013Hugues Fauconnier et Carole DelporteDtecteurs de dfaillances
23/10/2013Sebastien Faye (Telecom ParisTech)LINCS PhD seminar - Adaptive traffic light control using a wireless sensor network
15/10/2013Ravi R. Mazumdar (University of Waterloo)Randomized Load Balancing in Large Processor Sharing Systems
09/10/2013Jordi Domingo-Pascual (Universitat Politecnica de Catalunya)Locator/ID split: Analysis of the caching system
18/09/2013Alexandre Maurer (LIP6/UPMC)Tolerating Byzantine failures in sparse networks
18/09/2013Riad Mazloum (LIP6/UPMC)Violation of interdomain routing assumptions
04/09/2013Dohy Hong and Alonso Silva (Alcatel Lucent Bell Labs)Game theory based economical model of large graph exploitation: illustration for the churn management.
28/08/2013Sarthak GroverPeeking Behind the NAT: An Empirical Study of Home Networks
17/07/2013Marceau Coupechoux (Telecom ParisTech)POMDP Approach for Pilot Allocation and Receive Antenna Selection
10/07/2013Luigi Iannone (Telecom ParisTech)Toward an Enhanced Internet Architecture: the Locator/Identifier Separation Protocol (LISP)
03/07/2013Thomas Bourgeau (LIP6/UPMC)Efficient IP-level network topology capture
03/07/2013Remi Leone (Thales TAI/Telecom ParisTech)Optimizing QoS in Wireless Sensor Networks Using a Caching Platform
26/06/2013Jacques Sakarovitch (CNRS - Telecom ParisTech)The validity of weighted automata
19/06/2013Venkat Anantharam (University of California, Berkeley)Nash equilibrium structure of a class of blocking games arising in network security
19/06/2013Chi Wan Sung (City University of Hong Kong)Sparse Network Code for Wireless Broadcast
12/06/2013Michal Pioro (Lunds Universitet)Integer programming models for transmission scheduling in wireless networks.
07/06/2013Thomas Hujsa, LIP6/UPMCPolynomial Sufficient Conditions of Well-Behavedness for Weighted Join-Free and Choice-Free System
07/06/2013Petr KuznetsovWait-Freedom with Advice
05/06/2013~4 LINCS PhDsLINCS PhD seminar
04/06/2013J�r�mie Jakubowicz (T�l�com SudParis)From Gossip to Distributed Optimization (and back again)
29/05/2013Marco Mellia (Politecnico di Torino)Internet traffic monitoring: Discerning Content and Services in a Tangled Web
22/05/2013Tracy Camp (Colorado School of Mines)SMOOTH: A Simple and Realistic Way to Model Human Mobility
14/05/2013Brigitte Jaumard (Concordia University)Design of a Survivable VPN Topology over aService Provider Network
03/05/2013Uichin Lee (KAIST)CLIPS: Infrastructure-free Collaborative Indoor Positioning Scheme for Time-critical Team Operation
30/04/2013Sean Meyn (Univ. of Florida)Control of the grid in 2020, and how economics can help us.
26/04/2013Katrin Wolf (TU Berlin)Microinteractions: Finger mounted sonsors for ubiquitous and busy-hand interfaces
25/04/2013Mounia Ziat (Northern Michigan University)InGrid: Interactive Grid Table
24/04/2013Annie Gentes (Telecom ParisTech) and Ted Selker (Carnegie Mellon Silicon Valley)Social Science Meets Design Activities in Considerate Systems
24/04/2013Daniela TuloneReal-time Monitoring of Physical Phenomena and their Dynamics with Quality Guarantees via Wireless Sensor Networks
23/04/2013Longbo Huang, (Tsinghua University)A Benes Packet Network
17/04/2013Johanna Mathieu (ETH)Controlling Electric Loads to Manage Energy Imbalances in Power Systems
15/04/2013Lixia Zhang (UCLA)NDN Reaching 3: Results and Challenges -- a personal perspective
10/04/2013Izhak Rubin (UCLA)Robust Mobile Wireless Networking
03/04/2013The Dang Huynh (Alcatel-Lucent)Analyzing methods solving system of linear equations in PageRank context
03/04/2013Yixi Gong (Telecom ParisTech)Fighting the bufferbloat: on the coexistence of AQM and low priority congestion control
03/04/2013Mathieu Leconte (Technicolor - INRIA)Load balancing in distributed content distribution networks
03/04/2013Tiphaine Phe-Neau (UPMC Sorbonne Universites)The Strength of Vicinity Annexation in Opportunistic Networking
03/04/2013~4 LINCS PhDsLINCS PhD seminar
29/03/2013Yezekael Hayel (Universit� d'Avignon)Optimization of Decentralized Partially Observable Systems in Cognitive Radio Networks
27/03/2013 Inauguration of the Doctorate School, EIT ICT Labs
20/03/2013Paul Keeler, INRIA/ENSCapturing the SINR in cellular networks with Poisson processes
14/03/2013Petr KuznetsovOn the Benefits of Being Optimistic and Relaxed
13/03/2013Masha Frolkova (CWI, Amsterdam)Fluid limit approximations of bandwidth-sharing networks with rate constraints
06/03/2013Giovanni Pau (LIP6)V-NDN: Vehicular Named Data
27/02/2013Diego Perino (Alcatel Lucent Bell Labs)On the design of architectures and algorithms to support content-oriented functionalities in high speed network equipments.
13/02/2013Marc Lelarge (INRIA)Universality and Phase Transition in Compressed Sensing.
06/02/2013Simon Perreault (Viagenie)IPv6 Migration and Carrier-Grade NAT (CGN)
30/01/2013Isabel Amigo (Telecom Bretagne)A Pricing Mechanism and Revenue Sharing in Network Service Providers Alliances
16/01/2013M. Feuillet, F. Contat, G. Valadon (ANSSI)French Internet resilience


19/12/2012Marc Crovella (Boston University)Better routing with hyperbolic geometry
05/12/2012Admela Jukan (Technische Universitat Braunschweig)Next Steps towards IP-optical Service Convergence: A Network Management Perspective
28/11/2012Alexander Pelov (Telecom Bretagne)A network-centric point of view on Smart Grids
21/11/2012Alexandre Proutiere (KTH and INRIA)Iterative Power Packing for Distributed Multiple Access in Wireless Networks
14/11/2012Alonso Silva (Alcatel Lucent Bell Labs)Auctions of Licensed vs Unlicensed Use of Spectrum
24/10/2012Mohan DhawanA Browser-based Network Measurement Platform
17/10/2012George Kesidis (Pennsylvania State University)Sequential Anomaly Detection in a Batch with Growing Number of Tests: Application to Network Intrusion Detection
10/10/2012Philippe Jacquet (Alcatel Lucent Bell Labs)Joint complexity of short texts or how to spy Twitter
03/10/2012Anastasios Giovanidis (INRIA)How much do we benefit from cooperation between pairs of neighbouring base stations
28/09/2012Tova Milo (Université de Tel Aviv)Making Collective Wisdom Wiser
19/09/2012Franois Durand (LINCS / Inria)Towards less Manipulable Voting Systems
12/09/2012Siu-Wai Ho (University of South Australia)Error Free Perfect Secrecy Systems
10/09/2012Lixia Zhang (UCLA)Evolving Internet into the Future via Named Data Networking
05/09/2012Wojciech Szpankowski (Purdue University)NSF Center for Science of Information: An Overview
24/07/2012Ian F. Akyildiz (Georgia Institute of Technology)Nanonetworks: A New Frontier in Communication
20/07/2012Dave TathControlling Queue Delay
18/07/2012Yoram Haddad (Jerusalem College of Technology and Ben-Gurion University)SINR Diagram and their application to Interference Cancellation
11/07/2012manypostoponed to september!! --ACM SIGCOMM Information Centric Networking (ICN) preview talks--
10/07/2012Fr'ed'eric Cuppens et Nora Cuppens-Boulahia (T'el'ecom Bretagne)Expression, D'eploiement, Analyse et Administration de Politiques de S'ecurit'e
04/07/2012Luigi Rizzo (Univ. of Pisa)netmap: a novel framework for fast packet I/O
28/06/2012Prof. Ashwin Gumaste (IIT Bombay)Design, development and deployment of a Ultra-Fast Low-Latency Carrier Ethernet Switch Router
26/06/2012Pr. David A. Rosenbaum (Penn State University)Cognition and Action (Joint ACM SiGCHI Paris - INFRES seminar)
08/06/2012FranÁois TaÔani (Lancaster Univ.)Modular Georecommendation In Gossip-Based Social Networks
06/06/2012Mathieu LeconteBipartite Graph Structures for Efficient Balancing of Heterogeneous Loads
31/05/2012Dr Raphael Frank (University of Luxembourg)Improving Highway Traffic through Partial Velocity Synchronization
30/05/2012Alexandre Menai (Akamai)Mobile Web AccelerationChallenges
16/05/2012Davide CudaDistributed Scheduling Algorithm for Asynchronous Input-Queued Switches
09/05/2012Dohy Hong (ALU Bell Labs)D-iteration: Asynchronous Distributed Computation
03/05/2012Ken ChristensenGreen Networks: Substituting, Consolidation and Scheduling to Save Energy
02/05/2012Chandramani Singh (IISc Bangalore)Game-theoretic resource management in cellular networks
25/04/2012Vincent ToubianaPrivacy preference expression
18/04/2012Pedro Maria Santiago del RioWire-speed statistical classification of network traffic on commodify hardware
11/04/2012R-M. IndreTowards All-Optical Packet Networks Using Optical Switch-Combiners
04/04/2012Timothy G. Griffin (University of Cambridge)Routing in Equilibrium
28/03/2012Giacomo MorabitoOpportunities and challenges for ICN experimentation and deployment inSoftware Defined Networks
21/03/2012Manjesh Kumar Hanwal, Diana Joumblatt, Massimo Gallo, Giuseppe Rossini, Natalya RozhnovaINFOCOM preview talks
21/03/2012Manjesh Kumar HanwalStochastic Geometry based Medium Access Games
21/03/2012Natalya RozhnovaAn effective hop-by-hop Interest shaping mechanism for CCN communications
21/03/2012Giuseppe RossiniOn sizing CCN content stores by exploiting topological information
21/03/2012Massimo GalloICP: Design and Evaluation of an Interest Control Protocol for Content-Centric Networking
21/03/2012Diana JoumblattCharacterizing end-host application performance across multiple networking environments
21/03/2012Tien Viet NuyenOn the Spatial Modeling of Wireless Networks byRandom Packing Models
20/03/2012Mark Crovella (Boston University)A Fine-Grained Distance Metric for Analyzing Internet Topology
14/03/2012Dohy HongD-iteration method or how to improve Gauss-Seidel method
07/03/2012Jordan AugeMeasurement-Based Admission Control for Flow-Aware Implicit Service Differentiation
29/02/2012Lucas DiCioccio, Oana Goga, Ahlem Reggani, Claudio TestaPAM Preview talks
29/02/2012Ahlem RegganiAn End-Host View on Local Traffic at Home and Work
29/02/2012Claudio TestaExperimental Assessment of BitTorrent Completion Time in Heterogeneous TCP/uTP swarms
29/02/2012Oana GogaSpeed Measurements of Residential Internet Access
29/02/2012Lucas DiCioccioProbe and Pray: Using UPnP for Home Network Measurements
22/02/2012Calvin Chun Shue Chen (Alcatel Lucent)Self-Optimization of Radio Resources in Small and Macro Cell Networks
15/02/2012Jim Kurose (University of Massachusetts, Ahmerst)Design and Analysis of Content Caching Networks
09/02/2012Bogdan Cautis (Telecom ParisTech)Top-k Search in Social Tagging Systems
08/02/2012Miguel Elias Mitre Campista (Universidade Federal do Rio de Janeiro, UFRJ)VNEXT: Virtual NEtwork management for Xen-based Testbeds
01/02/2012Giovanna Carofiglio (Alcatel Lucent)Modeling Data Transfer in Content-Centric Networks
26/01/2012Laurent Georges (INRIA Roquencourt)Robustesse temporelle dans les systËmes embarquÈs mono et multiprocesseur
25/01/2012M. JonkheereThe Fleming Viot process driven by subcritical branching: a selection principle.
18/01/2012Kim Son NGUYEN (Internship ALU/LINCS)PageRank extension and a new way to measure scientific impact


15/12/2011Aldric Degorre (LIAFA)Volume and Entropy of Timed Regular Languages
07/12/2011Fabien Mathieu (INRIA/ENS)Performance of P2P Networks with Spatial Interactions of Peers
30/11/2011Konstantinos Katsaros (Athens University of Economics and Business)Future Internet: An information-centric perspective
16/11/2011Francois Durand (Alcatel Lucent Bell Labs/INRIA)Manipulability of Voting Systems
02/11/2011Antonio Kung (Trialog, CTO)Practicing Interoperability: Technical and Scientific Challenge
21/10/2011Micheal Ment (Univ. of Tbingen)Resilient Networking and Resource Management in IP Networks
19/10/2011Dave TahtBufferbloat
29/09/2011Catherine Rosenberg (University of Waterloo)How can the Internet help smarten the grid
05/08/2011S. Felix Wu, UC DavisOn Leveraging Social Informatics for Cyber Security
30/06/2011M. Gagnaire, joint work with E. Doumith and S. Al ZahrMutual Impact of Traffic Correlation and Regenerator Concentration in Translucent WDM Networks
30/06/2011M. ZukermanModeling and blocking probability evaluation for multi-priority circuit switched optical networks
23/06/2011Venkat Anantharam (UC Berkeley)Anonymity over Networks
15/06/2011XVII Forum IFSTTAR, Gestion de la Relation Client & Transport
19/05/2011Pierre LatoucheModles de graphe alatoire classes chevauchantes pour l'analyse des rseaux
19/05/2011Philippe GambetteProblmes d'optimisation combinatoire pour la reconstruction de rseauxphylogntiques
12/05/2011Anthony LeverrierGraphes de secrets
12/05/2011David AugerComment jouer dans l'incertain : thorie et pratique
05/05/2011Alain Couvreur?
05/05/2011Bertrand MeyerConstructions et bornes pour les codes tmoin
28/04/2011Eleonora GuerriniDes idaux de polynmes pour les codes systmatiques
28/04/2011Sorina IonicaCouplages et volcans d'isognies
21/04/2011Brice MayagMACBETH 2-additif: une nouvelle mthode interactive d'aide la dcision
21/04/2011David DurisAcyclicit des hypergraphes et applications
14/04/2011Makhlouf HadjiOptimisation des rseaux composantes unicycliques : approche polydrale
14/04/2011Christophe MoutonVisualisation scientifique interactive et collaborative
14/04/2011Nizar MessaiAnalyse de Concepts Formels par Similarit : Fondements et Applications
07/04/2011Franois DelbotComparaison et valuation en moyenne d'algorithmes d'approximation pourle problme du vertex cover
07/04/2011Sonia ToubalineProblmatiques de scurit ou de fiabilit pour certains problmes de graphes
31/03/2011Rodney Van Meter (Keio University)Recursive Quantum Repeater Networks
24/03/2011Anastasia Bezerianos (Centrale)User-centered designed visualization and analysis of graphs
17/03/2011Pascal Moyal (Univ. Tech. Compigne)Limite en grand graphe pour une pidmie SIR sur un rseau alatoire
10/03/2011Alexis Polti et Samuel TardieuExperience de pedagogie active en cycle master
04/03/2011Dah Ming Chiu (Chinese University of Hong Kong, CUHK)Models and replication algorithms for P2P-assisted VoD
24/02/2011Gerard Cohen (Telecom ParisTech)Quelques applications des codes correcteurs
10/02/2011Jean-Louis Dessalles (Telecom ParisTech)Pourquoi donner des informations aux autres
10/02/2011Alexandre Brandwajn (University of California at Santa Cruz)Seeking simplicity in complex systems
20/01/2011Paul Amer (University of Delaware)Reliable Transport Layer Protocols Should Not Be Allowed To Renege
13/01/2011Elham Kashefi (University of Edinburgh)Verification of Quantum Mechanics


16/12/2010Jean-Louis Rougier (Telecom ParisTech)Energy-Aware Routing: a Reality Check
09/12/2010Subhabrata Sen (AT&T Labs)Network Management from an ISP perspective: Keeping up with the times
07/12/2010ICSSEA22nd International Conference on Software & Systems Engineering and their Applications
07/12/2010Milind Madhav Buddhikot (Alcatel Lucent)Red, White and Green: Colors of the New Cellular Revolution
03/12/2010Marco Ajmone MarsanEnergy Efficient Wireless Internet Accesswith Cooperative Cellular Networks
02/12/2010Dario RossiA tutorial on Green Networking
02/12/2010MFDLMthodes Formelles dans le Dveloppement Logicie
30/11/2010Julie mac CannAutonomic Computing on WSN (A Brief Story of time)
18/11/2010Pierre Senellart (Tlcom ParisTech)Probabilistic XML Data Management
11/10/2010Mark Karpovsky (Reliable Computing Lab., Boston Univ.)Design of Secure Hardware Resistant to the Attacks
29/09/2010Chairs Maurice Gagnaire and Prof. Naoaki YamanakaThe First TELECOM ParisTech -- Keio University Joint Workshop on Future Networking
09/09/2010Simon Litsyn (EE-Systems, Tel Aviv University)A la recherche du temps et de la position perdus
15/07/2010Lavy Libman, University of SydneyTowards Optimal Forwarding in Wireless Networks: Opportunistic Routing Meets Network Coding
08/07/2010Joseph Boutros (TAMUQ)Construction de rseaux euclidiens par l'inverse de leur matricegnratrice
05/07/2010Oleg Sokolsky (U. Penn.)A Process Algebraic Framework for Modeling Resource Demand and Supply
01/07/2010Laurent DecreusefondFinance for dummies
16/06/20106eme journe Optimisation des rseaux6eme journe Optimisation des rseaux, organise conjointement par Tlcom ParisTech et le groupe Optimisation les rseaux (GT du GdR RO et de la ROADEF)
10/06/2010Igor ShparlinskiOn Pairing Friendly Elliptic Curves and Fields
03/06/2010Elie NajmService Orchestration with Orcharts and Typecharts
27/05/2010Michel Kieffer (Universit Paris-Sud et Telecom ParisTech)Joint Protocol-Channel Decoding
26/05/2010Mario Gerla, UCLAPipeline Network Coding for Multicast Streams
20/05/2010Jean-Louis DessallesLa thorie de la simplicit - Application la probabilit subjective et la pertinence des vnements.
06/05/2010Eduardo Ferraz (Telecom ParisTech)Algebraic topology applied to random sensor networks
06/05/2010Murad S. Taqqu (Boston University)Self-similarity and computer network traffic
15/04/2010Nouha Oualha (Telecom ParisTech)Scurit et coopration pour le stockage de donnes pair--pair
08/04/2010Ada Diaconescu (Telecom ParisTech) + Sylvain Frey (ImperialCollege, London)Conflict Resolution as an Autonomic Computing Paradigm
02/04/2010CCASminaire Codage, Cryptologie, Algorithmes (CCA)
01/04/2010C. Testa and S. Valenti (Telecom ParisTech)News from the Internet congestion control world
25/03/2010XV FORUM NTIC: SeriousGamesJeux srieux, ralit virtuelle et ralit augmente
18/03/2010Alain Couvreur (INRIA)Codes gomtriques
11/03/2010P. Rigaux (LAMSADE, Universit Paris Dauphine)Nouvelles techniques de stockage, d'indexation et detraitement de donnes massives.
11/03/2010K. Chine (Cloud Era Ltd)Cloud Computing, logiciel libre et science ouverte,vers une plateforme universelle pour le calcul scientifique et statistique.
11/03/2010X. Grehant (Tlcom ParisTech)Allocation de ressources en grilles de calcul et clouds
25/02/2010Romain Allaume (Telecom ParisTech et co-fondateur de lastart-up SeQureNet)Cryptographie et Information Quantique
18/02/2010Thomas Bonald (Tlcom ParisTech)Is congestion control critical for the future Internet
11/02/2010Michal Aupetit and Sylvain Lespinats (CEA, LIST "Laboratoire Intelligence Multi-capteurs et Apprentissage")La visualisation multidimensionnelle pour l'analyse exploratoire de donnes
04/02/2010Cline Chevalier (Tlcom ParisTech)Cryptographie distribue base de mots de passe
28/01/2010Yves Guiard (CNRS & Tlcom ParisTech)Sur le lien entre la vitesse et l'imprecision de nos mouvements et sur le rle du facteur d'chelle
21/01/2010Philippe Godlewski et Azin Arya (Tlcom ParisTech & SFR)"Radio fingerprinting" for localization of mobile terminals
21/01/2010Philippe Godlewski et Rodrigo Soul de Castro (Tlcom ParisTech)Canaux radio cognitifs en diffusion et en contrle MAC pour l'accs dynamique au spectre (DSA)


17/12/2009Grard Memmi (Tlcom ParisTech)Sur un problme de couplage
10/12/2009Maximilien Gadouleau (Univ. Reims)Codes algbriques pour le codage rseau alatoire
03/12/2009Marco Cagnazzo (Tlcom ParisTech)Compression for the Network: Scalable and Multiple Description Coding
26/11/2009Dario Rossi (INFRES Telecom Paristech)P2P-TV: State of Art and Application Analysis via Sherlock
12/11/2009Claude ChaudetQuelques pistes pour accrotre la dure de vie d'un rseau de capteurs
12/11/2009Michel Marot (Telecom SudParis)Quelques lments pour contribuer la problmatique du routage dans les rseaux de capteurs.
29/10/2009Jnos Krner (Univ. Rome 1 "La Sapienza")Structures of diversity
22/10/2009Aruna Jayasuriya (ITR, Univ. South Australia, Adelaide)Supporting QoS for Realtime Applications in Wireless Infrastructure Networks
15/10/2009Jacques Sakarovitch (CNRS & Tlcom ParisTech)A propos des automates avec multiplicit, sur les langages rationnels de mme fonction gnratrice
24/07/2009Pr. Erol Gelenbe, Imperial College LondonSteps toward self-aware networks
28/05/2009Minh Anh Tran, PostDoc at ENSTThorie des jeux pour la modlisation des terminaux mobiles multi-homs
16/04/2009Guillaume Valadon, PhDMesure et analyse des reseaux
12/02/2009Pr. Marceau Coupechoux, ENSTAnalytical Evaluation of Various Frequency Reuse Schemes in OFDMA Networks
29/01/2009Pr. Pascal Urien, TELECOM ParisTech, founder of EtherTrustDes cartes puce pour l'Internet: "Are you serious". Petite histoire d'EtherTrust, spin-off de Tlcom ParisTech.


08/12/2008Pr. Dario Rossi, Telecom ParisTechStochastic Packet Inspection for Automated Traffic Classification
03/11/2008Pr. Tamer BASAR, University of Illinois at Urbana-ChampaignOptimum Active Pricing for Communication Networks
03/11/2008Pr. Jean-Pierre HUBAUX, Ecole Polytechnique de Lausanne (EPFL)Game Theory and Wireless Security


Date:08/07/2015, 14h
Room:LINCS, Salle du Conseil
Speaker:Rahul Vaze (Tata Institute of Fundamental Research, Mumbai)
Talk:Being Greedy is Good : Approximating the FDMA Capacity
Abstract:We consider the classical problem of approximating the FDMA capacity,where the problem is to allocate disjoint resources (frequencies) tomultiple users so as to maximize the sum-utility (data rate). Manyheuristic approaches, such as convex relaxation etc,. are known to solvefor the FDMA capacity, however, fail to give any theoretical guarantees.We approach this problem via results on greedy algorithms for sub-modularfunctions. The main result is to show that the capacity of parallelGaussian channels is a sub-modular function. Following this result, we geta 2-approximation (which is at least 1/2 times equal) to the optimalFDMA capacity.
Biography:Rahul Vaze received his Ph.D. from The University of Texas at Austin in 2009. SinceOct. 2009 he is a Reader at the School of Technology and ComputerScience, Tata Institute of Fundamental Research, Mumbai, India. Hisresearch interest are in multiple antenna communication, ad hoc networks,combinatorial resource allocation. He is a co-recipient of the Eurasipbest paper award for year 2010 for the Journal of Wireless Communicationand Networking, and recipient of Indian National Science Academy's youngscientist award for the year 2013 and Indian National Academy ofEngineering's young engineer award for the year 2013.
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Date:01/07/2015, 14h
Room:LINCS, Salle du Conseil
Speaker:Jeremie Leguay (Huawei)
Talk:Online network optimization with SDN
Abstract:Software-Defined Networking (SDN) is an emerging network architecture decoupling the network control and forwarding functions, and it enables the network elements to become directly programmable and the underlying infrastructure to be abstracted for applications and network services. SDN is ideal for the bandwidth hungry and dynamic nature of today's applications, since it permits through a logically centralized controller to reconfigure instantaneously the network, thus exploiting the network capacity more efficiently than distributed routing protocols. Looking at classical networking problems through the angle of centralization brings very challenging and new online network optimization problems. These problems were not considered when everything was done at network planning phase with no hard time constraints. This talk gives an introduction to this new domain and presents a few contributions on fast connection setup and network re-optimization.
Biography:Dr. Jrmie Leguay received his a Ph.D. degree from Pierre & Marie Curie University in Paris on ad hoc and delay tolerant networks. He was awarded the Thales Ph.D Prize for this work in 2007. From 2007 to 2009, he worked as a Research Engineer at Thales Communications and extended his research activities to vehicular and wireless sensor networks. From 2009 to 2014, he was responsible for the Research & Technology lab on networked systems at Thales Communications & Security where he especially developed activities on mobile wireless networks and software-defined networks. He joined Huaweis French research Center in November 2014 to lead the traffic and network optimization team. His current research interests are protocol design and network optimization for fix and mobile environments.
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Date:01/07/2015, 11h
Room:LINCS, Salle du Conseil
Speaker:Wong Wing Shing (Chinese University Hong Kong)
Talk:Protocol Sequence based MAC for Multiple Packet Reception
Abstract:Massey and Mathys proposed protocol sequences as a new design approach to media access control protocol without feedback that delivers throughput performance that can asymptotically converge to systems with feedback. In this talk, we present recent research results on protocol sequences that have potential application to future wireless networks. These protocol sequence results relate to multiple-packet reception networks, frequency hoping and successive interference cancellation MIMO systems.
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Date:25/06/2015, 14h
Room:LINCS, Salle du Conseil
Speaker:Pedro Martinez-Julia (Univesity of Murcia)
Talk:Identity based network architecture
Abstract:The Internet is evolving from a static, host-based, network to a dynamic infrastructure of interconnected objects of many kinds. This requires a redefined network model and a new architecture that is able to evolve and cope with new requirements without adding complexity to the endpoints. This presentation shows the summary of the research carried out to face such challenges. We introduce the concept of "network object", which is then used as communication endpoint. Moreover, we outline the necessary components to support the transition of the Internet to the new network model.
Biography:Pedro Martinez-Julia received the B.S. degree in Computer Science from the Open University of Catalonia in 2009 and the M.S. degree in Advanced Information Technology and Telematics from the University of Murcia in 2010. Since 2009 he is a research fellow and Ph.D. candidate in the Department of Communication and Information Engineering at the University of Murcia. He has led and has been part of the research staff of many tasks within the GEANT project (GN3/GN4) and collaborated with other EU projects. His main interests are the architecture for the Future Internet, overlay networks, and the distributed systems and services.
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Date:24/06/2015, 14h
Room:LINCS, Salle du Conseil
Speaker:Alexandre Reiffers-Masson (INRIA and LIA)
Talk:Posting behavior in Social Networks and Content Active Filtering
Abstract:In this talk, first we describe a model of the posting behavior in Social Networks in topics which have negative externalities, and the second objective of it is to provide a content active filtering control such that the content diversity increase. By negative externalities, we mean that when the quantity of posted contents about some topic increases the popularity of posted contents decreases. We introduce a dynamical model to describe the posting behavior of users taking into account these externalities. Our model is based on stochastic approximations and sufficient conditions are provided to ensure its convergence to a unique rest point. We provide a close form of this rest point. Content Active Filtering (CAF) are actions taken by the administrator of the Social Network in order to promote some objectives related to the quantity of contents posted in various topics. As objective of the CAF we shall consider maximizing the diversity of posted contents.
Biography:Alexandre Reiffers is a third year PHD student at INRIA and LIA. His supervisors are Eitan Altman and Yezekael Hayel. His current research interests include routing games, bi-level problem and differential games; all applied to Social Networks and Internet Economics.
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Date:24/06/2015, 11h
Room:LINCS, Salle du Conseil
Speaker:I-Hong Hou (Texas A&M)
Talk:Rethinking Competitive-Ratio: Two Case Studies
Abstract:Competitive ratio is traditionally defined by asking the question: How much service can a policy deliver with a fixed amount of resource. This definition requires applications to adapt to their perceived service. However, many emerging applications, such as multimedia and safety-critical applications, have strict service requirements. In order to accommodate these applications, we redefine competitive ratio by asking: How much resource does a policy need to provide a fixed degree of service. By studying two different applications, we demonstrate that answering the second question reveals some surprising results.
Biography:I-Hong Hou is an assistant professor in the ECE Department of the Texas A&M University. He received his Ph.D. from the Computer Science Department of the University of Illinois at Urbana-Champaign. His research interests include wireless networks, wireless sensor networks, and real-time systems. He received the C.W. Gear Outstanding Graduate Student Award from the University of Illinois at Urbana-Champaign, and the Silver Prize in the Asian Pacific Mathematics Olympiad.
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Date:17/06/2015, 14h
Room:LINCS, Salle du Conseil
Speaker:Tony Quek (SUTD, Singapore)
Talk:Small Cells for 5G: Fundamentals and Recent Theory
Abstract:With 4G cellular technologies now beginning to be deployed widely around the world, the fifth generation (5G) mobile and wireless communication technologies are emerging into research fields. New services, applications and devices will drive requirements on data rate, ubiquity of data services, latency, cost, and reliability and further drive data traffic growth. Networks, services, and devices will be more heterogeneous and the need to connect billions of devices to the network will emerge. To meet the above challenges, small cell networks will be crucial to meet the requirements in terms of spectral efficiency and energy efficiency. In this talk, we will discuss some of our recent work in small cell networks that can potentially help us to meet such challenges.
Biography:Tony Q.S. Quek received the B.E. and M.E. degrees in Electrical and Electronics Engineering from Tokyo Institute of Technology, Tokyo, Japan, respectively. At Massachusetts Institute of Technology (MIT), Cambridge, MA, he earned the Ph.D. in Electrical Engineering and Computer Science. Currently, he is an Assistant Professor with the Singapore University of Technology and Design (SUTD). He is also a Scientist with the Institute for Infocomm Research. His current research topics include sensor networks, heterogeneous networks, smart grid, green communications, wireless security, big data processing, compressed sensing, IoT, and cognitive radio.Dr. Quek has been actively involved in organizing and chairing sessions, and has served as a TPC member in a numerous international conferences. He served as the Co-Chair of the Communication Theory Symposium for IEEE ICC in 2015, the PHY & Fundamentals Track for IEEE WCNC in 2015, the PHY & Fundamentals Track for IEEE EuCNC in 2015, the Communications Track for IEEE ATC in 2015, and the Communication and Control Theory Symposium for IEEE ICCC in 2015. He is currently an Executive Editorial Committee Member for the IEEE Transactions on Wireless Communications, an Editor for the IEEE Transactions on Communications and the IEEE Wireless Communications Letters. He was Guest Editor for the IEEE Signal Processing Magazine (Special Issue on Signal Processing for the 5G Revolution) in November 2014 and the IEEE Wireless Communications Magazine (Special Issue on Heterogeneous Cloud Radio Access Networks) in June 2015.Dr. Quek received the 2008 Philip Yeo Prize for Outstanding Achievement in Research, the IEEE Globecom 2010 Best Paper Award, the 2011 CAS Fellowship for Young International Scientists, the 2012 IEEE William R. Bennett Prize, the IEEE SPAWC 2013 Best Student Paper Award, and the IEEE WCSP 2014 Best Paper Award.
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Date:17/06/2015, 11h
Room:LINCS, Salle du Conseil
Speaker:I-Hong Hou (Texas A&M)
Talk:The Capacity of Wireless Networks for Emerging Applications
Abstract:Future wireless traffic is going to be dominated by emerging applications such as VoIP, video conferencing, video/audio streaming, etc. These applications have their unique traffic patterns, performance metrics, and service requirements. Traditional network performance metrics, such as throughput, delay, and delay jitter, can no longer provide a precise characterization for these emerging applications. In this talk, we discuss two different kinds of emerging applications. We introduce an analytical framework to model these applications and practical characteristics of wireless channels. We derive the capacity regions of wireless networks for serving these applications, and develop tractable scheduling policies for achieving the capacity regions.
Biography:I-Hong Hou is an assistant professor in the ECE Department of the Texas A&M University. He received his Ph.D. from the Computer Science Department of the University of Illinois at Urbana-Champaign. His research interests include wireless networks, wireless sensor networks, and real-time systems. He received the C.W. Gear Outstanding Graduate Student Award from the University of Illinois at Urbana-Champaign, and the Silver Prize in the Asian Pacific Mathematics Olympiad.
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Date:10/06/2015, 14h
Room:LINCS, Salle du Conseil
Speaker:Emilie Kaufmann (INRIA)
Talk:A novel spectral algorithm for the identification of overlapping communities
Abstract:Spectral algorithms are popular methods for finding a partition of a network into groups of nodes that are densely connected, called communities. However, the structure of many real world networks is better explained by a set of overlapping communities than by a partition. In this talk, I will present combinatorial spectral clustering (CSC), a simple spectral algorithm designed to identify overlapping communities. The algorithm is motivated by a random graph model called stochastic blockmodel with overlap (SBMO), under which it is proved to be consistent. Joint work with Thomas Bonald and Marc Lelarge.
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Date:03/06/2015, 10h
Room:LINCS, Salle du Conseil
Speaker:Shahrokh Valaee (University of Toronto)
Talk:Compressive Sensing, Opportunistic Network Coding and Repetition MAC for Connected Cars
Abstract:Recently we are witnessing the emergence of situation-aware vehicles, equipped with plurality of sensors that can help driver with vehicle control and maneuvering. Cars that can park themselves, provide lane-departure warning, and monitor the driver alertness are marketed with affordable prices. The sensing and processing power of cars are increasing, enabling various safety-enhancing features, such as blind-spot warning, adaptive headlights, adaptive cruise control, and so on. In this talk, we will discuss the next steps for autonomous vehicles. In particular, we will project the path forward by transitioning from autonomous cars to cognitive and intelligent vehicles. Future cars will be enabled with car-to-car and car-to-infrastructure communication capabilities. We will review such enhancement and will focus on two recent research directives that will make future cars intelligent. The two enablers are compressive sensing and network coding. We will show that cooperative compressive sensing can reduce the wireless channel congestion, which is the main challenge in dense vehicular networks. To discuss the communications aspects of vehicular networks, we will introduce a repetition-based medium access control method using positive orthogonal codes, and then propose an opportunistic network-coding scheme to enhance the reliability of communication. We will finally discuss some open research issues.
Biography:Shahrokh Valaee is with the Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, where he is a Professor and the Associate Chair for Undergraduate Studies. He is the Founder and the Director of the Wireless and Internet Research Laboratory (WIRLab) at the University of Toronto. Professor Valaee recently served as the TPC Co-Chair of ICT 2015. He was the Track Chair of the IEEE Wireless Communications and Networking Conference (WCNC) 2014, the TPC Co-Chair and the Local Organization Chair of IEEE Personal Mobile Indoor Radio Communication (PIMRC) Symposium 2011, and the Co-Chair for Wireless Communications Symposium of IEEE GLOBECOM 2006. From December 2010 to December 2012, he was the Associate Editor of the IEEE Signal Processing Letters. Currently, he serves as an Editor of IEEE Transactions on Wireless Communications. Since Feb 2015 he has been an Editor of the Elsevier Journal of Computer and System Science. Professor Valaee is a Fellow of the Engineering Institute of Canada.
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Date:03/06/2015, 14h
Room:LINCS, Salle du Conseil
Speaker:Eitan Altman (INRIA)
Talk:Timelines Analysis and competition over popularity, influence and visibility in social networks.
Abstract:The major social networks use timelines to display content that a user receives from those sources that he follows. A content that arrives at a timeline is placed at the top of the list and each other content is pushed down by one step. If the timeline is finite (as in twitter) then this causes the last element in the timeline to be pushed out. Moreover, the lower the content is on the timeline the smaller its influence is. In this talk we shall first present analysis of the timeline process and of the probability to be visible on the timeline. We shall further describe the influence process of content which takes into account not only the location on the timeline but also aging of content. We shall then study the impact of the burstiness of the arrival of contents on the timeline process. We shall finally introduce game theoretical models to describe the competition over popularity and over visibility of content in the timeline. We shall study two specific game theoretic problems. The first is a timing game: when is it best to send a content. The second is a resource allocation game for optimal control of the flow of content.The work describes ongoing collaborative work with many woauthors: Alexandre Reiffers, Nahum Shimkin, Anurag Kumar, Yezekael Hayel and others.
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Date:27/05/2015, 14h
Room:LINCS, Salle du Conseil
Speaker:Nidhi Hegde
Talk:Learning WiFi Performance (Alcatel-Lucent Bell Labs)
Abstract:Accurate prediction of wireless network performance is important when performing link adaptation or resource allocation. However, the complexity of interference interactions at MAC and PHY layers, as well as the vast variety of possible wireless configurations make it notoriously hard to design explicit performance models.In this work, we advocate an approach of "learning by observation", where we use machine learning techniques to learn implicit performance models, from a limited number of real-world measurements. While our model does not use information on the WiFi mechanism itself, our results show that the accuracy of performance prediction is significantly improved as compared to measurement-seeded models based on SINR. To demonstrate that learned models can be useful in practice, we build a new algorithm that uses such a model as an oracle to jointly allocate spectrum and transmit power. Our algorithm is utility-optimal, distributed, and it produces efficient allocations that significantly improve performance and fairness.Joint work with Julien Herzen (EPFL) and Henrik Lundgren (Technicolor)
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Date:27/05/2015, 11h
Room:LINCS, Salle du Conseil
Speaker:Don Towsley
Talk:Sampling Node Pairs in Large Graphs (Univ. of Massachusetts, Amherst)
Abstract:Characterizing user pair relationships is important for applications such as friend recommendation and interest targeting in online social networks (OSNs). Due to the large scale nature of such networks, it is infeasible to enumerate all user pairs and so sampling is necessarily used. In this talk I focus on this problem from two perspectives, from an OSN service provider with access to the complete network and from a suspicious BBN summer intern with limited access to the network. Characterizing pair relationships poses a great challenge to an OSN provider even when it possesses the complete topology. The reason is that when sampling techniques, e.g., uniform vertex sampling (UVS) are naively applied, they can introduce large biases, in particular, for estimating similarity distribution statistics of user pairs such as network homophily. Estimating statistics of user pairs is more challenging in the absence of the complete topology information, since an unbiased sampling technique such as UVS is usually not allowed, and exploring the OSN topology is expensive. To address these challenges, we present unbiased sampling methods to characterize user pair properties based on UVS and random walks (RWs) respectively. We evaluate our methods to show their accuracy and efficiency. Finally, we apply our methods to several OSNs and characterize the homophily present in each.
Biography:Don Towsley holds a B.A. in Physics (1971) and a Ph.D. in Computer Science (1975) from University of Texas. He is currently a Distinguished Professor at the University of Massachusetts in the Department of Computer Science. He has held visiting positions at numerous universities and research labs including University of Paris VI, IBM Research, AT&T Research, Microsoft Research, and INRIA. His research interests include networks and performance evaluation.He currently serves as Co-Editor-in-Chief of the new ACM Transactions on Modeling and Performance Evaluation of Computing Systems (ToMPECS). He served as Editor-in-Chief of the IEEE/ACM Transactions on Networking and as an associate editor of numerous journals. He has served as Program Co-chair of INFOCOM 2009, Performance02, and the joint 1992 ACM SIGMETRICS/Performance Conference as well as General Chair of COMSNETS 2012. He is a member of ACM and IEEE.He has received numerous IEEE and ACM awards including the 2007 IEEE Koji Kobayashi Award and several achievement award. He has also received numerous best paper awards including the IEEE Communications Society 1998 William Bennett Paper Award, several test of time awards and conference best paper awards. Last, he has been elected Fellow of both the ACM and IEEE.
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Date:22/05/2015, 10h30
Room:LINCS, Salle du Conseil
Speaker:Longbo Huang (Tsinghua University)
Talk:The Power of Online Learning in Stochastic Network Optimization
Abstract:We investigate the power of online learning in stochastic network optimization with unknown system statistics a priori. We are interested in understanding how information and learning can be efficiently incorporated into system control techniques, and what are the fundamental benefits of doing so. We propose two Online Learning-Aided Control techniques, OLAC and OLAC2, that explicitly utilize the past system information in current system control via a learning procedure called dual learning. We prove strong performance guarantees of the proposed algorithms: OLAC and OLAC2 achieve the near-optimal O(epsilon), O([log(1/epsilon)^2)]$ utility-delay tradeoff and OLAC2 possesses an $O(epsilon^-2/3)$ convergence time. OLAC and OLAC2 are probably the first algorithms that simultaneously possess explicit near-optimal delay guarantee and sub-linear convergence time. Simulation results also confirm the superior performance of the proposed algorithms in practice. To the best of our knowledge, our attempt is the first to explicitly incorporate online learning into stochastic network optimization and to demonstrate its power in both theory and practice.
Biography:Dr. Longbo Huang received his Ph.D. from the EE department at the University of Southern California in August 2011. He was then a postdoctoral researcher in the EECS department at UC Berkeley from July 2011 to August 2012. Since then he has been an assistant professor at the Institute for Interdisciplinary Information Sciences (IIIS) at Tsinghua University. Dr. Huang was a visiting scholar at the LIDS lab at MIT in summer 2012 and 2014, at the EECS department at UC Berkeley in summer 2013, and at Bell-labs France in April 2013. He was also a visiting professor at the Institute of Network Coding at CUHK in winter 2012. Dr. Huang was selected into China'sYouth 1000-talent program in 2013. Dr. Huang's research interests lie in the areas of stochastic learning and optimization for networked systems, delay-efficient network control, mobile networks, data center networking, energy management and smart grid.
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Date:20/05/2015, 14h
Room:LINCS, Salle du Conseil
Speaker:Ramesh Sitaraman (UMass, Amherst and Akamai Technology)
Talk:Understanding Online Video Users: A Key to the Future of the Internet
Abstract:Online video is the killer application of the Internet. It is predicted that more than 85% of the consumer traffic on the Internet will be video-related by 2016. Yet, the future economic viability of online videos rest squarely on our ability to understand how viewers interact with video content. For instance: (i) If a video fails to start up quickly, would the viewer abandon (ii) If a video freezes in the middle, would the viewer watch fewer minutes (iii) If a video fails to load, is the viewer less likely to return to the same site (iv) if a video plays at higher quality, will the viewer watch more minutes, etc.In this talk, we outline scientific answers to these and other such questions, establishing a causal link between video performance and viewer behavior. One of the largest such studies, our work analyzes the video viewing habits of over 65 million viewers who in aggregate watched almost 367 million videos. To go beyond correlation and to establish causality, we develop a novel technique based on Quasi-Experimental Designs (QEDs). While QEDs are well known in the medical and social sciences, our work represents its first use in network performance research and is of independent interest. Our work also a played key role in the recent net neutrality debate in assessing the likely impact of a "fast-lane" on the Internet.This talk is of general interest and is accessible to a broad audience
Biography:Ramesh K. Sitaraman is a professor of computer science at the University of Massachusetts at Amherst and is Akamais chief consulting scientist. His research focuses on all aspects of Internet-scale distributed systems, including algorithms, architectures, performance, energy efficiency, user behavior, and economics. As a principal architect, he helped create the Akamais distributed delivery networks and was an Akamai Fellow. He is best known for his role in pioneering the first major content delivery networks (CDNs) that currently deliver a significant fraction of the worlds web content, streaming videos, and online applications. He received a PhD in Computer Science from Princeton University and a B. Tech from the Indian Institute of Technology, Madras.
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Date:15/04/2015, 14h - 14h30
Room:LINCS, Salle du Conseil
Speaker:Luis Alvarez Corrales (Telecom ParisTech)
Talk:Analyzing Interference from Static Cellular Cooperation using the Nearest Neighbour Model
Abstract:The problem of base station cooperation has recently been set within the framework of Stochastic Geometry. Existing works consider that a user dynamically chooses the set of stations that cooperate for his/her service. However, this assumption often does not hold. Cooperation groups could be predefined and static, with nodes connected by fixed infrastructure. To analyse such a potential network, in this work we propose a grouping method based on proximity. It is a variation of the so called Nearest Neighbour Model. We restrict ourselves to the simplest case where only singles and pairs of base stations are allowed to be formed. For this, two new point processes are defined from the dependent thinning of a Poisson Point Process, one for the singles and one for the pairs. Structural characteristics for the two are provided, including their density, Voronoi surface, nearest neighbour, empty space and J-function. We further make use of these results to analyse their interference fields and give explicit formulas to their expected value and their Laplace transform. The results constitute a novel toolbox towards the performance evaluation of networks with static cooperation.
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Date:15/04/2015, 14h30 - 15h
Room:LINCS, Salle du Conseil
Speaker:Yu-Ting Lin (Telecom ParisTech/Orange)
Talk:A Flow-Level Performance Model for Mobile Networks Carrying Adaptive Streaming Traffic
Abstract:As the adaptive streaming technology becomes the mainstream solution for online video service and 4G broadband service becomes very accessible, for mobile service providers, having a performance model integrating adaptive streaming and elastic traffic becomes a necessity. We aim to build an adaptive streaming model by using flow-dynamics and to examine the streaming performance. Our model takes both the codec limitation and integration of elastic data into account, which assist the operators to understand the trade-offs among different metrics such as deficit rate, mean codec rate and mean elastic throughput when different configurations and prioritization factors are chosen. The simulation results obtained with the real statistics of Orange mobile network demonstrated the maximum traffic intensity under certain QoS constraints and its corresponding optimal prioritization factor.
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Date:09/04/2015, 10h30
Room:C48, rue Barault
Speaker:Janos Korner (U. La Sapienza)
Talk:Entropies and capacity of graphs
Abstract:In the early seventies the speaker introduced two complementarynotions of graph entropy. One of these leads to information theoreticcharacterisations and generalisations of perfect graphs and toasymptotically optimal sorting algorithms for partially ordered sets.Here we deal with the complementary notion to show how it might leadto a new upper bound for the Shannon capacity of self-complementaryvertex-transitive graphs matching the Lovsz bound based on his thetafunction.
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Date:08/04/2015, 14h
Room:LINCS, Salle du Conseil
Speaker:Prof. Kenneth W. Shum (Institute of Network Coding)
Talk:BASIC regenerating codes for distributed storage systems
Abstract:Reliability in disk arrays is provisioned by storing the data with redundancy. For example, in RAID-6, we protect the data from being lost by introducing parity-check disks, so that any failure of two disks can be restored. In a large-scale distributed storage system, disk failures and repairs are common day-to-day event, and incur excessive amount of traffic for the recovery of failed disks. A class of codes, called regenerating codes, was introduced by Dimakis et al. for the purpose of reducing the required repair traffic. Like Reed-Solomon codes, most of the existing regenerating codes rely on the arithmetic of finite fields. The computational complexity of encoding and decoding may render the system impracticable if the size of the finite field is large. In this talk, we discuss a construction of regenerating codes called Binary Addition and Shift Implementable Convolutional (BASIC) codes, in which finite field additions and multiplications are replaced by bit-wise exclusive OR and bit-wise shifting. The advantage of regenerating code is thereby attained with lower computational cost. This is a joint work with Minghua Chen, Hanxu Hou and Hui Li.
