• 한국안전학회지
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• 제25권2호
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• pp.29-34
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• 2010

This paper is aimed to develop monitoring software for detecting the characteristics of current and voltage signals for series arc on electric wire. In order to attain this purpose, the characteristics of series arc were analyzed by the current and voltage signals on electric wire which were installed, and also analyzed by the changes of RMS, instantaneous of waveform value in time domain and THD in frequency domain. Monitoring program which analyze the signal was developed by Labview which can analyze in time domain and frequency domain, and save data. Experimental setup for detecting verification of monitoring program was composed loads of a lamp, an electric heater and an electric fan loads which were usually using. Measurement points for detecting verification of monitoring program were selected at both the panel board and the arc generator at the same time. As results of the experiments by monitoring program, the arc current waveform showed the same characteristic in all measurement points of all load. But the arc voltage waveform was different in each measurement point. When arc occurred, the THD of current value increased above 20%. The results of this study will be effectively used in developing the preventive system of electric fire by series arc.

• 한국광학회지
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• 제13권6호
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• pp.559-563
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• 2002

본 논문에서는 직접 고안한 scanned point-detecting system(SPDS)을 이용하여 PDP 방전 셀 내에서 방출되는 광을 3차원 적으로 시간 분해하여 측정하였다. PM tube를 통해 검출된 광 신호를 오실로스코프 상에서 파형을 확인하고 PC제어를 통해 결과를 얻었다. Ne-Xe(4%) 혼합가스가 400 ton압력으로 채워진 패널에서 측정한 시간 분해 결과를 살펴보면 패널의 전면판(top view)에서는 방전이 cathode전극의 안쪽 edge에서 시작되면서 cathode전극 바깥쪽으로 호의 형태를 이루면서 진행되는 것을 알 수 있었으며 패널의 측면(side view)에서 측정한 시간 분해 결과를 살펴보면 약 150$\mu\textrm{m}$의 높이까지 방전에 의한 광이 검출되었다. 그리고 구동전압 펄스가 인가된 후 730 ns에서 가장 큰 intensity가 나타났다.

• 한국농공학회논문집
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• 제52권1호
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• pp.1-11
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• 2010

Generation and transportation of runoff and pollutant loads within watershed generated eutrophication at Daecheong reservoir. To improve water quality at Daecheong reservoir, the best management practices should be developed and applied at upper watersheds for water quality improvement at downstream areas. In this study, two small watersheds of upper Daecheong reservoir were selected. The Long-Term Hydrologic Impact Assessment (L-THIA) model has been widely used for the estimation of the direct runoff worldwide. To apply the L-THIA ArcView GIS model was evaluated for direct runoff and water quality estimation at small watershed. And the Web-based Hydrograph Analysis Tool (WHAT) was used for direct runoff separating from total flow. As a result, the $R^2$ (Coefficient of determination) value and Nash-Sutcliffe coefficient value for direct runoff comparison at An-nae watershed were 0.81 and 0.71, respectively. And the $R^2$ value and Nash-Sutcliffe coefficient value at Wol-oe were 0.95 and 0.93. The $R^2$ value of BOD, TOC, T-N and T-P at An-nae watershed were BOD 0.94, TOC 0.81, T-N 0.94 and T-P 0.89. And the $R^2$ value of BOD, TOC, T-N and T-P at Wol-oe watershed were BOD 0.80, TOC 0.93, T-N 0.86 and T-P 0.65. The result that estimated pollutant loadings using the L-THIA ArcView GIS model reflected well the measured pollutant loadings except for T-P in Wol-oe watershed. With L-THIA ArcView GIS model, the direct runoff and non-point pollutant (NPS) loadings in the watershed could be analyzed through simple input data such as daily rainfall, land uses, and hydrologic soil group.

• 한국조경학회지
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• 제29권1호
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• pp.22-31
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• 2001

The purpose of this study is to compare calculated pollutant loadings using pollutant load unit factors and vector type coverage, and expected mean concentration(EMC) and raster type of digital elevation model(DEM). This study is also focusing on comparison of the advantages and the disadvantages of the two methods, and seeking for a method of calculation of pollutant loadings using DEM. Estimation of pollutant inputs using pollutant load unit factors has limitations in identifying seasonal variations of pollutant loadings. Seasonal changes of runoffs should be considered in the calculation of pollutant loadings from catchments into reservoirs. Evaluation of pollutant inputs using runoff-coefficient and EMC can overcome these drawbacks. Proper EMC and runoff-coefficient values for the Koeup stream catchments of the Koheung estuarine lake were drawn from review of related papers. Arc/Info was employed to establish database of spatial and attribute data of point and non-point pollutant sources and characteristics of the catchments. ArcView was used to calculate point and non-point pollutant loadings. Pollutant loads estimated with either unit factors-coverages, i.e., pollutant load unit factors and vector coverages f point sources and land use, or EMC and digital elevation mode(DEM) were compared with stream monitoring loads. We have found that some differences were shown between monitoring results and estimated loads by Unit Factors-Coverage and EMC-DEM. Monthly variations of pollutant loads evaluated with EMC-DEM were similar to those with monitoring result. The method using EMC-DEM can calculate accumulated flows and pollutant loads and can be utilized to identify stream networks. A future research on correcting the difference between vector type stream using flow direction grid and digitalizing vector type should be conducted in order to obtain more exact calculation of pollutant loadings.

