Use Cases

Use Case Diagrams

Use Case Diagrams intend to represent which elements are part of the system you will design, and which elements are outside of the system to design, i.e. the environment of the system. What you put "inside" the boundary of the system is what you promise to design. What you put outside should be provided by an external entity (e.g. another team, another company).

1. Open the slides on Modeling in SysML.


2. Watch the video on Use Case Diagrams.


3. Find the latest SysML specification in the OMG website. Download this specification.


• Read the "Overview" on "Use Cases". This presentation should give another point of view with regards to my lecture.


• Two Use Case Diagrams are given in Figures D5 and D6 of the SysML standard. What do you think of these diagrams?

Practising with Use Case Diagrams

1. Open the slides on Exercises.


2. Read the specification of the Railroad crossing system.


3. Make your own use case diagram of this system. Try to have nore more than 10 use cases. Again, you can make your model with TTool, or on paper.


4. Auto-correct your diagram, as explained for requirements. Are there important use cases that are not in your diagram? Also, guidelines for use case diagrams are repeated in the exam page, "Advices and common mistakes" section. Do you repect these guidelines?


5. Once you are satisfied with your model, exchange your diagram with the diagram of another student of the course.


6. You may also want to have the opinion of your teacher. Do ask by zoom for remarks.