• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권9호
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• pp.403-407
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• 2005

Most of the loads in industrial power distribution systems are balanced and connected to three power systems. However, voltage unbalance is generated at the user's 3-phase 4-wire distribution systems with single & three phase. Voltage unbalance is mainly affected by load system rather than power system. Unbalanced voltage will draws a highly unbalanced current and results in the temperature rise and the low output characteristics at the machine. It is necessary to analyse correct voltage unbalance factor for reduction of side effects in the industrial sites. Voltage unbalance is usually defined by the maximum percent deviation of voltages from their average value, by the method of symmetric components or by the expression in a more user-friendly form which requires only the three line voltage readings. If the neutral point is moved by the unbalanced load at the 3-phase 4-wire system. Line and phase voltage unbalance leads to different results due to zero-sequence component. So that it is difficult to analyse voltage unbalance factor by the conventional analytical method, This paper presents a new analytical method for phase and line voltage unbalance factor in 4-wire systems. Two methods indicate exact results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.301-304
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• 2001

Wind power generation system is one of the most useful energy resource using natural environment. One of the biggest problem we encountered is toot the wind speed is fluctuating sharply according to the weather conditions rather than it is stable. In this paper we do the equivalent modeling the mechanical energy of wind power turbine according to wind speed into the synchronous generator. We analyse the equivalent modeling output part of rectifier into DC/DC converter input part theoretically. We analyse a battery charging characteristics for power storage enabling the supply of stable power to the load. We design a system and do the modeling of it analytically so that it supplies a stable power to the load by constructing a DC-AC inverter point. Also we make a small size model usable in actual wind power generation system of 30kw and make an experiment and confirm its validity.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.153-156
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• 2001

Maximum Power Point Tracking(MPPT) Is used in wind power generation systems to maximize wind power turbin output power, irrespective of wind speed conditions and of the load electrical characteristics. In this paper we do the equivalent modeling the mechanical energy of wind power turbine according to wind speed into the synchronous generator. We analyse the equivalent modeling output part of rectifier into DC/DC converter input part theoretically. We design a control algorithm for variable voltage according to wind speed intensity and density so that load voltage of chopper is controlled steadily using the maximum power point tracking(MPPT) control method. We analyse a battery charging characteristics and a charging circuit for power storage enabling the supply of stable power to the load. We design a system and do the modeling of it analytically so that it supplies a stable power to the load by constructing a DC-AC inverter point. Also we design a charging circuit usable in actual wind power generation system of 30kW and confirm its validity.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.814-819
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• 2004

When we evaluate sound, there are various methods for noise such as A-weighted SPL(sound pressure level), NC(noise criteria), NR(noise rating) and SIL(speech interference level) etc. however, it is not sufficient for the sounds supplied to public places used in soundscape design. Consequently it is needed to develop the tool for evaluating the good acoustical environment and futhermore quantifying the effect of improvement by supplying sound sources. In this study, it was tried to analyse the sound sources applied for soundscape design using sound quality parameters. The sound sources used were natural sound artificial sound. For the sound quality parameters, Loudness(L), Sharpness(S), Fluctuation strength(FL), Tonality(T), Roughness(R), Unbiased Annoyance(UA) were used and sound quality values were compared both natural and artificial sounds, depending on the convolution of sound sources with background noise, the duration, the frequency contents and the SPL. As a result, the values of L and UA have shown to be changed comparing to the other parameters, and it is necessary to analyse the correlation with subjects' responses.

• 한국측량학회지
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• 제7권2호
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• pp.1-6
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• 1989

수준망의 조정계산은 관측방정식에 의한 최소제곱법을 사용하여 등급별로 독립적인 순차조정을 실시하는 것이 일반적이다. 그러나 망의 규모가 작을 경우에는 자유도가 낮기 때문에 통계분석에 어려움이 있고 저등급의 망에 대한 오차를 정확히 평가하기가 곤란하다. 본 연구에서는 1967년∼1987년간에 측정된 우리나라의 측지수준망자료를 이용하여 1,2등수준망을 혼합시켜서 조합조정하는 방법을 논하였으며 조합조정의 특성을 분석하였고 타원보정에 따른 영향과 조정원점의 변화에 따른 영향을 분석하였다. 또한 실수자유도에 의한 망의 강도분석과 분산요소값의 추정에 의한 망의 정확도를 산출하여 우리나라 측지수준망을 평가하였다.

