堵塞网络中最小饱和流的灵敏度分析

由于流动单元的随机流动，在网络结构堵塞点处经常会发生堵塞，网络堵塞最严重时的饱和流是最小饱和流，它小于最大流值。网络当前的饱和流反映了网络的实际流通能力，以网络最大流为设计流通能力的网络中，发生堵塞时实际流通能力经常达不到设计流通能力。为缓解网络的堵塞．可以通过扩充某些弧容量的方法。由于网络中存在一类弧，增加这类弧容量不仅不能改善网络的堵塞程度，有时反而会更加恶化网络的流通性能。本文利用网络最大堵塞截面的性质．分析了改变截面中的弧容量时对最小饱和流的影响，结果表明最大堵塞截面中增加正向弧的容量可以改善网络的堵塞程度，而增加反向弧的容量不仅不能改善网络的堵塞，有时甚至会使最小饱和流减少。

Sensitivity Analysis on the Minimum Saturated Flow of Blocking Networks

In transport networks,especially in the case of emergency,the stochastic flow blocks network often at the(structural) blocking node.When the blockage is the most serious in the network,the saturated flow should be the minimum saturated flow.It is less than the maximum flow.The current saturated flow is just the practical flow capability of the network.If the maximum flow is regarded as the design flow capability in the network,the saturated flow often couldn't reach the maximum flow.To improve the blockage of the network,enlarging the capacities of some arcs is a directing idea.There existed some arcs in the network,adding their capacities couldn't improve the degree of blockage,even worse off.We first find the maximum blocking cut of the network,analyze the influence on the minimum saturated flow with changing the capacities of the arcs.The results show that adding capacities of the forward directed arcs could improve the degree of blockage,however,adding the capacities of the backward directed arcs couldn't improve the blockage of the network and sometimes lessen the minimum saturated flow.