Automatic Generation of State-based Dependability Models: from Availability to Safety

Abstract:
This article describes conceptual issues of the tool SafeME (The Safety Modeling Environment). The tool allows for modeling a safety-critical, fault-tolerant system. Several undiserable events like shutdown, accident, unavailability can be defined and are analyzed by within same model. Furthermore, interrelations between these events can be defined. For instance, it is possible to define that no accident can occur after an emergency shutdown. In addition, different kind of inter-component dependencies, like failures with a common cause and failure propagation can be included. For numerical evaluation, the model is transformed into a semantically equal state-based model. As an illustrative example, the paper contains a SafeME model of a fault-tolerant temperature control system and shows how this model is converted into a stochastic Petri net.