基于逻辑确定性的BDD变量排序方法

BDD Variable Ordering Method Based on Logistic Certainty

基于二维决策图(Binary Decision Diagram,BDD)的战时油料保障可靠性分析,其中一个关键是对变量进行排序,所选择的变量排序对BDD的规模有重要影响。由于阶段之间的相关性,单一阶段任务BDD变量排序方法很难直接应用于多阶段任务。考虑多阶段任务结构和特性的基础上,分析总结现有方法中影响变量排序的因素,提出了基于逻辑确定性的BDD排序方法。通过与传统的排序方法比较,改进的方法可以生成更理想的BDD结构。

Variable ordering is the key to the reliability analysis of wartime fuel reliability based on the binary decision dia- gram （BDD）. The order of the selected variables has an important impact on the size of the BDD. Due to the correlation between stages, the single-stage task BDD variable ordering method is difficult to apply directly to multi-stage tasks. Considering the structure and characteristics of multistage tasks, this paper analyzes and summarizes the factors that affect the variable ordering in the existing methods and proposes a BDD ordering method based on logical certainty. Compared with the general ordering method, the improved method can generate more ideal BDD structure.