Detecting Consistencies and Inconsistencies of Pattern-Based Functional Requirements

The formal specification of functional requirements can often lead to inconsistency as well as unintended specification, especially in the early stages within the development process. In this paper, we present a formal model checking approach which tackles both of these problems and is also applicable during the requirements elicitation phase, in which no component model is available. The presented notion of consistency ensures the existence of at least one possible run of the system, which satisfies all requirements. To avoid trivial execution traces, the "intended" functional behavior of the requirements is triggered. The analysis is performed using model checking. More specifically, to reduce the overall analysis effort, we apply a bounded model checking scheme. If the set of requirements is inconsistent the method also identifies a maximal sub-set of consistent requirements. Alternatively, a minimal inconsistent sub-set can be computed. The approach is demonstrated on a railway crossing example using the BTC Embedded Specifier and the iSAT model checker