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직렬형 PWM 인버터를 이용한 동적전압보상기에 관한 연구
배정환,한병문,한경희,김희중 명지대학교 대학원 1997 대학원논문집 Vol.1 No.-
This paper presents a novel compensation method for the voltage sag problem for a critical load. This method is able to restore the supply voltage to the original magnitude and shape by injecting the vector diffence between the desired voltage and the actual voltage. The proposed system consists of a dc energy storage device, dc-ac converter, and a coupling transformer to inject the output of the inverter in series with the line. It can make up for the weakness of UPS and SPS. The operation of this system is verified by the computer simulation with EMTP code and experimental work with a scaled model. The advantages of this new system over the existing system are the fast reaction time and the low compensation energy in operation.
농업기계에 대한 인식도 : 농업계 고등학생을 중심으로 Focusing on the Agricultural High School Students
김정환,김민배 순천대학교 과학교육연구소 2001 科學과 敎育 Vol.9 No.-
The purpose of this study was to analyze the degree of an agricultural high school students’ recognition to the farm machinery according to their parent’s farming, sex, department and grade. This project surveyed 680 agricultural high school students at the jollanam-do. The data were analysed using SAS pc program. the major findings were as follows: 1. The degree of recognition to the farm machinery of paddy fields was high, but that to the farm machinery of livestock, up land fields and gorticulture was low. 2. The 31.6% of students showed dissatisfaction at the farm machinery. The first reason for this was that content of textbook was difficult and the second was that the number of the practice machine was little. 3. Concerning girl students’ reaction to farm machinery education, 50.2% students showed positive reaction. In the other hands, boy students showed more positive reaction than girl students.
부트스트랩 회로와 차지 펌프 회로를 이용한 플로팅 스위치의 음 전원 공급 방법에 대한 연구
배정환(Joung-Hwan Bae),이종무(Jong-Mu Lee),원충연(Chung-Yuen Won) 한국조명·전기설비학회 2017 조명·전기설비학회논문지 Vol.31 No.7
The unipolar gate driving method provides a low cost and simple solution for inverter system design. However, the unipolar gate driving can cause issues like ‘parasitic oscillation’ during turn-on of power switches and ‘unintended parasitic turn-on’ caused by the Miller-effect of power semiconductors. Hence the maximum value of gate resistance has to be limited. The proposed bootstrap circuit can generate a negative gate voltage with minimal increase of components. For this purpose a charge-pump circuitry is merged with a standard bootstrap topology which can generate a negative as well as a positive gate voltage for floating switches without additional isolated power supply.
서버용 650Watt 고효율 파워 서플라이 설계 방안 연구
배정환(Joung-Hwan Bae),이종무(Jong-Mu Lee),원충연(Chung-Yuen Won) 한국조명·전기설비학회 2017 조명·전기설비학회논문지 Vol.31 No.6
This paper proposed highly efficiency PSU(Power Supply Unit) using dual boost PFC circuit, LLC resonant converter, and Buck converter. In order to minimize the power conversion loss, PFC circuit selects Bridgeless PFC Dual Boost type using two switching elements and two SiC diodes and minimizes loss by using synchronous rectifier switching method. Using these power topologies helped PSU to meet up to 92% power efficiency and it made a low current and voltage ripple. Furthermore, the proposed method could stably supply the 3.3V and 5V from 12V for network system. In this paper the converter design and loss reduction method were proposed and the whole circuit had designed into 650W rated power. The theories and power efficiency of PSU were confirmed by simulation and experiment.
USN기반의 농업·농촌시설의 돌발재해 경보감지체계 개발
배연정 ( Yeon-joung Bae ),김성필 ( Seong-pil Kim ),배승종 ( Seung-jong Bae ),김학관 ( Hak-kwan Kim ),서일환 ( Il-hwan Seo ),김수진 ( Soo-jin Kim ),배원길 ( Won-gil Bae ) 한국농공학회 2014 한국농공학회 학술대회초록집 Vol.2014 No.-
우리나라의 재해연보를 통해 산사태의 발생 및 피해 형태를 분석하면 대부분 돌발홍수에 의해 사면 내에 유로가 발생하고 이 유로를 따라 토석류가 무너져 내리는 형태로 진행됨을 알 수 있다. 일반적으로 우리나라에 설치된 산사태·토석류 감지 및 돌발홍수 감지장비는 초기투자비 및 유지관리에 막대한 비용이 소요되며, 특히 우리나라 농촌 및 산악지역을 감안할 경우 넓은 지역에 대해 조밀한 계측 센서의 설치가 필요하므로 현재까지의 개발되어 적용하고 있는 계측센서 및 모니터링 체계를 적용하기가 곤란하다. 최근 정보통신기술이 발전하고 스마트-센서 관련 시장이 확대되면서 가속도센서, 자이로센서, 압력센서, 온도센서 등이 소형화되고 가격이 저렴해짐에 따라 기존 고가의 경사계, 간극수압계, 토양수분계를 대체할 수 있는 기술이 개발되고 있다. 또한 USN(Ubiquitors Sensor Network)과 같은 무선통신기술의 개발로 농촌지역과 같은 광범위한 감시체계를 구축해야 하는 지역에서 이용할 수 있는 센서-네크워크 기술이 개발되고 있다. 이에 본 연구에서는 이와 같은 무선 통신 인프라를 바탕으로 센서-네트워크를 이용하여 농업·농촌시설의 현장맞춤형 돌발재해 경보감지체계를 개발하고자 한다. 이는 산지재해 감지 무선센서 및 하천 수위센서를 개발하고, 무선으로 정보를 수집하는 게이트웨이를 경유하여 중앙의 정보수집센터로 수집 및 분석되며, 최종적으로는 지역주민들에게 사이렌 및 문자메시지 전송 등의 다양한 매체를 통하여 조기경보를 달성할 수 있는 체계를 구축하고자 한다.
