• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.472-477
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• 2010

자동유량측정시설은 연속적인 유량자료를 측정하기 위해 운영되는 실시간-무인화 유량측정 시스템이다. 현재 국내 외에서 유량측정을 위해 설치 및 운영되고 있는 자동유량측정시설은 대부분 초음파유속계를 이용하고 있는는데, 초음파유속계는 유속을 측정하는 방식에 따라 크게 도플러방식 초음파유속계(ADVM, Acoustic Doppler Velocity Meter)와 이동시간차방식 초음파유속계(UVM, Ultrasonic Velocity Meter)로 분류된다. 본 연구에서는 각 방식별로 유량산정방법을 개선하기 위해 설치 운영 중인 자동유량측정시설 중 고령교 지점의 ADVM 방식과 여주, 적성 지점의 UVM 방식을 대상으로 측정성과에 대한 문제점을 분석하고 통계적인 방법을 통해 오측유속을 제거하거나 방식별 또는 지점별 특성을 고려하여 적절한 유량산정방법을 적용하였다. 그 결과 3개 지점에 대한 검증유량과의 평균 상대오차율은 모두 10% 이내로 나타났다.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.107-109
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• 2004

It is well known that on-site corona and various noises make severe problems on the PD(partial discharge) measurement. In this paper, for the improvement of the on-site PD measuring performance, the applicability of TF(Time-Frequency) map was investigated. For the purpose, PDs that can be generated from the defect in the power cables as well as corona discharges and ground noises were measured. And through the TF analysis for the measured data, we have tried to distinguish the real PDs, corona discharges and noises. As a result, it is confirmed that the data of PDs can be clustered themselves separable from other data such as corona and noises on the TF map.

• Electrical & Electronic Materials
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• v.11 no.11
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• pp.1-8
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• 1998

This paper presents an arificial neuro-fuzzy technique based prtial discharge (PD) pattern classifier to power system application. This may require a complicated analysis method employ -ing an experts system due to very complex progressing discharge form under exter-nal stress. After referring briefly to the developments of artificical neural network based PD measurements, the paper outlines how the introduction of new emerging technology has resulted in the design of a number of PD diagnostic systems for practical applicaton of residual lifetime prediction. The appropriate PD data base structure and selection of learning data size of PD pattern based on fractal dimentsional and 3-D PD-normalization, extraction of relevant characteristic fea-ture of PD recognition are discussed. Some practical aspects encountered with unknown stress in the neuro-fuzzy techniques based real time PD recognition are also addressed.

• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.5
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• pp.81-89
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• 1995

One of the most difficult problem to estimate the flood inflow is how to understand the effective rainfall. The effective rainfall is absolutely influenced by the condition of soil moisture in the watershed just before the storm event. DAWAST model developed to simulate the daily streamflow considering the meteologic and geographic characteristics in the Korean watersheds was applied to understand the soil moisture and estimate the effective rainfall rather accurately through the daily water balance in the watershed. From this soil moisture and effective rainfall, concentration time, dimensionless hydrograph, and addition of baseflow, the rainfall-runoff model for flood flow was developed by converting the concept of long-term runoff into short-term runoff. And, real-time flood forecasting model was also developed to forecast the flood-inflow hydrograph to the river and reservoir, and called RETFLO model. According to the model verification, RETFLO model can be practically applied to the medium and small river and reservoir to forecast the flood hydrograph with peak discharge, peak time, and volume. Consequently, flood forecasting and warning system in the river and the reservoir can be greatly improved by using personal computer.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.6
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• pp.641-648
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• 2008

A plate-type dielectric barrier discharge (DBD) reactor was designed and tested for removal of gaseous toluene. The DBD reactor consisted of 9 parallel plate electrodes, four of which were grounded. An AC voltage of rectangular waveform ($5{\sim}8.5kV$, $60{\sim}1,000Hz$), was applied to the other five electrodes. The gaseous toluene passed through the DBD reactor and its concentration was measured by a real-time gas analyzer. The carbon monoxide (CO) and carbon dioxide ($CO_2$) which were produced by decomposition of toluene in the DBD reactor, were sampled and analyzed by a micro gas chromatography. The maximum toluene removal efficiency was 51.4%.

