• Journal of Power Electronics
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• 제16권6호
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• pp.2202-2211
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• 2016

In certain applications, such as IPT-based EV charger (IPTEC), any variation in alignment and distance between pickup and charger primary leads to a change in leakage and magnetic impedance magnitudes. The power transmission capacity is not always at the maximum level because of these variations. This study proposes a new low-cost tracking method that achieves the Maximum Inductive Power Transmission Capacity (MIPTC). Furthermore, in the proposed method, the exchange of information between load and source is not required. For an application such as IPTEC, the load detected by the IPTEC varies continuously with time because of the change in state of the charge. This load variation causes a significant variation in IPT resonant circuit voltage gain. However, the optimized charging output voltage should be kept constant. From the analysis of the behavior of the IPT circuit at different working frequencies and load conditions, a MIPTC operation point that is independent of load condition can be identified. Finally, the experimental results of a developed prototype IPT circuit test show the performance of the proposed method.

• 전기학회논문지
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• 제63권1호
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• pp.35-41
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• 2014

This paper presents a design method of programmable low pass filter(PLPF) which reduce an estimation error of a zero crossing point(ZCP) for a high speed brushless DC(BLDC) motor drive. BLDC motor sensorless drive is possible by estimation of ZCP. The ZCP estimated by detecting a change of back-EMF polarity has the estimation error because noises exist on the measured back-EMF. Therefore a calculated commutation timing using the ZCP is inaccurate. And the inexact commutation timing leads to ripples of 3-phase current and degradation of drive performance. This paper proposes the design method of the PLPF to overcome these problems. First, a speed calculated a inaccurate period of the ZCP is analyzed in the frequency domain. Then, the PLPF that has varying cut-off frequency according to change of the speed is designed on the frequency analysis result. The proposed method is verified by the experiment.

• 한국전산유체공학회지
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• 제5권2호
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• pp.38-46
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• 2000

It has been indicated that the rotor/stator interaction has distinct causes of unsteadiness, such as the viscous vortex shedding, wake/stator interaction and potential rotor/stator interaction. In this paper, the mechanism of unsteady potential interaction in one stage axial compressor is numerically investigated for blade row ratio 1:1 and 2:3 at design point and for blade row ratio 2:3 at off-design point in two-dimensional view point. The numerical technique used is the upwind scheme of Van-Leer's Flux Vector Splitting(FVS) and Cubic spline interpolation is applied on zonal interface. In this study the flow unsteadiness due to potential interaction are found to be larger in blade row ratio 2:3 than in 1:1. The total pressure rise in blade row ratio 2:3 is closer to the real value in design point than that in 1:1. The change of unsteady pressure amplitude according to the variation of stator exit pressure is very small.

• 제어로봇시스템학회논문지
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• 제15권5호
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• pp.525-529
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• 2009

Most of FLC received input data from error e and change-of-error e' with no relation with system complexity. Basic scheme follows typical PD and PI or PID Controller and that has been developed through fixed ME In this paper, We studied the relationship between MF and system response and system response through changing Fuzzy variable of consequence MF and propose the simple FLC using this relationship. The response of FLC is changed according to the width of Fuzzy variable of consequence MF. As changing the Fuzzy variable of consequence MF shows various nonlinear characteristic, we studied the relation between response and MF using analytical method. We designed the effective FLC using three-variable MF and nine rules and took simulation for verification. In this study, we propose the method to design system with FLC in stability point which is an impotent characteristic of designing system. The circle criterion which is adapted to analysis the nonlinear system is put to use for proposed method. Since SISO FLC has a time-invariant and odd characteristic we can use the critical point not disk which is generally used to determine the stability in the circle criterion, to determine the stability. Using this, we can get the maximum critical point plot of SISO FLC with changing the consequence fuzzy variables. The predetermined critical point plot of FLC can be used to decide the region of the system to be stable. This method is effectively used to design the SISO FLC.

