• Title, Summary, Keyword: Imperfect Maintenance

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Quasi-renewal 이론을 이용한 발전설비의 불완전한 유지보수 예방정비 계획 (Imperfect Preventive Maintenance Plan of Generation Unit Using Quasi-renewal Theory)

  • 김형준;변융태;김진오;이준경
    • 전기학회논문지
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    • v.57 no.5
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    • pp.735-740
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    • 2008
  • Recently, the research of PM (Preventive Maintenance) method on the RCM(Reliability-Centered Maintenance) of the system equipment is being actively advanced for a few years. For the most of the current power equipment maintenance, the state of the equipment after maintenance is assumed to be becoming 'as good as new ones' state. However, the state of the power equipment is maintained like the states of the between 'as good as new ones' and 'as bad as old ones' by imperfect maintenance that implies the life decrease of the equipment by frequent breakdown, the error of maintenance process, and so on. So, the Maintenance method considering the real case has to reflect Imperfect maintenance than perfect maintenance. This paper suggests the Preventive Maintenance method by using Quasi - Renewal Theory for the gas turbine equipment as deliberating the imperfect maintenance for the real cases.

An Introductory Study on Imperfect Maintenance Effect in Rolling Stocks

  • Kim, Jong-Woon;Han, Seok-Yun;Chung, Jong-Duk
    • International Journal of Railway
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    • v.1 no.2
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    • pp.59-63
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    • 2008
  • The maintenance effect is a peculiar factor applied to repairable systems such as rolling stocks. Conventional statistical analysis for failure times takes into account one of the two following extreme assumptions, namely, the state of the system after maintenance is either as "good as new" (GAN, perfect maintenance model) or as "bad as old" (BAO, minimal maintenance model). Most of the papers concerning the stochastic behavior of railroad systems assume two types of maintenance: perfect and minimal maintenance. However, Lee, Kim & Lee (2008) analyzed the failure data of a door system in Metro EMU and the effect of preventive maintenance was imperfect. It is seen that the imperfect maintenance is of great significance in practice. This article describes how to deal with the maintenance effect in reliability studies of rolling stocks. Maintenance policies under imperfect maintenance are described and the method is proposed to evaluate their performance.

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불완전 보전모형의 특성에 관한 연구 (A Study on the Characteristics of the Imperfect Maintenance Models)

  • 이진식;유정모
    • 산업공학
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    • v.14 no.3
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    • pp.272-285
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    • 2001
  • Proper maintenance techniques have been emphasized in recent years due to increased safety and reliability requirements of systems, increased complexity, and rising costs of material and labor. In the related literature, most studies assume that the system after cm or pm is 'as good as new'(perfect maintenance) or 'as bad as old'(minimal maintenance). But many maintenance activities may not result in these two extreme situations but in a complicated intermediate one. Therefore, perfect maintenance and minimal maintenance are not practical in many actual instances and so realistic imperfect maintenance should be modeled. For this study, various imperfect preventive maintenance models are investigated and analyzed. From the analysis of the imperfect maintenance models modeling methods and maintenance policies are arranged and presented some tables providing informations to the maintenance managers.

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불안전한 유지보수를 고려한 전력 설비의 예방 정비 계획 (Preventive Maintenance Plan of Power System Unit Considering Imperfect Maintenance)

  • 변융태;김형준;김진오;김형철
    • 대한전기학회:학술대회논문집
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    • pp.328-330
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    • 2007
  • Recently, the research of PM (Preventive Maintenance) method on the RCM(Reliability-Centered Maintenance) of the system equipment is being actively advanced for a few years. The state of the power equipment is maintained like the states of the between 'as good as new ones' and 'as bad as old ones' by imperfect Maintenance that implies the life decrease of the equipment by frequent breakdown, the error of maintenance process, and so on. So, the Maintenance method considering the real case has to reflect Imperfect maintenance than perfect maintenance. This paper suggests the Preventive Maintenance method by using Quasi - Renewal Theory for the gas turbine equipment as deliberating the imperfect maintenance for the real cases.

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시뮬레이션을 통한 불완전 유지보수하에서의 유지보수 정책의 효율성 평가에 관한 사례 연구 (A case study on evaluating the effectiveness of maintenance policies under imperfect maintenance)

  • 이덕규;이희성
    • 한국철도학회:학술대회논문집
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    • pp.1539-1544
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    • 2008
  • 기존 연구에서 도어시스템에 대한 중정비가 완전 유지보수가 아닌 불완전 유지보수인 사례가 발표되었다. 불완전 유지보수인 경우에는 유지보수 효과를 고려하여 적절한 유지보수 정책을 수립하여야만 시스템의 신뢰성을 확보하면서 경제적인 유지보수를 수행할 수 있다. 본 연구에서는 전동차량의 승객용도어 시스템(passenger door system:PDS)을 대상으로 중정비의 효과가 불완전할 경우 고려할 수 있는 유지보수 정책의 효율성을 시뮬레이션을 통해 평가함으로써 유지보수 정책을 결정하는데 도움을 주고자 한다.

