• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 연구회 합동 학술발표회 논문집
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• pp.60-63
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• 1998

The widely used power supply (Switched Mode Power Supply : SMPS) as a source in order to stabilize direct current for electronics or communication systems has merits, when it is compared to the existing source for stability, such as high efficiency, small size, light weight by means of switching process of the semiconductor device which controls the flow of power. However, due to existence of inductors and capacitors used for charging energy, the source part in electronic or communication systems hasn't reached the speed, that is supposed to get, for achieving smaller size and lighter weight. In order to get smallness in size, it is necessary to increase switching frequency. And that makes devices for measuring energy smaller. Nevertheless, the rise switching frequency brings increases in switching loss, inductor loss, and power loss. Also, the occurrence of surge and noise caused by high frequency switching is getting higher. The resonant converter has been considered as one of methods that give solutions for the problems of SMPS and that method have been paid attention as a source technology in electronics and communication.

• 한국통신학회논문지
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• 제16권7호
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• pp.651-662
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• 1991

공개키 암호화에 대한 지수계산 방법의 개선과 serial 통신선에 실용적으로 적용하는 방법을 제시한다. RSA 형의 암호화 및 복호화 회로에 사용하기 위한 고속 modular 곱셈 알고리즘을 개선하였다. 기존의 고석 modular 곱셈 알고리즘에서 비교 과정에 사용되는 control bit 값 선정을 개선하여 부분곱과 modular 값의 비교과정에서 오류가 발생되지 않도록 하였다. 이 개선된 알고리즘은 C언어를 사용하여 작성한 simulation program에 의한 simulation을 통하여 그 정상 동작을 확인하였다. 또한 computer간의 serial 통신선에서 입력되는 serial 통신선에서 입력되는 serial data를 sampling하여 이것을 RSA방식으로 암호화하여 송신하게 되고 수신측에서는 이의 역순으로 처리하며, 이 sampling 및 암호화에 Z80 miroprocessor를 중심으로 암호회로를 설계, 제작하였다.

• 제어로봇시스템학회논문지
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• 제9권12호
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• pp.1055-1064
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• 2003

In many automated systems, such as manufacturing systems and process plants, a fieldbus is a very important component for the exchange of various and sometimes crucial information. Some of the information has a tendency to rapidly lose its value as time elapses after its creation. Such information or data is called real-time data that includes sensor values and control commands. In order to deliver these data in time, the fieldbus network should be tailored to have short delay with respect to the individual time limit of various data. Fine-tuning the network for a given traffic requires the knowledge on the relationship between the protocol parameters such as timer values and the performance measure such as network delay. This paper presents a mathematical performance model to calculate communication delays of the Profibus-FMS network when the timer value and the traffic characteristics are given.

• 대한가정학회지
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• 제42권5호
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• pp.11-25
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• 2004

This study analyzed information sharing and digital divide within family and their consequences on the power structure between parents and their children based on the resource-exchange theory. In-depth interview has been conducted to collect data and materials for analysis. Major findings are: first, children recognized the ability to use information technology as resources, while parents did not; second, digital divide between parents and children seemed to be associated with laissez-faire communication between parents and children and worked as a cause of conflict between parents and children; third, reverse-socialization from children to parents occurred in consumer socialization in the family. Based on the findings, the implications to further research were provided.

• Journal of Advanced Marine Engineering and Technology
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• 제34권8호
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• pp.1145-1152
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• 2010

현재 해상통신망에는 고속의 데이터 송수신을 위한 경제적인 통신기술이 요구되고 있다. 해상에서는 무선통신에 전적으로 의존할 수밖에 없는 환경으로 인해 취약한 데이터 통신보안에 대한 해결책도 함께 제시되어야 한다. 이 논문에서는 광대역 해상통신망의 위와 같은 현안들을 해결하기 위하여 다중 홉 자율통신망 형성기술 가운데 하나인 WiMAX MMR 기술을 도입하고, 육상과 달리 기지국이 없는 해상 상황에서 안전한 자율망을 형성하기 위해 확장된 프로토콜을 제안한다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 춘계종합학술대회
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• pp.556-559
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• 2001

