中文摘要：

针对经典的计划评审技术不允许网络图中存在回路,而且假定所有活动时间服从β分布,使计划评审技术的使用受到限制的问题,通过将双代号网络映射为基于Petri网的模型,建立了既不改变双代号网络原有特性,又允许回路存在的基于Petri网的计划模型.结合Petri网可达图分析方法,在消减可达图的突发状态的基础上,引入矩母函数计算了PERT模型的性能参数.通过计算实例和仿真实验对比验证了该方法可以用于增强计划评审技术.

英文摘要：

Classic program evaluation and review technique（PERT） do not allow the existence of loop in activity on arrow（AOA）, and it should assume that all the activities time subject to the β probability distribution. These two restrictions limit the use of PERT. By mapping AOA network, this paper establishes the Petri nets based plan model that not only maintain the original properties of AOA, but also allow the existence of the loop. Meanwhile, combined with the analysis approach for Petri nets reachability graph and based on reducing the vanishing states of reachability graph, the performance parameters of PERT model can be calculated by introducing moment generating function （MGF）. Finally, this paper verifies the applicability of this method for enhancing PERT by comparison of calculation instance with simulation experiment.