In this paper we develop an approximate model of an inventory control system in which there exist two options for resupply, with one having a shorter lead time. Because the optimal policy appears to be extremely complex, we consider a reasonable extension of the standard (Q, R) policy to allow...

This paper considers an inventory system which maintains stock to meet both high and low priority demands. This model is suggested by the operation of a spare parts pool in a military depot: high priority demands are those which might result in the grounding of an aircraft, for example, while...

This paper develops two stochastic models of an internal mail delivery system in which a single clerk picks up, sorts and delivers mail to a closed loop of offices. The two models differ in whether deliveries are made at scheduled times or not. For a model in which all mail picked up each round...

We consider (S - 1, S) policies for a single item whose lifetime is fixed and known with certainty. Demands are generated by a stationary Poisson process and there is a positive leadtime for replenishment. We believe this study gives the only analysis for perishables with a positive order...

This paper considers the problem of describing optimal issuing policies when the field life, X(s), is a nonnegative random variable. A new optimality criterion involving stochastic ordering is introduced and sufficient conditions given for the optimality of FIFO and LIFO. Two specific models of...

We consider the problem of ordering perishable inventory when there is uncertainty in both the demand and the lifetime of the product. Under the assumption that units outdate in the same order in which they enter inventory, it is shown that the structure of the optimal policy is essentially the...

In this paper we consider the problem of finding a "good" lot size and reorder point policy for an inventory which is subject to continuous exponential decay. Examples of decaying inventories include alcohol, certain types of food items, and radioactive materials. The method of analysis is an...

This paper considers a retailer inventory system with N first-echelon stores and a single second-echelon distribution center (DC). Customer demands at the stores are assumed to be random. When a stockout occurs, customers are willing to wait for their order to be filled with a known probability....

This paper treats a depot-warehouse system in which demand occurs at the warehouse or retail level. This work differs from a number of other studies in that we allow item demands to be correlated both across warehouses and also correlated in time. Our motivation for this generalization arises...

Recent work in describing optimal ordering policies for perishable inventory casts the problem as a multi-dimensional dynamic program, the dimensionality being one less than the useful lifetime of the product, m. As m becomes large the computational problem becomes severe so that developing...