一种基于动态故障树的SBDD方法

Method of SBDD Based on Dynamic Fault Tree

在分析基于Pandora的动态故障树时,SBDD方法未考虑各底事件间复杂的关系,造成生成的SBDD中存在无效分支,即计算的不交化割集中存在无效割集。针对该问题,提出了一种基于动态故障树的SBDD方法,可以动态删除无效节点,避免无效分支的产生。该方法主要包括两个方面:基于结构式排序方法的关系式排序方法和动态优化SBDD生成算法。关系式排序方法的基本思想是利用故障树的结构关系和底事件间的关系给底事件赋予不同的排序优先级。在底事件排序队列的基础上,使用动态优化SBDD生成算法来生成SBDD。在计算过程中,该算法动态删除无效的节点,使结果中不存在无效割集。实验结果表明,在相近的时间内,使用基于动态故障树的SBDD方法生成的SBDD规模更小,不交化割集数目更少且不存在无效割集。

When analyzing the dynamic fault tree of Pandora,the method of SBDD doesn＇t take into account the com- plex relations between events. It causes that the generated SBDD has invalid branches where there are invalid cut sets in the non-intersect minimum cut sets. Aiming at this problem, an improved method of SBDD was proposed in this paper which can remove invalid node dynamically and avoid invalid branches. The improved method of SBDD mainly includes two aspects, the relation sorting method based on the structure sorting method and the dynamic optimization generation algorithm of SBDD. The basic idea of the relation sorting method is giving the events different sorting priority based on the structure relations of the fault tree and the relationship between events. The dynamic optimization generation algo- rithm of SBDD is used to calculate the SBDD based on the event sequencing queue. In the process of calculation,the al- gorithm removes invalid node dynamically and makes the results don＇t contain invalid cuts. Experiments show that the SBDD gaxerated hy the improved method of SBDD is smaller and the non-intersect minimum cut sets are less and don＇t contain invalid sets in a approximate time.