• 자동차안전학회지
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• 제4권2호
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• pp.17-21
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• 2012

The periodic technical vehicle inspection is to prevent the accident through the finding and fixing the defects of the vehicle. The periodic technical vehicle inspection in Korea was studied for assessing the adequacy of the inspection frequency. The inspection frequencies of many countries including EU, USA and Japan were compared. The average mileages by the vehicle usage and type were represented. The warranty period and recommended replacement period of parts of the domestic auto makers was studied. Currently, the inspection frequency for the periodic technical vehicle inspection in Korea is appropriate. The pass-fail rate and the cost-benefit analysis for the periodic technical inspection in Korea will be needed in the decision making process for the inspection frequency.

• 품질경영학회지
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• 제28권3호
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• pp.11-17
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• 2000

This paper presents a model for determining the optimal number of general repairs and supplementary input cost limit rate in addition to minimal repair cost rate to implement preventive maintenance. The basic concept parallels the periodic replacement model with minimal repair at failure introduced by Barlow and Hunter(1960) and Park(1979), only difference being the replacement signalled by the number of previous general repairs performed on the system. A general repair brings the state of the system to a certain better state than before repaired. Numerical examples are provided.

• 품질경영학회지
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• 제19권2호
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• pp.117-124
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• 1991

In this paper, it is assumed that a system is composed of an essential unit and a nonessential unit. During the running of the system, an essential unit is replaced at periodic replacement time T or at nth failure of essential unit whichever occurs first. Nonessential unit is replaced at its failure and at the replacement of essential unit. This paper derive optimal replacement period which minmises the total expected cost for replacement. The unimodality of totoal maintenance cost function is proved under the assumption that hazard rate of each component is continuous and monotone increasing failure rate(IFR). Based on this condition, it is shown that the optimal replacement period is finite and unique.

• Journal of the Korean Data and Information Science Society
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• 제22권4호
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• pp.775-784
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• 2011

본 논문에서는 비재생무료교체-수리보증이 종료된 이후의 수리가 가능한 시스템에 대한 주기적인 예방보전모형을 고려한다. 이러한 예방보전모형에 대하여 기대순환길이, 총기대비용 그리고 단위시간당 기대비용을 각각 유도하고자 한다. 또한 유도된 단위시간당 기대비용을 최소화하는 최적의 예방 보전주기와 예방보전횟수를 결정하는 방법에 대하여 자세히 설명한다. 끝으로 고장시간이 와이블분포를 따르는 경우에 최적의 주기적 예방보전정책을 결정하여 본다.

• 한국국방경영분석학회지
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• 제18권1호
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• pp.110-127
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• 1992

In the preventive replacement policies of system that the failure can be detected through only periodic inspection, there is a penalty cost associated with the lapsed time between system failure and its detection. The system under study is replaced if the system fails before $n^{th}$ inspection, otherwise, preventive replacement is performed at the $n^{th}$ inspection. The decision variables are the inspection interval and the period of preventive replacement. This study presents the optimal preventive replacement policy that minimizes the long-run expected cost per unit time.

• 품질경영학회지
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• 제22권3호
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• pp.54-65
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• 1994

A hybrid warranty policy for a repairable item is considered. Assuming that minimal repairs ar e performed for failures during warranty period, present worth of warranty cost is derived from a supplier's viewpoint. An optimal preventive periodic replacement policy for the case is also derived from a user's viewpoint Numerical examples are presented in order to explain the results.

• 한국군사과학기술학회지
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• 제4권1호
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• pp.170-176
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• 2001

An optimization problem to obtain the optimal replacement interval considering the salvage values is studied. The system is minimally repaired at failure and is replaced by new one at age T(periodic replacement policy with minimal repair of Barlow and Hunter〔2〕). Our model assumes that the time horizon associated with the number of replacements is random The total expected cost considering the salvage values with random time horizon is obtained and the optimal replacement interval minimizing the cost is found by numerical methods. Comparisons between non-considered salvage values and this case are made by a numerical example.

• 산업공학
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• 제15권1호
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• pp.89-98
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• 2002

This paper considers the optimum replacement times of a steam generator in nuclear power plant with failure data. It is assumed that the failure pattern of units is given as a Weibull distribution and repair and periodic preventive maintenance are performed periodically. The maximum likelihood method is used to estimated the Weibull parameters of failure distribution from failure data. Relpacement, output-decresing and maintenance costs are considered to determine the optimal replacement times by simulation. Numerical examples are included with actual failure data and cost estimators.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.352-364
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• 2007

It is essential to reduce track maintenance costs and to extend the periodic replacements of continuous welded rails based on accumulated passing tonnage. As recently train load decrease and rail joints wear down less, the periodic replacements of continuous welded rails can be extended. There are many kinds of rail damage like squat, head-check and corrugation. These can be taken nondestructive or naked eye test. So the periodic replacements of continuous welded rails based on accumulated passing tonnage were examine with focusing on a crack of rail bottom of continuous welded rail. Therefore, this study measure dynamic response of track by metro train load, it compute impact coefficient and track spring coefficient for estimating a condition of actual track system. Also, it is converted the measured stress waveform into stress frequency histogram by the rain-flow counting methods, and then the equivalence of stress is calculated. As apply s-n curve of a new welded rail, accumulated fatigue damage ratio of laid rail and remaining service lives is estimated. This study suggest a plan of the periodic replacements of continuous welded rails based on accumulated passing tonnage classified by the types of track system.

• 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.