THE WAREHOUSE SCHEDULING PROBLEM - FORMULATION AND ALGORITHMS

The Warehouse Scheduling Problem is a deterministic multi-item invento ry problem with a restriction on warehouse floor space available. We f ormulate a mixed integer nonlinear programming problem for the objecti ve of minimizing long run inventory holding and order costs per unit o f time. We integrate algorithms for staggering orders, described in co mpanion papers, with a heuristic to choose the order sequences. The re sult is called Sequenced Staggering. We describe a new algorithm to ge nerate order frequencies, called the powers-of-two-factor-of-three tec hnique, as a generalization of Roundy's roundoff technique for powers- of-two policies. We report on a computational study of four hybrid alg orithms for solving the warehouse scheduling problem, including the co mpeting algorithm of Gallego, Queyranne, and Simchi-Levi. Based on the se results, we recommend the combination of powers-of-two frequencies with Sequenced Staggering.