• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.4
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• pp.372-380
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• 2004

This paper proposes a single-power-stage high frequency resonant AC-DC converter with high power factor using ZVS(Zero Voltage Switching), and integrates a conventional converter with two stage into single stage converter. Input power factor is possible to be improved as a high power factor because inductor for power factor correction(PFC) is connected in input and converter is operated in discontinued current mode(DCM) with constant duty cycle and variable switching frequency. The conventional converter with two stage need to add a switch in order to control a power factor, but single stage converter have a advantage that system is simple and cost is down, confidence is improved, etc. This paper described a operation principle and characteristic analysis for single stage AC-DC converter with high power factor and have evaluated characteristic values by using normalized parameter. We make a experimental equipment using MOSFET as a switching device on the basis of characteristic values obtained from characteristic evaluations and we conform a rightfulness of theoretical analysis by comparing theoretical waveforms and experimental waveforms.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.357-360
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• 2013

A 1.8V 2-Gb/s scalable low voltage signaling (SLVS) transmitter (TX) is designed for mobile applications requiring high speed and low power consumption. It consists of 4-lane TX for data transmission, 1-lane TX for a source synchronous clocking, and a 8-phase clock generator. The proposed SLVS TX has the scaling voltage swing from 50 mV to 650 mV and supports a high speed (HS) mode and a low power (LP) mode. An output impedance calibration scheme for the SVLS TX is proposed to improve the signal integrity. The proposed SLVS TX is implemented by using a $0.18-{\mu}m$ 1-poly 6-metal CMOS with a 1.8V supply. The simulated data jitter of the implemented SLVS TX is about 8.04 ps at the data rate of 2-Gbps. The area and power consumption of the 1-lane of the proposed SLVS TX are $422{\times}474{\mu}m^2$ and 5.35 mW/Gb/s, respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.490-492
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• 2010

A swing level controlled voltage-mode transmitter is proposed to support a stub series-terminated logic channel with center-tapped termination. This transmitter provides a swing level control to support the diagnostic mode and improve the signal integrity in the absence of the destination termination. By using the variable parallel termination, the proposed transmitter maintains the constant output impedance of the source termination while the swing level is controlled. Also, the series termination using an external resistor is used to reduce the impedance mismatch effect due to the parasitic components of the capacitor and inductor. To verify the proposed transmitter, the voltage-mode driver, which provides eight swing levels with the constant output impedance of about $50{\Omega}$, was implemented using a 70nm 1-poly 3-metal DRAM process with a 1.5V supply. The jitter reduction of 54% was measured with the swing level controlled voltage-mode driver in the absence of the destination termination at 1.6-Gb/s.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.3327-3335
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• 2014

In this study, comparison works have been performed for single-stage and multi-stage refrigeration cycle using propane as a refrigerant in order to cool down the natural gas stream. A comparative analysis has been performed for a single, two, three and four stage refrigeration cycle using propane as a refrigerant for cooling the natural gas stream. For the simulation, natural gas feedstock properties supplied by KOGAS were utilized and Peng-Robinson equation of state model was used. As the number of compression stages increase, the condenser heat duty is decreased. The refrigeration heat duty for a four-stage refrigeration cycle is decreased by 20.36% compared to that for a single-stage refrigeration cycle. Moreover, the total refrigerant circulation rate for a four-stage refrigeration system is was reduced by 14.53% compared to the single stage refrigeration cycle. The total compression power for a four-stage compression was reduced by 41.61% compared to the single stage compression.

• Korean Journal of Veterinary Service
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• v.42 no.1
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• pp.31-37
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• 2019

There have been a total tenth FMD outbreaks in Korea and for the first time, type O and A were detected simultaneously in 2017, which led to difficulties in FMD control. For the effective prevention of FMD, the importance of discrimination of serotypes became greater. Therefore, the most urgent requirement in case of FMD outbreak is differential diagnosis of serotypes. In this study, we developed a PNA probe-mediated multiplex real-time reverse transcription-polymerase chain reaction (rRT-PCR) assay using the peptide nucleic acid (PNA) probe, which is known to be stable to nucleotide mutation and that could specifically detect the all FMDV serotype A, FMDVA Yeoncheon strain which was occurred in Korea in 2017, and FMDV A viruses shown 96% similarity with FMDVA/Yeoncheon strain, at the same time. Therefore, It is believed that the newly introduced FMDVA will be effectively diagnosed using the PNA probe multiplex RT-PCR developed in this study, and ultimately contribute to the prevention of FMD.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.153-154
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• 2016

