• Journal of IKEEE
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• v.17 no.1
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• pp.77-82
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• 2013

In this paper, dc-dc buck converter controled by the peak current-mode pulse-width-modulation (PWM) presented. Based on the small-signal model, we propose the novel methods of the power stage and the systematic stability designs. To improve the reliability and performance, over-temperature and over-current protection circuits have been designed in the dc-dc converter systems. To prevent electrostatic An electrostatic discharge (ESD) protection circuit is proposed. The proposed dc-dc converter circuit exhibits low triggering voltage by using the gate-substrate biasing techniques. Throughout the circuit simulation, it confirms that the proposed ESD protection circuit has lower triggering voltage(4.1V) than that of conventional ggNMOS (8.2V). The circuit simulation is performed by Mathlab and HSPICE programs utilizing the 0.35um BCD (Bipolar-CMOS-DMOS) process parameters.

• Journal of Korea Entertainment Industry Association
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• v.14 no.8
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• pp.197-202
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• 2020

In this study, we investigate the effect of twenties female caffeine addiction on cardiorespiratory capacity. For this study, we divided 35 female students at H university into caffeine addict group(n=17) and none caffeine addict group(n=18). Measure maximal oxygen uptake, maximal energy consumption and METs using Cycle Ergometer to assess cardiac capacity. Measure peak inspiratory pressure, peak inspiratory flow rate, peak inspiratory capacity, average inspiratory pressure, average inspiratory flow rate, average inspiratory capacity using Power Breathe K5 to assess respiratory capacity. As a result, cardiac capacity showed a statistically significant decrease in maximal oxgen uptake and METs compared caffeine addict group to none caffeine addict group(p<.001). respiratory capacity showed a statistically significant decrease in peak inspiratory pressure(p<.05), peak inspiratory flow rate(p<.01), average inspiratory pressure(p<.01), average inspiratory flow rate(p<.01), compared caffeine addict group to none caffeine addict group. Combining the results of the study, we could see that caffeine addiction reduces the cardiorespiratory capacity in twenties female. Therefore, it could be used as a basis date to prevent caffeine addiction for twenties female.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.472-475
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• 2000

An balanced tapped inductors using RPPT (Regulated Peak Power Tracking) system is proposed. In the series/parallel PPT system battery charger and discharger are operating complementary. So they both can be combined into a single hardware block. Battery charger and dis-charger share same magnetic cores thus can be reduced core weights.

• ETRI Journal
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• v.6 no.4
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• pp.37-40
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• 1984

in the case of using SMES to shave the peak load with the isolated synchronous ge nerator- converter, the performance equations are derived. The commutation angle, the power angle, the field current, the storage energy and the power are derived by changing firing angle, that is, following the excitation velocity of SMES current. The output characteristics are computed by digital computer simulation.

• Proceedings of the KSPS conference
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• 2006.11a
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• pp.88-91
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• 2006

Steered response power(SRP) based algorithm uses a focused beamformer which steers the array to various locations and searches for a peak in output power to localize sound sources. SRP-PHAT, a phase transformed SRP, shows high accuracy, but requires a large amount of computation time. This paper proposes an algorithm that clusters search spaces in advance to reduce computation time of SRP based algorithms.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.10a
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• pp.285-287
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• 2008

This paper represents the electric power load leveling effect of the Light Control System(LCS). The lighting of typical mid-large commercial buildings is the major factor of daytime electric power consumption. Since the national peak power demand occurs in between 11:00 and 16:00, the dimming control of light can contribute the decrease of the power demand We will discuss the load leveling effect of dimming control with LCS.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.423-424
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• 2012

본 논문에서는 피크 전류 모드 제어를 적용한 플라이백 컨버터의 정확한 Control-to-Output Transfer Function을 제시한다. 기존 저주파 극점만으로 간략화 된 모델은 실제 디스크리트 모델(Discrete Model)과 소신호 해석에서 많은 차이를 보인다. 본 논문에서는 정확한 저주파 극점을 유도하고, PSIM을 통한 모의실험을 통해 제안된 모델에 대한 정확성을 검증한다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.1
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• pp.1-12
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• 1992

Generally, laser machines with high generated power can be developed by means of enhancing their mean power, since the enhancement of mean power exerts an influence on peripheral parameters and machining performance. In this research, we evaluate the various machining properties by the use of two machines which bear different mean power each other, so that we may study various effects of the enhancement of mean power. As a result, when the mean power comes to be enhanced to 75%, we obtain the increase of output energy up to 69% and of peak power more than 95%, and also obtain almost twice of the cutting speed. Moreover we find the fact that if the test pieces have enough thickness in contrast with output energy, the pulse frequency moves toward the frequency bandwidth which takes proportion to the cutting speed mas well as to the amount of material removal per unit time. In addition it is finally obtained that the laser machine with high output power yields small taper degrees at kerf parts, while it has large cutting widiths and dross lengths.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.8
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• pp.70-76
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• 2012

In this paper, we propose a power allocation scheme of the unlicensed user based on orthogonal frequency division multiplexing (OFDM) in the TV white space (TVWS). Power constraints in TVWS should be satisfied in the time domain. However, because OFDM has high PAPR (peak-to-average power ratio), it is difficult to satisfy power constraints of TVWS in the time domain. Furthermore, the conventional power allocation schemes cannot be generally applied to unlicensed user in TVWS. Therefore, we propose a power allocation scheme to satisfy power constraints of TVWS by reducing PAPR in the time domain. In addition, we analyze the capacity of the unlicensed user based on OFDM in a closed form. Based on the capacity analysis, as the number of subcarriers decreases, the capacity can be enhanced. In simulation results, we show that the capacity of the unlicensed user increases, as the number of subcarriers decreases and the mean of the channel between the transmitter and the receiver of the unlicensed user increases.

• The Transactions of the Korean Institute of Power Electronics
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• v.2 no.1
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• pp.33-38
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• 1997

Generally, various semiconductor switching devices for power systems are used in battery chargers for electric vehicle. When these used, it takes the problems of transient-current or distortion of waveforms in power systems near by battery chargers because of harmonics and large peak-current, low power factor, etc., caused by the non-linearity of these devices. Recently, power factor control, line current peak-cut, harmonics reduction which was ignored in past is more and more important. In this paper, to solve those problems we will improve the characteristics of voltage rising and propose the high power factor converter circuit for battery chargers. Our proposed system convert commutated voltage to AC resonant wave in high frequency inverter and rectify the link voltages passed high-frequency transformer and transfer the DC voltages. Especially, the effect using these converter system can be improved very large by power factor control and we have to verify the possibilities of improvement through the experiment of Pb-Acid battery application.