• Proceedings of the Korean Information Science Society Conference
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• 2008.06d
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• pp.285-290
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• 2008

이동통신 서비스를 이용해 인터넷의 콘텐츠를 다운로드 받으면 통신비용이 자료의 양에 비례하여 사용자에게 부과된다. 각 Peer가 콘텐츠의 일부를 3G 채널 등을 이용하여 유료로 다운로드 받고 비용이 부과되지 않는 ad hoc 채널에서 콘텐츠의 나머지 부분을 다른 Peer와 교환하여 전체 콘텐츠를 구성하면 사용자에게 부과되는 비용을 절감할 수 있다. 본 논문은 각 사용자가 가지고 있는 일부의 콘텐츠를 교환하여 전체 콘텐츠를 구성하는 방법인 benefit value를 설명하고, benefit value 값이 변경되지 않아 전송횟수가 증가하는 현상을 benefit bitmap으로 해결할 수 있는 방법을 제안한다. 시뮬레이션 결과에 따르면 1Mbyte 파일을 5개의 Peer가 나누어 다운로드 받아 패킷을 512 byte와 1024 byte 크기로 교환했을 때, benefit bitmap을 사용하면 benefit value와 비교해 패킷 송신을 위한 버퍼의 크기가 100인 경우 약 22%, 버퍼가 3000인 경우 약 10% 정도 전송시간을 단축할 수 있다.

• 전기의세계
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• v.39 no.5
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• pp.27-37
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• 1990

In this paper some of the important trends in the spacecraft technology development have been discussed. Trends of higher satellite radiate power, which involves higher TWTA powers and antenna reconfiguration, and Ka-band (30/20 G $H_{z}$) utilization are discussed. Evolutionary trends in satellite communications in general have demonstrated immense potential for meeting the evolving nees and challenges regarding provision of global telecommunications during over past two decades. Their promise for the coming decades as we enter the 21st century may far surpass our imagination. The expansion of fixed satellite service market will depend upon more inelligent spacecraft and a network of more cost effective small earth stations. Radiation hardened microwave analog technologies and high speed digital technologies are getting ready to meet the challenge posed by future markets. At present commercial satellite communications are going through a trasition period.d.

• ETRI Journal
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• v.39 no.2
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• pp.255-263
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• 2017

This paper proposes a graph-theatrical approach to optimize spatial reuse by adopting a technique that quantizes the channel information into single bit sub-messages. First, we introduce an interference graph to model the network topology. Based on the interference graph, the computational requirements of the algorithm that computes the optimal spatial reuse factor of each user are reduced to quasilinear time complexity, ideal for practical implementation. We perform a resource allocation procedure that can maximize the efficiency of spatial reuse. The proposed spatial reuse scheme provides advantages in beamforming systems, where in the interference with neighbor nodes can be mitigated by using directional beams. Based on results of system level measurements performed to illustrate the physical interference from practical millimeter wave wireless links, we conclude that the potential of the proposed algorithm is both feasible and promising.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.208-215
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• 2001

The vertical irregularities occurred in the structure may lessen the overall seismic capacity of the structure. Seismic capacity evaluation guidelines (e.g. FEMA 175, ATC-14) propose the criterion for the vertical irregularities of mass, stiffness and strength respectively. But, the criterion seems groundless and leads us to make a true/false decision only. This study is to draw a reasonable basis on which multi-level grading is possible based fur the evaluation of existing buildings. Time history analysis for 3-,5-, and 10-story steel frame structures has been performed using several earthquake data. ANN (Artificial Neural Network) is introduced to find the relative contribution factor of the irregularities along the irregular position. Also, the application system fur the seismic capacity evaluation can be established using the trained ANN.

• Electronics and Telecommunications Trends
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• v.13 no.5 s.53
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• pp.23-37
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• 1998

ATM over Legacy LAN 기술은 기존의 근거리 통신망(local area network: LAN) 환경하에서 하드웨어의 교체 없이 ATM 셀을 수용할 수 있도록 하여 음성과 데이터를 제공하는 효과적인 기술로서, 순수 ATM 통신망으로 진화하는 과도기적인 시기에 아주 유용한 기술로 여겨지고 있다. 지금까지 연구된 ATM over Legacy LAN 기술은 ATM Forum의 FUNI 프로토콜, Cornell 대학의 CIF, 그리고 Melbourne 대학의 gNET 프로토콜의 세가지가 있으며, 이들 기술은 ATM 프로토콜의 ATM 적응 계층 기능을 LAN 단말과 LAN 스위치에서 각각 어느 범위까지 담당하는가에 따라 구분되는 기술이다. 본 고에서는 이들 세가지 ATM over Legacy LAN 기술에 대해 그 구조 및 기능을 살펴보고 지금까지의 연구 동향을 토대로 하여 각 기술의 장단점을 살펴보고자 한다.

