Inventory Ordering System with Fuzzy Parameters in Supply Chain

Nasiri, Mohsen | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 44220 (01)
  4. University: Sharif University of Technology
  5. Department: Industrial Engineering
  6. Advisor(s): Hajji, Rasool
  7. Abstract:
  8. Inventory control has been always considered important due to its prominent role in managing and better application of resources in the field of operational systems. Ordering system or review stock policy in supply chain management can be mentioned as one of the inventory control study fields of management. A lot of researches have been done in investigating ordering system in supply chain under certainty conditions; however, since the real world is full of uncertainties, parameters such as demand cannot be predicted exactly and we encounter with ambiguity. In this case, using crisp (exact) values can cause to decide wrongly (a wrong decision). On the other hand, due to absence of sufficient knowledge and data, using statistical methods seems unwise.
    For this reason, in this thesis, an approach is presented for using fuzzy numbers in ordering systems inventory control related decision making. The problem is investigating continuous and periodic review policy inventory in the linear two-level supply chain under uncertainty. In this supply chain, there are two enterprises, A and B that the A enterprise responds to fuzzy demand of customer. This enterprise orders its demand based on its inventory control policy to the B enterprise. Moreover, the B enterprise obtains its demand based on its inventory control policy from a supplier with an infinite capacity. Both of these enterprises have a warehouse that its capacity for inventory position is limited. Also storages in two enterprises are backorder.
    Since uncertainties in parameters of our problem are due to lack of information and knowledge, fuzzy theory is used for considering them, and the membership functions of parameters are fuzzy trapezoidal number. The centroid method is used for defuzzification, which is the most applied method for defuzzification. The most important fuzzy parameter is the customer’s demand that is given to the A enterprise. Other fuzzy parameters are the space cost, the holding cost, and the shortage cost.
    Focusing on cost control and satisfying a defined and predetermined service level for both enterprises have been done in the objective function of our problem. Considering fuzzy conditions of the problem, centralization and decentralization approaches in chain is developed and these approaches are compared for both ordering politics through a numerical example. Then this comparison is analyzed to choose the better approach
  9. Keywords:
  10. Supply Chain Management (SCM) ; Fuzzy Theory ; Inventory Control ; Continuous Review Policy ; Decentralized Supply Chain ; Centralized Approach

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