Browsing by Subject "Analytic hierarchy process"

Now showing 1 - 5 of 5
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    A fuzzy analytic hierarchy process methodology for the supplier selection problem
    (World Scientific Publishing Co. Pte Ltd, 2012) Ozfirat P.M.; Tuna G.; Tuncel G.
    Purchasing activities of a company form a very important part in the operation of the company. The quality of production and services mainly rely on the performance of the suppliers. In addition, a large amount of the product's total cost belongs to the purchasing cost of its materials. Therefore, selecting the most suitable suppliers is very important for the firm. Unfortunately, most of the time, suppliers cannot provide the highest quality parts on-time at the lowest costs in the market. In other words, quality, delivery and cost objectives conflict with each other. In this study a fuzzy analytic hierarchy process approach is employed for the supplier selection problem of a textile company. First the selection criteria according to company's objectives are determined. Then the pair-wise comparisons are made on a fuzzy basis. Similarly, in the next step, the six alternative suppliers are compared by fuzzy means. Finally, the two suppliers which achieved the highest performance are advised to the company.
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    Integrating multi criteria analysis and clustering techniques for the segmentation of after-sale spare part inventory
    (Computers and Industrial Engineering, 2014) Güçdemir H.; Ilgin M.A.
    Timely and cost effective supply of spare parts is a vital issue in after sales service. If the demand for spare parts is overestimated, holding costs increase. Underestimation of demand results in lost goodwill of the customers. In order to manage the spare part inventories effectively, companies generally determine the importance level of each spare part and apply a suitable inventory control policy. In this study, we integrate clustering techniques and analytic hierarchy process (AHP) to determine the importance levels of spare parts kept by a television manufacturer. First, spare parts are grouped into 3 main categories using clustering algorithms. Then AHP is used to determine importance level of each group by considering several criteria including frequency, criticality, total monthly usage, lead time, availability, substitutability and tendency of obsolescence. Finally, suitable inventory policies are suggested for each spare part group.
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    A new risk analysis methodology integrating fuzzy prioritization method and failure modes and effects analysis; [Bulanik önceliklendirme metodu ve hata türü ve etkileri analizini birleştiren yeni bir risk analizi yöntemi]
    (Gazi Universitesi Muhendislik-Mimarlik, 2014) Mizrak Özfirat P.
    As technology develops and production amounts increase, work health and safety is getting more important in order to prevent accidents before happening and to prevent production line from stopping. Proactive measures are quite important in order to prevent accidents. In order to define proactive measures, threats in the work area should be classified and risk analysis should be made. In this study, one of the modern risk analysis methods, Failure Modes and Effects Analysis (FMEA) is integrated with fuzzy logic. By this way, FMEA would provide more realistic results. In the methodology developed, the three criteria defined in FMEA which are probability, severity and detection are handled with fuzzy prioritization method which is one of fuzzy analytic hierarchy process (FAHP) techniques. Risks defined are evaluated according to all three criteria and importance coefficients of risks are obtained. Then these coefficients are turned into degrees defined in FMEA and risk priority numbers (RPN) are calculated. By integrating FAHP and FMEA, RPN calculation becomes more objective and independent from the analyst. The methodology developed is applied to mining sector which is one of the most risky sectors both in Turkey and in the world.
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    Integration of fuzzy analytic hierarchy process and multi-objective fuzzy goal programming for selection problems: An application on roadheader selection
    (IOS Press BV, 2015) Ozfirat P.M.; Ozfirat M.K.; Malli T.; Kahraman B.
    In this study a general methodology employing fuzzy analytic hierarchy process and fuzzy goal programming is developed for selection problems. The proposed methodology has two main sub-phases. In the first phase, fuzzy triangular numbers are used in order to represent the comparisons among decision criteria. Then lower and upper bounds as well as mid-values of priorities belonging to each decision criteria are computed. In the second phase these values and fuzzy triangular numbers are entered into the goal programming model and the model is solved to give the final priorities of decision criteria. Then the weighted sum of ratings for each selection alternative are found where the weights are final priorities from goal programming model. The proposed methodology is presented on a real life roadheader selection problem from mining industry. The results revealed that the methodology is easily applicable and provides satisfactory results. © 2015 - IOS Press and the authors. All rights reserved.
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    Selection of coal transportation mode from the open pit mine to the thermic power plant using fuzzy analytic hierarchy process
    (Vilnius Gediminas Technical University, 2018) Özfirat P.M.; Özfirat M.K.; Malli T.
    Coal produced in open pit mines should be moved to thermic power plants for production of power. Thermic power plants require very large amounts of coal. In transportation process of this coal, both costs and technical parameters should be considered. Common alternative transportation modes in this process are belt conveyors, truck types, suspension rail conveying systems, pipelines and railways. Selection of one of these modes is influenced by transportation distance, inclination of the haulage road, amount of coal reserve, investment costs, production capacity and unit production cost of the open pit mine. In this study, advantages and disadvantages of alternative transportation modes are analysed using Fuzzy Analytic Hierarchy Process (F-AHP). The results revealed, belt conveyors and trucks transportation by are superior to others. © 2016 Vilnius Gediminas Technical University (VGTU) Press.