Page 191 - 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 157 157
• Define rules based on values of field device properties that
trigger reactions.
• Issue commands to set values of field device properties.
• For life-critical situations, trigger alarms notifying appropriate
users.
Taking this approach would allow the company to reduce internal
development costs, since several existing applications will be replaced
with the new system. The company could also achieve market expansion
by entering new and emerging geographic markets and opening new
sales channels in the form of value-added resellers (VARs).
It is clear that some of these business goals will have a significant
impact on the development of the building automation system; e.g.,
hardware devices from many different manufacturers would need to
be supported; consideration would have to be made to take the
language, culture, and regulations of different markets into account;
tradeoffs would need to be made and risks assessed to determine the
extent to which the product should support these goals; and depending
on the company’s comfort level with the tradeoffs and risks, these
goals might need to be refined, e.g., scaling back on the intended
markets. Therefore, it is highly relevant to use these as a starting
point for deriving not only the features that the building automation
system must support but also the forces (architectural drivers) that
will shape its architecture. Table 5.4 shows these business goals and
their refinement.
Features That Define the Product
Business goals play a significant role in defining the critical features
that a product must support. For instance, integration implies that
the features of existing applications to be integrated must be
Business Goal Goal Refinement
Reduce internal Integrate existing applications into a single unified
development costs software package: the building automation system
Expand by entering Support international languages
new and emerging Comply with regulations impacting life-critical
geographic markets
systems, such as fire alarms, to operate within
specific latency constraints
Open new sales Support hardware devices from different
channels in the manufacturers
form of value-added Support conversions of nonstandard units used by
resellers (VARs)
the different hardware devices
TABLE 5.4 Business Goals for the Example Building Automation System