Analogical reuse of requirements frameworks

Reusing similar requirements fragments is one of the most promising ways to reduce the elaboration time and increase the requirements' quality. This paper investigates the application of analogical reasoning techniques to complete partial requirement specifications. A case base is assumed to be available; it contains requirements frameworks involving goals, constraints, objects, actions and agents from systems which have already been specified. We show how a rich requirements meta-model, coupled with an expressive formal assertion language, may increase the effectiveness of analogical reuse. An acquisition problem is first specified by a requirements engineer as a query formulated in the vocabulary of the specification fragments built so far. Source cases and partial mappings are found by query generalization followed by a search through the case base. Once analogies have been confirmed, mappings are completed by the use of relevance rules that distinguish, in the formal assertions, what is relevant to the analogy from what is irrelevant. The best analogies are then selected and extended in such a way that the logical properties of the answers to the query may be verified, thus increasing confidence in the analogy. The approach is illustrated by analogical acquisition of specifications of a meeting scheduler in the KAOS goal-oriented specification language.