• 산업경영시스템학회지
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• 제13권21호
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• pp.19-24
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• 1990

This paper deals with a problem of choosing an optimum inspection period for an equipment with two stages of failures. Stage I failure which can be detected only through inspection detenorates the equipment and causes critical stage II failure after a random period of time. The expected average cost function is obtained and an optimum inspection policy is discussed. A numerical example is also worked out.

• 품질경영학회지
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• 제21권2호
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• pp.109-120
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• 1993

Most systems are composed of components which have different failure chracteristics. Since the failure characteristics of components is different, it is rational and reasonable to establish a maintenance model to be considered repair and replacement policies which are proper to failure characteristics of these components. This paper proposes the age replacement time for a system composed of components which have different failure characteristics. In this model, it is assumed that a system is composed of a critical failure component, a major failure component, minor failure component. If any failure occurs to critical component before its age replacement time, the system should be replaced. If any failure does not occur until its age replacement time, preventive replacement should be performed at age replacement time T. Major component is minimal repaired if any failure occurs during operation. Minor component should be replaced as soon as failure is found. This paper determines the optimal replacement time of the system which minimize, total maintenance cost and initial stock Quantity of minor component within this optimal replacement time. Numerical example illustrates these results.

• 한국신뢰성학회지:신뢰성응용연구
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• 제6권3호
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• pp.195-203
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• 2006

This paper deals with cost analysis model in periodic maintenance policy. The repair policy with minimal repair is considered as follow : as the occurrence of failure between minimal repair and periodic interval time, unit is replaced by a new unit before the periodic maintenance time comes. Then total expected cost per unit time is calculated according to time delta t in a view of customer's. The total expected costs are included repair and usage cost : operating, fixed, minimal repair, periodic maintenance and new unit expected cost. Numerical example is shown in which failure time of item has Normal distribution.

• 산업경영시스템학회지
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• 제20권43호
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• pp.357-364
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• 1997

After the buyer purchases the product, the seller's role does not end. If the product fails to function properly before the end of the warranty period, the seller is responsible for its repair or replacement under the seller's warranty policy. There are two common types of warranty policies: the free replacement warranty and the rebate warranty. Under the free replacement warranty policy, replacement or repairs during the warranty period are provided by the seller free of charge to the buyer. Under the rebate warranty policy, a failed item is replaced by a new one or is repaired at a cost to the age of the failed item. The rebate warranty is most often used for items such as a battery or an automobile tire which wear out and must be replaced at failure. This paper proposes a easy way of estimating the warranty cost under the free replacement warranty policy assuming an exponential product failure function on repairable products.

• 벤처창업연구
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• 제10권3호
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• pp.15-26
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• 2015

본 연구의 목적은 국내에서 활발히 시행되고 있는 기업가정신 정책(entrepreneurship policy)에 대한 이론적 기반을 제공하는 것이다. 먼저 기업가정신 정책은 기업가적 과정에 정부가 개입하는 활동으로, 기업가정신을 가진 개인들의 공급을 증가시키고 그들의 창업활동을 지원하는 정책으로 정의하고, 이를 벤처기업정책 및 중소기업정책과 구분한다. 기업가정신 정책의 경제적 당위성과 관련하여서는 기업가 시장(market for entrepreneur)의 개념을 상정하고, 시장실패의 관점에서 정부의 개입 필요성을 도출하며, 정책수립의 원칙을 제시한다. 또한 기업가적 과정을 토대로 하여 기업가정신 정책의 틀을 모형화 하고, 정책영역별 파급경로(transmission channel)를 파악한다. 기업가정신 정책의 파급경로는 (1) 수요측면, (2) 공급측면, (3) 창업의사결정, (4) 자원조달 등이다. 마지막으로 각 정책영역 및 파급경로별로 구체적인 정책수단 혹은 프로그램들을 유형화하고, 이 기준에 따라서 실제로 우리나라에서 수행되고 있는 기업가정신 정책들을 분류한다. 하지만 본 연구는 기업가정신 정책에 대한 실험적인 경제 분석이므로 기업가정신 정책에 대한 연구목적이나 정책수립목표에 따라서 접근방법 및 내용이 달라질 수 있다.

• Journal of the Korean Data and Information Science Society
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• 제14권2호
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• pp.393-403
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• 2003

In this paper, various replacement policies for the general failure model are considered. There are two types of failure in the general failure model. One is Type I failure (minor failure) which can be removed by a minimal repair and the other is Type II failure (catastrophic failure) which can be removed only by a complete repair. In this model, when the unit fails at its age t, Type I failure occurs with probability 1-p(t) and Type II failure occurs with probability p(t), $0{\leq}p(t){\leq}1$. Under the model, optimal replacement policies for the long-run average cost rate and the limiting efficiency are considered. Also taking the cost and the efficiency into consideration at the same time, the properties of the optimal policies under the Cost-Priority-Criterion and the Efficiency-Priority-Criterion are obtained.

• 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.

• Communications for Statistical Applications and Methods
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• 제6권2호
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• pp.403-412
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• 1999

A block replacement policy where at failure the item is either replaced by a new or used item or remains inactive until the next planned replacement is considered. in this paper our interests are focused on reusing all the used items created by the policy. Numerical results for the case where the underlying life distribution is gamma are obtained.

• Journal of the Korean Data and Information Science Society
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• 제16권2호
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• pp.263-270
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• 2005

The reliability guarantee insurance policy for parts and materials was introduced to the market in 2003. This policy indemnifies manufactures for the repair/failure costs, recall expenses. In this paper, owing to the nature of the policy, we propose a new rate-making system considering the type of product and industry, quality control circumstances, record of guarantee performance, and exposures.

• Industrial Engineering and Management Systems
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• 제14권2호
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• pp.129-158
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• 2015

It is necessary for retailers to determine the optimal ordering policy of products considering supply disruptions due to a natural disaster and a production process failure as quality and machine breakdowns. Under the situation, a dualsourcing supply chain (DSSC) is one of effective SC for retailers to order products reliably. This paper proposes the optimal ordering policy of a product in a DSSC with a retailer and two manufacturers. Two manufacturers may face supply disruptions due to a natural disater and a production process failure after they received the retailer's order of products. Here, two scenarios of demand information of products are assumed: (i) the demand distribution is known (ii) mean and variance of the demand are known. Under above situations, two types of DSSC are discussed. Under a decentralized DSSC (DSC), a retailer determines the optimal ordering policy to maximize his/her total expected profit. Under the integrated DSSC (ISC), the optimal ordering policy is determined to maximize the whole system's total expected profit. Numerical analysis investigates how demand information and supply disruptions affect the optimal decisions under DSC and ISC. Besides, profitability of supply chain coordination adjusting the wholesale price is evaluated to encourage the optimal decision under ISC.