• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.150-152
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• 2011

최근 들어 일본의 대지진과 같이 "위험사회"에서 발생할 수 있는 여러 현상들이 나타나고 있다. 국가는 위험한 상황을 신속하게 국민에게 전달하여 국민의 생명과 재산을 보호해야하는 중요한 의무를 가진다. 이러한 국가의 의무를 효과적으로 수행하기 위해 국가는 법령에 재난정보전달에 필요한 사항을 규정한다. 본 고에서는 우리나라의 법령 중 재난정보전달과 관련된 법령을 수집하여 분석한다. 이를 위해 헌법, 자연재해대책법, 재난 및 안전관리 기본법, 방송통신발전기본법, 기상법, 마지막으로 민방위기본법과 관련 시행령을 조사하였다. 결론으로 이러한 법령과 관련 조직이 현재 가지고 있는 문제점을 파악하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.310-313
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• 2011

Broadcasting nature of wireless communications makes it possible to apply opportunistic network coding (OPNC) by overhearing transmitted packets from a source to sink nodes. However, it is difficult to apply network coding to the topology of multiple relay and sink nodes. We propose to use relay node selection, which finds a proper node for network coding since the OPNC alone in the topology of multiple relays and sink nodes cannot guarantee network coding gain. The proposed system is a novel combination of wireless network coding and relay selection, which is a key contribution of this paper. In this paper, with the consideration of channel state and potential network coding gain, we propose relay node selection techniques, and show performance gain over the conventional OPNC and a channel-based selection algorithm in terms of average system throughput.

• Journal of Korea Multimedia Society
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• v.8 no.6
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• pp.814-826
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• 2005

The user-centric broadcasting environment includes the agent system and personalized broadcasting services for user-adaptive TV watching. In this paper, we propose broadcasting environment consisting of personalized broadcasting services and a multi-agent broadcasting system for the services. The proposed system employs the intelligent agent technology of the Foundation for Intelligent Physical Agents (FIPA) as well as metadata technology of MPEG-7 and TV-Anytime Forum (TVAF). To verify the usefulness of the proposed environment, we implemented a test-bed and demonstrated the proposed agent system with three services including intelligent user-information management service, information mobility service, and content retrieval service.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.8
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• pp.1176-1189
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• 1993

This paper presents the Multiple Keyword Retrieval Method under the Object-Oriented Multimedia Database Model. The multiple keyword registration and retrieval algorithms are developed to reduce the partial matching problem in multimedia data retrieval. For this, proper storage structures of the lookup tables are designed. And also, in order to maintain the constant retrieval time, media data files are organized with B+ tree structure.

• Information and Communications Magazine
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• v.18 no.10
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• pp.88-98
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• 2001

iMS(Interactive Media Solution) 또는 대화형 미디어 솔루션 프로젝트에서는 대화형, 맞춤형, TVN 서비스를 제공하기 위한 엔드-투-엔드 솔루션을 개발한다. iMS 프로젝트가 개발대상으로 삼는 대화형 서비스는 시청자의 방송참여를 제한적이지만 부분적으로 허용하는 것을 목표로 삼고 있다. 일반적으로 대화형 서비스는 데이터방송을 통해 부가정보를 제공하는 것으로 한정하지만 iMS 프로젝트에서는 그 범위를 더 넓혀 T-커머스를 킬러 애플리케이션으로 삼는다. 데이터표현 규격은 ATSC-DASE(Dase-1) 및 DVB-MHP(버전 1.0) 규격을 기반으로 삼는다. 맞춤형은 시청자가 원하는 서비스를 신속하고 편안하게 받을 수 있도록 지원하는 것을 목표로 삼고 있다. 맞춤형은 마땅한 참조모델이 없지만 TV Anytime 규격을 원용할 예정이다. TVN은 방송과 홈 네트워크를 결합하기 위한 새로운 개념을 말한다. 이 기고문은 이들 서비스의 개념과 목표 및 구현방법 등을 소개한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.4B
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• pp.391-399
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• 2001

In this paper, electromagnetic wave scattering from a bianisotropicaly coated cylinder is formulated by using wave functions for bianisotropic media and boundary-value method. The cross section of the cylinder is made of a conducting core, a lossless dielectric layer which is both electrically magnetically bianisotropic, and a bianisotropic impedance sheet and a different uniaxial bianisotrpic coating. The solutions to arbitrary polarization angles are presented in two-dimensional. This paper presents and exact solution to the problem of scattering by a long composite circular cylinder using the boundary method. The validity of this solution is verified by comparing numerical results with those in literature. The numerical results for various geometrical and electrical parameters on bistatic scattering cross-section are presented.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.467-469
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• 2006

In wireless network environments, as users' demands on high-speed data communications due to increase of multi-media services, the necessity of new high-speed WLAN technologies has appeared. Nowaday, IEEE is standardizing a new WLAN protocol caned as IEEE 802.11n. To effectively use wireless resources, IEEE 802.11n introduces MAC aggregation function which is similar to that in IEEE 802.11e. In case of transmitting several frames without MAC aggregation, the frames include individual frame header and trailer, and their corresponding acknowledgement frames can appear on wireless link. However, if they are aggregated into single MAC frame, we can reduce the number of used bits due to frame headers/trailers and also remove redundant acknowledgement frames. In this paper, we explain two different MAC frame aggregation methods for IEEE 802.11e and IEEE 802.11n and evaluate their throughput by simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.6A
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• pp.474-480
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• 2005

In this paper, we present a new scheduling scheme for MIMO OFDM Multiuser Diversity System. This scheduling scheme maximizes the system throughput, and at the same time fairly shares the resources based on the feedback information from the receivers and the queue information. To show the effectiveness of the proposed algorithm, we evaluate the performance of the proposed algorithm as compared to K&H and RR algorithms.

• Journal of Communications and Networks
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• v.7 no.3
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• pp.235-242
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• 2005

Multimedia applications and especially encoded video services, are expected to playa major role in the 3rd generation (3G) and beyond mobile communication systems. Given that future service providers are expected to provide video applications at various price and quality levels, quick and economically affordable methods for preparing/encoding the offering media at various qualities are necessary to be developed. This paper presents a method for objective evaluation of the perceived quality of MPEG­4 video content, based on a quantification of subjective assessments. Showing that subjectively derived perceived quality of service (PQoS) vs. bit rate curves can be successfully approximated by a group of exponential functions, the proposed method exploits a simple objective metric, which is obtained from the mean frame rate vs. bit rate curves of an encoded clip. The validity of this metric is assessed by comparing subjectively derived PQoS results to the corresponding ones, which come from the proposed objective method, showing that the proposed technique provides satisfactory PQoS estimation.

• Electronics and Telecommunications Trends
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• v.4 no.1
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• pp.35-43
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• 1989

The evolution of telecommunications has raised the profile of many segments of the network that were not previously considered important. Until recently, basic telephony existed with the extension of passive cables without any particular user network interface. In the area of data communications, the introduction of flexible packet switching has allowed the network to evolve in a far more efficient manner. To overcome such separated network problems and business needs of both users and network providers, the integrated narrowband ISDN concept is being developed in most countries for implementation in the public switched telephone network (PSTN). The targets of ISDN, in my opinion, can be explained as follows : To the user, ISDN should provide the services at any time, at any place, through any media. To the business customer using PABX or LAN applications, ISDN should introduce customized services rapidly and also, ISDN should be developed by the modular hardware and software design approach in order for new services to be introduced rapidly and effectively. Software can be also developed by non-expert local staff to cater for adopting new user's service requirements immediately. Finally, ISDN will be able to increase business chances and benefit both users and operating companies.