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Date:01/04/2015, 14h
Room:LINCS, Salle du Conseil
Speaker:Anastasios Giovanidis (Telecom ParisTech)
Talk:Optimal Geographic Caching in Cellular Networks
Abstract:We consider the problem of an optimal geographic placement of content in wireless cellular networks modelled by Poisson point processes. Specifically, for the typical user requesting some particular content and whose popularity follows a given law (e.g. Zipf), we calculate the probability of finding the content cached in one of the base stations. Wireless coverage follows the usual signal-to-interference-and noise ratio (SINR) model, or some variants of it. We formulate and solve the problem of an optimal randomized content placement policy, to maximize the user's hit probability. The result dictates that it is not always optimal to follow the standard policy "cache the most popular content, everywhere". In fact, our numerical results regarding three different coverage scenarios, show that the optimal policy significantly increases the chances of hit under high-coverage regime, i.e., when the probabilities of coverage by more than just one station are high enough.
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Date:25/03/2015, 14h
Room:LINCS, Salle du Conseil
Speaker:Guillaume Baudart (ENS)
Talk:A Synchronous View of Loosely Time-Triggered Architectures
Abstract:Loosely Time-Triggered Architectures (LTTAs) are a proposal forconstructing distributing embedded control systems. They build onquasi-periodic systems, where computing units execute almostperiodically, by adding a thin layer of middleware that facilitatesthe deployment of synchronous applications.In this paper, we show how the deployment of a synchronous applicationon a quasi-periodic architecture can be modeled using a synchronousformalism. Then we detail two LTTA protocols, Back-PressureLTTA reminiscent of elastic circuits, and a new class ofTime-Based LTTA. Finally, we compare the LTTA approach to clocksynchronization protocols which are becoming more an more commonnowadays. Joint work with Albert Benveniste (INRIA)
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Date:18/03/2015, 14h
Room:LINCS, Salle du Conseil
Speaker:Mario Gerla (UCLA)
Talk:VANET Services and Mobile Vehicle Clouds
Abstract:New vehicle applications have recently emerged in several areas ranging from navigation safety to location aware content distribution, urban surveillance and intelligent transport. A new impulse is given by autonomous vehicle with plenty of sensors, memory and processing power. The richness of on board resources and the diversity of applications sets the Vehicular ad Hoc Network (VANET) apart from conventional MANETs and does introduce new challenges in the services they can provide. A representative service scenario is urban sensing: vehicles monitor the environment, classify the events, e.g., license plates, chemical readings etc, and support forensic service requests from Authorities. This notion of service suggests that the VANET can be viewed as a Mobile Computing Cloud (MCC) where vehicles interact and collaborate to sense the environment, process the data, V2V propagate the results and share resources to provide mobile services. This talk will revisit VANET applications and services in light of the Mobile Cloud model. It will then propose a Vehicular Cloud platform and will address the cooperation with Edge Cloud and Internet Cloud.
Biography:Dr. Mario Gerla is a Professor in the Computer Science Dept at UCLA. He holds an Engineering degree from Politecnico di Milano, Italy and the Ph.D. degree from UCLA. He became IEEE Fellow in 2002. At UCLA, he was part of the team that developed the early ARPANET protocols under the guidance of Prof. Leonard Kleinrock. He joined the UCLA Faculty in 1976. At UCLA he has designed network protocols including ad hoc wireless clustering, multicast (ODMRP and CODECast) and Internet transport (TCP Westwood). He has lead the ONR MINUTEMAN project, designing the next generation scalable airborne Internet for tactical and homeland defense scenarios. He is now leading several advanced wireless network projects under Industry and Government funding. His team is developing a Vehicular Testbed for safe navigation, content distribution, urban sensing and intelligent transport. Parallel research activities are wireless medical monitoring using smart phones and cognitive radios in urban environments.He has served as a Technical Program Committee member of many international conferences, and is active in the organization of conferences and workshops, including MedHocNet and WONS. He serves on the IEEE TON Scientific Advisory Board. He was recently recognized with the annual MILCOM Technical Contribution Award for 2011 and the IEEE Ad Hoc and Sensor Network Society Achievement Award in 2011.
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Date:11/03/2015, 11h
Room:LINCS, Salle du Conseil
Speaker:Udo Krieger (Otto-Friedrich-University Bamberg)
Talk:On the Design of Integrated Forwarding andCaching Policies in Named-Data Networking
Abstract:Current IP-based networks are unable to fully exploit the capabilities ofthe increasing number of multi-homed mobile terminals. We argue thatNamed-Data Networking (NDN) can fill the gap. First, we elaborate on therequirements for NDN packet forwarding to multi-homed mobile terminalsand categorize forwarding strategies according to their ability to fulfill theserequirements. Further, we describe the initial design of an advanced multi-path forwarding strategy that is derived from performance insights gainedby a CCNx implementation. Secondly, we investigate the performance of aLRU cache replacement policy in the related tree structure. We start withthe performance approximation of Che et al. and assume Zipf-distributedfrequencies of object requests that constitute associated Poisson streams.Then we derive new explicit formulae regarding the hit and miss ratios in thiscascade of LRU caches. Considering adaptive or cooperative cache policies insuch an access network with multi-homed mobile clients, the sketched resultsprovide a basis for an integrated design of efficient forwarding schemes withoptimal cache placement.
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Date:11/03/2015, 14h
Room:LINCS, Salle du Conseil
Speaker:Patrick Loiseau (EURECOM)
Talk:Game-theoretic statistics: Learning from data generated by strategic agents
Abstract:Statistical learning methods developed in the last decades have proved very useful for many applications. However, most algorithms were developed under the assumption that the data is independent from the algorithm. This is no longer true in applications where data is generated or provided by (human) strategic agents. As more and more modern applications indeed learn from data provided by external parties, it becomes increasingly crucial to account for the data-provider's incentives in order to design well-performing learning algorithms in practice.In this talk, we use game theory to model explicitly the economic incentives of the learner and of the agents generating data. We show how, by analyzing the game, it is possible to design learning algorithms that work better because they account for the agents' incentives. Specifically, we illustrate this in two examples with applications in security and privacy: (i) Classification of malicious behavior: In this example, a defender runs a classification algorithm to detect malicious behavior while an attacker chooses his attack strategy to balance the utility of the attack and the probability of being detected. We obtain analytic results that show how to optimally perform the classification given the attacker's utility. (ii) Linear regression from agents-provided data: In this example, we study the case of an analyst who tries to infer a model through linear regression from data provided by individuals who add noise to protect their privacy (this technique is called "local privacy"). We again derive results on optimal linear regression and on the price of anarchy of the system that provide methods to better learn from privacy-conscious users by incentivizing them to provide higher-quality data.
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Date:04/03/2015, 14h
Room:LINCS, Salle du Conseil
Speaker:Mostafa Ammar (Georgia Tech)
Talk:The Cirrus Cloud Project: Opportunistic Mobile Cloud Computing
Abstract:Mobile devices are increasingly being relied on for tasks that go beyond simple connectivity and demand more complex processing. In cases where such processing exceeds a device’s capability, remote cloud resources can be used to off-load the “heavy lifting” needed by mobile computation tasks. The Cirrus Cloud project focuses on the design and analysis of techniques that enable the provision of cloud computation services to mobile devices. The project is distinguished by 1) its consideration of specific challenges of the wireless and mobile environment and 2) its focus on leveraging the computational capability of a variety of entities present in a mobile device’s environment in an opportunistic manner. In this talk we will first give an overview of the Cirrus Cloud project and its aims. We will then discuss two specific directions of work that represent two points on a spectrum of mobile cloud computing scenarios. In the first we design and evaluate the COSMOS system which enables mobile computation requirements to map seamlessly to traditional cloud computing services. In the second we consider how clusters of mobile devices may be configured as a powerful compute resource. We will conclude with a discussion of our plans for future research.
Biography:Mostafa Ammar is a Regents' Professor with the School of Computer Science at the Georgia Institute of Technology. He has been with Georgia Tech since 1985. Dr. Ammar received the S.B. and S.M. degrees from the Massachusetts Institute of Technology in 1978 and 1980, respectively and the Ph.D. degree from the University of Waterloo, Ontario, Canada in 1985. Dr. Ammar's research interests are in network architectures, protocols and services. He has contributions in the areas of multicast communication and services, multimedia streaming, content distribution networks, network simulation, disruption-tolerant networks, virtual network design, and most recently in mobile cloud computing. He has published extensively in these areas. To date, 33 PhD students have completed their degrees under his supervision; many have gone on to distinguished careers in academia and industry. Dr. Ammar has served the research community in multiple roles. Most notably, he served as the Editor-in-Chief of the IEEE/ACM Transactions on Networking (ToN) from 1999 to 2003, and he was the co-TPC Chair for the IEEE ICNP 1997, ACM CoNEXT 2006 and ACM SIGMETRICS 2007 conferences. His awards include the IBM Faculty Partnership Award (1996), Best Paper Award at the 7th WWW conference (1998), the Georgia Tech Outstanding Doctoral Thesis Advisor Award (2006), the Outstanding Service Award from the IEEE Technical Committee on Computer Communications (2010), and the ACM Mobihoc Best Paper Award (2012). Dr. Ammar was elected Fellow of the IEEE in 2002 and Fellow of the ACM in 2003.
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Date:25/02/2015, 14h
Room:LINCS, Salle du Conseil
Speaker:Fabian Suchanek (Telecom ParisTech)
Talk:A Hitchhiker's guide to ontology
Abstract:In this talk, I will present our recent work in the area ofknowledge bases. It covers 4 areas of research around ontologies andknowledge bases: The first area is the construction of the YAGOknowledge base. YAGO is now mulitlingual, and has grown into a largerproject at the Max Planck Institute for Informatics and TélécomParisTech. The second area is the alignment of knowledge bases. Thisincludes the alignment of classes, instances, and relations acrossknowledge bases. The third area is rule mining. Our project findssemantic correlations in the form of Horn rules in the knowledge base.I will also talk about watermarking approaches to trace the provenanceof ontological data. Finally, I will show applications of theknowledge base for mining news corpora.
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Date:18/02/2015, 14h30
Room:Salle C48, Barrault
Speaker:Claudia Malvenuto (Università  di Roma La Sapienza)
Talk:Quasi-symmetric functions, poset partitions and finite topologies, part II: the combinatorial aspects
Abstract:A combinatorial Hopf algebra based on double posets, endowed with abilinear form based on pictures between double posets was introduced in 2011by Malvenuto and Reutenauer.When the second order of a double poset is total, one obtains thenotion of special double poset; it is equivalent to that of labelledposet of Stanley. Its generating function, with respect to Stanley'sclassical definition of P-partitions associated to a special poset Pis quasi-symmetric, and, in fact, it is a homomorphism betweenthe Hopf algebra of double posets and that of quasi-symmetric functions.Generalizing to preorders, we define the notion of T-partitionsassociated to a finite topology T, and deduce a Hopf algebra morphismfrom a new Hopf algebra on topologies to the Hopf algebra of packedwords.
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Date:11/02/2015, 14h - 14h30
Room:LINCS, Salle du Conseil
Speaker:Christelle Rovetta (INRIA)
Talk:Perfect sampling for closed queueing networks
Abstract:We investigate coupling from the past (CFTP) algorithmsfor closed queueing networks. The stationary distribution has a productform only in a very limited number of particular cases when queue capacityis finite, and numerical algorithms are intractable due to the cardinalityof the state space. Moreover, closed networks do not exhibit any mono-tonic property enabling ecient CFTP. We derive a bounding chain forthe CFTP algorithm for closed queueing networks. This bounding chainis based on a compact representation of sets of states that enables exactsampling from the stationary distribution without considering all initialconditions in the CFTP. The coupling time of the bounding chain is al-most surely finite, and numerical experiments show that it is close to thecoupling time of the exact chain.
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Date:11/02/2015, 14h30 - 15h
Room:LINCS, Salle du Conseil
Speaker:The Dang Huynh (Alcatel-Lucent)
Talk:Exploiting User Movement for Position Detection
Abstract:The major issue of indoor localization system is the trade-off between implementation cost and accuracy. A low-cost system which demands only few hardware devices could save the cost but often it turns out to be less reliable. Aiming at improving classical triangulation method that requires several reference points, this paper proposes a new method, called Two-Step Movement (2SM), which requires only one reference point (RP) by exploiting useful information given by the position change of a mobile terminal (MT), or the user movement. This method can minimize the number of reference points required in a localization system or navigation service and reduce system implementation cost. Analytical result shows that the user position can be thus derived and given in simple closed-form expression. Finally, simulation is conducted to demonstrate its effectiveness under noisy environment.
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Date:04/02/2015, 15h30 -- Notice time is later than usual!
Room:LINCS, Salle du Conseil
Speaker:Gyorgy Dan (KTH)
Talk:Optimal content prefetching for cloud assisted content delivery
Abstract:Motivated by improved models for content workload prediction, in this paper we consider the problem of dynamic content allocation for a hybrid content delivery system that combines cloud-based storage with low cost dedicated servers that have limited storage and unmetered upload bandwidth. We formulate the problem of allocating contents to the dedicated storage as a finite horizon dynamic decision problem, and show that a discrete time decision problem is a good approximation forpiecewise stationary workloads. We provide an exact solution to the discrete time decision problem in the form of a mixed integer linear programming problem, propose computationally feasible approximations, and give bounds on their approximation ratios. Finally, we evaluate the algorithms using synthetic and measured traces from a commercial music on-demand service and give insight into their performance as a function of the workload characteristics.
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Date:21/01/2015, 14h
Room:LINCS, Salle du Conseil
Speaker:Peter Marbach (University of Toronto)
Talk:A New Perspective on Distributed Scheduling in Wireless Multihop Networks
Abstract:One vision for wireless networks has been the creation of wireless multihop networks that are formed and operate in a fully decentralized manner using cheap commodity hardware. One of the main challenges to achieve this vision is the design of scheduling protocols for data transmissions that are throughput and delay optimal, and can be implemented in a fully distributed manner.In the talk, we present results that provide a new perspective on the design of distributed scheduling algorithms. In particular, our results suggest that it is possible to create protocols that throughput and delay order-optimal, and can be implemented in a fully distributed manner. We will first discuss the intuition behind the performance limitations of traditional distributed scheduling protocols, and present the main idea behind our approach. We will then provide a more detail discussion of our results as well as future work.An interesting aspect of the work is that the underlying mathematical models and results may be of independent interest and might be applicable to more general combinatorial optimization problem.
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Date:15/01/2015, 15h
Room:rue Barrault, Salle C48
Speaker:Hossein Vahabi Puya (Yahoo Labs)
Talk:Social Recommender Systems
Abstract:Modeling social media and blogging is a fashionable topic of research. The challenges include how to model, exploit, store, and analyze social content data. In this talk we will discuss about novel approaches on how to exploit such data in order to build: (1) new types of recommender systems; (2) discover and understand the evolution of topics over time.
Biography:Puya - Hossein Vahabi is a researcher at Yahoo Labs since 2014, where he is working on computational advertising (search and native ads), social media (Tumblr) and stream data. Before joining Yahoo, he was working on his own co-founded startup (2007 to 2014). He has been a research associate of the National Research Council of Italy for many years. He hold a PhD in Computer Science and Engineering under the supervision of Prof. Ricardo Baeza-Yates (VP of Research of Yahoo Labs) and Dr. Fabrizio Silvestri (Senior Researcher at Yahoo Labs).
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Date:14/01/2015, 14h (joint INFRES and LIX seminar)
Room:LINCS, Salle du Conseil
Speaker:Yanlei Diao (Universityof Massachusetts, Amherst)
Talk:Platforms and Applications for "Big and Fast" Data Analytics
Abstract:Recently there has been a significant interest in building big data systems that can handle not only "big data" but also "fast data" for analytics. Our work is strongly motivated by recent real-world case studies that point to the need for a general, unified data processing framework to support analytical queries with different latency requirements. Towards this goal, our project is designed to transform the popular MapReduce computation model, originally proposed for batch processing, into distributed (near) real-time processing. In this talk, I start by examining the widely used Hadoop system and presenting a thorough analysis to understand the causes of high latency in Hadoop. I then present a number of necessary architectural changes, as well as new resource configuration and optimization techniques to meet user-specified latency requirements while maximizing throughput. Experiments using typical workloads in click stream analysis and twitter feed analysis show that our techniques reduce the latency from tens or hundreds of seconds in Hadoop to sub-second in our system, with 2x-7x increase in throughput. Our system also outperforms state-of-the-art distributed stream systems, Twitter Storm and Spark Streaming, by a wide margin. Finally, I will show some initial results and challenges of supporting big and fast data analytics in the emerging domain of genomics.
Biography:Yanlei Diao is Associate Professor of Computer Science at the University of Massachusetts Amherst. Her research interests are in information architectures and data management systems, with a focus on big data analytics, data streams, uncertain data management, and RFID and sensor data management. She received her PhD in Computer Science from the University of California, Berkeley in 2005, her M.S. in Computer Science from the Hong Kong University of Science and Technology in 2000, and her B.S. in Computer Science from Fudan University in 1998. Yanlei Diao was a recipient of the 2013 CRA-W Borg Early Career Award (one female computer scientist selected each year), IBM Scalable Innovation Faculty Award, and NSF Career Award, and she was a finalist of the Microsoft Research New Faculty Award. She spoke at the Distinguished Faculty Lecture Series at the University of Texas at Austin. Her PhD dissertation "Query Processing for Large-Scale XML Message Brokering" won the 2006 ACM-SIGMOD Dissertation Award Honorable Mention. She is currently Editor-in-Chief of the ACM SIGMOD Record, Associate Editor of ACM TODS, Area Chair of SIGMOD 2015, and member of the SIGMOD Executive Committee and SIGMOD Software Systems Award Committee. In the past, she has served as Associate Editor of PVLDB, organizing committee member of SIGMOD, CIDR, DMSN, and the New England Database Summit, as well as on the program committees of many international conferences and workshops. Her research has been strongly supported by industry with awards from Google, IBM, Cisco, NEC labs, and the Advanced Cybersecurity Center.
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Date:08/01/2015, 14h30
Room:Salle C48, Barrault
Speaker:Claudia Malvenuto (Università  di Roma La Sapienza)
Talk:Quasi-symmetric functions, poset partitions and finite topologies
Abstract:A combinatorial Hopf algebra based on double posets, endowed with abilinear form based on pictures between double posets (in analogy topictures of tableaux as defined by Zelevinski) was introduced in 2011by Malvenuto and Reutenauer.When the second order of a double poset is total, one obtains thenotion of special double poset; it is equivalent to that of labelledposet of Stanley. Its generating function, with respect to Stanley'sclassical definition of P-partitions associated to a special poset Pis quasi-symmetric, and, in fact, it is a homomorphism betweenthe Hopf algebra of double posets and that of quasi-symmetric functions.Generalizing to preorders, we define the notion of T-partitionsassociated to a finite topology T, and deduce a Hopf algebra morphismfrom a new Hopf algebra on topologies to the Hopf algebra of packedwords.
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Date:07/01/2015, 14h
Room:LINCS, Salle de Conseil
Speaker:Amal Abdel-Razzak (UPMC)
Talk:Cooperation between LTE and emergent DVB technologies for an efficient delivery of mobile TV
Abstract:The broadcast/cellular cooperation for a common delivery of Mobile TV is at theheart of the emerging mobile broadcast technologies, namely the mobile extensionof the second generation digital video broadcasting for terrestrial reception (DVB-T2Lite) and its follower DVB-Next Generation Handheld (DVB-NGH). These broadcasttechnologies aim to cooperate with the Long Term Evolution (LTE), as the latter isintended to be the bearer of Mobile TV thanks to its enhanced-Multimedia Broadcastand Multicast Service feature (e-MBMS).Even though the 3GPP/DVB cooperation is not a new topic and was investigatedwith the introduction of the previous DVB technology, known as DVB-Handheld(DVB-H), most of the works addressing this issue considered a common service areacovered by both DVB and cellular systems and focused solely on the impact of such cooperation in terms of capacity gains brought by 3GPP and error repair gains broughtby DVB. This strategy was judged to be expensive since a new and very dense DVBnetwork was needed. In order to overcome this problem and decrease as much as possible the need for a new broadcast network, we propose in this thesis a hybrid DVB/LTEnetwork with a coverage extension strategy, where the LTE system, planned for almost a universal coverage, is used to deliver Mobile TV in areas not covered by recentDVB-T2 Lite (or eventually DVB-NGH) network. In this context, we explore twomain issues:1. Mobile TV services have to share LTE resources with other higher priorityservices such as voice traffic. The dynamicity of the latter will impact theQuality of Service (QoS) of Mobile TV. We propose a new QoS-based planning1for the hybrid DVB/LTE so as to guarantee an acceptable watching experiencewithout over-dimensioning the LTE system. We derive using Markov chainanalysis and hitting time theory, several QoS metrics pertaining to mobile TVperformance, such as interruption frequency and duration.2. A new business model which clarifies the relationships between the differentactors of the ecosystem namely DVB and LTE operators as well as the TVchannel providers and constructs the service area from an economic point ofview is needed. In fact, the absence of a clear and viable economic model thatresolves the monetary conflicts between cellular and broadcast operators wasone of the main drawbacks behind the failure of the first attempt of mobile TVdelivery by cooperating UMTS/DVB-H. We develop in this thesis a profit sharing strategy for the cooperative network, using coalition game concept Shapleyvalue and Nash equilibrium for a self-enforcing strategy. We further develop anew framework using real option theory coupled with coalition games for investment decision in mobile TV networks (whether an operator should enterthe mobile TV market and, if yes, when to do so) and show how operators canincorporate the uncertainties related to demand and network operation costs.We propose a bi-level dynamic programming algorithm to solve numerically thedeveloped real option game.
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Date:17/12/2014, 14h
Room:LINCS, Salle du Conseil
Speaker:Victor Bahl (Microsoft Research)
Talk:Cloud 2020: The Emergence of Micro Datacenter for Mobile Computing
Abstract:Resource poverty is a fundamental constraint that severely limits the types of applications that can be run on mobile devices. This constraint is not just a temporary limitation of current technology but is intrinsic to mobility. In this talk, I will put forth a vision of the cloud that breaks free of this fundamental constraint. In this vision, mobile users seamlessly utilize nearby computers to obtain the resource benefits of cloud computing without incurring WAN delays and jitter. Rather than relying on a distant cloud the client connects and uses a nearby micro datacenter (mDC). Crisp interactive response for immersive applications that augment human cognition are then easier to achieve. While much engineering and research remains, the concepts and ideas introduced open the door to a new world of disaggregated computing in which seamless cognitive assistance for users can be delivered at any time and any place.
Biography:Victor Bahl is a Principal Researcher and the Director of the Mobility & Networking Research (MNR) group in Microsoft Research. MNR's mission is to invent & research technologies that make Microsoft's networks, services, and devices indispensable to the world. In addition to shepherding brilliant researchers, Victor helps shape Microsoft's long-term vision related to networking technologies by advising the CEO and senior executive team, and by executing on this vision through research, technology transfers, and associated policy engagements with governments and industries around the world. He and his group have had far-reaching impact on the research community, government policy, and Microsoft products through numerous significant publications and technology transfers. His personal research spans a variety of topics in mobile & cloud computing, wireless systems & services, and datacenter & enterprise networking. Over his career he has built many highly cited seminal systems, published prolifically in top conferences and journals, authored 115 patents, given over three dozen keynote talks, won numerous prestigious awards and honors including ACM SIGMOBILE's Lifetime Achievement Award and IEEE Outstanding Leadership and Professional Service Award. Victor received his PhD from the University of Massachusetts Amherst in 1997. He is a Fellow of the ACM, IEEE and AAAS.
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Date:10/12/2014, 14h
Room:LINCS, Salle du Conseil
Speaker:Marco Mellia (Politecnico di Torino)
Talk:Is there a case for mobile phone content pre-staging
Abstract:Content caching is a fundamental building block of the Internet. Caches are widely deployed at network edges to improve performance for end-users, and to reduce load on web servers and the backbone network. Considering mobile 3G/4G networks, however, the bottleneck is at the access link, where bandwidth is shared among all mobile terminals. Assuch, per-user capacity cannot grow to cope with the traffic demand. Unfortunately, caching policies would not reduce the load on the wireless link which would have to carry multiple copies of the same object that is being downloaded by multiple mobile terminals sharing the same access link.In this paper we investigate if it is worth to push the caching paradigm even farther. We hypothesize a system in which mobile terminals implement a local cache, where popular content can be pushed/pre-staged. This exploits the peculiar broadcast capability of the wireless channels to replicate content "for free" on all terminals, saving the cost of transmitting multiple copies of those popular objects. Relying on a large data set collected from a European mobile carrier, we analyse the content popularity characteristics of mobile traffic, and quantify the benefit that the push-to-mobile system would produce. We found that content pre-staging, by proactively and periodically broadcasting "bundles" of popular objects to devices, allows to both greatly i) improve users' performance and ii) reduce up to 20% (40%) the downloaded volume (number of requests) in optimistic scenarios with a bundle of 100 MB. However, some technical constraints and content characteristics could question the actual gain such system would reach in practice..
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Date:03/12/2014, 14h
Room:LINCS, Salle du Conseil
Speaker:Raluca Maria Indre (Orange)
Talk:Evaluating user-perceived performance in FTTH access networks
Abstract:We evaluate the performance perceivedby end-users connected to a backhaul link thataggregates the traffic of multiple access areas. We model, at flowlevel, the way a finite population of users with heterogeneousaccess rates and traffic demands shares the capacity of thiscommon backhaul link. We then evaluate several practicallyinteresting use cases, focusing particularly on the performance ofusers subscribing to recent FTTH offers in which the user accessrates are in the same order of magnitude as the backhaul linkcapacity. We show that, despite such high access rates, reasonableperformance can be achieved as long as the total offered traffic iswell below the backhaul link capacity. The obtained performanceresults are used to derive simple dimensioning guidelines.
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Date:19/11/2014, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Bruno Kauffmann (Orange)
Talk:Catalog Dynamics: Impact of Content Publishing and Perishing on the Performance of a LRU Cache
Abstract:The Internet heavily relies on Content Distribution Networks and transparent caches to cope with the ever-increasing traffic demand of users. Content, however, is essentially versatile: once published at a given time, its popularity vanishes over time. All requests for a given document are then concentrated between the publishing time and an effective perishing time. In this paper, we propose a new model for the arrival of content requests, which takes into account the dynamical nature of the content catalog. Based on two large traffic traces collected on the Orange network, we use the semi-experimental method and determine invariants of the content request process. This allows us to define a simple mathematical model for content requests; by extending the so-called Che approximation, we then compute the performance of a LRU cache fed with such a request process, expressed by its hit ratio. We numerically validate the good accuracy of our model by comparison to trace-based simulation. Joint work with Felipe Olmos, Alain Simonian and Yannick Carlinet
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Date:12/11/2014, 14h
Room:LINCS, Salle du Conseil
Speaker:Luca De Cicco (Politecnico di Bari)
Talk:Controlling Adaptive Video Streaming Systems: One Knob is Enough
Abstract:The video part of Internet traffic is booming due to the ever increasingavailability of video content from sitessuch as YouTube (video sharing), Netflix (movie on demand), Livestream(live streaming).Adaptive video streaming systems dynamically change the video contentbitrate and resolution to match thenetwork available bandwidth and user screen resolution.The mainstream approach employed by adaptive streaming systems, employed byNetflix and Youtube, is touse two controllers: one is the stream-switching algorithm that selects thevideo level, the other regulates theplayout buffer length to a set-point.In this talk we show that such an approach is affected by a fundamentaldrawback: the video flows are not able to get thebest possible video quality when competing with TCP flow. We then design anadaptive video streaming system which fixesthis issue by only using one controller. An experimental evaluation showsthe benefits of the proposed control system.
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Date:05/11/2014, 14h
Room:LINCS, Salle du Conseil
Speaker:Richard Combes (Suplec)
Talk:Unimodal Bandits without Smoothness
Abstract:In this talk we present new results on the stochastic bandit problems with a continuum set of arms and where the expected reward is a continuous and unimodal function of the arm. Our setting for instance includes the problem considered in (Cope, 2009) and (Yu, 2011). No assumption beyond unimodality is made regarding the smoothness and the structure of the expected reward function. Our first result is an impossiblity result: without knowledge of the smoothness of the reward function, there exists no stochastic equivalent to Kiefer's golden section search (Kiefer, 1953). Further, we propose Stochastic Pentachotomy (SP), an algorithm for which we derive finite-time regret upper bounds. In particular, we show that, for any expected reward function $mu$ that behaves as $mu(x)=mu(x^star)-C|x-x^star|^xi$ locally around its maximizer $x^star$ for some $xi, C>0$, the SP algorithm is order-optimal, i.e., its regret scales as $O(sqrtTlog(T))$ when the time horizon $T$ grows large. This regret scaling is achieved without the knowledge of $xi$ and $C$. Our algorithm is based on asymptotically optimal sequential statistical tests used to successively prune an interval that contains the best arm with high probability. To our knowledge, the SP algorithm constitutes the first sequential arm selection rule that achieves a regret scaling as $O(sqrtT)$ up to a logarithmic factor for non-smooth expected reward functions, as well as for smooth functions with unknown smoothness. This is a joint work with Alexandre Proutire available at : http://arxiv.org/abs/1406.7447
Biography:Bio: Richard Combes received the Engineering degree from Telecom ParisTech (2008), the Master's degree in mathematics from university of Paris VII (2009) and the Ph.D. degree in mathematics from university of Paris VI (2012). He was a visiting scientist in INRIA (2012) and a post-doc in KTH (2013). He is currently an Assistant Professor in Suplec. He received the best paper award at CNSM 2011. His current research interests include communication networks, stochastic systems and their control and machine learning.
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Date:30/10/2014, 14h
Room:Amphi Saphir, rue Barrault
Speaker:Jeremy Pitt (Imperial College London)
Talk:Formal Models of Social Processes: Computational Justice for Fair and SustainableResource Allocation in Socio-Technical Systems.
Abstract:Many open computing systems, for example grid and cloud computing, and ad hoc networks,such as sensor or vehicular networks, face a similar problem: how to collectivise resources,and distribute them fairly, in the absence of a centralized component. In this talk, we apply themethodology of sociologically-inspired computing, in which the study of human (social) modelsare formalised as the basis of engineering solutions to technical problems. In this case, wepresent formal models of Ostrom's design principles for self-governing institutions andRescher's theory of distributive justice, for defining executable specifications of electronicinstitutions which support fair and sustainable resource allocation in open computing systems.We will also discuss some ramifications of this research: in particular the implications ofunrestricted self-modification of mutable rules for the design of adaptive systems, andthe potential of such systems for reasoning about resource allocation in socio-technicalsystems, where computational intelligence operates on behalf of (or in consort with)human intelligence. This is the basis for a programme of research we callcomputational justice: capturing some notions of `correctness' in the outcomesof algorithmic decision-making as for basis self-governance in socio-technical systems.
Biography:Jeremy Pitt is Reader in Intelligent Systems in the Department of Electrical & Electronic Engineering at Imperial College London, where he is also Deputy Head of the Intelligent Systems & Networks Group. His research interests focus on developing formal models of social processes using computational logic, and their application to multi-agent systems, for example in agent societies, agent communication languages, and self-organising electronic institutions. He also has an strong interest in the social impact of technology, and has edited two recent books, This Pervasive Day (IC Press, 2012) and The Computer After Me (IC Press, 2014). He has been an investigator on more than 30 national and European research projects and has published more than 150 articles in journals and conferences. He is a Senior Member of the ACM, a Fellow of the BCS, and a Fellow of the IET; he is also an Associate Editor of ACM Transactions on Autonomous and Adaptive Systems and an Associate Editor of IEEE Technology and Society Magazine.
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Date:29/10/2014, 14h
Room:LINCS, Salle du Conseil
Speaker:Paola Bermolen and Federico Larroca (Universidad de la Republica, Montevideo)
Talk:On the spatial reuse on large random wireless networks
Abstract:In this work we analyze the estimation of the spatial reuse of a wirelessnetwork equiped witha Medium Access Control (MAC) mechanism based on 802.11's DistributedCoordination Function (DCF). Moreover we assume that the RTS/CTS handshakeis enabled in order to avoid the hidden node problem.Our analysis is based on the definition of Parking Process over a randomgraph (the interference graph of the network) for which only mildassumptions over the distribution of the nodes's degree are assumed. Then alarge graph limit when the number of nodes goes to infinity is proved whichresults in a system of differential equations representing the evolutionof the nodes'degree. From the solution of this system we can calculate thespatial reuse (or equivalently the jamming constant associated to theparking process).Joint work of Paola Bermolen, Matthieu Jonckheere, Federico Larroca andPascal Moyal
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Date:22/10/2014, 14h
Room:LINCS, Salle du Conseil
Speaker:Anais Vergne (Telecom ParisTech)
Talk:Simplicial homology and wireless networks
Abstract:Simplicial complex representation gives a mathematical description ofthe topology of a wireless sensor network, i.e., its connectivity andcoverage. In these networks, sensors are randomly deployed in bulk inorder to ensure perfect connectivity and coverage. We propose analgorithm to discover which sensors are to be switched off, withoutmodification of the topology, in order to reduce energy consumption.Our reduction algorithm can be applied to any type of simplicialcomplex and reaches an optimal solution.In a second part, we consider a damaged wireless network, presentingcoverage holes or disconnected components, wepropose a disaster recovery algorithm repairing the network. Itprovides the list of locations where to put new nodes topatch the coverage holes and mend the disconnected components. Inorder to do this we first consider the simplicial complexrepresentation of the network, then the algorithm adds supplementarynodes in excessive number, and afterwards runs the reduction algorithmin order to reach a unimprovable result. We use a determinantal pointprocess for the addition of nodes: the Ginibre point process which hasinherent repulsion between vertices.
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Date:15/10/2014, 14h
Room:LINCS, Salle du Conseil
Speaker:Leonardo Linguaglossa (Alcatel Lucent Bell Labs)
Talk:Caesar: a content router for high-speed forwarding on content names.
Abstract:Today, Internet users are mostly interested to consume content, information and services independently from the servers where these are located.Information Centric Networking (ICN) is a recent networking vein which proposes to enrich the network layer with name-based forwarding, a novel communication primitive centered around content identifiers rather than their location.Despite several name-based forwarding strategies have been proposed, few have attempted to build a content router. Our work fills such gap by designing and prototyping Caesar, a content router for high-speed forwarding on content names.Caesar has several innovative features: (i) a longest prefix matching algorithm that efficiently supports content names, (ii) an incremental design which allows for easy integration with existing network equipments, (iii) support for packet processing offload to graphics processing units (GPUs), and (iv) a forwarding engine distributed across multiple line cards. We build Caesar as a small scale router, and show that it sustains up to 10 Gbps links and over 10 million content prefixes.In addition, GPU offload further speeds up the forwarding rate by an order of magnitude, while distributed forwarding augments the amount of content prefixes served linearly with the number of line cards, with a small penalty in terms of packet processing latency.The full design of a content router also includes a Pending Interest Table and a Content Store. The former is a data-structure used to store pending requests not served yet, while the latter is a packet-level cache used to temporary store forwarded data to serve future requests.We will discuss current and future work on the integration of Pending Interest Table and Content Store in our content router.
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Date:10/10/2014, 15h
Room:Amphi Saphir
Speaker:Fabien Gandon (INRIA)
Talk:Bridging formal semantics and social semantics on the Web
Abstract:The Web became a virtual place where persons and software interact in hybrid communities. These large scale interactions create many problems in particular the one of reconciling formal semantics of computer science (e.g. logics, ontologies, typing systems, etc.) on which the Web architecture is built, with soft semantics of people (e.g. posts, tags, status, etc.) on which the Web content is built. The Wimmics research lab studies methods, models and algorithms to bridge formal semantics and social semantics on the Web. We address this problem focusing on typed graphs formalisms to model and capture these different pieces of knowledge and hybrid operators to process them jointly. This talk will present some of our results and their applications in several projects.
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Date:08/10/2014, 14h00 - 14h30
Room:LINCS, Salle du Conseil
Speaker:Filippo Rebecchi (LIP6-UPMC/Thales)
Talk:DROiD: Adapting to Individual Mobility Pays Off in Mobile Data Offloading
Abstract:Cellular operators count on the potentials of offloading techniques to relieve their overloaded data channels. Beyond standard access point-based offloading strategies, a promising alternative is to exploit opportunistic direct communication links between mobile devices. Nevertheless, achieving efficient device-to-device offloading is challenging, as communication opportunities are, by nature, dependent on individual mobility patterns. We propose, design, and evaluate DROiD (Derivative Re-injection to Offload Data), an original method to finely control the distribution of popular contents throughout a mobile network. The idea is to use the infrastructure resources as seldom as possible. To this end, DROiD injects copies through the infrastructure only when needed: (i) at the beginning, in order to trigger the dissemination, (ii) if the evolution of the opportunistic dissemination is below some expected pace, and (iii) when the delivery delay is about to expire, in order to guarantee 100% diffusion. Our strategy is particularly effective in highly dynamic scenarios, where sudden creation and dissolution of clusters of mobile nodes prevent contents to diffuse properly. We assess the performance of DROiD by simulating a traffic information service on a realistic large-scale vehicular dataset composed of more than 10,000 nodes.DROiD substantially outperforms other offloading strategies, saving more than 50% of the infrastructure traffic even in the case of tight delivery delay constraints. DROiD allows terminal-to-terminal offloading of data with very short maximum reception delay, in the order of minutes, which is a realistic bound for cellular user acceptance.
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Date:08/10/2014, 14h30 - 15h00
Room:LINCS, Salle du Conseil
Speaker:Claudio Imbrenda (Telecom ParisTech/Orange)
Talk:Analyzing Cacheable Traffic in ISP Access Networks for Micro CDN Applications via Content-Centric Networking
Abstract:Web content coming from outside the ISP is today skyrocketing, causing significant additional infrastructure costs to network operators. The reduced marginal revenues left to ISPs, whose business is almost entirely based on declining flat rate subscriptions, call for significant innovation within the network infrastructure, to support new service delivery.In this paper, we suggest the use of micro CDNs in ISP access and back-haul networks to reduce redundant web traffic within the ISP infrastructure while improving user's QoS.With micro CDN we refer to a content delivery system composed of (i) a high speed caching substrate, (ii) a content based routing protocol and (iii) a set of data transfer mechanisms made available by content-centric networking.The contribution of this paper is twofold. First, we extensively analyze more than one month of web traffic via continuous monitoring between the access and back-haul network of Orange in France. Second, we characterize key properties of monitored traffic, such as content popularity and request cacheability, to infer potential traffic reduction enabled by the introduction of micro CDNs.Based on these findings, we then perform micro CDN dimensioning in terms of memory requirements and provide guidelines on design choices.
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Date:18/09/2014, 14h
Room:Rue Barrault, Amphi Opale
Speaker:Anne Etien (LIFL/Equipe projet INRIA Rmod)
Talk:Maintenance et Evolution des logiciels
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Date:17/09/2014, 14h
Room:LINCS, Salle du Conseil
Speaker:Emilio Leonardi (Politecnico di Torino)
Talk:A unified approach to the performanceanalysis of caching systems
Abstract:We propose a unified methodology to analyse theperformance of caches (both isolated and interconnected), byextending and generalizing a decoupling technique originally knownas Che's approximation, which provides very accurate results at lowcomputational cost.We consider several caching policies, taking intoaccount the effects of temporal locality. In the case of interconnectedcaches, our approach allows us to do better than the Poissonapproximation commonly adopted in prior work. Our results,validated against simulations and trace-driven experiments, provideinteresting insights into the performance of caching systems. Joint work with Valentina Martina and Michele Garetto, appeared at IEEE INFOCOM'14
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Date:10/09/2014, 14h
Room:LINCS, Salle du Conseil
Speaker:Cheng Wang (Pennsylvania State University)
Talk:Energy management of demand in the cloud
Abstract:We formulate optimization problems to study how data centers might modulate their power demands for cost-effective operation taking into account various complexities exhibited by real-world electricity pricing schemes. For computational tractability reasons, we work with a fluid model for power demands which we imagine can be modulated using two abstract knobs of demand dropping and demand delaying (each with its associated penalties or costs). We consider both stochastically known and completely unknown inputs, which are likely to capture different data center scenarios. Using empirical evaluation with both real-world and synthetic power demands and real-world prices, we demonstrate the efficacy of our techniques. Work in collaboration with B. Urgaonkar, G. Kesidis, U. Shanbhag, Q. Wang, A. Sivasbramaniam
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Date:16/07/2014, 14h
Room:LINCS, Salle du Conseil
Speaker:Sameh Benfredj (Telecom ParisTech/Alcatel Lucent Bell Labs)
Talk:Semantic-based IoT service discovery mechanism for dynamic environments
Abstract:The adoption of Service Oriented Architecture (SOA) and semantic Web technologies in the Internet of Things (IoT) enables to enhance the interoperability of devices by abstracting their capabilities as services and to enrich their descriptions with machine-interpretable semantics. This facilitates the discovery and composition of IoT services. The increasing number of IoT services, their dynamicity and geographical distribution require mechanisms to enable scalable and efficient discovery. We propose, in this paper, a semantic based IoT service discovery system that supports and adapts to the dynamicity of IoT services. The discovery is distributed over a hierarchy of semantic gateways. Within a semantic gateway, we implement mechanisms to dynamically organize its content over time, inorder to minimize the discovery cost. Results show that our approach enables to maintain a scalable and efficient discoveryand limits the number of updates sent to a neighboring gateway.
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Date:09/07/2014, 14h
Room:LINCS, Salle du Conseil
Speaker:Olivier Marce (Alcatel Lucent Bell Labs)
Talk:Tout ce que vous aimerez avoir su sur la 5G quand elle existera
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Date:04/07/2014, 15h
Room:Rue Barrault, room E200
Speaker:Prof. Dr.-Ing. C. M�ller-Schloer
Talk:Organic Computing: Adaptivity and Self-organization at Runtime
Abstract:Organic Computing has emerged almost 10 years ago as a challenging vision for future in-formation processing systems, based on the insight that already in the near future we will be surrounded by large collections of autonomous systems equipped with sensors and actuators to be aware of their environment, to communicate freely, and to organize themselves. The presence of networks of intelligent systems in our environment opens fascinating application areas but, at the same time, bears the problem of their controllability. Hence, we have to construct these systems - which we increasingly depend on - as robust, safe, flexible, and trustworthy as possible. In order to achieve these goals, our technical systems will have to act more independently, flexibly, and autonomously, i.e. they will have to exhibit life-like properties. We call those systems organic. Hence, an Organic Computing System is a technical system, which adapts dynamically to the current conditions of its environment. It will be self-organizing, self-configuring, self-healing, self-protecting, self-explaining, and context-aware.First steps towards adaptive and self-organizing computer systems have already been undertaken. Adaptivity, reconfigurability, emergence of new properties, and self-organisation are topics in a variety of research projects. From 2005 until 2011 the German Science Foundation (DFG) has funded a priority research program on Organic Computing. It has addressed fundamental challenges in the design of complex computing systems; its objective was a deeper understanding of emergent global behaviour in self-organising systems and the design of specific concepts and tools to support the construction of Organic Computing systems for technical applications.This presentation will briefly recapitulate the basic motivation for Organic Computing, explain key concepts, and illustrate these concepts with some project examples. We will then look into possible future directions of OC research concentrating on (1) Online optimization and (2) Social Organic Computing.
Biography:Christian M�ller-Schloer studied EE at the Technical University of Munich and received the Diploma degree in 1975, the Ph. D. in semiconductor physics in 1977. In the same year he joined Siemens Corporate Technology where he worked in a variety of research fields, among them CAD for communication systems, cryptography, simulation accelerators and RISC architectures.From 1980 until 1982 he was a member of the Siemens research labs in Princeton, NJ, U.S.A. In 1991 he was appointed full professor of computer architecture and operating systems at the University of Hannover. His institute, later renamed to Institute of Systems Engineering
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Date:02/07/2014, 14h
Room:LINCS, Salle du Conseil
Speaker:Arvind Krishnamurthy (University of Washington)
Talk:Approximately Synchronous Distributed Systems
Abstract:Applications hosted within the datacenter often rely on distributedservices such as Zookeeper, Chubby, and Spanner for fault-tolerantstorage, distributed coordination, and transaction support. Thesesystems provide consistency and availability in the presence oflimited failures by relying on sophisticated distributed algorithmssuch as state machine replication. Unfortunately, these distributedalgorithms are expensive, accrue additional latency, suffer frombottlenecks, and are difficult to optimize. This state of affairs isdue to the fact that distributed systems are traditionally designedindependently from the underlying network and supporting protocols,making worst-case assumptions (e.g., complete asynchrony) about itsbehavior.While this is reasonable for wide-area networks, many distributedapplications are however deployed in datacenters, where the network ismore reliable, predictable, and extensible. Our position is thatcodesigning networks and distributed systems in order to operate underan "approximately synchronous" execution model can have substantialbenefits in datacenter settings. We will illustrate this using twocase studies in this talk: Speculative Paxos -- a distributedcoordination service for datacenters that relies on the network toexhibit approximately synchronous behavior in the normal case, whilestill remaining correct if the network exhibits weaker properties, andOptimistic Replicated Two-Phase Commit (OR-2PC) -- a new distributedtransaction protocol that uses a new optimistic ordering technique,based on loosely synchronized clocks in order to improve boththroughput and latency.
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Date:25/06/2014, 15h-16h
Room:LINCS, Salle du Conseil
Speaker:Don Towsely (University of Massachusetts, Amherst)
Talk:Randomness, Everlasting Security, and Undetectability
Abstract:Security and privacy are fundamental concerns in today's world. These concerns have become particularly prominent with Snowden's revelationsof the presence of the NSA in our daily lives. These revelations haveshown that traditional cryptographic techniques do not provide as was expected. This has called into question how security and privacy can be provided. In this talk we investigate how randomness in the environment can be used to provide everlasting security and undetectability(privacy) in wireless communications. In the first part of the talk we describe a practical way to harness this randomness to provide and improve the security of wireless communications. We introduce the notion of "dynamic secrets", information shared by two parties, Alice and Bob, engaged in communication and not available to an adversary, Eve. The basic idea is to dynamically generate a series of secrets from randomness present in the in wireless environment. These dynamic secrets exhibit interesting security properties and offer a robust alternative to cryptographic security protocols. We present a simple algorithm for generating these secrets and using them to ensure secrecy.In some situations, Alice and Bob may want not only to secure their communications but to keep it private. In the second part of our talk we focus on the use of randomness to conceal the communications. Here the challenge is for Alice to communicate with Bob without an adversary, Willie the warden, ever realizing that the communication is taking place. Specifically, we establish that Alice can send O(t) bits (and no more) to Bob in time t over a variety of wireless and optical channels. Moreover, we report experimental results that corroborate the theory.
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Date:25/06/2014, 14h-15h
Room:LINCS, Salle du Conseil
Speaker:Lixia Zhang (UCLA)
Talk:The art of packet format design
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Date:20/06/2014, 14h - 15h
Room:Site Barrault, Room C48
Speaker:Nicolas Riche
Talk: Where People Look
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Date:19/06/2014, 14h
Room:LINCS, Salle du Conseil
Speaker:George Iosifidis (CERTH/ITI and University of Thessaly)
Talk:Incentive Mechanisms for User-provided Networks
Abstract:The increasing mobile data demand and the proliferation of advanced handheld devices place the user-provided networks (UPNs) at a conspicuous position in next-generation network architectures. There has been growing consensus that UPNs can play a crucial role both in self-organizing and in operator-controlled wireless networks, as they enable the exploitation of the diverse communication needs and resources of different users. Today, many innovative startups such as Open Garden, M-87, and Karma, as well as major network operators such as Deutsche Telekom, Telefonica, Comcast, and China Mobile Hong Kong, propose or even implement such models. However, in UPNs both the availability and the demand for Internet access rely on user-owned network equipment. Therefore, the success of this type of networks depends on the participation of users. In this talk, we analyze the design challenges of incentive mechanisms for encouraging user engagement in user-provided networks. Motivated by recently launched business models, we focus on mobile UPNs where the energy consumption and data usage costs are critical, and have a large impact on users' decisions both for requesting and offering UPN services. We outline two novel incentive schemes that have been recently proposed for such UPNs, and discuss the open issues that must be further addressed.
