Supplier Selection and Order Size Determination in a Supply Chain by Using Fuzzy Multiple Objective Models
Seyed Ali Ayazi, Javad Siahkali Moradi and Turan Paksoy
During recent years, determining supplier selection in the supply chain has become very important as a core competency for organizations. Trying to establish an effective and long term communication and cooperation with suppliers can play an important role in strengthening and balancing of supply chain. However, the nature of supplier selection is a complex multi-criteria problem that includes both quantitative and qualitative factors. These factors may be in conflict and may also be uncertain and it needs adequate methods to be evaluated. This process is becoming more complex when a group of decision makers have to make some controversial decisions. In this paper, we tried to utilize a fuzzy programming method to determine the order size from each supplier and apply different criteria that are in contrast with each other. For solving this problem we first determined the related weight of each variable in the objective function by utilizing a fuzzy VIKOR method. In VIKOR model we assumed that compromising is acceptable for conflict resolution and decision makers want a solution that is the closest to the ideal solution, and the alternatives are evaluated according to all established criteria. Also linguistic values are used to assess the ratings and weights for these factors. These linguistic ratings can be expressed in fuzzy numbers. After obtaining weights of variables by Fuzzy VIKOR, constraints were determined. Then with contribution of fuzzy VIKOR prioritization, the weight of each alternative (supplier) is calculated. Then we put each alternative with its weight in a multiple objectives model to determine order size of each alternative. Solving the fuzzy multiple objectives model leads us to each supplier’s order size. Finally for solving the Fuzzy MODM (Multiple Objective Decision Making) we apply α-cuts and calculated different results in relation to every α-cut.
Keywords: Supplier prioritization, Order Size Planning, Fuzzy MODM, Fuzzy MADM, Fuzzy VIKOR, α-cut.