• 한국경영과학회지
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• 제27권2호
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• pp.33-49
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• 2002

CBM (Condition-Based Maintenance) has increasingly drawn attention in industry because of its many benefits. CBM Problem Is characterized as a state-dependent scheduling model that demands simultaneous maintenance actions, each for an attribute that influences on machine condition. This problem is very hard to solve within conventional Markov decision process framework. In this paper, we present an intelligent machine maintenance scheduler, for which a new incremental decision tree learning method as evolutionary system identification model and shortest path problem as schedule generation model are developed. Although our approach does not guarantee an optimal scheduling policy in mathematical viewpoint, we verified through simulation based experiment that the intelligent scheduler is capable of providing good scheduling policy that can be used in practice.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1359-1370
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• 2008

In the track geometry such as rails, sleepers, ballasts and fastener, track deterioration occurs by repetitive train weight and the high-speed railway takes a trend faster than normal. Track deterioration of over threshold value harms ride comfort and furthermore affect in trains safety seriously. An organic and systematic track maintenance system is very important because a trend of the track deterioration effects on track life-cycle and running safety. Also costs of the railway track permanent way and its maintenance are extremely large, forming a significant part of the total infrastructure expenditure. Therefor reasonable and efficient track maintenance has to be planed on a budget. It is required to carry out not only corrective maintenance but preventive maintenance for the track maintenance. In order to perform maintenance jobs in the boundary of the machines and resources given regarding the type and amount jobs, it is necessary to determine feasible or optimal scheduling considering the priority. In this study, the system organization and required functions for the development of track maintenance system supported track deterioration prediction and optimal scheduling are proposed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
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• pp.447-449
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• 2003

In competitive electricity markets, maintenance schedule is submitted by Genco's and Transco's, and coordinated by ISO with the adequacy criterion. This paper presents an alternative coordination procedure by ISO on the maintenance schedule.

• 전기학회논문지
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• 제57권8호
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• pp.1305-1310
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• 2008

Traditional maintenance planning is based on a constant maintenance interval for equipment life. In order to consider economic aspect for time based preventive maintenance, preventive maintenance is desirable to be scheduled by RCM(Reliability-Centered Maintenance) evaluation. The main objective of RCM is to reduce the maintenance cost, by focusing on the most important functions of the system and avoiding or removing maintenance actions that are not strictly necessary. So, Markov state model is utilized considering stochastic state in RCM. In this paper, a Markov state model which can be used for scheduling and optimization of maintenance is presented. The deterioration process of system condition is modeled by the stepwise Markov model in detail. Also, because the system is not continuously monitored, the inspection is considered. In case study, simulation results about RCM will be shown using the real historical data of combustion turbine generating unit in Korean power systems.

• 한국산학기술학회논문지
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• 제19권12호
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• pp.303-312
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• 2018

대학 시설은 다수의 건물들로 구성되어 많은 유지보수항목이 있고 한정된 기간 내에 처리해야 하는 관리상의 제약사항이 있다. 대부분의 유지보수 작업은 규모가 작으며 방수공사 등 다수 공종이 동시에 진행되는 특성을 가진다. 시설관리자는 유지보수업체와 연간단가계약을 맺고 공사를 추진하지만 기존 유지보수공사는 일정 및 인력투입계획 없이 공사가 진행되어 공사지연과 다수의 재작업이 발생하고 있다. 본 연구는 시설관리자가 다수의 대학 시설물 유지보수공사들을 프로그램 레벨로 관리할 수 있도록 지원하는 일정계획 모델을 제안하였다. 모델은 순차적으로 진행되는 3단계로 구성된다. 대상 분석단계에서는 수량산출서를 바탕으로 유지보수항목들의 세부공종을 분석하고 수량을 산출한다. 자원 분석단계에서는 효과적인 전문기능공의 투입을 위해 세부공종별 전문기능공 및 공사기간을 도출한다. 일정계획 수립단계에서는 공종별 우선순위와 최적 투입인력이 도출되고 적합도에 따라 일정계획 최적안을 선정한다. 사례적용결과 프로그램 레벨에서 다수 대학시설물 유지보수공사 간의 효과적인 인력투입이 가능하며, 노무비가 감소되어 모델 적용 전 보다 많은 수의 공사를 완료할 수 있었다. 실무자 면담을 통해 모델의 적용성 및 효과성을 평가한 결과 관리자의 유지관리공사 일정관리를 지원할 수 있는 효과적인 도구로 평가되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.798-800
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• 2005

In competitive electricity markets, the System Operator (SO) coordinates the overall maintenance schedules whenever the collective maintenance schedule reported to SO by Gencos & Transco in the pool does not satisfy the specified operating criteria, such as system reliability or supply adequacy. We propose a two-layer mathematical algorithm amenable to maintenance scheduling problem into master problem and sub-problem. The master problem coordinates the scheduling, and sub-problem, DC optimal power flew, checks the adequacy. The proposed algorithm was demonstrated with a case study.

• 한국철도학회논문집
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• 제13권6호
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• pp.601-607
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• 2010

본 논문의 목적은 보다 빠르고 수월하게 현장의 상황을 반영하여 NP-hard 철도 궤도 유지보수 일정계획을 최적화할 수 있는 Binary Artificial Bee Colony Algorithm (BABC) 휴리스틱 알고리즘을 제안하는 것이다. 본 논문에서 제시하는 방법을 사용하여 빠른 시간 또는 사용자가 제시하는 시간 내에 최적해 또는 최선 해를 제시할 수 있다. 본 논문에서 제안하는 방법을 사용하여 30, 60, 100, 200개 작업의 궤도 유지보수 일정계획 문제의 실험 및 분석을 통하여 목적식 값을 최대화할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.855-858
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• 1988

Two methods for probabilistic maintenance scheduling are developed and compared ; one with operation and supplied-shortage cost and other with risk level of LOLP. Based on the real economic power dispatch, quadratic optimal maintenance conditions are obtained and simple amtrix equations are suggested for solutions. Both methods are compared in a sample system of 26,000 [MW] peak and 32,000 [MW] generation capacity.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.559-561
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• 1995

The cogeneration system has a strong merit in providing thermal and electrical energy simultaneously. Nowadays, cogeneration system is widely used in the point of efficient use of the energy resources And the installation of the system is expected to be greatly increased in each year. So, we need to develop an optimal operation planning for those systems. In this paper, we are used to result what studed at the my power system of room because it is in order to solve maintenance scheduling problem. Also we added a constraints to the proposed maintenance model for optimal maintenance rate. In the case study, we construct an multi-machine generated example system which operated in topping cycle, and calculate the yearly optimal production cost, marginal maintenance cost, and maintenance scheduling of the example system respectively.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.312-317
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• 1998

Reliable maintenance scheduling of main equipments is a crucial problem in thermal power stations in order to skirt overall losses of power generation resulted from severe failures of the equipments. A reasonable method was proposed to determine the maintenance scheduling of whole pump system in thermal power stations in order to reduce the maintenance cost by keeping the present avail-ability of the pump system throughout the operation. The dimensional reduction method was used to solve problems encountered due to few data which involved many operational factors in failure rate of pumps. The problem of bandlimited nature of data with time was solved by extrapolating future failures from presently available actual data with an aid of Weibull distribution. The results of the analysis identified the most suitable maintenance intervals of each pump type accordingly and hence reduce the cost of unnecessary maintenance with an acceptable range in the overall system availability.