Bridging the gap between KAOS requirements models and B specifications

Employing formal methods for complex systems specification is steadily growing from year to year. Whereas the formal specification process from abstraction to implementation via refinement is well understood, the traceability between initial user requirements (requirements analysis) and the corresponding formal specification is still unsatisfying and ambiguous. In fact, there is little research on reconciling the requirements phase with the formal specification phase. Consequently, the gap between the requirements phase and the formal specification phase continues to grow larger and the reconciliation seems more and more difficult and complicated. Our objective is to combine these two phases by using KAOS and the B method. KAOS is a goal-oriented methodology for requirements engineering enabling analysis to build requirements models and to derive requirements documents. B is a model-based formal method supported by tools and that allows the design of systems, from specification to implementation. For that purpose, we propose to derive the architecture of the B specification from the KAOS goal model. This makes traceability between KAOS requirements and B models more explicit.