Using path optimum algorithm to solve slot selection problems for outbound containers of different attributes in container terminals

Abstract

The outbound container slot selection problem (OCSSP) is a hot topic in the field of port research and of great significance to improving the operational efficiency of container yards. With the initial stacking state and extractive sequence of containers being known, the goal is to accomplish the task of extracting all containers in the container block with a minimum number of container relocations. OCSSP is an NP-hard problem. To obtain more practical research results, this paper proposes an improvement to the existing model and presents an improved version of the path optimum algorithm that considers container attributes. With the objective of improving the overall operational efficiency of container terminal yards, this study analyzed some practical issues related to container extraction by taking into consideration the influences of extraction priority levels, movements of obstruct containers, the Manhattan distances of gantry crane, and other factors on the model. Finally, the paper distills some scheduling strategies applicable to OCSSP in the hope of providing a theoretical basis and practical guidance to container port operators for the better allocation and optimization of coastal container ports resources.