【作者】 邵世伟；

【导师】 吴家皋；

【作者基本信息】 南京邮电大学 ， 计算机应用技术， 2012， 硕士

【摘要】 计算机技术的迅速发展给地理信息系统带来了巨大的变化,随着空间数据量和计算复杂性的增加,地理信息系统所采用的集中式模式面临着诸多挑战。P2P技术作为一种新的分布式计算模式,为分布式地理信息共享提供了新的技术手段。该技术能够有效利用网络中的边缘资源,把网络中参与者的网络资源整合起来,利用参与者的存储空间和计算能力来保存海量数据和处理各种请求,从而提高分布式矢量地理数据的组织效率与索引性能。本文对已有的混合结构P2P空间索引网络进行分析总结,提出一种基于混合结构索引网络的优化机制。该优化机制是基于索引树结构的一种新的组策略思想,将具有相同空间数据语义的客户端加入到同一组中,由组中成员节点共同负担查询请求任务,并且由组中的当前索引节点负责本组成员节点的管理。本文提出的组策略主要包括节点加入机制、传输节点选取机制、当前索引节点替换与备份机制和组管理机制。组策略可以加强原索引网络的拓扑结构,提高整个网络的查询性能和稳定性。经PeerSim的仿真模拟,验证了该优化机制是可行的。最后,本文在JXTA平台上实现了基于P2P的空间矢量数据索引网络动态优化机制的原型系统。测试结果表明,有组策略的索引网络能够有效利用客户端的网络资源,提高查询性能。更多还原

【Abstract】 The rapid development of computer technology has brought great changes in geographical information system. With the increasing of spatial data size and computational complexity, geographical information system which uses the centralized model is facing many challenges. P2P technology as a new distributed computing model provides a new way for geographical information sharing. The technology can effectively make use of the edge of network resources and can integrate the network resources of participants. It can improve the efficiency of distributed vector geographical data organization and the performance of spatial indexing by utilizing the storage space and computing capabilities of participants to save amounts of data and process kinds of requests.In this thesis, an optimization mechanism is proposed based on analyzing and summarizing the existing hybrid P2P spatial indexing network. The optimization mechanism is a new idea of group strategy based on the structure of index tree. In this idea, peers with the same spatial data semantics are joined in the same group in which the burden of query is shared by group members together. The current index node in the group is responsible for the management of group members. The group strategy contains node join, the transmission node selection, the current index node replacement and backup and group management mechanism. It can enhance the topology of the original indexing network and improve the query performance and stability of the overall network by using group strategy. The simulation results used PeerSim verify the feasibility of the optimization mechanism. In addition, a P2P based prototype system of dynamic optimization mechanism for spatial vector data indexing network is implemented, which is based on JXTA platform. The experimental results indicate that the indexing network with group strategy can effectively make use of clients’network resources and improve the query performance.更多还原