The ForMoSA Approach to Qualitative and Quantitative Model-Based Safety Analysis

Abstract

This chapter presents ForMoSA (FORmal MOdels and Safety Analysis), an integrated approach for the safety assessment of safety-critical embedded systems. The approach brings together the best of engineering practice, formal methods, and mathematics: traditional safety analysis, temporal logics and verification, as well as statistics and optimization. These three orthogonal techniques cover three different aspects of safety: fault tolerance, functional correctness, and quantitative analysis. The ForMoSA approach combines these techniques to assess system safety in a structured and formal way. Furthermore, the tight combination of methods from different analysis domains results in mutual benefits. The combined approach yields results which cannot be produced by any single technique on its own. The methodology was applied to several case studies from different industrial domains. One of them is an autonomous control of level crossings using radio-based communication, which is used in this chapter to describe the individual steps of the ForMoSA methodology.