Validating Formal Verification using Safety Analysis Techniques

The increased interest in the use of automated safety analysis is supported by the claim that manual safety analysis based on traditional techniques is error–prone, costly and not necessarily complete. It is also claimed that traditional techniques are not able to deal with the inherent complexities of software intensive systems. However, we show in this paper that a transition (from manual to automatic approaches) in the assessment process and technologies is accompanied by an inherent risk of obtaining false confidence, unless safeguards are provided. The safeguard presented in this paper integrates traditional deductive and inductive analysis techniques with model checking, a form of formal verification. The aim is to provide the safety analyst with a rigourous approach for the validation of formal models. The feasibility of the overall approach is illustrated in terms of a case study.