• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 2006.07a
• /
• pp.534-534
• /
• 2006

• Journal of KIISE:Computing Practices and Letters
• /
• v.7 no.1
• /
• pp.24-37
• /
• 2001

This paper deals with our experience for the design and implementation of Transport and Session managers in the Integrated Streaming Service Architecture (IS SA) that was developed by the authors. The ISSA is a streaming framework that allows to develop integrated multimedia streaming applications such as VOD system in unicast/multicast and real-time broadcastOive-cast). It also facilities standard real-time transport protocols such as RTp(Real-Time Transport Protocol)/RTCP(Real-time Control Protocol) and RTSP(Real-Time Streaming ProtocoD that allows to user openness. The ISSA supports diverse media fonnats and is independent from underlying networks and operating systems, and compatible with the global real-time multimedia database system (BeeHive) so that streaming media are efficiently retrieved, stored, and serviced. The role of the Transport Manager is to do packetization and depacketization for the different types of multimedia data and delivers the packetized media data in real-time. The Transport Manager uses RTP protocol. The role of the Session Manager is to establish and control the media channel by using RTSP protocol and to deliver the database transactions for the multimedia database by using RTTP(Real-Time Transaction Protocol) protocol. Both the Transport and Session Manager are doing their functions through the network interface in the ISSA that allows developers to various network programming interfaces and provides flexibility to the system.

• Proceedings of the Korean Information Science Society Conference
• /
• 1998.10a
• /
• pp.674-676
• /
• 1998

본 논문에서는 H.263 비디오 코덱을 사용한 인터넷 스트리잉 서버와 클라이언트의 구현을 기술한다. 서버와 클라이언트간의 데이터 전송은 RTP 실시간 프로토콜을 사용하여 이루러진다. 스트리밍 서버는 저장된 H.263 파일 또는 입력 받은 비디오를 실시간으로 H.263으로 엔코딩하여 멀티캐스팅하고, 클라이언트는 멀티캐스트 세션에 접속하여 서버가 전송한 H.263 데이터를 받아 실시간으로 디코딩한다.

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.6
• /
• pp.1795-1802
• /
• 2000

In this paper, we propose an effective Noraebang service algorithm using multicasting technology. The goal of this proposed Noraebang service is to reduce the load of server as well as network resources and to enhance the performance of MOD. The effective Noraebang service algorithm proposes the new method that stores the post-ordered reserve songs in client's buffer in the order of request, not through the network and server, after the completion of the service pre-ordered requested song. The number of channel required in Noraebang service which used this algorithm can be decreased greatly when many songs re reserved, and the post-ordered songs can be serviced at real time by using buffer. The simulation results of this algorithm are confirmed that the performance of the proposed effective Noraebang service system increased significantly.

• The Journal of the Acoustical Society of Korea
• /
• v.16 no.6
• /
• pp.48-53
• /
• 1997

The multicasting of MCS(Multicast Server) requires a effective traffic control scheme to prevent buffer overflow on ATM subnetworks. This paper considers MCS multicasting to TCP packets, and propose EPD + SPD scheme(Early Packet Discard-same Source Packet Discard) using common buffer. When the threshold of output buffer is reached, MCS drops an entire packet prior to buffer overflow, so that corrupted packets will not be transmitted by the server. And SPD scheme show that the EPD + SPD results in higher TCP throughput than that of tail drop and EPD + DFF.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2001.04a
• /
• pp.107-110
• /
• 2001

화상회의시스템이란 영상 및 멀티미디어를 활용하여 원격 회의를 가능하게 하는 정보전달 매체로 가격이 저렴해지면서 학교 현장에 보급되기 시작하였다. 이 시스템의 활용 범위가 확장되어 교육청과 학교간의 회의뿐만 아니라 실시간 원격연수에도 활용이 가능하게 되었다. 그러나 현장의 교사들은 화상회의 시스템에 대한 지식과 응용 프로그램의 사용 경험 부족으로 적극적인 활용에 어려움을 겪고 있다. 본 연구에서는 현재 학교에 널리 보급되어 있는 MCU방식과 최근 새롭게 개발된 IP 멀티캐스팅 방식의 원격교육 시스템에 대한 장단점을 비교하고 분석하여 교육 현장에 적합한 화상회의시스템에 대한 평가를 할 것이다. 그리고, 실시간 원격교육 프로그램을 위한 화면의 설계 결과와 화상회의 시스템과의 인터페이스 방법에 대한 설계 결과를 제시할 것이다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.11C
• /
• pp.51-63
• /
• 2001

