• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.932-935
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• 2007

모바일 기기 사용이 급증함에 따라 모바일환경에서 이루어지는 P2P방식 연구가 활발히 진행되고 있다. 본 논문에서는 기존의 모바일환경에서의 P2P방식이 지닌 peer들 사이의 multi-broadcasting 방식의 문제점을 보완하고, 새로운 routing table을 구축하기 위해 peer들을 2개의 계층으로 구분하였다. 즉, peer들을 super peer들과 각 super peer에 의해 관리되는 sub peer들로 구분하였다. 파일의 탐색과 전송은 super peer들이 관리하므로, 기존의 불필요한 multi-broadcasting 방식을 피할 수 있다. 본 논문에서는 분산 네트워크를 위한 peer의 계층화 작업을 설계하였다. MIS(Maximal Independent Set)알고리즘을 이용하여 peer들의 계층화 작업을 외부의 도움 없이 peer들간의 통신으로 할 수 있게 만들었다. 이처럼 peer들을 super peer와 sub peer로 구분하면 불필요한 broadcasting을 피할 수 있어 시스템 성능이 향상되며, 이를 실험을 통하여 증명하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.3
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• pp.528-534
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• 2007

As XML is becoming a standard for representation and exchange of abundant information on the Web, solutions for a secure and selective dissemination of XML data, known as SDI, are strongly demanded. Such trends are more outstanding especially in distributed heterogeneous environment such as Peer-to-Peer. Although many approaches have been proposed to provide secure and efficient SDI mechanisms, almost previous approaches have focused only on filtering with user profile and they adopt center-oriented administration approaches. It is therefore difficult to adapt them directly to the distributed Peer-to-Peer environments characterized by dynamic participation. In this paper, we develop a novel dissemination method, which makesuse of authorization policy and secret sharing scheme. It provides more secure, scalable means for XML dissemination on Peer-to-Peer networks.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.06a
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• pp.481-487
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• 2001

본 논문은 현재까지 제시되어진 peer to peer network model들을 정리하고 대표적인 peer to peer network model에 지문인식을 적용하여 개인에 대한 신원 인증 절차를 수행함으로써 보안에 대한 새로운 해결책을 제안하였다. 기존의 peer to peer network model은 개인 대 개인간의 효율적인 network검색 기능과 분산 computing 환경을 제공하지만 보안에 관해서는 아직까지도 많은 연구가 필요하다. 본 연구에서는 기존의 peer to peer network model들에 지문인식을 사용한 새로운 보안 model을 설계하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04a
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• pp.275-278
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• 2001

인터넷의 활용이 급속도로 확산되어지고 사용환경도 점점 고급화가 되어가고 있다. 분산환경에는 네트웍에 연결된 각 Peer 들의 유휴자원을 이용하여 대규모의 데이터를 처리하기 위한 연구와 기존의 클라이언트-서버 환경에서의 부하를 각 Peer들에게 분산시키는 연구가 활발하게 진행되고 있다. 이 연구에서는 서버의 지원이 없는 순수 Peer-to-Peer 환경에서 현재의 Peer 들의 네트웍 구성을 살펴보고 효율적으로 중복된 메시지를 제어하기 위한 Ring-based 클러스터를 통한 네트웍 구성 환경과 클러스터간의 메시지 전파와 대역폭에 따른 클러스터 기법을 제안한다.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2002.05a
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• pp.383-390
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• 2002

본 논문에서는 Peer-to-Peer 환경에서의 협동적 필터링의 필요성에 대해 논의하고, 이를 위한 P2P 컴퓨팅의 구조 설계, Peer Clustering기법, Peer간 메시지의 종류, 그리고 이를 구현한 시스템에 대하여 설명한다.