• Journal of the Korean Society for Railway
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• v.9 no.5 s.36
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• pp.612-617
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• 2006

As the on-board electric devices determine the performances of vehicles, production of reliable devices is important. To keep the reliability of devices constant, management of performance evaluation of the on-board devices is crucial. Because temperature has a serious effect on failures of the components of the devices, its measurement is the first step for good management. In this study, we described performance characteristics of domestic auxiliary block developed through G7 project. We measured the performances of auxiliary block during test running by the developed on-line measurement system. After we save the input real-time data from each signal of Korean High Speed Train through the network line, we can acquire necessary information through post-processing program. We verify the motor block characteristics of Korean High Speed Train by this system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.1
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• pp.49-54
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• 2004

This paper is purpose to manufacture of inhibitor switch using CAM systems. CAM systems are consist of CAD(AutoCAD), CAM(Omega) software and CNC milling machine. CAM software is purpose to G-code generation for CNC programming. Then CAM software and CNC milling machine are connect to RS-232-C cable for data network.

• Korean Journal of English Language and Linguistics
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• v.2 no.1
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• pp.123-147
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• 2002

As far as the recent ELT research concerned, it seems to have been no hot ‘theoretical’ issues, but ‘practical’ ones in general: e.g., learners and learning, components of proficiency, correlates of L2 learning, etc. This paper focuses on the theme given above, with a special reference to the sub-title: specifically, 1) World English, world Englishes and world's lingua franca; 2) ENL, ESL and EFL; 3) Grammars, style manuals, dictionaries and media; 4) Pronunciation models: RP, BBC model and General American, Network Standard; 5) Lexical, grammatical variations and discourse grammars; 6) Beliefs and subjective theories in foreign language research; 7) Dilemma among radical, canonical and eclectic views. In conclusion, the author offers a modest proposal: we need to appeal to our own experience, intention, feeling and purpose, that is, our identity to express “our own selves” in our contexts toward the world anywhere, if not sounding authentic enough, but producing it plausibly well. It is time for us (with our ethno-cultural autonomy) to need to be complementary to and parallel with its native speakers' linguistic-cultural authenticity in terms of the broadest mutual understanding.

• Information and Communications Magazine
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• v.19 no.5
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• pp.63-78
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• 2002

IEEE1394 기술은 오디오 비디오 기기의 디지털화가 이루어지고 멀티미디어 환경이 부상함에 따라 이들간의 공통된 새로운 인터페이스 방식의 필요에 의해 발생한 직렬 버스 방식을 이용한 디지털 인터페이스 방식으로, 고속의 실시간 데이터 전송을 가능하게 해 주는 차세대 핵심 기술이다. 기가비트급의 높은 데이터 전송율을 자랑하는 IEEE1394 기술은 따라서 멀티미디어 PC와 오디오/비디오 등 높은 대역폭을 요구하는 가전기기를 하나로 묶어줄 수 있는 유일한 기술이며, 그 위에 TCP/IP 프로토콜을 얹어서 인터넷과도 직접 연결되므로, 옥내 통신망 구축을 위하여 제안되고 있는 HomeRF나 Bluetooth, 그리고 IEEE 802.11 계열의 기술들과 비교하면 그 효용성과 기능성, 그리고 필요성과 속도 면에서 다른 위치를 점유하고 있다. 따라서 IEEE1394 기술은1394b와 같은 유선 흠 네트워킹 기술을 사용하거나 IEEE802.1la 혹은 11g와 같은 무선 랜 기술을 이용한 Home Network의 Backbone 기술을 이용하면 IEEE1394 기술이 갖고 있는 미래의 시장 규모는 가히 폭발적이라 할 수 있다.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1900-1902
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• 1997

In order to obtain various waveforms of current pulse applied at the flashlamp, we have fabricated a Pulsed Nd:YAG laser by PFN with multiple-mesh formed LC network. we have obtained various waveforms of current pulse by adjusting the values of L and C, compared these waveforms of current pulse with laser beam, and then analyzed the laser output energy. We have got relations for $E_{TH}$ and $E_L$ at each mesh which supplies energy with flashlamp and found that output of Pulsed Nd:YAG Laser for 2-mesh, 5-mesh coincided with computer's simulation, PSPICE.