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

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.