미국은 국가통신망 안전 보장을 위해 합의된 표준을 가져야 할 필요성이 대두되어 정부 및 산업계에 동 분야의 연구를 수행하도록 적극 권장하고 있다. 미국연방통신위원회(FCC)는 교환기사업자표준협회를 통해 전기통신표준에 대한 민간차원의 표준화 기구를 미국내에 설립한 것을 검토하여 1985넌 미국 T1위원회가 6개 실무작업반과 27개 기술위원회로 구성되어 설립되었다. 본 고에서는 미국 표준화를 이끌어가고 있는 T1위원회의 각 연구반별 연구활동에 대하여 논의하고자 한다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.941-943
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• 2013

스마트미터가 전력공급자와의 양방향 통신을 통하여 요금정보와 전기사용 상황을 서로 주고받기 위해서는 표준화된 통신 프로토콜이 필요하게 된다. 이 통신 프로토콜은 사용자의 인증과 보안을 해결하고 사용자측에서 소비되는 전기 사용량을 전기 공급자에게 전달하게 된다. 본 논문에서는 스마트미터의 국제통신 프로토콜이 적용된 양방향 통신 및 제어 기술, 전기 기기의 등록 및 해제를 위한 통신방식을 설계하였다.

• Journal of Electrical Engineering and Technology
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• 제5권4호
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• pp.561-570
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• 2010

This paper presents an advanced dynamic simulation model of a proton exchange membrane fuel cell for the optimal design of a fuel cell power conditioning system (FC-PCS). For the development of fuel cell models, the dynamic characteristics of the fuel cell are considered, including its static characteristics. Then, software fuel cell simulation is realized using Matlab-Simulink. Specifically, the design consideration of PCS (i.e., power semiconductor switch, capacitor, and inductor) is discussed by comparatively analyzing the developed simulator and ideal DC source. In addition, a cosimulation between the fuel cell model and PCS realized using the PSIM software is performed with the help of the SimCoupler module. Detailed analysis and informative simulation results are provided for the optimal design of fuel cell PCS.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.293-293
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• 2000

The SECS(SEMI Equipment Communications Standard) is a standard protocol for communication between equipments and a host in semiconductor processes. This paper proposes the implementation of the HSMS(High-speed SECS Message Services) as an interface for transmission of the SECS messages and SECS-II containing message contents defined as an SEMI standard. The HSMS driver is implemented as a type of the daemon program and several DLL files. The SECS-II composes of the SML(SECS Message Language) file defining the SECS messages, the SML translator being able to interpret and transform the SML, and the data index table being able to refer to SECS messages. We also define the shared parameter to exchange the HSMS header and SECS message between the HSMS and the SECS-II. Eventually, to show the effectiveness of the proposed drivers, we test the SECS communications between equipments and a host using the implemented communication programs.

• Journal of Communications and Networks
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• 제14권1호
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• pp.63-74
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• 2012

Multicast data communication is an efficient communication scheme, especially inmulti-hop ad hoc networks where the media access control (MAC) layer is based on one-hop broadcast from one source to multiple receivers. Compared to unicast, multicast over a wireless channel should be able to deal with varying channel conditions of multiple users and user mobility to provide good quality to all users. IEEE 802.11 does not support reliable multicast owing to its inability to exchange request-to-send/clear-to-send and acknowledgement packets with multiple recipients. Thus, several MAC layer protocols have been proposed to provide reliable multicast. However, additional overhead is introduced, as a result, which degrades the system performance. In this paper, we propose an efficient wireless multicast MAC protocol with small control overhead required for reliable multicast in multi-hop wireless ad hoc networks. We present analytical formulations of the system throughput and delay associated with the overhead.