• Journal of Electrical Engineering and Technology
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• v.11 no.3
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• pp.683-689
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• 2016

Most outdoor solid insulators may suffer from surface degradations due to non-stationary currents that flow on the insulator surface. These currents may be classified as leakage, discharge and tracking currents due to their disturbing potencies respectively. The magnitude of these currents depends on the degree of the contamination of surface. The leakage signals are followed by discharge signals and tracking signals which are capable of forming carbonized tracking paths on the surface between high voltage and earth contacts (surface tracking). Surface tracking is one of the most breakdown mechanisms observed on the solid insulators, especially polymers which may cause severely reduced lifetime. In this study the degradations observed on polyester resin based insulators are investigated according to the IEC 587 Inclined Plane Test Standard. The signals are monitored and recorded during tests until surface tracking initiated. In order to prevent total breakdown of an insulator, early detection of tracking signals is vital. Continuous Wavelet Transform (CWT) is proposed for classification of signals and their energy levels observed on the surface. The application of CWT for processing and classification of the surface signals which are prone to display high frequency oscillations can facilitate real time monitoring of the system for diagnosis.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1957-1959
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• 2000

The PD measurement method is very useful to detect insulation degradation. Recently, the HFPD(High Frequency Partial Discharge) measurement testing is widely used in partial discharge measurement of HV machines because HFPD measurement testing receives less influence of external noise and has a merit of good sensitivity. Therefore it is very useful method compare to previous conventional PD testing method and effective diagnosis method in power transformer that requires in-service diagnosis. But partial discharges have very complex characteristics of discharge pattern so it is required continuous research to development of precise analysis method. In this study, simulated transformer is manufactured and HFPD occurred from simulated transformer is measured with broad band antenna and active-line RF measurement system in real time, the degradation grade of transformer is analyzed through produced patterns in simulated transformer according to applied voltages. Also the PD pattern which was measured with EMC analyzer and RF measurement system is compared.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.1
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• pp.131-140
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• 1992

For a real-time flood forecasting and reservoir control problem of a multipurpose dam, the online acquisition of hydro-meteorological data and computerized analysis of the acquired data are absolutely necessary for the prompt decision of reservoir discharges which can minimize the possible damages and simultaneously maximize the utilization of the runoff. By introducing a man-machine interface such as condensed color graphics of the analyzed results, it is much easier and faster to transform the information to the decision maker who can decide the reservoir discharge. The newly developed PC-REFCON, which represents the PC based real-time flood forecasting and reservoir control, can easily handle the above problems by adopting a innovative decision support system. The system has three principal components of, a data base subsystem which acquires and manages real-time data, a model subsystem which forecasts the flood runoff and simulates the reservoir operation, and a dialogue subsystem which helps decision maker and system engineers using various graphics and tables with renovative methodologies. The developed PC-REFCON will be utilized from the coming Summer of 1992 for the flood control of all the nine multipurpose reservoirs in Korea.

• Korea Journal of Hospital Management
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• v.15 no.3
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• pp.143-169
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• 2010

This is a case study of Seoul St. Mary's Hospital applying a real-time enterprise (RTE) strategy to improve customer satisfaction and operational efficiency with the main process of medical institutions. The hospital is applying an RTE strategy to get real-time information on occurrences at each contact point of the main process of the medical institution from reservation to discharge through dashboard and to resolve issues through rapid decision-making. The RTE strategy of the hospital has some summaries: First, the hospital has linked a hospital management strategy to the RTE strategy to build a patient-centered treatment process. Second, the hospital has operated a control tower for change management and implementation monitoring in the process of implementing the RTE strategy. Third, the hospital has built systematic RTE-based environment as an application program in which the nU System is linked to Business Processor Renovation (BPR) promoted from 2006 on. Fourth, the hospital is applying a strategy to improve efficiency in operating the hospital by increasing customer satisfaction, removing inefficiency and variability, and managing medical resources efficiently through the RTE strategy. Fifth, it has established an information-sharing system through authority management for each user in terms of RTE information. Sixth, it has supplemented limitations of short-term information of the RTE strategy by linking the key performance index to the cost information system in order to improve performance of the RTE strategy. Seventh, it has improved customer satisfaction and achieved higher performance in improving operational efficiency, as compared with rival hospitals, through the RTE strategy.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.2
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• pp.188-193
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• 2007

Tracking and erosion of Poly Methyl Methacrylate (PMMA) and the suppression mechanism of alumina trihydrate were investigated in the present study The conventional testing as IEC-60587 is widely used in surface aging measurement of outdoor insulator those testing can carry out very short time for Lab testing. Also IEC-60587 testing is able to offer the standard judgement of relative degradation level of outdoor HV system. Therefore it is very useful method compare to previous conventional tracking testing method, But surface discharges(SD) have very complex characteristics of discharge pattern so it is required estimation research to development of precise analysis method. In recent, the study of IRR-Camera is carrying out discover of temperature of power equipment through condition diagnosis and system development of degradation diagnosis. In this paper, SD occurred from IEC-60587 is measured with the surface temperature of weibull distribution in real time, the degradation grade of SD is analyzed through produced patterns in IEC-60587 using Infrared Radiation(IRR) camera.