Biography:George Iosifidis holds an Engineering Degree in Telecommunications (Greek Air Force Academy, 2000), a M.Sc. and a Ph.D. degree in communication networks (University of Thessaly, 2007 and 2012). Currently, he is a post-doc researcher at CERTH/ITI and University of Thessaly, Volos. His research interests lie at the nexus of network optimization and network economics, with emphasis on spectrum economics, autonomous networks, small cell networks, user-centric networks and mobile data offloading. More information can be found at www.georgeiosifidis.net
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Date:18/06/2014, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Miodrag Jovanovic (INRIA/Orange)
Talk:How user throughput depends on the traffic demand in large cellular networks
Abstract:We assume a space-time Poisson process of call arrivals on the infinite plane, independently marked by data volumes and served by a cellular network modeled by an infinite ergodic point process of base stations. Each point of this point process represents the location of a base station that applies a processor sharing policy to serve users arriving in its vicinity, modeled by the Voronoi cell, possibly perturbed by some random signal propagation effects.Using ergodic arguments and the Palm theoretic formalism, we define a global mean user throughput in the cellular network and prove that it is equal to the ratio of mean traffic demand to the mean number of users in the steady state of the "typical cell" of the network. Here, both means account for double averaging: over time and network geometry, and can be related to the per-surface traffic demand, base-station density and the spatial distribution of the signal-to-interference-and-noise ratio. This latter accounts for network irregularities, shadowing and cell dependence via some cell-load equations.We validate our approach comparing analytical and simulation results for Poisson network model to real-network measurements. Little's law allows expressing the mean user throughput in any region of the network as the ratio of the mean traffic demand to the steady-state mean number of users in this region. Corresponding statistics are usually collected in operational networks for each cell.
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Date:11/06/2014, 11h-12h
Room:LINCS, Salle du Conseil
Speaker:Sergey Foss (Heriot-Watt University, Edinburgh and Institute of Mathematics, Novosibirsk)
Talk:Adaptive transmission protocols for a random multiple access channel
Abstract:There are known two "ALOHA-type" models, (a) with a finite number of queues and with messages ahead of each queue being potentially "active", and (b) without queues and all "active" messages. I'll talk about model (b), introduce a number of new protocols for their stability, and discuss some open problems.
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Date:11/06/2014, 14h
Room:LINCS, Salle du Conseil
Speaker:Dr. Beth Coleman (University of Waterloo, Ontario Canada) and Howard Goldkrand (SapientNitro)
Talk:Smart Cites, Smart things...and Smart Citizens: designing the city as platform
Abstract:This talk asks how can we better design urban environments, leveraging networked technologies to facilitate rich engagement by its inhabitants. It discussed the recent history of Smart City design as a top-down application, the emergence of Civic Hackers, and the effect of ubiquitous computing on Information Communication Technologies.
Biography:Dr. Beth Coleman, director City as Platform Lab (Games Institute), and Co-director Critical Media Lab at the University of Waterloo, Ontario Canada http://www.cityasplatform.org. She is a Faculty Fellow at Berkman Center for Internet & Society, Harvard University. Coleman works with new technology and art to create transmedia forms of engagement. Her research addresses issues of network society, subjectivity, and the contemporary city, as well as philosophy of technology, critical race studies, and media design. She is the co-founder of SoundLab Cultural Alchemy, an internationally acclaimed multimedia performance platform. As an artist, she has a history of international exhibition including venues such as the Whitney Museum of American Art, New Museum of Contemporary Art, and Mus�e d'Art moderne Paris. She has worked with research consortiums that involve academic, industry and arts collaborators. She is a founding member of the Microsoft Research Fellow Social Media Collective and an expert consultant for the European Union Digital Futures Initiative. Her work has been presented as part of the TEDx East conference, on National Public Radio, and reviewed in The Guardian (UK) and Washington Post newspapers.She works internationally with collaborators in Africa, Europe, and Asia. Her book Hello Avatar is published by the MIT Press and was recently translated into Turkish.Howard Goldkrand is an artist and innovations director who works on transmedia design, immersive engagement, and networked media strategy across industries. He is Head of Innvation Design for the global digital media creative agency SapientNitro (http://www.sapient.com/en-us/sapientnitro.html). In his recent work history, Goldkrand has been executive producer of a future of storytelling project for Cond� Nastu2019s Ideactive. He was Innovations Director and Cultural Engineer at Modernista! where he lead the team for the Alternate Reality Game for the Dexter TV show (Showtime) for which he won a Webby award, best marketing piece at ComicCon, and nominated for an Emmy Award. He also led the work on TOMS with the launch of their eyewear product and continues to do innovation work for the company. From the perspective of strategy, creative, media, production and innovations, he has worked with clients that include GM, TIAA-CREF, Palm, Napster, Food Should Taste Good, Product(RED),TOMS, Nickelodeon, HTC, NIKE, Starbucks, SCION, Samsung. He continues to work with Neverstop, a group out of Seattle founded by Alex Calderwood of Ace Hotel fame. As an artist, he began an experimental studio practice at Wesleyan University, creating conceptual work that spanned sculpture and performance. He is the codirector of SoundLab Cultural Alchemy, an experimental electronic music and art platform. He has had a long international art career exhibiting at venues such as PS 1 MOMA, Chinati Foundation, Marfa, Texas, Recollets, Paris, Art Museum of Vancouver, Castil de Rivoli, Turin Italy, and the WAAG Society Amsterdam. Goldkrand speaks internationally at workshops, panels, and conferences on art and culture.
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Date:11/06/2014, 15h30-16h30
Room:LINCS, Salle du Conseil
Speaker:Venkat Anantharam (University of California, Berkeley)
Talk:Convex relative entropy decay in Markov chains
Abstract:Consider an irreducible continuous time Markov chain with a finite or a countably infinite number of states and admitting a unique stationary probability distribution. The relative entropy of the distribution of the chain at any time with respect to the stationary distribution is a monotonically decreasing function of time. It is interesting to ask if this function is convex. We discuss this question for finite Markov chains and for Jackson networks, which are a class of countable state Markov chains of interest in modeling networks of queues. (Joint work with Varun Jog.)
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Date:14/05/2014, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Thomas Bonald (Telecom ParisTech)
Talk:Application of queuing theory to traffic engineering
Abstract:Traffic engineering refers to the set of techniques used to dimension links and route traffic in IP networks. It relies most often on simplistic traffic models where packets arrive according to a Poisson process at each router, independently of the experienced delays and losses. In this talk, we revisit traffic engineering methods in the light of more realistic traffic models where data transfers are viewed as fluid flows sharing links in an elastic way, mimicking the congestion control algorithms of TCP. The corresponding queuing system is no longer a set of independent FIFO queues but a set of coupled processor-sharing queues. We show that minimizing the mean delay in this system tends to balance load more equally in the network.
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Date:07/05/2014, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Izhak Rubin (UCLA)
Talk:Relay aided Communications Networking for Power Line and Vehicular System
Abstract:We consider a smart grid based power-line communications network (PCN) which serves stations that represent subscriber devices and/or power company employed sensor nodes. The network is managed by a control (gateway) station that is attached to a power line and acts to supervise and control the sharing of the PCN medium by stations attached to the line. The gateway receives periodic updates from the stations, and collects data flows that are triggered by those stations that become active due to occurrence of exception events.We design and study a cross-layer adaptive-rate networking mechanism that enables active stations to efficiently transport their message flows to the gateway. Our approach is based on the selection of certain stations to act as relay nodes (RNs), during certain transmission time phases. A scheduling protocol is derived, and its parameters optimized, in a manner that properly regulates transmissions by active stations and by relay nodes, in aiming to achieve high spatial reuse levels that induce high throughput rates while maintaining low message delays and low nodal energy consumption levels.As a second topic, we will outline our latest results involving our new Vehicular Backbone Network (VBN) method for the design of a Vehicular Ad hoc Network (VANET). We derive an effective configuration of the network to attain high throughput and low delay performance behavior for multicasting message flows issued by a road side unit. The integration of such operation with cellular and WiFi systems is also invoked.
Biography:Izhak Rubin received the B.Sc. and M.Sc. from the Technion - Israel Institute of Technology, Haifa, Israel, and the Ph.D. degree from Princeton University, Princeton, NJ, all in Electrical Engineering. Since 1970, he has been on the faculty of the UCLA School of Engineering and Applied Science where he is currently a Distinguished Professor in the Electrical Engineering Department.Dr. Rubin has had extensive research, publications, consulting, and industrial experience in the design and analysis of commercial and military computer communications and telecommunications systems and networks. Such design and analysis projects include network systems employed by the FAA for air traffic control, terrestrial and satellite based mobile wireless networks, high speed multimedia telecommunications networks, advanced cellular cross-layer operations, mobile backbone ad hoc wireless networks, mechanisms to assure network resiliency and automatic failover operations. At UCLA, he is leading a research group in the areas of telecommunications and computer communications networks. He serves as co-director of the UCLA Public Safety Network Systems Laboratory.During 1979-1980, he served as Acting Chief Scientist of the Xerox Telecommunications Network. He served as co-chairman of the 1981 IEEE International Symposium on Information Theory; as program chairman of the 1984 NSF-UCLA workshop on Personal Communications; as program chairman for the 1987 IEEE INFOCOM conference; and as program co-chair of the IEEE 1993 workshop on Local and Metropolitan Area networks, as program co-chair of the 2002 first UCLA/ONR Symposium on Autonomous Intelligent Networked Systems (AINS), and has organized many other conferences and workshops. He has served as an editor of the IEEE Transactions on Communications, Wireless Networks journal, Optical Networks magazine, IEEE JSAC issue on MAC techniques, Communications Systems journal, Photonic Networks Communications journal, and has contributed chapters to texts and encyclopedia on telecommunications systems and networks. Dr. Rubin is a Life Fellow of IEEE.
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Date:30/04/2014, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Uri Yechiali (Tel-Aviv University)
Talk:Tandem Jackson Networks, Asymmetric Inclusion Processes and Catalan Numbers
Abstract:The Tandem Jackson Networkis a system of n sites (queues)in series, where single particles (customers, jobs, packets, etc.) move, one by one anduni-directionally,from one site to the next until they leave the system. (Think, for example, on aproduction line, or on a line in a cafeteria).When each site is a M/M/1 queue, the Tandem Jackson Network is famous for its product-form solution of the multi-dimensional Probability Generating Function of the site occupancies. In contrast, the Asymmetric Inclusion Process (ASIP) is a series of n Markovian queues (sites), each with unbounded capacity, but with unlimited-size batch service. That is, when service is completed at sitek,all particles present there move simultaneously to sitek+1,and form a cluster with the particles present in the latter site. We analyze the ASIP and show that its multi-dimensional Probability Generating Function(PGF) does notposses a product-form solution. We then present a method to calculate this PGF. We further show that homogeneous systems are �optimal� and derive limit laws (when the number of sites becomes large) for various variables (e.g. busy period, draining time, etc.). Considering the occupancies of the sites (queue sizes) we show that occupation probabilities in the ASIP obey a discrete two-dimensional boundary value problem. Solving this problem wefind explicit expressions for the probability that site k is occupied by m particles (m=0,1,2,..).Catalan's numbersare shown to naturally arise in the context of these occupation probabilities. This is a joint work with ShlomiReuveni and IddoEiazar.
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Date:23/04/2014, 14h - 15h
Room:LINCS, Salle de Conseil
Speaker:DaeYoung Kim (CNU)
Talk:Some Thoughts on Loc/ID Separation
Abstract:Locator(Loc)/identifier(ID) Separation(LIS) was conceived to mitigate the explosion of the DFZ routing table. To be literally exact, every host would be given a Loc in addition to an ID. The talk asserts that provision of Locs in this fashion does not help combat the problem at all; it would only inherit the same fate with the current IP address.What would really help would be use of two-tier Locs, with one set local to a site and another globally relevant. That is to day, use of local addressing(Loc) would be the only exit. Some LIS proposals like ILNP and LISP achieve this by their own tricky definition of Locs. The talk asserts what they really implement is adoption of local addressing, rather than LIS.In LISP, EID(endpoint ID) is also used for routing within a site, thus is semantically overloaded in the same way as IP address is. This also implies semantic overloading isn't the real problem from the start, thus there'd be no rationale for LIS. Semantic overloading (for both identification and location) of an address is rather an intrinsic nature of networking. What people really need is local addressing.If time permits, the talk also would suggest use of ISIS to make the best use of EID in LISP.
Biography:DY is a professor of CNU(Chungnam National University) in South Corea, in the department of Information Communications Engineering, since 1983. He got a bachelor degree from SNU(Seoul National University) and a MS and a PhD degree, both from KAIST(Korea Advanced Institute of Science and Technology), before joining CNU. He's been working on various fields of networking, with recent focus on Future Internet. He's also been active in standardization and REN(research and educational networking) activities, and is current Chair of ISO/IEC JTC 1/SC 6, where OSI once was made, and Chair of APAN(Asia-Pacific Advanced Network), a non-profit consortium similar to Internet 2 (US) and Terena (EU).
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Date:10/04/2014, 15h-16h
Room:Salle C46, rue Barrault
Speaker:Janos Korner (U. la Sapienza)
Talk:From Shannon to Infinity
Biography:Janos Korner has been a Professor in Computer Science at "Sapienza" University of Rome since 1993. He obtained his Degree in Mathematics in 1970. From 1970 to 1992 he worked at the Mathematical Institute of the Hungarian Academy of Sciences. During these years he had two periods of leave: from 1981 to 1983 working at Bell Laboratories, Murray Hill, NJ, and for the academic year 1987-88 working at ENST, Paris, France. He is an Associate Editor of IEEE Trans. Information Theory. In 2010 he was elected to the Hungarian Academy of Sciences as an External Member. He received the Claude Shannon Award of the IEEE Information Theory Society for 2014.
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Date:09/04/2014, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Petr Kuznetsov (Telecom ParisTech)
Talk:The Case for Reliable Software Transactional Networking
Abstract:Software-defined networking (SDN) is a novel paradigm that outsources the control of packet-forwarding switches to a set of software controllers. The most fundamental task of these controllers is the correct implementation of the network policy, i.e., the intended network behavior. In essence, such a policy specifies the rules by which packets must be forwarded across the network. We initiate the study of the SDN control plane as a distributed system.We introduce a formal model describing the interaction between the data plane and a distributed control plane (consisting of a collection of fault-prone controllers). Then we formulate the problem of consistent composition of concurrent network policy updates. The composition is enabled via a transactional interface with all-or-nothing semantics, which allows us to reason about possibilities and impossibilities in controller synchronization.
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Date:08/04/2014, 10am
Room:LINCS, Salle du Conseil
Speaker:Patricio Reyes (Universidad Carlos III de Madrid)
Talk:Towards Detecting Influential Individuals in Social Networks
Abstract:I discuss the problem of detecting influential individuals in social networks. Viral marketing campaigns seek to recruit a small number of influential individuals who are able to cover the largest target audience. Most of the literature assumes the networkis known, but usually there is no information about the topology. I present models where topology is usually unknown at first, but gradually it is discovered thanks to the local information provided by the recruited members. I show preliminary results (simulations)obtained by the analysis of algorithms based on different levels of local information. (Joint work with Alonso Silva
Biography:Patricio Reyes holds a B.Sc. in Mathematics (2000) and a M.Sc. in Mathematical Engineering (2003) from the University of Chile. He got his Ph.D. in Computer Science (2009) working atthe French National Institute for Research in Computer Science and Control, INRIA. He has worked as an associate researcher at CMM, the Chilean Centre for Mathematical Modelling (research unit of CNRS, France) and the Mine Planning Lab at the University ofChile. At present, he is a postdoctoral visitor in the Department of Statistics at Universidad Carlos III de Madrid since 2012.His main research interests are: social network analysis; data-gathering algorithms in networks; routing & scheduling in wireless mesh networks; mine planning.
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Date:02/04/2014, 14h30
Room:LINCS, Salle de Conseil
Speaker:Stephane Wustner (Technicolor)
Talk:Characterizing bufferbloat from end-hosts
Abstract:While, on routers and gateways, buffers on forwarding devices are required to handle bursty Internet traffic, overly large or badly sized buffers can interact with TCP in undesirable ways. This phenomenon is well understood and is often called bufferbloat. Although a number of previous studies have shown that buffering (particularly, in home) can delay packets by as much as a few seconds in the worst case, there is less empirical evidence of tangible impacts on end-users. In this paper, we develop a modified algorithm that can detect bufferbloat at individual end-hosts based on passive observations of traffic. We then apply this algorithm on packet traces collected at 55 end- hosts, and across different network environments. Our results show that 45 out of the 55 users we study experience bufferbloat at least once, 40% of these users experience bufferbloat more than once per hour. In 90% of cases, buffering more than doubles RTTs, but RTTs during bufferbloat are rarely over one second. We also show that web and interactive applications, which are particularly sensitive to delay, are the applications most often affected by bufferbloat.
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Date:02/04/2014, 14h00
Room:LINCS, Salle de Conseil
Speaker:Giuseppe Scavo (Alcatel Lucent Bell Labs and INRIA)
Talk:Gold mining in a River of Internet Content Traffic
Abstract:With the advent of Over-The-Top content providers(OTTs), Internet Service Providers (ISPs) saw their portfolio ofservices shrink to the low margin role of data transporters. Inorder to counter this effect, some ISPs started to follow big OTTslike Facebook and Google in trying to turn their data into avaluable asset. In this paper, we explore the questions of whatmeaningful information can be extracted from network data, andwhat interesting insights it can provide. To this end, we tacklethe first challenge of detecting user-URLs, i.e., those links thatwere clicked by users as opposed to those objects automaticallydownloaded by browsers and applications. We devise algorithmsto pinpoint such URLs, and validate them on manually collectedground truth traces. We then apply them on a three-day longtraffic trace spanning more than 19,000 residential users thatgenerated around 190 million HTTP transactions. We find thatonly 1.6% of these observed URLs were actually clicked by users.As a first application for our methods, we answer the questionof which platforms participate most in promoting the Internetcontent. Surprisingly, we find that, despite its notoriety, only 11%of the user URL visits are coming from Google Search.
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Date:26/03/2014, 14h - 15h
Room:LINCS salle de conseil
Speaker:Salaheddine Elayoubi (Orange)
Talk:Making mobile access networks green: from research to standardization
Abstract:Energy efficiency in mobile networks is gaining in importance from both environmental and business points of view. In particular, site sleep mode techniques are being introduced along with self organizing procedures that enable a dynamic activation/deactivation of sites without compromising Quality of Service (QoS). As the research is progressively broadening towards increased energy efficiency, green concepts are being introduced in standardization. For instance, 3GPP and ETSI are introducing energy efficiency enablers within their mobile networks standards. This talk gives an overview on the latest theoretical advances in optimal control for energy efficiency in mobile networks and the related standardization activities.
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Date:20/03/2014, 14h
Room:LINCS salle de conseil
Speaker:Zaheer Khan (University of Oulu, Finland)
Talk:Opportunistic Channel Selection by Cognitive Radios Under Imperfect Observations and Limited Memory: A Repeated Game Model
Abstract:To help mitigate the critical stress on spectrum resources spurred by the more powerful and the more capable smart devices, a recent presidential advisory committee report and also a FCC report recommend the use of spectrum sharing technologies. One such technology addressed in these reports iscognitive radio (CR), in which a network entity is able to adapt intelligently to the environment throughobservation, exploration and learning.In this talk, we discuss the problem of coexistence, competition and fairness among autonomous cognitive Radios (CRs) in multiple potentially available channels that may be non-homogeneous in terms of primary user (PU) occupancy. Moreover, the real spectrum occupancy data collected at RWTH Aachen confirms that the spectrum resources are in general non-homogeneous in terms of PU occupancy. We present a model in which a CR that is able to adapt to the environment through observation and exploration is limited in two ways. First, as in practical CR networks, CRs have imperfect observations (such as due to sensing and channel errors) of their environment. Second, CRs have imperfect memory due to limitations in computational capabilities. For efficient opportunistic channel selection, we discuss efficient strategies and utilize the framework of repeated games (with imperfect observations and memory) to analyze their stability in the presence of selfish deviations.
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Date:19/03/2014, 14h
Room:LINCS salle de conseil
Speaker:Adel Sohbi (Telecom ParisTech)
Talk:Quantum Information
Abstract:Information is something encoded in physical systems's properties. Hence the study of information and computation is linked to the underlying physical processes. Quantum Information is the study of information encoded in the state of quantum system. Quantum phenomena such as the superposition principle and entanglement give rise to a other approach and opportunities in all the sub-fields of Information Theory. The goal of this seminar, by giving some basic concepts of quantum information, is to give a very naive approach which will permit to the audiance to have an overview of the Quantum Information field.
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Date:12/03/2014, 14h - 15h
Room:LINCS salle de conseil
Speaker:Yves Vanaubel (Universite' de Liege)
Talk:Network Fingerprinting: TTL-Based Router Signatures
Abstract:Fingerprinting networking equipment has many potential applications and benefits in network management and security. More generally, it is useful for the understanding of network structures and their behaviors. In this paper, we describe a simple fingerprinting mechanism based on the initial TTL values used by routers to reply to various probing messages. We show that main classes obtained using this simple mechanism are meaningful to distinguish routers platforms. Besides, it comes at a very low additional cost compared to standardactive topology discovery measurements. As a proof of concept, we apply our method to gain more insight on the behavior of MPLS routers and to, thus, more accurately quantify their visible/invisible deployment.This work has been published in IMC 2013.
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Date:05/03/2014, 14h
Room:LINCS salle de conseil
Speaker:Remi Varloot (ENS)
Talk:On the resiliency of the French Internet
Abstract:This presentation focuses on the resiliency of the French Internet, studied from thepoint of view of network interconnectivity. We define a model for representing theBGP-level topology of the Internet which takes into account the businessrelationships between ASes, and implement an algorithm to construct such a map frompublicly available routing information.The portion of the Internet responsible for the connectivity of French ASes is thenestablished, and the risk of disconnection is assessed. To this end, we identify aset of critical ASes whose suppression would disconnect other ASes from theInternet.Finally, we give some insight as to how the model could be expanded and thedifficulties this would introduce. We also give an example of how a BGP-level map ofthe Internet can be used to actively monitor the network.TBD
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Date:26/02/2014, 14h00 - 14h30
Room:LINCS, Salle du Conseil
Speaker:Karel De Vogeleer (Telecom ParisTech)
Talk:Energy-Aware Computing with Application Processors
Abstract:Energy aware computing is as ubiquitous as ubiquitous computing itself. The user experience and up-time of hand-held devices are affected directly by the squander of battery resources. We will focus on embedded systems, e.g., smartphones, or tables, and highlight the most prominent sources of power consumption in application processors. The temperature dependency of the power consumption is also discussed. This implies the importance of thermal models for passively cooled devices, used by DVFS controllers, process schedulers, and thermal management units. Passively cooled devices show substantially different thermal behavior compared to actively cooled devices. Our latest developments on this topic are briefly presented. Furthermore, common energy optimization techniques, both software and hardware based, are discussed. The referenced material covers practical, industrial and academic solutions to the energy optimization problem.
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Date:26/02/2014, 14h30 - 15h00
Room:LINCS, Salle du Conseil
Speaker:Nihel Djoher Benzaoui (Alcatel-Lucent)
Talk:Impact of the electronic architecture of optical slot switching nodes on latency in ring networks
Abstract:An optical slot switching node network called POADM (packet optical add-drop multiplexers) has formerly been proposed as a flexible solution for metropolitan ring networks to carry data traffic with a sub-wavelength switching granularity and with a good energy efficiency, which is enabledby optical transparency. In this paper, for the first time we propose several architectures for the electronic side of optical slot switching nodes to increase flexibility through the addition of electronic switches, working either at client packet granularity or at slot granularity; such electronic switches can be locatedat either transmitter, receiver, or both sides of a node, thereby decreasing traffic latency, at the expense of increased node cost and/or energy consumption. This paper focuses on the latency aspect. We investigate the impact of a timer that can be used to upper bound the slots insertion time on the medium. We also propose, for the first time, a queuing model for optical slot switching ring and assess and compare the latency of these node architectures analytically using queuing theory, and with simulations.
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Date:19/02/2014, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Steve Uhlig (Queen Mary University, London)
Talk:Optimal cache allocation for content-centric networking
Abstract:Content-Centric Networking (CCN) is a promising framework for evolving the current network architecture,advocating ubiquitous in-network caching to enhance contentdelivery. Consequently, in CCN, each router has storage spaceto cache frequently requested content. In this work, we focuson the cache allocation problem: namely, how to distribute thecache capacity across routers under a constrained total storagebudget for the network. We formulate this problem as a contentplacement problem and obtain the exact optimal solution by atwo-step method. Through simulations, we use this algorithm toinvestigate the factors that affect the optimal cache allocationin CCN, such as the network topology and the popularity ofcontent. We find that a highly heterogeneous topology tends toput most of the capacity over a few central nodes. On the otherhand, heterogeneous content popularity has the opposite effect, byspreading capacity across far more nodes. Using our findings, wemake observations on how network operators could best deployCCN caches capacity
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Date:05/02/2014, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:James Roberts (IRT-SystemX)
Talk:Be fair to flows: a fair network is attractive and trustworthy and far more than just adequate
Abstract:The subject of active queue management is again highly topical with the recent creation of a new IETF working group. Regained interest has arisen notably from the observed failings of traditional approaches to congestion control in environments as diverse as the data center interconnect and the home network subject to "bufferbloat". In this context it is opportune to remake the case for implementing per-flow fair queueing as the standard packet scheduling algorithm in router buffers. Though flow fairness as the basis of congestion control was proposed by Nagle as early as 1985 and feasibility was demonstrated at least 15 years ago in Bell Labs work on PacketStar, the networking research community has largely remained focused on designing new TCP versions and AQM algorithms as if the FIFO buffer were an unavoidable technological constraint. We show how per-flow fairness realizes implicit service differentiation and greatly facilitates network engineering with the notion of "fair networks" appearing as a natural parallel to that of "loss networks". Accounting for the stochastic nature of traffic, simple fairness is generally seen to be preferable to weighted fairness or size-based priority scheduling while longest queue drop is likely the only AQM required.
Biography:Jim Roberts very recently joined the French research institute IRT-SystemX to work on a project on Cloud computing and network architecture. He was previously with Inria from September 2009 after spending more than thirty years with France Telecom research labs. He received a degree in Mathematics from the University of Surrey in 1970 and a doctorate in computer science in 1987 from the University of Paris VI. His research is centered on the performance evaluation and design of traffic controls for communication networks. In a long career, he has published around 100 papers, chaired several program committees and been associate editor for a number of journals. He gave the Keynote at Infocom 2013. He is a Fellow of the Societe des Electriciens et Electroniciens (SEE) and recipient of the Arne Jensen lifetime achievement award from the International Teletraffic Congress (ITC).
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Date:29/01/2014, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Jim Kurose (University of Massachusetts Amherst)
Talk:Protecting Privacy While Providing Utility in Published Network Mobility Traces Using Differential Privacy
Abstract:Those who design, develop and deploy computer and networked systems, have a vital interest in how these systems perform in "real-world" scenarios. But real-world conditions and data sets are often hard to come by-companies treat scenario data as a confidential asset and public institutions are reluctant to release data for fear of compromising individual privacy. This challenge is particularly acute in mobile wireless networks, where many have noted the need for realistic mobility and wireless network datasets. But assuring privacy is difficult. Several well-known examples have shown how anonymized data sets can be combined with other data to compromise individuals' personal privacy. The relatively recent model of differential privacy (DP) provides an alternate approach to measuring and controlling the disclosure of personal information, adding sufficient random "noise" (in a precisely quantifiable manner) to any output computed from a sensitive collection of data, so that a precise statistical privacy condition is met. In this talk we outline ongoing research to produce trajectory traces, and results derived from trajectory traces, for public release from original "real-world" mobility traces (e.g., from our 802.11 campus network) while providing both well-defined differential privacy guarantees and demonstrably high accuracy when these publicly-released data sets are used for a number of common network and protocol design and analysis tasks. We describe a DP technique using a constrained trajectory-prefix representationof the original data, using known network topology and human mobility constraints, to determinethe underlying representation of the original data and judiciously allocate random noise needed tosatisfy DP constraints. We will also discuss alternative representations of mobility data that we conjecture will provide better accuracy for specific analysis tasks, and discuss the tradeoff between generality/specificity and accuracy.This is a "work-in-progress" talk, so ideas are still being "baked" and comments/discussion are particularly welcome. This is joint research with Gerome Miklau and Jennie Steshenko at the University of Massachusetts Amherst
Biography:Jim Kurose is a Distinguished Professor of Computer Science at the University of Massachusetts Amherst. His research interests include network protocols and architecture, network measurement, sensor networks, multimedia communication, and modeling and performance evaluation. He has served as Editor-in-Chief of the IEEE Transactions on Communications and was the founding Editor-in-Chief of the IEEE/ACM Transactions on Networking. He has been active in the program committees forIEEE Infocom, ACM SIGCOMM, ACM SIGMETRICS and ACM Internet Measurement conferences for a number of years, and has served as Technical Program Co-Chair for these conferences.He has received a number of research and teaching awards including the IEEE Infocom Award, the ACM Sigcomm Test of Time Award and the IEEE Taylor Booth Education Medal. With Keith Ross, he is the co-author of the textbook, Computer Networking, a top down approach (6th edition).He has been a visiting researcher at Technicolor's Paris Research Lab and at the LINCS (where is also a member of the LINCS Scientific Advisory Board) in 2012.
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Date:22/01/2014, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Michele Tortelli (Politecnico di Bari)
Talk:COBRA: Lean Intra-domain Routing in NDN
Abstract:Named Data Networking (NDN) is an emerging In-formation Centric Networking architecture based on hierarchicalcontent names, in-network caching mechanisms, receiver-drivenoperations, and content-level security schema. NDN networkingprimitives and routing are based on content names and thereforeefficient content discovery of permanent as well as temporarilyavailable cached copies is a key problem to address. This paper ex-amines current NDN approaches and proposes a fully distributed,content-driven, bloom filter-based intra-domain routing algorithm(COBRA), which outperforms previous solutions in this area.COBRA creates routes based on paths used previously for contentretrieval, and maintains routing information up-to-date withoutthe need for extensive signaling between nodes. We evaluateCOBRA using simulation and compare its performance with otherestablished routing strategies over the European research networkGEANT topology as an example of a ndnSIM core network. Ourresults illustrate that COBRA can significantly reduce overheadwith respect to flood-based routing while ensuring hit distancesof the same order as when using Dijkstra's algorithm.joint work with L.A. Grieco, G. Boggia, and K. Pentikousis, appering in the Procedings of IEEE Consumer Communications & Networking Conf. (CCNC), 2014
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Date:15/01/2014, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Laurent Massouli� (INRIA and Microsoft Research)
Talk:Community detection in stochastic block models via spectral methods
Abstract:Community detection consists in identification of groups of similaritems within a population. In the context of online social networks, it isa useful primitive for recommending either contacts or news items tousers. We will consider a particular generative probabilistic model forthe observations, namely the so-called stochastic block model, andgeneralizations thereof. We will describe spectral transformations andassociated clustering schemes for partitioning objects into distinctgroups. Exploiting results on the spectrum of random graphs, we willestablish consistency of these approaches under suitable assumptions,namely presence of a sufficiently strong signal in the observed data. Wewill also discuss open questions on phase transitions for clusterdetectability in such models when the signal becomes weak. In particularwe will introduce a novel spectral method which provably allows detectionof communities down to a critical threshold, thereby settling an openconjecture of Decelle, Krzakala, Moore and Zdeborov�.
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Date:08/01/2014, 14h - 15h
Room:LINCS Salle du Conseil
Speaker:Brigitte Cardinael (Orange)
Talk:Presentation du PPP 5G
Biography:Brigitte CARDINAELHead of Cooperative ResearchFrance Telecom OrangeBrigitte Cardinael was graduated at INT in 1987. She joined Matra Communication in 1987,where she was involved during 6 years in the research and development for GSM. Then shejoined France Telecom Research and Development (FTRD) in 1993 where she worked firston mobile satellite component in context of IMT-2000. After France Telecom investment inGlobalstar she was the coordinator of Globalstar activities at FTR&D from 1995 to 1999. Shejoined in 2002 the management team of the R&D Division on Mobile Services and RadioSystems as Innovation and Strategy manager. She was also in charge from 2001 till 2005 of coordinating Beyond 3G activities which includes France Telecom involvement in FP6 (Winner, E2R, Ambient Network, Daidalos, SPICE, MAGNET and 4MORE) and in international bodies (WWRF, SDRF, IEEE, 3GPP, IETF,...). She is since January 2006 headof cooperative research at France Telecom R&D. She has been eMobility Vice Chairman in 2006 and 2007. She is chairing the ETNO R&D group and the eMobility Testing Facilities WG.
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Date:18/12/2013, 14h - 15h
Room:Amphi Saphir
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Date:11/12/2013, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Vern Paxon (UC Berkeley and ICSI)
Talk:Combating Internet Attacks Via Infiltration
Abstract:Far and away the most energetic driver of modern Internet attacks is theability of attackers to financially profit from their assaults. Many ofthese undertakings however require attackers to operate at a scale thatnecessitates interacting with unknown parties - rendering their activitiesvulnerable to *infiltration* by defenders. This talk will sketch researchthat has leveraged such infiltration to striking effect.
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Date:04/12/2013, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Luca De Cicco (Politecnico di Bari)
Talk:Understanding the Dynamic Behaviour of the Google Congestion Control
Abstract:Real-time communication over the Internet is of everincreasing importance due the diffusion of portable devices, suchas smart phones or tablets, with enough processing capacitytosupport video conferencing applications. The RTCWeb workinggroup has been established with the goal of standardizing a setof protocols for inter-operable real-time communication amongWeb browsers. In this paper we focus on the Google CongestionControl (GCC), recently proposed in such WG, which is basedon a loss-based algorithm run at the sender and a delay-based algorithm executed at the receiver. In a recent work wehave shown that a TCP flow can starve a GCC flow. In thiswork we show that this issue is due to a threshold mechanismemployed by the delay-based controller. By carrying out anextensive experimental evaluation in a controlled testbed, wehave found that, when the threshold is small, the delay-basedalgorithm prevails over the loss-based algorithm, which containsqueuing delays and losses. However, a small threshold may leadto starvation of the GCC flow when sharing the bottleneck witha loss-based TCP flow. This is a joint with G. Carlucci and S. Mascolo, and will be presented at Packet Video Workshop, San Jose, CA, USA, December 2013
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Date:27/11/2013, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Nanette S. Levinson (American University Washington DC)
Talk:Adaptive Internet Governance: Innovation in the Ecosystem
Abstract:The years following the United Nation's World Summit on the Information Society (WSIS) have seen much technological change related to the Internet as well as significant innovation related to the discussion of Internet policy issues. Reporting on an institutional innovation in the Internet governance ecosystem, the research to be discussed examines the approximately eight-year-old Internet Governance Forum, highlights the growing roles of civil society including academics and technical experts, and tracks especially recent tensions among ecosystem actors. It also highlights the ecosystem's evolution and the roles of Multistakeholderism. Finally, it analyzes recent developments and identifies future directions.
Biography:Nanette S. Levinson is Associate Professor of International Relations, School of International Service, American University and Academic Director of the SIS- Sciences-Po Exchange. She is a past Chair of the Global Internet Governance Academic Network (GigaNet) and Editor of the International Communication Section in Robert Denemark, Editor,The International Studies Compendium Project. Oxford: Wiley-Blackwell. From 1988-2005 she served as Associate Dean of the School of International Service.Recipient of awards including those for outstanding teaching, program development, academic affairs administration, multicultural affairs and honors programming, she has designed co-curricular collaborative learning opportunities including the Freshman Service Experience and the Graduate Portal Program. Additionally, she has crafted and implemented research-based training programs for the private and public sectors. In 2011, the Ashoka Foundation presented her with an "Award for Outstanding Contributions to Social Entrepreneurship Education" and included her peer-reviewed syllabus in its list and publication of the top ten syllabi in the field. Her research and teaching focus on knowledge transfer, culture, and innovation in a range of settings including cross-national alliances; internet and global governance; cross-national, virtual collaboration; and social entrepreneurship. Also included is work centering on interorganizational learning and institutional change with special focus on new media and technology policy issues in the developing world. Prof. Levinson's writings appear online and in journals ranging from Information Technologies and International Development to International Studies Perspectives. She received her bachelor's, masters and doctoral degrees from Harvard University.
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Date:26/11/2013, 14h
Room:LINCS, Salle de Conseil
Speaker:Sean Meyn (University of Florida)
Talk:Feature Selection for Neuro-Dynamic Programming
Abstract:Neuro-Dynamic Programming encompasses techniques from both reinforcement learning and approximate dynamic programming. Feature selection refers to the choice of basis that defines the function class that is required in the application of these techniques. This talk reviews two popular approaches to neuro-dynamic programming, TD-learning and Q-learning. The main goal of this work is to demonstrate how insight from idealized models can be used as a guide for feature selection for these algorithms. Several approaches are surveyed, including fluid and diffusion models, and the application of idealized models arising from mean-field game approximations. The theory is illustrated with several examples. This talk based on (i) D. Huang, W. Chen, P. Mehta, S. Meyn, and A. Surana. Feature selection for neuro-dynamic programming. In F. Lewis, editor, Reinforcement Learning and Approximate Dynamic Programming for Feedback Control. Wiley, 2011 and (ii) S. P. Meyn. Control Techniques for Complex Networks. Cambridge University Press, Cambridge, 2007.
Biography:Sean Meyn received the B.A. degree in mathematics from the University of California, Los Angeles (UCLA), in 1982 and the Ph.D. degree in electrical engineering from McGill University, Canada, in 1987 (with Prof. P. Caines, McGill University). He is now Professor and Robert C. Pittman Eminent Scholar Chair in the Department of Electrical and Computer Engineering at the University of Florida, the director of the Laboratory for Cognition & Control, and director of the Florida Institute for Sustainable Energy. His academic research interests include theory and applications of decision and control, stochastic processes, and optimization. He has received many awards for his research on these topics, and is a fellow of the IEEE. He has held visiting positions at universities all over the world, including the Indian Institute of Science, Bangalore during 1997-1998 where he was a Fulbright Research Scholar. During his latest sabbatical during the 2006-2007 academic year he was a visiting professor at MIT and United Technologies Research Center (UTRC). His award-winning 1993 monograph with Richard Tweedie, Markov Chains and Stochastic Stability, has been cited thousands of times in journals from a range of fields. For the past ten years his applied research has focused on engineering, markets, and policy in energy systems. He regularly engages in industry, government, and academic panels on these topics, and hosts an annual workshop at the University of Florida.
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Date:13/11/2013, 14h00 - 14h30
Room:LINCS, Salle du Conseil
Speaker:Oana Goga (LIP6/UPMC)
Talk:Reliable and Scalable Account Correlation Across Large Social Networks
Abstract:There is lot of interest and concern, both in research and industry, about the potential for correlating user accounts across multiple online social networking sites. In this paper, we focus on the challenge of designing account correlation schemes that achieve high reliability, i.e., low error rates, in matching accounts, even when applied in large-scale networks with hundreds of millions of user accounts. We begin by identifying four important properties --Availability, Consistency, non-Impersonability, and Discriminability (ACID)-- that features used for matching accounts need to satisfy in order to achieve reliable and scalable account correlation. Even though public attributes like name, location, profile photo, and friends do not satisfy all the ACID properties, we show how it is possible to leverage multiple attributes to build SCALABLE- LINKER, a reliable and scalable account correlator. We evaluate the performance of SCALABLE-LINKER in correlating accounts from Twitter and Facebook, two of the largest real-world social networks. Our tests using ground truth data about correlated accounts, show that while SCALABLE-LINKER can correlate as high as 89% of accounts (true positive rate) with less than 1% false positive rate, when evaluated over small thousand node subsets of Facebook accounts, the true positive rate drops to 21% (keeping the 1% false positive rate), when the evaluation scale to include all the more than billion Facebook accounts. Our findings reflect the potential as well as the limits of reliably correlating accounts at scale using only public attributes of accounts.
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Date:06/11/2013, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Hugues Fauconnier et Carole Delporte
Talk:Dtecteurs de dfaillances
Abstract:Les dtecteurs de dfaillances ont t introduit par Chandra et Toueg en 1996 et ont t l'objet d'une recherche active depuis cette date.On prsentera les dtecteurs de dfaillances, les notions de rduction et de plus faible dtecteur de dfaillances pour rsoudre un problme en prsence de panne. On fera ensuite un tat de l'art sur les rsultats obtenus ainsi que sur les implmentations des dtecteurs de dfaillances.
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Date:23/10/2013, 14h00 - 14h30
Room:LINCS, Salle du Conseil
Speaker:Sebastien Faye (Telecom ParisTech)
Talk:LINCS PhD seminar - Adaptive traffic light control using a wireless sensor network
Abstract:We consider the problem of controlling traffic lights in an urban environment composed of multiple adjacent intersections by using an intelligent transportation system to reduce congestion and delays. Traditionally, each intersection is managed statically: the order and durations of the green lights are pre-determined and do not adapt dynamically to the traffic conditions. Detectors are sometimes used to count vehicles on each lane of an intersection but the data they report is generally used only to select between a few static sequences and timings setups. Here, we detail and study TAPIOCA, a distribuTed and AdaPtIve intersectiOns Control Algorithm that decides of a traffic light schedule. After a review of relevant related works, we first expose and evaluate the TAPIOCA algorithm, using the SUMO simulator and the TAPASCologne dataset. We then study the use of a hierarchical wireless sensor network deployed at intersections and the consequences of losses and delays it induces on TAPIOCA. Last but not least, we propose a prediction mechanism that alleviates these issues and show, using co-simulation between SUMO and OMNeT++, that such interpolation mechanisms are effectively able to replace missing or outdated data.
Biography:Sébastien Faye obtained a master degree in computer science from the university of Picardie Jules Verne (Amiens, France) in 2011. He is currently a PhD student at the Computer Science and Networking Department (INFRES) of Telecom ParisTech (Paris, France). His research interests include Intelligent Transportation Systems and sensor networks.
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Date:15/10/2013, 10h30 -- 11h30
Room:LINCS, Salle du Conseil
Speaker:Ravi R. Mazumdar (University of Waterloo)
Talk:Randomized Load Balancing in Large Processor Sharing Systems
Abstract:Processor sharing models occur in a wide variety of situations. They are good models forbandwidth sharing as well as being solutions to NUM for logarithmic utilities. In addition theypossess the desirable stochastic property of the stationary distribution being insensitive to the service time distribution. In this talk I will discuss new advances in understanding and characterizingthe behavior of randomized routing to PS servers that are heterogeneous in terms of their servercapacities.In particular, starting with the identical server case we will rst discuss the so-called Power-of-two rule where by a combination of routing to the least occupied server amongst two randomlychosen servers results in a very low server occupancy and a so-called propagation of chaos orasymptotic independence. Using these insights we analyze the case of heterogeneous servers wherethe server capacity can be one of M. We provide a complete characterization of the stationarydistribution and prove that the limiting system is insensitive. We then consider a modied criterionbased on routing to the server with lower Lagrange costs. We compare these dynamic routingstrategies with an optimal static state independent scheme. We show that the dynamic schemesare much better in terms of average delay with the Lagrange cost based being the best.The techniques are based on a mean eld analysis and an ansatz based on propagation of chaos.Joint work with Arpan Mukhopadhyay (Waterloo).
Biography:The speaker was educated at the Indian Institute of Technology, Bombay (B.Tech, 1977),Imperial College, London (MSc, DIC, 1978) and obtained his PhD under A. V. Balakrishnan at UCLA in1983.He is currently a University Research Chair Professor in the Dept. of ECE at the University of Waterloo,Ont., Canada where he has been since September 2004. Prior to this he was Professor of ECE at PurdueUniversity, West Lafayette, USA. He is a Fellow of the IEEE and the Royal Statistical Society. He isa recipient of the INFOCOM 2006 Best Paper Award and was runner-up for the Best Paper Award atINFOCOM 1998.His research interests are in modeling, control, and performance analysis of both wireline and wirelessnetworks, and in applied probability and stochastic analysis with applications to queueing, ltering, andoptimization.
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Date:09/10/2013, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Jordi Domingo-Pascual (Universitat Politecnica de Catalunya)
Talk:Locator/ID split: Analysis of the caching system
Abstract:Locator/Identifier splitting is a paradigm proposed to help Internet scalability. At the same time, the separation of the locator and the identifier name spaces allows for a more flexible management of traffic engineering, mobility and multi.homing. A mapping system is require for the binding of locators and identifiers. This mapping is helped by the use of a cache where ongoing associations are kept. The management and dimensioning of this cache is a critical aspect of this new architecture for its future deployment. We present a model for the caching system and and evaluation of its behaviour using real traffic traces.The talk will present the recent research work on LOC/ID splitting architectures.
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Date:18/09/2013, 14h00 - 14h30
Room:LINCS, Salle du Conseil
Speaker:Alexandre Maurer (LIP6/UPMC)
Talk:Tolerating Byzantine failures in sparse networks
Abstract:As network grow larger and larger, they become more likely to fail locally. Indeed, the nodes may be subject to attacks, failures, memory corruption... In order to encompass all possible types of failures, we consider the more general model of failure: the Byzantine model, where the failing nodes have an arbitrary malicious behavior. In other words, tolerating Byzantine nodes implies to ensure that there exists no strategy (however unlikely it may be) for the Byzantine nodes to destabilize the network.We thus consider the probleme of reliably broadcasting a message in a multihop network that is subject to Byzantine failures. Solutions exist, but require a highly-connected network. In this talk, we present our recent solutions for Byzantine-resilient broadcast in sparse networks, where each node has a very limited number of neighbors. A typical example is the grid, where each node has at most 4 neighbors. We thus show the tradeo-ff between connectivity and reliability.
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Date:18/09/2013, 14h30 - 15h00
Room:LINCS, Salle du Conseil
Speaker:Riad Mazloum (LIP6/UPMC)
Talk:Violation of interdomain routing assumptions
Abstract:We challenge a set of common assumptions that are frequently used tomodel interdomain routing in the Internet. We draw assumptions from thescientific literature and confront them with routing decisions that areactually taken by ASes, as seen in BGP feeds. We show that the assumptions aretoo simple to model real-world Internet routing policies. We also show thatASes frequently route in ways that are inconsistent with simple economicmodels of AS relationships. Our results should introduce a note of cautioninto future work that makes these assumptions and should prompt attempts tofind more accurate models.
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Date:04/09/2013, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Dohy Hong and Alonso Silva (Alcatel Lucent Bell Labs)
Talk:Game theory based economical model of large graph exploitation: illustration for the churn management.
Abstract:Churn rate is the percentage rate at which customers discontinue using a service. Every service provider has a churn prediction model where the objective is to minimize the churn rate by giving discounts or offers to customers susceptible to churn. In the following work, we present a preliminary model based on game theory and heuristics which perform well in an multi-period stage to maximize the revenue of the service providers under different scenarios.
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Date:28/08/2013, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Sarthak Grover
Talk:Peeking Behind the NAT: An Empirical Study of Home Networks
Abstract:We present the first empirical study of home network avail- ability, infrastructure, and usage, using data collected from home networks around the world. In each home, we de- ploy a router with custom firmware to collect information about the availability of home broadband network connec- tivity, the home network infrastructure (including the wire- less connectivity in each home network and the number of devices connected to the network), and how people in each home network use the network. Outages are more frequent and longer in developing countries sometimes due to the network, and in other cases because they simply turn their home router off. We also find that some portions of the wire- less spectrum are extremely crowded, that diurnal patterns are more pronounced during the week, and that most traf- fic in home networks is exchanged over a few connections to a small number of domains. Our study is both a prelim- inary view into many home networks and an illustration of how measurements from a home router can yield significant information about home networks. This is joint work with Mi Seon Park, Srikanth Sundaresan, Sam Burnett, Hyojoon Kim, Nick Feamster. It will appear at IMC 2013.
