Tedarikçi seçimi için melez bir yaklaşim: Petrol piyasasinda bir uygulama

In an increasingly competitive and rapidly changing business environment, supplier evaluation process and supplier selection decision are considered as some of the key issues faced by companies to survive. This thesis provides a hybrid approach to solve the supplier selection problem which includes qualitative and quantitative factors affecting the decision-making process. Companies can increase profitability and gain competitive advantage by deciding the best supplier. However, this decision becomes complicated in case of multiple suppliers, multiple conflicting criteria, and imprecise parameters. In this thesis, a literature review was performed on supplier selection problem. A new hybrid approach is provided to solve a supplier selection problem by the use of a defined technique, which derives from fuzzy sets theory, Analytic Hierarchy Process (AHP), and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), Goal Programming (GP). Evaluation criteria are indicated by experts and the objectives of the problem are determined. Supplier selection criteria are weighted using Fuzzy AHP method because of the uncertainty and vagueness of the experts' opinion. Alternative suppliers are evaluated and ranked by Fuzzy TOPSIS method. Then, the problem is modelled in terms of GP approach and solved via LINDO to offer a different perspective for decision making process. After the comparison of results, the most suitable supplier is selected by the decision maker using proposed hybrid approach among the alternatives for satisfying the firm's requirements. Finally, the proposed framework is illustrated through a case study in the Turkey petroleum market because of vital importance of supplier selection in the market. Five main evaluation criteria and twenty-two sub-criteria are used to select most suitable fuel oil distribution company for filling station in Turkey. The proposed methodology is applied for 5-years partnership contract. The results show that the proposed approach is very well-suited as a decision-making tool for supplier selection decisions.