• 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.

• 품질경영학회지
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• 제31권3호
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• pp.185-192
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• 2003

In this paper, the properties on the optimal replacement policies for the general failure model are developed. In the general failure model, two types of system failures may occur : one is Type I failure (minor failure) which can be removed by a minimal repair and the other, Type II failure (catastrophic failure) which can be removed only by complete repair. It is assumed that, when the unit fails, Type I failure occurs with probability 1-p and Type II failure occurs with probability p, $0\leqp\leq1$. Under the model, the system is minimally repaired for each Type I failure, and it is repaired completely at the time of the Type II failure or at its age T, whichever occurs first. We further assume that the repair times are non-negligible. It is assumed that the minimal repair times in a renewal cycle consist of a strictly increasing geometric process. Under this model, we study the properties on the optimal replacement policy minimizing the long-run average cost per unit time.

• 품질경영학회지
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• 제39권4호
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• pp.480-485
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• 2011

This paper presents a spare ordering policy for preventive replacement with minimal repair. To analyze the ordering policy, the failure process is modeled by a non-homogeneous Poisson process. Introducing the ordering, repair, downtime, replacement costs and salvage value, we derive the expected cost effectiveness as a criterion of optimality when the lifetime and lead times for the regular and expedited orders are generally distributed random variables. It is shown that, under certain conditions, there exists a finite and unique optimum ordering time which maximizes the expected cost effectiveness. A numerical example is also included to explain the proposed model.

• 대한산업공학회지
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• 제32권2호
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• pp.141-152
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• 2006

This paper presents the development of a decision model to examine the optimal repair action for a deteriorating system. In order to make a reasonable decision, it is necessary to perform an analysis of the uncertainties embedded in deterioration and to evaluate the repair actions based on the expected future cost. Focusing on the power law failure model, the uncertainties related to deterioration are analyzed based on the Bayesian approach. In addition, we develop a decision model for the optimal repair action by applying a repair cost function. A case study is given to illustrate a decision-making process by analyzing the loss incurred due to deterioration.

• 경영과학
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• 제26권1호
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• pp.209-223
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• 2009

In this paper, an analysis problem of repair levels and spare part allocation for MIME(Multi indenture multi echelon) systems is studied using simulation and meta-heuristics. We suggest a method to determine simultaneously repair levels and spare parts allocation to minimize the life cycle cost of MIME system under availability constraint. A simulated annealing method is used to analyze the repair levels and genetic algorithm is used to obtain the optimal allocation of spare parts. We also develop a simulation system to calculate the life cycle cost and system availability. Some numerical examples are also studied.

• 한국철도학회논문집
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• 제8권3호
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• pp.260-266
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• 2005

The deterioration of a shunting locomotive was characterized for the lifetime assessment. The locomotive has been used for shunting works in steel making processes, and in this investigation, various types of technical evaluation methods for the locomotive parts were employed to assess the current deterioration status and to provide important clue for lifetime prediction. Unlike other rolling stocks in railway applications, the diesel shunting locomotive is composed of major components such as diesel engine, transmission, gear box, brake system, electronic devices, etc., which cover more than 70 percent of the total price of the locomotive. Therefore, in this paper, each part of major components in the diesel locomotive was analyzed in terms of the degree of deterioration. The lift-cycle-cost (LCC) analysis was performed based on the maintenance and repair history as compared with economical cost to provide the cost-effective prediction, i.e., to assess either repair for reuse or putting the locomotive out of service based on cost-effective calculation.

