• International Journal of Reliability and Applications
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• 제14권1호
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• pp.41-54
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• 2013

In this paper, cost analysis is conducted using inter-failure interval under renewable warranty subject to imperfect repair for multi-component system. One way to model the imperfect repair is to use the quasi-renewal process (Wang and Pham 1996). Two alternative quasi-renewal processes were suggested by Park and Pham (2010) using quasi-renewal process; first is an altered quasi-renewal process with random variable parameter and second is a mixed quasi-renewal process considering replacement service and repair service, simultaneously. In this study, we use the altered and mixed quasi-renewal processes and develop the warranty cost model to obtain the expected value of warranty cost and to help company make important decisions regarding the warranty policy. Numerical examples are used to demonstrate the applicability of the methodology derived in the paper.

• Journal of the Korean Data and Information Science Society
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• 제27권6호
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• pp.1557-1564
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• 2016

최근에 기본보증이 종료된 이후에 주어지는 시스템의 추가보증에 대한 사용자의 관심이 증가되고 있다. 따라서 본 논문에서는 사용자 측면에서 비재생보증 하에서의 이단계 보전정책을 제안하였다. 이단계 보전정책의 첫 번째 단계에서는 추가보증을 구입할 것인지의 여부를 결정하고, 두 번째 단계에서는 보증이 종료된 이후의 최적의 교체 주기를 결정한다. 이때, 추가보증 동안에 발생된 시스템의 고장에 대해서는 판매자에 의해서 무료로 최소수리가 이루어진다. 최적의 이단계 보전정책을 결정하기 위해서 사용자 측면에서 기대비용을 사용하였으며, 끝으로 시스템의 고장시간이 와이블 분포를 따를 때 수치적 예를 통하여 제안된 이단계 보전정책을 설명하였다.

• 품질경영학회지
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• 제20권1호
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• pp.39-47
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• 1992

This paper is concerned with cost analysis and determination of warranty period in a stepdown warranty policy. Manufacturer's warranty cost is analyzed for nonrepairable item, where the warranty is assumed to be renewed at any failure within the warranty period. It is shown that from this result in free replacement policy, pro-rata policy and hybrid policy can be easily calculated. The method of determining optimal warranty period is also explored.

• 품질경영학회지
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• 제19권1호
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• pp.103-114
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• 1991

This article is concerned with cost analysis in warranty policy. The warranty cost can be different according to warranty rate and warranty renewal policy. In this paper the stepdown warranty policy is analyzed. Assuming the nonrepairable item, manufacturer's cost is calculated in stepdown warranty policy and free replacement, pro-rata, hybrid policy. Numerical examples are given over Weibull time-to-failure distribution.

• International Journal of Reliability and Applications
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• 제12권1호
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• pp.41-48
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• 2011

This paper considers the maintenance model suggested by Jung and Park (2010) to adopt the Bayesian approach and obtain an optimal replacement policy following the expiration of NFRRW. As the criteria to determine the optimal maintenance period, we use the expected cost during the life cycle of the system. When the failure times are assumed to follow a Weibull distribution with unknown parameters, we propose an optimal maintenance policy based on the Bayesian approach. Also, we describe the revision of uncertainty about parameters in the light of data observed. Some numerical examples are presented for illustrative purpose.

• 산업경영시스템학회지
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• 제11권17호
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• pp.55-65
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• 1988

This article suggests the costs analysis of resumer's view under the stepdown warranty is renewd whenever a failure occurs in the warranty period. And the general warranty policy is showed such as free replacement policy prorata warranty policy, hybrid warranty policy. In this respect case, the cost of consumer is also calculated. In order to study the cost analysis of consumer. "RENEWAL THEORY" is introduced and the cost of consumer is calculated.alculated.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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• pp.686-691
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• 2005

We are 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 by a new item. In this paper, we consider the 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.

• 산업경영시스템학회지
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• 제10권15호
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• pp.23-32
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• 1987

This paper proposes a stepdown warranty policy: the warranty period consists of subintervals where the manufacturer's compensation is constant for warranty failures and decreases with the subinterval's number. Manufacturer's unit warranty cost is analyzed for both irrepairable and repairable products. we assume that only minimal repairs are performed for repairable items. Comparison with the free replacement polity indicates that the proposed policy has a longer warranty period if tile warranty reserves are the same and that manufacturer`s unit warranty cost is smaller if the warranty periods are tile same. Some numerical examples are also given.

• International Journal of Reliability and Applications
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• 제1권1호
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• pp.27-38
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• 2000

In a recent paper Iskandar ＆ Sandoh (1999) studied an opportunity-based age replacement policy for a system which has a warranty period (0,S]. When the system fails at age x $\leq$ S a minimal repair is performed. If an opportunity occurs to the system at age x, S $\leq$ x $\leq$ T, we take the opportunity with probability p to preventively replace the system, while we conduct a corrective .replacement when its fails in (S,T). Finally, if its age reaches T, we perform a preventive replacement, Under this policy the design variable is T. For the case when opportunities occur according to a homogeneous Poisson process, the long-run average cost of this policy was formulated and studied analytically by Iskandar & Sandoh (1999). The same problem is here analysed by using a graphical technique based on scaled TTT-transforms. This technique gives, among other things, excellent possibilities for different types of sensitivity analysis. We also extend the discussion to the situation when we have to estimate T based on times to failure.

• Communications for Statistical Applications and Methods
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• 제15권6호
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• pp.909-923
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• 2008

본 논문에서는 수리가 가능한 시스템에 대하여 혼합보증이 종료된 이후의 교체모형과 예방보전모형을 고려하는데, 만약 보증기간이 종료된 이후에 시스템에 고장이 발생하면 최소수리를 수행한다. 최적의 교체정책과 최적의 예방보전정책을 결정하기 위한 기준으로는 기대비용과 기대비가동시간에 근거한 총밸류함수를 사용한다. 그리고 시스템의 고장시간이 와이블분포를 할 때 수치적 예를 통해서 제안된 최적의 교체정책 및 예방보전정책을 자세히 설명하고자 한다.