• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.1A
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• pp.57-65
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• 2007

The overlay multicast that has been recently presented as IP alternative for the IP multicast has been getting much persuasion by the computing power of the hardware and the advancement of the network techniques to enforce Routing in application-level. In an overlay multicast, the system resource and the network bandwidth must be utilized efficiently to service real-time HDTV images. Specifically, the system must consider the delay and the jitter that can be incurred at the application-level. In this paper, we implement a server and a client to broadcast HDTV, in the session composed by the existing overlay multicast protocol. The broadcasting server performs the service using a TV tuner, An HDTV camcorder, and files, clients constituting a multicast group relay the received data to other clients. At this time, the information that the clients report periodically, including their delay and the network state, to the server is used as an important information to maintain an overlay session. The implementation is based on the DirectX and its performance is evaluated by the LAN test bed that has been set.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.682-685
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• 2007

P2P 기술의 발달로 기존 클라이언트-서버 형태인 중앙 집중형 방식의 단점을 극복하고 있다. 이러한 P2P 기술의 진화로 P2P 응용 기술에 대한 많은 발전이 있었다. 현재 P2P 구조에서 사용자는 P2P 네트워크에 참여하여 자신이 원하는 자료를 찾는 검색과정이 필요하다. 본 논문은 이러한 과정을 최소화하여서 검색과정을 줄일 수 있는 방법을 다룬다. P2P 네트워크에 존재하는 서비스 프로파일 목록들을 서비스를 제공하는 주체가 서비스를 소비하는 주체에게 보내주게 된다면 사용자는 최신의 서비스 목록을 유지하여 서비스 목록 검색 시간을 최소화 시킬 수 있다. 본 논문에서는 P2P 오버레이 네트워크상에서의 서비스 푸시 시스템에 대한 정의, 각 피어들의 행동모델을 정의 및 시스템 설계에 대해서 소개한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.11a
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• pp.237-240
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• 2004

본 논문에서는 URL 동기화 기능을 갖는 멀티미디어 공동 작업 환경에서 오류 상호 인지 및 제어에 대하여 기술한다. 웹 기반 공동 작업 환경에 참여하는 모든 사용자들은 사용자의 명령, 또는 오류가 발생된 응용들을 제어 가능하며 상호 작용 가능하다. 상호 인지란 상호 작업 이해, 참여자 관계 설정 등 결합이라는 구현 기술을 말한다. 파일 공유, 윈도우 복사, 윈도우 오버레이, 또는 윈도우 공유 등 인지의 구현 방법이 있는데 웹 기반 멀티미디어 공동 작업 환경에서 오류 발생시 오류도 하나의 응용으로 취급하여 처리한다. 즉, 윈도우 오버레이 기능에 세션 제어, 발언권 제어 등을 추가한 윈도우 공유 방법을 제안한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.10
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• pp.1397-1402
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• 2021

The overlay2 file system is one of the union file systems that mounts multiple directories into one. The source directory used for this overlay2 file system mount has a characteristic that it operates independently of the write-able layer after mounting, so it is often used for container platforms for application delivery. However, the overlay2 file system has a security vulnerability that the write-able layer is also modified when file in the source directory is modified. In this study, I proposed the overlay2 file system protection technology to remove the security vulnerabilities of the overlay2 file system. As a result of empirically implementing the proposed overlay2 file system protection technology and verifying the function, the protection technology proposed in this study was verified to be effective. However, since the method proposed in this study is a passive protection method, a follow-up study is needed to automatically protect it at the operating system level.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.514-516
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• 2005

국내외적으로 흠 네트워크의 보급이 활발히 이루어지고 있으며, 이러한 홈 네트워크는 현재의 데이터 네트워크 및 제어 네트워크 중심에서 향후 다수의 미디어 콘텐츠를 보유하는 A/V 흠 네트워크로 발전될 전망이다. 이런 환경 하에서 사용자들은 현재 P2P 파일 공유 시스템에서 이루어지는 것처럼 자신들의 관심에 기초하여 다른 홈 네트워크에 있는 미디어 콘텐츠들을 공유할 것으로 보인다. 본 논문에서는 이처럼 예상되는 사용자들의 요구를 효율적으로 지원하기 위하여 사용자들의 관심 사항을 효과적으로 반영하며 보장된 응답시간 내에 미디어 콘텐츠 검색을 제공하기 위한 P2P 오버레이 네트워크 구성 방안인 IGN (Interest-based Grouping Network)을 제시한다. Chord와 드브루인 (do Bruijn) 그래프로 구성되는 IGN은 structured P2P의 세밀한 검색 지원에 대한 한계와 unstructured P2P의 보장되지 않은 최대 검색 시간의 문제점을 해결하며, 보장된 최대 검색 시간 내에 사용자들의 관심 사항을 세일하게 반영하는 검색을 지원할 것으로 예상된다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.7
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• pp.879-884
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• 2020

