Optimization of Empty Container Allocation for Regional Sea Port Group with Dry Port Involved

A multi-period mixed integer programming model is developed to optimizing the operation of empty container repositioning among seaports and inland dry ports.Transport between dry ports is incorporated into the empty container repositioning process in addition to usually used seaport-seaport or seaport-land freight station transport, allowing the empty containers to be transported through any node of the network.This design helps to circulate empty containers in higherefficiency.Land transport cost, sea transport cost, storage cost, container leasing cost and constraint factors, such as storage capacity of nodes and transport capacity, are taken into consideration.The reposition process is optimized for the lowest cost under the condition of meeting the demand of ports.A practical problem, as an example, is solved with the model to find the optimal reposition plan for a given period of time.The result is compared to the situations where no transport between dry port is available or the dry ports are just normal land freight stations, demonstrating the effectiveness of the model.