• Proceedings of the IEEK Conference
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• summer
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• pp.159-164
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• 2004

This paper aims towards designing and implementation of a new adaptive Peer to Peer (P2P) network that cluster itself on the basis of semantic proximity. We also developed an algorithm to classify the nodes to form the semantic groups and to direct the queries to appropriate groups without any human intervention. This is done using Bloom filters to summarise keywords of the documents shared by a peer. The queries are directed towards the appropriate clusters instead of flooding them. The proposed topology supports a system for maintaining a global, omnipresent trust value for each peer in an efficient manner both in terms of decision time and network load.

• Proceedings of the KIEE Conference
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• 2004.05a
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• pp.62-64
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• 2004

P2P Systems have grown dramatically in recent years. Now many P2P systems have developed and been confronted by P2P technical challenges. We should consider how to efficiently locate desired resources. In this paper we integrated the existing pure P2P and hybrid P2P model. We try to keep roles of super peer in hybrid and concurrently use pure P2P model for searching resource. In order to improve the existing search mechanism, we present contents-based classification mechanism. Proposed system have the following features. This can forward only query to best peer using RI. Second, it is self-organization. A peer can reconfigure network that it can communicate directly with based on best peer. Third, peers can cluster each other through contents-based classification.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.10 no.4
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• pp.121-127
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• 2011

Many peer-to-peer (p2p) systems have been studied in distributed, ubiquitous computing environments. Distributed hash table (DHT)-based p2p systems can improve load-balancing even though locality utilization and user mobility are not guaranteed. We propose a mobile locality-based hierarchical p2p overlay network (MLH-Net) to address locality problems without any other services. MLH-Net utilizes mobility features in a mobile environment. MLH-Net is constructed as two layers, an upper layer formed with super-nodes and a lower layer formed with normal-nodes. Because super-nodes can share advertisements, we can guarantee physical locality utilization between a requestor and a target during any discovery process. To overcome a node failure, we propose a simple recovery mechanism. The simulation results demonstrate that MLH-Net can decrease discovery routing hops by 15% compared with JXTA and 66% compared with Chord.

• 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.

• 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.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06d
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• pp.163-165
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• 2006

비구조적인 피어-투-피어 시스템은 구조적 피어-투-피어 시스템에 비해 동적인 상황에 적합하지만 메시지가 여러 다른 피어를 이동하면서 검색하기 때문에 검색 시간이 길고 검색의 성공률이 낮다. 이러한 문제를 해결하기 위해 우수 피어를 사용한 계층적 피어-투-피어 시스템이 연구 되었다. 효율적인 계층적 피어-투-피어 시스템을 구성하기 위해서는 어떤 피어가 얼마나 많이 우수 피어로 선택되어야 하는지가 중요하다. 본 논문에서는 기존에 연구된 자기 조직적 링 구조 기법을 기반으로 우수 피어의 비율을 환경에 적응하게 하는 시스템을 제안한다. 환경에 적합한 비율 조절을 위해 효율적으로 최적 또는 최적에 가까운 해를 찾는 것으로 알려진 입자 군집 최적화(PSO : Particle Swarm Optimization)기법을 사용하였고 성능 평가 결과 PSO를 적용한 시스템에서 성능 향상을 볼 수 있었다.

• Journal of information and communication convergence engineering
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• v.9 no.4
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• pp.396-400
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• 2011

P2P(peer to Peer) network is a distributed network architecture composed of participants that make a portion of their resources directly available to other network participants, without the need for a central server. Currently, convergence network industry using wired and mobile are grows rapidly. So P2P protocols will be used between mobile and wired network. But current P2P protocols are focused on the wired networks only and there are no simulators for performance analysis of mobile P2P. In this paper, we design a P2P simulation system for performance analysis of P2P protocols in mobile, wired and convergence networks. It is constructed by a well-known mobile network simulator and wired based P2P protocol simulator. Finally we have implemented a smart TV test-bed using our P2P test-bed for convergence networks.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.754-757
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• 2009

본 논문에서는 휴대 단말을 소지한 사용자가 재난 발생시 구조자로부터 접근이 용이하지 않을 때, 구조자 대신 인명을 찾는 다수의 로봇이 효율적인 탐색을 할 수 있도록 target space(재난 발생 영역)를 각 노드의 통신 범위를 기반하여 셀 단위로 분할한다. 각 노드가 동일한 방향으로 탐색하는 비효율성을 개선하기 위해 셀에서 방향을 설정해 각 노드가 탐색하며, 여러 셀을 묶어 노드들의 탐색범위를 분할하는 방법을 제안한다. 탐색에 참여하는 노드들의 협동 방법으로는 모바일 환경에서의 효율적인 Peer-to-Peer 시스템으로 제안된 double-layered topology 를 기반으로 노드들을 구성하여 super peer 를 통해 맵 정보, 장애물정보, 위험지역 정보를 구조자의 요청에 따라 응답하여 인명을 구조하는 방법을 제안한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.4
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• pp.103-109
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• 2008

Many Internet application provide the PKI(public key infrastructure)-based service to provide authentication and message integrity. Several researchers proposed PKI-based p2p network framework. However, in the real world, the use of PKI is not suitable for peer to peer network, because the peer-to-peer network is an open and dynamic network. Moreover, currently there is no nation-to-nation interoperable certificate. In this paper, we designed reliable p2p file sharing application without public key infrastructure. To do this we propose reliable public key distribution mechanism to distribute public key safely without PKI infrastructure for two-tier super-peer architecture. In our system, each peer generates and distributes its public/private key pairs, and the public key is securely distributed without PKI. The proposed mechanism is safe against MITM attack. This mechanism can be applied various P2P applications such as file sharing, IPTV, distributed resource sharing and so on

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.826-829
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• 2008

모바일 환경에서는 모바일 기기의 제한된 에너지를 효율적으로 사용하는 것이 요구된다. 특히 모바일 Peer-to-Peer(P2P) 시스템에서 모바일 기기가 피어로서 저장된 에너지를 모두 소모하면 더 이상파일 탐색 등과 같은 작업에 참여할 수 없게 된다. 또한 에너지가 없는 피어가 증가하게 되면 파일탐색 실패율이 증가하게 되고, 결국 파일탐색이 불가능하게 된다. 슈퍼피어(super peer)를 기반으로 한 계층적 P2P 시스템은 기존 단일 계층 P2P 시스템보다 더 적은 양의 메시지로 파일탐색을 가능하게 해준다. 하지만 하나의 슈퍼피어가 관리하는 서브피어(sub-peer)가 많을 경우, 서브피어의 관리 비용과 파일 탐색 요청의 증가로 슈퍼피어의 에너지 소모 비율이 크게 증가하게 되며, 이로 인해 네트워크 참여 시간이 줄어들게 된다. 이는 전체 네트워크 유지시간 감소에 영향을 미친다. 본 논문은 무선 통신 기반의 모바일 환경에서 슈퍼피어를 기반으로 한 계층적 P2P 시스템을 기반으로, 슈퍼피어가 관리하는 서브피어들의 수를 제한하고, 만약 일정한 수를 초과하였을 경우, 초과한 슈퍼피어의 서브피어들 중에서 새로운 슈퍼피어를 선정하고, 기존 슈퍼피어로부터 일부 서브피어들을 분배하여 관리하게 하는 시스템을 제안하였다. 실험을 통해 성능을 평가 하였으며, 실험 결과 파일 탐색 요청을 위한 네트워크 유지시간이 더 오래 지속됨을 확인하였다.