배연정 ( Yeon Joung Bae ),배승종 ( Seung Jong Bae ),서일환 ( Il Hwan Seo ),서교 ( Kyo Seo ),이정재 ( Jeong Jae Lee ),김건엽 ( Gun Yeob Kim ) 한국농촌계획학회 2013 농촌계획 Vol.19 No.4
Analysis and evaluation of uncertainty is adopting the advanced methodology among the methods for greenhouse gas emission assessment that was defined in GPS2000 (Good practice guideline 2000) and GPG-LULUCF (GPG Land Use, Land-Use Change and Forestry). In 2006 IPCC guideline, two approaches are suggested to explain the uncertainty for each section with a national net emission and a prediction value on uncertainty as follows; 1) Spread sheet calculation based on the error propagation algorithm that was simplified with some assumptions, and 2) Monte carlo simulation that can be utilized in general purposes. There are few researches on the agricultural field including greenhouse gas emission that is generated from livestock and cultivation lands due to lack of information for statistic data, emission coefficient, and complicated emission formula. The main objective of this study is to suggest an evaluation method for the uncertainty of greenhouse gas emission in agricultural field by means of intercomparison of the prediction value on uncertainties which were estimated by spread sheet calculation and monte carlo simulation. A statistic analysis for probability density function for uncertainty of emission rate was carried out by targeting livestock intestinal fermentation, excrements treatment, and direct/indirect emission from agricultural lands and rice cultivation. It was suggested to minimize uncertainty by means of extraction of emission coefficient according to each targeting section.
A Switching Technique for Common Mode Voltage Reduction of 2-Level Inverter
Yun,Hwan-Kyun,Kim,Lee-Hun,Kim,Jun-Ho,Won,Chung-Yuen,Choi,Gi-Su,Bae,Joung-Hwan 성균관대학교 2002 학술회의지원논문목록집 Vol.2002 No.-
Much attention has given to EMI effects created by variable speed ac drive system. This paper focuses on the switching technique to mitigate common mode voltage. Zero switching states of inverter control invoke large common made voltage. Using inversed carrier wave, zero switching states are removed. In addition, proposed technique is easy to apply to existing 2-level inverter design. And common mode mitigation technique for sinusoidal PWM is also presented. Proposed switching technique is implemented with a 2.2kw 1735rpm induction motor.
과배란유도시 난포성숙을 유도시키는 GnRH Agonist가 성선자극 및 호르몬 분비에 미치는 영향에 관한 연구
김중환,이상훈,배도환 중앙대학교 의과대학 의과학연구소 1992 中央醫大誌 Vol.17 No.3
Gonadotropin medications have been used successfully for three decades to stimulate ovarian follicular development in anovulatory patients and , more recently, in normal ovulatory women for assisted reproduction. In these patients, endogenous luteinizing hormone(LH) surge infrequently occureed and therefore the administration of human chorionic gonadotropin(hGG) is required to induce oocyte maturation and ovulation. In spontaneous ovulatory cycle, there is a surge of both luteinzing hormone and follicle stimulation hormone(FSH) at midcycle. But, hCG possesses mainly LH-like activity. In addition, hCG continues to stiumlate the follicles for days after ovulation has been completed due to its long half-life. The objective of this study was to evaluate the efficacy of Gonadotropin releasing hormone(Gn고) agonist to trigger the final follicular maturation in hormone secretions during the ovarian stiumlation. A single dose of decapepty 0.1mg subcutaneously were administered to 40 cycles and 10,000 IU hCG were intramuscularly administered to 38 cycles for triggering the final maturation of oocytes. Both groups underwent identical ovarian stimulation protocol and cycle monitoring. GnRH agonist effectively triggered LH and FSH surge, and which duration was similar that of spontaneous menstrual cycle. In contrast hCG triggered LH surge only, and which duration was longer than that of spontaneous menstrual cycle. No differences were observed in mean serum E_2 and progesterone concentration. Mature oocytes were recovered in all patients. In conclusion, single dose of GnRH-a is able to trigger and adequate midcycle LH/FSH surge, resulting n adequate oocyte maturation and fertilization.