• Title/Summary/Keyword: Spare Part Management

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Optimal pricing and spare parts manufacturing strategy for EOL (end-of life) services

  • Kim, Bo-Won;Ko, Deok-Soo
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2005.05a
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    • pp.938-946
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    • 2005
  • We study the firm's strategy to price its products and plan the spare parts manufacturing so as to maximize its profit and at the same time to fulfill its commitment to providing the customers with the key parts continuously over the relevant decision time horizon, i.e., the production plus warrantee period. To examine the research question, we developed and solved a two-stage optimal control theory model. Our analysis suggests that if the cost to produce the spare part during the warrantee period is more expensive than that during the production period, the firm should increase its sales price gradually throughout the production period to control its sales. In addition, during the production period it is optimal for the firm to produce the spare parts more than needed so that the overproduced spare parts can be used to partially meet the demand during the warrantee period. We conducted numerical analysis to investigate the sensitivity dynamics among key variables and parameters such as inventory holding cost, unit spare part production costs, part failure rate, and parameters in the demand function.

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A FOQ Model for Spare-Part Inventory Control (예비품(豫備品) 재고관리(在庫管理)를 위한 정량발주모형(定量發注模型))

  • Jeong, Sang-Il;Sin, Ju-Hang;Park, Yeong-Taek
    • Journal of Korean Society for Quality Management
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    • v.18 no.2
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    • pp.9-17
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    • 1990
  • This paper deals with a FOQ( ; fixed-order quantity) model for spare-part inventory control. In a spare-part inventory problem, stock depletion arises not from external market demand but from internal demand resulting from failures of parts in use. The problem differs from the classical inventory problem in that the demand for a failed part never arises more during stockout period, since the unit remains inoperative when stockout occurs until the failed part is replaced by new one. In the problem under consideration, n identical units are operating simultaneously and failed one is replaced immediately by new one if on-hand spares remain. In order to replenish spares, an order with quantity Q is placed whenever the number of on-hand spares falls to levels. The average annual cost of operating the spare-part inventory system is derived under the assumption that both lifetime of a part and replenishment lead-time distributions are exponential.

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Spare Part Optimization of MIME Systems using Simulation and Genetic Algorithms under Availability (가용도 제약하에 MIME 시스템에서 유전알고리즘과 시뮬레이션을 이용한 수리부속 최적화)

  • Chung, Il-Han;Yun, Won-Young
    • Journal of Korean Society for Quality Management
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    • v.36 no.2
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    • pp.9-19
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    • 2008
  • Spare part problem of MIME (Multi Indenture Multi Echelon) system under availability constraint has been studied for several decades. In most of existing studies, it was very difficult to obtain the optimal numbers of spare parts and some approximate methods were proposed under many restrictions. In this paper, we consider a simulation to estimate the total cost rate and system availability and a genetic algorithm to obtain the optimal numbers of spare parts. Some numerical examples are also studied.

Long-Term Demand Forecasting Using Agent-Based Model : Application on Automotive Spare Parts (Agent-Based Model을 활용한 자동차 예비부품 장기수요예측)

  • Lee, Sangwook;Ha, Chunghun
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.38 no.1
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    • pp.110-117
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    • 2015
  • Spare part management is very important to products that have large number of parts and long lifecycle such as automobile and aircraft. Supply chain must support immediate procurement for repair. However, it is not easy to handle spare parts efficiently due to huge stock keeping units. Qualified forecasting is the basis for the supply chain to achieve the goal. In this paper, we propose an agent based modeling approach that can deal with various factors simultaneously without mathematical modeling. Simulation results show that the proposed method is reasonable to describe demand generation process, and consequently, to forecast demand of spare parts in long-term perspective.

Some New Results on Uncertain Age Replacement Policy

  • Zhang, Chunxiao;Guo, Congrong
    • Industrial Engineering and Management Systems
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    • v.12 no.1
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    • pp.41-45
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    • 2013
  • Age replacement policy is a commonly policy in maintenance management of spare part. It means that a spare part is always replaced at failure or fixed time after its installation, whichever occurs first. An optimal age replacement policy of spare parts concerns with finding the optimal replacement time determined by minimizing the expected cost per unit time. The age of the part was generally assumed to be a random variable in the past literatures, but in many situations, there are few or even no observed data to estimate the probability distribution of part's lifetime. In order to solve this phenomenon, a new uncertain age replacement policy has been proposed recently, in which the age of the part was assumed to be an uncertain variable. This paper discusses the optimal age replacement policies by dealing with the parts' lifetimes as different distributed uncertain variables. Several results on the optimal age replacement time are provided when the lifetimes are described by the uncertain linear, zigzag and lognormal distributions.

