• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.7
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• pp.87-94
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• 2015

Recently, renewable energy sources are under the spotlight. due to the depletion of fossil fuels and environmental problem for the carbon dioxide. Among them, research on the Photovoltaic System using solar energy systems has been actively conducted. In this paper, we propose boosting the insulated DC/DC converter topologies Applied to soft-switching methods used in photovoltaic PCS. The proposed topology is of a type that combines a series of full-bridge converter and a boost converter, a full bridge converter and applying the insulation and soft switching system, the output voltage boost stage is carried out for the boost control. The proposed circuit validity was verified through the PSIM simulation and 5kW PV PCS Prototype and experiments.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.151-154
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• 2004

To use the SLIM for servo system, the exact account of thrust about the initial speed is needed, but analyzing by equivalent circuit analyzing methode such as rotary induction motor, the error occurs because of the end effect. So, we applied the equivalent circuit considering the end effect of SLIM in this paper. The current control system is advanced the space vector pulse width modulation by using high arithmetic performance microprocessor such as DSP. In this paper, we use the dynamic characteristic analyzing methode that can calculate efficiently the end effect by using equivalent circuit methode in the operating SLIM system modeling and examine the output characteristics of SVPWM with PI controller.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.618-620
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• 2008

본 논문에서는 대기 오염 물질의 방출이 적고, 소음이 적은 환경 친화적인 Ni-MH전지를 독립형 태양광 가로등시스템에 적용하였으며 충방전제어기를 구성하여 출력특성을 고찰하였다. 출력특성을 고찰한 결과 충전 및 방전이 원활히 진행됨을 알 수 있었다. 그러나 충전시 정전압 충전방식을 사용하였고 태양 전지 출력측에 MPPT제어가 이루어 지지 않은 탓으로 태양전지 이용률이 떨어지며 화창한 날 태양전지의 등가 발전시간은 약 6시간에서 7시간 정도 나오지만 축전지는 오전 중에 충전이 완료되고 오후발전량은 모두 버리게 됨을 알 수 있었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.12-15
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• 1997

The FEM analysis and properties of a 10 Gbps LiNbO$_{3}$ optical modulator fabricated are discrobed. The driving voltage and -3㏈ bandwidth of this device were 5.5 V and 7㎓, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.16-19
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• 1997

We have investigated the optical properties of a Ti:LiNbO$_3$ optical waveguide which was fabricated by Ti-diffusion in a alto atmosphere, and propose an effective method of polishing waveguide. This method was regarded to be applicable to waveguide fabrications.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1206-1208
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• 2001

Direct torque control(DTC) of AC motor has the fast torque and flux dynamic responses even though it has very simple scheme to implement. DTC is also very simple in its implementation because it needs only two hysteresis comparators and switching vector table for both flux and torque control. The amplitude of hysteresis band greatly influences on the drive performance such as flux and torque ripple, switching frequency and current harmonics. Therefore, authors analysis flux and torque hysteresis bands is suggested considering switching frequency and harmonic distortion of currents.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.299-302
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• 2003

This study aims to apply and compare flood routing methods for irrigation reservoirs. In this research, three methods, which are the storage indication method(SIM), the mass curve method(MCM), the frog method(FM) were adopted and applied to two storm events of July $9{\sim}10\;and\;22{\sim}23$ of Donghwa-dam and its watershed located on Jangsoo-gun, Chunnam province. As the application results MCM showed the highest value at peak overflow and goodness-of-fit to the observed value, although the others also had similar value with the observed one. In analyzing lag time of peak between inflow and overflow MCM and SIM showed 7 hours, while FM showed 6 hours for the first storm event, and all three methods showed 3 hours for the second event.

• Journal of International Academy of Physical Therapy Research
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• v.6 no.2
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• pp.896-901
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• 2015

The effects of national gymnastics and brain gymnastics on brain activity were analyzed in 20 healthy university students. The students were assigned to either a national gymnastics group or a brain gymnastics group. Their frontal lobe activity was recorded before and after the exercise, and the resting, attention, and concentration indexes of brain waves were measured. The resting index significantly decreased and concentration index significantly increased(p<.05) after the exercise in both the national and brain gymnastics groups. However, the attention index significantly increased only after brain gymnastics, and, on the contrary, decreased after national gymnastics. These findings suggest that brain gymnastics is effective for improving attention.

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.1
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• pp.88-97
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• 2002

The purpose of this study was to evaluate a cases which was treated with magnetic attachments on the patients in edentulous mandible and maxilla. Author made magnetic overdenture for two patients and then clinical examination were used for evaluation of the function and change in retention during 30months. Patients showed difficulty in oral hygiene care at the beginning but they go used to it soon. It was effective in promotion of denture retention and stability and also gave patient emotionally uplifting psychologic state. This study suggest that magnetic attachment was effective for the treatment of patients presenting a few remaining teeth or teeth under severe caries or mobility.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.4
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• pp.444-451
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• 2001

The purpose of this study was to evaluate the rate of adherence of bacteria on various denture relining materials and to find out the effects of chitosan, when it was added to denture relining materials. Denture relining materials such as Tokuso rebase normal $set^{(R)}$, Mild $rebaron^{(R)}$, $Kooliner^{TM}$, and New $truliner^{TM}$ were used in this study. The adherence of Streptococcus mutans was studied on the surfaces in the denture relining materials with chitosan and in those without chitosan. When chitosan was added to M17 broth and MRS broth, the viable cell count of Streptococcus mutans was reduced. The viable cell count of Streptococcus mutans on the specimens decreased in the following order : Mild rebaron, Tokuso rebase normal set, and Newtruliner and Kooliner. The deture relining materials with chitosan showed a lower rate of adherence of Streptococcus mutans than those without chitosan.