Mehdi Jafarian

Abstract: In this paper, a new approach that applies fuzzy Delphi method in Simple Additive Weighting (SAW) is proposed to be used in the Maintenance Strategy Selection Problem (MSSP). This approach is based on representation of the importance of goals and each strategy capabilities to satisfy each maintenance goals with fuzzy numbers. Fuzzy Delphi method is applied for the assessment of the importance of each goal and capability of each maintenance strategy, considering the expert’s opinion. This method considers both tangible and intangible goals dealing with the selection problem. Fuzzy Delphi method generates an L-R fuzzy number that measures information about the nature of opinions more adequately. Yager ranking method is used in transforming fuzzy numbers in the selection problem. Finally, through a heuristic algorithm, the main steps of the proposed method are presented.

Abstract: As has been mentioned in the literature, distribution centers location problem (DCLP) is a multiobjective problem. Cost (or distance) minimization is the primary objective in this area. While significance of each relation between a distribution center (DC) and a customer/retailer is different, it has not been considered seriously. By adapting available facility and new facility concepts of the multifacility location problem with costumer/retailer and a DC respectively, a utility function as the second objective based on the importance has been used. These importances are in decision maker (DM) s’ mind which should be quantified to be of use for modeling purpose. We propose a method for the uncapacitated single stage facility location problem (UFSLP) in which a fuzzy AHP method is used to achieving these importances. So we present a multiobjective model in which minimizing total cost is first objective and maximizing the utility function is the second one. LP-metric method is used to solve our multiobjective model. Finally, a numerical example is expressed for illustration of the proposed method.