Failure Behavior Analysis for Reliable Distributed Embedded Systems

Failure behavior analysis is a very important phase in developing large distributed embedded systems with weak safety requirements which do graceful degradation in case of failures. Today, the analysis will usually be done by standard methods like FTA and FMEA considering the existence of faults, only. Gradations of errors are not regarded, although this is a very coarse system behavior approximation. In contrast to that, our advanced failure behavior analysis yields more sophisticated and graded results. We obtain comprehensive results by assigning a quality description to all the information in a system and extending the pure information flow to an information quality flow, that models system failure behavior, too. We model this information quality flow by object-oriented hierarchical petri nets. Large parts of these nets can automatically be generated from the existing behavioral system structure. A net simulator enables us to perform all the sophisticated analyses we need to examine the failure behavior.