Automatic Generation of Stateübased Dependability Models: from Availability to Safety

This article describes conceptual issues of the tool SafeME (The Safety Modeling Environment). The tool allows for modeling a safetyücritical, faultütolerant 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 interücomponent dependencies, like failures with a common cause and failure propagation can be included. For numerical evaluation, the model is transformed into a semantically equal stateübased model. As an illustrative example, the paper contains a SafeME model of a faultütolerant temperature control system and shows how this model is converted into a stochastic Petri net.