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Date:17/07/2013, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Marceau Coupechoux (Telecom ParisTech)
Talk:POMDP Approach for Pilot Allocation and Receive Antenna Selection
Abstract:This talk considers antenna selection (AS) at a receiver equipped with multiple antenna elements but only a single radio frequency chain for packet reception. As information about the channel state is acquired using training symbols (pilots), the receiver makes its AS decisions based on noisy channel estimates. Additional information that can be exploited for AS includes the time-correlation of the wireless channel and the results of the link-layer error checks upon receiving the data packets. In this scenario, the task of the receiver is to sequentially select (a) the pilot symbol allocation, i.e., how to distribute the available pilot symbols among the antenna elements, for channel estimation on each of the receive antennas; and (b) the antenna to be used for data packet reception. The goal is to maximize the expected throughput, based on the past history of allocation and selection decisions, and the corresponding noisy channel estimates and error check results. Since the channel state is only partially observed through the noisy pilots and the error checks, the joint problem of pilot allocation and AS is modeled as a partially observed Markov decision process (POMDP). The solution to the POMDP yields the policy that maximizes the long-term expected throughput. Using the Finite State Markov Chain (FSMC) model for the wireless channel, the performance of the POMDP solution is compared with that of other existing schemes, and it is illustrated through numerical evaluation that the POMDP solution significantly outperforms them.
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Date:10/07/2013, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Luigi Iannone (Telecom ParisTech)
Talk:Toward an Enhanced Internet Architecture: the Locator/Identifier Separation Protocol (LISP)
Abstract:The Locator/ID Separation Protocol (LISP), proposed by Cisco and currently under standardization at the IETF (Internet Engineering Task Force), is an instantiation of the paradigm separating locators and identifiers. LISP improves Internetu2019s scalability, also providing additional benefits (e.g., support for multi- homing, traffic engineering, mobility, etc.) and having good incremental deployability properties. The talk will overview the principles of LISP, its use in context different from Internet scalability, and some of the ongoing work in Telecom ParisTech.
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Date:03/07/2013, 14h00 - 14h30
Room:LINCS, Salle du Conseil
Speaker:Thomas Bourgeau (LIP6/UPMC)
Talk:Efficient IP-level network topology capture
Abstract:Large-scale distributed traceroute-based measurement systems are used to obtain the topology of the Internet at the IP-level and can be used to monitor and understand the behavior of the network. However, existing approaches to measuring the public IPv4 network space often require several days to obtain a full graph, which is too slow to capture much of the network's dynamics. This paper presents a new network topology capture algorithm, NTC, which aims to better capture network dynamics through accelerated probing, reducing the probing load while maintaining good coverage. There are two novel aspects to our approach: it focuses on obtaining the network graph rather than a full set of individual traces, and it uses past probing results in a new, adaptive, way to guide future probing. We study the performance of our algorithm on real traces and demonstrate outstanding improved performance compared to existing work. More info http://ntc.top-hat.info/index.html
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Date:03/07/2013, 14h30 - 15h00
Room:LINCS, Salle du Conseil
Speaker:Remi Leone (Thales TAI/Telecom ParisTech)
Talk:Optimizing QoS in Wireless Sensor Networks Using a Caching Platform
Abstract:This paper addresses monitoring and surveillance applications using WirelessSensors Networks (WSN). In this context, several remote clients are interestedin receiving the information collected by the nodes in a WSN@. As WSN devices are most of the time constrained in energy and processing, we present a caching architecture that will help reducing unnecessary communications and adapting the network to application needs. Our aim here is to cache information in order to improve the overall network lifetime, while meeting requirements of external application in terms information freshness.We first describe and evaluate the performance of our caching system within the framework of a Constrained Application Protocol (CoAP) proxy. We then extend this work by showing how the cache could be enriched and exploited with cross-layer data.Based on information from routing packets and estimation updates of nodes power consumption, we derive an optimization strategy which allows to meet requirements on the freshness of the cached values.
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Date:26/06/2013, 15h30 - 16h30
Room:Barrault, Amphi Saphir
Speaker:Jacques Sakarovitch (CNRS - Telecom ParisTech)
Talk:The validity of weighted automata
Abstract:In this talk, I address the problem of the validity of weighted automata in which the presence of epsilon-circuits results in infinite summations. Earlier works either rule out such automata or characterise the semirings in which these infinite sums are all well-defined. By means of a topological approach, we take here a definition of validity that is strong enough to insure that in any kind of semirings, any closure algorithm will succeed on every valid weighted automaton and turn it into an equivalent proper automaton. This definition is stable with respect to natural transformations of automata. The classical closure algorithms, in particular algorithms based on the computation of the star of the matrix of epsilon-transitions, can not be used to decide validity. This decision problem remains open for general topological semirings. We present a closure algorithm that yields a decision procedure for the validity of automata in the case where the weights are taken in Q or R. This case had never been treated before and we wanted to include in the Vaucanson platform.Joint work with Sylvain Lombardy (Universit� de Bordeaux).
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Date:19/06/2013, 11h-12h
Room:LINCS, Salle du Conseil
Speaker:Venkat Anantharam (University of California, Berkeley)
Talk:Nash equilibrium structure of a class of blocking games arising in network security
Abstract:We study a game-theoretic model for security/availability in a networkingcontext. To perform some desired task, a defender needs to choose a subsetfrom a set of resources. To perturb the task, an attacker picks a resource to attack.We model this scenario as a 2-player game and areinterested in describing its set of Nash equilibria. The games we study have a particular structure, for which we can use the theory of blocking pairs of polyhedra, pioneered by Fulkerson, to arrive a reasonably satisfactory understanding of the Nash equilibria.The subsets of resources that support Nash equilibrium strategies of the attacker,called "vulnerability sets", are of particular interest, and we identify them in severalspecific games of this type. An example of a game of this sort is when the set ofresources is the set of edges of a connected graph,the defender chooses as its subset the edges of a spanning tree,and the attacker chooses an edge to attack with the aim ofbreaking the spanning tree. (joint work with Assane Gueye, Aron Laszka, and Jean Walrand)
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Date:19/06/2013, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Chi Wan Sung (City University of Hong Kong)
Talk:Sparse Network Code for Wireless Broadcast
Abstract:Network coding has been shown to be an effective technique to increase throughput and delay performance in a wide range of network scenarios. This talk focuses on the application of network coding to wireless broadcast. An overview of existing coding methods will be provided. Among others, random linear network code (RLNC) and instantly decodable network code (IDNC) are two popular choices. RLNC is throughput optimal but suffers from slow decoding, whereas IDNC has fast decoding but is suboptimal in throughput especially when the number of users is large. In between these two extremes is our recently proposed method called sparse network coding (SNC). This talk will present the design of this coding algorithm and some related computational complexity questions. Performance comparison with RLNC and IDNC will also be made.
Biography:Chi Wan (Albert) Sung received his B.Eng, M.Phil and Ph.D in Information Engineering from the Chinese University of Hong Kong in 1993, 1995, and 1998, respectively. He worked in the Chinese University of Hong Kong as an Assistant Professor from 1998 to 1999. He joined City University of Hong Kong in 2000, and is now an Associate Professor of the Department of Electronic Engineering.He is an Adjunct Associate Research Professor in University of South Australia, and is on the editorial board of the ETRI journal and of the Transactions on Emerging Telecommunications Technologies (ETT).His research interests include wireless communications, network coding, information theory, and algorithms and complexity.
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Date:12/06/2013, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Michal Pioro (Lunds Universitet)
Talk:Integer programming models for transmission scheduling in wireless networks.
Abstract:In the presentation, we will discuss exact integer programming models for transmission scheduling in wireless networks based on the notion of compatible set.A compatible set is defined as a subset of radio links that can transmit simultaneously with acceptable interference. The issue is to find a set of compatible sets that, when properly interlaced in the transmission slots, will maximize a traffic objective. We will present integer programming formulations of the underlying optimization problem and discuss their computational effectiveness.
Biography:Michal Pi�ro is a professor and Head of the Computer Networks and Switching Division at the Institute of Telecommunications, Warsaw University of Technology, Poland. At the same time he is a professor at Lund University, Sweden. He received a Ph.D. degree in telecommunications in 1979, and a D.Sc. degree (habilitation) in 1990, both from the Warsaw University of Technology. In 2002 he received a Polish State Professorship. His research interests concentrate on modeling, optimization and performance evaluation of telecommunication networks and systems. He is an author of four books and more than 150 technical papers presented in the telecommunication journals and conference proceedings. He has led many research projects for telecom industry in the field of network modeling, design, and performance analysis. He is deeply involved in international research projects including the FP7, Celtic and COST projects.
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Date:07/06/2013, 15h00-15h30
Room:Amphi Emeraude
Speaker:Thomas Hujsa, LIP6/UPMC
Talk:Polynomial Sufficient Conditions of Well-Behavedness for Weighted Join-Free and Choice-Free System
Abstract:Join-Free Petri nets, whose transitions have at most one input place, model systems without synchronizations while Choice-Free Petri nets, whose places have at most one output transition, model systems without conflicts. These classes respectively encompass the state machines (or S-systems) and the marked graphs (or T-systems).Whereas a structurally bounded and structurally live Petri net graph is said to be "well-formed", a bounded and live Petri net is said to be "well-behaved". Necessary and sufficient conditions for the well-formedness of Join-Free and Choice-Free nets have been known for some time, yet the behavioral properties of these classes are still not well understood. In particular efficient sufficient conditions for liveness have not been found until now.We extend results on weighted T-systems to the class of weighted Petri nets and present transformations which preserve the feasible sequences of transitions and reduce the initial marking. We introduce a notion of "balancing" that makes possible the transformation of conservative systems into so-called "1-conservative systems" while retaining the feasible transition sequences. This transformation leads to polynomial sufficient conditions of liveness for well-formed Join-Free and Choice-Free nets. More info http://www.mefosyloma.fr/j2013-06-07.html
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Date:07/06/2013, 14h00-15h00
Room:Amphi Emeraude
Speaker:Petr Kuznetsov
Talk:Wait-Freedom with Advice
Abstract:It is well-known that most problems in distributed computing cannot be solved in a wait-free manner, i.e., ensuring that processes are able to make progress independently of each other. The failure-detector abstraction was proposed to circumvent these impossibilities. Intuitively, a failure detector provides each process with some (possibly incomplete and inaccurate) information about the current failure pattern, which allows the processes to wait for each other in order to compute a consistent output.We motivate and propose a new way of thinking about failure detectors which allows us to define, quite surprisingly, what it means to solve a distributed task wait-free using a failure detector. We separate computation processes that obtain inputs and are supposed to produce outputs from synchronization processes that are subject to failures and can query a failure detector. In our framework, we obtain a complete classification of tasks, including ones that evaded comprehensible characterization so far, such as renaming or weak symmetry breaking. More info http://www.mefosyloma.fr/j2013-06-07.html
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Date:05/06/2013, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:~4 LINCS PhDs
Talk:LINCS PhD seminar
Abstract:more details to come
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Date:04/06/2013, 11h-12h
Room:LINCS, Salle du Conseil
Speaker:J�r�mie Jakubowicz (T�l�com SudParis)
Talk:From Gossip to Distributed Optimization (and back again)
Abstract:Consensus in a network is a fundamental, thoroughly, studied problem. It is well known that the main obstacles to it are unreliability and asynchronism as stated by the celebrated "FLP impossibility result". However under smoother assumptions, several works in the past decade have shown that consensus can be reached using very simple algorithms known as Gossip. Interestingly enough, these gossip algorithms turned out essential in the more complex setting of distributed optimization where the sought consensus has to solve an optimization problem.The first part of this talk will introduce the main concepts and tools: distributed algorithms, gossip, distributed optimization. In a second part of the talk, I will discuss how to rely on distributed optimization to build more robust gossip schemes.
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Date:29/05/2013, 14h - 15h
Room:Amphi Saphir
Speaker:Marco Mellia (Politecnico di Torino)
Talk:Internet traffic monitoring: Discerning Content and Services in a Tangled Web
Abstract:A careful perusal of the Internet evolution reveals two major trends - explosion of cloud-based services and video streaming applications. In both of the above cases, the owner (e.g., CNN, YouTube, or Zynga) of the content and the organization serving it (e.g., Akamai, Limelight, or Amazon EC2) are decoupled, thus making it harder to understand the association between the content, owner, and the host where the content resides. This has created a tangled world wide web that is very hard to unwind. In this picture, ISPs and network administrators are losing the control of their network while struggling to find new mechanisms to increase revenues.In this talk, I'll present some measurement to show the tangle, showing some data about internet traffic, and some side-notes about user privacy.I'll then present Dn-Hunter, a system that leverages the information provided by DNS traffic to discern it. Parsing through DNS queries, traffic flows are tagged with the associated domain name. This association reveals a large amount of useful information to automatically discover (i) what services run on a layer-4 port or server, (ii) which content is accessed via TLS encryption, (iii) what content/service does a given CDN or cloud provider handle, and (iv) how a particular CDN or Cloud serves users' requests.Simply put, the information provided by DNS traffic is one of the key components required to unveil the tangled web, and to restore network and application visibility to the network administrators.
Biography:Marco Mellia graduated from the Politecnico di Torino with Ph.D. in Electronic and Telecommunication Engineering in 2001. Between February and October 1997, he was a Researcher supported by CSELT. He was a Visiting PhD Student starting from february 1999 to november 1999 at the Computer Science Department of theCarnegie Mellon University, where he worked with Prof. Hui Zhang and Ion Stoica. From February to March 2002 he visited the Sprint Advanced Technology Laboratories Burlingame, California, working at theIP Monitoring Project (IPMON). During the summer 2011 ans 2012 he visisted Narus Inc, Sunnyvale, California, where he worked on traffic classification problems.He has co-authored over 180 papers published in international journals and presented in leading international conferences, all of them in the area of telecommunication networks. He participated in the program committees of several conferences including ACM SIGCOMM, ACM CoNEXT, IEEE Infocom, IEEE Globecom and IEEE ICC. His research interest are in the design and investigation of energy efficient networks (green networks) and in the traffic monitoring and analysis. He is currently the coordinator of the mPlane Integrated Project that focusses on buling an Intelligent Measurement Plane for Future Network and Application ManagementCurrently he's working at the Dipartimento di Elettronica e Telecomunicazioni at Politecnico di Torino as an Assistant Professor
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Date:22/05/2013, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Tracy Camp (Colorado School of Mines)
Talk:SMOOTH: A Simple and Realistic Way to Model Human Mobility
Abstract:Simulation is the research tool of choice for a majority of the mobile ad hoc network (MANET) community; however, while the use of simulation has increased, the credibility of the simulation results has decreased. Since mobility patterns can significantly affect the performance of a protocol, choosing a realistic mobility model is one important aspect to consider in the development of a credible MANET simulation scenario.In addition to being realistic, a mobility model should be easy to understand and use. Unfortunately, most of the simple mobility models proposed thus far are not realistic and most of the realistic mobility models proposed thus far are not simple to use.In this seminar, I will present SMOOTH, a new mobility model that is realistic (e.g., SMOOTH is based on several known features of human movement) and is simple to use (e.g., SMOOTH does not have any complex input parameters). In addition to presenting SMOOTH, I will show results that validate SMOOTH imitates human movement patterns present in real mobility traces collected from a range of diverse scenarios and I will compare SMOOTH with other mobility models that have been developed on similar mobility traces. Lastly, I will discuss tools that my group has created to aid the development of more rigorous simulation studies. While this work focuses on the MANET field, the takeaway message in regards to credible simulation is applicable to other computing fields.
Biography:Tracy Camp is a Full Professor of Computer Science in the Department of Electrical Engineering and Computer Science at the Colorado School of Mines. She is the Founder and Director of the Toilers (http://toilers.mines.edu), an active ad hoc networks research group. Her current research interests include the credibility of ad hoc network simulation studies and the use of wireless sensor networks in geosystems. Dr. Camp has received over 20 grants from the National Science Foundation, including a prestigious NSF CAREER award. In total, her projects have received over $20 million dollars in external funding. This funding has produced 12 software packages that have been requested from (and shared with) more than 3000 researchers in 86 countries (as of October 2012). Dr. Camp has published over 80 refereed articles and 12 invited articles, and these articles have been cited almost 4,000 times (per Microsoft Academic Search) and over 7,000 times (per Google Scholar) as of December 2012.Dr. Camp is an ACM Fellow, an ACM Distinguished Lecturer, and an IEEE Senior Member. She has enjoyed being a Fulbright Scholar in New Zealand (in 2006), a Distinguished Visitor at the University of Bonn in Germany (in 2010), and a keynote presenter at several venues, e.g., at the 7th International Conference on Intelligent Sensors, Sensor Networks and Information Processing (ISSNIP 2011) in Adelaide, Australia, and the 3rd International Conference on Simulation Tools and Techniques (SIMUTools 2010) in Malaga, Spain. In December 2007, Dr. Camp received the Board of Trustees Outstanding Faculty Award at the Colorado School of Mines; this award was only given five times between 1998-2007. She shares her life with Max (born in 2000), Emma (born in 2003), her husband (Glen), and three pets (two cats and a dog). The four humans are vegetarians who tremendously enjoy living in the foothills of the Rockies.
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Date:14/05/2013, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Brigitte Jaumard (Concordia University)
Talk:Design of a Survivable VPN Topology over aService Provider Network
Abstract:Survivability in IP-over-WDM networks has alreadybeen extensively discussed in a series of studies. Up to date,most of the studies assume single-hop working routing of trafficrequests. In this paper, we study the multi layer survivable designof a virtual topology in the context of multiple-hop workingrouting for IP layer traffic requests. The design problem iscomposed of two problems which are simultaneously solved:( i ) Finding the most efficient or economical multi-hop routingof the IP traffic flows with different bandwidth granularitiesover the virtual topology, which involves some traffic grooming,( ii ) Ensuring that the virtual topology is survivable throughoutan appropriate mapping of the virtual links over the physicaltopology, if such a mapping exists.In order to solve such a complex multi layer resilient networkdesign problem, we propose a column generation ILP model. Itallows exploiting the natural decomposition of the problem andhelps devising a scalable solution scheme.We conducted numerical experiments on a German networkwith 50 nodes and 88 physical links. Not only we could solve muchlarger data instances than those published in the literature, butalso observe than multi-hop routing allows a saving of up to 10%of the number of lightpaths, depending on the traffic load.
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Date:03/05/2013, 10h30
Speaker:Uichin Lee (KAIST)
Talk:CLIPS: Infrastructure-free Collaborative Indoor Positioning Scheme for Time-critical Team Operation
Abstract:Indoor localization has attracted much attentionrecently due to its potential for realizing indoor location-awareapplication services. This talk considers a time-criticalscenario with a team of soldiers or first responders conductingemergency mission operations in a large building in whichinfrastructure-based localization is not feasible (e.g., due tomanagement/installation costs, power outage, terrorist attacks). In this talk, I will present a collaborative indoor positioning scheme called CLIPS that requires no preexisting indoorinfrastructure. Assuming that each user has a received signalstrength map for the area in reference, an application can compare and select a set of feasible positions,when the device receives actual signal strength values at runtime. Then, dead reckoning is performed to remove invalidcandidate coordinates eventually leaving only the correct onewhich can be shared amongst the team. The evaluation resultsfrom an Android-based testbed show that CLIPS converges toan accurate set of coordinates much faster than existing non-collaborativeschemes (more than 50% improvement under theconsidered scenarios).
Biography:Dr. Uichin Lee is an assistant professor in the Department of Knowledge Service Engineering at KAIST, Korea. He received his Ph.D. degree in Computer Science from UCLA in 2008. Before joining KAIST, he worked for Alcatel-Lucent Bell Labs at Holmdel as a member of technical staff. His research interests include mobile/pervasive computing and social computing systems.
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Date:30/04/2013, 14p
Speaker:Sean Meyn (Univ. of Florida)
Talk:Control of the grid in 2020, and how economics can help us.
Abstract:In this talk we survey control issues in the grid, and how the introduction of renewables brings new and interesting control problems. We also explain the need for economic theory to guide the formulation of contracts for resources needed for reliable real-time control. Control of the grid takes place on many time-scales, and is analogous to many other control problems, such as confronted in aviation. There is decision making on times scales of days, weeks, or months; much like the planning that takes place for ticket sales for a commercial airline. Hourly decision making of energy supply is analogous to the chatter between pilot and air traffic controller to re-adjust a route in response to an approaching thunderstorm. Then, there is regulation of the grid on time-scales of seconds to minutes; consider the second-by-second movement of the ailerons on the wings of an airplane, in response to disturbances from wind and rain hitting the moving plane. There are also transient control problems: The recovery of the grid following one generator outage is much like the take-off or landing of an airplane. It is important to keep these analogies in mind so that we can have an informed discussion about how to manage the volatility introduced to the grid through renewable energy sources such as wind and solar. The new control problems in the grid will be solved by engineers, as we have solved many similar control problems.
Biography:Sean Meyn received the B.A. degree in mathematics from the University of California, Los Angeles (UCLA), in 1982 and the Ph.D. degree in electrical engineering from McGill University, Canada, in 1987 (with Prof. P. Caines, McGill University). He is now Professor and Robert C. Pittman Eminent Scholar Chair in the Department of Electrical and Computer Engineering at the University of Florida, and director of the Laboratory for Cognition & Control. His research interests include stochastic processes, optimization, and information theory, with applications to power systems.
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Date:26/04/2013, 15h00 - 16h30
Room:Amphi Saphir,
Speaker:Katrin Wolf (TU Berlin)
Talk:Microinteractions: Finger mounted sonsors for ubiquitous and busy-hand interfaces
Abstract:I will present an approach that supports the idea of ubiquitous computing through finger mounted motion sensors. We are motivated to enable users for interacting with any grasped device through one generic wearable interface. Two prototypes illustrate that idea: Tickle (TEI 2013) allows for detecting mircogestures on any surface, various shapes, and generic devices through physically decoupling in- and output and attaching motion sensors on fingers for recognizing tiny finger movements as microgestures. Moreover we show that modelling the whole hand is possible with 8 sensor units and considering bio-mechanics (AH 2013). That allows for detecting any hand pose without suffering of occlusion or depending on certain light conditions. We finally discuss some hardware and gesture design challenges of our approach, but also show how our approach is a step into the direction of ubiquitous computing.
Biography:Currently I am a doctoral student in the Integrated Graduate Program in Human-Centric Communication (IGP H-C3) at TU Berlin, which is affiliated with the Telekom Innovation Laboratories. My research is on ergonomic design for gestural "busy-hand interfaces" and I am supervised by Sebastian M�ller (T-Labs Berlin) and Michael Rohs (University of Hannover). During my postgraduate studies I was an exchange student at Glasgow University and was supervised there by Stephen Brewster. Furthermore I did internships at CSIRO Australia and at HITLab New Zealend where I was supervised by Mark Billinghurst. Before my research career, I was a docent of multimedia design at the University of Applied Sciences Berlin in 2009 and I also worked as an interaction designer for the Jewisn Museum Berlin. For my Masters, I studied design and communications at the University of the Arts, Berlin.
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Date:25/04/2013, 14h-15h
Room:Amphi Jade
Speaker:Mounia Ziat (Northern Michigan University)
Talk:InGrid: Interactive Grid Table
Abstract:I will discuss the theoretical implications of the embodied perceptual and personal spaces in interactive tabletops and surfaces and presents InGrid, an Interactive Grid table. InGrid offers several affordances to the user that could not only interact with tangible and intangible objects but also with other users.
Biography:Mounia Ziat earned a B.A. in Electronics Engineering, a M.A and Ph.D in Technologies and Human Sciences. She also studied Arts for three years. She was a Postdoctoral Fellow at McGill University and at Wilfrid Laurier University and she served as a sessional lecturer at University of Guelph-Humber. Her research interests include haptic device design and HCI, human tactile and visual perception, cognitive neuroscience and BCI. She also enjoys scuba diving, camping, canoeing, and hiking. Mounia Ziat is an assistant professor at Northern Michigan University
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Date:24/04/2013, 13h30 - 17h00
Room:Amphi Grenat
Speaker:Annie Gentes (Telecom ParisTech) and Ted Selker (Carnegie Mellon Silicon Valley)
Talk:Social Science Meets Design Activities in Considerate Systems
Abstract:Information systems are now being called upon not only to help us keep organized and productive but also to help build the fabric of the way we live. They might help us focus by reducing disruption, they might engage in various activies to help people enjoy others, or they might even try to give people increasing self-awareness. This talk will introduce notions of how we can introduce social awareness in our design practices and artifacts. Dr. Selker will introduce lines of research that proceed from creating and evaluation design sketches around recognizing and respecting human intention. These design sketches and their experiments strive to lead to and are part of creating a considerate cyber physical world. Dr. Gentes will reflect on how considerate systems fit into reflective technologies that use genres and create new ones. Using methods from humanities, such as analysis of textual and visual contents, or consideration of social literacies can be helpful to the design and evaluation of information technologies. Annie and Ted are now engaged in writing a book which develops these ideas further: extending examples and theories of how concepts like poetics extend our understanding of technology creation and use.
Biography:Ted Selker's work is focused on bringing people together with technology. Ted Selker has been working to develop CMU Silicon Valley research program since 2009 where he runs the Considerate Computing group. He created and ran the Context Aware Computing group at MIT Media Lab research. At IBM he created the USER research group, drove inventions into products and became an IBM Fellow. He has also had research & teaching positions at Atari, PARC, Stanford and Hampshire College, etc. He consults to help companies from Google, Herman Miller and Pixar to startups. His successes at targeted product creation and enhancement have resulted in numerous products, awards, patents, and papers and have often been featured in the press.Annie Gentes is professor of Information and Communication Sciences at Telecom ParisTech. She is the head of the Codesign and Media Studies Lab, which studies the invention and design of New Media and Information Technology. She teaches graduate courses in new media art, innovation and design. She is responsible for the master program: "Design, Media, Technology" with the University Panth�on Sorbonne and the Ecole Nationale Superieure de Creation Industrielle. She teaches political communication at the Institute of Political Sciences in Lille. Her research focuses on defining the characteristics of ICT as reflexive technologies. She currently works with The Louvre Museum, Grand Palais, Arts and Crafts Museum, Contemporary Art Museum Beaubourg, and other cultural and art institutions.
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Date:24/04/2013, 14h - 15h
Room:LINCS, salle du conseil
Speaker:Daniela Tulone
Talk:Real-time Monitoring of Physical Phenomena and their Dynamics with Quality Guarantees via Wireless Sensor Networks
Abstract:Wireless sensor networks (WSN) are a powerful type of instrument with thepotential of remotely observing the physical world at high resolution and scale.However, to be an efficacious tool WSN monitoring systems must provideguarantees on the quality of the observations and mechanisms for real-timedata analysis. These problems are made challenging by the WSN limited resourcesand the high volume of sensor data. In this talk I will address both challenges andillustrate two monitoring solutions, which are built on top of statistical models andoffer dynamic trade-offs between resource efficiency and quality of service.More precisely, I will present an energy-efficient system, called SAF, for answeringon-line queries with quality guarantees, detecting at real-time anomalies, andclustering similar nodes. The system relies on a class of simple time series modelsbuilt at sensors, which are cheap to learn and dynamically adapt to variations in thedata distribution to accurately predict sensor values and improve resource utilization.SAF also provides an integrated fault detection system and a hierarchical scheme toimprove scalability in case of large-scale WSN.SAF limited capabilities to face complex dynamics and data instability are overcomeby the SmartEnv real-time monitoring system. It remarkably improves SAF and previouswork for providing probabilistic guarantees on the service quality even in case of sensormalfunctioning, data instability and temporal communication disruption, and for automaticallyanalyzing sensor data (e.g., trends, temporal-spatial correlations). SmartEnv is also ableto analyze anomalies, thus distinguishing between sensor malfunctioning and unexpectedvariations in the phenomenon.I will conclude my talk with an outline of some SmartEnv applications and future work,particularly in the context of smart cities/grids.
Biography:Daniela Tulone holds a Ph.D. in Computer Science from University of Pisajointly with MIT, a M.S. in Computer Science from NYU, and a B.S. and M.S. degree inMathematics from University of Catania. She has worked in academia and research labs(e.g., Bell-Labs, MIT, AT&T Labs, NYU, University of Pisa, C.N.R.), in R&D industry,and recently at the Joint Research Center of the European Commission.Her interests include wireless sensor networks, algorithms, secure distributed systems, thedesign of dynamic trade-offs, smart grids, data analysis, and whatever involves a blendof theory and applications
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Date:23/04/2013, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Longbo Huang, (Tsinghua University)
Talk:A Benes Packet Network
Abstract:Benes networks are constructed with simple switch modules and have many advantages, including small latency and requiring only an almost linear number of switch modules. As circuit-switches, Benes networks are rearrangeably non-blocking, which implies that they are full-throughput as packet switches, with suitable routing. Routing in Benes networks can be done by time-sharing permutations. However, this approach requires centralized control of the switch modules and statistical knowledge of the traffic arrivals. We propose a backpressure-based routing scheme for Benes networks, combined with end-to-end congestion control. This approach achieves the maximal utility of the network and requires only four queues per module, independently of the size of the network.
Biography:Longbo Huang is currently an assistant professor in the Institute for Interdisciplinary Information Sciences (IIIS) at Tsinghua University, Beijing, China. He received his Ph. D. degree from the Electrical Engineering department at the University of Southern California in August 2011, and worked as a postdoctoral researcher in the Electrical Engineering and Computer Sciences department at the University of California at Berkeley from July 2011 to August 2012. He was also a visiting professor at the Institute of Network Coding at the Chinese University of Hong Kong from December 2012 to February 2013. Prior to his Ph.D., Longbo received his B.E. degree from Sun Yat-sen (Zhongshan) University, Guangzhou, China, and his M.S. degree from Columbia University, New York City, both in EE. His research interests are in the areas of Stochastic Network Optimization, Data Center Networking, Smart Grid, Processing Networks and Queueing Theory.
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Date:17/04/2013, 14h - 15h
Speaker:Johanna Mathieu (ETH)
Talk:Controlling Electric Loads to Manage Energy Imbalances in Power Systems
Abstract:Increasing the share of energy produced by wind turbines, solar photovoltaics, and solar thermal power plants helps society address many key energy challenges including climate change, environmental degradation, and energy security. However, these renewable energy resources present new challenges, notably that their power production is intermittent u2013 they produce when the wind is blowing and the sun is shining, not necessarily when we need it. In this talk, I will describe how distributed flexible resources such as commercial buildings, residential electric loads, and distributed storage units can support high penetrations of intermittent renewables and provide other services that make the grid run more efficiently and make power less expensive. As an example, I will show how one can use Markov models and linear/nonlinear filtering techniques to centrally control aggregations of air conditioners to provide power system services with high accuracy, but low requirements for sensing and communications. Importantly, the approach ensures that control actions are non-disruptive to the consumer. I find that, depending on the performance required, loads may not need to provide state information to the central controller in real time or at all, which keeps installation and operation costs low. Additionally, I will discuss a number of practical issues including estimates of the resource size and revenue potential. Finally, I will describe several new research directions including modeling load aggregations as uncertain reserves for day-ahead power system planning and real-time security.
Biography:Johanna Mathieu is a postdoctoral researcher in the Power Systems Laboratory at ETH Zurich, Switzerland. In May 2012 she received her PhD in mechanical engineering from the University of California at Berkeley. She has a BS from MIT in ocean engineering and an MS from UC Berkeley in mechanical engineering.
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Date:15/04/2013, 14h - 15h
Room:LINCS, Salle de Conseil
Speaker:Lixia Zhang (UCLA)
Talk:NDN Reaching 3: Results and Challenges -- a personal perspective
Abstract:In this talk I plan to do a quick walk-throuhg for part of the works we have done over the last 2.5 years. More specifically I will discuss what we have learned in packet forwarding area and a new perspective on the relation between routing and forwarding planes (or control and data planes, as they are called today). I will also describe a few new applications we have developed over NDN and what we have learned in the process.
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Date:10/04/2013, 14h - 15h
Speaker:Izhak Rubin (UCLA)
Talk:Robust Mobile Wireless Networking
Abstract:Cellular wireless networks are expanded to support ultra high speed multimedia applications and incorporate the use of next generation energy efficient micro base stations in supporting much higher density of mobile stations. The operations of neighborhood base station nodes are coordinated in a cross-layer manner to mitigate interference, adapt to traffic rate fluctuations and autonomously react to failure events. In turn, mobile ad hoc networking mechanisms are investigated for multitude of applications, when the involved networking systems do not make use of a permanent backbone infrastructure. Hybrid architectures include systems that require dynamically adaptive multi hop access to backbone systems, and such that demand resilient access and rapid adaptations to communications system degradations. Applications are planned for hybrid systems that include vehicular networks that combine the use of multi hop ad hoc routing techniques, WiFi, cellular wireless access technologies, and cloud computing architectures. We will review our recent research developments and studies of such network systems, selecting from the following topics: 1. For cellular wireless networks : adaptive rate/power scheduling for multicasting and unicasting; micro base station aided resilient failover.; heterogeneous operations under the use of micro and macro base station layouts; design of resilient public safety network systems. 2. Vehicular ad hoc networks (VANETs): Location aware multicast packet distributions to highway vehicles using inter-vehicular wireless networking protocols. 3. Mobile ad hoc networks: mobile backbone networking (MBN).
Biography:Izhak Rubin received the B.Sc. and M.Sc. from the Technion, Israel, and the Ph.D. degree from Princeton University, Princeton, NJ, USA, in Electrical Engineering. Since 1970, he has been on the faculty of the UCLA School of Engineering and Applied Science where he is currently a Distinguished Professor in the Electrical Engineering Department. Dr. Rubin has had extensive research, publications, consulting, and industrial experience in the design and analysis of commercial and military computer communications and telecommunications systems and networks. Recent R&D projects include network design, simulation, management, and planning tools for network modeling and analysis, multi-task resource allocation, unmanned vehicle aided multi-tier ad hoc wireless communications networks; cross-layer adaptive power, rate and routing for mobile wireless cellular and ad hoc networks. He serves as co-director of the UCLA Public Safety Network Systems Laboratory. During 1979-1980, he served as Acting Chief Scientist of the Xerox Telecommunications Network. He served as co-chairman of the 1981 IEEE International Symposium on Information Theory; as program chairman of the 1984 NSF-UCLA workshop on Personal Communications; as program chairman for the 1987 IEEE INFOCOM conference; and as program co-chair of the IEEE 1993 workshop on Local and Metropolitan Area networks. Dr. Rubin is a Life Fellow of IEEE. He has served as an editor of the IEEE Transactions on Communications, Wireless Networks journal, Optical Networks magazine, IEEE JSAC issue on MAC techniques, Communications Systems journal, Photonic Networks Communications journal, and has contributed chapters to texts and encyclopedia on telecommunications systems and networks.
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Date:03/04/2013, 14h-16h
Room:LINC, Salle de Conseil
Speaker:The Dang Huynh (Alcatel-Lucent)
Talk:Analyzing methods solving system of linear equations in PageRank context
Abstract:Basic system of linear equations has attracted many research efforts. Various methods have been considered to solve this kind of equation, e.g. Jacobi, Gauss-Seidel, Successive Over-Relaxation, Generalized Minimal Residual and, recently proposed, D-Iteration. They are, of course, different in memory requirement, computation cost and thus convergence speed. In this paper, we dig into detail some criteria concerning the costs and compare those methods in different types of large matrices (e.g. web graphs, social network graphs, directed/undirected graph). The results presented in this paper are a first step to look for an algorithm which is suitable for very large matrices, in either sequential or parallel environment. Joint work with Dohy Hong, Gerard Burnside, Fabien Mathieu
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Date:03/04/2013, 14h-16h
Room:LINC, Salle de Conseil
Speaker:Yixi Gong (Telecom ParisTech)
Talk:Fighting the bufferbloat: on the coexistence of AQM and low priority congestion control
Abstract:Nowadays, due to excessive queuing, delays on the Internet can grow longer than several round trips between the Moon and the Earth -- for which the ``bufferbloat'' term was recently coined. Some point to active queue management (AQM) as the solution. Others propose end-to-end low-priority congestion control techniques (LPCC). Under both approaches, promising advances have been made in recent times: notable examples are CoDel for AQM, and LEDBAT for LPCC. In this paper, we warn of a potentially fateful interaction when AQM and LPCC techniques are combined: namely (i) AQM resets the relative level of priority between best effort and low-priority congestion control protocols; (ii) while reprioritization generally equalizes the priority of LPCC and TCP, we also find that some AQM settings may actually lead best effort TCP to starvation. By an extended set of experiments conducted on both controlled testbeds and on the Internet, we show the problem to hold in the real world for any tested combination of AQM policies and LPCC protocols. To further validate the generality of our findings, we complement our experiments with packet-level simulation, to cover cases of other popular AQM and LPCC that are not available in the Linux kernel. To promote cross-comparison, we make our scripts and dataset available to the research community. Joint work with Dario Rossi, Claudio Testa, Silvio Valenti and Dave Taht.
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Date:03/04/2013, 14h-16h
Room:LINC, Salle de Conseil
Speaker:Mathieu Leconte (Technicolor - INRIA)
Talk:Load balancing in distributed content distribution networks
Abstract:A centralized content distribution network (CDN) is a system in which users access contents stored in a few large data centers. On the contrary, in a distributed CDN, the contents are stored in a swarm of small servers, each with limited storage and service capacities. In such a setup, in it unclear how to operate the system in the best possible way and what its performances will be. Indeed, in a centralized CDN, the capacity of the system, in terms of number of requests that can be similtaneously served, is simply the total upload capacity of the data centers, as each data center has enough capacity to store the whole catalog of contents (or it would require little adjustement to make sure the requested contents are available). However, in a distributed CDN, we cannot assume that requested contents will always be stored in the available servers anymore and on-the-go adjustements would be too costly, and computing the capacity of the system becomes an issue. This problem is known as a load-balancing problem.We model distributed CDNs via random bipartite graphs, whose distribution depends on how the network is operated, i.e. how the contents are replicated within the servers. We compute the capacity of such a system (i.e. the size of a maximum capacitated matching of the graph) in the limit of large systems, and then compare and optimize over diverse replication policies. The method used is the so-called cavity method from statistical physics, which involves the study of message passing algorithms (belief-propagation) on random graphs.
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Date:03/04/2013, 14h-16h
Room:LINC, Salle de Conseil
Speaker:Tiphaine Phe-Neau (UPMC Sorbonne Universites)
Talk:The Strength of Vicinity Annexation in Opportunistic Networking
Abstract:Most disruption-tolerant networking protocols focus on mere contact and intercontact characteristics to make forwarding decisions. We propose to relax such a simplistic approach and include multi-hop opportunities by annexing a node's vicinity to its network vision. We investigate how the vicinity of a node evolves through time and whether such knowledge is useful when routing data. By analyzing a modified version of the pure WAIT forwarding strategy, we observe a clear tradeoff between routing performance and cost for monitoring the neighborhood. By observing a vicinity-aware WAIT strategy, we emphasize how the pure WAIT misses interesting end-to-end transmission opportunities through nearby nodes. For the datasets we consider, our analyses also suggest that limiting a node's neighborhood view to four hops is enough to improve forwarding efficiency while keeping control overhead low. (Accepted at the Fifth IEEE INFOCOM International Workshop on Network Science for Communication Networks (IEEE NetSciCom 2013)
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Date:03/04/2013, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:~4 LINCS PhDs
Talk:LINCS PhD seminar
Abstract:more details to come
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Date:29/03/2013, 14h - 15h
Speaker:Yezekael Hayel (Universit� d'Avignon)
Talk:Optimization of Decentralized Partially Observable Systems in Cognitive Radio Networks
Abstract:We consider a non-cooperative Dynamic Spectrum Access (DSA) game where Secondary Users (SUs) access opportunistically the spectrum licensed for Primary Users (PUs). As SUs spend energy for sensing licensed channels, they may choose to be inactive during a given time slot in order to save energy. Then, there exists a tradeoff between large packet delay, partially due to collisions between SUs, and high-energy consumption spent for sensing the occupation of licensed channels. To overcome this problem, we take into account packet delay and energy consumption into our framework. Due to the partial spectrum sensing, we use a Partial Observable Stochastic Game (POSG) formalism, and we analyze the existence and some properties of the Nash equilibrium using a Linear Program (LP). We identify a paradox: when licensed channels are more occupied by PUs, this may improve the spectrum utilization by SUs. Based on this observation, we propose a Stackelberg formulation of our problem where the network manager may increase the occupation of licensed channels in order to improve the SUs average throughput. We prove the existence of a Stackelberg equilibrium and we provide some simulations that validate our theoretical findings.
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Date:27/03/2013, 14h - 15h
Room:LINCS, when = 14h
Talk:Inauguration of the Doctorate School, EIT ICT Labs
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Date:20/03/2013, 14h - 15h
Room:LINCS Salle de Conseil
Speaker:Paul Keeler, INRIA/ENS
Talk:Capturing the SINR in cellular networks with Poisson processes
Abstract:The steady rise of user-traffic in wireless cellular networks has resulted in the need for developing robust and accurate models of various performance metrics. A key metric of these networks is the signal-to-interference-and-noise-ratio (SINR) experienced by a typical user. For tractability, often the positions of base stations in such networks are modelled by Poisson point processes whereas actual deployments often more resemble lattices (e.g. hexagonal). Strikingly, under log-normal shadowing it has been observed that the SINR experienced by a typical user is more accurate in a Poisson model than a hexagonal model. In this talk we seek to explain this interesting observation by way of a convergence result. Furthermore, we present numerically tractable, explicit integral expressions for the distribution of SINR of a cellular network modelled by Poisson process. Our model incorporates a power-law path-loss model with arbitrarily distributed shadowing. The results are valid in the whole domain of SINR and, unlike previous methods, do not require the inversion of Laplace transforms.Based on joint work in collaboration with B. Blaszczyszyn and M.K. Karray.
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Date:14/03/2013, 14h
Room:46 rue Barrault, C48
Speaker:Petr Kuznetsov
Talk:On the Benefits of Being Optimistic and Relaxed
Abstract:It seems to be widely accepted that designing correct and highlyconcurrent software is a sophisticated task that can only be held byexperts. A crucial challenge is therefore to convert sequential codeproduced by a mainstream programmer into concurrent one. Usingsynchronization techniques, such as locks or transactional memory, wetackle the problem of wrapping a sequential implementation into a highlyconcurrent one that looks sequential to every thread.We evaluate the amount of concurrency provided by the resultingimplementations via the set of schedules (interleavings of steps of thesequential code) they accept. We start with two synchronizationtechniques: pessimistic and relaxed on the one hand (such as ne-grainedlocking) and optimistic and strongly consistent on the other hand (suchas conventional transactional memories). We show that they areincomparable in that each one may accept schedules not accepted by theother. However, we show that the combination of relaxed consistency andoptimism strictly supersedes both pessimistic and strongly consistentapproaches.
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Date:13/03/2013, 14h - 15h
Room:LINCS Salle de Conseil
Speaker:Masha Frolkova (CWI, Amsterdam)
Talk:Fluid limit approximations of bandwidth-sharing networks with rate constraints
Abstract:Bandwidth-sharing networks, as introduced by Massoulie & Roberts (1998), model the dynamic interaction among an evolving population of elastic flows that compete for several links. The main area of application of such models is telecommunications media, e.g. Internet congestion control. With policies based on optimization procedures, bandwidth-sharing networks are of interest both from a Queueing Theory and Operations Research perspective.In this work, we focus on the regime when link capacities and arrival rates are of a large order of magnitude compared to transfer rates of individual flows, which is standard in practice. Bandwidth-sharing networks are rather complicated systems (we operate with measure-valued processes to study them), and under general structural and stochastic assumptions they resist exact analysis. So we resort to fluid limit approximations. Under general assumptions, we derive the fluid limit for the network evolution in the entire time horizon (extending the corresponding result by Reed and Zwart (2010) for Markovian assumptions). Also, for a wide class of networks, we develop polynomial-time computable fixed-point approximations for their stationary distributions.
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Date:06/03/2013, 14h - 15h
Room:LINCS, Salle du Conseil
Speaker:Giovanni Pau (LIP6)
Talk:V-NDN: Vehicular Named Data
Abstract:In near future, a car will be equipped with a variety sensors and wireless interfaces such as 3G/LTE, WiMAX, WiFi, or DSRC/WAVE. Our vision is to enable vehicles to communicate with each other and with the infrastructure over any and all physical communication channels, as soon as any channel comes into existence and as long as it is available. Although over the years many research papers have been published for automotive research, in reality by and large today's vehicles are connected only through cellular networks to centralized servers. Automotive research such as ad-hoc networking and delay tolerant networking are still far from completion and less likely to deploy. We believe the root cause of this insoluble problem in networking vehicles is IP's communication model, where IP creates its own name space, the IP address space, assigns IP addresses to every communicating end point, and then encapsulates each piece of application data into an IP packet. This whole process insulates applications from data delivery layer. Taking the named-data networking (NDN) as the starting point, we are developing V-NDN, a single framework to realize our vision. NDN identifies named data as the focal point in communication. Utilizing the fact that all data communications happen within established application context, and that nodes running the same applications decide what data they want to get, NDN lets individual nodes to request the desired data using application data names directly. Data names are from applications, they identify data directly; they exist once applications are running, independent from time-varying connectivity in an ad hoc environment. This enable data to exist in the absence of connectivity, and to be exchanged over any physical connectivity once it comes into existence.We have designed and developed V-NDN and demonstrated that our design indeed allowed vehicles to utilize all available channels to communicate; they can effectively communicate with centralized servers as well as with each other to exchange application data in completely ad hoc manner. In this talk we will go over the design choices and the preliminary results from our deployment.
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Date:27/02/2013, 14h - 15h
Room:LINCS; salle de conseil
Speaker:Diego Perino (Alcatel Lucent Bell Labs)
Talk:On the design of architectures and algorithms to support content-oriented functionalities in high speed network equipments.
Abstract:The integration of content oriented functionalities in network equipments is of critical importance for the deployment of future content delivery infrastructures. However, as todayu2019s high-speed network equipments are mostly designed to carry traffic from one location of the network to another by means of IP address information, this integration imposes severe changes to hardware and software technologies. In this talk we focus on system design and evaluation of the basic building blocks enabling content-oriented communication primitives in network equipments. Specifically, we present challenges and solutions to realize name-based forwarding, packet-level storage management and content-based temporary state at high speed. Finally, we briefly introduce our on-going work on the implementation of our solutions on high-speed hardware and software platforms, and on the evolution of our designs to support enhanced content-oriented mechanisms.
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Date:13/02/2013, 14h - 15h
Room:LINCS; salle de conseil
Speaker:Marc Lelarge (INRIA)
Talk:Universality and Phase Transition in Compressed Sensing.
Abstract:I will start with an introduction on compressed sensing. Then I will talk about approximate message passing algorithms and their connection to the universality of a certain phase transition arising in polytope geometry and compressed sensing. Joint work with M. Bayati and A. Montanari (Stanford)
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Date:06/02/2013, 14h - 15h
Room:LINCS, salle de conseil
Speaker:Simon Perreault (Viagenie)
Talk:IPv6 Migration and Carrier-Grade NAT (CGN)
Abstract:IPv4 address exhaustion triggered two parallel efforts: the migration to IPv6, and the deployment of IPv4 service continuity technologies, for the most part based on Carrier-Grade NAT. This talk will provide a broad overview of the current situation with IPv6 migration, will explain what the major actors are currently doing, and will try to provide some insight about the future. In particular, CGN and its impacts will be examined. Related standardization efforts will be discussed as well.
Biography:Simon Perreault is a network engineering consultant with Viag�nie, a Canadian firm.
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Date:30/01/2013, 14h - 15h
Room:LINCS, salle de conseil
Speaker:Isabel Amigo (Telecom Bretagne)
Talk:A Pricing Mechanism and Revenue Sharing in Network Service Providers Alliances
Abstract:Network Service Providers alliances are envisioned to emerge in the near future as a means of selling end-to-end quality assured services through interdomain networks. Several aspects of such a community must be discussed in order to assure its economical and technical viability. Within the economic ones, pricing and revenue sharing are key aspects on which all alliance's members must agree. In this context, we present a framework where services are sold via first-price auctions and incomes are formulated as the solution of a Network Utility Maximization problem. Then, we discuss the revenue sharing problem in such context, express the desirable properties of a revenue sharing method, argue why the existing methods are not suitable, and propose a family of solutions.
Biography:Isabel Amigo was born in January 23th, 1984 in Montevideo, Uruguay. Since 2007 she holds a degree in Electrical Engineering from Universidad de la Rep�blica, Uruguay. Since 2006 she is a Research and Teaching assistant at the Electrical Engineering department of the School of Engineering, Universidad de la Rep�blica, Uruguay. In late 2007 she joins the technical team of the National digital inclusion plan Plan Ceibal , where she is later on in charge of the Projects department and the Research and Development area. On March 2010 she leaves Plan Ceibal in order to pursue a PhD thesis. She is currently a PhD candidate at Telecom Bretagne (France) and Universidad de la Rep�blica (Uruguay), in a co-advised program, under the advisory of Prof. Sandrine Vaton and Prof. Pablo Belzarena.
