• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.765-768
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• 2007

P2P Video-on-Demand (VoD) is becoming a popular service in the Internet. The first deployments are already in place, and millions of customers worldwide are already using this new medium. But its success is still quite limited and technically, these researches have been deployed in a rush, mostly based on practicality and instability. This paper studies the advantages and potential problems of VoD in peer-to-peer (P2P) network, we propose a system which uses a distributed VoD streaming scheme over P2P network to support media streaming.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.489-492
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• 2007

본 논문에서는 P2P 네트워크 상에 분산되어 있는 파일들을 수집하고 피어의 신뢰도가 낮은 접속에도 끊김 없는 스트리밍 서비스를 제공하기위해 Sequential Download System(SDS)을 제안하였다. SDS는 Download Manager를 이용하여 여러 피어로부터 파일을 수신하고, 파일 수신 시에 피어의 갑작스런 이탈에 대처하며 스트리밍 시 발생하는 버퍼링 시간을 최소화하여 안정된 스트리밍을 제공하게 된다. 또한 Memory map을 이용하여 다른 피어의 요청에도 대처할 수 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1732-1750
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• 2016

Recently, Peer-to-Peer (P2P) live streaming assisted by the cloud computing has attracted considerable attention to improve the reliability of the P2P such as the resilience to peer churn and the shortage of upload capacity. The cost of cloud-assistance is comprised of the number of requests issued to the cloud and the amount of data fetched from the cloud. In this paper, we propose three techniques to reduce the cost of such a cloud-assistance.More concretely, in the proposed method, 1) each peer which lost its parent in the overlay can find a new parent by referring to the information registered in the cloud, 2) several peers which proactively fetch chunks from the cloud are dynamically invested, and 3) the number of requests issued to the cloud is reduced by allowing peers to fetch a collection of chunks using a single request. The performance of the proposed method is evaluated by simulation. The simulation results indicate that it reduces the cost of conventional scheme by 46% while guaranteeing the quality of live streaming service.

• Journal of Broadcast Engineering
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• v.24 no.2
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• pp.251-263
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• 2019

Recently the huge demand for Internet media streaming has dramatically increased the cost of the CDN (Content Delivery Network) and the need for a means to reduce it is increasing day by day. In this situation, a P2P-assisted DASH technology has recently emerged, which uses P2P (Peer-to-Peer) communications based on WebRTC (Web Real-Time Communication) standards to reduce the CDN cost. This paper proposes an algorithm that can significantly improve CDN cost savings in this technology by selecting peers based on the transport history. Also we implemented this algorithm in an experimental system and, after setting experimental conditions that emulate the actual mobile network environment, we measured the performance of the experimental system. As a result, we demonstrated that the proposed algorithm can achieve higher CDN cost savings compared to the conventional algorithm where peers are selected at random.

• Journal of KIISE:Information Networking
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• v.36 no.6
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• pp.481-491
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• 2009

In this paper, we proposed a hybrid P2P overlay structure for live media streaming. The proposed structure consists of the mesh overlay organized by peers according to the geographical proximity and similar bandwidth range and the tree overlay formed by the peers for which the stability of participation is approved. The proposed scheme enhances the robustness of tree overlay and the long delay of mesh overlay by intelligently combining the utilization of the tree overlay and the mesh overlay. Furthermore, the peers with a large up-link bandwidth are located near to the media source peer. Therefore, it reduces the height of tree, and as a result, the stream transmission delay. Through simulation, we evaluated the performance of the proposed scheme in terms of scalability and quality of services.

• The KIPS Transactions:PartA
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• v.13A no.2 s.99
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• pp.147-156
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• 2006

Recently, streaming service accounts for large part of internet traffic and it is becoming the most popular service. Because of P2P's scalability, P2P-based streaming system is proposed. There are frequent leave and join of a node. To overcome the group dynamics, Multiple Multicast Trees Methods were suggested. However, since they did not consider discrepancy in peers' capacity, it may cause the trees to be long and unstable. So we suggest Resilient Capacity-Aware Multicast Tree construction scheme (R-CAT) that promotes superior peer to upper position in the tree and construct more stable and short multicast trees. By simulation we can show that R-CAT cost more overhead packets for tree joining process, but it reduce the end-to-end delay of the resulting tree and the number of packets lost during the node joining and leaving processes much more than SplitStream.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.312-316
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• 2007

정보통신 기술의 전으로 디지털 콘텐츠분야는 혐의의 문화산업에서 벗어나 범 산업에 공통되는 요소로써 자리매김하고 있다. 디지털 콘텐츠의 급속한 양적 팽창은 콘텐츠의 저작권 보호 문제와 직접적인 충돌을 야기하고 있다. 특히, 저장된 MP3 음악 파일 재생하는 MP3 플레이어가 확산되면서 MP3 음악 파일의 무단 복제로 인한 저작권 침해 문제는 매우 심각하다. 본 논문에서는 이러한 문제를 해결하고 유비쿼터스 환경에 적합한 응용 기기로써 실시간 멀티미디어 재생기, SMP(Streaming Multimedia Player)를 설계한다. SMP는 WiBro 망을 통해 스트리밍 방식으로 음악을 전송받아 재생하는 휴대용 MP3 플레이어로써 저렴한 월정액의 저작권 및 통신요금으로 언제 어디서나 원하는 음악을 서비스 받을 수 있는 유비쿼터스 단말이다. 본 논문에서는 SMP 단말을 설계하고 WiBro 망과 P2P 통신을 이용한 서비스 연결 방식과 콘텐츠 제공 방식을 제안하고 분석한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.69-76
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• 2014

In this paper, we propose a buffering scheme to improve the performance in P2P live streaming systems by adjusting the ratio of caching and prefetching portion of each peer. To this end, we assign all the peers into many groups depending on their playback periods. We then determine the ratio of caching and prefetching portion in each peer depending on its playback time position relative to those of other peers within the same group. In other words, as the playback position of a peer gets later, we increase the ratio of its caching portion. On the contrary, as the playback position of a peer gets eariler, we increase the ratio of its prefetching portion. This can significantly increase the degree of data duplication among peers that belong to each specific group. By simulation experiments, we show that our proposed an integrated prefetching/caching scheme can improve the performance considerably in terms of jitter ratio, initial playback delay and shared buffermap ratio when compared to the existing fixed portion buffering scheme.

• 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.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.33-42
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• 2013

In the early stage of P2P, the technology was limited to narrow usage of file sharing, but currently, P2P technology has become essential to maximize the efficiency between associated technologies without additional deployment of high costly infrastructure and also the burden of the server. Especially, P2P media streaming service is a highly attractive service to mobile users. which requires a higher quality in the mobile environment in accordance with the development of technology of wired network as well as better mobile terminals. However, P2P technology should consider the trade-off between 'peer selfishness' and QoE for providing fairness. The P2P system also try to maximize the resource utilization through an incentive mechanism for service differentiation and encourage peers to contribute continuously for improving the overall system performance. In this paper, we propose an point-based incentive mechanism based on peer's contribution level and energy availability for service differentiation. We also introduce that the proposed mechanism efficiently enhances the system performance as the peer with incentive using contribution and energy obtains more effective resource distribution.