According to the popular use of the multimedia services in distributed environments, the need for the variable multimedia communication technologies have been presented today. In order to support the efficient transmission multimedia streams, the multicasting, and the interoperability between multimedia applications in distributed environments, the development of the open exclusive multimedia communication systems and the provision of the control and management methodologies for media streams have been required. In order support the realtime transmission of multimedia stream in distributed environments. the protocols such as RTP, RSVP, and RTSP have been standardized. For supporting the interoperability between multimedia applications and the control and management of streams, the distributed processing platforms such as CORBA by OMG and DSM-CC by DAVIC were published. In this paper, we introduce the CORBA-based distributed multimedia communication system which support the realtime transmission, control, and management of multimedia streams and provide the interoperability between multimedia applications. Finally, we present the QoS measurement results by the interoperability between our systems and VoD systems.

• Proceedings of the Optical Society of Korea Conference
• /
• 1995.06a
• /
• pp.201-209
• /
• 1995

광의 초고속성의 본질을 이용한 시간다중 공간분할 광교환 시스템이 처음으로 구현되었다. 단순한 공간분할 광교환방식에 비해 뛰어난 확장성과 간단한 하드웨어로 화상 및 음성신호의 지점대 지점간의 교환 및 멀티 캐스팅의 서비스가 가능하다. 스위칭 사간, 수용 가입자 수, 동기분제, 손실과 광출력의 분배, 광압축 등을 통하여 본 시스템의 특성을 분석해 본다.

• Smart Media Journal
• /
• v.2 no.1
• /
• pp.8-16
• /
• 2013

The significant enhancement of the edge portion of computer networks including user-side machines and last mile network links encourages the research of the overlay network based data dissemination systems. Varieties of overlay network based data dissemination systems has distinct purposes, and each of them has a proper structure of an overlay network and a efficient communication protocol. In this paper, overlay network based data dissemination systems for Flash Dissemination, whose target is the distribution of relatively small size data to very large number of recipients within very short time, are explored. Mainly two systems, RECREW and FaReCAST, are introduced and analyzed in the aspects of design considerations for overlay networks and communication protocols. According to evaluations for flash dissemination scenarios, it is observed that the proposed overlay network based flash dissemination systems outperforms the previous overlay network based multicasting systems, in terms of the reliability and the dissemination delay. Moreover, the theoretical analysis of the reliability of data dissemination is provided by analysing FaReCAST.

• Journal of KIISE:Computing Practices and Letters
• /
• v.5 no.3
• /
• pp.326-335
• /
• 1999

본 논문은 분산환경에서 객체 공유를 통하여 서로 다른 전문가들의 협력 작업과 개발팀 구성원간에 정보 공유, 상호의존적 업무 수행, 공동의 산출물 생성등의 작업을 지원하는 공유시스템의 설계 및 구현에 관한 것이다. 분산 공유 시스템은 ITU-T의 멀티미디어 회의 국제 표준인 T.130 시리즈를 근간으로 회의 세션관리, 동적 참여와 발언권 제어를 하는 회의 제어기, 멀티 캐스팅 통신을 지원하는 다자간 통신서비스, 응용프로그램 객체를 공유하게 하는 공유 기법으로 중앙 집중형 구조를 갖는 GUI 공유 방식과 복제 구조를 지원하기 위하여 이벤트 공유 방식을 지원하는 원격제어기가있으며 사용자 정보와 공유시 필요한 정보 관리를 위한 데이터베이스 프로세서로 구성되어 있다. 따라서 각 구성요소에 대한 설명과 전송량이 많은 GUI공유기에서 시스템 성능 향상의 주된요소인 네트워크 부하를 줄이는 셀(cell)단위의 전송 메커니즘에 대하여 기술하고 있다.