求解CPM网络计划的最大网络时差

CPM网络计划的网络时差表示项目中各工序实际可使用的机动时间的总和(绝非理论上机动时间的简单加总),即CPM网络计划的总机动时间,它决定着在总工期不变的前提下,所有工序实际可以达到的最大工期的总和,与项目的成本管理和时间管理密切相关。网络时差是变量,取决于各工序的时间进度安排,说明可以通过调整工序的时间进度来决定该时差的取值,特别是其最大值,进而实现成本和时间优化。本文首先从新的角度分析了网络时差的含义;然后,在此基础上设计了求解最大网络时差的算法,其思路为,通过建立和分析最大网络时差模型,将其转化为特殊的“时间-费用权衡问题”,进而可运用Fulkerson算法等经典算法求解;最后,通过应用举例对该算法进行了演示。

Solving Maximal Network Float of CPM Network Planning

Network float of network planning denotes sum of floats which could be consumed practically by each activity in project, and it isn't the simple sum of floats in theory. Network float determines sum of the maximal reachable durations of all activities in practice under the condition of fixed total duration, and is closely correlative to cost management and time management of project engineering. The network float is variable, and is correlative to time schedule of each activity. It illustrates that value especial maximal value of the float could be decided the by adjusting time schedule of activities, and then realizes the optimization of cost and time. In this paper, firstly, the meaning of network float is analyzed from a new visual angle; secondly, algorithm to solve maximal network float is designed based on the above meanings, and the algorithm is that we transform the problem to especial “time-cost tradeoff problem” by founding and analyzing the model of maximal network float, which could be solved by using classic algorithm such as Fulkerson algorithm; and finally, the algorithm is demonstrated by an example.