• Journal of Advanced Navigation Technology
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• v.15 no.4
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• pp.632-639
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• 2011

Searching distributed resource efficiently is very important in distributed computing, cloud computing environment. Distributed resource searching may have system overheads and take much time in proportion to the searching number, because distributed resource searching has to circuit many peers for searching information. The open-source community project JXTA defines an open set of standard protocols for ad hoc, pervasive, peer-to-peer computing as a common platform for developing a wide variety of decentralized network applications. In this paper, we proposed peer search algorithm based on JXTA-Sim. original JXTA peer searching algorithm selected a loosely-consistent DHT. Our Lookup algorithm decreases message number of WALK_LOOKUP and reduce the network system overload, and we make a result of same performance both original algorithm and our proposed algorithm.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.401-404
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• 2002

최근 모자이크의 시대 이후 인터넷의 폭발적인 발달로 인해 Client-Sever의 방식의 네트웍 서비스 방식 뿐만 아니라 P2P(Peer to Peer) 등 분산 서비스 환경이 각광을 받고 있다. 사용자의 직접적인 자료의 공유를 위해서는 Peer to Peer 환경을 설정하여 분산되어진 자료의 효과적인 관리를 위한 통신의 주체가 되는 각각의 에이젼트들 간의 통신과 Sever와 Agent의 통신에 있어 악의적인 침입에 의한 정보누출이 문제가 되고 있다. 본 논문에서는 이러한 문제의 해결방안으로 P2P 환경에 적합한 PKI(공개키 기반구조)를 기반을 이용하여 보안 메커니즘을 설계하였다.

• Spatial Information Research
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• v.18 no.3
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• pp.53-62
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• 2010

Recent development in wireless communication technology, like GPS, and mobile equipments, like PDA and cellular phone, make location-based services (LBSs) popular. However, because, users continuously request a query to a server in the LBSs by using their exact locations, privacy information could be in danger. Therefore, a mechanism for users' privacy protection is required for the safe and comfortable use of LBSs by mobile users. For this, we, in this paper, propose a grid-based cloaking area creation scheme supporting continuous LBSs in peer-to-peer environment. The proposed scheme creates a cloaking area by using Chord protocol, so as to support the continuous LBSs in peer-to-peer environment. Finally, we show from a performance analysis that our cloaking scheme outperforms the existing cloaking schemes, in terms of service time.

• Journal of KIISE:Information Networking
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• v.32 no.6
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• pp.705-715
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• 2005

A peer-to-peer web caching has been studied recently as it can reduce the traffic converged on the server side and can support the traditional web caching model. Although the peer-to-peer web caching has the merit of having additional cache space from the local caches of peers without additional infrastructure, several constraints such as dynamic participation and local caching strategy caused by the autonomy of peers in peer-to-peer networks nay limit the performance of the peer-to-peer web caching. To overcome these limitations, we propose an efficient directory-based peer-to-peer web caching system under dynamic participation of peers. In the proposed caching system, we present new peer selection and replica management schemes by introducing the concept of the object lifetime in P2P networks. We evaluate the effectiveness of the proposed system through trace-driven simulations with a web log dataset. Simulation results show that the proposed system has higher accuracy and fewer redirection failures than the conventional directory-based P2P web caching system in feasible peer-to-peer networks.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.3
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• pp.286-290
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• 2008

As the number of mobile device users increases, many researches on peer-to-peer(P2P) systems in mobile environments have been carried out. In this paper, we propose a couple of double-layered P2P file sharing systems to overcome the 'flooding' problem in previous mobile P2P systems. We classify peers into two groups, super peers and sub-peers to establish new routing tables. A super peer manages its sub-peers in the systems. The first proposed system partitions the service area into small cells, each of which is a square. Each super peer is located near the center of the square. The second system selects super peers which have the largest number of adjacent peers. As file transmission and file searches are managed mainly by super peers, unnecessary multi-broadcasting could be avoided. The experimental results show that the proposed systems outperform a typical file sharing system in terms of the amount of message traffic with about $1.2{\sim}1.6$ times improvement on the average.