An ant colony algorithm for yard truck scheduling and yard location assignment problems with precedence constraints

This paper examines the yard truck scheduling, the yard location assignment for discharging containers, and the quay crane scheduling in container terminals. Taking into account the practical situation, we paid special attention to the loading and discharging precedence relationships between containers in the quay crane operations. A Mixed Integer Program (MIP) model is constructed, and a two-stage heuristic algorithm is proposed. In the first stage an Ant Colony Optimization (ACO) algorithm is employed to generate the yard location assignment for discharging containers. In the second stage, the integration of the yard truck scheduling and the quay crane scheduling is a flexible job shop problem, and an efficient greedy algorithm and a local search algorithm are proposed. Extensive numerical experiments are conducted to test the performance of the proposed algorithms.