Supplier Selection

Since a large number of the oil and gas projects are related to the supply chain, the selection of contractors and suppliers is very important. In projects, a contractor is obliged to supply the goods from suppliers and manufacturers approved by the clients, while most companies in Iran, including the company surveyed in this research, i.e. Iranian Offshore Engineering and Construction Company (IOEC, do not have a scientific approach to this issue). The main objective of this research is providing a scientific and practical approach to ranking suppliers and contractors at IOEC and selecting the best ones. In order to achieve such an objective, an integrated model of Swing and TOPSIS methods with fuzzy approach has been designed and applied to a real case. The actual data used are obtained from the post-lay survey of the exports and infield pipelines of South Pars development phases 13, 14, and 22. <strong>Keywords</strong>: Supplier Selection, multi attribute decision making (MADM), Oil and Gas, IOEC, Swing, Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), Fuzzy, Pipelines

One of the most important parts of the green supply chain management (GSCM) is the green supplier. The green supplier selection process has a vague nature. Therefore, specific approaches, such as fuzzy, are necessary during their evaluation. On the other hand, the choice of a coherent and integrated strategy is vital to achieve lean and green production. Accordingly, the present study aimed to select suppliers based on lean green production indicators by goal programming, fuzzy DEMATEL and quality performance expansion. The statistical population of this study consisted of personnel (managers, assistants and experts) with 16 managers and assistants and 46 experts. In this research, the Cochran formula (including error percentage of 5%) was used to determine the number of statistical samples. Accordingly, 53 experts from Pars Khodro Company participated as a sample (by simple random sampling method). In order to analyze the data, fuzzy DEMATEL methods, expansion of fuzzy performance quality and goal programming were used. According to the findings of the present study, continuous improvement to achieve lean green indicators is the main element of the production system at Pars Khodro Company. The important aspect of determining how much damage would be bestowed on the best supplier, so that it would be possible to determine the least amount of damage in sum, was reviewed in this section. In other words, the lowest possible losses are based on the suffering of the current  losses, the supplier and in which level of losses it has the most optimal status.

Objective : The Supply chain plays a key role in adapting the organization to variable conditions and an uncertain future. The selection of appropriate suppliers can significantly increase the competitiveness and ability of a business in the market. One of the essential factors in supply chain optimization is controlling and managing inventory cost. This paper aims to simultaneously optimize supplier selection and order allocation while considering inventory control using a fractional programming approach.  Methodology: The methodology integrates quantitative analytical techniques in a multi-phase approach. First, the most frequent supplier selection criteria are identified with a literature review. The Delphi method was used to select the supplier selection criteria. In the next step, fuzzy Shannon entropy determines criterion weights. Then, fuzzy EDAS calculates supplier performance scores. Finally, fractional programming facilitates supplier selection and order allocation. Results : The most frequent supplier selection criteria were extracted from the literature review. In the Delphi technique, experts ultimately agreed on six key criteria: price, quality, delivery, flexibility, responsiveness, and financial stability. The results of the Shannon entropy analysis indicate that flexibility, with a weight of 0.20, holds the highest relative importance among the criteria. The suppliers score obtained from the fuzzy EDAS method is used as one of the parameters of the mathematical model. Conclusion : The proposed hybrid MADM approach and mathematical model have been validated using empirical data obtained from Sirjan Steel Company. The result shows that the hybrid MADM approach and fractional programming have high accuracy in selecting the best supplier.