• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.677-682
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• 2000

본 연구는 전동기의 부분방전에 의해 발생되는 전자파를 측정하여 전동기의 열화상태를 진단할 수 있는 진동기 절연열화 진단시스템을 설계하였다. 청장 전동기에서 부분방전에 의한 전자파를 on-line으로 측정하고, 측정된 데이터로부터 정량화된 특징 데이터를 추출한 후 전자파의 평균 에너지 분포를 이용하여 전동기의 절연열화 상태를 판단하는 방법을 제시하였으며, 현장에서 사용 중인 Megger시험과 비교하였다.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.480-483
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• 1998

For memory products, it is very important to develop a new production line as soon as possible. All products are inspected to get rid of defected products at the last testing stage. Those inspection data are called FCM. In this paper, based on the FCM data, Area Usage Factor (AUF) analyzing method will be proposed. Process engineers can make up their mind to which direction they should concentrate their analyzing power.

• Solar Energy
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• v.16 no.2
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• pp.7-14
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• 1996

Korean goverment is promoting "the Rural Electrification Project" to replace the diesel generators with PV power supply. The PV-diesel hybrid system are proven more cost effective than that of the existing, especially in the. case of small islands(less than 70 households). In this paper, we intend to introduce the Hahwado island PV system assisted with diesel generator and remote monitoring systems as observator. The purpose of this observator is to have minimum maintenance, to improve economical effciency and system reliability by checking the system periodically at certain time interval, and to make diagnosis of its operating situations. The remote monitoring system was designed to communicate between the central and local site through exclusive telephone line on real-time base, using Window '95 version.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.264-270
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• 1998

This research broadens the prime concern of nuclear power plant operations from safe performance to both economic and safe performance. First emergency diesel generator is identified as one of main contributors for the lost plant availability through the review of plants forced outage records. The framework of an integrated architecture for performing modern on-line condition for operational availability improvement is configured in this work. For the development of the comprehensive sensor networks for complex target systems, an integrated methodology incorporating a structural hierarchy, a functional hierarchy, and a fault-system matrix is formulated. The second part of our research is development of intelligent diagnosis and maintenance advisory system, which employs Bayesian Belief networks (BBNs) as a high level reasoning tool incorporating inherent uncertainty use in probabilistic inference. Our prototype diagnosis algorithms are represented explicitly through topological symbols and links between them in a causal direction. As new evidence from sensor network development is entered into the model especially, our advisory of system provides operational advice concerning both availability and safety, so that the operator is able to determine the likely modes, diagnose the system state, locate root causes, and take the most advantageous action. Thereby, this advice improves operational availability

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.11
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• pp.661-667
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• 2003

It has little possibility that a cable causes any problem in electric power facilities. But when a trouble occurs in cable or cable joint, the damage is very severe. The main causes of the cable defections are bad cable making procedure, poor cable operation and deterioration according to the years. There are some cases to have potential problems due to many cable connection points, because of short length of cable, especially in 154㎸ system. In this study, novel method to measure partial discharge in cable joints is proposed and the effectiveness and the reliability of the proposed method is shown through experiment results of field.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.627-629
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• 1999

This paper presents a new FDI scheme based on dynamic fuzzy model(DFM) for the nonlinear system. The dynamic behavior of a nonlinear system is represented by a set of local linear models. The parameters of the DFM are identified in on-line and aggregated to generate a residual vector by the approximate reasoning. The neural network classifer learns the relationship between the residual vector and fault type and used both for the detection and isolation of process faults We apply the proposed FDI scheme to the FDI system design for a two-tank system and show the usefulness of the proposed scheme.

• Journal of Mechanical Science and Technology
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• v.20 no.7
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• pp.929-940
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• 2006

Early detection and diagnosis of incipient induction machine faults increases machinery availability, reduces consequential damage, and improves operational efficiency. However, fault detection using analytical methods is not always possible because it requires perfect knowledge of a process model. This paper proposes a neural network based expert system for diagnosing problems with induction motors using vibration analysis. The short-time Fourier transform (STFT) is used to process the quasi-steady vibration signals, and the neural network is trained and tested using the vibration spectra. The efficiency of the developed neural network expert system is evaluated. The results show that a neural network expert system can be developed based on vibration measurements acquired on-line from the machine.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.206-207
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• 2007

We developed a measurement system for on-line test and evaluation of performances of KHST. The measurement system is composed of software part and hardware part. Perfect interface between multi-users is possible. A new method to measure temperature was applied to the measurement system. By using the system, fault diagnosis and performance evaluation of electric equipment in Korean High Speed Train was conducted during test running.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.3073-3078
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• 2011

Driverless Train Control System has been recently introduced and commercialized in Korea. It is expected that the vehicle with driverless operation system will be used in new lines such as Sinbundang line soon. Therefore it is necessary to change the system operation and conception of the existing train operation system and the necessity of driverless vehicle monitoring system meeting a new paradigm is rising. In order to dispel concerning about safety issues caused by driverless train operation, the importance to establish vehicle error detection, useful fault diagnosis and rapid action plans is higher than ever. For this, efficient and higher level of vehicle supervision & control system should be essentially supported. In this study, remote driverless vehicle monitoring system using by radio communication is suggested to be used for monitoring and controlling important parts of the vehicle and diagnose and take quick actions when vehicles are in trouble at control tower at real time.

• Journal of the Korean Institute of Gas
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• v.8 no.2 s.23
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• pp.28-34
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• 2004

Enhanced methodologies for process diagnosis and abnormal situation management have been developed for the last two decades. However, there is no single method that always shows better performance over all kinds of diagnostic problems. In this paper, a framework of message-passing, cooperative, intelligent diagnostic agents is presented for improved on-line fault diagnosis through cooperative problem solving of different expertise. A group of diagnostic agents in charge of different process functional perform local diagnoses in parallel; exchange related information with other diagnostic agents; and cooperatively solve the global diagnostic problem of the whole process plant or business units just like human experts would do. For their better understanding, sharing and exchanging of process knowledge and information, we also suggest a way of remodeling processes and protocols, taking into account semantic abstracts of process information and data. The benefits of the suggested multi-agents-based approach are demonstrated by the implementations for solving the diagnostic problems of various chemical processes.