• 산업경영시스템학회지
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• 제20권44호
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• pp.263-271
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• 1997

This paper presents a preventive maintenance model for determining the preventive replacement period of a system in which a failure rate is affected by the cumulative damage of fault and inspection. Especially, the failure rate function is considered to be a function of the cumulative damage of the fault and inspection time. Types of replacement considered are preventive replacement and failure replacement. Failure rate and expected cost function between replacement are derived. An optimal policy is obtained that minimizes the average cost per unit time for preventive replacement, failure replacement, inspection and repair.

• 품질경영학회지
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• 제30권3호
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• pp.53-65
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• 2002

This paper studies an economic manufacturing quantity (EMQ) model with two types of failures and planned preventive maintenance of the production facility. One is a type I (major) failure which should be corrected by a failure maintenance and the other is a type H (minor) failure which can be minimally repaired without interrupting the production run. The objective is to determine the lot size and preventive replacement policy minimizing the long-run expected cost per unit time. We consider a control policy with a constant production lot size and preventive maintenance after completing n production runs. It is assumed that both preventive and failure maintenance times are random and the demand arriving during a stock-out period is lost. An expression for the expected cost per unit time is obtained in the general case. A special case is discussed and numerical results are provided.

• 한국신뢰성학회지:신뢰성응용연구
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• 제6권2호
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• pp.151-161
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• 2006

This article is concerned with cost analysis model in periodic maintenance policy. The repair policy is differently applied according as unit importance during an item being used and unit restoration during an item being failed. So in this paper 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 spare unit until the periodic maintenance time arrived. Then total expected cost per unit time is calculated according to scale parameter of failure distribution in a view of customer's. The total expected costs are included repair and usage cost : operating, fixed, minimal repair, periodic maintenance and spare unit cost. Numerical example is shown in which failure time of item has Erlang distribution.

• 대한안전경영과학회지
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• 제6권1호
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• pp.61-70
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• 2004

In this paper, a group replacement policy based on a failure count is analysed. For a group of identical repairable units, a maintenance policy is performed with two phase considerations: a repair interval phase and a waiting interval phase. Each unit undergoes minimal repair at failure during the repair interval. Beyond the interval, no repair is made until a number of failures. The expected cost rate expressions under the policy is derived. A method to obtain the optimal values of decision variables are explored. Numerical examples are given to demonstrate the results.

• 한국콘텐츠학회논문지
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• 제18권12호
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• pp.456-467
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• 2018

본 연구는 양양국제공항 사례를 중심으로 정책실패의 반복 원인에 대하여 분석하였다. 2002년 개항한 양양국제공항은 약 3,600억원을 들여 건설하였으나, 공항 이용 객수 확보 실패 및 활성화 실패로 지방공항의 대표적 실패사례로 거론되고 있다. 정책실패 이론에 따라 합리주의적 관점, 정치적 관점, 환경복잡성 관점에 따라 양양국제공항의 실패요인을 분석한 결과 첫째, 합리주의적 관점에서 양양공항은 이용객 확보와 지역경제 활성화라는 정책목표 달성에 실패하였으며, 이는 정치권의 압력에 의한 사업추진과 지리적 인프라 부족에 기인한 것으로 나타났다. 둘째, 정치의 흐름에서의 이해관계자들의 갈등 조정 실패 양상은 항공사와 공항 간 갈등과 저가항공인 플라이양양 허가 및 지원금에 대한 정부와 공항 간의 갈등 조정 실패로 볼 수 있다. 셋째, 환경복잡성 관점에서 양양국제공항은 주변 고속도로, 철도 노선 개통과 한한령으로 인한 중국인 관광객 급감이라는 환경변화에 적응 실패로 볼 수 있다. 즉, 양양국제공항은 정책계획단계에서부터 합리적인 분석에 의해 무산된 사업임에도 불구하고 정치적으로 선거결과에 따라 지리적 인프라가 부족한 지역에 건설되었으며 운영 과정에서 항공사 및 정부 간의 갈등 조정에 실패하였고, 주변 교통시설 확충과 외부 환경적 요인에 적응하지 못한 것으로 볼 수 있다. 본 연구를 통해, 대규모 국책사업의 경우 정책결정자의 무리한 사업 추진을 막을 수 있는 독립적 기구의 설치, 공항이나 철도와 같은 교통시설의 경우 주변 인프라 및 관련 사업과의 연계 및 고려를 통한 사업 추진, 이해관계자들 간의 갈등조정을 위한 협력적 거버넌스의 제도화 등을 제언하였다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권4호
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• pp.280-286
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• 2016

