• The KIPS Transactions:PartA
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• v.13A no.7 s.104
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• pp.623-632
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• 2006

We propose a peer-to-peer search scheme in which super peers with high rapacity constitute a ring by themselves and all peers utilize the ring for their query and publishing keys. In a dynamic peer-to-peer environment, the size of the super peer ring changes adaptively according to the changes of the system, but more powerful peers are continuously promoted to super peers. By simulations, we show that our proposed search scheme improves the query success rate of Gnutella+1hop replication search method, and maintains shorter query delay than JXTA as a static ring.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1B
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• pp.73-85
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• 2004

SIn this paper, we introduce our experience for designing and implementing new concept of a global XML-based Peer-to-Peer (P2P) engine to support various P2P applications, and interconnection among PC, Web and mobile computing environments. The proposed P2P engine can support to heterogeneous data exchanges and web interconnection by facilitating with the text-base XML while message exchange are necessary. It is also to provide multi-level security functions as well as to apply different types of security algorithms. The system consist of four modules; a message dispatcher to scheduling and filtering the message, a SecureNet to providing security services and data transmission, a Discovery Manager to constructing peer-to-peer networking, and a Repository Manager to processing data management including XML documents. As a feasibility test, we implement various P2P services such as chatting as a communication service, white-board as an authoring tool set during collaborative working, and a file system as a file sharing service. We also compared the proposed system to a Gnutella in order to measure performance of the systems.

• Journal of KIISE:Information Networking
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• v.35 no.4
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• pp.251-267
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• 2008

In this paper, we present a distributed topology control algorithm for constructing an optimized topology having a minimal search-time in unstructured peer-to-peer network. According to the proposed algorithm, each node selects the best nodes having higher hit-ratio than other nodes as many as the number being exponentially proportional to the hit-ratio of the node itself, and then it connects to them. The ensemble behavior of the proposed algorithm is very similar to the recrystrallizing phenomenon that is observed in nature. There is a partial order relationship among the hit-ratios of most nodes of constructed topology. Therefore once query message visits a node, it has a higher hit-ratio than the node that was visited last by the message. The query message even sent from freeloader can escape to the node having high hit-ratio by one hop forwarding, and it never revisits any freeloader again. Thus the search can be completed within a limited search time. We also propose the Chain-reactive search scheme using the constructed topology. Such a controlled multicasting reduces the query messages by 43 percent compared to that of the naive Gnutella using broadcasting, while it saves the search time by 94 percent. The search success rate of the proposed scheme is 99 percent.