On Two New DynamicProgramming Procedures As Efficient As the WagnerWhitin RegenerationPoint Type in Dynamic Lot Sizing For a dynamic lot sizing problem involving timevarying deterministic demand of a single item, Wagner and Whitin (1958) have developed an efficient regenerationpoint dynamic programming (DP) approach under a special cost assumption. The purpose of this paper is twofold: First, Bellmanu0027s standard DP type can be made as efficient as the regenerationpoint DP when the special property is appropriately exploited, although the resulting DP requires one more state variable. This is because the regeneration point DP computes a sum of multiple stage costs by summation, while the standard DP computes it by DP recurrence relations. Second, we relate those two DP methods to yet another DP that solves an associated minimum cost flow network problem. We then show that those three DP procedures are equally efficient by describing their insightful relations and features.

Simulation of Allocation Policies for a Serial Inventory System under Advance Demand Information In this paper, we simulate allocation policies for a twostage inventory system that receives perfect advance demand information (ADI) from customers belonging to different demand classes. Demands for each customer class are generated by independent Poisson processes while the processing times are deterministic. All customers in the same class have the same demand lead time (the difference between the due date and the requested date) and backordering costs. Each stage in the inventory system follows orderbasestockpolicies where the replenishment order is issued upon arrival of a customer order. The problem requires a fast and reliable method that determines the system performance under different policies and ADI. Thus, we employ discreteevent simulation to obtain output parameters such as inventory costs, fill rates, waiting time, and order allocation times. A numerical analysis is conducted to identify a reasonable policy to use in this type of system.