This paper deals with an inventory system with one central warehouse and a number of identical retailers. We consider perishable-on-theshelf items; that is, all items have a fixed shelf life and start to age on their arrival at the retailers. Each retailer faces Poisson demand and employs (1, T) inventory policy. Although demand not met at a retailer is lost, the unsatisfied demand at the centr...

Almost all multi-echelon inventory models assume that demand not satis ed immediately can be backordered. In some situations this assumption is not realistic. For example, it may be more representative to model stockouts as lost sales when the retailers are in a competitive market and customers can easily turn to another rm when purchasing the good. Assuming lost sales at the retailers, we cons...

In this paper, the cost function for a three-echelon inventory system with two warehouses is derived. Transportation times are constant and retailers face independent Poisson demand. Replenishments are one-for-one. The lead time of a retailer is determined not only by the constant transportation time but also by the random delay incurred due to the availability of stock at the warehouses. We co...

In this paper, we establish the convexity of important cost functions in a general class of multi-echelon inventory models. In particular, we first study an assembly system with a single finished product managed using an echelon order-up-to policy. We show that the shortage penalty cost over any horizon is jointly convex with respect to the base-stock levels and capacity levels. Our second resu...

This paper studies a periodic-review, serial inventory system in which echelon r nQ T policies are implemented. Under such a policy, each stage reviews its inventory in every T period and orders according to an echelon r nQ policy. Two types of fixed costs are considered: one is associated with each order batch Q, and the other is incurred for each inventory review. The objective is to find the...

This article addresses the development of an integrated supplier selection and inventory control problems in supply chain management by developing a mathematical model for a multi-echelon system. In particular, a buyer firm that consists of one warehouse and N identical retailers wants to procure a product from a group of potential suppliers, which may require different price, ordering cost, le...

We study a multi-item, two-echelon, continuous-review inventory problem at a Dutch utility company, Liander. We develop a model that optimizes the quantities of service parts and their allocation in the two-echelon network under an aggregate waiting time restriction. Specific aspects that we address are emergency shipments in case of stockout, and batching for regular replenishment orders at th...