Nowadays, Companies have to deal with an uncertain demand which is more difficult to handle when it has a non-stationary pattern. Simultaneous decrease of customer service and increase of stock costs are the most significant effects of such demand uncertainty. To deal with this issue, inventory optimization models must be adapted to cover a multi-echelon network structure and to consider altern...

We study a class of two echelon, serial systems with identical ordering capacities or limits for both echelons. For the case where the lead time to the upstream echelon is one period, the optimality of state-dependent, modified echelon base-stock policies is proved using a decomposition approach. For the case where the upstream lead time is two periods, we introduce a new class of policies call...

Most research on supply chain management deals with settings where firms do not voluntarily get rid of inventory in the system. Since voluntary inventory reductions are often observed in practice, in this paper, we propose a (multi-echelon) model where the firm can dispose of excess stock through sales in the secondary market at each stage in the supply chain. What are called nested echelon bas...

This paper reviews inventory models with multiple supply options and discusses their contribution to supply chain management. After discussing strategic aspects of supplier competition and the role of operational flexibility in global sourcing, inventory models which use several suppliers in order to avoid or reduce the effects of shortage situations are outlined. Further, related inventory pro...

A two-stage inventory system is considered where Poisson demand occurs at Stage 1, and Stage 1 replenishes its inventory from Stage 2, which in turn orders from an outside supplier with unlimited stock. Each shipment, either to Stage 2 or to Stage 1, incurs a fixed setup cost. Under the assumption that the supply leadtime at Stage 2 is zero, we characterize a simple heuristic policy whose long-...

In supply chain networks, the flow of material occurs between various business entities such as suppliers, manufactures, distributors and retailers, which can be considered as the various echelons (levels) in a multi-echelon supply chain network. Spare parts supply chain management deals with optimizing stocking, purchasing, repairing and disposing activities of purchased parts and their compon...

This paper considers an inventory system responsible for repairable equipments located at several operational sites, each in different area. When a failure occurs at the operational site, spare parts are required. We analyze a multiple-supplier inventory system that includes an internal repair shop that offers several modes of repair with different repair times and an external supplier of spare...