• Title/Summary/Keyword: Warranty Period

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Optimization of Improvement Level for Second-Hand Product with Periodic Maintenance Schedule (주기적인 유지보수 계획에 따른 중고제품에 대한 최적 향상수준)

  • Kim, Dae-Kyung;Kim, Jin Woo;Park, Dong Ho
    • The Korean Journal of Applied Statistics
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    • v.26 no.1
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    • pp.151-162
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    • 2013
  • Due to a growing demand for the second-hand product, especially for the expensive one, the warranty and maintenance policies for such products have been studied to improve the product reliability of late. In this paper we study a periodic maintenance model for the second-hand product which is purchased by the customer at the age of $x$. When purchased, the dealer provides a warranty of a fixed length during which the product is maintained periodically to reduce the failure rate of the product and thus, to improve the reliability after each maintenance is served. If a failure occurs between two successive maintenances, only minimal repair is conducted. As for the warranty policy, we adopt free non-renewing repair action on each failure, in addition to the periodic maintenance service during the warranty period. Thus, under the given warranty policy, all the maintenance and repair costs incurred during the warranty period are charged to the dealer. For the proposed periodic maintenance scheme, we formulate a cost model to evaluate the expected total cost charged to the dealer during the warranty period and derive an optimal upgrade level of the failure rate at each maintenance to minimize the expected total warranty cost from the perspective of the dealer. We also present numerical results for an optimal upgrade level based on the proposed methods.

Cost analysis for minimal repair model in stepdown warranty policy (단계별 보증제도에서 응급수리 모형에 관한 보증비용 분석)

  • 김재중;김원중
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.16 no.27
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    • pp.21-25
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    • 1993
  • This article is concerned with cost analysis in stepdown warranty policy. The repair of item is divided into two policies. First, perfect repair can be considered that the failurerate is the same as new item. Second, minimal repair is shown that the failurerate is the same as just before the item failure In this paper, the minimal repair model is introduced. And it is assumed that manufacturers repair the item failure within the warranty periodn. But warranty period is not renewed at all. At this point the warranty cost is analyzed in manufacturer's and customer's point of view.

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A Bayesian Approach to Replacement Policy with Extended Warranty (연장된 보증이 있는 교체정책에 대한 베이지안 접근)

  • Jung, Ki Mun
    • Journal of Applied Reliability
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    • v.13 no.4
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    • pp.229-239
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    • 2013
  • This paper reports a manner to use a Bayesian approach to derive the optimal replacement policy. In order to produce a system with minimal repair warranty, a replacement model with the extended warranty is considered. Within the warranty period, the failed system is minimally repaired by the manufacturer at no cost to the end-user. The failure time is assumed to follow a Weibull distribution with unknown parameters. The expected cost rate per unit time, from the end-user's viewpoints, is induced by the Bayesian approach, and the optimal replacement policy to minimize the cost rate is proposed. Finally, a numerical example illustrating to derive the optimal replacement policy based on the Bayesian approach is described.

A Study on the Direction of the Warranty Contract in Constructions (건설공사 성능계약제도 도입방향에 관한 연구)

  • Kim, Hyun;Park, Sung-Yong;Seo, Young-Chil;Lee, Sang-Beom
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2008.05a
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    • pp.153-157
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    • 2008
  • The construction market has gradually become complexity, variety and specialization, and then owner's requirements about quality has become various. In order to solve the problem such as stated above, advanced constructions in United Kingdom, Japan and United States have introduced warranty contract which is warranted to quality and performance for need of owner in determined term to ensure the quality of construction since 1960s. However, the interior of a country encounter another problem result from defects liability what indefiniteness of defects standard, excess responsibility period, social recognition of be identical fraudulent work and defects, and contract with ascendancy of owners. etc, so builders concerned more excess defects liability than the quality of construction. The purpose of this study is to analysis of warranty contract in order to solve the problem such as stated above.

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Preventive maintenance policy following the expiration of replacement-repair warranty (교체-수리보증이 종료된 이후의 예방보전정책)

  • Jung, Ki-Mun
    • Journal of Applied Reliability
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    • v.12 no.2
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    • pp.57-66
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    • 2012
  • In this paper, we consider the periodic preventive maintenance model for a repairable system following the expiration of replacement-repair warranty. Under this preventive maintenance model, we derive the expressions for the expected cycle length, the expected total cost and the expected cost rate per unit time. Also, we determine the optimal preventive maintenance period and the optimal preventive maintenance number by minimizing the expected cost rate per unit time. Finally, the optimal periodic preventive maintenance policy is given for Weibull distribution case.

