METAPRIME, an Interactive Fault Tree Analyser

The performances of almost all available fault tree analysis tools are limited by the performance of the prime implicant computation procedure they use. All these procedures manipulate the prime implicants of the fault trees in extension, so that the analysis costs are directly related to the number of prime implicants to be generated, which in practice makes these tools di cult to be applied on fault trees with more than 20000 prime implicants. This paper introduces an analysis method of coherent as well as noncoherent fault trees that overcomes this limitation because its computational cost is related to neither the number of basic events, nor the number of gates, nor the number of prime implicants of these trees. We present the concepts underlying the prototype tool METAPRIME, and the experimental results obtained with this tool on real life fault trees. These results show that these concepts allow us to completely analyse in seconds fault trees that no previously available technique could ever partially analyse, for instance noncoherent fault trees with more than 10 20 prime implicants. The concepts that we present here can also be used for the analysis of event trees because such trees denote Boolean functions on which these concepts can be applied. Prime implicant computation is a problem that is also critical in many other domains, in particular in arti cial intelligence applications such as reasoning maintenance and multiple fault diagnosis. The application of the concepts underlying METAPRIME to the resolution of these problems is under study.