• 기술사
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• 제31권1호
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• pp.9-16
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• 1998

For the flow facing high1y informationized age, there is a flow from fixed communications connecting fixed places such as offices and homes to mobile communications connecting mobile objets such as automobiles, ships and aircraft. This flow has added to diversifying communications Including data and images. While the axed mode is diversifying information media by digitalization of communications network and computers, the mobile mode has brought higher sophistication of communication modes by a higher degree of electric wave utilization. The following descriptions outlines the mobile communication which is utilizing the electric wave phenomena. In sequence the following items are described: a brief history of mobile communications, the technical object and various kinds of services, propagation of electric wave signal.

• 기술사
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• 제31권2호
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• pp.65-72
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• 1998

For the flow facing highly informationized age, there Is a flow from fixed communications connecting fixed places such as offices and homes to mobile communications connecting mobile objets such as automobiles, ships and aircraft. This flow has added to diversifying communications including data and images. While the fixed mode Is diversifying information media by digitalization of communications network and computers, the mobile mode has brought higher sophistication of communication modes by a higher degree of electric wave utilization. The following descriptions outlines the mobile communication which Is utilizing the electric wave phenomena. In sequence the following items are described: a brief history of mobile communications, the technical object and various kinds of services, propagation of electric wave signal.

• 기술경영경제학회:학술대회논문집
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• 기술경영경제학회 2002년도 제21회 하계학술발표회 논문집
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• pp.257-268
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• 2002

Korean mobile communications industry has been a main locomotive of the drastic development of Korean IT industry and became one of core industries in national economy. To secure strong competitiveness of mobile communications industry, smooth cooperation should be reconsidered among government, universities, research institutions, and private companies. Future mobile communications technology will be evolved from IMT-2000 to system upgrade, 3.5G and 4G. And the goals of technology development are provision of mobile multimedia services based on better mobility and higher data speed rates. Therefore, Korea's technology development strategies of mobile communications should be focused on intensifying bondage of international cooperation, strengthening standardization activities, and enhancing core technology development capability to secure IPR.

• ETRI Journal
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• 제37권6호
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• pp.1055-1064
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• 2015

We demonstrate a next-generation high-capacity mobile fronthaul based on radio over fiber (RoF) technology, which links between a digital unit and a radio unit supporting two frequency assignments and $2{\times}2$ multiple input, multiple output antennas. To confirm the technical feasibility of a mobile fronthaul, we experimentally investigate its down- and uplink end-to-end performances including the optical and radio frequency (RF) signal path. Frequency-dependent performance deviations, error vector magnitude variations, overall system performance variations caused by optical to electrical conversion, and intermediate frequency to RF conversions are examined. Experimental verifications on multiple LTE uplink signals are performed for the first time. We also demonstrate several commercial mobile Internet services, YouTube video streaming, and file transfers using off-the-shelf mobile devices, through a mobile fronthaul based on RoF.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권1호
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• pp.147-161
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• 2012

In recent years, machine-to-machine (M2M) communications are under rapid development to meet the fast-increasing requirements of multi-type wireless services and applications. In order to satisfy M2M communications requirements, heterogeneous networks convergence appears in many areas, i.e., mobile cellular networks (MCNs) and wireless sensor networks (WSNs) are evolving from heterogeneous to converged. In this paper, we introduce the system architecture and application requirement for converged MCN and WSN, where mobile terminals in MCN are acting as both sensor nodes and gateways for WSN. And then, we discuss the joint optimization of converged networks for M2M communications. Finally, we discuss the technical challenges in the converged process of MCN and WSN.

• 한국통신학회논문지
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• 제17권12호
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• pp.1371-1379
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• 1992

본 논문에서는 디지털 이동통신 시스템에 대하여 전반적으로 소개하고 가장 중요한 기능의 하나인 로우밍 기능 구현을 위한 클라이언트-서버 모델을 제안하고 이에 대한 실험 및 고찰에 대하여 기술한다.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.7-12
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• 2005

In this paper, we implemented an e-mail and chat program (client) for communication between mobile devices and PCs based on WIPI a South Korea's open wireless platform form developing device and content independent software to break from the way of developing contents that is dependent on different wireless platforms to each mobile communications company. While traditional e-mail and chat programs are written for PC-to-PC communication, we develop them for mobile-to-PC and mobile-to-mobile communications, and we expect to see various mobile contents in the future.

• 기술사
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• 제26권1호
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• pp.41-45
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• 1993

• Journal of information and communication convergence engineering
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• 제2권4호
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• pp.209-213
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• 2004

With the commercialization of CDMA 2000-1x late in 2000, a high-speed wireless Internet, based on a mobile communication networks, appeared in Korea. This will develop into the next-generation of mobile communications(4G) in the future and the new cell layout will be required the cellular configuration of 4G. We would need the legislation with respect to base-stations and to building the mobile communication networks, as well as the optimization of mobile communication systems. In this study, in order to provide 4G, I examined and analyzed that the current laws & regulations related to licensing and operating a mobile communication base-stations in KOREA.

• 한국멀티미디어학회논문지
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• 제6권3호
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• pp.518-526
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• 2003

이동통신의 발전에 따라 향후 이동통신 시스템은 많은 사용자들에게 고품질의 멀티미디어 서비스를 제공할 것이다. 따라서 이와 관련된 많은 기술적 응용 분야들이 고려되고 있으며, 특히 보안 관련 분야의 도입을 통해 기밀성 및 안전성을 획득하려 하고 있다. 본 논문에서는 이와 관련하여 이동통신 환경에서 상대적으로 계산능력이 뛰어난 에이전트(agent)의 도움을 통해 디지털 서명 및 암호화를 수행 할 수 있는 효율적인 Proxy-signcryption 방식을 제안한다. 제안방식은 대리서명을 수행할 경우 발생 할 수 있는 사용자와 대리서명 에이전트의 부정 서명 생성 및 부인행위를 방지하도록 구성하였으며, 동시에 정당한 수신자가 서명을 확인하도록 함으로서 이동 통신상에서 기밀성과 안전성을 유지하도록 하였다.