• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.348-350
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• 1994

In this paper, bi-directional buck-boost DC-DC converter for bus regulation system is presented. This converter which has one buck and one boost topology achieves bi-directional power flow using a common power inductor and alternative power switches. By connecting the battery to bus line, it can be regulated to bus voltage and charged the battery alternatively. And as an application, a mode controller is adopted to the converter.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.302-304
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• 2005

본 논문에서는 입력단 역률제어 및 고조파 전류억제를 위해 PWM 컨버터를 이용하는 3상 UPS에서 직류측을 공통으로 연결하여 하나의 배터리 유닛만으로 병렬 UPS운전이 가능한 공통 배터리 운전에 대해 기술한다. 직류측을 공통으로 이용함으로써 PWM 컨버터 간에 흐를 수 있는 순환전류를 없애기 위한 제어기를 제안하고 실험을 통해 제안한 방법의 타당성을 검토한다.

• Journal of Applied Reliability
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• v.9 no.3
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• pp.249-258
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• 2009

The measure of common-mode current on a cable can be closely correlate to the radiated emissions from the cable. This paper describes that to use the conducted emissions measurement method for calculating radiated emissions and compares them the measured radiated measurement results. For that the LISN which cover the radiated emissions frequency was developed.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.384-385
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• 2019

본 논문에서는 단상 컨버터/3상 인버터 시스템에서 공통모드 전압 저감을 위한 PWM 기법을 제안한다. 컨버터/인버터 시스템은 스위칭에 의한 공통모드 전압으로 인해 전동기의 누설전류와 절연파괴 등의 문제가 발생할 수 있다. 이에 본 논문에서는 영전압벡터 인가시간에 따라 유효전압벡터의 위치를 선정하여 공통모드 전압을 저감하는 방법에 대해 제안한다. 모의실험을 통하여 제안된 기법의 효용성을 검증하였다.

• Journal of Sasang Constitutional Medicine
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• v.23 no.2
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• pp.218-229
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• 2011

1. Objectives: This study is to investigate the relationship between Intima Media Thickness(IMT) of common carotid artery and Sasang Constitution. 2. Methods: 839 persons, over 40 years old, participated in community-based cohort of Korea Genome and Epiedemiology Study (KOGES) in Wonju City and Pyeongchang City of South Korea from June 2006 to February 2008. The diagnosis of Common carotid Intima Media Thickness was evaluated by B Mode ultrasonography, cardiovascular risk factors were checked using questionnaire and blood samples. Constitution was verified by a Sasang constitution specialist according to the results of PSSC(Phonetic System for Sasang Constitution), facial photos and a simplified Sasang constitutional questionnaire. Multiple regression analysis and logistic regression analysis were performed with SPSS. 3. Results: There were significantly high values in waist circumference, fasting blood sugar, systolic blood pressure, diastolic blood pressure, triglyceride, HOMA-IR and hsCRP in Taeeumin and low in HDL-cholesterol and adiponectin in Taeeumin. There were significantly high value in Common Carotid Intima Media Thickness in Taeeumin. Age was the significant cardiovascular risk factor irrespective of Sasang constitution in all participants. There was a positive correlation between smoking and Soyangin in all participants and men. There were positive correlations between LDL-cholesterol, BMI and Taeeumin in all participants and men. There were positive correlations between hsCRP and Soeumin in all participants and men. There was significantly high odds ratio of Taeeumin over Soeumin in common carotid Intima Media Thickness. 4. Conclusions: Regimens on cardiovascular diseases should be considered according to Sasang constitution. There are more sensitive risk factor in each constitution; smoking in Soyangin, LDL-cholesterol and BMI in Taeeumin, hsCRP in Soeumin.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.10
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• pp.885-894
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• 2015

In this paper, it can be applied to a walkie-talkie, the RFID / USN 920 MHz band(917~923.5 MHz) and WiFi 2.4GHz band(2.4~2.483 5GHz) return loss is 10 dB over the band, on-board dual band with omni-directional radiation characteristics is proposed. The basic structure designed antenna is used meander monopole antenna. It was used as double stubs and tabs for antenna designs that meet the criteria proposed. The double stub and the tab affects the reactance of the antenna to form a common-mode and differential-mode in the stub to improve the antenna characteristics and return loss in the bandwidth, gain and radiation characteristics. The system size of walkie-talkie is $52{\times}77mm^2$, the size of the antenna is limited to $52{\times}15mm^2$, the thickness of FR4 dielectric substrate is 0.8 mm, FR4 dielectric constant 4.4 is used. For experimental results, the return loss is measured more than 10 dB, the maximum gain is measured 1.95 dB, the maximum bandwidth is measured 360 MHz, the radiation characteristic is measured omni-directional. By a walkie-talkie terminal design applying the results of the paper, the handset's price competitiveness and production efficiency can be improved.

• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.2
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• pp.79-85
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• 2008

It is important to consider the life of battery and low power operation for various wireless communications. Thus, Analog current-mode signal processing with SI circuit has been taken notice of in designing the LSI for wireless communications. However, in current mode signal processsing, current memory circuit has a problem called clock-feedthrough. In this paper, we examine the connection of CMOS switch that is the common solution of clock-feedthrough and calculate the relation of width between CMOS switch for design methodology for improvement of current memory. As a result of simulation, when the width of memory MOS is 20um, ratio of input current and bias current is 0.3, the width relation in CMOS switch is obtained with $W_{Mp}=5.62W_{Mn}+1.6$, for the nMOS width of 2~6um in CMOS switch. And from the same simulation condition, it is obtained with $W_{Mp}=2.05W_{Mn}+23$ for the nMOS width of 6~10um in CMOS switch. Then the defined width relation of MOS transistor will be useful guidance in design for improvement of current memory.

• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.66-74
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• 1997

fMRI, functional MRI introduced receently appears based on the gradient echo technique which is sensitive to the field inhomogeneity developed due to the local susceptibility changes of blood oxygenation and deoxygenation. There has been many variants of the basic gradient echo sequence which is sensitive to the local inhomogeniety, among others such as GRASS or SSFP to EPISTAR are the most commonly used gradient echo techniques. Common to all these gradient echo techniques is that the signal due to the susceptibility effects is generally decreased with increasing inhomogeneity due to the $T2^{*}$ effect or conventionally konwn as blood oxygenation level dependent(BOLD) effect. It is, also found that the BOLD sensitivity is also dependent on the imaging modes, namely whether the imaging is in axial, or coronal or sagittal mode as well as the directions of the vessels against the main magnetic field. We have, therefore, launched a systematic study of imaging mode dependent signal change or BOLD sensitivity as well as the signal changes due tothe tilting angle of the imaging planes. Study has been made for both TRFGE sequence and CGE sequence to compare the distinctions of the each mode since each technique has different sensitivity againsst susceptibility effect. Method of computation and both the computer simulations and their corresponding experimental results are presented.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.49-58
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• 2014

A low-swing differential near-ground signaling (NGS) transceiver for low-power high-speed mobile I/O interface is presented. The proposed transmitter adopts an on-chip regulated programmable-swing voltage-mode driver and a pre-driver with asymmetric rising/falling time. The proposed receiver utilizes a new multiple gain-path differential amplifier with feed-forward capacitors that boost high-frequency gain. Also, the receiver incorporates a new adaptive bias generator to compensate the input common-mode variation due to the variable output swing of the transmitter and to minimize the current mismatch of the receiver's input stage amplifier. The use of the new simple and effective impedance matching techniques applied in the transmitter and receiver results in good signal integrity and high power efficiency. The proposed transceiver designed in a 65-nm CMOS technology achieves a data rate of 13 Gbps/channel and 0.3 pJ/bit (= 0.3 mW/Gbps) high power efficiency over a 10 cm FR4 printed circuit board.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.9
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• pp.872-875
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• 2016

In this paper, the turnstile junction-based Ortho-Mode Transducer(OMT) is designed and manufactured. It is usually well-known that turnstile junctions have symmetry structure of waveguide so the higher order modes, which occurs inside the waveguide, can be cancelled. Because of these symmetrical properties, the turnstile junction-based OMTs have merits like high transmission and low return loss characteristic in broadband and two different modes propagate orthogonally in common port resulting in the fully realization of double polarization. The designed OMT has the application of Radar Seeker and operates in W-band(94 GHz), the millimeter wave frequency. The average of return loss value of manufactured OMT is lower than -20 dB and it has bandwidth characteristic of over 500 MHz.