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Date:16/01/2013, 14h - 15h
Room:LINCS, salle de conseil
Speaker:M. Feuillet, F. Contat, G. Valadon (ANSSI)
Talk:French Internet resilience
Abstract:The French Network and Information Security Agency (FNISA) and theFrench Network Information Center (AFNIC) have recently published adetailed report on the French Internet resilience. This documentis based on measures performed for two key protocols for the Internet :Border Gateway Protocol (BGP) and Domain Name System (DNS).In order to evaluate the resilience of BGP, several indicators have beenused:(i) the correct declaration of routing information to regional informationregistries which is necessary to check messages received by routers;(ii) the connectivity between operators in order to evaluate the risk ofa full disconnection;(iii) the frequency of prefix hijacking by which an operator announces orrelays illegitimate routing information.In order to estimate this indicators, the FNISA has analyzed all BGPmessages of four major French network operators over a period of 11 months.Concerning the DNS protocol, the considered indicators are:(i) the distribution of name servers among countries and operators;(ii) the number of unpatched servers still vulnerable to the Kaminskyvulnerability;(iii) the deployment of protocols such as IPv6 and DNS Security Extensions(DNSSEC).Measures have been performed in two ways: active measures on DNS serversof .fr domains and passive measures by observing the traffic onauthoritative servers of .fr administrated by AFNIC.The aim of this talk is to present the results of this first report andto introduce the new indicators and results which have been obtainedsince then. In the same time, we will introduced several opentheoritical problems linked to this study.
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Date:19/12/2012, LINCS Salle de Conseil
Speaker:Marc Crovella (Boston University)
Talk:Better routing with hyperbolic geometry
Abstract:In the constant search for simple and efficient routing algorithms,a particularly attractive approach is greedy routing: every nodeis assigned a coordinate, and routing consists of simply forwarding tothe neighbor closest to the destination. Unfortunately, in our(Euclidean) world, this strategy is prone to failure. In this talkI will describe how a small change -- working in Hyperbolic space insteadof Euclidean space -- allows one to guarantee that greedy routing is alwayssuccessful.I will review the properties of hyperbolic space for this problem, andthen describe how to use it for provably successful greedy routing on a staticgraphs.Next I will describe how to extend this approach to growing graphs.Finally,I will discuss strategies to make this sort of routing efficient -- that,toensure that paths through the network are short.This is joint work with Andrej Cvetkovski
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Date:05/12/2012, LINCS Salle de Conseil
Speaker:Admela Jukan (Technische Universitat Braunschweig)
Talk:Next Steps towards IP-optical Service Convergence: A Network Management Perspective
Abstract:Despite the steady and significant increase in Internet traffic, today's Internet topologies are stable, reliable, and - underutilized. This is mainly due to the proven ISP practice to overprovision IP links, - often up to seventy percent, thus allowing for accommodation of unpredictable flows, while keeping the network stable and resilient against attacks and failures. Even with major benefits, the practice of overprovision leads to high capital and operational expenses, as well as higher energy consumption. At first glance, dynamic optical circuits can address the downsides: optical circuits can be setup to bypass any congested or faulty IP links and are one of the "greenest" technologies. However, the two networks -- optical and Internet, have evolved as two fundamentally different and separately managed systems, and cannot easily operate in harmony. In this talk, I will discuss why past approaches to deploy dynamic optical circuits have not been widely adopted for IP routing, - from the point of view of network management, and present our research ideas on how Internet can effectively use optical circuits. I will talk about the importance of new systems research and present new directions in theoretical studies in this field, and also give a practical outlook from our EU Project ONE (http://www.ict-one.eu).
Biography:Admela Jukan received the M.Sc. degree in Information Technologies from the Politecnico di Milano, Italy, and the Dr. techn. degree (cum laude) in Electrical and Computer Engineering from the Technische Universitt Wien, Austria. She received her Dipl. -Ing. degree from the Fakultet Elektrotehnike i Racunarstva (FER), in Zagreb, Croatia.She is Chair Professor of Communication Networks in Electrical and Computer Engineering Department at the Technische Universitt Braunschweig in Germany. Prior to coming to TU Braunschweig, she was research faculty at the Institut National de la Recherche Scientifique (INRS), University of Illinois at Urbana Champaign (UIUC) and Georgia Tech (GaTech). In 1999 and 2000, she was a visiting scientist at Bell Labs, Holmdel, NJ. From 2002-2004, she served as Program Director in Computer and Networks System Research at the National Science Foundation (NSF) in Arlington, VA. Dr. Jukan serves as Associate Technical Editor for IEEE Communications Magazine and IEEE Network. She is a co-Editor in Chief of the Elsevier Journal on Optical Switching and Networking (OSN). She is an elected Vice Chair of the IEEE Optical Network Technical Committee, ONTC (Chair in 2014). She currently coordinates a collaborative EU project ONE, focusing on network management convergence of optical networks and the Internet. She is recipient of an Award of Excellence for the BMBF/CELTIC project "100Gb Ethernet" and was also awarded the IBM Innovation Award for applications of parallel computing for rich digital media distribution over optical networks.
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Date:28/11/2012, LINCS Salle de Conseil
Speaker:Alexander Pelov (Telecom Bretagne)
Talk:A network-centric point of view on Smart Grids
Abstract:The Smart Grid is the evolution of this complex network, with one of the major factors being the integration of Machine-to-Machine type communications in every element of this network. This talk will concentrate on presenting the ongoing and future projects related to Smart Grids in Telecom Bretagne, such as networking protocols for Home Area Networks (HAN) and Neighborhood Area Networks (NAN).
Biography:Alexander Pelov is an Associate Professor of Computer Networks in the "Networking, Multimedia and Security" department at the Graduate Engineering School Telecom Bretagne, France. His research focuses on networking protocols for Machine-to-Machine communications, energy efficiency in wireless networks, and protocols and algorithms for Smart Grid applications, most notably related to Smart Meters, sub-metering and Electrical Vehicles. He received his M.Sc. (2005) from the University of Provence, France and Ph.D. (2009) from the University of Strasbourg, France, both in Computer Science.
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Date:21/11/2012, LINCS Salle de Conseil
Speaker:Alexandre Proutiere (KTH and INRIA)
Talk:Iterative Power Packing for Distributed Multiple Access in Wireless Networks
Abstract:We address the problem of designing distributed Multiple Access Control algorithms for wireless networks under the SINR interference model. In the proposed framework, time is divided into frames consisting of a fixed number of slots, and transmitters may adapt the power levels used in the various slots. We aim at developing fully distributed multiple access algorithms that are throughput-optimal in the sense that they perform as well as centralized scheduling algorithms. These algorithms based on a simple power control mechanism, referred to as Power Packing. This mechanism allows each transmitter to tune their power levels in the different slots so as to achieve a target rate while minimizing the number of slots actually used. The proposed algorithms are throughput-optimal, simple and do not require any message passing: each transmitter adapts its power levels depending on the observed interference levels in the various slots. We illustrate the efficiency of our algorithms using numerical experiments.
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Date:14/11/2012, LINCS Salle de Conseil
Speaker:Alonso Silva (Alcatel Lucent Bell Labs)
Talk:Auctions of Licensed vs Unlicensed Use of Spectrum
Abstract:Auctions have regained interest from researchers due to its differentnew applications (Google AdWords auctions, cloud computing auctions,privacy auctions, and white spaces spectrum auctions). In this work inparticular we explore auctions for spectrum that can be allocatedeither to a single bidder (for licensed use) or to a collection ofbidders (for unlicensed use). In this auction, a number of individualbidders all try to get the spectrum for their exclusive use and agroup of other bidders try to get the spectrum for their collectiveuse. The objective is to study these auctions and compare theirdifferent properties.
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Date:24/10/2012, LINCS Salle de Conseil
Speaker:Mohan Dhawan
Talk:A Browser-based Network Measurement Platform
Abstract:For analyzing network performance issues, there can be great utility in having the capability to measure directly from the perspective of end systems. Because end systems do not provide any external programming interface to measurement functionality, obtaining this capability today generally requires installing a custom executable on the system, which can prove prohibitively expensive. In this work we leverage the ubiquity of web browsers to demonstrate the possibilities of browsers themselves offering such a programmable environment. We present Fathom, a Firefox extension that implements a number of measurement primitives that enable websites or other parties to program network measurements using JavaScript. Fathom is lightweight, imposing < 3.2% overhead in page load times for popular web pages, and often provides 1 ms timestamp accuracy. We demonstrate Fathom's utility with three case studies: providing a JavaScript version of the Netalyzr network characterization tool, debugging web access failures, and enabling web sites to diagnose performance problems of their clients.
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Date:17/10/2012, LINCS Salle de Conseil
Speaker:George Kesidis (Pennsylvania State University)
Talk:Sequential Anomaly Detection in a Batch with Growing Number of Tests: Application to Network Intrusion Detection
Abstract:For high (N)-dimensional feature spaces, we consider detection of an unknown, anomalous class of samples amongst a batch of collected samples (of size T), under the null hypothesis that all samples follow the same probability law. Since the features which will best identify the anomalies are a priori unknown, several common detection strategies are: 1) evaluating atypicality of a sample (its p-value) based on the null distribution defined on the full N-dimensional feature space; 2) considering a (combinatoric) set of low order distributions, e.g., all singletons and all feature pairs, with detections made based on the smallest p-value yielded over all such low order tests. The first approach relies on accurate estimation of the joint distribution, while the second may suffer from increased false alarm rates as N and T grow. Alternatively, inspired by greedy feature selection commonly used in supervised learning, we propose a novel sequential anomaly detection procedure with a growing number of tests. Here, new tests are (greedily) included only when they are needed, i.e., when their use (on currently undetected samples) will yield greater aggregate statistical significance of (multiple testing corrected) detections than obtainable using the existing test cadre. Our approach thus aims to maximize aggregate statistical significance of all detections made up until a finite horizon. Our method is evaluated, along with supervised methods, for a network intrusion domain, detecting Zeus bot command-and-control (i.e., intrusion) packet flows embedded amongst (normal) Web flows. It is shown that judicious feature representation is essential for discriminating Zeus from Web. This work in collaboration with D.J. Miller and F. Kocak.
Biography:George Kesidis received his M.S. and Ph.D. in EECS from U.C. Berkeley in 1990 and 1992 respectively. He was a professor in the E&CE Dept of the University of Waterloo, Canada, from 1992 to 2000. Since 2000, he has been a professor of CSE and EE at the Pennsylvania State University. His research, including several areas of computer/communication networking and machine learning, has been primarily supported by NSERC of Canada, NSF and Cisco Systems URP. He served as the TPC co-chair of IEEE INFOCOM 2007 among other networking and cyber security conferences. He has also served on the editorial boards of the Computer Networks Journal, ACM TOMACS and IEEE Journal on Communications Surveys and Tutorials. Currently, he is an Intermittent Expert for the National Science Foundation's Secure and Trustworthy Cyberspace (SaTC) program. His home page is http://www.cse.psu.edu/~kesidis
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Date:10/10/2012, LINCS Salle de Conseil
Speaker:Philippe Jacquet (Alcatel Lucent Bell Labs)
Talk:Joint complexity of short texts or how to spy Twitter
Abstract:Twitter produces several millions of short texts per hour. Monitoring information tendencies has become a key business. In particular the content provider can detect in advance which movie will be popular and move it toward proxies before it is too late (ie causes a network/server congestion). In this talk we present the analysis of short texts via joint complexity. The joint complexity of two texts is the number of distinct factors common to both texts. When the source models of the texts are close then the joint complexity is higher. This technique is applied to DNA sequence analysis because it has a very low overhead. It can now be applied to short text analysis thanks to more accurate theoretical estimate. In particular we show new theoretical results when the sources that generate the texts are Markovian of finite order, a model that particularly fits well with text generation. Joint work with W Szpankowski, D Milioris, B. Berde.
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Date:03/10/2012, LINCS Salle de Conseil
Speaker:Anastasios Giovanidis (INRIA)
Talk:How much do we benefit from cooperation between pairs of neighbouring base stations
Abstract:In the current work we deal with the problem of base station cooperation in the downlink of infinite wireless cellular networks.The positions of base stations are modeled by a Poisson point process. Each base station can choose to cooperate or not with exactly oneof its Delaunay neighbours in order to provide service to a user located within its cell. The cooperation protocol uses a variation of the so-called Willems' encoderand a fixed total transmission power per user is considered.We analytically derive closed form expressions for the coverage probability and we determine the optimal cooperation zones in the network.Numerical evaluation shows benefits in coverage, compared to the common cellular architecture. These however are not very high due to thedeterioration in SINR caused by increased outer-cell total interference. Joint work with F. Baccelli.
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Date:28/09/2012, 14h-15h
Speaker:Tova Milo (Université de Tel Aviv)
Talk:Making Collective Wisdom Wiser
Abstract:Many popular sites, such as Wikipedia and Tripadvisor, rely on public participation to gather information---a process known as crowd data sourcing. While this kind of collective intelligence is extremely valuable, it is also fallible, and policing such sites for inaccuracies or missing material is a costly undertaking. In this talk we will examine how database technology can be put to work to effectively gather information from the public, efficiently moderate the process, and identify questionable input with minimal human interaction. We will consider the logical, algorithmic, and methodological foundations for the management of large scale crowd-sourced data as well as the the development of applications over such information.
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Date:19/09/2012, 14h-15h
Room:Salle du conseil
Speaker:Franois Durand (LINCS / Inria)
Talk:Towards less Manipulable Voting Systems
Abstract:Voting systems can be used in any situation where several entities are to make a decision together. However, the sincere vote may lead to a situation that is not a generalized Nash equilibrium: a group of electors can hide their sincere preferences in order to change the outcome to a candidate they prefer. In that case, we say that the situation is manipulable (i.e. susceptible to tactical voting). Gibbard-Satterthwaite theorem (1973) states that for 3 candidates and more, all voting systems but dictatorship are vulnerable to manipulation. So we would like to know, amongst "reasonable" voting systems, which ones are manipulable with a probability as little as possible. We show that, under quite weak assumptions on the meaning of "reasonable", such optimal voting systems can be found in the class of systems that depend only on the electors' preorders of preferences over the candidates and meet Condorcet criterion.
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Date:12/09/2012, LINCS Salle de Conseil
Speaker:Siu-Wai Ho (University of South Australia)
Talk:Error Free Perfect Secrecy Systems
Abstract:Shannon's fundamental bound for perfect secrecy stated that the entropy of the secret message U cannot be larger than the entropy of the secret key R shared by the sender and the legitimated receiver. Massey gave an information-theoretic proof of this result and the proof did not require U and R to be independent. By adding an extra assumption that I(U;R) = 0, we show a tighter bound on H(R) in this talk. Our bound states that the logarithm of the message sample size cannot be larger than the entropy of the secret key. We also consider the case that a perfect secrecy system is used multiple times. A new parameter, namely expected key consumption, is defined and justified. We show the existence of a fundamental trade-off between the expected key consumption and the number of channel uses for transmitting a cipher-text. A coding scheme, which is optimal under certain conditions, is introduced.
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Date:10/09/2012, 14h - 15h
Room:LINCS, Salle de Conseil
Speaker:Lixia Zhang (UCLA)
Talk:Evolving Internet into the Future via Named Data Networking
Abstract:While the Internet has succeeded far beyond expectations, thesuccess has also stretched its initial design assumptions. Sinceapplications operate in terms of data and more end points becomemobile, it becomes increasingly difficult and inefficient to satisfyIP's requirement of determining exactly where (at which IP address)to find desired data. The Named Data Networking project aims tocarry the Internet into the future through a conceptually simple yettransformational architecture shift, from today's focus on where --addresses and hosts -- to what -- the data that users andapplications care about. In this talk I will present the basicdesign of NDN and our initial results.
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Date:05/09/2012, LINCS Salle de Conseil
Speaker:Wojciech Szpankowski (Purdue University)
Talk:NSF Center for Science of Information: An Overview
Abstract:Information is the distinguishing mark of our era, permeating everyfacet of our lives. An ability to understand and harness information hasthe potential for significant advances. Our current understanding ofinformation dates back to Claude Shannon's revolutionary work in 1948,resulting in a general mathematical theory of reliable communicationthat not only formalized the modern digital communication and storageprinciples but also paved the way for the Internet, DVDs and iPods of today.While Shannon's information theory has had profound impact, its applicationbeyond storage and communication poses foundational challenges. In 2010the National Science Foundation established the Science & TechnologyCenter for the Science of Information to meet the new challenges posed bythe rapid advances in networking, biology and knowledge extraction.Its mission is to advance science and technology through a newquantitative understanding of the representation, communication andprocessing of information in biological, physical, social and engineeringsystems. Purdue University leads nine partner institutions: Berkeley,Bryn Mawr, Howard, MIT, Princeton, Stanford, Texas A&M, UCSD, and UIUC(cf. http://cacm.acm.org/magazines/2011/2/104389-information-theory-after-shannon/fulltext).In this talk, after briefly reviewing main results of Shannon,(cf. http://cacm.acm.org/magazines/2011/2/104389-information-theory-after-shannon/fulltext).In this talk, after briefly reviewing main results of Shannon,we attempt to identify some features of informationencompassing structural, spatio-temporal, and semantic facets ofinformation. We present two new results: One on a fundamentallower bound for structural compression and a novel algorithmachieving this lower bound for graphical structures.Second, on the problem of deinterleaving Markov processes overdisjoint finite alphabets, which have been randomlyinterleaved by a finite-memory switch.
Biography:Wojciech Szpankowski is Saul Rosen Professor of Computer Science and(by courtesy) Electrical and Computer Engineering at Purdue Universitywhere he teaches and conducts research in analysis of algorithms,information theory, bioinformatics, analytic combinatorics, random structures,and stability problems of distributed systems.He received his M.S. and Ph.D. degrees in Electrical and ComputerEngineering from Gdansk University of Technology.He held several VisitingEngineering from Gdansk University of Technology.He held several VisitingProfessor/Scholar positions, including McGill University, INRIA, France,Stanford, Hewlett-Packard Labs, Universite de Versailles, University ofCanterbury, New Zealand, Ecole Polytechnique, France, and the Newton Institute,Cambridge, UK. He is a Fellow of IEEE, and the Erskine Fellow.In 2010 he received the Humboldt Research Award.In 2001 he published the book "Average Case Analysis ofAlgorithms on Sequences", John Wiley & Sons, 2001.He has been a guest editor and an editor of technicaljournals, including Theoretical Computer Science, theACM Transaction on Algorithms, the IEEE Transactions onInformation Theory, Foundation and Trendsin Communications and Information Theory,Combinatorics, Probability, and Computing, and Algorithmica.In 2008 he launched the interdisciplinary Institute for Science ofInformation, and in 2010 he became the Director of the newly established NSFScience and Technology Center for Science of Information.
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Date:24/07/2012, Amphi Estaunie'
Speaker:Ian F. Akyildiz (Georgia Institute of Technology)
Talk:Nanonetworks: A New Frontier in Communication
Abstract:Nanotechnology is enabling the development of devices in a scale ranging from one to a few one hundred nanometers. Nanonetworks, i.e., the interconnection of nano-scale devices, are expected to expand the capabilities of single nano-machines by allowing them to cooperate and share information. Traditional communication technologies are not directly suitable for nanonetworks mainly due to the size and power consumption of existing transmitters, receivers and additional processing components. All these define a new communication paradigm that demands novel solutions such as nano-transceivers, channel models for the nano-scale, and protocols and architectures for nanonetworks. In this talk, first the state-of-the-art in nano-machines, including architectural aspects, expected features of future nano-machines, and current developments are presented for a better understanding of the nanonetwork scenarios. Moreover, nanonetworks features and components are explained and compared with traditional communication networks. Novel nano-antennas based on nano-materials as well as the terahertz band are investigated for electromagnetic communication in nanonetworks. Furthermore, molecular communication mechanisms are presented for short-range networking based on ion signaling and molecular motors, for medium-range networking based on flagellated bacteria and nanorods, as well as for long-range networking based on pheromones and capillaries. Finally, open research challenges such as the development of network components, molecular communication theory, and new architectures and protocols, which need to be solved in order to pave the way for the development and deployment of nanonetworks within the next couple of decades are presented.%
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Date:20/07/2012, LINCS Salle de Conseil
Speaker:Dave Tath
Talk:Controlling Queue Delay
Abstract:Nearly three decades after it was first diagnosed, the persistently full buffer problem, recently exposed as part of bufferbloat is still with us and made increasingly critical by two trends. First, cheap memory and a more is better mentality have led to the inflation and proliferation of buffers. Second, dynamically varying path characteristics are much more common today and are the norm at the consumer Internet edge. Reasonably sized buffers become extremely oversized when link rates and path delays fall below nominal values.The solution for persistently full buffers, AQM (active queue management), has been known for two decades but has not been widely deployed because of implementation difficulties and general misunderstanding about Internet packet loss and queue dynamics. Unmanaged buffers are more critical today since buffer sizes are larger, delay-sensitive applications are more prevalent, and large (streaming) downloads common. The continued existence of extreme delays at the Internet edge can impact its usefulness and hamper the growth of new applications.This article aims to provide part of the bufferbloat solution, proposing an innovative approach to AQM suitable for today Internet called CoDel (for Controlled Delay,). This is a no-knobs AQM that adapts to changing link rates and is suitable for deployment and experimentation in Linux-based routers (as well as silicon). This talk was given about a week before by Van Jacobson at IETF84 (see http://recordings.conf.meetecho.com/Recordings/watch.jsp
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Date:18/07/2012, 14h - 15h
Room:LINCS, Salle de Conseil
Speaker:Yoram Haddad (Jerusalem College of Technology and Ben-Gurion University)
Talk:SINR Diagram and their application to Interference Cancellation
Abstract:In this talk we will first present what is a SINR diagram and why it is important to the design of efficient algorithms for wireless networks. Then we will discuss the reception zones of a wireless network in the SINR model with receivers that employ interference cancellation (IC). IC is a recently developed technique that allows a receiver to decode interfering signals, and cancel them from the received signal in order to decode its intended message. We first derive the important topological properties of the reception zones and their relation to high-order Voronoi diagrams and other geometric objects. We then discuss the computational issues that arise when seeking an efficient description of the zones. Our main fundamental result states that although potentially there are exponentially many possible cancellation orderings, and as a result, reception zones, in fact there are much fewer nonempty such zones. We prove a linear bound (hence tight) on the number of zones and provide a polynomial time algorithm to describe the diagram. Moreover, we introduce a novel parameter, the Compactness Parameter, which influences the tightness of our bounds. We then utilize these properties to devise a logarithmic time algorithm to answer point-location queries for networks with IC.This work was published in the Proceedings of the 23rd Annual ACM-SIAM Symposium on Discrete Algorithms (SODA'12). Join work with: Chen Avin, Asaf Cohen, Erez Kantor, Zvi Lotker, Merav Parter and David Peleg.
Biography:Yoram Haddad received his BSc, Engineer diploma and MSc (Radiocommunications) from SUPELEC in 2004 and 2005, and his PhD in computer science and networks from Telecom ParisTech in 2010. Since 2010 he is a tenure-track senior lecturer (Assistant Professor) at the Jerusalem College of Technology (JCT) in Jerusalem, Israel. In parallel, since 2011 he is a post-doctoral research associate at the Ben-Gurion University (BGU) in Beer-Sheva, Israel.Yoram's main research interests are in the area of Wireless Networks and Algorithms for networks. He is specifically interested in energy efficient wireless deployment, Femtocell, modeling of wireless networks, wireless application to Intelligent Transportation Systems (ITS) and more recently Wireless Software Defined Networks (SDN).
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Date:11/07/2012, 14h-16h
Room:LINCS, Salle de Conseil.
Talk:postoponed to september!! --ACM SIGCOMM Information Centric Networking (ICN) preview talks--
Abstract:Note: the seminar has been postponed to september -- sorry for the inconvenience
  • Exploit the known or explore the unknown: Hamlet-like doubts in ICN, byRaffaele Chiocchetti, Dario Rossi, Giuseppe Rossini, Giovanna Carofiglio, Diego Perino.
  • Joint Hop-by-Hop and Receiver-Driven Interest Control Protocol for Content-Centric Networks, by Giovanna Carofiglio, Massimo Gallo and Luca Muscariello
  • Caesar: a Content Router for High Speed Forwarding, byMatteo Varvello, Diego Perino and Jairo Esteban
  • ICN-RE: Redundancy Elimination for Information-Centric Networking , byDiego Perino, Matteo Varvello and Krishna P. N. Puttaswamy
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    Date:10/07/2012, 2:30pm-3:30pm
    Room:Amphi Saphir
    Speaker:Fr'ed'eric Cuppens et Nora Cuppens-Boulahia (T'el'ecom Bretagne)
    Talk:Expression, D'eploiement, Analyse et Administration de Politiques de S'ecurit'e
    Abstract:La s'ecurit'e des syst`emes d'information repose sur la conception de composants ayant pour objectif d'assurer la protection de ces syst`emes contre les diff'erentes attaques potentielles. Aujourd'hui, de nombreux composants de s'ecurit'e logiciels ou mat'eriels sont disponibles tels que les protocoles cryptographiques, les infrastructures de gestion de cl'es publiques (PKI), les pare-feux, les contr^leurs d'acc`es aux syst`emes d'exploitation et aux applications, les syst`emes de d'etection d'intrusion (IDS) et les m'ecanismes anti-viraux. Cependant, pour que ces diff'erents composants de s'ecurit'e soient efficaces, il convient de d'efinir une politique de s'ecurit'e globale au syst`eme d'information `a prot'eger. Il faut ensuite appliquer une m'ethodologie formelle permettant de configurer ces diff'erents composants. Actuellement, une telle m'ethodologie n'existe pas et les administrateurs de s'ecurit'e sont oblig'es de configurer manuellement et s'epar'ement les diff'erents composants de s'ecurit'e. Outre les probl`emes d'incoh'erence, les risques d'erreur sont de deux types : configuration trop restrictive ne permettant pas aux utilisateurs autoris'es de r'ealiser les activit'es dont ils ont le responsabilit'e ou bien politique de s'ecurit'e trop permissive cr'eant des failles de s'ecurit'e. Dans ce contexte, nous montrerons comment apporter des solutions innovantes et efficaces aux probl`emes suivants: Expression formelle de politiques de s'ecurit'e; D'eploiement de politiques de s'ecurit'e; Analyse de politiques de s'ecurit'e; Administration de politiques de s'ecurit'e; R'eaction aux intrusions bas'ee sur le red'eploiement de la politique. Nous nous int'eressons 'egalement aux nouvelles approches pour externaliser et mutualiser des donn'ees en pr'eservant les exigences exprim'ees dans la politique de s'ecurit'e. Lorsque ce ne sont pas les valeurs des attributs qui sont sensibles mais les associations entre ces valeurs, l'id'ee est de partitionner les donn'ees en cassant ces associations et de ne chiffrer certaines donn'ees que lorsque la fragmentation ne suffit pas. Nous discuterons la compl'ementarit'e de cette approche avec diff'erentes propositions actuelles telles que les fonctions de chiffrement homomorphique pour effectuer des calculs (addition, multiplication) sur donn'ees chiffr'ees, ainsi que des primitives de searchable encryption qui permettent de rechercher la pr'esence de mots-cl'es dans des documents chiffr'es.
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    Date:04/07/2012, 14h
    Room:LINCS, Salle de Conseil.
    Speaker:Luigi Rizzo (Univ. of Pisa)
    Talk:netmap: a novel framework for fast packet I/O
    Abstract:Many applications (routers, traffic monitors, firewalls,etc.) need to send and receive packets at line rate even onvery fast links. In this paper we present netmap, a novelframework that enables commodity operating systemsto handle the millions of packets per seconds traversing1..10 Gbit/s links, without requiring custom hardware orchanges to applications.In building netmap, we identified and successfully reducedor removed three main packet processing costs:per-packet dynamic memory allocations, removed bypreallocating resources; system call overheads, amortizedover large batches; and memory copies, eliminatedby sharing buffers and metadata between kerneland userspace, while still protecting access to device registersand other kernel memory areas. Separately, someof these techniques have been used in the past. The noveltyin our proposal is not only that we exceed the performanceof most of previouswork, but also that we providean architecture that is tightly integrated with existing operatingsystem primitives, not tied to specific hardware,and easy to use and maintain.netmap has been implemented in FreeBSD and Linuxfor several 1 and 10 Gbit/s network adapters. In our prototype,a single core running at 900 MHz can send orreceive 14.88 Mpps (the peak packet rate on 10 Gbit/slinks). This is more than 20 times faster than conventionalAPIs. Large speedups (5x and more) are alsoachieved on user-space Click and other packet forwardingapplications using a libpcap emulation library runningon top of netmap.This work received the Best paper award at USENIX ATC 2012
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    Date:28/06/2012, 2pm-3pm
    Room:Amphi Saphir
    Speaker:Prof. Ashwin Gumaste (IIT Bombay)
    Talk:Design, development and deployment of a Ultra-Fast Low-Latency Carrier Ethernet Switch Router
    Abstract:Transport network infrastructures are soon being replaced from legacy SDH/SONET based on packet based that can be seamlessly integrated with optical networks. We present a packet based, carrier-class network architecture, system and communication method that facilitates collapsing multiple Internet layers into a transport element. This Carrier Ethernet Switch router is based on the principle of binary and source routing leading to extremely low energy consumption, low-latency, small foot-print and support emerging services such as mobile backhaul, cloud computing, metro transport and data-center. We discuss the conceptual design, implementation and analysis of this router as well as future roadmap. We will also showcase deployment in a real network and how this can benefit the larger telecommunication community.
    Biography:Ashwin Gumaste is currently the Institute Chair Associate Professor in the Department of Computer Science and Engineering at the Indian Institute of Technology (IIT) Bombay. He is currently also a consultant to Nokia Siemens Networks, Munich where he works on optical access standardization efforts. From 2008-2012 he was also the J. R. Isaac Chair Assistant Professor. He was a Visiting Scientist with the Massachusetts Institute of Technology (MIT), Cambridge, USA in the Research Laboratory for Electronics from 2008 to 2010. He was previously with Fujitsu Laboratories (USA) Inc in the Photonics Networking Laboratory (2001-05). He has also worked in Fujitsu Network Communications R&D (in Richardson TX) and prior to that with Cisco Systems in the Optical Networking Group (ONG). His work on light-trails has been widely referred, deployed and recognized by both industry and academia. His recent work on Omnipresent Ethernet has been adopted by tier-1 service providers and also resulted in the largest ever acquisition between any IIT and the industry. This has led to a family of transport products. Ashwin has 20 granted US patents and over 30 pending patent applications. Ashwin has published about 120 papers in referred conferences and journals. He has also authored three books in broadband networks called DWDM Network Designs and Engineering Solutions (a networking bestseller), First-Mile Access Networks and Enabling Technologies and Broadband Services: User Needs, Business Models and Technologies for John Wiley. Owing to his many research achievements and contributions, Ashwin was awarded the Government of India’s DAE-SRC Outstanding Research Investigator Award in 2010 as well as the Indian National Academy of Engineering’s (INAE) Young Engineer Award (2010). He has served Program Chair, Co-chair, Publicity chair and workshop chair for IEEE conferences and as Program Committee member for IEEE ICC, Globecom, OFC, ICCCN, Gridnets etc. Ashwin is also a guest editor for IEEE Communications Magazine, IEEE Network and the founding Editor of the IEEE ComSoc ONTC’s newsletter Prism. He is the Chair of the IEEE Communication Society's Technical Committee on High Speed Networks (TCHSN) 2011-2013. He has been with IIT Bombay since 2005 where he convenes the Gigabit Networking Laboratory (GNL): www.cse.iitb.ac.in/gnl. The Gigabit Networking Laboratory has secured over 11 million USD in funding since its inception and has been involved in 4 major technology transfers to the industry.
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    Date:26/06/2012, 14h30
    Speaker:Pr. David A. Rosenbaum (Penn State University)
    Talk:Cognition and Action (Joint ACM SiGCHI Paris - INFRES seminar)
    Abstract:For your thoughts to be useful, they must be enacted. This is true even for mundane thoughts like those for getting up out of your chair, leaving your home or office, coming to the room where this talk will be held, making your way to your seat, and settling in to hear about research on the planning and control of everyday actions. The research to be described will draw on evidence from neurophysiology, behavioral science, and computational modeling. A view that all these lines of evidence support is that goal postures are specified before movements are planned and performed. Motor control, you will hear, is more cognitively rich than some have realized. See also: http://paris.sigchi.acm.org/
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    Date:08/06/2012, 10h
    Speaker:FranÁois TaÔani (Lancaster Univ.)
    Talk:Modular Georecommendation In Gossip-Based Social Networks
    Abstract:Geolocated social networks, that combine traditional social networking features with geolocation information, have grown tremendously over the last few years. Yet, very few works have looked at implementing geolocated social networks in a fully distributed manner, a promising avenue to handle the growing scalability challenges of these systems. In this talk, I will focus on georecommendation, and show that existing decentralized recommendation mechanisms perform in fact poorly on geodata. I will present a set of novel gossip-based mechanisms to address this problem, which we have captured in a modular similarity framework called Geology. The resulting platform is lightweight, efficient, and scalable, and I will illustrate its superiority in terms of recommendation quality and communication overhead on a real data set of 15,694 users from Foursquare, a leading geolocated social network.This is joint work with Anne-Marie Kermarrec (INRIA Rennes, France) and Juan M. Tirado (Universidad Carlos III, Spain)
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    Date:06/06/2012, 14h - 15h
    Room:LINCS, Salle du conseil
    Speaker:Mathieu Leconte
    Talk:Bipartite Graph Structures for Efficient Balancing of Heterogeneous Loads
    Abstract:This paper considers large scale distributed content serviceplatforms, such as peer-to-peer video-on-demand systems.Such systems feature two basic resources, namely storageand bandwidth. Their efficiency critically depends on twofactors: (i) content replication within servers, and (ii) howincoming service requests are matched to servers holding requestedcontent. To inform the corresponding design choices,we make the following contributions.We first show that, for underloaded systems, so-called pro-portional content placement with a simple greedy strategyfor matching requests to servers ensures full system efficiencyprovided storage size grows logarithmically with the systemsize. However, for constant storage size, this strategy undergoesa phase transition with severe loss of efficiency assystem load approaches criticality.To better understand the role of the matching strategy inthis performance degradation, we characterize the asymptoticsystem efficiency under an optimal matching policy.Our analysis shows that -in contrast to greedy matching-optimal matching incurs an inefficiency that is exponentiallysmall in the server storage size, even at critical systemloads. It further allows a characterization of content replicationpolicies that minimize the inefficiency. These optimalpolicies, which differ markedly from proportional placement,have a simple structure which makes them implementablein practice.On the methodological side, our analysis of matching performanceuses the theory of local weak limits of randomgraphs, and highlights a novel characterization of matchingnumbers in bipartite graphs, which may both be of independentinterest.ACM SIGMETRICS'12 Preview Talk, joint work by Mathieu Leconte (Technicolor - INRIA), Marc Lelarge (INRIA - Ecole Normale SupÈrieure) and Laurent MassouliÈ (Technicolor)
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    Date:31/05/2012, 2pm-3pm
    Room:Amphi Saphir
    Speaker:Dr Raphael Frank (University of Luxembourg)
    Talk:Improving Highway Traffic through Partial Velocity Synchronization
    Abstract:In this work we address the problem of uncoordinated highway traffic. We first identify the main causes of the capacity drop namely high traffic demand and inadequate driver reaction. In the past, traffic and user behavior have been accurately described by cellular automata (CA) models. In this work we extend the CA model to deal with highway traffic fluctuations and jams. Specifically, the model incorporates the communication layer between vehicles. The model thus enables us to study the impact of inter-vehicular communications and in particular the delivery of critical and timely upstream traffic information on driver reaction. Based on the newly available traffic metrics, we propose an Advanced Driver Assistance System (ADAS) that suggests non-intuitive speed reduction in order to avoid the formation of the so called phantom jams. The results show that using such a system considerably increases the overall traffic flow, reduces travel time and avoid unnecessary slow downs.
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    Date:30/05/2012, 2pm-3pm
    Room:LINCS, Salle du conseil
    Speaker:Alexandre Menai (Akamai)
    Talk:Mobile Web AccelerationChallenges
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    Date:16/05/2012, 2pm-3pm
    Room:LINCS, Salle du conseil
    Speaker:Davide Cuda
    Talk:Distributed Scheduling Algorithm for Asynchronous Input-Queued Switches
    Abstract:nput-queued (IQ) switches are one of the referencearchitectures for the design of high-speed packet switches. Classicalresults in this field refer to the scenario in which the wholeswitch transfers the packets in a synchronous fashion, in phasewith a sequence of fixed-size timeslots, selected to transport aminimum-size packet. However, for switches with large numberof ports and high bandwidth, maintaining an accurate globalsynchronization and transferring all the packets in a synchronousfashion is becoming more and more challenging. Furthermore,variable size packets (as in the traffic present in the Internet)require rather complex segmentation and reassembly processesand some switching capacity is lost due to partial filling oftimeslots. Thus, we consider a switch able to natively transferpackets in an asynchronous fashion thanks to a simple anddistributed packet scheduler. We investigate the performance ofasynchronous IQ switches and show that, despite their simplicity,their performance are comparable or even better than those ofsynchronous switches. These partly unexpected results highlightthe great potentiality of the asynchronous approach for the designof high-performance switches.
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    Date:09/05/2012, 2pm-3pm
    Room:LINCS, Salle du conseil
    Speaker:Dohy Hong (ALU Bell Labs)
    Talk:D-iteration: Asynchronous Distributed Computation
    Abstract:We present a first evaluation of the potential of an asynchronous distributed computation associated to the recently proposed approach, D-iteration: the D-iteration is a fluid diffusion based iterative method, which has the advantage of being natively distributive. It exploits a simple intuitive decomposition of the matrix-vector product as elementary operations of fluid diffusion associated to a new algebraic representation. We show through experiments on real datasets how much this approach can improve the computation efficiency when the parallelism is applied: with the proposed solution, when the computation is distributed over K virtual machines (PIDs), the memory size to be handled by each virtual machine decreases linearly with K and the computation speed increases almost linearly with K with a slope becoming closer to one when the number N of linear equations to be solved increases.
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    Date:03/05/2012, 2pm-3pm
    Room:Amphi Saphir
    Speaker:Ken Christensen
    Talk:Green Networks: Substituting, Consolidation and Scheduling to Save Energy
    Abstract:More than 2% of global carbon emissions can be attributed to ICT.These carbon emissions are expected to increase by a compounded annual growth of 6% until at least 2020. To reduce the level of carbon emissions by reducing energy consumed, we seek for ICT equipment to both reduce its peak poweruse and achieve energy-proportional operation - where the power consumed is proportionalto load and not capacity. Broadly speaking, there are three ways to reduce energy useat the system level : by substituting consolidating and scheduling. As an example ofsubstitution, I will describe work in developing proxies for a range of network protocolsand applications including SIP phones. As an example of scheduling, I will describe work with coalescing of packets in Energy Efficient Ethernet (EEE) and of HTTP requestsfor hybrid web servers. I will end the talk with a discussion of some open problems andnext steps for further reducing energy consumption of both ICT and non-ICT systems focusingon the role of networks.
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    Date:02/05/2012, 2pm-3pm
    Room:LINCS, Salle du conseil
    Speaker:Chandramani Singh (IISc Bangalore)
    Talk:Game-theoretic resource management in cellular networks
    Abstract:We pose a few resource management problems in cellular networks, and propose solutions based on game theory. First, we investigate cooperationamong cellular service providers. We consider networks in whichcommunications involving different base stations do not interfere. Ifproviders jointly deploy and pool their resources, such as spectrum andBSs, and agree to serve each others customers, their aggregate payoffsubstantially increases. The potential of such cooperation can, however,be realized only if the providers intelligently determine who they wouldcooperate with, how they would deploy and share their resources, and howthey would share the aggregate payoff. We assume that the providers canarbitrarily share the aggregate payoff . Then, developing a rational basisfor payoff sharing is imperative for the stability of the coalition. Weaddress these issues by formulating cooperation using the theory of transferable utility coalitional games. I will briefly discuss two other resource allocation problems in cellular networks which are in the context of joint power control, BS association and BS placement in the uplinks of cellular networks.
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    Date:25/04/2012, 2pm-3pm
    Room:LINCS, Salle du conseil
    Speaker:Vincent Toubiana
    Talk:Privacy preference expression
    Abstract:As we are browsing the web we are tracked by ad-networks, social networks and other third parties that build (supposedly) anonymized and incomplete records of users' browsing history. This talk will first discuss the threats resulting from web-tracking by describing how these records can be de-anonymized. Then, we will overview existing solutions to prevent tracking with a focus on the work done in the W3C Tracking Protection group. We will also quickly overview privacy-preserving mechanisms that could be used to support behavioral targeting. In the last part of the talk we will discuss another type of threat: photo tagging on social networks. We will quickly overview the proposed mechanism to protect privacy of pictured persons. Finally we will present Photo-Tagging Preference Enforcement (Photo-TaPE) which helps users to control how their pictures are published on the web.
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    Date:18/04/2012, 2pm-3pm
    Room:LINCS, Salle du conseil
    Speaker:Pedro Maria Santiago del Rio
    Talk:Wire-speed statistical classification of network traffic on commodify hardware
    Abstract:In this paper, we present a software-based traffic classification engine running on off-the-shelf multi-core hardware, able to process in real-time aggregates of up to 15 million packet per second over a single 10Gbps interface.This significant advance with respect to achievable classification rates with respect to the current state of the art is possible due to: (i) the use of PacketShading to efficiently move batches of packet headers from the NIC to the main CPU; (ii) the use of lightweight statistical classification techniques expoiting the size of the first few packets of a flow; (iii) a careful tuning of several aspects of the software application and of the hardware environment.Using both real Tier-1 traces and synthetic traffic, we demonstrate that traffic classification of more than 10Gbps traffic aggregates is feasible with open-source sofware on common hardware.
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    Date:11/04/2012, 2pm-3pm
    Room:LINCS, Salle du conseil
    Speaker:R-M. Indre
    Talk:Towards All-Optical Packet Networks Using Optical Switch-Combiners
    Abstract:We propose a novel manner to perform optical packet switching which does not require any prior electronicsignaling or header processing. The proposed packet switchingscheme can be implemented by means of a new optical deviceable to handle packet contention in the optical domain byimplementing a first-come first-served policy. This simple deviceis based exclusively on off-the-shelf components and can be usedto build optical packet switches, that we refer to as switch-combiners. The latter can in turn be used to build all-opticalpacket networks. Using variants of the Engset model, we analysethe impact of network load on the performance of data traffic.The results are illustrated on the practically interesting cases ofaccess and data center networks. Joint work with T. Bonald, D. Cuda and L. Noirie
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    Date:04/04/2012, 2pm-3pm
    Room:LINCS, Salle du conseil
    Speaker:Timothy G. Griffin (University of Cambridge)
    Talk:Routing in Equilibrium
    Abstract:Some path problems cannot be modelledusing semirings because the associatedalgebraic structure is not distributive. Ratherthan attempting to compute globally optimalpaths with such structures, it may be sufficientin some cases to find locally optimal paths ---paths that represent a stable local equilibrium.For example, this is the type of routing system thathas evolved to connect Internet Service Providers(ISPs) where link weights implementbilateral commercial relationships between them.Previous work has shown that routing equilibria canbe computed for some non-distributive algebrasusing algorithms in the Bellman-Ford family.However, no polynomial time bound was knownfor such algorithms. In this talk, we show thatrouting equilibria can be computed usingDijkstra's algorithm for one class of non-distributivestructures. This provides the firstpolynomial time algorithm for computing locallyoptimal solutions to path problems.This is joint work with Jo„o LuÌs Sobrinho (http://www.lx.it.pt/~jls/)presented at the 19th International Symposium on MathematicalTheory of Networks and Systems (MTNS 2010).You can find the paper here:http://www.cl.cam.ac.uk/~tgg22/publications/routing_in_equilibrium_mtns_2010.pdfTimothy G. Griffin is currently on sabbatical in Paris atPPS/INRIA-pi-r2, http://www.pps.jussieu.frThis file http://www.cl.cam.ac.uk/~tgg22/metarouting/rie-1.0.v is a first cut at formalizing these results using Coq (http://coq.inria.fr)with ssreflect (http://www.msr-inria.inria.fr/Projects/math-components)
    Biography:Thisfileis a first cut at formalizing these results usingCoq with http://www.msr-inria.inria.fr/Projects/math-components">ssreflect.
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    Date:28/03/2012, 14h - 15h
    Speaker:Giacomo Morabito
    Talk:Opportunities and challenges for ICN experimentation and deployment inSoftware Defined Networks
    Abstract:The Information-Centric Networking (ICN) paradigm is expected to beone of the major innovations of the Future Internet.An ICN system can be characterized by some key components like: (i)the content-centric request/reply paradigm for datadistribution, (ii) route-by-name operations, and (iii) in-networkcaching.A crucial problem for all ICN solutions is to identify policies forits experimentation in a real networking environment and its actualdeployment in operating network infrastructures.Software Defined Networking (SDN), which is another topic currentlyattracting increasing attention, may represent a valid solution tosuch a problem.SDN serates the forwarding operations from the network controloperations which may be defined dynamically through software. In thisway, it is extremely simple to introduce novel networking solutions,in operating communication infrastructures, thus increasing network"evolvability".We are currently implementing and testing an ICN approach, named CONET(COntent NETwork), in OFELIA -- a pan-European SDN network platform,based on the OpenFlow technology.This talk will cover our motivations, our expectations and ourfrustrations; in other words the lessons we are learning in such aprocess.
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    Date:21/03/2012, 2pm-onward
    Room:LINCS, Salle du conseil
    Speaker:Manjesh Kumar Hanwal, Diana Joumblatt, Massimo Gallo, Giuseppe Rossini, Natalya Rozhnova
    Talk:INFOCOM preview talks
    Abstract:Preview of talks at INFOCOM 2012 and associated workshop. See individual talks for abstracts and details.
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    Date:21/03/2012, 14h-onward
    Speaker:Manjesh Kumar Hanwal
    Talk:Stochastic Geometry based Medium Access Games
    Abstract:This paper studies the performance of Mobile Ad hoc Networks (MANETs) when the nodes, that form aPoisson point process, selfishly choose their Medium Access Probability (MAP). We consider goodput and delayas the performance metric that each node is interested in optimizing taking into account the transmission energycosts. We introduce a pricing scheme based on the transmission energy requirements and compute the symmetricNash equilibria of the game in closed form. It is shown that by appropriately pricing the nodes, the selfish behaviorof the nodes can be used to achieve the social optimum at equilibrium. The Price of Anarchy is then analyzed forthese games. For the game with delay based utility, we bound the price of anarchy and study the effect of the pricefactor. For the game with goodput based utility, it is shown that price of anarchy is infinite at the price factor thatachieves the global optima.,joint work with E. Altman and F. Baccelli. Full paper is available at http://arxiv.org/pdf/1112.3741.pdf
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    Date:21/03/2012, 14h-onward
    Speaker:Natalya Rozhnova
    Talk:An effective hop-by-hop Interest shaping mechanism for CCN communications
    Abstract:We introduce a rate-based congestion control mechanism for Content-Centric Networking (CCN). It builds on the fact that one Interest retrieves at most one Data packet. Congestion can occur when aggregate conversations arrive in excess and fill up the transmission queue of a CCN router. We compute the available capacity of each CCN router in a distributed way in order to shape their conversations Interest rate and therefore, adjust dynamically their Data rate and transmission buffer occupancy. We demonstrate the convergence properties of this Hop-by-hop Interest Shaping mechanism(HoBHIS) and provide a performance analysis based on various scenariosusing our ns-2 simulation environment. Joint work with Serge Fdida.
