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18).
284 CHAPTER 5 Systems Engineering Profi le ??”SYSMOD
The use cases of a system can be subject to a domain-logical sequence. This
means, e.g., that use case A cannot be executed before use case B was executed.
This is implicitly formulated by defi ning pre- and postconditions for the use cases.
The postcondition of use case B is part of the precondition of use case A .
If you want to model this explicitly, the system process describes the sequence
of selected use cases. It is itself a stereotyped use case that includes the selected
use cases via the include relationship, and it describes the sequence in an activity
that also uses the ?«systemProcess?» stereotype.
To distinguish the system process clearly from regular use cases, it has its own
notation. It is the most widely used process symbol ( Figure 5.19 ). We have used
system processes in Section 2.4.3 in our approach.
bdd [package] SYSMOD profile [system process]
?«metaclass?»
UML4SysML::UseCase
?«stereotype?»
System process
?«metaclass?»
UML4SysML::Activity
FIGURE 5-18
The stereotype for system processes.


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