• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 춘계학술대회 논문집
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• pp.322-327
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• 1999

In most railway vehicle applications, a single phase AC/DC converter is used greatly and is essential equipment for Korea High Speed Train. A diode bridge rectifier and a phase-controlled thyristor bridge rectifier generate harmonics in power system. Nowadays, power factor and harmonics become major issue in electrical equipment for railway vehicle. Many researchers have been trying to improve the power factor and ac-side harmonics. Therefore the PWM converter is used to operate at unity Power factor and to reduce ac-side current harmonics. This paper describes the circuit for AC/DC PWM converter of Korea High Speed Train and proposes control algorithm to realize the sinusolidal input current waveform and the effective unity power factor. The validity of the proposed control method is verified through the experimental result.

• 한국전문물리치료학회지
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• 제3권3호
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• pp.82-91
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• 1996

Normal balance is defined as state in which the body is equlilibrium. It is complex motor control task, requring integration of sensory information, neural processing, and biomechanical factors. There are major two factors contribute to balance control, the neurological and the musculoskeletal. The neurological factor provides the sensory processing and motor output mechanisms that are the neurophysiological basis for response. The musculoskeletal factor provides the mechanical structure for response. When all components of two factors are operating effectively, the postural response should be appropriate and effective for good balance control. Therfore, balance can be influenced by above all factors. In addition, balance can be also influenced by muscle tone, hearing, physiological factors, and environmental factors. Physical therapists must understand factors of balance control so that we can accurately assess balance. Therefore, physical therapists have to develop useful balance measurement tools to evaluate balance.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 추계학술대회 논문집
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• pp.219-225
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• 1998

A Diode bridge rectifier and a phase-controlled thyristor bridge rectifier generate harmonics in power system. Nowadays, power factor and harmonics are important performance in electrical equipment for railway vehicle. Many researchers have been trying to improve the power factor and ac-side harmonics. Therefore the PWM converter has been used to operate at unity power factor and to reduce ac-side current harmonics. This paper proposes the synchronization loop by vector product in single-phase PWM converter. The proposed control method can realize the sinusolidal input current waveform and the effective unity power factor. The validity of the proposed control method is verified through the experimental result.

• 디지털융복합연구
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• 제13권11호
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• pp.529-537
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• 2015

본 연구는 융복합 시대 어린이 전용 수영장의 서비스품질과 만족의 관계에서 관여도의 매개효과를 검증하고자 서울 및 경기지역 어린이 전용 수영장 학부모 450명을 설문조사 하였으며, 그 중 430부의 자료를 SPSS 21.0과 AMOS 7.0 프로그램을 이용하여 요인분석, 상관관계분석, 구조방정식모형 분석을 실시하였다. 이러한 과정을 통해 도출된 결론은 다음과 같다. 첫째, 어린이 전용 수영장 서비스품질 장소요인, 가격요인, 프로그램요인, 시설요인, 지도자요인 중 시설요인이 관여도에 유의한 영향을 미치는 것으로 나타났다. 둘째, 어린이 전용 수영장 서비스품질 요인 중 프로그램요인과 시설요인이 만족에 유의한 영향을 미치는 것으로 나타났다. 셋째, 어린이 전용 수영장 관여도는 만족에 유의한 영향을 미치는 것으로 나타났다. 넷째, 서비스품질 시설요인의 만족에 대한 영향에서 관여도의 매개효과가 검증되었다.

• 전자공학회논문지
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• 제54권4호
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• pp.108-112
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• 2017

고 휘도 방전 램프는 높은 광 효율이 요구되는 다양한 조명 환경에 많이 사용된다. 특히 메탈할라이드 램프용 조명 램프의 경우 램프 안정기의 크기는 매우 중요한 요소이며 작으면 작을수록 좋다. 메탈할라이드 램프용 전자식 안정기는 전자기식 안정기에 비하여 에너지 효율과 크기 그리고 조명기의 무게 등의 측면에서 성능이 우수하다. 본 논문에서는 DSP를 이용하여 고효율, 소형 및 경량화가 가능하고 비용이 절감되고 역률이 높은 전자식 안정기를 제시하였다. 제시한 전자식 안정기는 다이오드 정류기와 역률 보상 제어 부스트 컨버터 그리고 하프 브릿지 인버터로 구성하였고 역율 보상 알고리즘과 안정기 제어 알고리즘은 TI사의 TMS320LF2406 CPU를 사용하여 구현하였고 실험을 통해 제시한 안정기의 유용성과 타당성을 검증하였다.

