Modeling and automatic failure analysis of safety-critical systems using extended safecharts

Abstract

With the rapid progress in science and technology, we find ubiquitous use of safety-critical systems in avionics, consumer electronics, and medical instruments. In such systems, unintentional design faults might result in injury or even death to human beings. To avoid such mishaps, we need to verify safetycritical systems thoroughly, where formal verification techniques such as model checking play a very promising role. Currently, there is practically no automatic technique in formal verification used to formally model system faults and repairs. This work contributes in proposing an extension to the Safecharts model, with which faults and repairs can be easily modeled. Moreover, these Safecharts can be directly transformed into semantically equivalent Extended Timed Automata models for model checking. That is, after these models were integrated into a model checker, such as our previously proposed State Graph Manipulators (SGM) model checker, we can verify safety-critical systems. An application example is run to show the feasibility and benefits of the proposed model-driven verification method for safety-critical systems. As observed, the checking results, such as witnesses of property specifications representing hazards, provide more concrete and useful failure analysis information than the conventional Fault Tree Analysis (FTA). © Springer-Verlag Berlin Heidelberg 2007.