A formal basis for consistency, evolution and rationale management in requirements engineering

This paper presents a formal framework that addresses the twin problems of inconsistencies in requirements specifications and requirements evolution. It presents techniques (building on results from the areas of default reasoning and belief revision) for identifying maximal consistent subsets of a specification rendered inconsistent by a change step, with provision for retaining requirements that would be otherwise discarded, in anticipation of their future reuse. The paper identifies the need for consistent application of requirements rationale and provides support for this in the framework. While the problem of requirements evolution is intractable in the general case, tractable special cases exist within the framework. The paper also provides pointers to designing tools based on this framework.