Replenishment policies for empty containers in an inland multi-depot system

This research focuses on the problem of positioning empty containers in a port area with multiple depots. Three options are considered: positioning from other overseas ports, inland positioning between depots and leasing. The policies for empty-container management are as follows: a coordinated (s, S) inventory policy for overseas positioning, a (ri) policy at each depot for inland positioning, and a simple leasing policy with zero lead-time and infinite capacity. For the inland positioning policy, four different methods are proposed to reposition empty containers between depots. The objective is to obtain the optimal policy in order to minimize the expected total cost consisting of: inventory holding, overseas positioning, inland positioning and leasing costs. A simulation-based genetic algorithm is developed to find near-optimal policies. Numerical examples are given to demonstrate the effectiveness of the proposed approach and examine the sensitivity of results with respect to system parameters.