A complete and an incomplete algorithm for automated guided vehicle scheduling in container terminals

Abstract

In this paper, a scheduling problem for automated guided vehicles in container terminals is defined and formulated as a Minimum Cost Flow model. This problem is then solved by a novel algorithm, NSA +, which extended the standard Network Simplex Algorithm ( NSA ). Like NSA , NSA + is a complete algorithm, which means that it guarantees optimality of the solution if it finds one within the time available. To complement NSA +, an incomplete algorithm Greedy Vehicle Search ( GVS ) is designed and implemented. The NSA + and GVS are compared and contrasted to evaluate their relative strength and weakness. With polynomial time complexity, NSA + can be used to solve very large problems, as verified in our experiments. Should the problem be too large for NSA +, or the time available for computation is too short (as it would be in dynamic scheduling), GVS complements NSA +.