• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.296-298
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• 2009

Ac-dc 싸이리스터 컨버터에서 전류기준값의 부호가 변화할 경우에 적분항 초기값을 통해 전류제어 과도특성을 개선하는 연구가 있었다. 이 논문에서는 전류기준값의 기울기에 변화가 있을 때 그 변화를 일으키기 위한 전압을 계산하고 그 값을 점호각 $\alpha$로 환산하여 시스템에 적용시켜 변곡점 부근에서의 전류제어 특성을 개선하는 방법을 제시하였다. 또한 전류기준값에 노이즈가 포함된 경우 LPF 유/무에 따른 특성변화와 노이즈가 포함되지 않은 경우 LPF 유/무에 따른 특성변화를 관찰하였다.

• Journal of Korea Society of Industrial Information Systems
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• v.18 no.4
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• pp.37-41
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• 2013

A balance maintain system of Stewart platform using AHRS(Attitude and Heading Reference System) sensor is introduced. The Stewart platform is used for controlling a standing plate to keep up horizontal level at any slopes. To know current leaned degrees, AHRS sensor is used. We made feed-back system that AHRS sensor sends current status and the Stewart platform revises top plate to be equilibrium state.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.104-109
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• 2002

본 논문에서는 기존의 BLDC전동기 구동방식에 의한 등가회로를 스위치가 off되는 상의 전류 및 역기전력을 고려한 새로운 토크모델을 이용하여 사다리꼴 역기전력을 가지는 BLDC전동기의 전환시 발생하는 토크맥동과 평균토크를 개선할 수 있는 새로운 토크맥동 저감방식을 제안하였다. BLDC전동기의 전기적인 등가모델 및 전류현상과 전환시 발생하는 토크맥동에 대하여 기술하였으며 발생토크의 변동의 원인이 되는 역기전력과 전류와의 관계를 고찰하였다. 이를 바탕으로 전환시 발생하는 토크맥동을 개선하기 위하여 스위칭 소자가 off 되는 상의 전류 및 역기전력을 고려한 상승상과 감쇄상의 전류기울기 제어 및 전환시점제어를 통한 토크맥동 저감방식을 제안하였으며, 전환시 발생하는 맥동토크의 저감효과에 대하여 해석하였다. 이의 검증을 위하여 MATLAB/Simulink를 이용하여 제안한 토크맥동 저감방식의 저감효과의 타당성을 검증하였다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.179-184
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• 2005

The daylight responsive dimming systems, which use daylight and automatically controls the brightness of electric lighting, according to the amount of daylight coming into the indoor, as well as always maintains target illuminance, is an energy saving type system. The control slope that decide the dimming percent for dimming ballast to run this system efficiently should be decided exactly. This research ran performance assessment applying daylight responsive dimming systems to actual space, and supplemented control slope in the sky condition for the elevation of system. Also we revaluated a system by modified control slope and compiled valid propriety and alternative for the elevation system.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.23-25
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• 2019

PSFB 컨버터(Phase Shift Full Bridge converter)는 다양한 전원장치에 응용되고 있다. 또한 빠른 응답과 1차 측 전류 피크의 불 평형을 방지하기 위해 PCMC(Peak Current Mode Control)를 적용해야 한다. 하지만 PCMC는 유효 시비율이 0.5 이상 일 때 저주파 발진이 일어나기 때문에 경사 보상 기법을 이용해 발진을 막아야 한다. 일반적으로 경사보상 기울기는 최댓값을 사용하기 때문에 전류 명령이 과 보상되며, 무효시비율 구간을 고려하지 않기 때문에 응답속도가 지연 되는 문제가 있다. 따라서 본 논문에서는 무효 시비율 구간을 고려한 하이브리드 피크-밸리 전류 밴드 제어를 통해 BUCK 컨버터와 동일한 응답 특성을 가지는 PSFB 컨버터 제어 기법을 제안한다. 제안하는 기법은 PSIM 시뮬레이션을 통해 검증되었다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.6
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• pp.1-7
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• 2011

This paper presents implementation and control of a two wheeled mobile robot system which consists of two systems, an inverted pendulum system and a mobile robot system. Control purpose is to regulate its balancing and navigation. The balancing robot has advantages of one point turning and robust balancing against disturbances from the ground. Simulation studies of local and global control methods are performed. Since the robot is implemented to have a symmetrical structure, simple linear control algorithms are used for balancing and navigation. Low cost sensors such as gyro and tilt sensor are fused together to detect the inclined angle. Experimental studies of following desired circular trajectory are conducted.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.5
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• pp.669-674
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• 2012

This study presents the remote control of a mobile robot using iPhone based on Wi-Fi communication. The paper proposes the following set of user interfaces : acceleration mode, arrow touch mode, and jog-shuttle mode. To evaluate the proposed three interfaces, a virtual robot is controlled in a monitor to follow a referenced trajectory using iPhone. In simulation, the standard deviation and summed errors are analysed for showing good and weak points of the proposed three interfaces. The proposed interface replace an additional remote controller requiring cost with a cellular phone. Results of an experiment show that the proposed interfaces can be effectively used for remote robot control.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.75-84
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• 2013

In this study, the patterns and characteristics according to gait cycle were analyzed using to EMG signals during walking, and analyzed in the time domain and frequency domain. The experiments was performed divide to level-ground walking and stair walking, and gait cycle was analysis by stance and swing. In the sagittal plane by using the tilt sensor measures the angle of the lower leg, and EMG was measured from the quadriceps and biceps femoris. The tilt of the lower leg was showed the biggest tilt at HS, and showed lowest value at TO. All in walking according to the gait cycle IEMG showed a specific pattern, and is expected useful to determine the gait cycle and kind. In the frequency domain analysis was using STFT on able to frequency analysis according to time, and using the tilt sensor was identify gait cycle. We analyzed also spectrum of the results of the STFT in all gait types, and recognized that stance had broad bandwidth than that of swing. Through this study, it was confirmed the possibility of judgment and analysis of the gait cycle using EMG and the tilt in the sagittal plane of the lower leg. When used it, can improve the quality of life of amputation patients

• Journal of Korea Multimedia Society
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• v.5 no.6
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• pp.609-615
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• 2002

In this paper, we propose a contrast for the improvement of multi-gray scale image on display system. The proposed method distinguishes a maximum value and a minimum value in input fields or frames. By this judgement, the improvement degree of image quality is decided. This method does not require field and frame memory. Moreover, its lower hardware complexity than conventional methods make it easy to apply this method for flat panel display(FPD) which requires real-time processing. And the contrast of input gray level can be controled flexibly by varying the weight the weight value which controls the contrast range. The proposed method gives an image by controlling weighting slope selectively at intervals according to the brightness-control algorithm and the type of image in the look-up table. The function of the proposed method has been verified through Synopsys VHDL and computer simulation. And its results show that the proposed method can improve the quality of image.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.495-498
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• 2017

As the number of tourist has been increased recently, the interest level in the carriers was elevated. Hence, the technologies on the carriers have been developed variously, and smart carriers are widely used. However, noises are occurred with multiple causes since smart carrier uses the speed control system by gradient sensor. Because of this, the possibility of wrong operation is high by abrupt operation or cumulative error. Therefore, FIR low pass filter was designed and applied in the gradient sensor to realize the strong sensing system against the noise so as to supplement the weaknesses of the existing system in this article.