【摘要】 基于规则系统是目前应用较为广泛的一类专家系统，但它的知识库不易维护。本文针对基于规则系统的一致性问题，应用图形化建模工具Ｐｅｔｒｉ网的可达性概念和状态方程分析方法，提出了基于Ｐｅｔｒｉ网的一致性检查方法。文中首先对规则的三种Ｐｅｔｒｉ网表示模型进行了比较，并在含约束Ｐｅｔｒｉ网模型基础上，提出了一致性检验的命题方法，最后以实例说明该方法的实现步骤。当规则库较大时，相应的Ｐｅｔｒｉ网模型可能也会很庞大，这有可能引起计算量大、知识爆炸等问题，对此本文建议采用子标识处理和网络分块方法，以避免这些问题的发生。更多还原

【Abstract】 Although the rule based system is widely used as an expert system,it is difficult to maintain its knowledge base.As far as the consistency problem of knowledge base are concerned,a Petri net based method is presented in this paper with the applications of Petri nets’ reachability concept and state equation.Firstly,there introduces and compares three candidate Petri net models for representing rules,and then presents some propositions about verification on the basis of the model selected.Finally,an example is illustrated to explain the usage of those propositions.However,the Petri net model will become enormous when the corresponding rule base is large,which is apt to result in some problems,such as large computing and knowledge explosion etc..In this paper,two methods,called submarking and subnets,are supposed to avoiding such problems.更多还原