Bilevel optimization for the reorganization of inland river ports: A niche perspective

To address the problems of duplicate construction, disorderly competition, small scale, and weak functionality, we examine the reorganization optimization of an inland river port group to realize its coordinated development. Considering port customers' decision-making behaviors, we propose a bilevel programming model for inland river port group reorganization based on niche theory. More specifically, an upper-level model is used to develop a reorganization plan, including the inland river port spatial layout and expansion extent, to maximize the value contributed by the port group to its region and industry and minimize the competition among the ports from the perspective of port management. More specifically, two upper-level objectives can be creatively measured by niche breadth and niche overlap. A lower-level model oriented to port customers aims to reduce their respective logistics costs by designing a transportation plan and providing feedback to the upper-level model to facilitate adjustments for port group reorganization. Since the dynamic interaction between the upper- and lower-level models significantly increases model complexity, we develop a hybrid heuristic algorithm by incorporating a genetic algorithm and an exact solution method. To verify the applicability of the proposed model and the efficiency of the developed hybrid approach, we conduct a series of numerical experiments on a real-world case study concerning Jining City, Shandong Province, China. Our case study also provides managerial insights into investment scale, land-use intensification, and the balance of planning objectives that may be useful for port managers.