• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.5
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• pp.1241-1248
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• 1998

The multicast scheme can improve the efficiency of multimedia retrieval service system, assuming that video transmission speed is faster than the playback rate and the store-and-play scheme. To best exploit the multicast benefits under bandwidth heterogeneous environment, we develop a multicast scheduling algorithm called MTS(Maximum Throughput Scheduling) which tries to maximize the amount of information transferred at each scheduling with subgrouping method. The MTS method compromises the multiple unicast method and the multicast method with lowest transmission rate. we compare the performance of MTS with that of MMS(Most Multicasting Scheduling) and EDS(Earliest Deadine Scheduling) via computer simulation. The performance results show that the MTS requires less number of service handlers to service the same number of subscribers.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1997.11a
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• pp.33-38
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• 1997

최근에 윈도 NT를 탑재한 고성능 PC의 등장, ATM 카드, 실시간 MPEG 인코더/디코더 보드의 개발 등, 컴퓨터 업계의 눈부신 발전으로 영상 데이터를 네트워크에 분산 저장하고, 브라우저를 사용하여 필요한 자료를 검색, 활용, 편집할 수 있는 멀티미디어 방송 제작 환경 구축이 가능하게 되었다. 본 연구에서는 실시간 영상 전송을 위해 ATM 망을 구성하고, 네트워크상에서 효율적인 검색을 위한 클라이언트/서버 모델을 제시하며, 자동 인덱싱 기능을 가진 동영상 검색 브라우저 시스템을 구현해 보고 앞으로의 연구방향을 검토하였다. 모든 사용자 인터페이스 편리한 윈도 GUI 환경을 사용하므로 사용자는 프로그램을 쉽게 사용할 수 있으며, 프로그램 전체는 C++를 사용하여 클래스 단위로 제작되어 향후 시스템 개발이 용이하게 설계되었다.

• Journal of Korea Multimedia Society
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• v.3 no.5
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• pp.479-494
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• 2000

Although the proliferation of real-time multimedia services over the Internet might indicate its successfulness in dealing with heterogeneous environments, it is obvious, on the other hand, that the internet now has to cope with a flood of multimedia data which consumes most of network communication channels due to a great deal of video or audio streams. Therefore, for the purpose of an efficient and appropriate utilization of network resources, it requires to develop and deploy a new scalable transmission technique n consideration of respective network environment and individual clients computing power. Also, we can eliminate the waste effects of storage device and data transmission overhead in that the same video stream duplicated according to QoS. The purpose of this paper is to develop a technology that can adjust the amount of data transmitted as an MPEG video stream according to its given communication bandwidth, and technique that can reflect dynamic bandwidth while playing a video stream. For this purpose, we introduce a media scalable media decomposer working on server side, and a scalable media composer working o n a client side, and then propose a scalable transmission method and a media sender and a media receiver in consideration of dynamic QoS. Those methods proposed her can facilitate an effective use of network resources, and provide multimedia MPEG video services in real-time with respect to individual client computing environment.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.12 no.1
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• pp.5-23
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• 2001

본 논문의 목적은 대용량의 디지털저작물을 저장하는 웹기반의 교육전문전자도서관을 구축하는데 있어서 가장 중요한 요소중의 하나로써 고려되어지고 있는 저장구조를 설계하는데 있어서 이용자의 요구에 대한 신속한 대응, 관리자의 효율적인 관리 서비스제공자에 있어서 저장장치에 대한 경제성 등을 기준으로 가장 적절한 방법을 제시한다. 본 논문에서는 현재 가장 일반적인 방법인 버스부착형방식과 NAS에 대한 장, 단점을 분석하고 이에 대한 새로운 대안으로서 제시되고 있는 SAN방식에 대한 특징을 파악하여 교육전문 전자도서관과 같은 대용량의 디지털데이터를 저장해야 하는 대용량저장시스템에 있어서 가장 효율적인 저장구조 방식을 제시한다. 즉. 서버와 저장장치사이의 I/O처리속도, 관리의 용이성, 경제성 등의 저장구조방식을 선택하는데 있어서 중요한 요소들을 기준으로 하여 실제 시스템을 구현하여 이를 직접 실험을 통하여 측정하여 보았다.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.6
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• pp.674-685
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• 1999

