论虚工作是单双代号网络图的实质性区别

单代号网络图与双代号网络图区别的主要形式是其符号含义的互换。由于符号含义互换带来它们之间某些时间参数计算和关键线路确定的方法不同,但是这些不同都是当双代号网络图存在虚工作时引起的。所以单双代号网络图除符号含义不同之外,其时间参数计算的实质区别取决于双代号网络图中有无虚工作。针对网络计划一实例分析了虚工作造成的实质性区别,说明了这种实质性的区别在网络计划应用中的重要性。

Differences between Activity-on-Arrow Network and Activity-on-Node Network Based on Dummy Activity

The difference between activity-on-arrow network and activity-on-node network is the symbol exchange,which brings the variations on the time index calculation and critical path.These variations are caused by the dummy activity in activity-on-arrow network;hence,the main difference between activity-on-arrow network and activity-on-node network lies in whether the dummy activity exists in activity-on-arrow network.Taking an example,the differences are caused by the dummy activity.Dummy activity is important in the application of network planning.