• The Transactions of the Korea Information Processing Society
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• v.4 no.6
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• pp.1601-1614
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• 1997

In this paper, We suggest a technique for delivering frame(CM transfering unit) based CM data streams from MOD servers to clients on ATM-LAN environment. The term 'frame' indicates the CM transferring unit. In detail, each clients try to adapt native ATM-specific service which can be connected directly from application layer to AAL without convening transport and IP layer. Also, we suggest and show result of implementation about transparent browsing mechanism using navigation server, session setting procedures using PVC between server and clients, application, AAL and QoS negotiation and reservation procedure, splitting and reassembling algorithm for frames over MTU size.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9B
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• pp.1652-1660
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• 1999

One of the most important goals in VOD servers is to provide services to more clients with services which clients request. In order to provide service efficiently and rapidly, though considering a few of policies, efficient placement of data when they are stored is direct cause to improve efficiency of retrievals. In this paper, we propose a efficient placement policy, encoded video data being stored in clustered VOD servers. In the proposed placement policy, partitioning a large disk array into smaller disk groups which consists of a few of disks with similar performances, specially disk I/O bandwidth. In last chapter, we compare proposed placement policy with conventional policies, and show the results of improved performances with proposed policy.

• Convergence Security Journal
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• v.15 no.1
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• pp.83-89
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• 2015

In the wide area surveillance system including many CCTVs, application for remote realtime monitoring is designed and implemented. The applications using Xcode provide secure administrator interface from headquarters. Through the efficient and intuitive interface, it delivers real-time context reports and inference results. For the user convenience, it includes push alarm of events, SNS, Media streaming service for real-time monitoring uses Wirecast and Wowza media server. Wowza stream engine provides URL accommodating development specification. Mobile devices can receive real-time stream data. Performance evaluation in the processing is provided.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.4
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• pp.313-321
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• 2005

Drag coefficient is one of the critical design factors to quantify the piston effect in vehicle tunnels. Several problems are raised on the drag coefficient currently applied for the ventilation system design; unverified adoption of the projected frontal area of the vehicle from the foreign study in the past, and lack of consideration for the slip-streaming effect. This study aims at better estimation of the traffic-induced ventilation force in the local tunnels. Values for the projected frontal area of the vehicles running on the local roads at present are proposed and results of an extensive CFD study are studied on the slip-streaming effects in various traffic conditions to quantify $K_{blockage}$ and the drag coefficient in the domestic tunnels.

• Journal of Korea Multimedia Society
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• v.8 no.5
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• pp.707-741
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• 2005

In the multimedia streaming technology, the unicast method require additional cost by an increase traffic according to increase a number of users. The multicast method can solve this problem, but it don't have connection and control information of clients. Now, the most routers support only unicast. Also it has a problem with an exchange of service in other ISP. This paper proposes traffic agent system which is applied unicast and P2P(Peer to Peer) for distance video teaming to overcome this problem. The proposed system decrease the traffic of stream server by control agent, and cut down expenses of network. This system is tested under the distance video leaning using JMF and application software.

• The Transactions of the Korea Information Processing Society
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• v.6 no.8
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• pp.2042-2049
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• 1999

In contrast to traditional data communication, the multimedia communication must support variable requirements to multimedia application service. Specially, it is a critical issue that the synchronization supports a continuous and temporal relationship media playout in a distributed environment. But the continuously generated media in source can't guarantee the constant interval on playout for the destination due to the inconsistent network transmission delay and transmission error. In this paper, we introduce a intramedia synchronization mechanism for the continuous and synchronous playout of multimedia stream such as audio and video across a communication network. The proposed mechanism is based on the user defined QoS(Quality of Service) and the playout correction algorithm to guarantee the continuous media playout at the receiver.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.8C
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• pp.703-711
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• 2007

In this paper, we propose a multi-view coding(MVC) algorithm with considering view scalability. The proposed algorithm has a high compression efficiency by reducing inter-view redundancy through inter-view decomposition, and adaptively reconstructs a multi-view video from an encoded bit stream. Furthermore, a reference view can be decoded by a traditional H.264/AVC, and the other views are adaptively decoded at the receiver by filtering to support view scalability. Experimental results show that the proposed algorithm performed better than the conventional H.264 codec even though it offers the view scalability.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.6
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• pp.737-741
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• 2010

When implementing Enhanced TV services, the time synchronization between the video stream that forms the background and the data contents overlaid on audio/video is an important issue. Currently, however, the basic method of synchronizing the data in the MPEG-4 environment is based on absolute time values. For more efficient synchronization when developing Enhanced TV content, this paper proposes a content-based synchronization in which the data content varies depending on the video content. The proposed content-based synchronization method is implemented by defining BIFS nodes more widely, based on scene keywords, and then using the metadata of MPEG7.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.462-466
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• 2007

본 논문에서는 데이터 방송 환경에서의 DSM-CC 관련 Object Carousel Manager를 구현하고, 성능향상을 위한 캐싱 기법을 제안한다. Object Carousel Manger 구현은 다음과 같은 순서로 이루어진다. 먼저, 방송스트림에서 해당 PID별로 얻어온 모듈을 캐시에 저장한 후, 모듈에서 BIOP 메세지 오브젝트별로 분석한 뒤 파싱 한다. 그런 후, 파싱된 BIOP 메시지 오브젝트를 해당 서비스 게이트웨이, 디렉터리. 파일로 변환해준다. 마지막으로, 변환된 파일시스템에서 해당하는 Xlet Application을 실행시켜 주게 된다. 시스템성능 향상을 위해서 제안하는 캐싱 기법은 다음과 같다. DII의 Caching Priority Descriptor를 이용하여, Object들을 포함하고 있는 각각의 모듈에 대해서 Version Number를 Checking하는 주기인 Transparency_level을 부여하고, Application 실행 시 보여 주는 화면 순서대로 필요한 모듈에 대해 우선순위를 부여하여, 캐시에 업데이트 시 이를 반영하여, 시스템 전체의 성능을 향상시킨다.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.473-476
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• 2007

최근 방송 통신 기술의 눈부신 발전에 힘입어 등장한 데이터 방송(Data Broadcasting)은 시청자에게 영상과 음성환 아니라 기존에는 접할 수 없었던 다양한 서비스들을 제공하고 있다. 이런 데이터 방송을 수신하기 위해서는 TS로부터 데이터를 추출하고 처리할 수 있는 미들웨어(middleware)가 포함된 셋탑박스(set-top box)가 필요하다. 그리하여 MHP, OCAP, ACAP 등 여러 데이터 방송 시스템의 미들웨어 표준 규격이 정의되었다. 그 중 MHP의 경우, OpenMHP라는 오픈 소스 프로젝트를 통해 PC 상에서 간단하게나마 MHP API를 테스트 해 볼 수 있는 환경을 제공해 주고 있다.[1] 하지만 셋탑박스 내에서 하드웨어를 이용하는 작업들은 거의 구현되지 못 했기 때문에 테스트에 있어 극히 제한적일 수밖에 없었다. 따라서 본 논문에서는 소프트웨어적으로 셋탑박스 환경을 에뮬레이션 해주는 Virtual Set-Top Box(VSTB)를 설계, 구현하였다. 셋탑박스가 없는 환경이나 간단한 시뮬레이션이 필요한 경우, 실시간 스트림 역다중화와, 파싱, 필터링 작업등이 지원되는 가상 셋탑박스 시스템을 통해 MHP 미들웨어 API를 테스트하는데 유용한 역할을 할 수 있을 것이다.