• 한국조경학회지
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• 제28권6호
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• pp.114-126
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• 2001

The purpose of this study is to establish the databases of pollutant sources and water quality measurement data by utilizing GIS, and making the user interface for the management of pollutant sources. Yeongsan Estuarine Lake was formed of a huge levee of 4.35 km constructed by an agricultural reclamation project. Water quality of the reservoir has been degraded gradually, which mainly attributes to increase of point and non-point source pollutant loads from the lake's watershed of 33,374.3 $\textrm{km}^2$ into it. Application of GIS to establishment of the database was researched of pint source such as domestic sewage, industrial wastewater, farm wastes, and fishery wastes, and non-pont source such as residence, rice and upland field, and forest runoffs of the watershed of the lake. NT Acr/Info and ArcView were mainly utilized for the database formation. Land use of the watershed using LANDSAT image data was analyzed for non-point source pollutant load estimation. Pollutant loads from the watershed into the reservoir were calculated using the GIS database and BOD, TN, TP load units of point and non-point sources. Total BOD, TN, TP loads into it reached approximately to 141, 715, 2,094 and 4,743 kg/day respectively. The loads can be used as input parameters for water quality predicting model of it. A user-friendly interface program was developed using Dialog Designer and Avenue Script of AcrView, which can perform spatial analysis of point and non-point sources, calculate pollutant inputs from the sources, update attribute data of them, delete and add point sources, identify locations and volumes of water treatment facilities, and examine water quality data of water sampling points.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.731-736
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• 2001

Nowadays various simulation tools are widely used for the design and the analysis of power electronic converters. From the engineering point of view it is rather difficult to parameterize power semiconductor device models without the knowledge of basic physical parameters. In recent years some data sheet driven behavioral models or so called 'wizard' tools have been introduced to solve this problem. In this contribution some experiences with some user-friendly power semiconductor models will be discussed. Using special simulation test circuits it is possible to get information on the static and dynamic behavior of the parameterized models before they are applied in more complex schemes. These results can be compared with data sheets or with measurements. The application of these models for power loss analysis of inverter type arc welding power sources will be described.

• Nuclear Engineering and Technology
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• 제51권1호
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• pp.317-324
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• 2019

A high energy arcing fault event occurred in the medium-voltage (13.8 kV and 4.16 kV) metalclad switchgears in a nuclear power plant not only affecting switchgear but also connected equipment due to the arc energy. The high energy arcing fault also causes a fire that influences the safety function of the unit. Therefore, from the safety point of view, it is necessary to evaluate the influences of high energy arcing fault events on the safety functions of nuclear power plants. The purpose of this paper is to elaborate the characteristics of high energy arcing faults and propose a high energy arcing fault mitigation scheme for medium voltage networks in nuclear power plants.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 전력전자학술대회 논문집
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• pp.260-264
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• 1998

Three phase Boost/Buck converter which have economical merits and simple control scheme, are analyzed and evaluated through comparative methods and digital simulation for equivalent load. Those play a part of voltage boost/buck as well as power factor correction with single switch. Controller operating in constant and variable frequency is used for rapid output response and stable system condition respectively. Moreover low THD property of single switched converters is available for inverter arc welding machine known as high power and low power factor. So, in this paper a comparison of the characteristics in boost and buck converter is described and then simulation results conforms the merits from point of view of power factor and voltage regulator.

• 대한공간정보학회지
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• 제4권1호
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• pp.57-66
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• 1996

본 연구에서는 현재 제작되고 있는 자동차 항법용 수치지도의 GIS 툴로의 변환과 공유가 가능함을 확인하고, GIS에서 사용되는 수치지도 데이타베이스 구조의 연구를 통해 사용자의 관점에서 수치지도의 적용 방안을 제시하고자 한다. 이를 위하여 먼저 기구축된 수치지도의 데이타 구조를 분석하여 GIS 툴-ARC/INFO-로의 효과적인 변환을 하기 위해 데이타 모델을 설계하였고, 기존 수치지도 데이타의 변환을 위한 프로그램을 작성함으로써 기구축된 수치지도와 GIS 툴의 데이타베이스와 연결할 수 있는 변환 툴을 제시하였다.

• 전기학회논문지
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• 제59권5호
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• pp.897-903
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• 2010

This paper presents a response surface method(RSM) with Latin Hypercube Sampling strategy, which is employed to optimize a magnet pole shape of large scale BLDC motor to minimize the cogging torque. The proposed LHS algorithm consists of the multi-objective Pareto optimization and (1+1) evolution strategy. The algorithm is compared with the uniform sampling point method in view points of computing time and convergence. In order to verify the developed algorithm, a 6 MW BLDC motor is simulated with 4 design parameters (arc length and 3 variables for magnet) and 4 constraints for minimizing of the cogging torque. The optimization procedure has two stages; the fist is to optimize the arc length of the PM and the second is to optimize the magnet pole shape by using the proposed hybrid algorithm. At the 3rd iteration, an optimal point is obtained, and the cogging torque of the optimized shape is converged to about 14% of the initial one. It means that 3 iterations aregood enough to obtain the optimal design parameters in the program.