• International Journal of Internet, Broadcasting and Communication
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• 제14권3호
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• pp.69-78
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• 2022

In this paper, we propose the new technique adopting power control to MIMO(multi-input multi-output)-OFDMA(orthogonal frequency division multiplexing Access) system with multi-beamformer. The proposed power controlling algorithm for MIMO-OFDMA allocates the transmitting power of each subcarrier based on the CSI(channel state information) and the interference signal. CSI is feedback from base station to mobile station to decide the transmitting power of each subcarrier. Through the proposed technique, we can control iteratively the transmitting power and update the weight of beamformer simultaneously. Therefore, the SNIR of each subcarrier become to converge the target SNIR and the beam is formed toward the desired direction. And the performance of MIMO-OFDMA system with the proposed approach is very improved. The improvement in bit error rate is investigated through computer simulation of a MIMO-OFDMA system with the proposed approach.

• 한국지능시스템학회논문지
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• 제21권5호
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• pp.602-608
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• 2011

본 논문에서는, 신경망을 이용한 뉴로 인터페이스 설계를 통해 논홀로노믹 이동 로봇을 제어하는 방법을 제시하였다. 특히, 가상의 마스터-슬레이브 로봇 개념을 이용하여, 부분적으로 안정된 마스터 로봇의 역 동적모델이 피드백-에러 학습법을 적용한 신경망을 통해 온라인으로 획득되도록 하였다. 이 피드백 제어기는 PD 보상기에 기초를 두고 있다. 온라인 학습을 위한 신경망은 입력층이 6개의 입력세포들($x_i$, i=1~6)로 구성되어있으며, 1개의 은닉층에는 2개의 은닉세포($o_j$, j=1~2), 출력층은 2개의 출력세포(${\tau}_k$, k=1~2)로 구성되었고, 신경망의 온라인 학습을 위하여 최소자승법에 의한 오류역전파 알고리즘을 이용하였다. 본 연구에서 개발된 뉴로 인터페이스의 경로추적제어에 관한 성능은 2-wheel 독립구동이 가능한 논홀로노믹 이동 로봇의 시뮬레이션으로 증명하였다.

• 센서학회지
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• 제24권2호
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• pp.131-136
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• 2015

This paper presents a wide dynamic range complementary metal oxide semiconductor (CMOS) image sensor with column capacitor and feedback structure. The designed circuit has been fabricated by using $0.18{\mu}m$ 1-poly 6-metal standard CMOS technology. This sensor has dual mode operation using combination of active pixel sensor (APS) and passive pixel sensor (PPS) structure. The proposed pixel operates in the APS mode for high-sensitivity in normal light intensity, while it operates in the PPS mode for low-sensitivity in high light intensity. The proposed PPS structure is consisted of a conventional PPS with column capacitor and feedback structure. The capacitance of column capacitor is changed by controlling the reference voltage using feedback structure. By using the proposed structure, it is possible to store more electric charge, which results in a wider dynamic range. The simulation and measurement results demonstrate wide dynamic range feature of the proposed PPS.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.147-150
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• 1996

This paper describes controller design and implementation method for controlling the temperature distribution in a thermal stratified wind tunnel(TSWT) by using a neural network algorithm. It is impossible to derive a mathematical model of the relation between heat inputs and temperature outputs in the test section of the TSWT governed by a nonlinear turbulent flow. Thus inverse neural network models with a multi layer perceptron structure are used in a feedforward control loop and feedback control loop to generate an arbitrary temperature distribution in the test section of the TSWT.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.45-49
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• 1988

This paper presents a centralized adaptive control scheme based on perturbation equations in the vicinity of a desired trajectory,which are used to design a feedback control about the desired trajectory. This adaptive control scheme reduces the manipulator control problem from a nonlinear control to controlling a linear control system about a desried trajectory. Computer simulation studies of a two-joint manipulator are performed on a IBM-PC to illustrate the performance of this adaptive control scheme.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.808-812
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• 1998

A new SPWM control method for Uninterrupted Power System(UPS) is presented. A triangle waveform is used as the reference signal. The desired SPWM control signal can be obtained more easily with a group of comparators. The output AC voltage can be regulated by controlling the lower reference and the upper reference of the comparators according to the feedback voltage. Basic principle, an actual circuit and the experimental results on a 500W UPS for computer system is discussed as an example.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 A
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• pp.392-394
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• 1999

In this paper, the vector of induction motor using as sensorless is described. Controlling through the estimation of input by slip, the speed controller wit control loops of torque control constant speed operation by the feedback of slip is composed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.389-391
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• 1996

A Hybrid technique is introduced in this paper for a manipulator with 2 DOF flexible links. The manipulator dynamics plus the actuator dynamics is controlled by taking force feedback for the end-effector of the link 2 while controlling the position of link I to control the position of the end-effector.

• 대한수학회지
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• 제35권1호
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• pp.135-148
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• 1998

We propose the new controls constructed via the second or direct method of Liapunov to solve the collision avoidance control problems for moving objects and a robot arm in the plane. We also explicate the controlling effect by the simulations.

• 한국정보과학회논문지:데이타베이스
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• 제32권4호
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• pp.362-371
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• 2005

멀티미디어 데이타베이스와 같은 고차원 응용에서 유사 색인과 검색은 어려운 문제이며, 특히, 다수의 특성을 함께 색인하는 경우에는 더욱 어렵다. 본 논문에서는 고차원 이미지 데이타베이스에서 복합 유사 질의 및 적합성 피드백을 효율적으로 처리하기 위한 새로운 색인 기법인 GB-색인을 제시한다. GB-색인은 각 특성 차원을 독립적으로 처리함으로써 다수의 특성과 다수의 질의 객체를 유연하게 제어한다. 아울러, 비트맵 색인을 통해 데이타베이스에 있는 모든 객체를 비트맵의 집합으로 표현하여 질의를 효율적으로 처리한다. GB-색인의 기술적인 주된 공헌은 다음과 같다: (1) 고차원 데이타를 위한 효율적인 색인, (2) 효율적인 복합 유사 질의 처리, (3) 적합성 피드백을 위한 분리형 질의의 효과적 처리. 실험 결과에 따르면 GB-색인은 순차 탐색 및 VA-파일에 비해 큰 성능 향상을 보였다.