• Proceedings of the Korea Multimedia Society Conference
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• 1998.10a
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• pp.68-76
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• 1998

본 논문에서는 의료 정보 보호를 위한 위협요소를 제시한다. 의료 정보 시스템은 무결성, 기밀성을 기반으로 하는 접근제어가 필요하다. 본고에서는 이와 같은 요구사항을 만족시킬 수 있는 의료 정보의 특성 및 위협요소들에 대하여 조사 분석하고, 의료 정보 시스템 보안 정책 모델을 구현하기 위한 메커니즘을 제시한다.

• Journal of Korea Multimedia Society
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• v.5 no.3
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• pp.239-248
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• 2002

International Standard Organizations such as ITU(International Telecommunication Union) and IETF (Internet Engineering Task Force) are proceeding standardization for various applications and protocols to provide video-conference and multimedia conference services on a variety of networks. Remote device control among these protocols is provided with various capabilities as well as device control to multimedia conference. This protocol for remote device control is standardizing as H.282 recommendation which is specified as core service for the configuration and control of remote device to multimedia conference. The H.282 recommendation does not specify the use of a particular transport protocol. That is, T.120 multimedia conference uses T.136 and H.323 video conference uses H.283 for the transport of H.282 protocol. The introduced system in this paper is based on H.282 and is implemented to be capable of remote device control within the framework of H.323 using H.283. Also, it is shown that a variety of services in the specification of the standard are satisfied through experiments.

• The Transactions of the Korea Information Processing Society
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• v.3 no.3
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• pp.591-607
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• 1996

To support various multimedia applications. MuX server produces object-oriented and consistent interfaces for creation, copying, splitting, mixing and interleaving of streams. In this paper, we describes distributed connection structures and centralized connection structures which can be used in building a teleconferencing system using basic objects of MuX and compares merits and demerits of each structure from the viewpoint of multimedia related performance like delay and synchronization.

• Journal of the Korea Society of Computer and Information
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• v.3 no.2
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• pp.29-35
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• 1998

In this paper, the proposed audio/video control device for multiple user in the multimedia platform is changed for the better a disadvantage that must get one computer per participant to process a floor mode needed for interactive collaboration in the multimedia based distance education. It also proposed simulator of co-work environment that included multimedia data. This developed to proceed a multimedia distance education efficiently and sharing a computer among multiple users. Therefore, this is resulting in a reduction the cost needed to build a multimedia distance education system as well as totally simplified the organization of system. It also offers compatibility and generality, interfacing with the printer port of standard PC supporting the bi-direction mode.

• Proceedings of the Korea Association of Information Systems Conference
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• 2004.11a
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• pp.244-250
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• 2004

최근 정보화, 멀티미디어 시대를 맞이하여 기존의 음성 신호 이외에 화상 회의, 고화질 디지털 TV, 영상 전화와 같이 다양한 멀티미디어 정보를 고품질로 전송할 수 있는 광대역 밀리미터파 무선통신이 각광받고 있다. 밀리미터파 대역은 문화, 군사 및 항공우주 분야 등에 널리 활용될 수 있어 관련 소자 및 시스템 개발에 많은 노력을 기울이고 있으며 최근 상업적 필요성이 대두되면서 기지국과 가입자간의 통신로를 무선화하는 BWLL(Broadband Wireless Local Loop)과 무선 LAM 및 차량 충동방지 시스템 등 민수용 부문의 응용기술이 점차 보급됨에 따라 밀리미터파 기술은 민${\cdot}$군 겸용기술로 중요성이 부각되고 있다. 본 논문은 이동과 개인휴대 통신 시스템용 60GHz 밀리미터파 대역의 주요 응용 시스템은 도로, 철도 운송 시스템뿐만 아니라 실내${\cdot}$외용 밀리미터파 전파에 대해 소개한다.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.9
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• pp.527-535
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• 2004

Handling mixed workload in digital set-top box or streaming server becomes an important issue as integrated file system gets momentum as the choice for the next generation file system. The next generation file system is required to handle real-time audio/video playback while being able to handle text requests such as web page, image file, etc. Legacy file system provides only best effort I/O service and thus cannot properly support the QoS of soft real-time I/O. In this paper, we would like to present our experience in developing the file system which fan guarantee the QoS of multimedia stream. We classify all application I/O requests into two category: periodic I/O and sporadic I/O. The QoS requirement of multimedia stream could be guaranteed by giving a higher priority to periodic requests than sporadic requests. The proto-type file system(Qosfs) is developed on Linux Operating System.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.4
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• pp.312-333
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• 2005

