• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.1028-1031
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• 1997

This Paper Presents a new digital balance relaying technique in two Parallel transmission lines. To obtain relaying signals, selected model is simulated using EMTDC. Test results of the proposed method show efficacy.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 통신소사이어티 추계학술대회논문집
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• pp.382-385
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• 2003

Introduction of digital broadcasting service does not only mean the change of information transmission method but also the change of total broadcasting system. In past day, Television was only received one-sided information from broadcasting station, but digital broadcasting means that digital television becomes the most important means of information transmission by the introduction of new programming, lots of channels, data service, multi communication. In the age of the digital broadcasting, the recording and replay medium's interest is getting higher. The medium is able to record more than 24 hours' digital broadcasting programs without additional tapes. In this paper the recording and replay device using HDD was implemented and device driver based on linux was programmed. It has Intel PXA250 processor and hard disk is used as storage equipment. And transport Stream is saved on hard disk through PXA250's data bus. FIFO is added to solve the different saving speed and FPGA is also added to display the saved data.

• 전기의세계
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• 제28권10호
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• pp.41-47
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• 1979

The paper develops a method of minimizing power transmission losses by optimum control of reactive power flow. In the past, because the optimizing method considers as the first step the minimization of node voltage deviations and as the second step the minimization of transmission losses within the system, the calculating procedure was more complex and difficult to handle. In this paper, a new computing method for real time control on a digital computer is described which aims at a coordinated use of reactive power sources and voltage regulating devices. The power transmission losses are minimized by a gradient method while satisfying the constrained system voltage conditions and sensitivity parameters are the basis of the method.

• 조명전기설비학회논문지
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• 제29권9호
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• pp.23-32
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• 2015

In order to complete engineering works of the digital substation, Both Data transmission among a variety of IEDs and HMIs, and single line diagram of the substation might be done based on XML documents published in IEC 61850 international standards. This kind of XML based engineering process for the digital substation must be implemented not by manual written work but by the engineering tool using a computer. But most of the engineering tools do not support system based engineering works such as single line diagram of the substation but have only function to set IEDs as single device unit. Accordingly, this paper presents a new design method of the system based engineering description applicable to real IEC 61850 based substation through analyzing the current international standard and its sampled engineering file, and shows implementation of the engineering tool of the digital substation with the result of this study.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.440-442
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• 2000

This paper describes the digital distance algorithm in case of combined transmission line connected with overhead line and underground cable. Actually as fault is occurred in cable, it results in the complicated phenomena due to the several kind of grounding method in the sheath of cable. Accordingly the impedance. Therefore the correct impedance calculation algorithm is requested in combined transmission line to avoid the wrong trip of relay. This paper presents the development result of impedance calculation algorithm In such transmission line.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.2055-2058
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• 2002

It designs the general description of 8-VSB DTV transmission system will be installed and operated in future on the basis of NTSC TV transmission system in operation now. First of all, it investigates a condition that can maintain optimum received field in case of ground wave broadcasting with analog NTSC and digital 8-VSB DTV. Also it calculates critical value of minimum field strength fur receiving by using field strength calculation method of Longley-Rice. The 8-VSB DTV transmission sets its goal in transmission of data with 19.39Mbps at high speed in order to be available of HDTV in the band of NTSC 6MHz. Accordingly, the optimum of field strength between transmission and receiving points most of all is important problem. So,8-VSB DTV transmission should be enlarged or effective compared with NTSC service coverage. This study is to calculate the transmission power necessary in switching from NTSC VHF to DTV UHF and from NTSC UHF to DTV UHF for maintaining service coverage that NTSC is equal to 8-VSB DTV as a result of calculation.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.175-178
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• 2003

This paper proposes a stereo image insertion technique on DCT coefficients using the embedded method developed in the digital watermarking in due consideration of compatibility with conventional 2D system such JPEG, and MPEG. In conventional transmission method users with conventional digital TV cannot watch the transmitted 3D image sequence as 2D image, because of affectivity of conventional 3D image compression. To give an answer, in this paper, DCT coefficients are changed according to its disparity on YCbCr channels. Our method can insert stereo images into a conventional image compression method based on DCT.

• 대한전자공학회논문지
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• 제21권2호
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• pp.24-28
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• 1984

이선 선로를 통한 full-duplex 데이타 전송에 있어서 hybrid-coupler의 불완전한 송·수신에 따른 반향신호는 데이타 검출에 큰 장애가 되고 있다. 본 논문에서는 산술평균에 의한 반향신호 추정법을 제시하고 이를 적응 디지탈 필터에 의한 추정법과 이론적 해석 및 컴퓨터 시뮬레이션을 통해 비교하였다. 양자화 효과를 고려한 이론적인 해석 결과 산술평균 추정을 사용한 반향제거는 hardware 구성이 간단하면서도 수렴이 매우 빠름을 밝혔다. 특히 제시된 방식은 선로 감쇠량에 관계없이 반향신호를 정해진 시간내에 충분히 제거할 수 있다.

• 디지털산업정보학회논문지
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• 제12권3호
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• pp.75-85
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• 2016

MANET is a network composed only mobile network having limited resources and has dynamic topology characteristics. Therefore, every mobile node acts as a route and delivers data by using multi-hop method. In particular, group communication such as multicast is desperately needed because of characteristics such as battery life of limited wireless bandwidth and mobile nodes. However, the multicast technique can have different efficient of data transmission according to configuring method of a virtual topology by the movement of the nodes and the performance of a multicast can be significantly degraded. In this paper, the region based security multicast technique is proposed in order to increase the efficiency of data transmission by maintaining an optimal path and enhance the security features in data transmission. The group management node that manages the state information of the member nodes after the whole network is separated to area for efficient management of multicast member nodes is used. Member node encrypts using member key for secure data transmission and the security features are strengthened by sending the data after encrypted using group key in group management node. The superiority of the proposed technique in this paper was confirmed through experiments.

• 한국정보통신학회논문지
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• 제3권2호
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• pp.255-265
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• 1999

최근 정보통신 기술의 발달로 통신 시스템의 디지털화, 고속화, 소형 경량화 요구에 따라 통신기기 회로의 설계는 수동소자와 능동소자의 복합 형태를 나타내고 있으며, 정보 통신 기기에서 디지털 신호의 전송속도가 높아짐에 따라 선로의 종류와 특성에 따라 발생하는 누화(Crosstalk)와 상호 결합 등의 문제로 인하여 데이터의 손실 및 왜곡이 발생한다. 이런 문제점을 해석하기 위해서는 전송 선로를 등가적인 회로로 표현하는 것이 필요하며 중요하다. 본 논문에서는 전송 선로의 등가 파라미터를 계산하기 위해 모멘트법을 이용하여 단층 및 다층 구조의 마이크로 스트립 선로에 대한 해석 결과를 비교하여 나타낸다.