贝叶斯网络又称信度网络，是Bayes方法的扩展，是目前不确定知识表达和推理领域最有效的理论模型之一。从1988年由Pearl提出后，已经成为近几年来研究的热点.。一个贝叶斯网络是一个有向无环图(Directed Acyclic Graph,DAG),由代表变量结点及连接这些结点有向边构成(Bayesian network, also known as belief network, is an extension of Bayes method and one of the most effective theoretical models in the field of uncertain knowledge expression and reasoning. Since it was proposed by pearl in 1988, it has become a research hotspot in recent years. A Bayesian network is a directed acyclic graph (DAG), which is composed of representative variable nodes and directed edges connecting these nodes)