Resumen
The development of world-class international shipping centers has proved that there isn?t a specific pattern for the development of the freight collection and distribution system. Measures should be taken to give a full play to integrated advantages by generally considering the layout of the collection and distribution system of the port and in the rear. This article, following closely the multi-center tendency of the hub port and the integrated development of regional ports in the improvement of the essential functions of international shipping, presents an initial idea on the construction of the optimization model for the collection and distribution system in which regional ports both cooperate and compete with each other. Establishing a model combining transportation mode selection and route selection would eventually realize the network flow distribution and derive the results for hub port selection made by the hinterland, i.e. the port-hinterland collection and distribution volume and the throughput of the port. Specification and verification of the generalized cost function plays a pivotal role in the improvement of the model. In accordance with the layout of ports for Shanghai international shipping center and based on the optimization model for the freight collection and distribution system of ports with minimized generalized cost, a series of generalized cost functions for road sections of various transportation forms including highway, waterway and railway as well as for transfer hubs were established, and major parameters were defined. The software STAN for freight analysis was used to accomplish the network equilibrium assignment for overall system and data concerning the annual throughput and distribution of major hub ports were thus obtained. The output and data analysis show that Shanghai international shipping center is gradually developing into a multi-center overseas transportation hub, that the overall service capacities for major hub ports have been enhanced and that though the proportion of waterway freight transportation is on the rise, the highway freight collection and distribution system still needs to expand the scope of the transportation organization.