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예방보전이 불완전할 때 최적 주기적 예방보전 계획 (Optimal Periodic Preventive Maintenance Schedule When Preventive Maintenance is Imperfect)

  • 김대경;신상욱;임재학
    • 품질경영학회지
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    • v.35 no.4
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    • pp.140-146
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    • 2007
  • In this paper, we consider a periodic imperfect preventive maintenance(PM) policy in which the system's failure rate after each PM remains unchanged. The system undergoes only minimal repairs at failures between PMs. Exact mathematical formula of the expected cost rate per unit time is derived. Optimal number of PMs and optimal maintenance period are derived by minimizing the expected cost rate per unit time. A numerical example is provided to illustrate the proposed approach under Weibull lifetime distribution.

불완전 유지보수 모형을 통한 전동차 도어장치 예방 유지보수 주기 산정에 관한 연구 (A study on determining imperfect preventive maintenance intervals for the doors in Metro EMU)

  • 이덕규;김종운;이희성
    • 한국철도학회:학술대회논문집
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    • pp.733-741
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    • 2008
  • An important problem in reliability analysis for repairable systems is to model the maintenance effect. The most of researches have assumed two extreme cases; one is perfect maintenance and the other is minimal maintenance. However, there are many cases in real situations that the maintenance effect are between both of two extreme cases. This article deals with the problem determining the imperfect preventive maintenance intervals for the doors in Metro EMU

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불완전보전을 고려한 시스템의 최적 정기 예방보전 시기 (Optimum Periodic Preventive Maintenance Time for a System with Imperfect Maintenance)

  • 정영배
    • 산업경영시스템학회지
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    • v.17 no.32
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    • pp.221-226
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    • 1994
  • Almost preventive maintenance policies assumed that the system after pm has failure rate as before pm with probability p and as good as new with probability 1-p. This paper considers the s-expected cost of the model with imperfect periodic preventive maintenance that increasing minimal repair costs at failure and obtains the optimum periodic preventive maintenance time. Numerical example are shown in which the failure time of the system has gamma distribution.

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전동차 승객용도어시스템의 유지보수 효과를 고려한 유지보수 주기 산정에 관한 연구 (A study on Determining Maintenance Intervals Considering the Maintenance Effect for the PDS in Metro EMU)

  • 이덕규;손영진;이희성
    • 한국철도학회논문집
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    • v.14 no.3
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    • pp.216-221
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    • 2011
  • 수리 가능한 시스템의 신뢰성 분석에 중요한 문제 중의 하나는 유지보수 효과를 모델링하는 것이다. 현재까지 많은 연구들은 유지보수 후 시스템의 상태가 새것과 같이 된다는 완전유지보수 또는 유지보수 바로 직전의 상태로 된다는 최소유지보수 모형을 사용하였다. 그러나 국내운영기관에서 시행하는 유지보수 형태는 완전유지보수와 최소유지보수의 사이의 효과를 가지는 불완전유지보수 형태로 시행하는 경우가 많다. 본 연구에서는 이와 같이 불완전 유지보수가 수행되는 전동차의 장치들 중에서 승객용 도어시스템(PDS:passenger door system)의 고장데이터를 분석하고 유지보수 효과 수준을 적용하여 불완전유지보수 주기를 결정하는 문제를 다루었다.

Some Stochastic Properties of Imperfect Repair Model with Random Repair Time

  • Kim, Dae-Kyung;Lim, Jae-Hak
    • International Journal of Reliability and Applications
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    • v.4 no.1
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    • pp.27-40
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    • 2003
  • Maintenance models involving minimal imperfect repair frequently appear in the literature of reliability and operations research. Most of the literatures concerning the stochastic behavior of repairable systems assume that it takes negligible time to repair a failed system and so the length of repair time does not affect the maintenance strategy. It is more realistic to consider the length of repair times in developing maintenance model, however. In this paper, we consider an imperfect repair model with random repair time and investigate some stochastic properties of the number of perfect repairs and the number of minimal repairs. Also we derive the expressions for evaluating the expected numbers of perfect and minimal repairs in general and apply these formulas for certain parametric life distributions.

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