• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.587-590
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• 2013

스마트 그리드는 기존의 전력망과 함께 양방향 통신을 위한 정보통신기술이 접목된 형태로, 전기의 생산, 운반, 소비뿐만 아니라 사용량 확인, 상호작용 등의 과정을 효율적으로 제공한다. 이와 같은 환경에서 전송되는 정보는 개인의 소비 성향과 같은 민감한 정보를 포함하고 있으므로, 안전한 통신을 위한 암호화가 필수적으로 요구된다. 특히, 다수의 장치가 계층적 구조를 이루는 스마트 그리드 환경에서는 암호화를 위하여 효율적인 그룹 키 사용이 필수적으로 요구된다. 따라서 본 논문에서는 스마트그리드 환경에서 효율적인 그룹 키 분배를 위하여 그룹 키 원소 배열에서 일정 범위를 한정하는 윈도우를 이용한 기법을 제안한다.

• Korean journal of communication and information
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• v.27
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• pp.213-245
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• 2004

As we know, broadcasting implies a unilateral transmission by one sender to several recipients of information generally produced by third parties. Contrary to that, telecommunications implies an exchange between participants. Participants exchange information they produce during an interaction. However, in the age of convergence between telecommunication and broadcasting, it becomes difficult to determine exactly the boundary between services classified under telecommunications and those classified under broadcasting services. This means that new regulatory regime should be introduced to meet the convergence between telecommunication and broadcasting. In this article, we try to overcome the existing framework for understanding and regulating convergent services. In order to develop more powerful and useful framework for dealing with new convergent services, we focus on the original characteristic of "cast services," which could give us very significant basis for further discussion. "Cast services," such as traditional broadcasting services, have the characteristics of both public goods (non-exclusivity and non-rivalry in consumption) and non-interactivity. Depending on the existence of these three characteristics, we are able to apply different regulatory regime to those convergent services.

• Journal of Broadcast Engineering
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• v.21 no.1
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• pp.109-112
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• 2016

This paper analyzes the outage performance of a two-way relay network in the presence of interference from multiple interferers. We investigate a two-way relay network where a single user communicates with a selected other user via a relay during three phases. We propose a user selection scheme and analyze an outage probability. Numerical results verify our analysis by comparison with computer simulation and show effects of the number of users and the number of interferers on its the outage probability.

• Electronics and Telecommunications Trends
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• v.23 no.3
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• pp.119-129
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• 2008

개인 휴대형 이동위성통신/방송 기술은 2GHz대의 L 대역이나 S 대역의 주파수를 이용하여 이동하는 사용자에게 소형의 휴대형 단말기를 통하여 양방향의 통신 및 방송 서비스를 제공하는 기술이다. 본 고에서는 우선 현재까지의 개인 휴대형 이동위성통신/방송 기술의 발전에 대해서 살펴본 후, 국내외 기술개발 동향을 소개한다. 마지막으로 국내에서 연구가 진행중인 IMT-Advanced 위성접속기술에 대한 소개로 향후 개인 휴대형 이동위성통신/방송 기술의 발전 방향에 대해 전망해 보고자 한다.

• Information and Communications Magazine
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• v.26 no.6
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• pp.3-10
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• 2009

개인 휴대 위성통신/방송 기술은 L대역이나 S대역의 주파수를 이용하여 이동하는 사용자에게 소형의 휴대형 단말기를 통하여 양방향의 통신 및 방송 서비스를 제공하는 기술이다. 본 고에서는 우선 현재까지의 개인 휴대 위성 통신/방송 기술의 발전에 대해서 살펴 본 후, 국내외 기술 개발 동향을 소개한다. 마지막으로 국내에서 진행중인 연구에 대한 소개 및 향후 개인 휴대 위성 통신/방송 기술의 발전 방향에 대해 전망해 보고자 한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.7
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• pp.118-126
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• 2003