• 한국산학기술학회논문지
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• 제17권11호
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• pp.128-134
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• 2016

교량관리시스템(Bridge Management System, BMS)을 활용한 교량의 생애주기 관리를 위해서는 교량의 부재별 보수보강 비용 산정이 필수적이다. 본 연구에서는 BMS에 적용 가능한 체계적인 유지관리 비용 모델의 개발을 위하여 교량을 구성하는 대표 부재를 정의하고, 대표 부재별 세부 및 대표 보수보강 공법을 도출하였다. 세부 보수보강 공법별 단가를 산정하기 위해 표준 품셈과 실적 공사비를 이용해 각 세부 보수보강 공법별 일위대가를 구성하고, 적산 프로그램을 활용하여 보수보강 단가의 갱신이 용이하도록 체계적인 절차를 제시하였다. 또한 세부 보수보강 공법별 단가와 적용 빈도를 고려해 가중 평균 형태로 대표 보수보강 공법의 평균 단가를 산정하였다. 도출된 평균 단가를 기존의 실적 비용 단가와 비교 검증하여 적정성을 검토하였다. 제안된 평균 보수보강 비용 단가는 교량 유지관리 계획 수립 단계에서 요구 예산의 타당성을 검증하거나 보수보강 실적 비용의 적정성을 검토하는 데 활용될 수 있다. 본 연구를 통해 유지관리 비용 정보의 신뢰도와 의사결정의 합리성을 증진시킬 수 있을 것으로 판단된다.

• 한국자동차공학회논문집
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• 제13권2호
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• pp.157-161
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• 2005

In the FY 2003, the number of registered vehicles in Korea reached 14 million, which is 7.7% increase from the previous year. The increase of number of vehicles has caused a lot of social problem with enormous costs. The social costs related to the vehicles includes environmental costs resulting from pollution and scraping of vehicles, those resulting from life-saving and repairing from car accidents and so on. There have been m any efforts to reduce the social costs in m any areas. As a part of the efforts, there are recent grow ing interests on the damageability & repairability in related industries. In this study, we investigated the cases of two different types of bum per stay. Futhermore, we analyzed their effects on damageability & repairability and reduction of repair cost. So we found that if the manufacturers design new cars with good damageability & repairability, then the total repair cost in crash will be reduced.

• 농촌계획
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• 제18권3호
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• pp.67-76
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• 2012

The purpose of this study is to analyze the landscape preference and landscape images of the Agricultural Aqueduct Bridges(AAB) by several different criteria. Semantic Differential Scale(SD scale) with landscape adjectives and landscape preference are used to estimate the alternatives of the AAB. The statistic methods such as descriptive analysis, t-test, factor analysis and regression, cluster analysis, are operated. The landscape preference of the alternatives is generally positive, 3.977 out of 7.000. The gate type is the most preferred, but the road-along type is the worst, by the location types. The simple repair type is the worst preferred, but total remodeling is the most, by the repair types. The characteristics of the AAB are analyzed and 4 factors of visual landscape are contracted; interest, orderliness, naturality and spatiality. Cumulative factor loading of these factors is about 65%, which is quite high. The higher and bigger AAB's are preferred, and the advanced finishing materials are also preferred, such as aluminum or wood panels. The long span is also preferred and the high repair cost would be preferred. But in this study, the cost-benefit analysis is not included, so it is recommended to research further, considering the cost variable with the visual factors.

• 자동차안전학회지
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• 제13권3호
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• pp.69-77
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• 2021

Although accident data from the National Police Agency and insurance companies do not know the vehicle safety, the damage level information can be obtained from the data managed by the bus credit association or the bus company itself. So the accident severity was analyzed based on the side impact accidents using accident repair cost. K-means clustering analysis separated the cost of accident repair into 'minor', 'moderate', 'severe', and 'very severe'. In addition, the side impact accident severity was analyzed by using an ordered logit model. As a result, it is appeared that the longer the repair period, the greater the impact on the severity of the side impact accident. Also, it is appeared that the higher the number of collision points, the greater the impact on the severity of the side impact accident. In addition, oblique collisions of the angle of impact were derived to affect the severity of the accident less than right angle collisions. Finally, the absence of opponent vehicle and large commercial vehicles involved accidents were shown to have less impact on the side impact accident severity than passenger cars.