采用网络方法建立系统的模型,进行系统分析和系统设计的方法,近二十年来得到迅速发展和广泛应用。网络分析法中,计划协调技术(PERT)和关键路线法(CPM)出现最早应用也极为广泛。但是,传统的PERT和CPM技术没有考虑在计划执行过程中存在的不确定性和可变性,以及由此而造成的汇合偏差。因而往往导致分析上的偏差和失误。经验表明,采用这一传统方法制订计划总是偏于乐观,其偏差可 The network method to establish the system model, system analysis and system design methods, the rapid development and widespread use of the past two decades. Among the network analysis methods, the earliest applications of PERT and CPM are also widely used. However, the traditional PERT and CPM techniques do not consider the uncertainties and variability present in the execution of the plan, and the consequent convergence errors. Which often lead to analysis of the bias and error. Experience shows that there is always a bias toward optimism in adopting this traditional method of planning