Certain inventory items are living organisms, for example livestock, and are therefore capable of growing during the replenishment cycle. These items often serve as various saleable food items downstream in supply chains. The purpose of this paper is to develop a lot sizing model for growing items if the supplier of the items offers incremental quantity discounts. A mathematical model is derive...

‎this paper proposes a multi-supplier multi-product inventory model in which the suppliers have unlimited production capacity, allow delayed payment, and offer either an all-unit or incremental discount. the retailer can delay payment until after they have sold all the units of the purchased product. the retailer’s warehouse is limited, but the surplus can be stored in a rented warehouse at a...

We consider inventory systems of “perishable” goods. Perishable goods cannot be carried from one period to another. Examples of perishable goods include newspaper, Christmas tree, and many grocery items like milk and banana. Here, a period could be one day, or one week, or any time frame that is appropriate in the application context. Suppose that a retailer sells a particular perishable produc...

In this paper we derive a new structural property for an optimal solution of the economic lot-sizing problem with time-invariant cost parameters. We show that the total holding cost in an order interval of an optimal solution is bounded from above by a quantity proportional to the setup cost and the logarithm of the number of periods in the interval. Since we can also show that this bound is ti...

The EOQ and EPQ models with linear and fixed backorder costs are newly analyzed and all formulae are proven using only algebra. Two cases are identified, where backorders should and should not be allowed. The results are shown to include several known special cases. r 2004 Elsevier B.V. All rights reserved.