【摘要】 故障树是事件间的一种布尔逻辑关系模型，基于故障树的诊断方法的广泛应用由于实际故障树分析过程NP困难问题而受到妨碍。Petri网作为一种特殊的有向网，它能反映系统的状态变化和事件发展，尤其适合于表达故障的传播关系。本文因此提出了两种基于Petri网的改进方法，与下行法相比，用该方法寻找最小割集和最小路集能有效地节省计算时间，提高推理速度和效率，并且其算法便于计算机实现。更多还原

【Abstract】 Fault tree is considered as a logic model of fault events, however, the diagnostic methodbased-on fau1t tree are preavnted from widespreading because there exists NP dlfficulty problems in theactual process of fault tree analysis. Petri net is a particular directed net which can reflect states’changesand events’evaluation of a system,and specially is suitable for describing the fault propagation. Therefore,two methods based on Petri nets are proposed to improve FTA in this paper. Compared with the down-search method,the two ones have the following advantages in 100king for the minimal cutting sets and min-imal path sets, such as deducing the computing time, increasing the reasoning rate and efficiency. Andmore,they are convenient to make arithmetic program in computer.更多还原