Page 187 - Software and Systems Requirements Engineering in Practice

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C C h a p t e r 5 : Q Q u a l i t y A t t r i b u t e R e q u i r e m e n t s 153 153
Goal Modeling of Factors, Issues, and Strategies
Goal modeling is a useful way to describe the relationships among
factors, issues, and strategies. Each factor represents the goal of
developing a product compatible with that factor. Each issue represents
a derived goal, namely to develop a product that satisfices a particular
combination of factor-goals, even though they appear to conflict with
each other. Each strategy, if adopted, represents a design decision that
contributes to satisficing some issue-goals and some factor-goals and
detracts from satisficing others. Finally, the engineering requirements
sponsored by the architecture team have satisficing relationships to
the chosen strategies. Figure 5.4 uses goal modeling to depict
relationships among factors, issues, and strategies.
Managing Factors, Issues, and Strategies
As with functional requirements, it is important to have a definite
procedure for managing factors, issues, and strategies. We have
already mentioned that it is useful to put them in a requirements
catalog, if a suitable tool is already in use in the organization. However,
unlike conventional requirements management, the whole purpose
of Global Analysis is to identify a small number of high-priority issues
and corresponding strategies that shape the architecture. If you don’t
manage toward this goal, global analysis can grow into a very large,
Use ASP – – Use Current Staff,
Technology Who Don’t Yet Factors
Know ASP
+ + + +
Use ASP with
Current Staff Issues
+ + +
Hire a ASP Localize Use Hold ASP
Expert of ASP Classes Strategies
FIGURE 5.4 Goal modeling