• 한국인쇄학회지
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• 제10권1호
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• pp.35-54
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• 1992

Direct electrostatic coating method is simple, low cost and environmentally useful method. We are investigated on the coating of carrier transfer polymer layer on the carrier generate inorganic pigment layer using direct electrostatic coating method. The sample was obtained electrostatic deposite layer by fusing and calendering on the copper phthalocyanine. we could be found several polymer thin film shows good bond properties between film and pigment layer.

• 한국항해항만학회지
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• 제35권8호
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• pp.643-647
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• 2011

이 논문에서는 수중음향통신의 성능 저해 요소 가운데 하나인 다중경로로 인한 인접 심벌간의 간섭(Inter-Symbol Interference)을 극복하기 위하여 직접 수열 대역확산(Direct Sequence Spread Spectrum) 기법의 적용성에 관해 연구하였다. 직접 수열 대역확산 방식은 육상이동통신 분야에서는 이미 널리 적용되고 있으나 수중음향통신에서는 상대적으로 적은 관심을 받았다. 이에 그 적용성을 검증하기 위해 실제 수중 채널에서 수집한 채널 응답 함수를 이용하여 모의실험을 수행한 결과 일반적인 QPSK (Quadrature Phase Shift Keying) 기법의 경우 BER(Bit Error Rate)이 $6.73{\times}10^{-3}$이였으며, 직접 수열 대역확산기법이 적용된 경우 BER이 $1.14{\times}10^{-1}$으로 일반적인 QPSK에 비해 향상된 성능을 나타내는 것을 확인할 수 있었다. 근거리 해상 실험을 수행한 결과 일반적인 QPSK 기법의 경우 전송률 1 kbps에서 BER이 $3.19{\times}10^{-1}$이였으며, 직접 수열 대역확산 기법이 적용된 경우 BER이 $5.17{\times}10^{-4}$이었다.

• International Journal of Control, Automation, and Systems
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• 제6권5호
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• pp.660-669
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• 2008

This paper presents a new carrier based pulse-width modulation (PWM) method for matrix converters. By using the concept of average over one switching period, the modulation algorithm and the required equations are derived to synthesize the desired output voltage and to achieve the controlled input power factor. The proposed method uses a continuous carrier and the predetermined duty ratio signals to directly generate the gating signals and, thus, is referred to as "direct duty ratio PWM (DDPWM)". The feasibility and validity of the proposed method were verified by simulation and experiment.

• 한국정보통신학회논문지
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• 제4권3호
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• pp.653-660
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• 2000

본 논문에서는 대역확산 통신을 위하여 웨이브렛 패킷 영역에서 다중적응필터뱅크를 이용하여 간섭신호를 제거할 수 있는 적응간섭제거기를 제안하고 Monte-Carlo 시뮬레이션을 이용하여 AWGN과 간섭채널에서 LMS와 RLS 적응알고리즘이 적용된 간섭제거기에 따른 대역확산통신시스템의 성능을 분석하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.312-315
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• 2003

The paper presents a small. unmanned remote controlled probing ship that can reduce the cost for acquiring data of marine and coastal environments. The control system is composed of three microprocessors. one is for overall mission control. another for control of propulsion motors. and the other for sensor operation. For communication system, we adopt direct and indirect methods based on the wireless modem of commercial cellular telephone. The former is a direct communication between the modems of the ship and the server. and the latter is an indirect communication via internet between the ship and the server. The system is equipped with a digital compass and a GPS system for position estimation, and extended Kalman filter is used for the data association. The performance of the ship is demonstrated with the results produced by sets of experiments.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.297-299
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• 2002

This paper is proposed maximum torque control for electric vehicle drive. At low speeds, the reluctance torque is used to maximize the output for a given current level. This Is achieved maximum torque per ampere(MTPA) by selecting an optimal value of the direct stator current component. At high speeds, the system reaches a point at which the inverter will not be able to supply the desired voltage In this case it Is necessary to make use of an increased value the direct current component. The proposed control algorithm is applied to PMSM drive system, the operating characteristics controlled by maximum torque control are examined in detail by simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.79-81
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• 2002

This paper develops a adaptive fuzzy controller based fuzzy logic control for high performance speed controller in permanent magnet synchronous motor(PMSM) drives. In the proposed system, fuzzy control is used to implement the direct controller as well as the adaptation mechanism. The operation of the direct fuzzy controller and the fuzzy logic based adaptation mechanism is studied. A model reference adaptive scheme is proposed in which the adaptation mechanism is executed by fuzzy logic based on the error and change of error measured between the motor speed and output of a reference model. The control performance of the adaptive fuzzy controller is evaluated by simulation for various operating conditions. The validity of the proposed adaptive fuzzy controller is confirmed by performance results for PMSM drive system.

• 한국정밀공학회지
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• 제21권3호
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• pp.59-65
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• 2004

The paper presents a small unmanned probing ship that can be used for acquiring information on marine and coastal environments. For communication system, we adopt direct and indirect methods based on the wireless modem of a commercial cellular telephone. The former is a direct communication between the modems of the ship and the server, and the latter is an indirect communication via internet between the ship and the server. The system is equipped with a digital compass and a GPS for position estimation, and extended Kalman filter is used for Navigation. The performance of the ship is demonstrated with the results produced by sets of experiments.

• 한국통신학회:학술대회논문집
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• 한국통신학회 2004년도 하계종합학술발표회논문초록집
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• pp.404-404
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• 2004

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 추계학술대회
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• pp.436-438
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• 2015

본 논문에서는 사물인터넷 게이트웨이 간의 직접통신 서비스를 제공하기 위해서 와이파이 다이렉트의 P2P Standard Group Formation(P2P-SGF)을 구현한다. 일반적으로 AP(Access Point)를 통해 사물인터넷 게이트웨이 간에 여러 센서들로부터 수집된 데이터와 더불어 대용량 데이터를 전송할 경우 네트워크 트래픽 혼잡 문제와 속도저하 문제가 발생한다. 이러한 문제를 해결하기 위해서 AP를 거치지 않고 사물인터넷 게이트웨이 간에 직접통신으로 대용량 데이터를 효율적으로 전송할 수 있는 와이파이 다이렉트 구현이 필요하다. 논문에서 구현한 P2P-SGF는 기본적으로 Discovery, GO(Group Owner) Negotiation, WPS(WiFi Protected Setup) Provisioning, Address Configuration을 수행하며, 특히 대용량 데이터를 공유하기 위해 DLNA(Digital Living Network Alliance) 서비스 기능을 지원한다. 구현한 P2P-SGF를 통해 대용량의 동영상이 성공적으로 공유되는 것을 실험실 테스트로 확인하였다.