It is a stereotype ?«extendedRequirement?» as a specialization of the SysML
stereotype ?«requirement?» (Figure 5.5).
5.3 Extended Requirement
276 CHAPTER 5 Systems Engineering Profi le ??”SYSMOD
?– Risks : What risks hide behind a requirement? For example, are there doubts
whether the technical realization is at all possible, or whether the requirement
will encourage political forces that might work against the project?
You can group a large number of possible requirements in categories. The
FURPS model distinguishes between fi ve categories: F unctionality, U sability,
R eliability, P erformance, and S upportability [19]. It is normally a good idea to defi ne
your own stereotypes for these requirement categories. SysML does not provide any
specifi cation since the categories are all very project-specifi c and cannot be defi ned
for general purposes. Figure 5.6 shows the categories of the SYSMOD profi le.
5.4 Essential Activity
bdd [package] SYSMOD profile [extendedRequirement]
?«stereotype?»
OMGSysML::Requirement
priority:PriorityKind
obligation:ObligationKind
stability:StabilityKind
type:ReqTypeKind
risks:String[*]
?«stereotype?»
Extended requirement
high
medium
low
?«enumeration?»
PriorityKind
obligatory
nonobligatory
?«enumeration?»
ObligationKind
stable
instable
?«enumeration?»
StabilityKind
user
system
?«enumeration?»
ReqTypeKind
FIGURE 5-5
The ?«extendedRequirement?» stereotype.
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