• Journal of Korea Multimedia Society
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• v.12 no.5
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• pp.653-663
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• 2009

Synchronization between media is an important aspect in the design of multimedia communication-system. This paper proposes a precise media synchronization mechanism for video and audio transport over IP networks. To support synchronization between video and audio bitstreams transported over IP networks, RTP/RTCP protocol suite is usually employed. To provide a precise mechanism for media synchronization between video and audio, we suggest an efficient media synchronization algorithm based on NPT (Normal Play Time) which can be derivable from the timestamp information in the header part of RTP packet generated for the transport of video and audio. In the proposed method, we do not need to send and process any RTCP SR (sender report) packet which is required for conventional media synchronization scheme, and accordingly could reduce the number of required UDP ports and the amount of control traffic injected into the network.

• The Transactions of the Korea Information Processing Society
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• v.3 no.7
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• pp.1858-1867
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• 1996

This paper describes a platform for video conferencing on Information Super Highway. In this paper we de-sign a Multi-Multicast Server(MCS) and the platform. The platform uses Multi-MultiCast Server for multitasking IP Multicast data on IP over ATM. Based on Multicast Address Resolution Server (AMRS) which was proposed in this paper the platform maps from D class IP addresses to ATM addresses. MARS handles a recovery in case of MCS down. This paper also presents a solving mechanism for handling botteneck by using the MCS.

• Information and Communications Magazine
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• v.20 no.10
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• pp.121-130
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• 2003

1997년 활동을 시작한 APAN-KR (Asia Pacific Advanced Network - Korea) Technology Area 활동을 계승하여 2003년 초에 재구성된 ANF (Advanced Network Forum: 한국첨단망협회) Application Technology Area에 대한 전반적인 소개에 이어서 VoIP (voice over IP), DV/VC(digital video / video conferencing) 및 P2P(peer to peer)로 나누어진 각 세부 WG (working group)들의 소개, 활동 내용, 향후 계획 등을 살펴본다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2003.10a
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• pp.329-342
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• 2003

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11a
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• pp.53-56
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• 2002

VoIP(Voice over IP) 기술은 다양한 인터넷 응용 서비스 보급의 대중화에 기여한 주요 통신기술의 하나이다. 이에 따라 인터넷 이용자가 급격히 증가하고 인터넷 전화의 수요가 증가하게 되었다. 특히, 음성 뿐만 아니라 영상에 대한 기술이 접목되어 V2oIP(Voice and Video over IP) 라 일컬어 지는 기술이 보급되면서, 인터넷 영상전화에 대한 대중화가 이루어 지고 있다. 한편, 다양한 인터넷 응용 서비스 보급의 대중화에 따른 가정 내에서의 네트워크 환경 또한 부각되고 있어 정보가전분야에 큰 변화가 일고 있다. 이에 홈서버 중심의 홈네트워크환경이 구축된다. 따라서, 기존의 pc 를 단말기로 한 인터넷 환경 및 제반 응용 서비스가 그대로 홈서버 중심의 홈네트워크환경으로 옮겨져야 할 필요가 있다. 본 논문에서의 전체 시스템은 임베디드 리눅스 기반인 Qplus 운영체제를 기반으로 하는 홈서버상에 HoCoS(Home Collaboration Service) 시스템이 탑재되며, 이 시스템은 크게 영상전화 시스템과 공동작업 시스템으로 구성된다. 본 논문에서는 상기 시스템 중 SIP(Session Initiation Protocol)기반의 홈서버용 영상전화 시스템에 대한 설계 및 구현에 대해 기술하고자 한다.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.166-168
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• 2001

