Exact and Approximate Evaluation of Batch-Ordering Policies for Two-Level Inventory Systems

We consider a two-level inventory system with one warehouse and N identical retailers. Lead times (transportation times) are constant and the retailers face independent Poisson demand. In a previous paper, we derived a recursive procedure for determining the policy costs for an average item in case of one-for-one replenishment policies. In this paper, we show how these results can be used for the exact or approximate evaluation of more general policies where both the retailers and the warehouse order in batches. We compare our methods to the method recently suggested by A. Svoronos and P. Zipkin.