MIDAS-II는 한국전자통신연구원에서 개발한 바다 DBMS의 저장 시스템이다. MIDAS-II 볼륨은 데이터의 논리적 저장 단위인 파일을 저장하는 영역을 가리킨다. 본 논문에서는, MIDAS-II가 대용량 멀티미디어 데이터 서버의 저장 시스템으로 기능하도록 광 디스크 쥬크박스 또는 테이프 라이브러리와 같이 복수 개의 저장 매체 (platter , 예를 들어 디스크 또는 카트리지 테이프)로 구성된 Tera 바이트 급의 3창 저장 장치를 장착할 경우 이를 위한 볼륨 구조의 설계 및 구현에 대해 기술한다. 본 논문에서 제안하는 볼륨 구조는 3차 저장 장치 접근 시 성능 제고를 위하여 디스크 캐쉬 영역을 두고 있으며, 3차 저장 장치의 저장 매체별 관리 기능을 제공한다. Abstract MIDAS-II is the storage systemfor BADA DBMS developed at ETRI. A volume of MIDAS-II is the area where the files, the logical unit for storing data, are stored. This paaper describes the design and implementation of a new MIDAS-II volume structure for the tertiary storage device such as an optical disk juke box or a tape library equipped with multiple platters(disks or cartridge tapes, for example ). Incorporating thetertirary storage device of the order of tera bytes into MIDAS-II enables it to function as a storage system for a massive amount fo multimedia eata server. The volume structure for the tertiary storage device proposed in this paper features disk caching for performing improvement and direct control of theindividual platter.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.355-359
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• 2000

This paper presents design of an advertising E-commerce (electronic commerce) serve. using push technology which provides clients with multimedia information such as text, audio and video according to their setting information. In the most of existing E-commerce system, users visit the web site in person, see and buy goods. In this paper we show the new E-commerce format: Clients select a field of advertisement of what they want to see on the browser, then EC server sends the clients moving advertisements at regular intervals. Subsequently, the users see advertisements and buy goods. The server of this system was designed using push server that saves moving advertisements in the database and sends the user-specific advertisements to users. The system designed in this study is very an active system contrary to existing passive E-commerce systems.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.4
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• pp.426-439
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• 1999

