• 조명전기설비학회논문지
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• 제24권10호
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• pp.58-66
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• 2010

This paper shows an implementation and management result of wireless networks based security light control system, which performs a great role in protection of pedestrians and prevention of crime. Conventional security light units have severe limits in confirmation and inspection of security light unit failure, like wilful damage by someone or failure by influence of other equipment or failure by spontaneous heat-increase, and so on. In addition, local government offices are responsible for maintenance of security light units and as a matter of fact, most of civil complaints are about security light units. It is an obvious that the existing security light maintenance system reaches the limit and the security light maintenance problem is a difficulty of local government. Therefore, efficient security light control system is needed, which enables central control and intelligent maintenance. Moreover, the system has to be easy to control and has to be stable. In this study, wireless sensor network based security light control system is implemented, which is independent of programming language and platform, and which is simple to control and extend the system. The proven protocols, HTTP and SOAP, are utilized in order to improve the system reliability. This paper shows the excellence of our proposed system by implementing and operating it in real environment.

• Journal of the Korean Data and Information Science Society
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• 제21권1호
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• pp.109-119
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• 2010

고장보고분석 및 정비시스템은 군용장비를 주요 대상으로 신뢰성과 정비성을 개선하기 위해 사용 하는 관리도구이다. 고장보고분석 및 정비시스템은 고장, 결함 및 정비기록을 수집하고 그 원인을 분석하여 고장에 대한 대책 수립 과정에 적용함으로써 체계 및 서비스를 지속적으로 감시, 효율적으로 통제하는 폐쇄적 피드백 시스템으로 체계의 개발단계부터 운용 및 폐기까지의 수명주기 동안 해당 업무 담당자 및 고객에게 보고되어 고장대책에 대한 조치가 이루어지도록 하는 시스템이다. 또한, 향후 새로운 설계와 시스템 개발시 신뢰도를 성장시킬 수 있는 중요한 역할을 하는 시스템이다. 본 연구에서는 일반적인 군의 고장보고분석 및 정비시스템 개발과정을 검토하고 한국의 무기체계와 운용 및 정비 환경에 적합하게 구축된 고장보고분석 및 정비시스템에 대하여 알아본다.

• 품질경영학회지
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• 제35권4호
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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.

• 대한안전경영과학회지
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• 제16권3호
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• pp.209-218
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• 2014

An accident related with elevators can cause death or serious injury of operators or passengers. This kind of a fatal accident is due to a failure of elevator. The reduction of failures of elevators is important to reduce the occurrence of elevator accident. Thus, this paper presents the results of analysis for the failure of elevators using the failure data of elevator. The results of analysis can be used to make a maintenance process of elevators.

• 전기학회논문지
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• 제62권6호
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• pp.870-875
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• 2013

After introducing diagnosis equipment power failure prevention activities for distribution system have become more active. To do facility diagnosis and maintenance work more efficiently we need to evaluate reliability for the system and should determine the priority line with appropriate criteria. Thus, to calculate risk factor for the power distribution line that are composed of many component facilities its historical failure events for the last 5 years are collected and analysed. The failure statics show that more than 60% of various failures are related to environment factors randomly and about 20% of the failures are refer to the aging. As a strategic evaluation system reflecting these environmental influence is needed, a system on the basis of the probabilistic approach related statical variables in terms of failure rate and failure probability of electrical components is proposed. The figures for the evaluation are derived from the field failure DB. With adopting Bayesian rule we can calculate easily about conditional probability query. The proposed evaluation system is demonstrated with model system and the calculated indices representing the properties of the model line are discussed.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 추계학술대회 논문집
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• pp.223-226
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• 2009

Various database and analysis system has been used for the cost effective maintenance of distribution facility but it is not effective because of the lack of interconnection among these systems. In order to overcome this problem this paper proposes reliability centered maintenance system based on the on-line monitoring of distribution system through intelligent distribution equipment. This system is made by the interconnection of distribution automation system, asset management system, failure analysis system and failure mode effect analysis system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1126-1131
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• 2008

In this paper we introduce an applicable RCM(Reliability centered maintenance) method for Track circuit equipment of AREX's Signalling System. AREX computerize all the process of FRACAS(Failure Reporting, Analysis and Corrective Action System)) by the Facility Management System of Integrated Information System. These datum were analysed and reproduced as the RAMS index value which can be used by maintenance staff for optimizing the maintenance method of the System.

• 산업경영시스템학회지
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• 제40권1호
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• pp.57-64
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• 2017

In order to reduce damages to major railroad components, which have the potential to cause interruptions to railroad services and safety accidents and to generate unnecessary maintenance costs, the development of rolling stock maintenance technology is switching from preventive maintenance based on the inspection period to predictive maintenance technology, led by advanced countries. Furthermore, to enhance trust in accordance with the speedup of system and reduce maintenances cost simultaneously, the demand for fault diagnosis and prognostic health management technology is increasing. The objective of this paper is to propose a highly reliable learning model using various machine learning algorithms that can be applied to critical rolling stock components. This paper presents a model for railway rolling stock component fault diagnosis and conducts a mechanical failure diagnosis of motor components by applying the machine learning technique in order to ensure efficient maintenance support along with a data preprocessing plan for component fault diagnosis. This paper first defines a failure diagnosis model for rolling stock components. Function-based algorithms ANFIS and SMO were used as machine learning techniques for generating the failure diagnosis model. Two tree-based algorithms, RadomForest and CART, were also employed. In order to evaluate the performance of the algorithms to be used for diagnosing failures in motors as a critical railroad component, an experiment was carried out on 2 data sets with different classes (includes 6 classes and 3 class levels). According to the results of the experiment, the random forest algorithm, a tree-based machine learning technique, showed the best performance.

• 한국신뢰성학회지:신뢰성응용연구
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• 제15권1호
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• pp.6-11
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• 2015

Maintenance plays an important role in keeping product availability, reliability and quality at an appropriate level. In this paper, two-types of maintenance policies are studied following the expiration of two-dimensional (2D) free replacement warranty. Both the fixed-maintenance-period policy and the variable-maintenance-period policy are based on a specified region of the warranty defined in terms of age and usage where all failures are minimally repaired. An accelerating failure time (AFT) model is used to allow for the effect of usage rate on product degradation. The maintenance model that arises following the expiration of 2D warranty is discussed. The expected cost rates per unit time from the user's point of view are formulated and the optimal maintenance policies are determined to minimize the expected cost rate to the user. Finally numerical examples are given to illustrate the optimal maintenance polices.

• 국제학술발표논문집
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.810-819
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• 2007

Usually the status of a bridge is determined by its structural capability and material strength. Consequently a lot of researchers have studied the failure, the fatigue, and the deterioration of the structure in terms of the structural function of a bridge. However, the overall performance of a bridge may be affected simply by the damage of one of its components. Therefore this study utilized a systematic classification and statistical analysis based on the existing bridge inspection data collected in Taiwan to reach the following goals: (1) assess the performance distribution and deterioration rate for bearing and expansion joint of bridge; (2) find out the right time to do the preventive and essential maintenance for the component of bridge with an empirical method, and to decide what time and which component of a bridge will receive preventive maintenance or regular maintenance.