• 지적과 국토정보
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• 제46권2호
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• pp.197-209
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• 2016

The Marcellus Shale industry has impacted Pennsylvania since 2005 and has been a major driver of land use change ever since. The Pennsylvania state park system has been facing encroachment from this industry ever since the first Pennsylvania wellpad was drilled in 2008. Previous research conducted overviews the impacts associated with this industry in regards to environmental quality, but there is limited research associated with the social impacts. The conducted research overviews the Marcellus Shale industry in regards to encroachment on Pennsylvania state parks through a GIS analysis. The purpose of the research is to evaluate how the viewsheds (areas of vision from a given point) of Pennsylvania state park land has been impaired by the Marcellus Shale industry. The results of the research show how the landscape of state parks have change due to the Marcellus Shale industry, and also a focus will be placed on scenic vistas (areas that highlight spectacular views within state parks) of selected parks to see to what extent that pristine landscape has been altered. The results of the research will help provide an idea of landscape change utilizing a GIS analysis and hopefully help to guide future growth.

• 한국초등과학교육학회지:초등과학교육
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• 제34권3호
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• pp.288-296
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• 2015

This study aimed to analysis of concepts and inquiry activities related to the 'Earth Science' area in the South Korean elementary school textbooks to the current and to seek the improvement of future textbook. For the study, we were collected South Korean elementary school textbooks to the current. After the collection had been made, we were analyzed related to the 'Earth' area in the South Korean elementary school textbooks and were extracted central concepts and inquiry activities. The result of this study: First, there were 'A change in the land', 'Strata and Fossil', 'Volcanoes and Earthquakes', 'Earth and Moon', 'The weather', 'The Solar system and the Star', and 'Seasonal Change' in the central concepts related to the 'Earth' area in the South Korean elementary school textbooks to the current. Second, central concepts were almost the same but the curriculum was changed. Third, inquiry activities also were confirmed to be maintained with little change. This result was believed that it can provide a variety of suggestions at this point in changing the curriculum.

• 한국통신학회논문지
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• 제35권11B호
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• pp.1651-1658
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• 2010

최근 들어 삶의 지표가 향상됨에 따라 질병이 발생되지 전에 조기 진단하는 예방, 보건의 건강 패턴이 행해지고 있다. 이와 같은 예방, 보건 분야를 반영하는 대체의학으로 수지침 요법이 널리 사용되고 있다. 따라서 본 논문처리 기술을 이용하여 성장에 해당하는 상응점인 A16 혈자리를 자극하여 심장과 관련된 음성 요소의 변화를 측정하고 상호간의 비교, 분석을 통해 성장 가능의 향상을 측정하였다. 이를 위해 우선 심장 상응점인 A16 혈자리를 자극하기 전과 후의 음성을 수집하였으며 심장과 연관성이 있는 음성 신호 분석 요소인 제2포먼트 대역폭과 지터를 적용한 실험을 수행하였다. 결과적으로, A16 혈자리 자극에 의해 제2포먼트 대역폭과 지터가 낮아지는 결과를 추출했으며 이를 통해 IT 음성 신호 처리 기술을 이용하여 심장 기능이 향상되는 것을 입증할 수 있었다.

• 대한인간공학회지
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• 제18권2호
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• pp.25-34
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• 1999

The objective of this study is to evaluate the emotional change of a driver according to the change of temperature, humidity, $CO_2$ gas concentration and $C_4H_{10}$ gas concentration in the automobile by electroencephalogram(EEG) spectrum analysis. The experiment was performed in an automobile simulated shielding room with healthy volunteers(age : 18-31, male : 14, female : 7). The subject's emotion at every different condition was indexed 11-point scale(+5 : most pleasant, -5 : least pleasant). The emotion index at each condition resulted in as follows; in temperature $1.00(23.5^{\circ}C)$, $-2.33(30.5^{\circ}C)$, in humidity 1.50(45%), -1.50(65%), in $CO_2$ gas concentration 0.67(500ppm), -0.57(6,000ppm), in $C_4H_{10}$ gas concentration -0.25(0ppm), -2.75(1,200ppm). From EEG spectrum analysis, the average mean power frequency(MPF) value at each different condition was shown as follows; in temperature $5.48(23.5^{\circ}C)$, $4.06(30.5^{\circ}C)$, in humidity 11.03(45%), 3.03(65%), in $CO_2$ gas concentration 7.16(500ppm), 6.38(6,000ppm), in $C_4H_{10}$ gas concentration 10.21(0ppm), 2.87(1,200ppm). When the environment became unpleasant to the subject, all of the obtained MPF values were decreased. It was found that there is close agreement between subjective evaluation by subject's scaling and objective evaluation by EEG spectrum analysis at different environment. These results indicated that the EEG spectrum analysis is a proper method to assess emotional response of a driver in the changing automobile environment.