Optimal Burn-In under Waranty

  • Kim, Kui-Nam;Lee, Kwang-Ho
    • Communications for Statistical Applications and Methods
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    • v.6 no.3
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    • pp.719-728
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    • 1999
  • This paper discusses an optimal burn-in procedure to minimize total costs based on the assumption that the failure rate pattern follows a bimodal mixed Weibull distribution. The procedure will consider warranty period as a factor of the total expected burn-in cost. A cost model is formulated to find the optimal burn-in time that minimizes the expected burn-in cost. Conditional reliability for warranty period will be discussed. An illustrative example is included to show how to use the cost model in prctice.

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A Bayesian approach to replacement policy following the expiration of non-renewing combination warranty based on cost and downtime (비재생혼합보증이 종료된 이후의 비용과 비가동시간에 근거한 교체정책에 대한 베이지안 접근)

  • Jung, Ki-Mun
    • Journal of the Korean Data and Information Science Society
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    • v.21 no.5
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    • pp.873-882
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    • 2010
  • This paper considers a Bayesian approach to replacement policy following the expiration of non-renewing combination warranty. The non-renewing combination warranty is the combination of the non-renewing free replacement warranty and the non-renewing pro-rata replacement warranty. We use the criterion based on the expected cost and the expected downtime to determine the optimal replacement period. To do so, we obtain the expected cost rate per unit time and the expected downtime per unit time, respectively. When the failure times are assumed to follow a Weibull distribution with uncertain parameters, we propose the optimal replacement policy based on the Bayesian approach. The overall value function suggested by Jiang and Ji (2002) is utilized to determine the optimal replacement period. Also, the numerical examples are presented for illustrative purpose.

A Warranty Policy with Replacement and Repair Periods (교체와 수리기간을 가진 보증정책)

  • 윤원영;유승효
    • Journal of the Korean Operations Research and Management Science Society
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    • v.20 no.1
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    • pp.55-62
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    • 1995
  • This paper compares the two policies which are unsed in Korean electronic appliance industry. Policy I is a general warranty policy under which all of failures during warrenty period (12 months) are repaired without charge. Policy II was proposed recently by a company. Under Policy II, when the product fails until a certain times(6 months), the failed product will be replaced by the new product and all other failures from the certain time to the warrenty period (24 months) will be repaired free. We obtain the expected total warranty costs per product and necessary conditions under which the Policy II has a meaning in economic point of view without or with discount rate. Some numericla examples are considered.

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Repair-Replacement Strategies for Warranted Items with Phase-Type Lifetimes (PH 수명분포를 갖는 보증제품의 수리-교체 전략)

  • Kim, Ho-Gyun;Rao, B. Madhu;Bae, Chang-Ok;Kim, Seung-Chul
    • Journal of Korean Institute of Industrial Engineers
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    • v.31 no.4
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    • pp.341-348
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    • 2005
  • This paper is concerned with the question of servicing warranties for repairable items. During the warranty period, each time an item fails the manufacturer has the obligation to restore the item to operational condition either by repairing the item or by replacing it with a new item. In this paper, we consider repair-replacement strategies based on the condition of the failed item. For products with phase-type lifetime distributions where the phases represent the condition of the item, we develop algorithms to determine the expected cost of servicing a warranty and use it in making the repair-replacement decision. Illustrative numerical examples are presented. We also propose a dynamic strategy by taking the expected remaining warranty cost into consideration.

Economic Evaluation of Early Detection System for Warranty Issues (품질보증 이슈 조기감지 시스템의 경제성 평가)

  • Jung, Sung-Hwan
    • Journal of Korean Society for Quality Management
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    • v.40 no.1
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    • pp.39-48
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    • 2012
  • An early detection system for warranty issues periodically collects customers' claim data and automatically reports alarms about emerging issues based on statistical algorithms. It helps companies to reduce an issue definition time and save the handling cost of warranty claims. This paper provides an evaluation framework to validate the economic effect of an early detection system project. For this purpose, we present economical index of a project with explicit formulas such as ROI(return on investment), PP(payback period), NPV(net present value), PI(profitability index) and IRR(internal rate of return) and analyze the sensitivities of the index according to the variation of project input parameters. The proposed analysis framework is expected to be used for evaluating economic values of various system integration projects.