An (s, S) spare-part inventory model with general leadtime (일반적인 조달기간을 갖는 (s, S) 예비품 재고 모형)

  • 박원재;박영택
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1996.04a
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    • pp.285-288
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    • 1996
  • This paper deals with an (s, S) spare-part inventory model with general leadtime. In the model, if the inventory level falls to a reorder point s, a replenishment order quantity Q is ordered. Assumming that the number of operating units is one and the lifetime of a unit follows an exponential distribution, we derive the expected cost rate and suggest a procedure to obtain the optimal pair of (s, S) minimizing the cost rate.

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An (S-1, S) Spare-Part Inventory Model for Multi-Stage Machine Repair Problem (다단계 기계수리문제의 (S-1, S) 예비품 재고정책에 관한 연구)

  • Seo, Yong-Seong;Jeong, Sang-Hwan;Park, Yeong-Taek
    • Journal of Korean Society for Quality Management
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    • v.19 no.1
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    • pp.129-140
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    • 1991
  • This paper deals with on (S-1, S) spare-part inventory model for multi-stage machine repair problem with attrition. The steady-state availability of the system is maximized under some constraints such as total cost, available space etc.. The problem is formulated as a closed queueing network and the system availability is calculated by Buzen's computational algorithm. In order to find the optimal numbers of spare units and repair channels for each operating stage, the problem is formulated as a non-linear integer programming(NLIP) problem and an efficient algorithm. which is a natural extension of the new Lawler-Bell algorithm of Sasaki et el., is used to solve the NLIP problem. A numerical example is given to illustrate the algorithm.

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The Computing Model of Demand Quantity for Optimal Current Spare Parts considering the Operational Availability under Budget (예산제약 하에서 운용가용도를 고려한 최적 동시조달수리부속품 소요 산출 모델)

  • Na, In-Sung;Lee, Kye-Kyong;Park, Myeong-Kyu
    • Journal of the Korea Safety Management & Science
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    • v.8 no.5
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    • pp.167-180
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    • 2006
  • This study expands limitation of OASIS(Optimal Allocation of Spares for Initial Supports) program, which calculates CSP(Concurrent Spare Part), not only availability but also cost, and developed the program enabling run in WINDOW OS. By considering multi-step repair and logistics support system, repairing capability at the time of deployment, and procurement period, this model is the first local model reflecting circumstances of the armed forces of the Republic of Korea. Furthermore, the programmed model was selected as the military standard software and has being essentially used for CSP calculation.

Simultaneous Optimization of Level of Repair and Spare Parts Allocation for MIME Systems under Availability Constraint with Simulation and a Meta-heuristic (가용도 제약하에 시뮬레이션과 메타 휴리스틱을 이용한 MIME 시스템의 수리수준 및 수리부속 할당 동시 최적화)

  • Chung, Il-Han;Yun, Won-Young;Kim, Ho-Gyun
    • Korean Management Science Review
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    • v.26 no.1
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    • pp.209-223
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    • 2009
  • In this paper, an analysis problem of repair levels and spare part allocation for MIME(Multi indenture multi echelon) systems is studied using simulation and meta-heuristics. We suggest a method to determine simultaneously repair levels and spare parts allocation to minimize the life cycle cost of MIME system under availability constraint. A simulated annealing method is used to analyze the repair levels and genetic algorithm is used to obtain the optimal allocation of spare parts. We also develop a simulation system to calculate the life cycle cost and system availability. Some numerical examples are also studied.

(s, S) Spare Part Inventory System

  • Park, Young-Taek
    • Journal of Korean Society for Quality Management
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    • v.14 no.2
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    • pp.21-27
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    • 1986
  • This paper deals with a continuous review (s,S) spare part inventory system. The distributions of service life of each part and the replenishment lead time are assumed to be exponential. Assuming that there is never more than a single order outstanding, we obtain the average annual cost of operating the inventory system. If the length of stockout period is small enough to be neglected compared to the length of operating period, the optimal operating policy variables minimizing the cost rate can be calculated iteratively. For the case of one-for-one ordering (that is, s=S-1), an exact cost rate, and a closed form decision rule minimizing the cost rate are obtained for a more general situation in which more than one order is allowed to be outstanding and the distribution of the replenishment lead time is general.

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