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    Date:21/03/2012, 14h-onward
    Speaker:Giuseppe Rossini
    Talk:On sizing CCN content stores by exploiting topological information
    Abstract:In this work, we study the caching performance ofContent Centric Networking (CCN), with special emphasis on thesize of individual CCN router caches. Specifically, we considerseveral graph-related centrality metrics (e.g., betweenness, closeness,stress, graph, eccentricity and degree centralities) to allocatecontent store space heterogeneously across the CCN network, andcontrast the performance to that of an homogeneous allocation.To gather relevant results, we study CCN caching performanceunder large cache sizes (individual content stores of 10 GB),realistic topologies (up to 60 nodes), a YouTube-like Internetcatalog (10^8 files for 1PB video data). A thorough simulationcampaign allow us to conclude that (i) , the gain brought bycontent store size heterogeneity is very limited, and that (ii) thesimplest metric, namely degree centrality, already proves to bea "sufficiently good" allocation criterion.On the one hand, this implies rather simple rules of thumb forthe content store sizing (e.g., "if you add a line card to a CCNrouter, add some content store space as well"). On the otherhand, we point out that technological constraints, such as linespeedoperation requirement, may however limit the applicabilityof degree-based content store allocation. Joint work with D. Rossi
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    Date:21/03/2012, 14h-onward
    Speaker:Massimo Gallo
    Talk:ICP: Design and Evaluation of an Interest Control Protocol for Content-Centric Networking
    Abstract:Content-centric networking (CCN) brings aparadigm shift in the present Internet communication modelby addressing named-data instead of host locations. Withrespect to TCP/IP, the transport model is connectionless witha unique endpoint at the receiver, driving a retrieval processnatively point to multi-point. Another salient feature of CCN isthe possibility to embed storage capabilities into the network,adding a new dimension to the transport problem. The focusof this work is on the design of a receiver-driven Interestcontrol protocol for CCN, whose definition, to the best of ourknowledge, still lacks in literature. ICP realizes a window-basedInterest flow control, achieving full efficiency and fairnessunder proper parameters setting. In this paper, we providean analytical characterization of average rate, expected datatransfer delay and queue dynamics in steady state on a singleand multi-bottleneck network topology. Our model accountsfor the impact of on-path caches. Protocol performance is alsoassessed via packet-level simulations and design guidelines aredrawn from previous analysis. Joint work with G. Carofiglio and L.Muscariello
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    Date:21/03/2012, 14h-onward
    Speaker:Diana Joumblatt
    Talk:Characterizing end-host application performance across multiple networking environments
    Abstract:Users today connect to the Internet everywhere - from home, work, airports, friend's homes, and more. This paper characterizes how the performance of networked applications varies across networking environments. Using data from a few dozen end-hosts, we compare the distributions of RTTs and download rates across pairs of environments. We illustrate that for most users the performance difference is statistically significant. We contrast the influence of the application mix and environmental factors on these performance differences. Joint work with Oana Goga, Renata Teixeira, Jaideep Chandrashekar and Nina Taft
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    Date:21/03/2012, 14h-onward
    Speaker:Tien Viet Nuyen
    Talk:On the Spatial Modeling of Wireless Networks byRandom Packing Models
    Abstract:In order to represent the set of transmitters simultaneouslyaccessing a wireless network using carrier sensing basedmedium access protocols, one needs tractable point processessatisfying certain exclusion rules. Such exclusion rules forbid theuse of Poisson point processes within this context. It has beenobserved that Mat¥ern point processes, which have been advocatedin the past because of their exclusion based definition, are ratherconservative within this context. The present paper confirms thatit would be more appropriate to use the point processes inducedby the Random Sequential Algorithm in order to describe suchpoint patterns. It also shows that this point process is in factas tractable as the Mat¥ern model. The generating functional ofthis point process is shown to be the solution of a differentialequation, which is the main new mathematical result of thepaper. In comparison, no equivalent result is known for theMatern hard-core model. Using this differential equation, a newheuristic method is proposed, which leads to simple bounds andestimates for several important network performance metrics.These bounds and estimates are evaluated by Monte Carlosimulation. Joint work with Francois Baccelli
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    Date:20/03/2012, 14h - 15h
    Speaker:Mark Crovella (Boston University)
    Talk:A Fine-Grained Distance Metric for Analyzing Internet Topology
    Abstract:One of the defining properties of small worlds is the prevalence of short paths connecting node pairs. Unfortunately, as a result the usual notion of distance is not particularly helpful in distinguishing neighborhoods in such graphs. This is the case, for example, when analyzing the interdomain routing system of the Internet. We describe a motivating problem that requires a finer-grained notion of distance. The problem is quite simple to state: how can any given network operator in the Internet determine which paths pass through its network. Surprisingly, the nature of Internet routing makes this question rather hard to answer. To address this problem, we define a new distance metric on graph nodes. This metric has useful and interesting properties: it is easy to compute and understand, it can be used to sharply distinguish neighborhoods in networks, and it remains useful even in small-world networks. We show how we use this metric to address our motivating problem, and more generally how it can be used for visualization and dimensionality reduction of complex networks.
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    Date:14/03/2012, 14h - 15h
    Speaker:Dohy Hong
    Talk:D-iteration method or how to improve Gauss-Seidel method
    Abstract:The aim of this paper is to present the recently proposed fluid diffusion based algorithm in the general context of the matrix inversion problem associated to the Gauss-Seidel method. We explain the simple intuitions that are behind this diffusion method and how it can outperform existing methods.Then we present some theoretical problems that are associated to this representation as open research problems. We also illustrate some connected problems such as the graph transformation and the PageRank problem.
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    Date:07/03/2012, 2pm-3pm
    Room:LINCS, Salle du conseil
    Speaker:Jordan Auge
    Talk:Measurement-Based Admission Control for Flow-Aware Implicit Service Differentiation
    Abstract:Abstract : It has previously been shown that the combined use of fair queuing and admission control would allow the Internet to provide satisfactory quality of service for both streaming and elastic flows without explicitly identifying traffic classes. In this paper we discuss the design of the required measurement based admission control (MBAC) scheme. The context is different to that of previous work on MBAC in that there is no prior knowledge of flow characteristics and there is a twofold objective: to maintain adequate throughput for elastic flows and to ensure low packet latency for any flow whose peak rate is less than a given threshold. In this talk, we consider the second objective assuming realistically that most elastic and streaming flows are rate limited. We introduce a MBAC algorithm and evaluate its performance by simulation under different stationary traffic mixes and in a flash crowd scenario. The algorithm is shown to offer a satisfactory compromise between flow performance and link utilization. Joint work with Sara Oueslati, James Roberts,23rd International Teletraffic Congress (ITC 2011), San Francisco (CA), Sep 6-8, 2011
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    Date:29/02/2012, 2pm-4pm
    Room:LINCS, Salle du conseil
    Speaker:Lucas DiCioccio, Oana Goga, Ahlem Reggani, Claudio Testa
    Talk:PAM Preview talks
    Abstract:Preview of talks at PAM 2012 and associated workshop. See individual talks for abstracts and details.
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    Date:29/02/2012, 2pm-4pm
    Room:LINCS, Salle du conseil
    Speaker:Ahlem Reggani
    Talk:An End-Host View on Local Traffic at Home and Work
    Abstract:Our work compares local and wide-area traffic from end-hosts connected to different home and work networks. We base our analysis on network and application traces collected from 47 end-hosts for at least one week. We compare traffic patterns in terms of number of connections, bytes, duration, and applications. Not surprisingly, wide-area traffic dominates local traffic for most users. Local connections are often shorter and smaller than Internet connections. Moreover, we find that name services (DNS) and network file systems are the most common local applications, whereas web surfing and P2P, which are the most popular applications in the wide-area, are not significant locally. Joint work with Fabian Schneider (NEC Laboratories Europe, Heidelberg, Germany), Renata Teixeira (UPMC Sorbonne Universite and CNRS, LIP6, Paris, France)
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    Date:29/02/2012, 2pm-4pm
    Room:LINCS, Salle du conseil
    Speaker:Claudio Testa
    Talk:Experimental Assessment of BitTorrent Completion Time in Heterogeneous TCP/uTP swarms
    Abstract:BitTorrent, one of the most widespread used P2P application for file-sharing, recently got rid of TCP by introducing an application-level congestion control protocol named uTP. The aim of this new protocol is to efficiently use the available link capacity, while minimizing its interference with the rest of user traffic (e.g., Web, VoIP and gaming) sharing the same access bottleneck. In this paper we perform an experimental study of the impact of uTP on the torrent completion time, the metric that better captures the user experience. We run BitTorrent applications in a flash crowd scenario over a dedicated cluster platform, under both homogeneous and heterogeneous swarm population. Experiments show that an all-uTP swarms have shorter torrent download time with respect to all-TCP swarms. Interestingly, at the same time, we observe that even shorter completion times can be achieved under mixtures of TCP and uTP traffic, as in the default BitTorrent settings. Joint work with D. Rossi (Telecom ParisTech), A. Rao (INRIA) and A. Legout (INRIA)
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    Date:29/02/2012, 2pm-4pm
    Room:LINCS, Salle du conseil
    Speaker:Oana Goga
    Talk:Speed Measurements of Residential Internet Access
    Abstract:The spread of residential broadband Internet access is raising the question of how to measure Internet speed. We argue that available bandwidth is a key metric of access link speed. Unfortunately, the performance of available bandwidth estimation tools has rarely been tested from hosts connected to residential networks. This paper compares the accuracy and overhead of state-of-the-art available bandwidth estimation tools from hosts connected to commercial ADSL and cable networks. Our results show that, when using default settings, some tools underestimate the available bandwidth by more than 60%. We demonstrate using controlled testbeds that this happens because current home gateways have a limited packet forwarding rate. Joint work with Renata Teixeira (UPMC Sorbonne Universite and CNRS, LIP6, Paris, France)
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    Date:29/02/2012, 2pm-4pm
    Room:LINCS, Salle du conseil
    Speaker:Lucas DiCioccio
    Talk:Probe and Pray: Using UPnP for Home Network Measurements
    Abstract:Network measurement practitioners increasingly focus their interest on understanding and debugging home networks. The Universal Plug and Play (UPnP) technology holds promise as a highly efficient way to collect and leverage measurement data and configuration settings available from UPnP-enabled devices found in home networks. Unfortunately, UPnP proves less available and reliable than one would hope. In this paper, we explore the usability of UPnP as a means to measure and characterize home networks. We use data from 120,000 homes, collected with the HomeNet Profiler and Netalyzr troubleshooting suites. Our re- sults show that in the majority of homes we could not collect any UPnP data at all, and when we could, the results were frequently inaccurate or simply wrong. Whenever UPnP-supplied data proved accurate, however, we demonstrate that UPnP provides an array of useful measurement techniques for inferring home network traffic and losses, for identifying home gateway models with configuration or implementation issues, and for obtaining ground truth on access link capacity.Joint work with Renata Teixeira (UPMC Sorbonne Universites and CNRS), Martin May (Technicolor), and Christian Kreibich (ICSI)
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    Date:22/02/2012, 2pm-3pm
    Room:LINCS, Salle du conseil
    Speaker:Calvin Chun Shue Chen (Alcatel Lucent)
    Talk:Self-Optimization of Radio Resources in Small and Macro Cell Networks
    Abstract:We propose and analyze a class of distributed algorithms performing the joint optimization of radio resources in heterogeneous cellular networks made of a juxtaposition of macro and small cells. We see that within this context, it is essential to use algorithms able to simultaneously solve the problems of channel selection, user association and power control. In such networks, the unpredictability of the cell and user patterns also requires self-optimized schemes. The proposed solution is inspired from statistical physics and is based on Gibbs sampler. It can be implemented in a distributed way and nevertheless achieves minimal system-wide potential delay. Simulation results have shown its effectiveness.
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    Date:15/02/2012, 2pm-3pm
    Room:LINCS, Salle du conseil
    Speaker:Jim Kurose (University of Massachusetts, Ahmerst)
    Talk:Design and Analysis of Content Caching Networks
    Abstract:Today's Internet architecture, nearly 40 years old now, is grounded in a model of host-to-host communication. More recently, a number of researchers have begun to focus on Content Networking - a model in which host-to-content (rather than host-to-host) interaction is the norm. Here, content distribution and retrieval, rather than host-to-host packet delivery, is the core function supported in each and every network node. A central component of proposals for such content delivery is the routing of content to requestors through a large-scale interconnected network of caches.In this talk we focus on this cache network. We begin with a quick overview of Content Networking. We then describe Breadcrumbs - a simple content caching, location, and routing system that uses a small amount of information regarding cache history/routing in a simple, best-effort approach towards caching. In the second part of this talk we consider the broad challenge of analyzing networks of interconnected caches.We describe an iterative fixed-point algorithm for approximating cache network performance, evaluate the accuracy of the approximation, and identify the sources of approximation error. We also consider the steady state behavior of cache networks. We demonstrate that certain cache networks are non-ergodic in that their steady-state characterization depends on the initial state of the system. We describe sufficient conditions (based on topology, admission control, and cache replacement policy) for ergodicity and ergodicity equivalence classes among policies. Last, we describe current work on developing a network calculus for cache network flows. Joint work with Elisha Rosensweig, Daniel Menasche, Don Towsley
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    Date:09/02/2012, 2pm-3pm
    Room:Amphi Saphir
    Speaker:Bogdan Cautis (Telecom ParisTech)
    Talk:Top-k Search in Social Tagging Systems
    Abstract:In this talk, I will present our recent work on top-k search in social tagging systems, also known as folksonomies (popular examples include Del.icio.us, StumbleUpon or Flickr). The general setting is the following: - Users form a weighted social network, which may reflect friendship, similarity, trust, etc. - Items from a public pool of items (e.g., URLs, blogs, photos, documents) are tagged by users with keywords, driven by various motivations (description, classification, to facilitate later retrieval, sociality). - Users search for items having certain tags.Going beyond the classic search paradigm where data is decoupled from the users querying it, users can now act both as producers and seekers of information. Therefore, finding the most relevant items in response to a query should be done in a network-aware manner:items tagged by users who are closer (more similar) to the seeker should be given more weight than items tagged by distant users. We propose an algorithm that has the potential to scale to current applications. We describe how a key aspect of the problem,which is accessing the closest or most relevant users for a given seeker, can be done on-the-fly (without any pre-computations) for several possible choices - arguably the most natural ones - of proximity computation in a social network. Based on this, our top-k algorithmis sound and complete, and is instance optimal in the case when the search relies exclusively on the social weight of tagging actions. To further improve response time, we then consider approximate techniques. Extensive experiments on real-world data show that these canbring significant benefit, without sacrificing precision. New issues and directions for future research will also be discussed if time allows.
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    Date:08/02/2012, 2pm-3pm
    Room:LINCS, Salle du conseil
    Speaker:Miguel Elias Mitre Campista (Universidade Federal do Rio de Janeiro, UFRJ)
    Talk:VNEXT: Virtual NEtwork management for Xen-based Testbeds
    Abstract:Network testbeds strongly rely on virtualization thatallows the simultaneous execution of multiple protocol stacks butalso increases the management and control tasks. This talkpresents a system to control and manage virtual networks basedon the Xen platform. The goal of the proposed system is toassist network administrators to perform decision making in thischallenging virtualized environment. The system managementand control tasks consist of defining virtual networks, turningon, turning off, migrating virtual routers, and monitoring thevirtual networks within few mouse clicks thanks to a user-friendlygraphical interface. The administrator can also perform high-leveldecisions, such as redefining the virtual network topologyby using the plane-separation and loss-free live migration functionality,or saving energy by shutting down physical routers. Performancetests assure the system has low response time.
    Biography:Miguel Elias Mitre Campista was born in Rio de Janeiro, Brazil, on May 8th, 1980. He received the Telecommunications Engineer degree from the Fluminense Federal University (UFF), Rio de Janeiro, Brazil, in 2003 and the M.Sc. and D.Sc. degrees in Electrical Engineering from the Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil, in 2005 and 2008, respectively. Currently, Miguel is with GTA Laboratory in COPPE/UFRJ.His major research interests are in multihop wireless networks, quality of service, wireless routing, wireless mesh networks, and home networks.
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    Date:01/02/2012, 2pm-3pm
    Room:LINCS, Salle du conseil
    Speaker:Giovanna Carofiglio (Alcatel Lucent)
    Talk:Modeling Data Transfer in Content-Centric Networks
    Abstract:The move towards a future Internet is today hindered by the mismatch between the host-oriented model, at thefoundation of the current network architecture, and the dominant content-oriented usage, centered on data disseminationand retrieval. Content-centric networking (CCN) brings a paradigm shift in the present Internet communication model byaddressing named-data instead of host locations.Important features of such networks are the availability of built-in network storage and of receiver-driven chunk leveltransport, whose interaction significantly impacts overall system and user performance.In the talk, I will focus on the performance evaluation of CCN networks and present an analytical model of bandwidthand storage sharing under fairly general assumption on total demand, topology, content popularity and limited network resources.Further, an overview of the ongoing activities and the main research challenges in this area will be provided.
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    Date:26/01/2012, 14h - 15h
    Room:Amphi Saphir
    Speaker:Laurent Georges (INRIA Roquencourt)
    Talk:Robustesse temporelle dans les systËmes embarquÈs mono et multiprocesseur
    Abstract:Le respect de contraintes temporelles strictes dans un syst√ãme temps r√àel peut √çtre garanti par l'√àtablissement de conditions de faisabilit√à "pires cas". Ces conditions de faisabilit√à sont √àtablies pour un syst√ãme temps r√àel sp√àcifi√à par diff√àrents mod√ãles (mod√ãle de taches ex√àcut√àes, mod√ãle d'ordonnancement, mod√ãle d'architecture,...). Nous nous int√àressons dans cette pr√àsentation au mod√ãle sporadique et aux ordonnancements pr√àemptifs ‚Ä° priorit√às fixes et dynamiques (Earliest Deadline First) pour des architectures mono et multiprocesseur. Le mod√ãle sporadique est d√àfini par ses hypoth√ãses "pires cas" (pire dur√àe d'execution, inter-arriv√àe minimale et √àch√àance minimale de terminaison au plus tard associ√àes aux t‚Ä
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    Date:25/01/2012, 2pm-3pm
    Room:LINCS, Salle du conseil
    Speaker:M. Jonkheere
    Talk:The Fleming Viot process driven by subcritical branching: a selection principle.
    Abstract:We consider Fleming Viot processes having the following dynamics: N particles move independently according to the dynamics of a subcritical branching process until they hit 0, at which point, they instantaneously and uniformly choose the position of one of the other particles. We first establish a coupling between the FV processes (associated to any one-dimensional dynamics) and multitype branching processes. This allows us to prove convergence of scaled version of the FV processes and ergodicity for fixed N. Using large deviations estimate for subcritical branching processes, this coupling further allows to obtain useful drift inequalities for the maximum of the Fleming Viot process. These inequalities imply in turn tightness of the family of empirical measures under measure of the branching process when N tends to infinity. the stationary measure of the FV process. Finally, we prove a selection principle: the empirical measures converge to the extremal quasi-stationary measure of the branching process when N tends to infinity.
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    Date:18/01/2012, 2pm-3pm
    Room:LINCS, Salle du conseil
    Speaker:Kim Son NGUYEN (Internship ALU/LINCS)
    Talk:PageRank extension and a new way to measure scientific impact
    Abstract:As the number of scientists and scientific publications are increasing fast, an eliminatory preliminary phase is often necessary to filter out the possible candidates for a scientific position or a scientific prize. A good method to measure the achievement and the impact of an author/a publication is therefore needed. In the talk, we will develop a PageRank-like measure in the scientific world by discussing about the possible extensions and necessary constraints in order to keep the method the most reliable possible.
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    Date:15/12/2011, 14h - 15h
    Room:Amphi Saphir
    Speaker:Aldric Degorre (LIAFA)
    Talk:Volume and Entropy of Timed Regular Languages
    Abstract:For timed languages, we define size measures: volume for languages with afixed finite number of events, and entropy (growth rate) as asymptotic measurefor an unbounded number of events. These measures can be used for quantitativecomparison of languages, and the entropy can be viewed as information contentsof a timed language.In the case of languages accepted by deterministic timed automata, we giveexact formulas for computing volumes, of which we deduce a characterization ofentropy and propose several methods to compute it.One method involves functional analysis: we characterize the entropy as thelogarithm of the spectral radius of the positive integral operator whichtransforms volume functions and use this characterization.Another method involves discretizing the automaton and approximating itsentropy by the entropy of a finite automaton.Finally we show, in the case of automata with punctual guards, how defects ofdimension in the polyhedra of possible timings can be dealt with.
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    Date:07/12/2011, 14h - 15h
    Room:LINCS 23 av Italie
    Speaker:Fabien Mathieu (INRIA/ENS)
    Talk:Performance of P2P Networks with Spatial Interactions of Peers
    Abstract:We propose a new model for peer-to-peer networking which takes thenetwork bottlenecks into account beyond the access. This model allowsone to cope with the fact that distant peers often have a smaller ratethan nearby peers. We show that the spatial point process describingpeers in their steady state exhibits an interesting repulsionphenomenon. We study the implications of this phenomenon by analyzingtwo asymptotic regimes of the peer-to-peer network: the fluid regimeand the hard--core regime. We get closed form expressions for the mean(and in some cases the law) of the peer latency and the download rateobtained by a peer as well as for the spatial density of peers in thesteady state of each regime. The analytical results are based on a mixof mathematical analysis and dimensional analysis and have importantdesign implications.This is a joint work with Franois Baccelli and Ilkka Norros
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    Date:30/11/2011, 14h - 15h
    Room:LINCS, 23 av Italie, Salle de Conseil
    Speaker:Konstantinos Katsaros (Athens University of Economics and Business)
    Talk:Future Internet: An information-centric perspective
    Abstract:Although the Internet has been designed as a network for the pairwisecommunication between end hosts, the current traffic-mix reveals thatit is currently used for the massive distribution of information.Based on a host-centric architecture, the Internet serves as acommunication infrastructure interconnecting requests to theinformation itself. In view of this model mismatch, the networkingcommunity has started to investigate architectures for a FutureInternet many of which revolve around information-centrism. In thistalk, we will provide an overview of the emerging Information-CentricNetworking (ICN) paradigm, highlighting its main features anddiscussing the ways it offers a promising alternative to the currentInternet architecture. We will take a close look at the current ICNresearch efforts, including our work in the field, and point out theircommonalities and key differences. Finally, we will identify keyresearch challenges in the area, fostering further discussion on the topic.
    Biography:Konstantinos Katsaros received his B.Sc., M.Sc. and Ph.D. degrees in2003, 2005 and 2010 respectively from the Department of Computer Science,Athens University of Economics and Business, Greece. His PhD thesis was oncontent distribution and mobility support in the context of theInformation-Centric Networking (ICN) paradigm. His current research isalso in the area of ICN, focusing on scalable information discovery andname resolution, policy compliant routing, packet-level caching andmultipath routing. He has also worked in the areas of multicast andbroadcast service provision over next generation cellular networks, mobilegrid computing and cognitive radio.
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    Date:16/11/2011, 14h - 15h
    Room:LINCS, 23 av Italie, Salle de Conseil
    Speaker:Francois Durand (Alcatel Lucent Bell Labs/INRIA)
    Talk:Manipulability of Voting Systems
    Abstract:Voting systems allow competing entities to decide among different options. In order to ensure fairness between the competing entities, a strong requirement is to avoid manipulability by voters. Unfortunately, strong theoretical results show that, unless using some "degenerated" and a priori non-acceptable voting systems such as the dictatorial ones, any other voting system is susceptible to be manipulated by a single voter! However, very little is know about how much a voting system is manipulable. We evaluate different voting systems by quantifying their probability of manipulability on various kinds of voter populations. The results are very general and can be applied in any context where voting systems can be used.
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    Date:02/11/2011, 14h00
    Room:LINCS, 23 av Italie, Salle de Conseil
    Speaker:Antonio Kung (Trialog, CTO)
    Talk:Practicing Interoperability: Technical and Scientific Challenge
    Abstract:A technical and scientific understanding of interoperability has been available for years in the telecom industry. But the practice of interoperability needs to evolve because of the speed with which ICT ecosystems are created. This talk will present the reasons why this is the case and subsequently call for further technical and scientific research. The presentation will include the following points.
    • Practice of interoperability today
      • Research (e.g. DIEM and ARTEMIS projects)
      • Business practices (Handling IPR, Standardisation)
    • Practice of interoperability in the future
      • ICT ecosystems needs
      • Societal aspects (legal, business, ethical)
      • Technical aspects (platform viewpoint, deployment viewpoint)
      • Engineering aspects (interoperability by design, interoperability assurance)
      • Business practices and consensus building (Harvard roadmap)
    • Discussion
    Biography:Antonio Kung has 30-year experience in embedded systems. He was initially involved in the development of real-time kernels, before co-founding Trialog in 1987, where he now serves as CTO. He heads the company product development (kernels, protocols, tools) as well as collaborative projects with a focus on embedded systems, security privacy trust and ICT for ageing. He is involved in the promotion of initiatives towards common platforms and interoperability. He holds a Master's degree from Harvard University and an Engineering degree from Ecole Centrale Paris.
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    Date:21/10/2011, 10h30
    Room:LINCS, 23 av Italie, Salle de Conseil
    Speaker:Micheal Ment (Univ. of Tbingen)
    Talk:Resilient Networking and Resource Management in IP Networks
    Abstract:Resilience analysis in packet-based communication networks quantifies the risk of link overload dueto rerouted traffic and the risk of disconnectivity. Proactive optimization of routing and reroutingmay reduce the first risk, improvement of the network topology the second one. Recently, IP fastreroute mechanisms have been suggested by the IETF. Loop-free alternates (LFAs) are simple, butthey may not cover all single element failures.The IETF has recently defined Pre-Congestion Notification (PCN) for Differentiated Services networks.It uses simple load-dependent packet re-marking to communicate load conditions to edge. Thisinformation is used for admission control and flow termination. The latter is useful to removeoverload that occurs in spite of admission control due unexpected events. However, termination canbe avoided if admissible rate thresholds are set low enough, which is the principle of resilientadmission control.Today's access networks suffer from a minority of heavy users who are responsible for most trafficand compromise the quality of experience for a majority of light users. Some ISPs rate-limit the useraccess, others use deep packet inspection to classify and downgrade some traffic which violatesnetwork neutrality. To tackle that problem, the IETF defines Congestion Exposure (ConEx). It makescongestion visible to any IP device along a flow's path. This information may be used to throttle theuser access to achieve per-user fairness rather than per-flow fairness, to improve traffic engineering,and to enhance SLAs.
    Biography:Michael Menth is a full professor at the Department of Computer Science at the University ofTuebingen/Germany and head of the Communication Networks chair. He received a Diploma andPhD degree in 1998 and 2004 from the University of Wuerzburg/Germany.Prior he was studyingcomputer science at the University of Texas at Austin and worked at the University of Ulm/Germany.His special interests are performance analysis and optimization of communication networks,resource management, resilience issues, and Future Internet. He holds numerous patents andreceived various scientific awards for innovative work.
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    Date:19/10/2011, 14h - 15h
    Room:LINCS, 23 av Italie, Salle de Conseil
    Speaker:Dave Taht
    Abstract:Bufferbloat - Identification, analysis, tools for analyzing overly deep buffering across the (mostly wireless) internet, with some potential for solutions. For an introduction to the bufferbloat problem, see Jim Gettys'talk http://gettys.wordpress.com/2011/06/02/google-techtalk-video-is-up/This talks reportes latest update of work in progress, more information is available online at http://lwn.net/Articles/458625/ or http://www.bufferbloat.net/
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    Date:29/09/2011, 14h - 15h
    Room:LINCS, 23 av Italie, Salle de Conseil
    Speaker:Catherine Rosenberg (University of Waterloo)
    Talk:How can the Internet help smarten the grid
    Abstract:This seminar presents the research activities on Smart Grids of the Information Systems and Sciences for Energy (ISS4E) laboratory co-founded by Professors Rosenberg and Keshav at University of Waterloo. After a brief introduction on smart grids and their similarities with the Internet, two research projects will be presented. The first is on dimensioning transformers and storage using probabilistic analysis. The second one, on demand response, proposes a solution to take advantage of the elasticity inherent to most of the major home appliances. All these projects are conducted in collaboration with Prof. Keshav and graduate students.
    Biography:Catherine Rosenberg is a Professor in Electrical and Computer Engineering at the University of Waterloo. Since June 2010, she holds the Canada Research Chair in the Future Internet. She started her career in ALCATEL, France and then at AT&T Bell Labs., USA. From 1988-1996, she was a faculty member at the Department of Electrical and Computer Engineering, Ecole Polytechnique, Montral, Canada. In 1996, she joined Nortel Networks in the UK where she created and headed the R&D Department in Broadband Satellite Networking. In August 1999, Dr. Rosenberg became a Professor in the School of Electrical and Computer Engineering at Purdue University where she co-founded in May 2002 the Center for Wireless Systems and Applications (CWSA). She joined University of Waterloo on Sept 1st, 2004 as the Chair of the Department of Electrical and Computer Engineering for a three-year term.Catherine Rosenberg is on the Scientific Advisory Board of France-Telecom and is a Fellow of the IEEE.
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    Date:05/08/2011, 10am-11am
    Room:LINCS, 23 av Italie, Salle de Conseil (#24)
    Speaker:S. Felix Wu, UC Davis
    Talk:On Leveraging Social Informatics for Cyber Security
    Abstract:A fundamental challenge of trustworthy computing is to develop a systematic and yet practical/usable approach on determining whether or not, and how much a piece of information (e.g., software program or information content) should be trusted. The focus of this talk is our trust management architecture, called DSL (Davis Social Links) based on social informatics, i.e., information about human social relationships and the interactions based on those relationships. Under the DSL architecture, we will discuss how to enhance the trustworthiness of distributed applications running on top of todayu2019s Internet, and furthermore, how to re-design a brand new trustworthy Internet architecture based on social informatics. The speaker will perform some small demos during his talk.
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    Date:30/06/2011, 3pm-4pm
    Room:LINCS, Salle du conseil
    Speaker:M. Gagnaire, joint work with E. Doumith and S. Al Zahr
    Talk:Mutual Impact of Traffic Correlation and Regenerator Concentration in Translucent WDM Networks
    Abstract:Since the early 2000s, a real attention is paid tophysical impairments arising in large-scale optical networks. Onecost-effective solution to cope with transmission impairments is todeploy 3R (re-amplifying, re-shaping, and re-timing) regeneratorsin a limited number of network nodes (i.e., translucent networks).Taking into account the simultaneous effect of four transmissionimpairments (amplified spontaneous emission, chromatic dispersion,polarization mode dispersion, and nonlinear phase shift), wepropose a novel exact approach for impairment-aware networkplanning. In contrast with previous works, we investigate theproblem under pre-planed dynamic traffic. Our proposal takesadvantage of the dynamics of the traffic pattern so that regenerationresources may be shared among non-concurrent requests.Given a network topology and a set of pre-planned requests, wetarget the minimum number of regenerators or/and regenerationsites. Thanks to an ILP formulation of this problem, we outline throughthe obtained numerical results the mutual impact between thetime-correlation of the requests and the level of regenerators' concentration.
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    Date:30/06/2011, 2pm-3pm
    Room:LINCS, Salle du conseil
    Speaker:M. Zukerman
    Talk:Modeling and blocking probability evaluation for multi-priority circuit switched optical networks
    Abstract:It is expected that circuit switching (CS) will play an importantmajor role in future optical networks. CS normally does not requirebuffering which is very costly in the optical domain. If the trafficon a CS network is well managed CS networks can guarantee quality ofservice (QoS) to customers in a way that can even lead to efficientlink utilization and low consumption of energy per bit. In the coreInternet, where traffic is heavily multiplexed, it is easier toachieve high utilization and therefore the role of CS at the core isclearly important. However, CS can also lead to a green and efficientoperation end-to-end for large bursts of data. Accurate, robust andscalable blocking probability evaluation is an important element in CStraffic management. We consider an optical network that uses variouscircuit-switching based technologies such as OCS and OFS. We model itas two-priority circuit-switched network with non-hierarchicalalternate routing. We evaluate the blocking probability usingalgorithms based on the Erlang Fixed-point Approximation (EFPA) andthe Overflow Priority Classification Approximation (OPCA). For aparticular example of a 6-node fully meshed network with alternaterouting, we compare numerically between OPCA over EFPA and discusstraffic implications.
    Biography:Moshe Zukerman received his B.Sc. in Industrial Engineeringand Management and his M.Sc. in Operation Research fromTechnion-Israel Institute of Technology and a Ph.D. degree inEngineering from The University of California Los Angeles in 1985.During 1986-1997 he served in Telstra Research Laboratories (TRL).During 1997-2008 he was with The University of Melbourne. In Dec 2008,he joined City University of Hong Kong where he is a Chair Professorof Information Engineering. He has served on the editorial boards ofvarious journals such as IEEE JSAC, IEEE/ACM Transactions onNetworking, IEEE Communications Magazine, Computer Networks andComputer Communications. Prof. Zukerman has over 300 publications inscientific journals and conference proceedings, has been awardedseveral national and international patents, two conference best paperawards and honorary Professorships at CCNU, Wuhan; CityU, Hong Kong;and BJTU, Beijing. He is a Fellow of the IEEE and has served as amember and Chair of the IEEE Koji Kobayashi Computers andCommunications Award Committee.
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    Date:23/06/2011, Jeudi 23 juin 2011
    Room:amphi Saphir
    Speaker:Venkat Anantharam (UC Berkeley)
    Talk:Anonymity over Networks
    Abstract:Mixes are relay nodes that accept packets arriving from multiple sourcesand release them after variable delays to prevent an eavesdropper fromassociating outgoing packets to their sources. We assume that each mixhas a hard latency constraint. Using an entropy-based measure toquantify anonymity, we analyze the anonymity provided by networks ofsuch latency-constrained mixes. Our results are of most interest underlight traffic conditions. A general upper bound is presented that boundsthe anonymity of a single-destination mix network in terms of a linearcombination of the anonymity of two-stage networks. By using a specificmixing strategy, a lower bound is provided on the light trafficderivative of the anonymity of single-destination mix networks. Thelight traffic derivative of the upper bound coincides with the lowerbound for the case of mix-cascades (linear single-destination mixnetworks). *Sance coorganise avec Aslan Tchamkerten de COMELEC.*
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     to be confirmed
    Date:15/06/2011, TBD
    Room:all day
    Talk:XVII Forum IFSTTAR, Gestion de la Relation Client & Transport
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    Date:19/05/2011, Jeudi 19 mai 2011 14h
    Room:amphi Saphir
    Speaker:Pierre Latouche
    Talk:Modles de graphe alatoire classes chevauchantes pour l'analyse des rseaux
    Abstract:Les rseaux sont largement utiliss dans de nombreux domaines scientifiquesafin de reprsenter les intractions entre objets d'intrt. Ainsi, enbiologie, les rseaux de rgulation s'appliquent dcrire les mcanismesde rgulation des gnes, partir de facteurs de transcription, tandis queles rseaux mtaboliques permettent de reprsenter des voies de ractionsbiochimiques. En sciences sociales, ils sont couramment utiliss pourrprsenter les intractions entre individus. Dans ce contexte, denombreuses mthodes non-supervises de clustering ont t dveloppes afind'extraire des informations, partir de la topologie des rseaux. Laplupart d'entre elles partitionne les noeuds dans des classes disjointes,en fonction de leurs profils de connection. Rcemment, des tudes ont misen vidence les limites de ces techniques. En effet, elles ont montr qu'ungrand nombre de rseaux "rels" contenaient des noeuds connus pourappartenir plusieurs groupes simultanment. Pour rpondre ce problme,nous proposons l'Overlapping Stochastic Block Model (OSBM). Cette approcheautorise les noeuds appartenir plus d'une classe et gnralise le trsconnu Stochastic Block Model, sous certaines hypothses. Nous montrons quele modle est identifiable dans des classes d'quivalence et nous proposonsun algorithme d'infrence bas sur des techniques variationnelles globaleset locales. Finalement, en utilisant des donnes simules et relles, nouscomparons nos travaux avec d'autres approches.
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    Date:19/05/2011, Jeudi 19 mai 2011 15h15
    Room:amphi Saphir
    Speaker:Philippe Gambette
    Talk:Problmes d'optimisation combinatoire pour la reconstruction de rseauxphylogntiques
    Abstract:Les rseaux phylogntiques gnralisent le modle de l'arbre pourdcrire l'volution des espces, en permettant des artes entre lesbranches de l'arbre d'exprimer des changes de matriel gntiqueentre espces coexistantes. De nombreuses approches combinatoires -fondes sur la manipulation d'ensembles finis d'objets mathmatiques -ont t conues pour reconstruire ces rseaux partir de donnesextraites de plusieurs arbres de gnes contradictoires. Elles sedivisent en plusieurs catgories selon le type de donnes en entres(triplets, quadruplets, clades ou bipartitions) et les restrictions destructure sur les rseaux reconstruits.Je prsenterai plusieurs problmes d'optimisation combinatoire sur lesrseaux phylogntiques, concernant leur reconstruction partir detriplets ou de clades. Je dcrirai des mthodes de rsolution basessur des algorithmes exacts (de complexit paramtre notamment) ou desheuristiques.
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    Date:12/05/2011, Jeudi 12 mai 2011 14h
    Room:amphi Saphir
    Speaker:Anthony Leverrier
    Talk:Graphes de secrets
    Abstract:Le concept de "graphe quantique" a rcemment t introduit pourgnraliser celui de graphe alatoire. Dans ce modle, chaque liendu graphe correspond un tat quantique bipartite non maximalementcorrl et les noeuds ont la capacit d'appliquer des oprationslocales leur systme quantique ainsi que de communiquerclassiquement dans le but d'tablir des corrlations quantiquesmaximales. Ce modle conduit l'apparition de proprits inattenduesen ce qui concerne la percolation (Acn et al, Nature Physics 2007)ou l'apparition de sous-graphes donns dans un graphe de grandetaille (Perseguers et al, Nature Physics 2010).Dans cet expos, on s'intresse un nouvel objet, intermdiaire entreles graphes alatoires et les graphes quantiques : les graphes desecrets . Dans ce modle, chaque paire de noeuds reoit un bit secretidentique, mais biais. Les noeuds sont autoriss agir localementsur leurs donnes et communiquer de manire publique dans le butd'tablir de nouvelles corrlations secrtes constitues de bits nonbiaiss.On montrera que ces graphes de secrets partagent de nombreusesproprits communes avec les graphes quantiques, et donc que cesproprits ne sont pas intrinsquement d
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    Date:12/05/2011, Jeudi 12 mai 2011 15h15
    Room:amphi Saphir
    Speaker:David Auger
    Talk:Comment jouer dans l'incertain : thorie et pratique
    Abstract:Un jeu est dit observation partielle (ou information imparfaite) si lesjoueurs n'ont pas accs l'histoire entire de la partie lors des prisesde dcision. Parmi les jeux bien connus, citons titre d'exemple les jeuxde cartes - poker, tarot- ou la bataille navale, ainsi que les versionsdites fantmes de jeux classiques : go fantme, kriegspiel (checsfantmes), morpion fantme.Une problmatique fondamentale pour ces jeux est le calcul d'quilibreset de stratgies, que ce soit a priori ou de faon "online" (au coursdu jeu). Au-del du cadre des jeux proprement dit, ces questions sontpertinentes pour l'optimisation en environnement incertain et adversarial:rseaux, gestions de stocks ou de portefeuilles. La complexit inhrente ces problmes en font l'heure actuelle un des dfis majeurs del'intelligence artificielle.Nous prsenterons un tat de l'art et en particulier des algorithmesstochastiques de minimisation de regret - mthodes dites de banditsmanchots et algorithmes de Monte Carlo Tree Search - ainsi qu'une mthodeque nous avons dveloppe pour les adapter au cadre de l'observationpartielle.
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    Date:05/05/2011, Jeudi 5 mai 2011 14h
    Room:amphi Saphir
    Speaker:Alain Couvreur
    Abstract:Introduits par Gallager dans les annes 60, puis redcouverts durant lesannes 90, les codes LDPC (Low-Density Parity-Check), font l'heureactuelle partie des codes les plus utiliss en pratique. Pour les produire,on distingue deux approches. La premire consiste gnrer la matrice deparit du code alatoirement et la seconde utiliser des matrices creusesissues d'objets combinatoires (designs, structures d'incidence).Dans cet expos, je prsenterai des structures d'incidence nouvellesobtenues partir de relations d'incidence entre drapeaux (la donne d'unpoint et d'une droite le contenant) et coniques du plan affine.On s'intresse ensuite aux codes LDPC provenant de ces structuresd'incidence, dont certaines caractristiques (distance minimale, maille dugraphe de Tanner, nombre de cycles minimaux) peuvent tre dtermines pardes mthodes gomtriques. On terminera par la prsentation de simulationsdes performances de ces codes sur le canal Gaussien.
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    Date:05/05/2011, Jeudi 5 mai 2011 15h15
    Room:amphi Saphir
    Speaker:Bertrand Meyer
    Talk:Constructions et bornes pour les codes tmoin
    Abstract:tant donn un code binaire C, on appelle tmoin d'un mot de code c parrapport C tout ensemble d'indices W tels que la restriction du mot c W distingue c de tout autre mot de code. On peut se demander quel estle cardinal maximal d'un code de longueur donne tel que chaque motpossde un tmoin de longeur fixe. Cette question est ouverte. Nousprsenterons des constructions de codes avec un grand cardinal et nousmontrerons dans certains cas que leur taille est optimale. Nousutiliserons pour cela le nombre theta de Lovasz pour les graphes et unetechnique d'optimisation inspire de la mthode de la programmationlinaire de Delsarte combine des arguments de rduction par legroupe de symtrie.
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    Date:28/04/2011, Jeudi 28 avril 2011 15h15
    Room:amphi Saphir
    Speaker:Eleonora Guerrini
    Talk:Des idaux de polynmes pour les codes systmatiques
    Abstract:Dans cet expos un modle algbrique pour la caractrisation des codescorrecteurs systmatiques est prsente. L'intrt pour cette familledrive de la volont de gnraliser les codes linaires afin derechercher des codes qui soient optimaux du point de vue de ladistance. En fait, il est possible dmontrer que tout code linaireest quivalent un code systmatique, mais il existe des codessystmatiques non-linaires distance plus grande de tout linairequi partage les m
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    Date:28/04/2011, Jeudi 28 avril 2011 14h
    Room:amphi Saphir
    Speaker:Sorina Ionica
    Talk:Couplages et volcans d'isognies
    Abstract:Les volcans d'isognies sont des graphes dont les noeuds sont des courbeselliptiques et les artes sont des l-isognies entre les courbes.Ces structures, introduites par Kohel dans le but de calculer l'anneaud'endomorphismes d'une courbe, ont plusieurs applications en cryptographie:dans les algorithmes de comptage des points, dans la constructions decertaines fonctions de hachage etc.Des algorithmes pour le parcours de ces graphes ont t proposs par Kohel(1996) et Fouquet et Morain (2001). Cependant, jusqu' prsent, il n'taitpas possible de prdire la direction d'un pas sur le volcan; de fait,un grand nombre de pas successifs tait ncessaire avant de dterminer ladirection prise.Je prsenterai une mthode qui permet de s'orienter dans ces graphes,lorsque la cardinalit des courbes elliptiques est connue. Cette mthode,base sur le calcul du couplage de Tate, est trs efficace et donne, dansbeaucoup de cas, des algorithmes plus rapides que les mthodes existantespour le parcours des volcans d'isognies.
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    Date:21/04/2011, Jeudi 21 avril 2011 15h15
    Room:amphi Saphir
    Speaker:Brice Mayag
    Talk:MACBETH 2-additif: une nouvelle mthode interactive d'aide la dcision
    Abstract:L'Aide MultiCritre la Dcision (AMCD) a pour but de dterminer parmiun ensemble d'alternatives ou options celle qui est la meilleure, sur basede plusieurs critres souvent contradictoires. Ce processus dbute par unrecueil d'information prfrentielle auprs du dcideur. En fonction de lanature du problme rsoudre, un modle d'aide la dcision est construit partir de cette information prfrentielle.Nous prsentons un nouveau modle de reprsentation des prfrences de typeordinale ou cardinale (incluant des intensits de prfrences du dcideur),modle qui prsente l'avantage de prendre en compte les interactionspouvant exister entre les critres de dcision. Notre approche est basesur l'utilisation de l'intgrale de Choquet 2-additive comme fonctiond'agrgation et sur une gestion des incohrences travers des techniquesde programmation linaire. La mthode obtenue est une gnralisation del'approche interactive MACBETH, d'o son nom MACBETH 2-additif.
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    Date:21/04/2011, Jeudi 21 avril 2011 14h
    Room:amphi Saphir
    Speaker:David Duris
    Talk:Acyclicit des hypergraphes et applications
    Abstract:Il existe plusieurs faons non quivalentes de gnraliser l'acyclicitdes graphes aux hypergraphes. Nous allons prsenter les quatre notionsles plus rpandues : la Berge, gamma, beta et alpha-acyclicit. Pourcela, nous donnerons des caractrisations de natures diverses(algorithmique, en termes d'arbre de jointure ou tout simplementd'absence de certains types de cycles). Puis nous verrons comment,dans diffrents contextes (logique, mthodes de dcomposition,complexit de problmes d'optimisation), certaines de ces notions sontplus adaptes que d'autres.
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    Date:14/04/2011, Jeudi 14 avril 2011 14h
    Room:amphi Saphir
    Speaker:Makhlouf Hadji
    Talk:Optimisation des rseaux composantes unicycliques : approche polydrale
    Abstract:Mes travaux s'inscrivent dans le domaine de l'optimisation combinatoire.On utilise l'approche polydrale pour rsoudre des problmes combinatoiresqui se posent dans le contexte des rseaux de tlcommunications.On introduit et tudie le problme d'optimisation des rseaux composantesconnexes unicycliques. Aprs avoir rappel que le problme est facile rsoudre en absence d'autres contraintes, on tudie de nouvelles variantesen intgrant de nouvelles contraintes techniques.On commence par une contrainte portant sur la taille des cycles. On souhaiteinterdire tous les cycles contenant au plus p sommets. Le problme est alorsNP-Difficile. Des ingalits valides sont alors proposes pour ce problme.On montre sous des conditions bien prcises que ces ingalits peuvent tredes facettes. Plusieurs algorithmes polynmiaux ont t proposs pour lasparation des ingalits valides. Ces algorithmes sont mis en oeuvre et desrsultats numriques sont donns.On se focalise par la suite sur un nouveau problme dit de Steinerconsistant partitionner un rseau en composantes unicycliques tout enimposant que certains sommets soient sur les cycles. On montre alors que ceproblme est facile au sens de la complexit algorithmique en proposant unalgorithme polynomial et une formulation tendue du problme. D'autrescontraintes techniques sont prises en compte : contraintes de degrs,contraintes sur le nombre de composantes connexes, appartenance de certainssommets une mme composante connexe et enfin la sparation de certainssommets qui doivent tre sur des composantes diffrentes.
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    Date:14/04/2011, Jeudi 14 avril 2011 15h15
    Room:amphi Saphir
    Speaker:Christophe Mouton
    Talk:Visualisation scientifique interactive et collaborative
    Abstract:Les exploitants de systmes complexes industriels sont amens, entreautres missions, anticiper la faisabilit de nouvelles gammes defonctionnement ou faire voluer des processus en fonction de nouvellesrglementations. Pour ce faire, les mtiers de l'ingnierie et de R&Dsont interrogs et mettent en oeuvre des outils de modlisation etsimulation numrique.Grs au sein d'une dmarche projet communment adopte par l'industrie,diffrents corps de mtiers doivent participer de manire conjointe unprocessus dcisionnel avec une varit de points de vue la sourced'incomprhensions ncessaires, introduisant des mises au pointimpactant parfois significativement le dlai de ralisation des tudes.La visualisation scientifique 3D interactive est un des vecteurs lesplus efficaces de partage de l'information et pourrait apporter une aideprcieuse aux projets pour crer un rfrentiel commun entre diffrentsmtiers. Force est de constater qu'un tel outil demeure cependantcantonner au sein des bureaux d'tude du fait de son cot et de sacomplexit matrielle et logicielle faute de disposer d'un environnementpartag, ou intgr au sein mme de l'entreprise, de visualisationinteractive et collaborative.Cette prsentation abordera les enjeux de la mise en place d'une tellecommunication mdiatise autant au travers de son insertion dans desprocessus mtiers dj en place que dans ses contraintes de performancestechniques et d'utililisabilit. Une dmarche complte intgrant une rponse technologique centreutilisateurs et conue au cours du projet de Ple de ComptitivitCARRIOCAS sera prsente ainsi que des axes d'investigation moyenterme tirant partie de la convergence de rcentes avancestechnologiques Internet et de visualisation 3D.