In this study, a battery charge and discharge regulator of modular type is designed as paralleled bi-directional converter that is possible to provide the power without failure not only in the steady state but also in the transient period by the step load variation or the unexpected faults among the converter modules. Each converter module is designed to get stability, performance, reliability, and maintainability and the average current mode method used for controller has the advantages such as noise immunity, fast response, and the real average current signal acquisition. The equivalent model and small signal model for the paralleled battery chargerIdischarger are presented, and also the transfer functions are analyzed for the CCM(Continuous Charge Mode), CDM(Continuous Discharge Mode) and DDM(Discontinuous Discharge Mode). The experiments of the paralleled bi-directional converter are carried out in the step load variation, and in faults of one converter module respectively. And the performance of paralleled bi-directional converter is verified via the experimental results.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.3
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• pp.155-164
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• 2009

Digital Content Marketplace based on Interactive Media is defmed as the marketplace for content service between contents supplier and consumer through iDTV environment. This Marketplace is increasing interest to u-Life service with Digital Environment. To Interactive Media, it can contribute to enhance its effectiveness by developing various contents and service model in the initial phase of broadcasting-communication convergence. This study designed metadata using Digital Content marketplace based on Interactive Media. Specially the matadata designing include recommendation-tag for supply supplementary content. It can support self-directed action. Through basic metadata with weight value, it is designed to support supplementary content customer to want on the marketplace. Recommendation-System can be built by many method and to recommend the service content including explicit properties using collaborative filtering method can solve limitations in existing content recommendation.

• Information and Communications Magazine
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• v.30 no.12
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• pp.76-82
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• 2013

본 고에서는 전력시스템의 효율화를 위한 스마트그리드(Smart-grid) 통신 기술을 소개하고, 스마트그리드 통신의 다양한 문제를 해결하는데 사용될 수 있는 게임이론(Game theory)의 응용에 대해서 살펴보도록 한다. 스마트그리드는 에너지 ICT융합기술로써 전력의 수요와 공급에 대한 정보가 실시간으로 양방향 통신이 가능하기에 기존의 단방향 전력 시스템과 비교해서 에너지 효율적이고 안정적이라는 장점이 있다. 전통적인 전력시스템과는 달리 스마트그리드 환경에서는 다수의 분산전원 공급자가 존재할 수 있으며, 전력의 소비자 또한 전력시장에 영향력을 행사할 수 있는 메커니즘을 가지고 있다. 그에 따라 복수의 공급자와 소비자로 이루어진 합리적인 경제주체들이 어떤 의사결정을 하는가에 대하여 게임이론을 통해 분석하는 연구가 활발하다. 본 논문에서는 특별히 스마트그리드에서 중요한 역할을 담당할 것으로 예상되는 수요관리(DSM: Demand Side Management)및 마이크로그리드(Micro-grid)를 소개하고 게임이론과 접목시킨 연구들을 살펴보기로 한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.3
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• pp.47-53
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• 2013

In this paper, we propose an incremental cooperative transmission protocol in two-way underlay cognitive radio networks. In the proposed protocol, two secondary sources attempt to transmit their packet to each other with help of a secondary relay under interference constraint. For performance evaluation, we derive exact closed-form expressions of average outage probability over Rayleigh fading channel. Then, we perform Monte Carlo simulations to verify the derivations. Results present that the simulation and theoretical results are in good agreement and the outage performance of the proposed protocol is better than that of two-way direct transmission protocol.

• Journal of Satellite, Information and Communications
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• v.10 no.2
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• pp.102-108
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• 2015

In general, two way satellite communication systems based on TDMA(Time Division Multiple Access) require network clock synchronization between hub station and remote terminals. This paper describes basic concepts for network clock synchronization based on NCR(Network Clock Reference) clock recovery scheme as suggested in DVB-S2/ RCS2 international standards. in addition, a new NCR insertion method has been proposed and evaluated in terms of supporting CCM mode as well as ACM mode which optimizes throughput by changing code rates and modulation types ranging from QPSK to 32-APSK.