Browsing by Subject "Risk analysis"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    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.
  • No Thumbnail Available
    Item
    A fuzzy event tree methodology modified to select and evaluate suppliers
    (South African Institute of Industrial Engineering, 2020) Mizrak Ozfirat P.
    The supplier selection problem becomes more urgent as competition in the market increases. Quality, cost, and the timely delivery of a product mostly depends on the manufacturer’s suppliers and the materials supplied. Therefore manufacturers are very elaborate in selecting their suppliers and work hard to develop supplier selection strategies. In this study, event tree analysis (ETA) is used to solve a manufacturing firm’s supplier selection problem. ETA is a method that is traditionally used for risk analysis problems, combining the probabilities of risk occurrences subject to the necessary precautions. In this study, this structure is used to select and evaluate suppliers. An event tree is developed to analyse each possible supplier, with branching being used according to the supplier selection criteria. The probability of each branch is set as the performance value of the supplier according to the selection criteria. Finally, the supplier is evaluated by combining all performance values on an event tree basis. Fuzzy logic is also incorporated into the event tree methodology to decrease human error and the effect of uncertainty. Fuzzy triangular numbers are used to denote the performance values of suppliers, and fuzzy ranking is used to distinguish the suppliers into classes. The proposed methodology is applied to nine possible suppliers of a specific material. The results reveal that two of the suppliers dominate all the others in the fuzzy ranking. © 2020, South African Institute of Industrial Engineering. All rights reserved.