Modeling Multi-Objective, Multi-Product and Multi-Period Supplier Selection Problem Considering Stochastic Demand

In this paper, a multi-objective, multi-period and multi-product mixed integer programming model ‎for the supplier selection and quota allocation problem under an all-unit quantity discount policy, ‎constrained storage space and stochastic demand is considered. Also, due to the stochastic status of ‎the demand, we use the Chance Constrained Programming (CCP) in order to transform the inventory ‎balance equation to a stochastic position. Since the discount policy encourages the buyer to buy more while the storage capacity restricts, we require to consider both in the supplier selection and quota allocation problem; furthermore, different priorities for the objectives should be considered. We use the LP-metric method, goal programming and the novel solution technique ‎called multi-choice goal programming in order to model the multi-objective problem. Furthermore, a numerical ‎example using three modeling approaches, considering the different scenarios are solved. The differences ‎in the scenarios are the importance of the objective function in terms of the decision maker. Results ‎show if an objective function is prioritized, that objective will be closer to its optimal value.