• Journal of Digital Contents Society
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• v.13 no.4
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• pp.567-574
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• 2012

In this paper, we propose a buffering scheme to improve the performance by adaptively adjusting the length of the buffering period according to the degree of data duplication among peers that belong to each specific playback period in P2P live streaming systems. To do so, we first assign all the peers into many groups depending on their playback time positions. We then determine the length of their buffering periods according to the number of peers belonging to each group. That is, we increase the length of the buffering periods when much buffered data are duplicated among peers within a group while we decrease it when few buffered data are duplicated. By simulation experiments, we show that our proposed buffering scheme can improve the performance significantly compared to the fixed length buffering scheme that have been employed in the existing mesh-based P2P systems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.1
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• pp.89-99
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• 2017

Many works have attempted to solve the scalability, the availability, and the low-latency problems of peer-to-peer (P2P) live video streaming; yet, the problems still remain. While tree-based systems are vulnerable to churn, the mesh-based systems suffer from high delay and overhead. The DHT-aided chunk-driven overlay (DCO) [1] tried to tackle these problems by using the distributed hash table (DHT), which structures into a mesh-based overlay to efficiently share the video segment. However, DCO fully depends on the capacity of the users' device which is small and unstable, i.e., the users' device may leave and join the network anytime, and the video server's bandwidth can be insufficient when the number of users joining the network suddenly increases. Therefore, cloud assist is introduced to overcome those problems. Cloud assist can be used to enhance the availability, the low-latency, and the scalability of the system. In this paper, the DHT is used to maintain the location of the streaming segments in a distributed manner, and the cloud server is used to assist other peers when the bandwidth which required for sharing the video segment is insufficient. The simulation results show that by using the threshold and cloud assist, the availability and the low-latency of the video segments, and the scalability of the network are greatly improved.

• 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 Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.12B
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• pp.758-766
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• 2007

IStreaming services with a client-server architecture have scalability problem because a server cannot accomodate clients more than its processing capability. This paper introduces a case study for implementing H.264 streaming system based on P2P architecture in order to provide scalable and stable broadcast streaming services over the internet. The prototype system called OmniCast264 consists of the H.264 encoding server, the streaming server, the proxy server, and peer nodes. The proxy server dynamically manages placement of the peer nodes on the P2P network. Omnicast264 has the concepts of distributed streaming loads, real-time playback, error-robustness and modularity. Thus, it can provide large-scale broadcast streaming services. Finally, we have built P2P streaming systems with 12 PCs connected serially or in parallel. The experiment shows that OmniCast264 can provide real-time playback.

• 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.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.3
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• pp.206-211
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• 2014

In this Paper, We proposed the HLS(Http Live Streaming) transmitter which is operated easily and cheap in all networks and client environments compared to the exist video live streaming transmitter. We analyzed the HLS protocol and then implemented for making the HLS transmitter cheaper and portable. After designing the HLS transmitter hardware using the RISC processor of Arm11 core, we ported the Linux Operating System and implemented the HLS protocol using the open source FFmpeg and Segmenter. For the performance evaluation of the developed HLS transmitter, we made the testing environment which is including the notebook, iPhone, and aroid Phone. In this testing environment, we analysed the received video data at the client displayer. As a results of the performance evaluation, we could certify that the proposed HLS transmitter has a higher performance than the Apple company's HLS.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.4
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• pp.326-334
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• 2016

In this paper for developing and implementing the realtime HD level video streaming transmitter which is operated on the multi-platform in all network and client environment compared to the exist video live streaming transmitter. We design the realtime HD level video streaming transmitter supporting the multi-platform using the TMS320DM386 video processor of T.I company and then porting the Linux kernel 2.6.29 and implementing the RTSP(Real Time Streaming Protocol)/RTP(Real Time Transport Protocol), HLS(Http Live Streaming), RTMP(Real Time Messaging Protocol) that can support the multi-platform of video stream protocol of the received equipments (smart phone, tablet PC, notebook etc.). For proving the performance of developed video streaming transmitter, we make the testing environment for testing the performance of streaming transmitter using the notebook, iPad, android Phone, and then analysis the received video in the client displayer. In this paper, we suggest the developed the Realtime HD(High Definition) level Video Streaming transmitter performance data values higher than the exist products.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.1
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• pp.5-23
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• 2011

One inevitable problem in Ad Hoc networks is the limited battery capacity, which explains why portable devices might shut down suddenly when the power of hardware is depleted. Hence, how to decrease the power consumption is an important issue in ad hoc networks. With the development of wireless technology, mobile devices can transmit voices, surf the Internet, download entertaining stuffs, and even support some P2P applications, like sharing real-time streaming. In order to keep the quality stable, the transmission must be continuous and it is thus necessary to select some managers to coordinate all nodes in a P2P community. In addition to assigning jobs to the staffs (children) when needed, these managers (ancestors) are able to reappoint jobs in advance when employees retire. This paper proposed a mechanism called Cluster-based Power Management (CPM) to stabilize the transmissions and increase Time to Live (TTL) of mobile hosts. In our new proposed method, we establish the clusters according to every node's joining order and capability, and adjust their sleep time dynamically through three different mathematical models. Our simulation results reveal that this proposed scheme not only reduces the power consumption efficiently, but also increases the total TTLs evidently.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3B
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• pp.517-525
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• 2010

The IPTV Service provides various interactive services beyond the level of being able to substitute cable TV. The IPTV system is to be decentralized gradually in which one server conducts all tasks. Primarily, deliberation of media needs to be changed into a system in which relayer and peer from the central server is utilized. Secondarily, the way of controling IPTV network need to be decentralized. Unlike the current client-server system, P2P(Peer To Peer), the main technology of decentralized IPTV is able to provide a service by cooperation of each node. Dealing with live streaming IPTV system which is based on the P2P protocol, this paper design the pure P2P IPTV structure and does verify the performance of P2P IPTV structure by realizing real system.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.310-313
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• 2013

BitTorrent는 파일 공유를 위하여 가장 널리 사용되고 있는 P2P (Peer to Peer)프로토콜로서, Mesh-Pull 구조를 채용하여 라이브 스트리밍에 대한 연구가 꾸준히 이루어지고 있다. BitTorrent에서는 Peer Wire Protocol을 사용하여 피어들간에 파일조각들을 교환하게 되는데, 이를 위하여 주기적으로 버퍼맵 정보를 HAVE 메시지를 사용하여 브로드캐스트 하는데, 피어의 수가 증가할수록 이로 인한 시그널링 오버헤드가 크게 증가하는 문제를 갖고 있다. 본 논문에서는 이러한 문제를 극복하고 라이브 스트리밍의 성능을 개선하기 위하여 HAVE 메시지를 선택적으로 전송하는 방법을 제안한다. 실험을 통하여, 제안 방식은 기존의 BitTorrent 기반 Mesh-Pull 구조를 채용하는 라이브 스트리밍 방식과 비교하여 HAVE 메시지의 브로드캐스트로 인한 시그널링 오버헤드를 비약적으로 줄일 수 있음을 보였다.