Port integrated scheduling under uncertain operation time and cascade effects: A complex network structure entropy solution

Abstract

The integrated scheduling of quay cranes, yard cranes, and internal vehicles in a port allows for further optimization of resource allocation on a global scale. Since the scheduling objects are all mobile equipment and their mutual waiting time needs to be reduced as much as possible, new requirements are brought for integrated scheduling. Uncertain operation time is a common phenomenon in ports. How to ensure the effectiveness and robustness of integrated schedules under uncertainties is worth studying. Moreover, although the cascading effects of operation time fluctuation is an important factor affecting the robustness of schedules, less attention has been paid to it. To solve this problem, firstly, a mixed integer nonlinear programming model for integrated scheduling in a port that allows internal vehicles to travel deep into the yard is formulated. A genetic algorithm for solving the model is designed. Then, “gaps” between adjacent operations in schedules are focused on, and the complex network structural entropy theory is used to construct an anti-cascade effect and robustness evaluation index of schedules. In addition, a scheduling plan generation framework that gives a way to use the evaluation index is proposed. Specifically, the anti-cascade effect and robustness evaluation indices of scheduling plans whose objective function values are within a given threshold are calculated, and the final scheduling plan with the largest index is selected. Finally, the feasibility and effectiveness of the proposed method are verified by extensive experiments.