Vendor selection and order allocation using an integrated fuzzy case-based reasoning and mathematical programming model

A basic part of the logistic management of companies is the purchasing function, and the appropriate selection of vendors and allocating orders among them is one of the prime responsibilities of this function. Many conceptual and analytical models have been developed for addressing the vendor selection problem (VSP). This paper focuses on a case-based reasoning (CBR) approach which is a recently recommended method for solving the VSP by making use of previous similar situations. Having applied fuzzy set theory in the proposed model--as a novel innovation--the vague nature of some selection criteria has been incorporated by utilizing the linear membership function of fuzzy type to quantify the vagueness in decision parameters. Moreover, a mixed integer programming model is employed to simultaneously consider suitable vendor selection and order allocation; due to the purchase situation of vendors derived from the CBR system, and with respect to such realistic constraints as meeting the buyer's demand, vendors' capacity, etc.