In the conventional video file system, videos are stored in a high performance server which has mass storage hard disks or disk arrays. For 3D internet broadcasting, real time operations are required to transmit video files to many clients. This paper describes the design of the 3D internet broadcasting system which can provide realtime streaming service to many users in the 5G environment. In reality, unicast is used to transmit multimedia contents over the internet rather than IP multicast since IP multicast has its own drawbacks in deployment, security, maintenance and so on. In addition, multimedia broadcasting service system like VoD has difficulties in applying to 3D internet broadcasting system since it requires a large amount of system and network resources. In this work, we develop a 3D internet broadcasting system which can construct effective data delivery by minimizing performance-degrading factors.

• Journal of Digital Contents Society
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• v.15 no.1
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• pp.87-91
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• 2014

This paper suggested a web based error manager for societal security service. This is a system that is suitable for detecting, sharing and recovering software error based on multimedia CSCW(Computer Supportes Cooperated Work). With error sharing system, a group cooperating users can share error applications. Our a web based error manager for societal security service enables user to share error objects through interaction awareness. This method has a file sharing, a window copy, a window overlay, or a window sharing. We implemented the web based error manager for societal security service so that the users participated in collaborative work may refer shared error objects as the same view to others.

• Journal of the Korea Society of Computer and Information
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• v.26 no.12
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• pp.159-168
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• 2021

Building Information Modeling (BIM) data is a digitized construction design by worldwide construction design stands rules. Some research are being conducted to utilize blockchain for safe sharing and trade of BIM data, but there is no way to store BIM data directly in the blockchain due to the size of BIM data and technical limitation of the blockchain. In this paper, we propose a method of storing BIM data by combining a distributed file system and a blockchain. We propose two network overlays for storing BIM data, and we also propose generating the Level of Detail (LOD)-based merkle tree for efficient verification of BIM data. In addition, this paper proposes a system design for distributed storage of BIM data by using blockchain besu client and IPFS client. Our system design has a result that the processing speed stably increased despite the increase in data size.

• Journal of Broadcast Engineering
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• v.10 no.4 s.29
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• pp.474-487
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• 2005

T-DMB (Terrestrial-Digital Multimedia Broadcasting) adopted MPEG-4 BIFS (Binary Format for Scene) Core2D scene description profile and graphics profile as the standard of video associated data service. By using BIFS, we can support to overlay objects, i.e. text, stationary image, circle, polygon, etc., on the main display of receiving end according to the properties designated in broadcasting side and to make clickable buttons and website links on desired objects. Therefore, a variety of interactive data services can be served by BIFS. In this paper, we implement real-time video associated data service system far T-DMB. Our developing system places emphasis on real-time data service by user operation and on inter-working and stability with our previously developed video encoder. Our system consists of BIFS Real-time System, Automatic Stream Control System and Receiving Monitoring System. Basic functions of our system are designed to reflect T-DMB programs and characteristics of program production environment as a top priority. Our developed system was used in BIFS trial service via KBS T-DMB, it is supposed to be used in T-DMB main service after improvement process such as intensifying system stability.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.12
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• pp.2179-2187
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• 2008

The P2P technology has been widely used to distribute files efficiently, and its use in streaming is rapidly increasing. P2P streaming has issues about startup-delay, scalability, and real-time playback, however, what affects these factors has not been researched sufficiently. This paper suggests a buffering model for progressive download within mesh-based P2P system, which corresponds to downloading and playing the content at the same time. It is used to analyze PDF(Playback Deadline First), Rarest algorithms which are block-selection strategies of P2P streaming and proposes a mixed selection of them. The mixed block selection strategy dynamically performs different strategies based on whether the blocks to be played are received or not. In consequence, it enhances the QoS of streaming in a single peer point of view, as well as improving block distributions in an overlay network.