• The KIPS Transactions:PartA
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• v.11A no.7 s.91
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• pp.511-520
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• 2004

A peer-to-peer model is very useful in solving the server link bottleneck problem of a client-server model. In this work, we discuss the problems of distributing multimedia content over peer-to-peer network. We focus on two problems in peer-to-peer media content distribution systems. The first is the transmission scheduling of the media data for a multi-source streaming session. We present a sophisticated scheduling scheme called fixed-length slotted scheduling, which results in minimum buffering delay. The second problem is on the fast distribution of media content in the peer-to-peer system that is self-growing. We propose a mechanism accelerating the speed at which the system's streaming ca-pacity increases, called FAST.

• Journal of Information Processing Systems
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• v.2 no.1
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• pp.6-12
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• 2006

Peer-to-Peer (P2P) networks are attracting considerable research interest because of their scalability and high performance relative to cost. One of the important services on a P2P network is the streaming service. However, because each node in the P2P network is autonomous, it is difficult to provide a stable streaming service on the network. Therefore, for a stable streaming service on the P2P network, a fault-tolerant scheme must be provided. In this paper, we propose two new node selection schemes, Playback Node First (PNF) and Playback Node first with Prefetching (PNF-P) that can be used for a service migration-based fault-tolerant streaming service. The proposed schemes exploit the fact that the failure probability of a node currently being served is lower than that of a node not being served. Simulation results show that the proposed schemes outperform traditional node selection schemes.

• The Journal of the Korea Contents Association
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• v.10 no.9
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• pp.68-78
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• 2010

As the IP multicast function is very slowly deployed in Internet due to its scalability problem and inter-domain interoperability problem, interest in the P2P(Peer-to-Peer) streaming technologies for the realtime multimedia multicast applications such as IPTV is highly growing. This paper proposes a P2P streaming method for the QoS-sensitive multimedia multicast applications such as highly-interactive personal IPTV and video conferences. The proposed P2P streaming method allows an application to construct a reliable streaming tree in which a proper number of backup peers are placed according to its reliability requirement. The reliable streaming tree reduces the reconnection delay, occurred in the case of a normal and/or abnormal peer leave, so as to minimize the loss of streaming data. In the proposed P2P streaming method, the join delay of a peer called startup delay is also substantially reduced because the bandwidth and end-to-end delay information of every peer kept in a distributed way allows the target peer for a joining peer to be able to be quickly determined. Moreover, the proposed method's peer admission control mechanism based on the bandwidth and end-to-end delay enables the delay-bounded streaming services to be provided for its corresponding applications.

• 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 the Institute of Electronics and Information Engineers
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• v.52 no.1
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• pp.40-47
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• 2015

We propose a method to provide a selective VoD service during live streaming sessions. In the proposed method, each peer joined the live streaming session receives video stream packets with P2P manner and stores the packets to provide a VoD service. To mitigate the overhead of each peer node to store the video stream packets, the proposed scheme categorizes peers into three different groups based on their link types. To increase data gathering speed and reduce the network load, we also proposes the P2P transmission scheme within the same AP network for the peers with Wi-Fi link. To evaluate the performance of the proposed method, we implement computer simulator using NS-3. Simulation results show that the proposed method reduces the overhead about 66% and increases the P2P data gathering speed about 50% compared to the conventional schemes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.11
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• pp.2143-2159
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• 2011

The hybrid architecture of content delivery networks (CDN) and peer-to-peer overlay networks (P2P) is a promising technology enables effective real-time streaming services. It complements the advantages of quality control and reliability in a CDN, and the scalability of a P2P system. With real-time streaming services, however, high connection setup and media delivery latency are becoming the critical issues in deploying the CDN-P2P system. These issues result from biased peer selection without location awareness or content awareness, and can lead to significant service disruption. To reduce service disruption latency, we propose a group-based CDN-P2P hybrid architecture (iCDN-P2P) with a location/content-aware selection of peers. Specifically, a SuperPeer network makes a location-aware peer selection by employing a content addressable network (CAN) to distribute channel information. It also manages peers with content awareness, forming a group of peers with the same channel as the sub-overlay. Through a performance evaluation, we show that the proposed architecture outperforms the original CDN-P2P hybrid architecture in terms of connection setup delay and media delivery time.

• The KIPS Transactions:PartB
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• v.17B no.3
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• pp.189-196
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• 2010

Peer-to-Peer (P2P) has attracted attention as an alternative way to enable streaming videos on the Internet. Although P2P systems depend on bandwidth contribution from peers, peers are likely to refuse to contribute their bandwidth. In this paper, we proposed a P2P streaming system that encourages peers to contribute their upstream bandwidth by maintaining fairness among peers and providing different video quality between cooperative peers and selfish peers with a manageable way. Our proposed system determines if peers are cooperative or selfish by a rating mechanism based on their contributed upstream bandwidth, and offers a high quality video to cooperative peers as an incentive. Also we propose a tree reconstruction algorithm to make the system work effectively. Through simulation, we show that the tree reconstruction algorithm works effectively, and our incentive mechanism allocates more downstream bandwidth to cooperative peers and punished selfish peers with low quality video.

• Journal of the Korea Society of Computer and Information
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• v.15 no.3
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• pp.81-89
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• 2010

The research on peer-to-peer streaming schemes has largely focused on tree-push and mesh-pull structures. However, the tree-push structure has a defect that the tree restructuring time is long, and the mesh-pull structure has long startup delay and lag time from source servers. In this paper, we propose a new peer-to-peer live streaming scheme based on a push-mesh structure that takes advantages of tree-push and mesh-pull structure simultaneously. This structure basically provides the mesh-pull mechanism for data transmission and utilizes peers with high network upload capacity. It also supports the push mechanism along with paths from a source server, super peers, and selected general peers. By NS-2 simulation experiments, we finally show that our proposed scheme can achieve shorter startup delay than the mesh-pull structure, similar lag time to tree-push structure and best playback continuity among the three schemes.

• Journal of the Korea Society of Computer and Information
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• v.17 no.5
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• pp.49-57
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• 2012

In P2P streaming management, peer's churning and finding efficient topology architecture optimization algorithm that reduces streaming delay is important. This paper studies a topology optimization algorithm based on the P2P streaming using peer's link information. The proposed algorithm is based on the estimation of peer's upload bandwidth using peer's link information on mesh-network. The existing algorithm that uses the information of connected links is efficient to reduce message overload in the point of resource management. But it has a risk of making unreliable topology not considering upload bandwidth. And when some network error occurs in a server-closer-peer, it may make the topology worse. In this paper we propose an algorithm that makes up for the weak point of the existing algorithm. We compare the existing algorithm with the proposed algorithm using test data and analyze each simulation result.

• Journal of Digital Contents Society
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• v.14 no.1
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• pp.25-33
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• 2013

P2P(Peer-to-Peer) architecture can reduce the network bandwidth and resource on the server since peers exchange data chunks with each other, while server-client architecture causes a lot of traffic on the server. Peers receive a data more reliably when the number of participating peer increases. Currently, P2P traffic has accounted for about 65% of the world's Internet traffic and diverse P2P streaming services have launched combining to video streaming technology. However, the requirements and data chunk delivery algorithms for mobile P2P streaming service should be investigated, since the existing P2P technologies have been developed and designed for the wired network. In particular, the bandwidth fluctuation caused by user mobility, wireless packet collisions, and packet losses brings about different problems on the mobile P2P streaming service compared to existing P2P streaming service. In this paper, we analyzed the problem of mobile P2P streaming services in the 802.11n wireless LAN environment through experiments.