Synthesizing Failure Detection, Isolation, and Recovery Strategies from Nondeterministic Dynamic Fault Trees

Redundancy concepts are an integral part of the design of space systems. Deciding when to activate which redundancy and which component should be replaced can be a difficult task. In this paper, a model of nondeterministic dynamic fault trees is presented. It is shown how appropriate recovery strategies can be synthesized from them. This is achieved by transforming a nondeterministic dynamic fault tree into a Markov automaton. From the optimized scheduler of this Markov automaton, an optimal recovery strategy can then be derived. The model of recovery automata is also introduced to represent these strategies. Finally, how these synthesized strategies can help improve overall system reliability is discussed