A Measurement Study of the Structured Overlay Network in P2P File-Sharing Systems

The architecture of P2P file-sharing applications has been developing to meet the needs of large scale demands. The structured overlay network, also known as DHT, has been used in these applications to improve the scalability, and robustness of the system, and to make it free from single-point failure. We believe that the measurement study of the overlay network used in the real file-sharing P2P systems can provide guidance for the designing of such systems, and improve the performance of the system. In this paper, we perform the measurement in two different aspects. First, a modified client is designed to provide view to the overlay network from a single-user vision. Second, the instances of crawler programs deployed in many nodes managed to crawl the user information of the overlay network as much as possible. We also find a vulnerability in the overlay network, combined with the character of the DNS service, a more serious DDoS attack can be launched

Heuristics for Cultural Algorithm Knowledge Driven Search in Dynamic Social Systems

Population evolution algorithms such as Cultural Algorithms (CA) enable a global repository known as the belief space consisting of common cultural traits to influence the population space. Two important aspects of CA are the knowledge and its propagation. The population use social networks for communication. Knowledge representation is generally dependent on the application at hand. In this thesis the role of CA belief space knowledge in application neutral simulation is explored. A standard benchmark function is used to study the performance of evolutionary algorithms. The function captures the characteristics of a neutral world in dynamic settings. A multi-agent simulation was designed where autonomous agents are able to communicate, acquire and exploit various knowledge types including topographic, domain, historical and situational. While all these strategies showed improvements when searching for the global maximum, we found that domain based topographic exploitation strategies of the landscape were the more efficient

Measurement study and application of social network in the Maze P2P file-sharing system

Search in P2P networks is an open problem, and most of P2P networks reflect social relationships. By studying and leveraging social networks of P2P systems, search effect can be significantly improved. In this paper, we report results of analyzing and measuring of social networks in Maze, a large-scale peer-to-peer file sharing system. Given the definition and measurement of social relationship, friend network and download network are analyzed based on Maze's daily log. On both networks, the construction, structure, and 'small-world' property are illustrated. And it is proven that both networks reflect social relationships. Leveraging the social networks and EigenTrust algorithm, a search approach EigenForwarding(k,t) is presented. Comparing with flooding and random forwarding, the approach is shown that can gain a good hit rate with small messaging cost and search path length due to sufficient exploiting of sociality. ? 2006 ACM.EI