• 한국태양에너지학회 논문집
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• 제30권4호
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• pp.71-78
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• 2010

Investigation of the effective soil thermal conductivity(k) is the first step in designing the ground loop heat exchanger(borehole) of a geothermal heat pump system. The line source method is required by New and Renewable Energy Center of Korea Energy Management Corporation in analyzing data obtained from thermal response tests. Another important factor in designing the ground loop heat exchanger is the borehole thermal resistance($R_b$). There are two methods to evaluate $R_b$ : one is to use a line source method, and the other is to use a shape factor of the borehole. In this study, we demonstrated that the line source method produces better results than the shape factor method in evaluating $R_b$. This is because the borehole thermal resistance evaluated with the line source method characteristically reduces the temperature differences between an actual and a theoretical thermal behaviors of the borehole. Evaluation of $R_b$ requires soil volumetric heat capacity. However, the effect of the soil volumetric heat capacity on the borehole thermal resistance is very small. Therefore, it is possible to use a generally accepted average value of soil volumetric heat capacity($=2MJ/m^3{\cdot}K$) in the analysis. In this work, it is also shown that an acceptable range of the initial ignoring time should be in the range of 8~16hrs. Thus, a mean value of 12 hrs is recommended.

• Archives of Plastic Surgery
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• 제41권5호
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• pp.466-471
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• 2014

Background Bleeding can be a problem in wound debridement. In search for an effective hemostatic agent, we experimented with a chitosan film combined with the recombinant human epidermal growth factor (rh-EGF), hypothesizing that it would achieve effective hemostasis and simultaneously enhance arterial healing. Methods Forty-eight Sprague-Dawley rats were used, and 96 puncture wounds were made. The wounds were divided into the following four groups: treated with sterile gauze, treated with gelatin sponge, treated with chitosan, and treated with chitosan combined with rh-EGF. Immediate hemostasis was evaluated, and arterial healing was observed histologically. Results Groups B, C, and D showed a significant rate of immediate hemostasis as compared to group A (P<0.05), but there were no significant differences among groups B, C, and D. Histologically, only group D showed good continuity of the vessel wall after 1 week. It was the only group to show smooth muscle cell nuclei of the vessel wall. Conclusions We observed that chitosan has an effective hemostatic potential and the mix of rh-EGF and chitosan does not interfere with chitosan's hemostatic capabilities. We also identified enhanced healing of vessel walls when rh-EGF was added to chitosan. Further research based on these positive findings is needed to evaluate the potential use of this combination on difficult wounds like chronic diabetic ulcerations.

• Nuclear Engineering and Technology
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• 제14권3호
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• pp.138-147
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• 1982

열중성자로에 플루토늄의 재순환이 실현될 것에 대비하여 이의 해석을 위한 이론적인 기초를 수립하였다. 특히 상업적인 목적으로 플루토늄 재순환이 이루어질 때를 위하여 $UO_2$-PuO$_2$를 핵연료로 하는 균일격자 임계실험로에 대한 분석을 수행하였다. 이 목적을 위하여 GAM과 THERMOS에 이론적인 기초를 두고 $UO_2$-PuO$_2$계통의 해석에 적합한 이론을 가미하여 KARATE라는 이름의 단일세포격자코드를 개발하였다. KARATE에서 산출한 소수군 중성자 단면적과 확산이론 계산코드인 KIDD를 이용하여 임계실험로에 대한 유효증배계수를 계산하였다. 우리가 선정한 41개의 임계실험로에 대하여 유효증배계수의 평균치는 0.9997, 그 표준편차는 0.43%이었다. 이러한 결과는 KARATE/KIDD 전산체제가 $UO_2$-PuO$_2$를 핵연료로 하는 계통의 핵적 특성분석에 아주 유효하게 사용될 수 있다는 사실을 밝혀 준다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.258-264
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• 2012

The overall aim of this paper is to determine coupling loss factor of welding point between shell and cylinder using loss factor and structural loss factor. For this purpose, two kinds of loss factor were adopted. One is loss factor of each sub structure, another is structural loss factor based on the complex welded or assembled structure. Using these two parameters, it is possible to derive the coupling loss factor which represents characteristic condition of SEA theory. Coupling loss factor of conjunction in complex structure was expressed as power balance equation. The derived equation for a coupling loss factor has been simplified on the assumption of one way (uni-directional) power flow between multi-sub structures. Using these conditions, it is possible to find the equation of coupling loss factor expressed as above two loss factors. To check the effectiveness of above equation, this paper used two-stage application. The first approach was application between simple cylinder and shell. The next was adopted rotary compressor. Rotary compressor has three main conjunctions between shell and internal vibration part. This equation was applied to find out the optimum welding point with respect to reduce the noise propagation. It shows the effective tool to evaluate the coupling loss factor in complex structure.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 제17회 워크샵 및 추계학술대회
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• pp.182-190
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• 2005

This paper proposes central monitoring system(PVCMS) based on a TCP/IP network for effective integrating management about photovoltaic systems. We don't gain confidence the result of production simulation, because the output of PV system have many various environmental change factor. So if we can obtain real operated data about each sites and system types to use PVCMS, we can define the environment change factor to compare with simulation data. And this paper try to access about total management and data analysis methods of renewable energy through results analysis to synthesize of the operation.