Quantitative model-based safety analysis: a case study

Abstract

The rising complexity of many safety-critical systems necessitates new analysis methods. Model-based safety analysis approaches aim at finding critical failure combinations by analysis of models of the whole system (i.e. software, hardware, and failure modes). The big advantage of these methods compared to traditional approaches is that the results are of very high significance. Until now, model-based approaches have only to a limited extent been applied to answer quantitative questions in safety analysis. Model-based approaches in this context are often limited to analysis of specific failure propagation models. They do not include system dynamics and behavior. A consequence is, that the methods are very error-prone because of wrong assumptions. New achievements in the domain of (probabilistic) model-checking now allow for overcoming this problem. This paper illustrates how such an approach for quantitative model-based safety analysis is used to model and analyze a real-world case study from the railway domain.