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    Date:14/04/2011, Jeudi 14 avril 2011 16h30
    Room:amphi Saphir
    Speaker:Nizar Messai
    Talk:Analyse de Concepts Formels par Similarit : Fondements et Applications
    Abstract:L'Analyse de Concepts Formels (ACF) est une mthode de classificationconceptuelle qui s'appuie sur la thorie des treillis pour mettre envidence les structures et relations sous-jacentes des donnesbinaires. L'ACF a servi de base pour de nombreuses approches en analyseet fouille de donnes, apprentissage, aide la dcision, etc. Cesapproches sont souvent pnalises par le processus de transformationdes donnes souvent complexes (non binaires). Dans cet expos, jeprsente l'ACF par similarit (ACFS) qui s'appuie sur des connaissancesde domaine pour tendre l'ACF des donnes complexes. Les connaissancesde domaines, exprimes sous diffrentes formes, permettent de calculerla similarit entre les donnes complexes et de dduire leurs structuresconceptuelles sous-jacentes. L'aspect original de l'ACFS est lapossiblit d'obtenir, pour un mme jeu de donne, des classificationsde diffrents niveaux de granularit. Cet aspect est particulirementintressant pour l'exploration interactive et la fouille progressivedes donnes et permet, entre autres, d'effectuer des zooms avant/arrireselon le besoin en prcision ou en abstraction qu'on souhaite avoir surces donnes. La deuxime partie de cet expos sera consacre l'utilisation de l'ACFS pour l'exploration progressive des donnes dansun contexte de dcouverte de ressources biologiques, pour l'aide ladcision en agronomie, pour la composition de services Web ainsi quepour la visualisation dcisionnelle dans un contexte BusinessIntelligence.
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    Date:07/04/2011, Jeudi 7 avril 2011 14h
    Room:amphi Saphir
    Speaker:Franois Delbot
    Talk:Comparaison et valuation en moyenne d'algorithmes d'approximation pourle problme du vertex cover
    Abstract:Dans la littrature, on considre souvent qu'un algorithme d'approximationpolynomial est plus performant qu'un autre lorsqu'il possde un meilleurrapport d'approximation en pire cas. Cependant, il faut tre conscient quecette mesure, dsormais "classique", ne prend pas en compte la ralit detoutes les excutions possibles d'un algorithme (elle ne considre que lesexcutions menant la plus mauvaise solution). Dans mes travaux, je mesuis focalis sur le problme du vertex cover et j'ai tent de mieux"capturer" le comportement des ces algorithmes d'approximation en montrantque les performances moyennes d
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    Date:07/04/2011, Jeudi 7 avril 2011 15h15
    Room:amphi Saphir
    Speaker:Sonia Toubaline
    Talk:Problmatiques de scurit ou de fiabilit pour certains problmes de graphes
    Abstract:Dans une problmatique de scurit ou de fiabilit, nous considrons lesversions des k artes (sommets) les plus vitales (vitaux) et de min arte(sommet)-bloqueur pour diffrents problmes de graphes. Etant donn unproblme d'optimisation P dfini sur un graphe valu, le problme "k MostVital Edges (Nodes) P" consiste dterminer un sous-ensemble de k artes(sommets) dont la suppression du graphe dgrade au maximum la valeuroptimale de P. Le problme complmentaire, "Min Edge (Node) Blocker P",consiste supprimer un sous-ensemble d'artes (sommets) de cardinalitminimale tel que la valeur optimale de P est, selon la nature de P,infrieure ou gale ou suprieure ou gale un seuil spcifique. Noustudions la complexit, l'approximation et la rsolution exacte de cesquatre versions pour les problmes de graphes suivants : arbre couvrantde valeur minimale, affectation de valeur minimale, stable de valeurmaximale, couverture de valeur minimale, 1-mdian, 1-centre, flot decot minimal et flot maximum. Ainsi, nous proposons des preuves deNP-difficult au sens fort ou de polynomialit pour des classesparticulires de graphes, des rsultats d'approximation, des algorithmesd'numration explicite ou implicite pour rsoudre ces problmes ouencore une formulation par programmation linaire.
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    Date:31/03/2011, 14h - 15h
    Speaker:Rodney Van Meter (Keio University)
    Talk:Recursive Quantum Repeater Networks
    Abstract:Internet-scale quantum repeater networks will be heterogeneous inphysical technology, repeater functionality, and management. Theclassical control necessary to use the network will therefore facesimilar issues as Internet data transmission. Many scalability andmanagement problems that arose during the development of theInternet might have been solved in a more uniform fashion, improvingflexibility and reducing redundant engineering effort. Quantumrepeater network development is currently at the stage where we risksimilar duplication when separate systems are combined. We proposea unifying framework that can be used with all existing repeaterdesigns. We introduce the notion of a Quantum Recursive NetworkArchitecture, developed from the emerging classical concept ofRECURSIVE NETWORKS, extending recursive mechanisms from afocus on data forwarding to a more general distributed computingrequest framework. Recursion abstracts independent transit networksas single relay nodes, unifies software layering, and virtualizesthe addresses of resources to improve information hiding andresource management. Our architecture is useful for buildingarbitrary distributed states, including fundamental distributedstates such as Bell pairs and GHZ, W, and cluster states.
    Biography:Rodney VAN METER received a B.S. in engineering and applied sciencefrom the California Institute of Technology in 1986, an M.S. incomputer engineering from the University of Southern California in1991, and a Ph.D. in computer science from Keio University in 2006.His research interests include storage systems, networking, andpost-Moore's Law computer architecture. He has held positions in bothindustry and academia in the U.S. and Japan. He is now an AssociateProfessor of Environment and Information Studies at Keio University'sShonan Fujisawa Campus. Dr. Van Meter is a member of AAAS, ACM andIEEE.
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    Date:24/03/2011, Jeudi 24 mars 2011 14h
    Room:amphi Saphir
    Speaker:Anastasia Bezerianos (Centrale)
    Talk:User-centered designed visualization and analysis of graphs
    Abstract:Visual analytics suffers from the size and complexity of datathat need to be presented in an understandable manner. In this talk Iwill describe different approaches we have taken in dealing with datasize and complexity, including the design of novel visualrepresentations and the use of large collaborative displays. I willillustrate these approaches with user-centered designs for visualizingand exploring graph data, such as social networks and genealogygraphs.
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    Date:17/03/2011, Jeudi 17 mars 2011 14h
    Room:amphi Saphir
    Speaker:Pascal Moyal (Univ. Tech. Compigne)
    Talk:Limite en grand graphe pour une pidmie SIR sur un rseau alatoire
    Abstract:Nous considrons une pidmie SIR se propageant sur un graphe, dontla distribution des degrs est fixe, et o les artes sont rparties alatoirement, sur le principe du modle de configuration. L'volutionde l'pidmie est totalement dcrite par une quation diffrentiellestochastique mettant en jeu trois mesures ponctuelles. Nous proposonsune limite de ce modle en grand graphe, et donnons en corollaire,une preuve rigoureuse des quations pidmiologiques obtenuespar Volz (2008).
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    Date:10/03/2011, 14h
    Room:Amphi Rubis
    Speaker:Alexis Polti et Samuel Tardieu
    Talk:Experience de pedagogie active en cycle master
    Abstract:Apres un bref rappel des principes et specificites de la pedagogie active, la presentation sera illustree par leurenseignement de cycle master : mise en oeuvre, reussites et difficultes, retour des etudiants.
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    Date:04/03/2011, 10h
    Room:DA006 Dareau (organized by TSI)
    Speaker:Dah Ming Chiu (Chinese University of Hong Kong, CUHK)
    Talk:Models and replication algorithms for P2P-assisted VoD
    Abstract:We consider a P2P-assisted Video-on-Demand system whereeach peer can store a relatively small number of moviesto offload the server when these movies are requested.How much local storage is needed -- How does this depend onthe other system parameters, such as number of peers,number of movies, the relative uploading capacity frompeers relative to playback rate, and the skewness inmovie popularity -- How many copies should the system keepfor each movie, and how does it depend on movie popularity --Should all movies be replicated in the P2P system, orshould some be kept at the server only -- If the latter,which movies should be kept at the server -- Once we havean understanding of these issues, can we come up with adistributed and robust algorithm to achieve the desiredreplication -- Will the system adapt to changes in systemparameters over time -- We will describe our work in tryingto answer these kinds of questions.
    Biography:Dah Ming Chiu is a professor of the Department of InformationEngineering at the Chinese University of Hong Kong (CUHK).He is currently serving as the department chairman.Dah Ming received his BSc from Imperial College London, andPhD from Harvard University. He worked in industry beforejoining CUHK in 2002.
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    Date:24/02/2011, 14h
    Room:amphi Saphir
    Speaker:Gerard Cohen (Telecom ParisTech)
    Talk:Quelques applications des codes correcteurs
    Abstract:Nous pr�sentons quelques applications exotiques des codes correcteurs � desprobl�mes d'�criture sur des m�moires, de biom�trie et de pistage de tra�tres.
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    Date:10/02/2011, 14h
    Room:amphi Saphir
    Speaker:Jean-Louis Dessalles (Telecom ParisTech)
    Talk:Pourquoi donner des informations aux autres
    Abstract:En 1978, John Krebs et Richard Dawkins, deux specialistesdes signaux dans le regne animal, ont enonce ce que l'on peut voir comme la/malediction/ de la communication : si les interets de l'emetteur et durecepteur convergent, la communication sera utile, rare et secrete ; s'ilsdivergent, elle aura une forme publicitaire : pauvre, repetitive et publique. La communication humaine semble faire exception : elle est riche, abondante etouverte (ce qui a permis a l'industrie des telecommunications de prosperer !).Mes resultats recents demontrent, par le calcul et la simulation, comment unecommunication riche peut emerger entre agents egoistes et rester stable. Pourcela, il faut plonger la communication dans un jeu social. Les pratiques decommunication 2.0 (Web, blogs, Twitter...) offrent un beau test de la theorie.
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    Date:10/02/2011, 11h-12h
    Room:LINCS, 23 av Italie (Plan d'acces)
    Speaker:Alexandre Brandwajn (University of California at Santa Cruz)
    Talk:Seeking simplicity in complex systems
    Abstract:Queueing network models are an important tool in the evaluation of the performance of computer systems and networks. Explicit analytical solutions exist for a class of such models, but features such as realistic global dependencies, priorities, or simple commonly used service disciplines, preclude their direct application. Additionally, even when such solutions are known, their numerical computation may still be challenging due to the size of the state space of classical queueing models. In this talk, we try to show that the use of conditional probabilities may be valuable in exposing simple properties hidden from view by classical state descriptions. Examples include tandem networks with blocking, multiclass models, multi-server systems with priorities, as well as guided state sampling in large systems.
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    Date:20/01/2011, 14h - 15h
    Room:Amphi B310
    Speaker:Paul Amer (University of Delaware)
    Talk:Reliable Transport Layer Protocols Should Not Be Allowed To Renege
    Abstract:Transport layer data reneging occurs when a data receiver first selectively acknowledges (SACKs) data, and later discards thatdata from its receiver buffer prior to delivering that data tothe receiving application or socket buffer. Today's reliabletransport protocols (TCP and SCTP) are designed to tolerate datareneging. For two reasons, we argue that this design assumptionis wrong. First (1) there are potential performance gains insend buffer utilization and throughput by not allowing reneging.Second (2) we hypothesize that data reneging rarely if everoccurs in practice. To support (1), we present published resultson Non-Renegable Selective Acks (NR-SACKs). To support (2), wepresent a model for detecting instances of data reneging byanalyzing traces of TCP traffic. Using this model, we are currentlyinvestigating the frequency of data reneging in Internet tracesprovided by CAIDA.
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    Date:13/01/2011, 14h - 15h
    Room:Amphi Saphir
    Speaker:Elham Kashefi (University of Edinburgh)
    Talk:Verification of Quantum Mechanics
    Abstract:Can we verify the theory of quantum mecahnics in the context of very large systems in a similar manner to the way that single particle systems have been verified to an exquisite level of accuracy ¿ Can we efficiently test the validity of quantum mechanics using only classical devices ¿ Can we prove a given device is in fact taking advantage of quantum mechanics rather than being a disguised classical machine ¿ I will describe how interactive proof system (a key concept in theoretical computer science) can be exploited to answer the above questions. Interactive proof system is an abstract machine where two parties, the verifier and the prover, interact by exchanging messages in order to ascertain whether a statement is correct. The prover (nature) is all-powerful and possesses unlimited computational resources, but cannot be trusted, while the verifier (us) has bounded computation power. I show that any quantum computation has an interactive proof with two entangled quantum provers and a completely classical verifier and also a single prover with a nearly classical verifier. These results are based on the recently proposed Universal Blind Quantum Computing Protocol (Broadbent, Fitzsimons and Kashefi, FOCS 2009).
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    Date:16/12/2010, 14h - 15h
    Speaker:Jean-Louis Rougier (Telecom ParisTech)
    Talk:Energy-Aware Routing: a Reality Check
    Abstract:In this work, we analyze the design of green routing algorithms and evaluate the achievable energy savings that such mechanisms could allow in several realistic network scenarios. We formulate the problem as a minimum energy routing optimization, which we numerically solve considering a core-network scenario, which can be seen as a worst-case for energy saving performance (as nodes cannot be switched off). To gather full-relief results, we analyze the energy savings in various conditions (i.e., network topology and traffic matrix) and under different technology assumptions (i.e., the energy profile of the network devices).These results give us insight into the potential benefits of different ``green'' technologies and their interactions. In particular, we show that depending on the topology and traffic matrices, the optimal energy savings can be modest, partly limiting the interest for green routing approaches for some scenarios. At the same time, we also show that the common belief that there is a trade off between green network optimization and performance does not necessarily hold: in the considered environment, green routing has no effect on the main network performances such as maximum link utilization.
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    Date:09/12/2010, 14h - 15h
    Room:Amphi Saphir
    Speaker:Subhabrata Sen (AT&T Labs)
    Talk:Network Management from an ISP perspective: Keeping up with the times
    Abstract:IP networks today are very large, complex systems running a wide variety of applications and services with diverse and evolving performance needs. Network management is therefore constantly being thrust into new realms, and must evolve to support such a wide range of complex services at massive scales. In this talk I shall first overview the types of problems and challenges that ISP-scale network operators have to address. I shall then present recent work in 2 specific areas of network management:Understanding Emerging Traffic Trends -Recent research analyzing worldwide Internet traffic indicates that HTTP ((Hypertext Transport Protocol) accounts for a majority of residential broadband traffic by volume. Originally developed for human-initiated client-server communications launched from web browsers running on traditional computers and laptops, today HTTP today has become the protocol of choice for a wide range of applications from a diverse array of emerging devices like smart TVs and gaming consoles. Here I shall present our study of these new sources of HTTP traffic for residential broadband Internet users.Resource Management -In an UMTS (Universal Mobile Telecommunications System) 3G network, one of the most popular 3G mobile communication technologies, a key factor affecting application performance and network resource usage is the Radio Resource Control (RRC) state machine. The purpose of the state machine is to efficiently manage limited radio resources and to conserve the handset battery life. I will explore the impact of operational state machine settings, illustrate inefficiencies caused by the interplay between smartphone applications and the state machine behavior, and explore techniques to improve performance and resource usage.
    Biography:Dr. Subhabrata Sen is a Principal Member of Technical Staff in the Networking & Services Research Laboratory at AT&T Labs-Research. He received a Bachelor of Engineering (First Class with Honors) degree in Computer Science from Jadavpur University, India, and M.S. and Ph.D. degrees in Computer Science from the University of Massachusetts, Amherst. His research interests span IP network management and include configuration management, network measurements, network data mining, traffic analysis, and network and application performance.Dr. Sen has published more than 70 research articles and owns 8 issued patents. He received the AT&T CTO Innovation Award in 2008. He is a member of the IEEE and ACM and his web page is http://www.research.att.com/~sen.
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    Date:07/12/2010, 7-9 December 2010
    Room:Telecom ParisTech
    Talk:22nd International Conference on Software & Systems Engineering and their Applications
    Abstract:Harnessing the Power and Promise of Distributed Software and SystemsWe live in a connected world - an interdependent web of economic, social and political entities. Actions of one potentially affect the behaviors of all. Whether you believe that information technology helped spawn this connected and interdependent world or merely co-evolved with it, it is clear that modern software and systems engineering has been profoundly impacted. This conference is dedicated to the development of software and systems that harness the power in this web rather than fall victim to it.The ubiquitous spread of the Internet and the World Wide Web has had a twofold impact on software and systems engineering: it has impacted the way enterprises interact with their customers and partners, and it has changed the way they develop software applications. Among the more common approaches that are being used are service-oriented architectures, web services, SAAS, cloud computing, P2P, grids, JBI and SCA. These approaches leverage the distributed nature of the systems to make them more flexible, adaptable, and better suited to users needs. In contrast to the tightly-coupled designs of older technologies, modern software and systems deliver capability through a kaleidoscope of loosely-coupled elements riding on infrastructure. Often times project management is also a distributed process. Not only are teams geographically spread, but also a team must cooperate with members outside their own organization in order to successfully complete a project. Software and systems producers can no longer act in total isolation - they must themselves become dependent on component or service providers, on VARs, and even on proactive customers.Co-organized by TELECOM ParisTech, CS Communication and Systems, and the Gnie Logiciel quarterly, the 22nd edition of the ICSSEA Conference (International Conference on Software and Systems Engineering and their Applications) will be held in Paris on December 7-9, 2010. By gathering actors from across the enterprise and research worlds, it aims at providing a critical survey of the status of tools, methods, and processes for elaborating software & systems. Lectures and discussions will be conducted with the issues of coupling and interoperability in distributed software and systems as the leitmotiv.
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    Date:07/12/2010, 14h - 15h
    Room:Amphi Saphir
    Speaker:Milind Madhav Buddhikot (Alcatel Lucent)
    Talk:Red, White and Green: Colors of the New Cellular Revolution
    Abstract:In the next few years, with rapid adoption of smart phones that allow end-users any-time, any-where Internet access, mobile data traffic is expected to increase exponentially. The wireless service providers face two main challenges as they address this new trend: (1) as the per-user throughput requirements scale to multi-Mbps, how to scale the networks to achieve dramatic improvements in wireless access and system capacity, and (2) in the face of declining ARPU and increasing competition, how to reduce cost of deploying and operating the network.This talk represents our attempt to peer into the crystal ball and predict how cognitive radio technologies, specifically Spatio-temporal demand tracking, Dynamic Spectrum Access (DSA), energy management and Self-X will help meet these challenges and usher in a new transformation in cellular networks. We discuss in detail technologies in the following key areas: (1) DSA for capacity augmentation in macro-cells, (2) Ultra-broadband small and femto cells using spectrum white spaces, (3) Self-X (X=configure, monitor, diagnose, repair and optimize) for LTE networks, and (4) Energy management. We show that the application of cognitive radio ideas to infrastructure cellular networks can bring great benefits by achieving a balance between complexity, practical realizability, performance gains and true market potential.
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    Date:03/12/2010, 16h-17h
    Room:Amphi B312
    Speaker:Marco Ajmone Marsan
    Talk:Energy Efficient Wireless Internet Accesswith Cooperative Cellular Networks
    Abstract:In this talk we discuss the energy-aware cooperative managementof the cellular access networks of the operators that offer serviceover the same area, and we evaluate the amount of energy thatcan be saved by using all networks in high traffic conditions,but progressively switching off networks during the periodswhen traffic decreases, and eventually becomes so low thatthe desired quality of service can be obtained with just one network. When a network is switched off, its customers are allowed to roamover those that remain powered on. Several alternatives are studied,as regards the traffic profile, the switch-off pattern, the energycost model, and the roaming policy.Numerical results indicate that a huge amount of energy can be savedwith an energy-aware cooperative management of the networks, andsuggest that, to reduce energy consumption, and thus the costto operate the networks, new cooperative attitudes of the operatorsshould be encouraged with appropriate incentives.
    Biography:Marco Ajmone Marsan is a Full Professor at the Electronics Department of Politecnico di Torino, in Italy, and a part-time Chief Researcher at IMDEA Networks (www.imdea.org/networks) in Madrid. He is the founder and the leader of the Telecommunication Networks Group at the Electronics Department of Politecnico di Torino.Marco Ajmone Marsan holds degrees in Electronic Engineering from Politecnico di Torino and University of California, Los Angeles.Marco Ajmone Marsan was at Politecnico di Torinou2019s Electronics Department from November 1975 to October 1987 - first as a researcher and then as an Associate Professor. He was a Full Professor at the University of Milanu2019s Computer Science Department from November 1987 to October 1990. From September 2002 to March 2009 he was the Director of the Institute for Electronics, Information and Telecommunications Engineering of the National Research Council. From 2005 to 2009 he was the Vice-Rector for Research, Innovation and Technology Transfer at Politecnico di Torino.During the summers of 1980 and 1981, he was with the Research in Distributed Processing Group, Computer Science Department, UCLA. During the summer of 1998 he was an Erskine Fellow at the Computer Science Department of the University of Canterbury in New Zealand.He has co-authored over 300 journal and conference papers in Communications and Computer Science, as well as the two books "Performance Models of Multiprocessor Systems," published by the MIT Press, and "Modelling with Generalized Stochastic Petri Nets," published by John Wiley.In 1982, he received the best paper award at the Third International Conference on Distributed Computing Systems in Miami, Florida. In 2002, he was awarded a honorary doctoral degree in Telecommunications Networks from the Budapest University of Technology and Economics. He was named Commander of the Order of Merit of the Italian Republic in 2006. He is the chair of the Italian Group of Telecommunications Professors, and the Italian Delegate in the ICT Committee of the 7th Framework Programme of the EC.He has been the principal investigator in national and international research projects dealing with telecommunication networks. His current interests are in the performance evaluation of communication networks and their protocols.Marco Ajmone Marsan is a Fellow of IEEE, and a corresponding member of the Academy of Sciences of Torino. He is a member of the steering committee of the IEEE/ACM Transactions on Networking. He participates in a number of editorial boards of international journals, including the Computer Networks Journal by Elsevier. He is listed by ISI among the highly cited researchers in Computer Science and a member of the Gruppo 2003, the association of Italian Highly Cited Scientists.
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    Date:02/12/2010, 14h - 15h
    Room:Amphi Saphir
    Speaker:Dario Rossi
    Talk:A tutorial on Green Networking
    Abstract:Reduction of unnecessary energy consumption is becoming a major concern in wired networking, in reason of both the potential economical benefits and its forecast environmental impact. These issues, usually referred to as ``green networking, relate to embedding energy-awareness in networks design, devices and protocols. In this tutorial, we first phrase a more precise definition of the ``green attribute, identifying furthermore a few paradigms that are the key enablers of energy-aware networking research. We then overview the current state of art,providing a taxonomy of the relevant work: from a high level perspective, weidentify four branches of green networking research, that stem from different observations on the root causes of energy waste. Such branches can be identified, namely, as (i) Adaptive Link Rate, (ii) Interface proxying, (iii) Energy-aware infrastructures and (iv) Energy-aware applications. The covered material will not only dig into specific proposal pertaining to one of the above branches, but also offer a perspective look on the open research point.
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    Date:02/12/2010, 14h - 15h
    Room:Amphi Saphir
    Talk:Mthodes Formelles dans le Dveloppement Logicie
    Abstract:Le groupe de travail Mthodes Formelles dans le Dveloppement Logiciel (MFDL) organise une journe de rencontre Paris. Cette journe a pour objectif de permettre aux doctorants et post-doctorants de prsenter leurs travaux de recherche et de permettre aux quipes impliques dans le groupe MFDL de montrer leurs problmatiques actuelles de recherche travers leur implication dans des projets. Programme: http://membres-liglab.imag.fr/idani/MFDL/programme.html
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    Date:30/11/2010, 30 novembre 2010
    Room:Amphi Rubis
    Speaker:Julie mac Cann
    Talk:Autonomic Computing on WSN (A Brief Story of time)
    Abstract:I will begin by briefly introducing calm computing and how it relates toWireless Sensor Networks (WSN) and Autonomic computing. Then I willpresent a very simple protocol we developed to provide self-* in WSN andshow some of its behaviours and how we optimised it. This protocol isbased on established bio-inspired approaches, therefore I'm hoping I canhighlight how easy and yet difficult adapting such techniques are,specifically on a WSN, and hope to provide some insight into how oneshould engineer emergent solutions in general.
    Biography:McCann's work centers around architectures, algorithms, protocols andtools that allow computer systems to self-adapt to their environment toimprove their performance or quality therein. She has publishedextensively in the areas of computer performance, dynamic operatingsystems, database machines and text retrieval systems. More recent workhas focused on self-adaptive and self-management of content deliverysystems, mobile computing and wireless sensor networking algorithms. Forher earlier work in text retrieval, she was recently co-awarded EmeraldLiterati Network "Highly Commended". To date, she has been PI on 13 majorgovernment/industry funded research projects, and is CI on three EPSRCNetworks of excellence. She has supervised five PhD students to successfulcompletion, examined many more and currently leads a nine strong teamresearching Self-adaptive and Bio-inspired Computing, which have developedthe Beastie wireless sensor node.All her projects are interdisciplinary, applied to the arts or engineering- collaborating with RCA; The University of the Arts; InteractiveInstitute Stockholm etc.; as well as many other industrial partnershipssuch as with Sun Microsystems, Thames and Severn Trent Water, BT, ArupEngineering and BBC to name but a few.She is an active programme committee member for many of the self-managingadaptive computing journals and conferences. She has also co-chairedconferences such as IEEE Intl. Conf. on Complex Open Distributed Systemsand the ACM Intl. Conf. on Pervasive Services 2008 and 2009 (GeneralChair). McCann is regularly invited to talk on self-adaptive computing todiverse audiences and has been an invited panel member ACM/IEEEInternational Conference in Autonomic Computing and IFIP/IEEEInternational Symposium on Integrated Network Management. She is a memberof the BCS, IEEE and a Chartered Engineer.
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    Date:18/11/2010, 18 novembre 2010
    Room:Amphi Saphir
    Speaker:Pierre Senellart (Tlcom ParisTech)
    Talk:Probabilistic XML Data Management
    Abstract:A large number of automatic tasks on real-world datagenerate imprecise results, e.g., information extraction, naturallanguage processing, data mining. Moreover, in many of these tasks,information is represented in a semi-structured way, either due to aninherent tree-like structure of the original data, or because it isnatural to represent derived information or knowledge in a hierarchicalmanner. A number of recent works have dealt with representing uncertaininformation in XML. We present a high-level overview of these works,discussing in particular models, expressiveness, and query efficiency.Finally, we aim at providing insight into important open problems for probabilistic XML, by discussing the connection with relational databasemodels, the limitations of existing frameworks, and other topics ofinterest.
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    Date:11/10/2010, Lundi 11 octobre 2010 14h
    Speaker:Mark Karpovsky (Reliable Computing Lab., Boston Univ.)
    Talk:Design of Secure Hardware Resistant to the Attacks
    Abstract:Recently several very efficient so called side-channel attacks oncryptographic devices and smartphones have been developed. The goal ofthese attacks is to learn the secret information (such as a privatekey, password, etc). For example, it takes less than a minute to breakan Advanced Encryption Standard (AES) device and get a 128-bit secretkey.I will present the design approach for reliable and secure deviceswith built-in self-protection against these attacks. When the devicedetects that it is under attack it disables itself. The approach isbased on special robust error detecting codes which we developed inour laboratory. As oppose to the classical error detecting codes forcommunication channels, the proposed robust codes have uniformlydistributed error detecting capability and provide for equalprotection against all errors. These codes can provide for a highreliability and a high security even for strong attacks when theattacker knows the code being used and can inject any error pattern.I will describe the constructions for these codes and theirapplications for design of reliable and secure hardware for computermemory, multipliers and for hardware for AES. We will present someexperimental data on the required overheads and power consumption andcompare the proposed approach based on robust codes with approachesbased on randomized linear codes.
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    Date:29/09/2010, 9h00 - 18h00
    Speaker:Chairs Maurice Gagnaire and Prof. Naoaki Yamanaka
    Talk:The First TELECOM ParisTech -- Keio University Joint Workshop on Future Networking
    Abstract: Program in PDF
    9:15 - 9:20 Opening by Prof. Maurice Gagnaire and Prof. Naoaki Yamanaka
    9:20 - 9:45 Overview of G-COE Program by Prof. Yamaguchi
    9:45 - 10:45 - Session 1 "Energy-aware networks"
    Chair: Prof. Jean-Louis Rougier
      1. "High Energy-Efficient Internet Architecture by Optical Aggregation Network", Hidetoshi Takeshita, Keio University, Japan.
      2. ."MiDORi : Energy Efficient Layer-2 Network Architecture", Shan Gao, Keio University, Japan.
      3. " Taking into account energy awareness into network optimization ", Aruna Prem Bianzino,Telecom ParisTech, France.

    10:45 - 11:45 - Session 2 "Network control and architecture"
    Chair: Prof. Naoaki Yamanaka
      4. "Routing-Protocol-Less Signaling Architecture for Connection Oriented Ethernet", Kou Kikuta, Keio University, Japan.
      5. On the impact of sampling on traffic monitoring and analysis", Davide Tammaro, Telecom ParisTech, France.
      6. "A hands-on assessment of transport protocols with lower than Best-Effort priority", Claudio Testa, Telecom ParisTech, France.
    11:45 - 12:25 - Session 3 "Optical networks design" Chair: Prof. Yves Jaouen
      7. "Impairment-aware optical network design", Mayssa Youssef, Sawsan Al Zahr, Telecom ParisTech, France
      8. "Failure localization in optical networks", Elias Doumith, Sawsan Al Zahr, Ahmed Haddad, Telecom ParisTech, France.
    12:25 - 13:45 Lunch break
    13:45 - 14:45 - Session 4 "Mobile Network Architecture"
    Chair: Prof. Philippe Martins
      9. "Upper bound for the dimensioning of OFDMA systems", Tung Vu Telecom ParisTech, France.
      10. "Multi-hop Cooperative Routing in Spectrum Sharing Networks", I-Te Lin, Keio University, Japan.
      11. "Cognitive beacon channel via GSM and UMTS", Rodrigo Soule de Castro;Telecom ParisTech,France.
    14:45 - 16:30 Visit of the optical devices and systems Laboratory by Prof. Yves Jaouen
    16:30 - 17:30 - Session 5 "Wireless Communications"
    Chair: Prof. Masayasu Yamaguchi
      12. Precoded Transmit Path Diversity in FS-OFDM, Haruki Nishimura, Keio University, Japan.
      13. "Capacity gains of some frequency reuse schemes in OFDMA networks", Thomas Bonald,Telecom ParisTech, France.
      14. Reduced Complexity in Antenna Selection for Polarized MIMO Communication Channel Environment, Maung Sann Maw, Keio University, Japan.
    17:30 - 17:45 Closing and Wrap-up
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    Date:09/09/2010, Jeudi 9 septembre 2010 14h
    Speaker:Simon Litsyn (EE-Systems, Tel Aviv University)
    Talk:A la recherche du temps et de la position perdus
    Abstract:For a binary (plus/minus one) finite sequence, the peak sidelobelevel (PSL) is defined as the maximum, over nonzero shifts, of thescalar product of the sequence with its aperiodically shifted version.Binary sequences with low PSL are of importance for synchronizationin TIME and determining POSITION and distance to an object. Intheoretical physics, study of the PSL landscape was introduced byBernasconi via the so-called Bernasconi model, which is fascinatingfor the fact of being completely deterministic, but neverthelesshaving highly disordered ground states (sequences with the lowest PSL)and thus possessing striking similarities to the real glasses (spinglass models), with many features of a glass transition exhibited. The problem of designing and characterizing sequences with low PSLhas been attacked for at least fifty years, however our knowledgeis still far from being satisfactory. In the talk I will survey the main open issues and report onseveral new results:- We show that the typical PSL of binary sequences is proportional to sqrtn ln n, thus improving on the best earlier known result due to Moon and Moser and settling to the affirmative a conjecture of Dmitriev and Jedwab;- We show that the maximum of PSL in m-sequences is proportional to 2^m/2 ln m, thus disproving a long-standing conjecture of it being 2^m/2.The results are partly due to cooperation with N. Alon,Ye. Domoshnitsky, A. Shpunt and A. Yudin.
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    Date:15/07/2010, 14h - 15h
    Room:LiNC Interdisciplinary Communications Laboratory, 23 av Italie (Plan d'acces)
    Speaker:Lavy Libman, University of Sydney
    Talk:Towards Optimal Forwarding in Wireless Networks: Opportunistic Routing Meets Network Coding
    Abstract:In wireless networks, transmissions can be overheard by unintended nodes in the vicinity of the sender and receiver, potentially causing interference to their own communications. The research literature abounds with "solutions" that attempt to overcome the interference using scheduling, channel assignment, and many other mechanisms. On the other hand, in recent years, there has been growing attention to methods that aim to take advantage of the broadcast nature of the wireless medium and the ability of nodes to overhear their neighbors' transmissions. Two of the most important such methods are opportunistic routing (OR) and wireless network coding (NC). In this talk, I overview the principles of these methods and study the potential benefits of forwarding schemes that combine elements from both the OR and NC approaches, when traffic on a bidirectional unicast connection between two nodes is relayed by multiple common neighbors. In particular, I will present a dynamic programming algorithm to find the optimal scheme as a function of link error rates, and demonstrate that it can achieve up to 20% reduction in the average number of transmissions per packet compared to either OR or NC employed alone, even in a simple scenario of two common neighbors between the connection endpoints.
    Biography:Lavy Libman is a senior lecturer in the School of Information Technologies, University of Sydney, which he joined in February 2009. He also continues to be associated with the Networked Systems research group at NICTA (formerly National ICT Australia), where he was a researcher since September 2003. He is currently serving as a TPC co-chair of ICCCN 2010 and WiOpt 2010, a guest editor of the Journal of Communications (JCM) special issue on Road and Vehicular Communications and Applications, and is regularly involved in the committees of several other international conferences. He is an IEEE senior member and holds a PhD degree in Electrical Engineering from the Technion - Israel Institute of Technology since 2003. His research revolves around the design and optimization of wireless and mobile networks, with a particular interest in cooperative and opportunistic techniques and game-theoretic modeling.
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    Date:08/07/2010, 14h - 15h
    Room:Amphi Saphir
    Speaker:Joseph Boutros (TAMUQ)
    Talk:Construction de rseaux euclidiens par l'inverse de leur matricegnratrice
    Abstract:Nous considrons les rseaux euclidiens, c--d des Z-modules de rang ndans R^n.Plusieurs constructions de ces rseaux sont connues :- Construction partir de codes dfinis sur des corps finis,- Construction du rseau partir de son groupe d'automorphismes,- La thorie du collage o le rseau est la somme directe de sous-rseaux,- La construction par couche donnant lieu aux rseaux lamins,- et plus rcemment les rseaux dits LDLC (Low-Density Lattice Codes) ol'inverse de la matrice gnratrice du rseau est creuse.Nous dcrivons une nouvelle construction de rseaux reels (LDLCet non LDLC) ayant une diversit maximale pour le dcodage maximumde vraisemblance. Ensuite, en examinant l'image binaire de la matricedu rseau, nous tablissons une deuxime construction de rseaux reelsLDLC ayant une diversit maximale pour le dcodage probabiliste itratif.
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    Date:05/07/2010, 15h
    Speaker:Oleg Sokolsky (U. Penn.)
    Talk:A Process Algebraic Framework for Modeling Resource Demand and Supply
    Abstract:Resource partitioning is increasingly used in the development ofreal-time and embedded systems to enable independent development ofresource-aware components, ensure performance of components as well astheir independence. Several analytical techniques based on real-timescheduling theory have been proposed in the literature. Thesetechniques are defined for specific task models and are hard togeneralize. On the other hand, scheduling analysis techniques based onformal methods are much applicable to arbitrary task models. However,existing approaches are limited to modeling task demand and assume fullresource availability. In this work, we present a formal model forresource design and supplies inspired by the process algebra ACSR. Weexplicitly represent requested as well as granted resources and defineparallel composition of tasks and supplies by matching resource requestswith resource grants. Based on these notions, we develop acompositional theory for schedulability analysis.
    Biography:Oleg Sokolsky is a Research Associate Professor at the University ofPennsylvania Department of Computer and Information Science. He hasstudied a wide variety of topics related to the development ofhigh-assurance embedded and real-time systems, in particular theapplication of formal methods to timing analysis. He has received Ph.D.in Computer Science from Stony Brook University in 1996.
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    Date:01/07/2010, 14h - 15h
    Room:Amphi Saphir
    Speaker:Laurent Decreusefond
    Talk:Finance for dummies
    Abstract:Produits drivs : vous en avez entendu parler, on vous a dit que c'tait desmathmatiques super-compliques. En fait, pas forcment. On essaiera ici demontrer qu'on peut tout de mme en comprendre les principes sous-jacents avecdes outils simples tels que les systmes linaires deux quations et deuxinconnues, le jeu de pile ou face, une pince de gomtrie dans le plan.
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    Date:16/06/2010, 9h00 - 17h30
    Room:Amphi B312
    Conference:6eme journe Optimisation des rseaux
    Talk:6eme journe Optimisation des rseaux, organise conjointement par Tlcom ParisTech et le groupe Optimisation les rseaux (GT du GdR RO et de la ROADEF)
    Abstract:La vocation de ce groupe est d'offrir des possibilits d'changesentre chercheurs acadmiques et industriels, autour de thmes lis l'optimisation des rseaux dans tous les domaines d'application : - eau, - nergie, - logistique, - tlcommunications, - transport, - etc. Les rseaux modlisent des problmes dont la rsolutionfait appel divers domaines de l'optimisation : - mathmatiquesdiscrtes, - mthodes exactes ou approches, - modle de flot et demultiflot, - optimisation continue, - optimisation dterministe etstochastique, - programmation linaire et non linaire, - thoriedes graphes, - etc.Faisant suite aux prcdentes rencontres (27 octobre 2006 l'Institut Henri Poincar, 25 octobre 2007 Gaz de France, 14 mai2008 Orange Labs R&D, 13 octobre 2008 l'cole nationale desponts et chausses, 9 septembre 2009 l'Union internationale deschemins de fer), cette journe s'adresse aux chercheurs, tudiantset industriels qui souhaitent partager leurs points de vue et leursattentes sur l'optimisation dans les rseaux.L'inscription est gratuite mais obligatoire. Si vous souhaitezassister cette journe, nous vous invitons vous faire connatreaussi rapidement que possible en envoyant vos nom, prnom etaffiliation Olivier Hudry, l'adresse hudry [at] enst [dot] fr.Si vous souhaitez y prsenter une communication (environ 30minutes), merci de prciser en outre un titre (un rsum dequelques lignes sera aussi prvoir, mais il pourra tre envoyultrieurement).Les renseignements sur le programme de la journe et l'accs Tlcom ParisTech seront prciss ultrieurement.
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    Date:10/06/2010, 14h - 15h
    Room:Amphi Saphir
    Speaker:Igor Shparlinski
    Talk:On Pairing Friendly Elliptic Curves and Fields
    Abstract:We present some theoretic and heuristic estimates for the number ofelliptic curves with low embedding which is essential for theirapplicability in pairing based cryptography. We also give estimatesfor the number of fields over which such curves may exist. The mainideas behind the proofs will be explained as well. Finally, we give aheuristic analysis of the so-called MNT algorithm and show that itproduces a rather "thin" sequence of curves..
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    Date:03/06/2010, 14h - 15h
    Room:Amphi Saphir
    Speaker:Elie Najm
    Talk:Service Orchestration with Orcharts and Typecharts
    Abstract:We discuss a novel approach for the sound orchestration of services,based on expressing jointly behaviours and their types. We introduceOrcharts, a behaviour language for service orchestration and Typecharts,an associated behavioural typing language. Sessions play a pivotalrole in this approach. Orcharts (orchestration charts) define sessionbased services and Typecharts provide for session types with complexinteraction patterns that generalise the request/response interactionparadigm. We provide an algorithm for deciding behavioural welltypedeness and discuss the properties of well typed Orcharts.(Joint work with Alessandro Fantechi).
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    Date:27/05/2010, 14h - 15h
    Room:Amphi Saphir
    Speaker:Michel Kieffer (Universit Paris-Sud et Telecom ParisTech)
    Talk:Joint Protocol-Channel Decoding
    Abstract:Robust reception of audiovisual signals (and especially video) has been widely studied, demonstrating that the socalled Joint Source and Channel Decoding (JSCD) approach could improve the receiver performance while being compatiblewith existing standards (in fact they make the best possible use of the received data). However, in contrast with most approaches dealing with the cross layer strategy, JSCD does not take into account the actual structure of the communication chain, in which the network layers packetize the data, add headers, etc. Several consequences resulted from this fact: (i) JSCD is not making use of redundancies that are introduced by the network layers, e.g., CRCs, even if this redundancy may be quite large; (ii) JSCD is implicitlyassuming that a large part of the actual bitstream (essentially headers of all sorts) was received without errors; (iii) JSCD in its initial statement is not compliant with most transmission systems.This talk will introduce Joint Protocol and Channel Decoding (JPCD), to be used jointly with JSCD, which aims is to solve these inconsistencies. More specifically, the talk will focus on two problems adressed using JPCD, namely reliable packet synchronisation and header recovery. In both cases, JPCD exploits the redundancy present in the protocol stack to improve the performance of data transmission over wireless networks.
    Biography:Michel Kieffer obtained in 1995 the Agregation in Applied Physics at the Ecole Normale Superieure de Cachan, France. He received a PhD degree in Control and Signal Processing in 1999, and the HDR degree in 2005, both from the Univ Paris-Sud, Orsay, France.Michel Kieffer is an assistant professor in signal processing for communications at the Univ Paris-Sud and a researcher at the Laboratoire des Signaux et Systemes, CNRS - SUPELEC - Univ Paris-Sud, Gif-sur-Yvette, France. From sept. 2009 to sept. 2010, he has been invited professorat the Laboratoire Traitement et Communication de l
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    Date:26/05/2010, 15h00
    Room:Amphi Grenat
    Speaker:Mario Gerla, UCLA
    Talk:Pipeline Network Coding for Multicast Streams
    Abstract:The talk presents the performance of pipeline network coding for multicast stream distribution in high loss rate MANET scenarios. Most of the previous network coding implementations have been based on batch network coding, where all blocks in the same batch are mixed together. Batch coding requires that the entire batch is received before decoding at destination. Thus, it introduces high decoding delays that impact the stream reception quality. Instead of waiting for the entire batch (i.e., generation), pipeline network coding encodes/decodes packets progressively. Consequently, pipeline network coding yields several benefits: (1) reduced decoding delay, (2) further improved throughput, (3) transparency to higher layers (UDP, TCP, or other applications), (4) no special hardware support and (5) easier implementation. We show performance gain of pipeline coding compared to batch coding via extensive simulation experiments.
    Biography:Dr. Gerla was born in Milan, Italy. He received a graduate degree in engineering from the Politecnico di Milano, in 1966, and the M.S. and Ph.D. degrees in engineering from UCLA in 1970 and 1973, respectively. He joined the Faculty of the UCLA Computer Science Department in 1977. His research interests cover the performance evaluation, design and control of distributed computer communication systems and high speed computer networks (B-ISDN and Optical Networks).
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    Date:20/05/2010, 14h - 15h
    Room:Amphi Saphir
    Speaker:Jean-Louis Dessalles
    Talk:La thorie de la simplicit - Application la probabilit subjective et la pertinence des vnements.
    Abstract:En 1999, Nick Chater publia un article fondateur intitul : /The search for simplicity: A fundamental cognitive principle/ Il est probable qu' l'poque, il ait mme sous-estim la porte de ce principe de simplicit, dont nous commenons mesurer l'importance, jusque l insouponne, dans la slection et l'organisation des informations traites par notre cerveau. Le principe de simplicit permet de faire des prdictions qualitatives et quantitatives dans des domaines traditionnellement rputs opaques la modlisation. Par exemple, les vnements que nous trouvons intressants (improbables, motionnels, dignes d'tre communiqus) s'accompagnent systmatiquement d'un contraste de complexit. La thorie de la simplicit dbouche sur une redfinition de la notion d'information.Site de la thorie de la simplicit : http://www.simplicitytheory.org
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     to be confirmed
    Date:13/05/2010, 14h - 15h
    Room:Amphi Saphir
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    Date:06/05/2010, 15h-16h
    Room:amphi Saphir
    Speaker:Eduardo Ferraz (Telecom ParisTech)
    Talk:Algebraic topology applied to random sensor networks
    Abstract:We investigate some statistical features of simplicial complexes generatedby homogeneous Poisson point processes. To do that, we consider that thepoints of a homogeneous Poisson point process generates a Rips complex insome region, so we can use some results from algebraic topology as wellas some tools concerning the Poisson space, such as Malliavin calculus and concentration inequalities. We obtain the limit of distributions of numberof k-simplices, Betti numbers and Euler characteristics. Besides, we find some statistics of the studied quantities, like the mean and variance ofk-simplices and the mean of the Euler characteristics. The simplicialcomplex represents the simplest protocol of decentralized sensor networkswhere sensors can only receive/transmit theirs ID's from/to close sensors.
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    Date:06/05/2010, 13h30-14h30
    Room:amphi Saphir
    Speaker:Murad S. Taqqu (Boston University)
    Talk:Self-similarity and computer network traffic
    Abstract:Ethernet local area network traffic appears to be approximatelystatistically self-similar. This discovery, made about twenty years ago,has had a profound impact on the field. I will try to explain whatstatistical self-similarity means, how it is detected and indicate howone can construct random processes with that property by aggregating alarge number of "on-off" renewal processes. If the number ofreplications grows to infinity then, after rescaling, the limit turnsout to be the Gaussian self-similar process called fractional Brownianmotion. But if one looks at very large time scales, then one obtainsinstead a Levy stable motion which is a process withindependent increments, infinite variance and heavy tails.The lecture, which is an overview on this subject, will be in French.
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    Date:15/04/2010, 14h - 15h
    Room:Amphi Saphir
    Speaker:Nouha Oualha (Telecom ParisTech)
    Talk:Scurit et coopration pour le stockage de donnes pair--pair
    Abstract:L'intrt pour les protocoles et les algorithmes auto-organisantsqui s'est manifest notamment avec la popularit des services de partagede fichiers (/file sharing/) ou VoIP concerne maintenant un plus largedomaine d'applications. En particulier, il a favoris l'essor desservices de stockage pair--pair (P2P). Ces services permettentl'utilisation efficace de tout espace disque libre et inexploit pourconstruire un systme de stockage fiable, disponible, passant l'chelle et avec des cots d'entretien rduits. Le stockage P2P suscitecependant des enjeux de scurit qui doivent tre traits, enparticulier en ce qui concerne l'gosme des pairs qui est en cause duparasitisme (/free-riding/) dans le systme. L'observation continue ducomportement des pairs par le contrle rgulier du stockage est unecondition importante pour scuriser un tel systme contre ces attaques.Dtecter l'gosme des pairs exige des primitives appropries comme lespreuves de possession de donnes, une forme de preuve de connaissanceavec laquelle le pair de stockage essaye interactivement de convaincrele vrificateur qu'il possde les donnes sans les envoyer ou les copierchez le vrificateur. Dans ce sminaire, nous proposons et passons enrevue plusieurs protocoles de vrification. Nous tudions en particuliercomment la vrification et la maintenance de donnes peuvent tredlgues des pairs volontaires afin de mitiger la dynamicit despairs. Nous proposons alors deux mcanismes, l'un bas sur la rputationet l'autre sur la rmunration, pour imposer la coopration au moyen detelles preuves de possession de donnes priodiquement fournies par lespairs assurant le stockage. Nous valuons l'efficacit de tellesincitations avec des modles de la thorie des jeux. Nous discutons enparticulier l'utilisation des jeux non-coopratifs Baysiens rptsainsi que celle des jeux volutionnaires.