Purpose: Recently, Jiang defines the tradeoff B life to minimize a sum of life lost by preventive maintenance (PM) and corrective maintenance (CM) contribution parts and sets up an optimal replacement age of age replacement policy as this tradeoff life. In this paper, Jiang's model only considering the known lifetime distribution is extended by assigning different weights to two parts of PM and CM in order to reflect the practical maintenance situations in application. Methods: The new age replacement model is formulated and the meaning of a weight factor is expressed with the implied cost of failure under asymptotic expected cost model and also discussed with one-cycle expected cost criterion. Results: The proposed model is applied to Weibull and lognormal lifetime distributions and optimum PM replacement ages are derived with corresponding implied cost of failure. Conclusion: The new age replacement policy to escape the estimation of cost of failure in classical asymptotic expected cost criterion based on the renewal process is provided.

• 산업경영시스템학회지
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• 제20권43호
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• pp.241-247
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• 1997

This paper is concerned with cost analysis model in free-replacement policy. The free-replacement policy with minimal repair is considered as follows; in a manufacturer's view point operating unit is periodically replaced, if a failure occurs between minimal repair and periodic maintenance time, unit is remained in a failure condition. Also unit undergoes minimal repair at failures in minimal-repair interval. Then total expected cost is calculated according to the parameter of failure distribution in a view of consumer's. The expected costs are included repair cost and usage cost: operating, fixed, minimal repair and loss cost. Numerical example is shown in which failure time of item has weibull distribution.

• 산업경영시스템학회지
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• 제19권39호
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• pp.89-98
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• 1996

This paper is concerned with cost analysis model in free -replacement policy under the periodic maintenance policy The free-replacement policy with minimal repairable item is considered as follows; in a manufacturer's view point operating unit is periodically replaced, if a failure occurs between minimal repair and periodic maintenance time, unit is remained in a failure condition. Also unit undergoes minimal repair at failures in minimal-repair interval. Then total expected cost per unit time is calculated according to maintenance period Tin a viewpoint of consumer's. The expected costs are included repair cost and usage cost: operating, fixed, minimal repair and loss cost. Numerical example is shown in which failure time of item has beta distribution.

• 산업경영시스템학회지
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• 제24권62호
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• pp.1-10
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• 2001

The electronics industry is fast growing segment of manufacturing and service industries. It is important that the manufacturer develops a product with adequate life cycle, high quality, and low failure rate in the specified time period. Environmental Stress Screening(ESS) and burn-in are widely used in the electronic industry to assist in the elimination of early failure. In this research, we construct optimal cost model of combined ESS and burn-in under various warranty policy and establish optimal testing times for given environments. Also we conduct sensitivity analysis on various parameter. The results of this study are summarized as follows. Comparing free warranty policy to rebate warranty policy, optimal ESS time is longer under free warranty policy, and optimal burn-in time is longer under rebate warranty policy. Free warranty policy higher than rebate warranty policy in total cost.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2005년도 학술발표대회 논문집
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• pp.115-120
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• 2005

This paper introduces models for preventive maintenance policies and considers periodic preventive maintenance policy with minimal repair when the failure of system occurs. It is assumed that minimal repairs do not change the failure rate of the system. The failure rate under prevention maintenance received an effect by a previously prevention maintenance and the slope of failure rate increases the model where it considered. Also the start point of failure rate under prevention maintenance considers the degradation of system and that it increases quotient, it assumed. Per unit time it bought an expectation cost from under this prevention maintenance policy. We obtain the optimal period time and the number for the periodic preventive maintenance by using Nakagawa's Algorithm, which minimizes the expected cost rate per unit time. Finally, it suppose that the failure time of a system has a Weibull distribution as an example and we obtain an expected cost rate per unit time the optimal period time and the number when cost of replacement and cost of minimal repair change.