【作者】 杨莹；

【导师】 肖文俊；

【作者基本信息】 华南理工大学 ， 计算机软件与理论， 2011， 硕士

【摘要】 对等网络(Peer-to-Peer,简称P2P)是一种新兴的复杂网络。近年来,随着Internet的广泛使用以及接入Internet的计算机系统性能的持续增长,对等网络的计算模式得到快速发展,逐渐成为Internet的重要应用之一。对等网络改变了服务器端与客户端的明显区别,提高了网络中资源、带宽的利用率,增强了网络的可扩展性、可靠性。人们发现即使每个用户提供少量文件,整个用户群所共享的文件数也是非常的庞大的。要想充分地利用网络中的这些资源,前提是能够有效尽可能快地搜索到资源。与传统的服务器端系统不同,P2P系统具有规模巨大和动态性强等特点,这些特点给P2P资源搜索技术提出了巨大的要求。P2P搜索算法主要分为结构化搜索算法和无结构化搜索算法两大类。前者虽然平均查询跳数较低,但存在系统难以维护、不支持复杂查询等缺点;而后者简单灵活且鲁棒性好,但其平均查询跳数大、系统可扩展性差。本文对P2P网络中的各种搜索路由算法进行了深入的研究和探讨。结合P2P网络自身符合复杂网络的特点,首先研究了针对P2P网络生成的特点,通过改进BA模型,引入了一种局域吸引度择优扩展模型(PASEN)。先从理论上对模型进行了分析,再通过仿真实验,计算生成网络的度分布以及小世界特征,对实验结果进行分析。接着针对P2P网络中的超级节点的结构和目前最大度搜索算法中的缺点,提出了最大度节点优先渐进式搜索算法(MDFI),在之前提出的局域吸引度择优扩展模型上进行验证分析。通过与Random Walk算法和最大度搜索算法进行对比,从实验结果以及分析可得出,新搜索算法在查询成功率、平均查询包数和平均查询跳数总体上有了明显的改进。最后,对本文的研究课题进行了总结和展望。更多还原

【Abstract】 . Peer-to-Peer (P2P) network is a new kind of complex network. In recent years, with the widespread use of Internet and the continuously improved performance of computer system connected to the Internet, the rapid development of peer-to-peer computing pattern gradually makes it become one of the most important Internet applications. P2P networks ignore obvious difference between server and client, improved the utilization of resources and bandwidth; enhanced network scalability, reliability. It is found that even if each individual provides only a few files, enormous file can be shared by the whole group of users.In order to use these abundant resources in the network, the premise is to find them effectively. Unlike other traditional systems, P2P systems demonstrate some special characteristics, such as large-scale and dynamic, which have brought great challenge of resource searching technique in the networks. There are two kinds of P2P search algorithms, structured search algorithms and unstructured search algorithms. Although structured search algorithms can guarantee small average query hops, there are shortcomings such as difficult maintainability and nonsupport for complex search in these systems. On the other hand, unstructured search algorithms are simple, flexible and very robust, but their average query hops in much larger, and their scalability is much unfavorable.Searching algorithms in P2P networks are researched and discussed in depth. Based on the characteristics of complex networks, first study how the P2P networks generated. We introduce a model that is called PASEN (the Model of partial attraction to select excellence node). First, we analyze the model in theory. Then we take the simulation to calculate the degree distribution of generated and small-world, and analyze the result.Based on the super-node in P2P network and the disadvantage of max degree algorithm, we provided a new unstructured searching algorithm: the maximum degree of nodes first and incremental searching algorithm (MDFI), and put to the proof on the PASEN model. Through the experimental result and analysis we can know that, the new search algorithm, compared with random walk algorithm and max degree algorithm, can be concluded that query success rate, average query packets and average query hops in general have been significantly improved. Finally, summarization and prospect on the subject of this paper are given.更多还原