SIP(Session Initiation Protocol) has been proposed for session control protocol of Internet multimedia communication system like VoIP(Voice over IP). SIP has complicated session control steps to support various kinds of audio and video formats and to assure service quality of real time data communication. Up until now, existing protocol analyzers can not provide such detailed information of SIP based communication system. In this paper, therefore, we propose a new protocol analyzer as a tool that can analyze and diagnose SIP based multimedia communication system throughout the session initiation, data exchange and session change steps. The propose traffic analyzer, which is called STAT(SIP based Traffic Analysis Tool), Is implemented on Winder's environment so that it is generally usable and extensible. Since STAT analyze low level packets captured via Ethernet broadcasting property, it is able to provide session status and real time traffic monitoring information without any affection to the communication system. The STAT which is implemented in this paper. therefore, is expected to be a useful tool for developing and managing of a SIP based multimedia communication system.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2006.11a
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• pp.95-98
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• 2006

디지털 멀티미디어 방송(Digital Multimedia Broadcasting :DMB)는 디지털 라디오 방송 시스템에 기반으로 한 최초의 휴대용 TV 서비스이다. 최근 제 78차 MPEG 회의에서 DMB 콘텐츠에 대한 멀티미디어 응용 포맷으로 DMB MAF에 대한 논의가 진행되었다. DMB MAF는 DMB 콘텐츠에 대한 ISO 파일 포맷을 기반으로한 DMB 단말기 간의 상호운영성의 지원 및 저장을 지원하기 위한 파일포맷이다. 본 논문에서는 DMB MAF를 위한 MPEG-21 IPMP 및 REL을 이용한 보호관리 기술에 대해 설명한다.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.7
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• pp.305-317
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• 2008

As a mobile computing environment is rapidly changing, increasing user demand for multimedia-over-wireless capabilities on embedded processors places constraints on performance, power, and sire. In this regard, this paper proposes color media instructions (CMI) for single instruction, multiple data (SIMD) parallel processors to meet the computational requirements and cost goals. While existing multimedia extensions store and process 48-bit pixels in a 32-bit register, CMI, which considers that color components are perceptually less significant, supports parallel operations on two-packed compressed 16-bit YCbCr (6 bit Y and 5 bits Cb, Cr) data in a 32-bit datapath processor. This provides greater concurrency and efficiency for YCbCr data processing. Moreover, the ability to reduce data format size reduces system cost. The reduction in data bandwidth also simplifies system design. Experimental results on a representative SIMD parallel processor architecture show that CMI achieves an average speedup of 6.3x over the baseline SIMD parallel processor performance. This is in contrast to MMX (a representative Intel's multimedia extensions), which achieves an average speedup of only 3.7x over the same baseline SIMD architecture. CMI also outperforms MMX in both area efficiency (a 52% increase versus a 13% increase) and energy efficiency (a 50% increase versus an 11% increase). CMI improves the performance and efficiency with a mere 3% increase in the system area and a 5% increase in the system power, while MMX requires a 14% increase in the system area and a 16% increase in the system power.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.3
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• pp.291-300
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• 1999

멀티미디어 서비스환경에서는 수백에서 수천의 클라이언트들이 하나의 서버에 접속되기 때문에 서버 결합이 미치는 영향이 상당히 크다. 이러한 결함은 단지 서버 자체의 장애로 끝나는 것이 아니라 그로 인해 서비스 제공자들에게 유형.무형의 막대한 재산상의 피해를 가져올수 있다. 본 논문에서는 멀티미디어 서버를 구성하고 있는 자원(프로세서, 디스크, 네트워크)의 결함 발생을 고려한 큐잉 네트워크 모델을 개발하였다. 복수개의 M/M/1 큐를 큐잉 네트워크로 연결하여, 각 자원에 대한 접근 및 서비스를 모델링하였으며, 각 자원에서의 서비스 시간 지연 비율(큐의 응답시간)의 조정을 통해서, 서버 자원의 결함 발생을 고려하였다. 고객 도착률과 자원 고장률 변동에 대한 서버 자원의 이용률과 큐의 길이를 구하여 효율적인 시스템 구성 자원의 부분별 용량을 산정하였으며 , 또한 데이터 패킷 응답 시간 분포 및 고장률 변화에 따른 시스템의 신뢰도 수준을 계산하였다. 이와 같은 서비스 시스템 성능에 관련된 파라미터 분석을 통하여 멀티미디어 데이터 서비스 수준 (Quality of Service)에 중요한 영향을 미치는 서버 설계 요소를 파악하였고, 시뮬레이터 패키지를 활용한 모의 실험을 통하여 개발된 큐잉 네트워크 모델의 정확성을 검증하였다.