we present an improved implementation of the wagner-whitin algorithm for economic lot-sizing problems based on the planning-horizon theorem and the economic- part-period concept. the proposed method of this paper reduces the burden of the computations significantly in two different cases. we first assume there is no backlogging and inventory holding and set-up costs are fixed. the second model ...

This paper is concerned with the coordination of inventory control in divergent multiechelon inventory systems under periodic review and decentralized control. All the installations track echelon inventories. Under decentralized control the installations will decide upon replenishment policies that minimize their individual inventory costs. In general these policies do not coincide with the opt...

We study a single product inventory system with nonnegative setup cost in which the demand is a continuous random variable but orders are restricted to be integer valued. Optimal policies, when there are no setup costs, have a nice form. However, we show that, when the setup costs are nonzero, optimal policies may have a very counterintuitive form without any particular structure. We obtain a b...

This paper studies a competition in a decentralized supply chain between two independent suppliers who sell their products to a common retailer, under sales-rebate contract, and wherein the demand is sensitive to retail prices. The inventory related operational costs are included in the chain based on the economic order quantity model. The conditions of existence and uniqueness of the retailer’...

Intuition may lead to the hypothesis that in stochastic inventory systems a higher demand variability results in larger variances and in an increase of total expected system costs. In a recent paper, Song [5] formally proved this assertion to hold for a certain class of inventory models (including the Newsboy Problem), given a particular definition of variability. Here we use stochastic dominan...

We consider the problem of determining the optimal ordering and reordering policy for an inventory where the entire stockwill simultaneously become obsolete at some (typically random) time, T . Manymanufacturing, publishing, distribution, and high tech businesses face the challenge of maintaining inventories that do not age in the conventional sense; instead, they suddenly become obsolete and l...

The paper provides a new approach to study the problem of optimal control of two-item inventory model with deteriorating items. The total cost includes the sum of the holding costs of inventory, the holding costs of one item due to the presence of other and the production costs. The solution of optimal control problem of two-item model will be carried out using Pontrygin principle. The controll...