본 논문에서는 웹(World Wide Web)에서 사용자가 손쉽고 편리하게 이용할 수 있는 멀티미디어 대중교통 안내시스템 개발 경험을 소개한다. 개발된 시스템은 클라이언트와 서버 시스템, 경로탐색 시스템, 교통정보 저장 시스템, 노선 및 정류장 관리 시스템으로 구성되어 있다. 클라이언트에서 작동되는 사용자 인터페이스는 직관적으로 이해가 쉽고, 사용이 편리하며 인터액티브한 멀티미디어 대중 교통안내 서비스를 제공한다. 서버 시스템은 교통정보 수집 시스템으로부터 입력되는 데이타와, 경로탐색 시스템, 교통정보 저장 시스템과 연동되어 클라이언트의 요구사항을 처리하고 그 결과를 사용자에게 돌려준다. 수정된 A* 알고리즘을 이용하는 경로탐색 시스템은 최적경로를 탐색하며, 교통정보 저장 시스템은 현재 교통상황, 정류장, 노선, 지도 등의 정보를 저장한다. 노선 및 정류장 관리시스템은 시스템 관리자가 노선 또는 정류장 관리를 서버 화면의 지도상에서 효율적으로 수행할 수 있는 도구이다. 본 논문에서 다루는 대중교통 안내시스템은 Java로 구현하였기 때문에 확장과 이식이 용이하며, 시스템 유지보수 비용이 적게 드는 장점을 가지고 있다. 그리고, 웹 브라우저가 동작되는 환경에서는 어디서나 쉽게 접근이 가능하며 향후 구축될 Intelligent Transportation Systems(ITS)의 한 모듈로써 바로 작동될 수 있을 뿐만 아니라, 현재 인터넷상에서 제공되는 다양한 서비스와도 연동이 가능하다.Abstract This paper introduces our experience for developing a public transportation guidance system, which facilitates the World-Wide Web(WWW) to provide users with easier access and use. The proposed system is composed of four subsystems: client/server system, path search system, traffic data storage system, and traffic raw-data management system. The user interface in clients utilizes Java to furnish users with multimedia data accessibility and interactivity. The server processes clients' requests based on the traffic data coming from remote sensing devices and interacts with the path search system and traffic data storage system to provide users with the results. The path search system, which uses a modified A* algorithm, produces optimal solutions based on dynamic traffic data. The traffic data storage system stores the current traffic information together with the geographical information about the b$us_way routes. The traffic raw-data management system is a graphical user interface which enables the system manager to handle the traffic information easily on the map in the terminal screen. The system has considerable benefits such as portability, scalability, and flexibility since it is implemented using Java. Also, it can be extended to an integrated Intelligent Transportation Systems(ITS) which includes a variety of information on the Internet as well as traffic information.n.

• The Transactions of the Korea Information Processing Society
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• v.6 no.4
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• pp.877-890
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• 1999

In this paper, a multimedia mail including video, sound, graphic data has been proposed as the next generation mail of the text based mail. In order to develop the multimedia mail, the most outstanding problem is the fact that the multimedia data are too huge to send them to the receiving end directly. The fact of big data may cause many problems in both transferring and storing the data of the multimedia mail. Our main idea is to separate between a control program for the multimedia presentation and multimedia data. Since the size of a control program is as small as a plain text mail, it has no problem to send it attached to the internet mail to the receiver directly. Instead, the big multimedia data themselves may remain on the sender's computer or be sent to a designated server so that the data may be transferred to the receiver only when the receiver activates the play of the multimedia mail. In this scheme, our research focus is paced on the buffer management and the thread scheduling for the real time play of the multimedia mail on internet. Another problem is to provide an easy way of editing a multimedia presentation for an ordinary people having no programming knowledge. For the purposed, VIP(Visual Interface Player) has been used and the results or multimedia mail implemented on LAN has been described.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.2 s.302
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• pp.39-48
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• 2005

In this paper, we implement the multimedia remote control system by using existing internet service or wired online. We also provide user-friendly convenient environment with developed application program named EzPlay and PC-EPG. The multimedia remote control system consists of integrated wireless transceiver of PC and TV connected USB type and the users can easily use lots of contents because EzPlay program provides appropriate UI mode on the PC and TV screen. The unposed system can operate real-time playing, reserved video receding and data storing function using internet mesh based on signal detecting control theory. The PC-EPG system is implemented by server/client web program and the client program based on visual C++/MFC processes data storing in client computer through TCP/IP. It also provides intelligent function that constructs database according to user's preference.

• Journal of Korea Multimedia Society
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• v.8 no.3
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• pp.355-361
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• 2005

This paper proposed a system collecting image information by agents in multi-threaded environment and then retrieving them with content based image retrieval. This system uses multi threads to retrieve web information effectively, then improves efficiency of CPU cycles to reduce latency time, which is the time requesting queries, executing communication processing 4hat the retrieval agents perform and filtering the retrieval results. Also, the agents for image retrieval use Java language, which is platform independent, to be suitable for distributed environment. Using JDBC to save the retrieved images, the agents are connected to database. The images themselves are stored in distributed agents' databases, and only the image indexes are stored in an index server so that the efficiency of storage and retrieval time can be improved.