Certified Embedding of B Models in an Integrated Verification Framework

Abstract

To check the correctness of heterogeneous models of a complex critical system is challenging to meet the certification standard. Such guarantee can be provided by embedding the heterogeneous models into an integrated modelling framework. This work is proposed in the B-PERFect project of RATP (Parisian Public Transport Operator and Maintainer), it aims to apply formal verification using the PERF approach on the integrated safety-critical software related to railway domain expressed in a single modelling language: HLL. This paper presents a certified translation from B formal language to HLL. The proposed approach uses HOL as a unified logical framework to describe the formal semantics and to formalize the translation relation of both languages. The developed Isabelle/HOL models are proved in order to guarantee the correctness of our translation process. Moreover, we have also used weak-bisimulation relation to check the correctness of translation steps. The overall approach is illustrated through a case study issued from a railway software system: onboard localization function. Furthermore, it discusses the integrated verification at system level.