Optimal ECR in General Inland Transportation Systems with Uncertainty: Periodic Review

This chapter consists of two parts. In the first part, we consider the optimal ECR problems for general inland transportation systems with multiple interconnected depots over multiple time periods. On the one hand, there are laden and empty container flows between depots. On the other hand, each depot is facing external supply and demand of empty containers, which means empty containers may enter or exit the system at each depot. Three stochastic dynamic programming models are formulated based on periodic review mechanisms including (i) a multi-depot transportation system without transfer seaports; (ii) a multi-depot transportation system with transfer seaports; (iii) an intermodal multi-depot transportation system with transfer seaports. In the second part, facing the challenge of dynamic decision making in stochastic systems, various optimization methods are introduced to solve the optimization problems. Specifically, we discuss the applications of approximate dynamic programming methods, simulation methods, metaheuristic optimization methods, stochastic approximation methods, perturbation analysis methods, and ordinal optimization methods. Their relative advantages and disadvantages are explained. Finally, a summary and a note are provided.