Safety critical systems require rising dependability due to increasing autonomy. Fault-tolerance is necessary, but failures may cause system resources to become insufficient to provide all intended functional features. We introduce an approach to formally analyze failure scenarios in mixed criticality systems, combined with the synthesis of valid deployments of software to hardware, incorporating adequate redundancy to address mixed reliability. Based on a formal system model, we provide a structural analysis of necessary degradations and failovers in failure scenarios, while ensuring the fulfillment of fail-operational requirements.
Stichworte: Fault Tolerance, Graceful Degradation, Fail-Operational, Dependability, Reliability, Mixed Criticality, Safety, Deployment, Redundancy, Synthesis, Automotive, Formal Methods, Model-based Systems Engineering, MbSE