기존 단상 AC 전원용 LLC 컨버터는 250W의 조건에서는 PFC (Power-Factor Correction, 약칭 PFC) 회로를 채용하는 것이 일반적이다. 그러나 이러한 2단 전력단 형태의 회로는 자성체(인덕터) 및 제어기의 사용이 필수적이며, 이는 회로 부피 및 원가 상승의 주요한 원인이 된다. 본 논문은 DM Choke와 차지 펌프를 적용해 회로의 역률을 개선하는 방안을 제안하여, PFC Stage를 삭제하고 역률 개선 기능을 통합한 단일 전력단 LLC 컨버터를 제안한다. 본 논문에서는 제안한 회로를 이론적으로 분석하고, 190W급의 시작품을 이용한 실험적 분석을 통해 실용 가능성을 검증하였다.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.4
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• pp.325-330
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• 2001

It has been realized that the results of circuit level simulation of neural networks, used for optimization problems, arc much different from those of algorism level simulation. In other words, the outputs converges asymptotically as time elapes, however, the input convergence depends on the value of parasitic conductance connected between input node and ground. Also, this conductance affects system performance. This paper discusses the influence of input conductance on the convergece of the continuous Hopfield neural networks. The convergence has been analyzed for the input and output nodes of neurons. Also, the characteristics of equilibrium points has been analyzed depending on different values of the input conductance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.917-918
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• 2008

국제표준화기구의 각 국의 표준화활동 정책동향 연구를 통하여 각 국이 왜 의장단에 진출하여 활동할려고 하는지, 이로 인한 자국의 이익이 무엇인지, 기술 반영은 어느 정도 되고 있는지, 표준화의 주도적 역할을 과연 의장단 진출로 인하여 반영은 할 수 있는지 등에 대해 논의하고자 한다. 우리나라는 지난 1987년이후 의장단 진출을 위해 국제표준화기구의 연구위원회 회의 등을 한국에서 수차례 유치하는 등 정부의 많은 노력 끝에 국내에서 그동안 각 분야별 전문가들이 국제기구에의 의장단에 진출하여 표준화 활동을 하고 있다. 지난 터키 회의에서 ITU-T 사무총장 진출을 하였으나, 좌절되었고 최근 소련에서 개최된 3GPP에서 한국이 부의장에 당선되는 등 최근의 의장단 활동이 두드러지게 나타나고 있다. 이번 WTSA에서는 25명의 의장단이 진출할 예정이다. 이로 인하여 향후 표준화활동의 지속적인 활동으로 정보통신 분야에서의 기술적 이익이 반영되었으면 한다.

• 프린팅코리아
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• v.11 no.1
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• pp.74-79
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• 2012

대한인쇄문화협회(회장 김남수)는 구랍 1일부터 3일까지 3일간에 걸쳐 문화체육관광부의 국고 지원을 받아 인쇄물 신규 해외시장 개척과 선진국의 고품질고부가가치 인쇄시장을 파악하고 공략하기 위해 '2011 일본시장개척단'을 파견하여 상담회를 도쿄 신주쿠에 위치한 미시바빌딩에서 개최했다. 이번 일본시장개척단의 파견은 정부사업으로 운영되고 있는 인쇄수출센터가 추진한 주요사업의 하나로 대한인쇄문화협회 김남수 회장을 단장으로 동방인쇄공사, 두성칼라, 새한문화사, 아시아프린팅, 영인정보시스템, 청아문화사, 청우, 타라티피에스의 8개사, 13명을 비롯하여 인쇄문화협회의 임직원을 포함한 16명으로 구성되었으며 일본에서는 현지 스텝 13명이 추가적으로 시장개척단을 지원했다. 이번 개척단은 수출시장에 처음으로 관심을 갖고 참여하는 업체와 기존의 수출경험이 많은 업체들이 비슷한 비율로 구성이 되어 많은 경험과 패기가 조화를 이룬 가운데 경쟁보다는 서로를 보완할 수 있는 분위기를 조성한 시장개척단이라는 평가를 받았다.

• Journal of Power System Engineering
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• v.8 no.4
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• pp.5-10
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• 2004

본 연구는 단기통 4행정 기관의 배기단의 형상에 따른 실험과 수치해석이 소개되었다. 흡 배기 밸브가 작동하고 있고, 주요한 배기단의 변수로는 배기단 직경이 적용이 되었다. 실험결과로는 배기단의 직경에 따라 배기 압력은 많은 영향을 받았는 것으로 나타났다. 배기단의 직경이 감소하였을때, 배기압력파의 진폭과 파수가 증가되었다. 배기단의 직경이 증가 하였을 때, 배기압력파의 진폭이 감소하였다. 직경이 22mm 일 때의 소음의 주파수 분석이 16mm와 28mm 보다 진폭이 작게 나타났다.