• Spatial Information Research
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• 제20권3호
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• pp.39-50
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• 2012

본 연구는 금강유역을 대상으로 과거 약 30년간의 기상 수문시계열자료들을 수집해 다양한 통계분석을 수행하여 기후변화의 영향을 정량적으로 파악하고자 하였다. 기상자료로 금강유역 기상관측소 8개소의 37개년(1973~2009)의 기온, 강수량, 상대습도 자료를 수집하였고, 하천수위자료는 수위자료와 수위-유량관계곡선의 신뢰성 문제, 이후 수행될 장기유출분석을 고려하여 공주, 규암 수위관측소의 36개년(1973~2008)의 자료를 이용하였다. 수집된 자료의 평균, 표준편차, 왜곡도, 변동계수를 산출하여 연 계절별로 수문기상인자의 경년변화를 파악한 결과 기상인자 중 강수량의 변동성이 가장 크게 나타나 경년별 변화가 큰 것으로 분석되었다. 수문학적 지속성 분석을 위해 Run 검정, Turning Point 검정, Anderson Exact검정을 이용하여 시계열자료에 주기성이 있는지 분석한 결과 기온과 강수는 무작위성, 상대습도, 하천수위는 지속성을 가지는 인자로 분석되었고 지하수위는 관측소별, 기간별로 무작위성과 지 속성이 혼재되어 있는 것으로 나타났다. 또한, 경향성 분석을 위해 단순 선형 회귀분석과 Mann-Kendall 검정법을 이용한 결과 기온은 연 계절 모두 증가경향이 나타났고, 강수량은 여름에만 증가경향이 나타났으며, 상대습도는 뚜렷한 감소경향을 보였다. 본 연구의 결과는 기후변화로 인해 발생될 수 있는 수자원의 영향을 평가하고 미래 물 관리 적응기술 개발 및 계획 수립을 위한 자료로 활용될 수 있을 것으로 사료된다.

• 한국조경학회지
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• 제43권5호
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• pp.13-27
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• 2015

본 연구는 도시 내 녹지 공간을 대상으로 기후변화로 인한 재해 위험도를 평가하였다. 재해유형, 녹지공간 유형에 따른 평가를 실시하였으며, 수해와 풍해, 평지형 공원과 산지형 공원으로 유형화 시키고, 각 유형별 평가항목으로는 자연적 요소 인공적 요소 사회적 요소로 구분하여 평가 분석하였다. 연구의 주요결과는 다음과 같다. 수해로 인한 재해 위험도 표준화 점수는 평지형 공원의 경우, 아시아 공원이 55.800점으로 서울숲 51.775점보다 높았으며, 산지형 공원의 경우 도곡 공원 58.428점, 배봉산 공원 58.374점의 지수를 보이고 있었다. 풍해로 인한 재해 위험도 표준화 점수를 살펴보면 우선 평지형 공원의 경우, 아시아 공원이 64.763점으로 서울숲 61.054점보다 높았으며, 산지형 공원의 경우, 배봉산 공원이 58.533점으로 도곡 공원 55.459점보다 높은 지수를 나타냈다. 기후변화 재해로 인한 오픈스페이스 위험도 평가의 필요성과 가치를 제기하고, 오픈스페이스만의 재해 위험도 평가모형을 정립하여 위험도 평가를 시도하였으며, 도시 녹지공간의 재해 위험도를 제고하였다.