최근 인터넷 이용의 증가는 전송 링크의 광대역 지원과 멀티미디어 트래픽 QoS 보장 등의 문제 해결을 필수적으로 요구하게 되었다. 또한 현재 인터넷 IP 서비스에서 한 단계 향상된 서비스, 즉 가상 사설망(Virtual Private Network) 서비스나 Voice over IP, Video over IP, 웹 호스팅, 전자 상거래 제공 등이 현실적인 문제로 대두되면서 이를 지원할 수 있는 네트워크 구성 요소의 필요성은 증가하고 있다. 이를 해결하기 위하여 IP와 ATM의 통합으로 MPLS 기술 개발이 활발히 진행되고 있다. MPLS 시스템이 현재 IP 네트워크에서 지원하는 것 이상으로 보다 유용한 운용(Operation), 관리(Administration), 유지보수(Maintenance) 기능을 지원해야 하기 때문에 네트워크 운용과 관리(OAM)는 매우 중요하다. 본 논문에서는 ACE2000 ATM 교환기를 기반으로 하는 MPLS 시스템에서 OAM 계층과 라벨을 고려함으로써 ATM 시스템의 운용관리 기능과 연계처리 가능한 MPLS 시스템에서의 통합 운용관리 기능을 설계하고 구현한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.134-144
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• 2009

The Ubiquitous/Unified Communication Platform supports various multimedia communication tools such as VoIP, Email, Unified Messaging, Instant Messaging, Web Conferencing, Audio/Video Communication etc. In this paper we introduced the main functions and architecture of the Unified Communication Platform and we researched on the function analysis and design of the VoIP System that supports PC-to-PBX/PSTN Phone and PBX/PSTN Phone-to-PC communications through the connectivity and interoperation with PSTN.

• Korean Journal of Human Ecology
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• v.15 no.6
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• pp.961-971
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• 2006

The purpose of this study was firstly to provide fundamental data on the activation for the IP-based video phone for the special consumer related to the physically handicapped; secondly to inform empirical data for the consumer public policy in the information technology market, specially for the deaf people. The results of study showed that consumer needs extend to not only simple voice communication for general consumers but also special demands for both the handicapped and the elderly. This study also indicated that VoIP's characteristics of technology would be easily applied to the TRS or VRS which can be adapted to the special consumer market so that VoIP service would be optimal technology for the special consumers like the deaf. In order to successfully implement TRS & VRS business, the paper proposed as follows; 1) the provision of VoIP service enable to satisfying consumers in special market such as the deaf market and the elderly market, 2) the necessity of supporting policy by the related law, and 3) the construction of the system inducing interests from the market participants.

• Journal of Internet Computing and Services
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• v.10 no.6
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• pp.27-36
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• 2009

PSTN (public switched telephone network) provides voice communication service, whereas IP network provides data oriented service, and we can use IP network for multimedia transport service (e.g. voice over IP service) with economic price. In this paper, we propose RoIP (robot on IP) service scenario, signaling call flow, and implementation to provide home automation and monitoring service for remote site users. In our scheme, we used a extended SIP (session initiation protocol) for signaling protocol between remote site users and home robots. For our bearer transport control, we implemented H.263 video codec over RTP (real-time transport protocol) and additionally DTMF (dual tone multi-frequency) transport for robot actuator control. We implemented our scheme on home robots and experimented with KTF operator network, and it shows good communication quality (average MOS = 9.15) and flexible robot controls.

• ETRI Journal
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• v.38 no.5
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• pp.838-846
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• 2016

The objective of digital broadcasting has evolved from providing a plain video service to offering a realistic visual experience. Technologies such as 3DTV and UHDTV have been suggested to achieve this new objective by providing an immersive and stereoscopic visual experience. However, owing to the high bandwidth requirements of such services, the broadcasting industry has faced a challenge to find a new transport mechanism for overcoming the bandwidth limitation. The standardization organizations, the Advanced Television Systems Committee, Digital Video Broadcasting, and Telecommunications Technology Association, have been working on the integration of broadcasting and a broadband network (IP) to resolve the bandwidth issue of realistic video services. This paper introduces a frame-level timeline synchronization and transport system target decoder model for providing a stable 3DTV service over a hybrid network. The experimental results indicate that the proposed technologies can be successfully adopted as a reference model in a broadcast-broadband hybrid 3DTV service and other IP-associated hybrid broadcasting services.