Network Flow with Intermediate Storage: Models and Algorithms

Abstract

Various network flow models, such as a flow maximization, a time minimization, a cost minimization, or a combination of them, have already been investigated. In most of the cases, they are considered subject to the flow conservation constraints. Here, we investigate the network flow models with intermediate storage, i.e., the inflow may be greater than the outflow at intermediate nodes. We introduce a maximum static and a maximum dynamic flow problem where an intermediate storage is allowed. Then, polynomial time algorithms are presented to solve these problems in two terminal general networks. We also study the earliest arrival property of the maximum dynamic flow in two terminal series-parallel networks and present its efficient solution procedure with intermediate storage. Moreover, we introduce a dynamic contraflow model with intermediate storage and present a polynomial time algorithm to solve the maximum dynamic contraflow problem in two terminal networks. We also solve an earliest arrival contraflow problem with intermediate storage. Our investigation is focused to solve the evacuation planning problem where the intermediate storage is permitted.