• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.22-24
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• 2006

The installations of power quality monitoring system have increased drastically over the past several decades. These systems have been effectively used to monitor, analyze and diagnose the conditions of power system, and furthermore can be used to improve the present asset maintenance policy, scheduled (time-based) method, into the advanced, cost-effective and labor-effective maintenance methods, such as condition-based maintenance, predictive maintenance and reliability centered maintenance. As an approach to this, this paper introduces the statistical methods, three kinds of control charts (Shewhart chart, CUSUM chart and EWMA chart), and discusses the applicability of these methods to recognize the changing trends of power quality indices and to estimate the system's condition, using Matlab.

• 품질경영학회지
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• 제25권1호
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• pp.31-43
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• 1997

In this study, the pros and cons of TPM and RCM were comparatively evaluated at various aspects : a, pp.ication process, objectives, maintenance items, organizations, analysis of maintenace methods, etc. It is found that TPM can be considered as a management discipline. However, in TPM, there seldom exist concrete rules or guidelines to select a maintenance scheme. RCM, which is a widely used maintenance scheme for aircrafts or power plants, has a good analysis and decision logic for maintenance planning. In the paper, similar decision rules are adopted to TPM deployment to get an effective and effecient maintenance Planning.

• 한국산림과학회지
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• 제66권1호
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• pp.8-15
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• 1984

인구(人口)의 도시집중(都市集中)에 의(依)해 급격히 증가(增加)하고 있는 아파트단지(團地)의 조경수목(造景樹木)에 대(對)한 관리(管理)는 쾌적(快適)한 주거환경(住居環境)의 제공(提供)이라는 면(面)에서 중요(重要)한 의미(意味)를 지니고 있다. 주거환경(住居環境)의 질(質)을 높이는 데 중요(重要)한 역할(役割)을 담당하고 있는 조경수목(造景樹木)은 그동안 관리부실(管理不實)로 인(因)해 생육(生育)이 불량(不良)하고, 높은 하자율(瑕疵率)을 나타내었다. 이러한 현실(現實)에 대(對)한 개선방법(改善方法)으로는 식재공사(植栽工事)의 하자발생(瑕疵發生)을 최소(最少)로 하기 위한 시공기술(施工技術)의 향상(向上)과 이론적(理論的) 연구(硏究)가 필요(必要)하며, 조경부문관리인(造景尃門管理人)을 두어 관리기능(管理機能)을 강화(强化)함과 동시(同時)에 제도상(制度上) 적정수준(適正水準)의 관리비(管理費) 항목(項目)이 설정(設定)되어야 하며, 높은 주민(住民)의 관리의식(管理意識)을 바탕으로 관리(管理)에 대한 자발적(自發的)인 참여(參與)를 유도(誘導)할 수 있는 분위기(雰圍氣)를 조성(造成)하는 것이라 하겠다.

• 대한전기학회논문지:전력기술부문A
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• 제48권5호
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• pp.545-552
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• 1999

The Maintenance scheduling is one of the mid-term scheduling problems systems. There have been many methods for this problem, but there is no effective way to treat all the generators simultaneously. In this paper, we apply a genetic algorithm(GA) to the maintenance scheduling problem. We proposed new crossover operators(BOX type crossover) to improve searching ability of GA. Satisfactory results are obtained by GA with the proposed corssover operators.

• 한국도로학회논문집
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• 제15권5호
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• pp.91-99
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• 2013

PURPOSES : This study aims at proposing the methodology for benefit evaluations in pavement maintenance methods and timings using KoPMS(Korean Pavement Management System) software which was developed for efficient pavement management. METHODS : This study classified pavement sections into 4 clusters considering AADT(Annual Average Daily Traffic) and ESAL(Equivalent Single-Axle Load) using cluster analysis and used the deterioration models in each cluster. Increased user costs due to pavement deterioration as time goes by and agent costs for maintenance were estimated. Based on deterioration model and KoPMS software, Methodology for benefit evaluation was proposed in pavement maintenance methods and with/without implementation using real pavement section data. RESULTS : This study verified that considering agent costs only would be constrained to decide pavement maintenance methods and timings, and ascertained that decision making with agent and user costs would be effective. In addition, this study revealed that pavement maintenance methods and timings can be affected by AADT and ESAL and frequent pavement maintenances can be more efficient for benefits in pavement sections with more AADT and ESAL. Also this study found that user costs would be more affected to decision making than agent costs. Moreover, Delay of conducting pavement maintenance caused increased vehicle operating costs and environmental costs because of poor conditions of pavements. CONCLUSIONS : This study proposed LCCA and benefit estimation methodology of pavement with considering agent and user costs. The results of this study can be used for baseline data of efficient pavement asset management.