• 한국철도학회논문집
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• 제10권5호
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• pp.463-472
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• 2007

본 논문에서는 궤도 각 부의 가속도 특성과 가속도에 영향을 미치는 인자들과의 상관관계를 분석하였다. 이를 위해서 경부고속철도 자갈궤도에 대해서 레일, 침묵, 자갈도상의 진동가속도를 측정하였다. 측정된 가속도에 대해서 실효치(RMS)를 분석하였으며 궤도의 진동에 영향을 미치는 매개요소로 패드강성, 고저틀림, 주행속도 및 요철을 고려하였다. 진동가속도와 매개요소들과의 상관관계 분석을 위해서 선형회귀식을 적용하였으며, 이를 통해서 상관계수를 도출하였다. 또한 가속도의 주파수 특성을 분석하기 위하여 1/3 옥타브 해석을 실시하였다.

• 한방안이비인후피부과학회지
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• 제27권4호
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• pp.87-100
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• 2014

Objectives : This study is aimed to analyse immunohistochemical research trend on psoriasis and consider the results in terms of Korean medicine. Methods : We analyse both immunohistochemical research papers and Korean medical papers on psoriasis, which I searched using KISS(Korean studies Information Service System) and OASIS(Oriental Medicine Advanced Searching Integrated System). Results : Psoriasis is characterized by hyperporliferation of the epidermis, inflammatory cell accumulation and increased tortuosity and dilatation of dermal papillary blood vessels. Recently, angiogenesis is considered to play a major role in pathogenesis of psoriasis. Conclusion : In Korean medicine, blood-tonifying, blood-cooling and blood-activating medicinal herbs have generally been used to treat psoriasis. I consider these herbs which also treat vessel problem can have an effect on angiogenesis of psoriasis.

• 한국기후변화학회지
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• 제9권1호
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• pp.69-74
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• 2018

The purpose of this study is to suggest the methodology of $CO_2$ Emission Factor Verification and Quantitative Assessment in Ethylene Product Processes. At first, this study compare the IPCC (Intergovernmental Panel on Climate Change) 1996 Guideline and 2006 Guideline. And analyse methodology for estimating $CO_2$ emission and $CO_2$ emission factor in Ethylene product process. Also analyse cases of estimating $CO_2$ emission factor based on material balance. Methodology of $CO_2$ Emission Factor Verification and Quantitative Assessment are following the categories proposed by GIR (Greenhouse Gas Inventory and Research Center). There are total 12 factors in 8 categories and give 5 or 10 points according to their importance. Also this study suggests necessary data of document to meet the conditions. The result would help estimate accuracy Greenhouse Gas Inventory. Also contribute to establish policy on environmental assessment, air conservation, etc.

• Journal of applied mathematics & informatics
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• 제39권1_2호
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• pp.197-214
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• 2021

In this paper, we have studied dynamics of fractional order mathematical model of malaria transmission for two groups of human population say semi-immune and non-immune along with growing stages of mosquito vector. The present fractional order mathematical model is the extension of integer order mathematical model proposed by Ousmane Koutou et al. For this study, Atangana-Baleanu fractional order derivative in Caputo sense has been implemented. In the view of memory effect of fractional derivative, this model has been found more realistic than integer order model of malaria and helps to understand dynamical behaviour of malaria epidemic in depth. We have analysed the proposed model for two precisely defined set of parameters and initial value conditions. The uniqueness and existence of present model has been proved by Lipschitz conditions and fixed point theorem. Generalised Euler method is used to analyse numerical results. It is observed that this model is more dynamic as we have considered all classes of human population and mosquito vector to analyse the dynamics of malaria.

• 정보보호학회논문지
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• 제19권6호
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• pp.161-174
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• 2009

IPTV에서는 제한수신시스템(Conditional Access System, CAS)을 사용하여 자격을 갖춘 시청자 만이 시청이 가능하도록 한다. 현재까지 CAS는 set-top box 혹은 cable card를 이용하여 사용자에게 서비스를 제공하는 것이 일반적이었지만 근래에는 기기간 호환성 문제 해결, DRM 등 다른 서비스와의 연동 문제 해결, 안전성 확보 등을 이유로 다운로드 가능한 CAS 시스템(Downloadable CAS, DCAS)에 대한 연구가 이루어 지고 있다. 본 논문에서는 오픈 케이블 기반의 DCAS 시스템의 취약성을 분석 및 보완하여 안전한 DCAS 시스템을 제안한다. 또한 제안한 시스템의 구현결과를 보여 요구사항에 대한 만족도를 분석한다.