Deriving state-based behavior in systems engineering

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Systems engineering state chart diagrams show the behavior of a use case block.

About this task

You can create a systems engineering state chart diagram to show the state based behavior of a use case block. This behavior captures all known flows found in the black box activity diagram and corresponding sequence diagrams. In this task, you add the necessary components to the black box activity and statechart diagrams. Then you create and execute the statechart diagram. This task shows high level steps for the procedure.
Roles:
  • Systems engineers
Artifacts:
  • Use case black box activity diagram
  • Use case black box sequence diagrams

Procedure

  1. Identify wait states. Perform these sub steps:
    1. In the use case black box activity diagram, note all actions that use IN actor pins.
    2. In the use case black box sequence diagram, note the messages that trigger the actions found in step 1a.
    3. In the statechart diagram, create a wait state that describes the system status for each action found in step 1a.
  2. In the use case black box activity diagram, identify all actions with multiple outgoing completions that use guard conditions.
  3. In the statechart diagram, complete these sub steps:
    1. Create an action state for each action found in step 2.
    2. Allocate the corresponding action to each state.
  4. Connect each state. In the state chart diagram, perform these sub steps:
    1. Add a default connector that identifies the initial state.
    2. Identify transactions, triggering events, and associated actions.
      You can identify these elements by examining each use case sequence diagram.
  5. Execute the statechart.

What to do next

Perform hierarchical structuring of the statechart.
Tip: Identify states that can be aggregated. You can use grouping criteria that includes categories such as "system modes", "system phrases", or "reuse of system patterns. When you have completed this structure, re-execute the statechart.