Designing a persistent online strategy game - Department of ...

22 Chapter 3. Requirements engineering with non-functional requirements
of different importance, in the same way as the interdependencies discussed earlier. An
example of such a correlation catalogue is shown in table 3.2. It presents the correlation
between a few NFR softgoals and operationalizing softgoals where the operationalizing
softgoals are presented on the top of the table and the NFR softgoals are represented to
the left.
Table 3.2: Correlation catalogue (adapted from Chung et al. [8]).
Non-functional
requirements
softgoal
Accuracy[Info]
Compressed-
Format-
[Info]
Confidentiality[Info]
HELPS
ResponseTime[Info] HURTS HURTS
Space[Info]
HELPS
Operationalizing softgoal
Validation- Flexible-
[Info] User-
Interface-
[Employee,
Info]
HURTS
WHEN
[condition]
Perform-
First[Info]
HELPS
As seen in table 3.2 there can be empty cells in the catalogues, this simply represent
an undefined correlation. It is also possible to have conditions in the correlation rules,
these are represented by a “WHEN [condition]” clause.
3.4 Eliciting requirements
To define the requirements for a system it is important to gather initial information about
the system one is about to design. The information gathered can then be used in different
methods and frameworks, such as the Non-Functional Framework described earlier, to
further define and specify the requirements. The need to gather more information during
the process might of course also arise. This is a natural part of the design process.
There are several techniques for finding, or gathering, information about a system. The
most basic one is perhaps introspection, where the designer simply tries to imagine what
a system has to accomplish and in what way it has to do it [23]. This might actually
give quite a lot of information, but of course has its drawbacks since the designer does
not have the same idea of a system that the user might have. It can differ in many ways,
experience, skill, goals and so on. There are therefore several data-gathering techniques
that can be used to find information about a system. The actual amount of techniques
is hard to say, but most of them build on the following basic techniques [52]:
– Questionnaires
– Interviews