Gilles Cormier

A review of warehouse models

Abstract Literature aimed at optimizing the throughput capacity, storage and design of warehouses is reviewed. Throughput capacity models are comprised of picking policies, batching policies, storage assignment policies, as well as dynamic control models. Storage capacity models either find the optimal warehouse size or else maximize space utilization. Finally, questions such as rack orientation, space allocation and external building configuration are the focus of warehouse design models.

On coordinating warehouse sizing, leasing and inventory policy

Abstract Organizations often fulfil their storage needs by supplementing their own warehouse with leased space, a scenario modeled here under the assumption of constant product demand. Closed-form formulae are obtained for the decision variables of interest, namely, the replenishment lot size and the warehouse size, as well as the amount of space to lease. Cost savings due to leasing are shown to have an upper bound of approximately 29% when the optimal warehouse capacity can be installed without restrictions (such as a budgetary constraint). A numerical example further indicates that leasing is significantly more beneficial when the warehouse size is tightly constrained, and that total costs are robust with respect to demand fluctuations.

Conceptual design of a warehouse for just-in-time operations in a bakery

Abstract This paper outlines some analysis and design principles for a central distribution facility to support a just-in-time (J.I.T.) operating philosophy, derived from a case study at a large bakery. Various facets of the study are presented, including the determination of storage and throughput requirements, a conceptual warehouse layout, and an economic analysis. The paper concludes with a description of an alternative design as well as a retrospective discussion on the potential use of operations research and computer simulation in such a study.

On Component Standardization

Abstract This paper proposes a nonlinear, nonconvex set partitioning model for selecting from a set of available components, each of which can fulfil certain requirements, a subset able to satisfy all requirements at minimal cost These components are assumed to have a very low value with respect to ordering costs (category C items such as nuts and bolts). A heuristic method which is easily implemented on a computer spreadsheet as well as an optimal branch and bound method are described. Finally, two more situations where standardization can be beneficial are presented in qualitative terms.

Preventive Maintenance and Joint Buffer Inventory for Parallel Machines

This paper presents an approach for jointly optimizing buffer inventory and preventive maintenance. Due to the complexity of the mathematical model, experimental design is used in order to determine the optimal values of the decision variables, namely, the maintenance periodicity and the inventory level. We have also proposed a decomposition method for the case of parallel machines. By including the value of the scale coefficient beta in our cost equations, we have determined a model able to adapt itself to numerous machines.