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    Date:08/04/2010, 14h - 15h
    Room:Amphi Saphir
    Speaker:Ada Diaconescu (Telecom ParisTech) + Sylvain Frey (ImperialCollege, London)
    Talk:Conflict Resolution as an Autonomic Computing Paradigm
    Abstract:The Autonomic Computing vision (www.research.ibm.com/autonomic) aims attackling the increasing complexity, heterogeneity and scale of softwaresystems by enabling computing systems to manage themselves, whileminimising the need for human intervention. The success of this visionis becoming critical to the computing domain and consequently to oursociety, which increasingly relies on computerised systems. Nonetheless,the actual design and implementation of autonomic systems remains, tothis day, a great challenge.The objective of our research is to design and implement genericarchitectures and frameworks for facilitating the development andevolution of autonomic management solutions. Defining such reusableframeworks raises new challenging issues, not least because we aredealing with dynamic, non-deterministic and sometimes conflictingreasoning processes. When autonomic systems must react to complicatedand unpredictable scenarios, the space of detectable conditions anddesirable decisions grows exponentially. In these cases, it becomesdifficult, or impossible, to statically predict all possible situationsand provide all necessary solutions in one central controller. Theapproach where developers fully specify and control the overallapplication behaviour is in such cases hard to apply.To address these challenges, we propose to build complex administrativestrategies by opportunistically integrating simple, specializedautonomic elements. A precise, exhaustive specification of all controldirectives (e.g. monitoring, analysis, planning and execution) is nolonger required. The essential difficulty of the proposed approachconsists in ensuring that the resulting management reactions conform tothe required system behaviour. Different approaches are possible fordesigning and implementing the required integration functionalities(e.g. conflict resolution and synchronisation). These range fromcentralised solutions with a unique control point to completelydecentralised solutions relying on specific communication protocols. Aservice-oriented approach was adopted for defining and developing sucharchitectures, considering the inherent modularity and loose-couplingcharacteristics of the service paradigm.The presentation will be structured in two parts. First, we willintroduce the Autonomic Computing domain and the associated solutiondevelopment problems. Various possible architectures that implement ourvision for addressing these problems will be introduced and compared.Second, we will focus on one of these architectures, exploring acompletely decentralised design for the conflict resolution aspect. Thepresentation will detail this architecture and its correspondingprototype implementation, testing scenario and initial results. Thesample application considered for experimentation consists of asimulated home with manageable devices and conflicting temperature andelectricity consumption goals.
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    Date:02/04/2010, 10h00 - 16h30
    Room:Amphi Thvenin
    Talk:Sminaire Codage, Cryptologie, Algorithmes (CCA)
    Abstract:10h00-11h00 : Ben Smith (INRIA Saclay) - Another look at genus 2 curves
    11h15-12h15 : Caroline Fontaine (CNRS-LabSTICC/Telecom Bretagne) - Codes de Tards et Fingerprinting
    14h15-15h15: Maximilien Gadouleau (Universit de Reims)- Codage rseau linaire et affine
    15h30-16h30: Christophe Chabot (Universit de Rennes 1) - Codes quasi-cycliques et polynmes coefficients matriciels

    Programme dtaill :
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    Date:01/04/2010, 14h00 - 16h00
    Room:Amphi Saphir
    Speaker:C. Testa and S. Valenti (Telecom ParisTech)
    Talk:News from the Internet congestion control world
    Abstract:A few months ago, BitTorrent developers announced that the transfer oftorrent data in the official client was about to switch to a newapplication-layer congestion-control protocol using UDP at thetransport-layer. This announcement immediately raised an unmotivated buzzabout a new, imminent congestion collapse of the whole Internet. As this newprotocol, which undergoes the name of LEDBAT for Low Extra Delay BackgroundTransport, aims at offering a /lower/ than best effort transport service,this reaction was not built on solid technical foundation. Nevertheless, alegitimate question remains: whether this new protocol is a necessarybuilding block for future Internet applications, or whether it may result inan umpteenth addition to the already well populated world of Internetcongestion control algorithms.We tackle the issue of LEDBAT investigation using two complementaryapproaches. On the one hand, we implement the novel congestion control algorithm and investigate its performance by means of packet-levelsimulations. Considering a simple bottleneck scenario, where the newBitTorrent competes against either TCP or other BitTorrent flows, weevaluate the fairness of resource share as well as the protocol efficiency. Our results show that the new protocol successfully meets some of itsdesign goals, as for instance the efficiency one. At the same time, we alsoidentify some potential fairness issues, that need to be dealt with.On the other hand, we use an empirical approach and perform an experimentalcampaign on an active testbed. With this methodology, we study differentflavors of the LEDBAT protocol, corresponding to different milestones in theBitTorrent software evolution. Focusing on single flow scenario, weinvestigate emulated artificial network conditions, such as additionaldelay and capacity limitation. Then, in order to better grasp thepotential impact of LEDBAT on the current Internet traffic, we consider amultiple flow scenario, and investigate the performance of a mixture ofTCP and LEDBAT flows, so to better assess what ``lower-than best effort''means in practice.Overall, our results show that LEDBAT has already fulfilled some of its original design goals, though some issues (e.g., fairness and level of lowpriority) still need to be addressed. Finally, we point out that end-userswill be the final judges of the new protocol: therefore, further researchshould evaluate the effects of its adoption on the performance of theapplications ultimately relying on it.
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    Date:25/03/2010, 9h00 - 18h00
    Room:Amphi B312
    Conference:XV FORUM NTIC: SeriousGames
    Talk:Jeux srieux, ralit virtuelle et ralit augmente
    Abstract:8h30-9h00: Accueil des participants
    9h00 - 9h15: Allocutions de bienvenue
    Hlne Fontaine - INRETS et Grard Memmi - Telecom ParisTech
    9h15 - 9h45: Environnements informatiques pour l'apprentissage humain :
    Quoi de neuf
    Jean-Marc Labat - LIP6
    9h45 - 10h15: Ralit virtuelle, augmente, mixte et interaction 3D
    Philipe Fuchs - cole des Mines de Paris
    10h15-10h45: Pause
    10h45 - 11h15: Simulateurs de formation pour les conducteurs de trains
    Serge Jung - Corys
    11h15 - 11h45: Formation la manoeuvre maritime
    Herv Baudu - EMMN et Transas
    11h45 - 12h15: SCANeR : produit logiciel pour des simulateurs de formation laconduite
    Gilles Galle - Oktal
    12h15-14h00: Djeuner
    14h00 - 14h30: Mthode de dveloppement de jeux srieux pour le contrlearien
    Serge Causse - ENAC et Jean-Yves Plantec - IODE Consulting
    14h30 - 15h00: SIMVIZ : simulation en temps rel de gestion de trafic et d'accidents l'attention des concepteurs et exploitants de tunnels
    Fabrice Carr et Jean-Paul Digeon - SC2X
    15h00 - 15h30: iCAT : formation du personnel des salles de contrle Maastricht
    Hermann Baret - Eurocontrol et Randall Roberts - KTM Advance
    15h30-16h00: Pause
    16h00 - 16h30: SE-* : Gnration d'environnements synthtiques pour la supervision d'infrastructures (simulation, prototypage et formation)
    Fabien Flacher et Christian Meyer - Thals Transportation Systems
    16h30 - 17h00: GVT, environnement virtuel de formation la maintenance
    Michel Fornos - Nexter Training
    17h00 - 18h00: Table ronde anime par Jean-Marc Labat avec le concours des orateurs
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    Date:18/03/2010, 14h - 15h
    Room:Amphi Opale
    Speaker:Alain Couvreur (INRIA)
    Talk:Codes gomtriques
    Abstract:Les codes gomtriques ont t introduits au dbut des annes 80par le mathmaticien et ingnieur Russe V.D. Goppa. Dans les annesqui ont suivi ils se sont avrs tre un sujet de recherche aussifructeux que passionnant.Dans cet expos nous commencerons par prsenter les rudiments de lathorie des codes correcteurs d'erreurs puis des codes gomtriquessur des courbes algbriques. Dans un second temps, nous nousfocaliserons sur la thorie des codes sur les surfaces, la foismoins comprise et nettement moins explore et prsenterons desmthodes gomtriques d'estimation des paramtres de tels codes etde leurs duaux
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    Date:11/03/2010, 15h30 - 16h30
    Room:Amphi Saphir
    Speaker:P. Rigaux (LAMSADE, Universit Paris Dauphine)
    Talk:Nouvelles techniques de stockage, d'indexation et detraitement de donnes massives.
    Abstract:Avec le dveloppement du Web, le volume des donnes manipulespar les moteurs de recherche, les sites de commerce lectronique ou lessites communautaires rassemblant des millions d'utilisateurs, a atteintdes niveaux indits: le traoctets est un ordre de grandeur courant,bientt ce sera le ptaoctets. De nouvelles techniques de gestion de cesdonnes massives ont merg rcemment, sous l'impulsion notamment desentreprises (Google, Amazon) directement confrontes aux problmes lis ces volumes indits.L'expos sera consacr ces nouvelles techniques, en mettant l'accentsur les solutions s'appuyant sur la distribution du stockage et destraitements dans des parcs de machines extensibles. Les problmes depassage l'chelle, de fiabilit, de scurit, de reprise sur panne etde cohrence seront voqus. Je prsenterai quelques solutions-phares,fortement influences par quelques articles publis rcemment par lesquipes de Google (GFS, Bigtable, MapReduce). Enfin, le projet Hadoop,qui fournit une plate-forme Open Source implantant ces techniques, serabrivement introdui.
    Note:Joint seminar with BIlab http://bilab.enst.fr
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    Date:11/03/2010, 16h30 - 17h30
    Room:Amphi Saphir
    Speaker:K. Chine (Cloud Era Ltd)
    Talk:Cloud Computing, logiciel libre et science ouverte,vers une plateforme universelle pour le calcul scientifique et statistique.
    Abstract:Le prsentation sera un survol des cas d'utilisation cls etdes grandes lignes de l'architecture de la nouvelle plateformelogicielle Biocep-R (www.biocep.net) et sera suivi de dmonstrations.Btie autour des environnements de calcul mathmatique et statistiquetels que R et Scilab, la plateforme Biocep-R amliore de faon trssignificative l'accessibilit du calcul haute performance sur lesgrilles et les Clouds. Elle cre un environnement ouvert, o il devientfacile de concevoir, de partager et de rutiliser tout ce que le calculmet en jeu et place la collaboration au coeur des outils des sciencescomputationnelles et de fouille de donnes. Par exemple, il devientpossible chacun, partir de sa machine personnelle (ou de soniPhone), de lancer une machine virtuelle de son choix sur le cloudd'amazon et de l'utiliser pour avoir dans son navigateur, unenvironnement complet et collaboratif d'analyse de donnes qui combineles outils tel que R avec des panneaux graphiques interactifs, desfeuilles de calcul collaboratives, des interfaces graphiques analytiquescomposables par glisser-dposer et redistribuables, des outils deprsentation distance, etc.Biocep-R est aussi une bote outils qui permet de dployer des groupesde moteurs de calculs distribus avec ou sans tat sur desinfrastructures htrognes. Ces moteurs peuvent tre utiliss soit pourbtir des applications web contenu analytique dynamique qui tiennent l'chelle soit pour du calcul parallle sur des donnes massives soitpour exposer automatiquement (par introspection) des fonctions et desmodles sous forme de Services Web ou de noeuds pour des plateformes deWorkflow.
    Note:Joint seminar with BIlab http://bilab.enst.fr
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    Date:11/03/2010, 14h - 15h
    Room:Amphi Saphir
    Speaker:X. Grehant (Tlcom ParisTech)
    Talk:Allocation de ressources en grilles de calcul et clouds
    Abstract:Le "cloud" se construit sur la base de services isols, quipeuvent tre agrgs selon leurs interfaces et leurs niveaux devirtualisation bien dfinis. Les grilles de calcul, l'inverse,runissent des ressources et des applications de multiples institutions.Elles permettent une grande flexibilit dans la distribution des tcheset des donnes. Nous mettrons en parallle les diffrents types degrilles et leurs applications. Dans leur forme la plus gnrale, lesgrilles soulvent des problmes de passage l'chelle etd'htrognit des ressources et des tches. Mais leur problme le plusfondamental est celui de l'indpendance des participants. Nousanalyserons en particulier l'volution des grilles du CERN, d'unegestion uniformise des ressources une spcialisation des systmesd'allocation et une interoprabilit sur le modle du cloud.
    Note:Joint seminar with BIlab http://bilab.enst.fr
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    Date:25/02/2010, 14h - 15h
    Room:Amphi Saphir
    Speaker:Romain Allaume (Telecom ParisTech et co-fondateur de lastart-up SeQureNet)
    Talk:Cryptographie et Information Quantique
    Abstract:Les lois qui rgissent le comportement de la matire et de la lumire l'chelle atomique ou l'chelle de quelques photons diffrent decelles de la physique dite classique. Il faut en effet appliquer laphysique quantique et son formalisme, et les progrs de cette thorieont permis, au cours du 20eme sicle, de dvelopper avec succs desapplications essentielles notres socit de l'information tels que lelaser ou le transistor.L'information quantique est un domaine de recherche qui a commenc sedvelopper dans les annes 70, la frontire entre l'informatique et laphysique. L'ide est d'analyser dans quelle mesure le fait d'utiliser del'information code sur des tats quantiques (on peut dfinir la notionde bit quantique reprsentant l'tat d'un systme 2 niveaux) peutpermettre de raliser de nouvelles tches dans le domaine du calcul etdes communications.Les rapides avances de la recherche en information quantique sont denature bouleverser notre comprhension ainsi que notre faon de fairede la cryptographie : en 1994, Peter Shor a dmontr que le problme dela factorisation tait un problme facile, dans le cadre du calculquantique. Ce rsultat fondamental claire d'un jour nouveau le"paysage cryptographique classique", et le thme de Post-QuantumCryptography est dsormais tout en haut de la liste de la communautcryptographique internationale. Par ailleurs, la distribution quantiquede cl a connu un formidable essor depuis la proposition du premierprotocole, BB84, par Charles Bennett et Gilles Brassard, en 1984. Cettetechnologie est en passe de devenir la premire application industriellede l'information quantique, et trouvera ses applications dans laconstruction d'architectures numriques de trs haute scurit.Durant cet expos, j'voquerai en particulier les rsultats majeursobtenus dans le cadre du projet europen FP6 SECOQC, auquel l'quiped'information quantique de Telecom ParisTech a apport une contributionde tout premier ordre. Je discuterai galement des rsultats obtenusdans nos autres axes de recherches, mlant information quantique etcryptographie et des projets en cours, et notamment la plateforme"Scurit Quantique". Enfin, je prsenterai la spin-off SeQureNet,start-up que j'ai confond en 2008, et qui vise commercialiser desapplications de haute scurit bases sur la distribution quantique decls.
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    Date:18/02/2010, 14h - 15h
    Room:Amphi Saphir
    Speaker:Thomas Bonald (Tlcom ParisTech)
    Talk:Is congestion control critical for the future Internet
    Abstract:In this talk we seek to characterize the behaviour of the Internet in theabsence of congestion control. More specifically, we assume all sourcestransmit at their maximum rate and recover from packet loss by the use ofsome retransmission or erasure coding mechanism. We estimate theefficiency of resource utilization in terms of the maximum load thenetwork can sustain, accounting for the random nature of traffic.Contrary to common belief, there is generally no congestion collapse.Efficiency remains higher than 90% for most network topologies as long asmaximum source rates are less than link capacity by one or two orders ofmagnitude. Moreover, a simple fair drop policy enforcing fair sharing atflow level is sufficient to guarantee 100% efficiency in all cases.
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    Date:11/02/2010, 14h - 15h
    Room:15h - 17h
    Speaker:Michal Aupetit and Sylvain Lespinats (CEA, LIST "Laboratoire Intelligence Multi-capteurs et Apprentissage")
    Talk:La visualisation multidimensionnelle pour l'analyse exploratoire de donnes
    Abstract:Dans de nombreux cas, les donnes que l'on veut comprendre peuvent se reprsenter comme un nuage de points dans un espace multidimensionnel.Lorsque ces donnes sont reprsentes dans le plan, la visualisation est un moyen efficace d'extraire des informations de nature statistique, gomtrique et topologique. Lorsque les donnes ne se reprsentent pas naturellement dans le plan, il existe deux voies d'analyse possibles.D'une part, les mthodes de projection dans le plan et d'autre part, les mthodes d'analyse in situ dans l'espace multidimensionnel. Toutes deux posent le problme de l'intelligibilit de la reprsentation ainsi construite.La premire partie de cet expos est ddie aux mthodes de projection.Nous prsenterons quelques mthodes (linaires et non-linaires) classiques et moins classiques. En particulier, nous introduirons la mthode DD-HDS (Data-Driven High Dimensional Scaling) qui se fixe pour objectif la prservation des distances entre donnes, et la mthode RankVisu qui se focalise sur la prservation des rangs de voisinage.Enfin, nous voquerons Classimap qui tient compte d'informations additionnelles (comme l'appartenance des classes) pour la projection.Dans la seconde partie, nous prsenterons le paradigme de la visualisation multidimensionnelle in situ, qui dfinit un cadre dans lequel les projections planes de donnes multidimensionnelles sont interprtables. Nous montrerons que les mthodes de projection non-linaires (type ISOMAP, MDS, Sammon, LLE, KPCA, SOM...) telles qu'elles sont habituellement employes ne sont en gnral pas utilisables pour infrer sans erreur des proprits des donnes originelles. Nous montrerons comment replacer ces mthodes dans le cadre in situ pour leur rendre tout l'intrt qu'elles mritent.Plusieurs exemples sur des donnes de grande dimension seront prsents, et nous discuterons des problmes ouverts dans ce domaine.
    Note:Joint seminar with BIlab http://bilab.enst.fr
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    Date:04/02/2010, 14h - 15h
    Room:Amphi Saphir
    Speaker:Cline Chevalier (Tlcom ParisTech)
    Talk:Cryptographie distribue base de mots de passe
    Abstract:Dans la cryptographie clef publique distribue usuelle, chaqueutilisateur choisit une clef prive de taille donne et publie la clefpublique associe. Dans le cas du chiffrement ElGamal par exemple, la clefpublique est alors le produit de ces clefs publiques, et la clef prive lasomme des clefs prives, ce qui permet de faire du dchiffrementdistribu. Mais il est illusoire en pratique de demander desutilisateurs de retenir de grandes clefs de forte entropie.Nous introduisons ici la notion de cryptographie distribue base de motsde passe, dans laquelle les joueurs n'ont besoin de retenir que de petitsmots de passe (de faible entropie). Il n'est ici plus possible de publierles clefs publiques associes, car ces dernires permettraient alors deretrouver, partir d'une recherche exhaustive, les mots de passeinitiaux. Dans un tel cadre, la clef prive est donc dfinie implicitementcomme la combinaison des mots de passe de faible entropie dtenus pardiffrents utilisateurs. Sans jamais rvler cette clef prive, lesutilisateurs vont pouvoir calculer et diffuser la clef publique associe.Ils peuvent ensuite effectuer ensemble des oprations clef prive(telles que du dchiffrement) en changeant des messages travers uncanal arbitraire, partir de leurs mots de passe respectifs, sans jamaisdevoir partager leurs mots de passe ou reconstruire la clef.Nous donnons un exemple concret d'un tel protocole, bas sur lechiffrement ElGamal, qui possde deux variantes: la premire, simple etefficace, repose sur l'hypothse Diffie-Hellman dcisionnelle; la secondeutilise des techniques base de couplages et est sre sous l'hypothselinaire dcisionnelle. L'intrt de cette deuxime variante est de segnraliser un certain nombre de cryptosystmes clef publique basssur le logarithme discret, ce qui inclut en particulier le chiffrementlinaire et le chiffrement bas sur l'identit. Ceci permet d'tendrel'IBE de faon distribue, en effectuant la gnration de clef par ungroupe de personnes, chacune d'elle mmorisant une petite portion de laclef matre.Dans ces modles, la totalit des utilisateurs doivent cooprer pourpouvoir retrouver (au moins implicitement) la clef prive et effectuer dudchiffrement. Modifier le protocole de cryptographie distribue base demots de passe pour qu'il devienne " seuil" (c'est--dire quet utilisateurs parmi n suffisent) est encore un problme ouvert.
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    Date:28/01/2010, 14h - 15h
    Room:Amphi Saphir
    Speaker:Yves Guiard (CNRS & Tlcom ParisTech)
    Talk:Sur le lien entre la vitesse et l'imprecision de nos mouvements et sur le rle du facteur d'chelle
    Abstract:Le but de la psychologie exprimentale est d'introduire un peu de rigueurdans le traitement des questions concernant la perception, la motricit etla cognition. Depuis Fechner (1866), la psychophysique s'efforce dequantifier la relation liant nos sensations subjectives aux grandeursphysiques. Il existe une tradition similaire, moins connue mais presqueaussi ancienne, visant identifier l'interdpendance de la vitesse et dela prcision de nos mouvements. On a bien avanc depuis Woodworth (1899),notamment avec la dmonstration de ce qu'on appelle la loi de Fitts (1954):dans le pointage vers une cible, le temps ncessaire l'excution dumouvement varie gnralement comme le logarithme du rapport entre ladistance parcourir et la tolrance de la cible.La loi de Fitts est d'application quasi routinire en interactionhomme-machine, o elle aide les designers d'interfaces optimiser laconfiguration de leurs objets graphiques, cibles du pointage del'utilisateur. Mais cette rgularit empirique n'est valide que sur unegamme d'chelle limite : elle n'est plus d'aucun secours, en particulier,quand il s'agit de modliser des mouvements de trs petite amplitude commeceux d'un doigt sur l'cran d'un montre-bracelet faisant office detlphone. En fait, comme j'essaierai de l'expliquer dans l'expos, il estimpossible de saisir le rle du facteur d'chelle dans le problme dupointage sans mettre en question la dfinition usuelle des variables duproblme.
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    Date:21/01/2010, 14h00 - 15h00
    Room:Amphi Saphir
    Speaker:Philippe Godlewski et Azin Arya (Tlcom ParisTech & SFR)
    Talk:"Radio fingerprinting" for localization of mobile terminals
    Abstract:In the recent years the Location Based Services (LBS) are grabbing theattention of telecommunication actors since they are sources of newservices and new revenues. The main challenge in the LBS domain is thelocalization of the mobile terminals within a certain accuracy. To thisend, several radio positioning techniques have been introduced, one ofwhich is the Location Fingerprinting.Although location fingerprinting has been investigated in some previousworks, there are only few studies that analyze its performance accordingto physical parameters of the underlying environment. Thus, as a firstapproach, we consider an outdoor location fingerprinting system, andwe examine the impact of different physical parameters on the systemperformance. As a second step, we present "clustering techniques"which aim to compress the radio database and hence to reduce the onlinecomputation load of the system. Any compression process may degradethe system performance, so we try to find a clustering technique whichminimizes this degradation, and provides an acceptable level ofpositioning accuracy.
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    Date:21/01/2010, 14h - 15h
    Room:Amphi Saphir
    Speaker:Philippe Godlewski et Rodrigo Soul de Castro (Tlcom ParisTech)
    Talk:Canaux radio cognitifs en diffusion et en contrle MAC pour l'accs dynamique au spectre (DSA)
    Abstract:Actuellement, de nombreuses bandes du spectre hertzien sont assignes des systmes de communications correspondant chacun des typesd'usages bien fixs (tlvision, cellulaire, satellite, WLAN ou PAN,PMR, ...). On parle alors d'allocation (ou d'assignation) fixe despectre (FSA). Un certain nombre d'tudes visent maintenant rendreplus flexible et dynamique l'accs au spectre (DSA, Dynamic ChannelAllocation) des systmes radiomobiles. Ces tudes utilisent desprincipes "radio cognitifs" et considrent souvent une situation avecdes utilisateurs primaires et secondaires.Aprs avoir rappel ce contexte, nous prsentons deux types de canaux(CCCh, cognitive control channel, CPC, cognitive pilot channel) qui, ensuperposition des standards actuels, peuvent faciliter des usages plusflexibles du spectre.
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    Date:17/12/2009, 14h - 15h
    Room:Amphi Saphir
    Speaker:Grard Memmi (Tlcom ParisTech)
    Talk:Sur un problme de couplage
    Abstract:Il s'agit de dcrire plus une dmarche qu'un rsultat. Le problme initial est un problme de design lectronique pos par J. de Sousa : L'acheminement de combinaisons de signaux vers un traceur est trs couteux en terme de nombre de portes lectroniques ncessaires pour remplir cette fonction. Usuellement, on utilisera un ensemble de multiplexeurs. Aprs un effort de formulations du problme nous arrivons une question d'architecture de routage de signaux. Puis il sera ais de passer un problme de graphe extrmal, enfin une question de couplage dans un graphe biparti. On pourra dduire du rsultat principal les grands thormes de couplage tablis dans les annes 50 60. La question suivante qui reste ouverte, porte sur l'originalit du rsultat qui amnera regarder rapidement une question d'architecture de rseaux.
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    Date:10/12/2009, 14h - 15h
    Room:Amphi Jade
    Speaker:Maximilien Gadouleau (Univ. Reims)
    Talk:Codes algbriques pour le codage rseau alatoire
    Abstract:Le codage rseau est une technique moderne, lgante et efficace detransmission de donnes travers un rseau. Il permet aux noeudsintermdiaires d'oprer des combinaisons linaires sur les paquets qu'ilsreoivent avant de les retransmettre. Afin d'augmenter la flexibilit duprotocole, les combinaisons linaires sont choisies au hasard. Cettetechnique, appele codage rseau alatoire, permet d'atteindre le dbitmaximum thorique et d'assurer une grande robustesse face aux changementsde topologie du rseau.Malgr ses nombreux avantages, le codage rseau alatoire est trssensible aux erreurs pour deux raisons. Premirement, les erreurs ont denombreuses causes: pertes de paquets, liens ou noeuds imparfaits,adversaire sur le rseau etc. Deuximement, les combinaisons linaireseffectues dans les noeuds intermdiaires propagent les erreurs traversl'ensemble des paquets. Ainsi, les techniques de codage d'erreursclassiques sont inadaptes au codage rseau alatoire.Dans ce sminaire, nous nous intressons aux classes de codes correcteursd'erreurs proposs cet effet, c'est--dire les codes en mtrique rang etles codes de sous-espaces. Nous tudions particulirement la performancedes codes en mtrique rang contre un adversaire injectant des paquetsmaliceusement sur le rseau.
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    Date:03/12/2009, 14h - 15h
    Room:Amphi Saphir
    Speaker:Marco Cagnazzo (Tlcom ParisTech)
    Talk:Compression for the Network: Scalable and Multiple Description Coding
    Abstract:Traditional video compression techniques have the implicit assumptionsthat the final user characteristics and requirements are known and do notchange with time. Moreover, usually robustness is not taken into accountwhen designing a video coder. This approach is clearly unfit to the videodelivery over computer networks.In order to improve the adaption between the encoder, the network and theusers, a departure from traditional approaches is needed. The basic ideais to split the video representation into sub-streams; in particular onecan have a hierarchical organization of sub-streams or not. In the firstcase, called Scalable Video Coding (SVC), each new sub-stream refines theinformation provided by previous ones, but is useless if these are notreceived. In the second case, called Multiple Description Coding, any setof sub-streams is decodable, but the compression performances aredegraded with respect to SVC.In this talk, after motivating the interest for SVC and MDC, a briefrecall about video coding techniques will be performed, followed by thedescription of main scalability techniques implemented into standards. Inparticular the trade-off between scalability, compression performance andcomplexity will be explored. Some attention will be given to the important"drift problem" for scalable video. Finally, a few words aboutnon-standard scalable and MDC techniques will be given as well.
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    Date:26/11/2009, 14h - 15h
    Room:Amphi Saphir
    Speaker:Dario Rossi (INFRES Telecom Paristech)
    Talk:P2P-TV: State of Art and Application Analysis via Sherlock
    Abstract:After P2P file-sharing and VoIP telephony applications, VoD and live-streaming P2P applications have finally gained a large Internet audience as well. A first part of this talk is therefore devoted to an overview of the current state of art in the field of P2P-TV applications.The reminder of the talk then focuses on the definition a framework for the comparison of P2P applications in general, based on the measurement and analysis of the traffic they generate.In order for the framework to be descriptive for all P2P applications, we first define the observable of interest: such metrics either pertain to different layers of the protocol stack (from network up to the application), or convey cross-layer information (such as the degree of awareness, at overlay layer, of properties characterizing the underlying physical network).The framework is compact (as it allows to represent all the above information at once), general (as is can be extended to consider metrics different from the one reported in this work), and flexible in both space and time (as it allows different levels of spatial aggregation, and also to represent the temporal evolution of the quantities of interest). Based on this framework, we analyze some of the most popular P2P application nowadays, highlighting their main similarities and differences.
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    Date:12/11/2009, 14h - 15h
    Room:Amphi B312
    Speaker:Claude Chaudet
    Talk:Quelques pistes pour accrotre la dure de vie d'un rseau de capteurs
    Abstract:Les rseaux de capteurs sont des rseaux particuliers car, au del des considrations de performance, leur objectif premier est gnralement d'assurer la surveillance (en termes de temprature, de pression, deprsence de polluants, de prsence d'individus,...) d'une zone gographique le plus longtemps possible. En effet, ces rseaux sont composs de nombreux lments de faible capacit individuelle, fonctionnant grce des sources d'nergie limites ou rechargeables un rythme lent. Or, ces capteurs tant a priori les seuls lments dploys, ils doivent assurer le bon fonctionnement du rseau, et notamment la retransmission en mode ad hoc des trames.Dans cet expos, nous commercerons par dtailler ces contraintes particulires et nous reviendrons plus particulirement sur la notion de dure de vie du rseau qui admet de nombreuses dfinitions, lies aux applications. Puis nous exposerons plusieurs travaux relatifs notamment l'accs au mdium, au routage et la combinaison de donnes dans ces rseaux.
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    Date:12/11/2009, 16h30 - 17h30
    Room:Amphi B312
    Speaker:Michel Marot (Telecom SudParis)
    Talk:Quelques lments pour contribuer la problmatique du routage dans les rseaux de capteurs.
    Abstract:Les rseaux de capteurs sont prvus pour tre dploys dans des conditions extrmements varies, ncessitant tantt de petits rseaux, tantt de trs grands rseaux (jusqu' plusieurs milliers). Cela conduit mettre au point des solutions efficaces pour scinder ces rseaux en clusteurs. Dans cette prsentation, nous aborderons d'abord la problmatique de la formation des clusteurs. Dans une premire partie, nous exposerons nos travaux sur la validation d'un algorithme assez connu pour la formation des clusteurs: le MaxMin. Cet algorithme est trs souvent cit mais n'avait jamais t valid.Dans une deuxime partie, nous prsenterons un retour d'expriences menes sur une plate-forme de rseaux de capteurs. Nous montrerons comment ces rseaux souvent bass sur des algorithmes multiniveaux et trs dynamiques conduisent parfois de srieux problmes de stabilit ou des choix de routes inattendus. Nous aborderons le problme des liens assymtriques dans les rseaux de capteurs.
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    Date:29/10/2009, 14h - 15h
    Room:Amphi Saphir
    Speaker:Jnos Krner (Univ. Rome 1 "La Sapienza")
    Talk:Structures of diversity
    Abstract:In information theory, one is mostly interested in the maximum cardinality of a set of strings of a common length n with the property that any two (or more) of the strings from the set differ in some particular manner. This happens because the strings are codewords used to transmit information through a noisy device so that the output sequences are distorted versions of the inputs, yet we need to tell them apart in order to recover, at the receiving end, the information encoded by different input strings.In the more combinatorial zero-error problems, the pairwise difference relation between code strings can be expressed in terms of a graph. The vertices of the graph are the symbols from the input alphabet of the physical channel, and adjacent vertices correspond to symbols which cannot be confused at the receiving end. In 1956 Shannon asked for the determination of the maximum number of strings of length n such that any two of them differ in some coordinate in a pair of adjacent vertices of the graph G. The exponential asymptotics of this number, as n goes to infinity, is the capacity of the graph.From an abstract point of view, a difference relation for strings is a pairwise relation whose main feature is that of being irreflexive. A further characteristic of a difference relation is that if two strings have a projection onto a subset of their coordinates that are in this relation as strings, then already this guarantees that the pair of strings are in the same relation. We will refer to this property as local verifiability. It is easy to see how any difference relation leads to a concept of capacity.We will give several examples of problems in extremal combinatorics that we can solve within this framework, using information theoretic intuition and methods.
    Biography:Jnos Krner was born in Budapest, Hungary, on November 30, 1946. He received the degree in mathematics at the Etvs University, Budapest, Hungary, in 1970.After graduation, he joined the Mathematical Institute of the Hungarian Academy of Sciences, Budapest, where he worked until he left Hungary, in 1989. From 1981 to 1983, he was on leave at AT&T Bell Laboratories, Murray Hill, NJ. At present, he is a Professor in the Department of Computer Science at the University of Rome 1 "La Sapienza", Rome, Italy.With Imre Csiszr, he is the author of the book "Information Theory: Coding Theorems for Discrete Memoryless Systems". His main research interests are in combinatorics, information theory, and their interplay. Prof. Krner served as Associate Editor for Shannon Theory for IEEE TRANSACTIONS ON INFORMATION THEORY from 1983 to 1986.
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    Date:22/10/2009, 14h - 15h
    Room:Amphi Saphir
    Speaker:Aruna Jayasuriya (ITR, Univ. South Australia, Adelaide)
    Talk:Supporting QoS for Realtime Applications in Wireless Infrastructure Networks
    Abstract:In recent years, there has been a rapid growth in deployment and usage of realtime network applications, such as Voice-over-IP, video calls/video conferencing, live network seminars, and networked gaming. At the same time, wireless networking technologies have become increasingly popular with a wide array of devices such as laptop computers, Personal Digital Assistants (PDAs), and cellular phones being sold with built-in WiFi and WiMAX interfaces. For realtime applications to be popular over wireless networks, simple, robust and effective QoS mechanisms suited for a variety of heterogeneous wireless networks must be devised.To provide guaranteed QoS, an access network should limit load using an admission control algorithm. In this research, we propose a method to provide effective admission control for variable bit rate realtime flows, based on the Central Limit Theorem. Our objective is to estimate the percentage of packets that will be delayed beyond a predefined delay threshold, based on the mean and variance of all the flows in the system. Any flow that will increase the percentage of delayed packets beyond an acceptable threshold can then be rejected. Using simulations we have shown that the proposed method provides a very effective control of the total system load, guaranteeing the QoS for a set of accepted flows with negligible reductions in the system throughput.We also propose a method to determine the delay-dependent "value" of a packet based on the QoS requirements of the flow. Using this value in scheduling is shown to increase the number of packets sent before a predetermined deadline. We propose a measure of fairness in scheduling that is calculated according to how well each flow's QoS requirements are met. We then introduce a novel scheduling paradigm, Delay Loss Controlled-Earliest Deadline First (DLC-EDF), which is shown to provide better QoS for all flows compared to other scheduling mechanisms studied.
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    Date:15/10/2009, 14h - 15h
    Room:Amphi Saphir
    Speaker:Jacques Sakarovitch (CNRS & Tlcom ParisTech)
    Talk:A propos des automates avec multiplicit, sur les langages rationnels de mme fonction gnratrice
    Abstract:La plupart des modles de calculs qu'ils soient drivs de la machine de Turing (automates finis, pile, compteurs, etc.) ou non (systmes de rcriture, rseaux de Petri, etc.) ont pour objet de distinguer parmi les squences de symboles, suites d'actions, etc. celles qui sont acceptes, ou correctes, ou valides, de celles qui ne le sont pas. Les automates avec multiplicit (weighted automata en anglais) permettent d'associer chaque squence un coefficient, lment de l'univers qu'on aura choisi pour modliser le phnomne tudi, et qui donne plus d'informations sur la squence qu'un simple 0-1. Cela ouvre le champ l'tude de systmes quantitatifs.Les possibilits de modlisation sont multiplies l'infini, mais l'tude de ces automates avec multiplicit est naturellement plus complexe. Ces dernires annes, j'ai dvelopp avec mes tudiants des techniques dites structurelles qui permettent d'analyser au del d'un rsultat les calculs qui mnent ce rsultat. Dans cet expos, j'en prsenterai un aperu avec la preuve du rsultat suivant:Si deux langages rationnels (ie accepts par un automate fini) L et K ont la mme fonction gnratrice, c'est--dire que pour chaque entier n il y a le mme nombre de mots de longueur n dans L et dans K, il existe un transducteur fini lettre--lettre (un automate fini dont toutes les transitions sont tiquetes par un couple de lettres) qui ralise une bijection entre L et K.Cet nonc, qui rsout une conjecture obscure de la thorie confidentielle des structures automatiques, est une consquence d'un raffinement de la dcidabilit de l'quivalence de deux automates finis avec multiplicit dans N et en l'occurrence le prtexte sa prsentation: deux N-automates sont quivalents si, et seulement si, ils sont conjugus, par des matrices coefficients dans N, un mme troisime et de l'interprtation de la conjugaison comme une succession de revtements et de co-revtements raliss par fusion et clatement des tats. Tout ceci est tir d'un travail en collaboration avec Marie-Pierre Bal et Sylvain Lombardy, de l'universit Paris-Est, Marne-la-Valle.
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    Date:24/07/2009, 14h - 15h
    Room:Amphi Rubis
    Speaker:Pr. Erol Gelenbe, Imperial College London
    Talk:Steps toward self-aware networks
    Abstract:This talk focuses on how network software adapts to user needs, load variations and failures to provide reliable communications in largely unknown networks. For more details, see Steps toward self-aware networks , in Communications of the ACM, Volume 52, Issue 7, July 2009
    Biography:Erol Gelenbe (FACM, FIEEE, FIEE) holds the Dennis Gabor Chair at Imperial College. He has made decisive contributions to product form networks by inventing G-networks (Gelenbe-Networks) with totally new types of negative customers, triggers, and resets and which are characterised by non-linear traffic equations. He has made seminal contributions to random access communications, the optimisation of reliability in database systems, the design of adaptive QoS-aware packet networks, diffusion models in performance analysis, and the performance of link control protocols.
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    Date:28/05/2009, 14h - 15h
    Room:Amphi Saphir
    Speaker:Minh Anh Tran, PostDoc at ENST
    Talk:Thorie des jeux pour la modlisation des terminaux mobiles multi-homs
    Abstract:Chaque terminal est quip aujourd'hui de plusieurs interfaces de technologies radio diffrentes. Il devient possible d'utiliser simultanment les diffrentes interfaces, et non seulement de basculer d'un rseau un autre. Les terminaux sont en concurrence entre eux pour l'accs aux ressources de diffrents rseaux, chacun cherchant satisfaire un optimal local (stratgie dite goste). Cela relve un problme d'optimisation multi-objectif qui peut tre tudi en utilisant la thorie des jeux. Dans notre modle, les terminaux tournent plusieurs applications en mme temps et peuvent associer chaque application une interface spcifique afin de maximiser leur fonction d'utilit. Nous montrons qu'avec un mcanisme de prix appropri, le systme tend vers des quilibres qui ralisent un optimal global. Enfin, nous prsentons quelques perspectives de ce travail.
    Biography:Minh Anh Tran est sorti de l'Ecole Polytechnique en 2004. Il a fait ensuite une thse en Informatique et Rseaux dans l'quipe TREC de ENS Ulm. L'anne dernire, il a fait un postdoc Stanford, et maintenant, il travaille avec Nadia Boukhatem dans le projet 3MING.
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    Date:16/04/2009, 14h - 15h
    Room:Amphi Grenat
    Speaker:Guillaume Valadon, PhD
    Talk:Mesure et analyse des reseaux
    Abstract:Guillaume Valadon est post-doctorant au sein de l'quipe Complex Networks ( http://complexnetworks.fr/ ) au LIP6. Durant sa thse, effectue entre le Japon et la France, il a travaill sur la mobilit au sens large; notamment MANET, Mobile IPv6, ainsi que la scurit de ces protocoles (voir http://valadon.complexnetworks.fr/ ).Lors de cette prsentation, il abordera deux amliorations de Mobile IPv6, l'une pratique l'autre thorique. Ces deux approches complmentaires compatibles avec l'infrastructure actuelle de l'Internet, permettent de grer la mobilit de faon transparente la fois pour le rseau et les priphriques fixes.Dans une seconde partie, il discutera de travaux en cours portant sur la dynamique de la topologie d'Internet, et l'analyse du trafic d'un serveur eDonkey. Plus particulirement, il sera abord la mesure de la topologie de l'Internet depuis une source vers un ensemble de destinations ainsi que l'volution de cette topologie au cours du temps. En ce qui concerne eDonkey, des rsultats prliminaires visant identifier les changes de fichiers pdophiles seront discuts.
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    Date:12/02/2009, 14h - 15h
    Room:Amphi Saphir
    Speaker:Pr. Marceau Coupechoux, ENST
    Talk:Analytical Evaluation of Various Frequency Reuse Schemes in OFDMA Networks
    Abstract:In this presentation, we present an analytical solution to carry out performance analysis of various frequency reuse schemes in an OFDMA based cellular network (like WiMAX or LTE networks). We study the performance in downlink in terms of signal to interference (SIR) ratio and cellular capacity. Analytical models are proposed for integer frequency reuse (IFR), fractional frequency reuse (FFR) and two level power control (TLPC) schemes. These models are based on a fluid model originally proposed for CDMA networks. The modeling key of this approach is to consider the discrete base stations entities as a continuum. To validate our approach, Monte Carlo simulations are carried out. Results of validation study show that results obtained through our analytical method are in conformity with those obtained through simulations. However, compared to time consuming simulations, our model is very time efficient. We also present a comparison between above three frequency reuse schemes.
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    Date:29/01/2009, 14h - 15h
    Room:Amphi B312
    Speaker:Pr. Pascal Urien, TELECOM ParisTech, founder of EtherTrust
    Talk:Des cartes puce pour l'Internet: "Are you serious". Petite histoire d'EtherTrust, spin-off de Tlcom ParisTech.
    Abstract:Internet rvolutionne chaque jour un peu plus l'informatique distribue et les applications multimdia. La toile est un acteur fondamental de l'conomie mondiale, dans un environnent mergent ou les technologies des rseaux radio de quatrime gnration (4G, WiMAX) amplifient le paradigme du always on. Dans ce contexte la scurit est souvent cite comme un pr-requis et un enjeu (financier) majeur. Cependant la ralit semble tout autre: bien que la cryptographie ait produite des algorithmes solides et que des preuves formelles existent sur des protocoles tels que SSL, l'internaute utilisent de (trop) nombreux mots de passe et surfe l'aide d'ordinateurs dmunis de scurit physique. Par ailleurs une socit connecte en permanence, amplifie l'effet big brother, c'est--dire la contradiction entre le respect de la vie prive (privacy) et la traabilit induite par les technologies radio enfouies. Dans cet expos nous prsenterons quelques rsultats significatifs ainsi que le modle de scurit que nous avons bti, reposant sur une pile trois niveaux: scurit des accs, des VPN, et des applications. L'originalit de cette approche est de s'appuyer sur une architecture collaborative entre des terminaux ou des serveurs informatiques muni de grande puissance de traitement mais non scuriss, et des modules de scurit (des cartes puce) garantissant une scurit forte mais offrant de faibles capacits de calcul. C'est une recherche pragmatique, nous collaborons troitement avec l'industrie mais galement avec les organismes de normalisation tels que l'IETF. EtherTrust, est une spin-off (fonde en 2007) issue de ces travaux, qui a pour objectif de commercialiser des solutions, des matriels et des logiciels ddis la scurit d'un monde convergent tout IP. Sa principale originalit est de s'appuyer sur une technologie carte puce, dont les principaux acteurs industriels sont Europens et plus particulirement Franais.
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    Date:08/12/2008, 14h - 15h
    Room:Amphi Jade
    Speaker:Pr. Dario Rossi, Telecom ParisTech
    Talk:Stochastic Packet Inspection for Automated Traffic Classification
    Abstract:This talk focuses on KISS, a new addition to the well populated and flavored world of Internet classification engines. Motivated by the expected raise of UDP traffic volume, which stems from the momentum of P2P streaming applications,we propose a novel statistical payload-based classification framework, targeted to UDP traffic. Statistical signatures are automatically inferred from training data, by the means of a Chi-Square like test, which extracts the protocol "syntax", but ignores the protocol semantic and synchronization rules. The signatures feed a decision engine based on Support Vector Machines. KISS is very efficient, and its signatures are intrinsically robust to packet sampling, reordering, and flow asymmetry, so that is can be used on almost any network. KISS is tested in different scenarios, considering both data, VoIP, and traditional P2P Internet applications. Results are astonishing. The average True Positive percentage exceeds 99%, and than 0.05% of False positives are raised. But KISS is also proved to provide almost perfect results when facing new P2P streaming applications, such as Joost, PPLive, SopCast and TVants. Finally, we present how KISS can be extented to the TCP case and present preliminary results.
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    Date:03/11/2008, 16h00-17h00
    Room:Amphi Saphir
    Speaker:Pr. Tamer BASAR, University of Illinois at Urbana-Champaign
    Talk:Optimum Active Pricing for Communication Networks
    Abstract:Abstract: The talk will introduce a class of hierarchical games that arises in pricing of services in communication networks with a monopolistic service provider and a large population of users of different types. The probability distribution on different user types is common/public information, but the precise type of a specific user is not necessarily known to all parties. As such the game falls in the class of games with incomplete information, and in our specific case what we have is a problem of mechanism design within an uncertain environment and with asymmetric information. The service provider is a revenue maximizer, with his instrument being the prices charged (for bandwidth) as a function of the information available to him. The individual users are utility maximizers, with bandwidth usage being their decision variable. The congestion cost in their utility functions creates a coupling between different usersu2019 objective functions, which leads to a non-cooperative game at the lower (users) level for which we adopt Nash or Bayesian equilibrium. Solutions to these problems (at both the lower and the upper levels) entail non-standard multi-level optimization problems. Indirect approaches to these optimization problems will be presented, and some asymptotics for large agent-population models will be discussed. (This is based on joint work with Hongxia Shen.)
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    Date:03/11/2008, 14h30-15h30
    Room:Amphi Saphir
    Speaker:Pr. Jean-Pierre HUBAUX, Ecole Polytechnique de Lausanne (EPFL)
    Talk:Game Theory and Wireless Security
    Abstract:Securing wireless networks is notoriously a huge challenge. In this talk, we will first describe current trends in wireless technology and upcoming wireless networks, such as sensor, vehicular, mesh, and RFID networks. We will then address their vulnerabilities and the existing or envisioned protection techniques. We will then consider the specific example of ephemeral networks, namely networks in which the interactions between nodes are short-lived, typically due to their mobility. We will focus on the fundamental security operation of revocation in such networks. We will show how game theory can be used to model the different possible revocation strategies of the nodes and discuss the implications of this model on the protocol design.
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    YEAR = 2014 WHERE = LINCS, Salle du Conseil WHEN = AUTHOR = Ghida Ibrahim (Orange) AUTHOR_URL = HOWPUBLISHED = TITLE = On the Federation of CDN providers ABSTRACT = Content Distribution Services are evolving fast in various directions. One of them is the collaboration of Content Delivery Network (CDN) providers with different capacities, footprints and cost models. In this talk, we focus on one specific form of collaboration that is the federation of CDNs, referring to a number of CDN providers putting together their assets and acting as a single entity with regards to content providers. We introduce a technical solution based on a centralized architecture that allows taking static decisions of federation establishment and provisioning and dynamic decisions of federation control. Static decision making is enabled through an optimization model that we apply to concrete use cases of federation. We demonstrate that, in case of high market demand, CDN providers always have an interest in federating. In particular, some CDN providers can double their economic gains through federating. In the context of federation dynamic control, we focus on the control of peak events within a federation of CDNs and we introduce different control frameworks at this level. We conduct trace-driven simulations in order to assess different frameworks. We demonstrate that, when a joint approach for events control is adopted within a federation of CDNs, the federation is better resilient to peak events. This translates into a higher hit ratio of the federation and a better video resolution witnessed by end users. BIOGRAPHY =