因果图向故障树转换的研究

因果图模型可以表示整个复杂系统中各因素见的复杂因果关系，故障树是故障分析和安全可靠性分析的常用模型，如果因果图模型能够转换为故障树模型，将扩大因果图的应用范围，方便故障树建模。因此研究因果图向故障树的转换显得十分重要。文章在分析故障树与因果图概念和表示符号的基础上，提出了因果图转换为故障树的算法。通过因果图向故障树转换可以得到任何事件为顶事件的故障树模型，然后可以采用成熟的FTA方法进行分析，这样因果图模型中的一些问题也可以采用故障树的方法来解决。在假设因果图中的连接事件表示必然因果关系条件下，因果图可以转换为含有可能的因果关系的故障树。研究表明通过微因果树化，因果图可以转换为故障树，所以因果图模型具有广泛的适用性和应用前景。

Study on the Conversion of Causality Diagram to Fault Tree

Causality diagram is able to express complex causalities among all factors in complicated system, while Fault Tree Analysis (FTA) is a very popular technique for the dependability modeling and fault analysis. It is important to discuss the conversion of causality diagram to fault tree (FT) because it will extend the application of causality diagram and make for modeling of FT if causality diagram can be mapped into FT. An algorithm for converting causality diagram into fault tree is proposed in this paper after the concepts and symbols of causality diagram and fault tree are analyzed. The conversion can get FT about any event that can be analyzed by FTA, so some problems in causality diagram can be solved by FT. Supposing that connecting event in causality express necessary causality, causality diagram can be converted into fault tree including possible causality .Its result indicates that causality diagram can be converted into fault tree at some condition by mini causality tree, and causality diagram has a popular application foreground.