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...

In this paper, we study a multi-echelon uncapacitated lot-sizing problem in series (mULS), where the output of the intermediate echelons has its own external demand, and is also an input to the next echelon. We propose a polynomial-time dynamic programming algorithm, which gives a tight, compact extended formulation for the two echelon case (2-ULS). Next, we present a family of valid inequaliti...

in this paper, a supplier-retailer transportation system is investigated as a two-echelon environment. there is a single location in each echelon; the unique supplier at the first echelon has to replenish the retailer's warehouse at the second echelon. by the way, the shortage situation should be avoided. for this situation, a model is provided based on the traditional eoq model. the inven...

Trade credit is a crucial source of capital particularly for small businesses with limited financing opportunities. Inventory models considering trade have been widely studied. However, while there extensive research on the single-vendor single-buyer inventory model allowing delays in payments, systems where vendor supplies to more than one buyer received less attention. In this paper, we analy...

This paper examines the cost-reduction effect of “postponed” routing decisions in a two-echelon supply chain. When a delivery vehicle leaves the warehouse with system replenishment quantities, it sequentially makes routing decisions to choose the next retailer to visit. To measure this effect this paper studies combined vehicle routing and inventoryallocation policies designed to minimize total...

We consider a single-product inventory system that serves multiple demand classes, which differ in their shortage costs or service level requirements. We assume a critical-level control policy, and show the equivalence between this inventory system and a serial inventory system. Based on this equivalence, we develop a model for cost evaluation and optimization, under the assumptions of Poisson ...

this study aims to minimize the total cost of a four-echelon supply chain including suppliers, an assembler, distributers, and retailers. the total cost consists of purchasing raw materials from the suppliers by the assembler, assembling the final product, materials transportation from the suppliers to the assembler, product transportation from the assembler to the distributors, product transpo...