• 교육시설
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• 제23권2호
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• pp.19-21
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• 2016

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.332-334
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• 1998

Maintenance scheduling is one of mid-term scheduling problems of power systems. There have been many methods for this problem, but there is no effective way to treat all the generators simultaneously except evolutionary algorithms. In this paper, we apply GA to the maintenance scheduling problem. And we proposed new crossover operator(BOX type crossover) to improve searching ability of GA. Satisfactory results are obtained by GA with proposed crossover operator.

• Nuclear Engineering and Technology
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• 제46권6호
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• pp.737-752
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• 2014

As condition-based maintenance (CBM) has risen as a new trend, there has been an active movement to apply information technology for effective implementation of CBM in power plants. This motivation is widespread in operations and maintenance, including monitoring, diagnosis, prognosis, and decision-making on asset management. Thermal efficiency analysis in nuclear power plants (NPPs) is a longstanding concern being updated with new methodologies in an advanced IT environment. It is also a prominent way to differentiate competitiveness in terms of operations and maintenance costs. Although thermal performance tests implemented using industrial codes and standards can provide officially trustworthy results, they are essentially resource-consuming and maybe even a hind-sighted technique rather than a foresighted one, considering their periodicity. Therefore, if more accurate performance monitoring can be achieved using advanced data analysis techniques, we can expect more optimized operations and maintenance. This paper proposes a framework and describes associated methodologies for in-situ thermal performance analysis, which differs from conventional performance monitoring. The methodologies are effective for monitoring, diagnosis, and prognosis in pursuit of CBM. Our enabling techniques cover the intelligent removal of random and systematic errors, deviation detection between a best condition and a currently measured condition, degradation diagnosis using a structured knowledge base, and prognosis for decision-making about maintenance tasks. We also discuss how our new methods can be incorporated with existing performance tests. We provide guidance and directions for developers and end-users interested in in-situ thermal performance management, particularly in NPPs with large steam turbines.

• 대한산업공학회지
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• 제33권1호
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• pp.61-69
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• 2007

In a large complex system, maintenance priorities for the failed components are important to maintain the sys-tern reliability at required level. Commonly used methods of determining maintenance priorities are based onranking the failed components by using reliability importance measures such as Birnbaum reliability importance,risk achievement worth and F-V importance, etc. In the preceding works, maintenance priorities for the failedcomponents are determined by using such existing measures, In this study, a new method of determining main-tenance priorities, which utilizes the joint reliability importance is proposed. By investigating the sign of thejoint reliability importance, maintenance priorities obtained by the existing methods are adjusted to yield new re-vised priorities. The revised maintenance priorities are shown to be more effective than the existing ones fromthe standpoint of the speed of system recovery, Effectiveness of the proposed method is illustrated by numericalexamples.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1481-1498
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• 2007

As railroad industry face the new Renaissance era, effective and efficient maintenance methods for rolling stock operation are required with advanced railroad technology. All kinds of railroad systems such as high speed long distance train, metropolitan mass transit and light rail require systematic maintenance technology in order to maintain the safe railroad operation. Simulation models for detailed operations of the sample maintenance center are developed. In this study, standard maintenance procedures, layout, equipments and number of workers of Siheung Metropolitan Railroad Maintenance Rolling Stock Depot are considered. The proposed simulation models are developed using simulation package ARENA. Three simulation analysis using the developed simulation model are done. First, the bottleneck operation is identified. Second, the relationship between maintenance center size, number of workers and cycle time is analyzed. Lastly, the scheduling performances between PERT/CPM and Critical Chain Project Management(CCPM) are compared.