Performance reliability of polymorphic systems by fuzzy fault tree based on T-S model

T-S fuzzy fault tree is a kind of fault tree constructed by a series of T-S gates with IF-THEN logic. This can solve the multi-state issue, uncertainty of failure mechanism, and that failure rate of the basic event is not accurately known in complex systems. Currently, this method mainly analyzes the system function failures. As a result, system has different performance reliability under different fault conditions. In practice, many of the internal failures of complex polymorphic systems often cause performance degradation, and multiple performance status appears. By using the expectation theory of statistics, giving performance variable for system and different performance values at different fault conditions, a method analyzing the performance reliability of a polymorphic system has been proposed. This method can also compute conditional expected performance reliability in condition of knowing the basic event's or middle event's failure. The performance reliability of avionics full duplex switched ethernet(AFDX), which is currently used on large aircraft, is analyzed by this method.