Sequence Diagrams

Learning Sequence Diagrams

Sequence Diagrams intend to represent one possible execution trace of the system.

1. Open the slides on Modeling in SysML.


2. Watch the video on Sequence Diagrams.

Practising with Sequence Diagrams

1. Open the slides on Exercises.


2. Read the specification of the Railroad crossing system.


3. Make three sequence diagrams of this system: a norminal (or normal) execution trace, an abnormal execution trace, and an error trace. By "abnormal", I mean a trace that is not likely to occur frequently. For an error trace, I mean showing which decisions the system takes when an error occurs in the system. It could be an error in a sensor or an actuator, or an error of the software itself. Again, you can make your model with TTool, or on paper.


4. Auto-correct your diagram, as explained for requirements. Are your execution traces possible with regards to the activity diagrams you have captured before? Obvisouly, at least your normal trace MUST be included into the possible traces of the activity diagram.



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.