• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1995년도 춘계공동학술대회논문집; 전남대학교; 28-29 Apr. 1995
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• pp.675-675
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• 1995

• Communications for Statistical Applications and Methods
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• 제15권1호
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• pp.77-86
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• 2008

본 논문에서는 비재생보증이 종료된 이후의 최적의 주기적인 예방보전정책을 제안한다. 비재생보증기간이 종료된 이후의 예방보전에 대하여 Wu와 Clements-Croome (2005)의 확률적 보전효과를 갖는 주기적인 예방보전모형을 가정한다. 시스템의 운영 기간 동안 사용자가 지불하여 야 할 비용들이 주어져 있을 때 단위시간당 기대비용을 결정한다. 또한, 구해진 단위시간당 기대비용을 최소화하는 최적의 예방보전 주기와 횟수를 결정하는 방법을 다룬다. 마지막으로 본 논문에서 제안된 예방보전정책을 설명하기 위해서 수치적 예를 살펴본다.

• 한국산업정보학회논문지
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• 제7권1호
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• pp.66-74
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• 2002

판매되는 제품에 대한 보증비용은 소비자의 사용정도에 관계없이 일정하다고 가정한다. 하지만 현실적으로는 소비자들에 따라 사용 정도가 서로 다를 수 있다. 사용정도와 예방보수 형태는 보증비용 책정에 중요한 역할을 할 수 있다. 따라서, 본 논문에서는 소비자에 따라 사용정도가 다르고 예방보수 정책의 형태가 서로 다른 경우에 대한 제품의 기대보증 비용을 산출할 수 있는 새로운 보증비용 모형을 제시했다.

• 대한산업공학회지
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• 제31권4호
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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.

• International Journal of Reliability and Applications
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• 제3권3호
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• pp.113-124
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• 2002

This paper suggests the optimal periodic preventive maintenance policies after the combination warranty is expired. After the combination warranty is expired, a repairable system undergoes PM periodically and is minimally repaired at each failure. And also the system is replaced by a new system at the N th PM. In this case, we derive the mathematical formula for the expected cost rate per unit time. The optimal number and period for the periodic PM that minimize the expected cost rate per unit time are obtained. Some numerical examples are presented for illustrate purpose.

• 품질경영학회지
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• 제39권2호
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• pp.170-178
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• 2011

In general, a software fault detection phenonenon is described by a software reliability model based on a nonhomogeneous Poisson process(NHPP). In this paper, we propose a software reliability growth model considering the differences of the software environments in both the testing phase and the operational phase. Also, we consider the problem of determining the optimal release time and the optimal warranty period that minimize the total expected software cost which takes account of periodic software maintenance(e.g. patch, update, etc). Finally, we analyze the sensitivity of the optimal release time and warranty period based on the fault data observed in the actual testing process.

• 산업경영시스템학회지
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• 제18권33호
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• pp.87-92
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• 1995

This paper proposes age replacement policy in stepdown warranty policy. The replacement policy is considered in case of minimally repairable items. And renewal theory is used in analyzing warranty costs. The expected cost per unit time is presented in stepdown warranty policy, free replacement, prorata and hybrid policy. In this article it is assumed that item is replaced at the age of T but the any failure is minimally repaired before the age T. At this point the expected cost per unit time is shown in customer's view point. And numerical example is explored in weibull time-to-failure distribution.

• Communications for Statistical Applications and Methods
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• 제18권3호
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• pp.277-286
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• 2011

Global companies can sell their products with dierent warranty periods based on location and times. Customers can select the length of warranty on their own if they pay an additional fee. In this paper, we consider the warranty period and the repair time limit as random variables. A two-dimensional warranty policy is considered with repair times and failure times. The repair times are considered within the repair time limit and the failure times are considered within the warranty period. Under the non-renewable warranty policy, we obtain the expected number of warranty services and their variances in the censored area by warranty period and repair time limit to conduct a warranty cost analysis. Numerical examples are discussed to demonstrate the applicability of the methodologies and results using field data based on the proposed approach in the paper.

• 산업공학
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• 제15권3호
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• pp.286-296
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• 2002

Products which are sold with warranty, preventive maintenance actions by manufacturers and/or buyers have an impact on the total costs for both parties. In this paper, we develop the models to study the expected warranty cost for products with free repairable warranty with three types of discrete preventive maintenance. We deal with by utilizing the concept that preventive maintenance reduces the virtual age of the system. We assume that the maintenance planning horizon can be segmented into k discrete and equally sized periods. In such a scenario, numerical examples are presented.

• 산업경영시스템학회지
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• 제24권64호
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• pp.29-38
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• 2001

Most warranty studies assume that the usage intensity is the same for all buyers. However, in real life the usage intensity varies across the population of buyers. In the general case, one can divide the population into $\kappa$ categories. This has implications for manufacturers of products. Should a manufacturer produce one product and offer different warranties for the $\kappa$ groups or produce different products (one for each group) and offer the same warranty. A warranty cost analysis is needed to choose between these options. The analysis complicated by factors such as adverse selection , buyers attitude to risk and the price structure. In this paper we develop models to study the expected warranty cost for products with free replacement warranty with varying usage intensity. Numerical examples are presented.