一种基于GridGIS的空间负载平衡算法  

A Load Balancing Algorithm for Spatial Data in GridGIS

作　　者：赵晓晖[1] 方裕[2] 赵家敏[1] 马艳[1] 

机构地区：[1]国核电力规划设计研究院,北京100094 [2]北京大学遥感与地理信息系统研究所,北京100871

出　　处：《地理与地理信息科学》2011年第4期36-40,共5页Geography and Geo-Information Science

摘　　要：空间数据的广泛应用需要高效的架构来管理,以增加空间数据的可用性。网格地理信息系统(GridGIS)支持快速的空间数据检索,允许用户在任何地方随时透明地访问数据,容易引起空间负载失衡。该文提出一种基于GridGIS的空间负载平衡算法——TLB-Chord,采用动态负载平衡思想,使用基于Chord算法的树结构,实现了一个空间负载平衡模拟系统,展示了TLB-Chord在GridGIS中更加适用于空间数据。The wide application of spatial data needs an efficient framework to manage them and increase the availability of spatial data in geographical applications.The emergence of Grid computing coupled with Geographic Information Systems（GIS） provides an excellent framework：GridGIS,which supports fast spatial data retrieval and allows its users to transparently access data from anywhere at any time.GridGIS also causes spatial load unbalancing.This paper presents a new load balancing algorithm（TLB-Chord）,which adopts the tree structure based on the classical Chord algorithm to improve system performance and increase the availability of spatial data.First,the relative researches of GridGIS and spatial load balancing are summarized.Secondly,the special thoughts of the TLB-Chord algorithm are given.The paper discusses how to construct the tree structure based on Chord,divides the peers in the system into three kinds：the only virtual root peer,some task managers and many normal peers,and gives each kind of peers how to work.Then,it is introduced that the TLB-Chord algorithm has three levels to implement the spatial load balancing：the basic level composed by normal peers,the middle level including task managers and the high level having the root peer.The algorithm begins from the basic level.Once it fails to adjust the load,the algorithm will perform the middle level.If the middle level also fails,the algorithm will adopts the high level.Thirdly,a spatial load balancing simulation system is given and the TLB-algorithm（peers connected in Chord based on the tree structure） and the common algorithm（peers connected in the physical order based on a ring structure） are compared through the testing environment in GridGIS,which uses the iterative way,and shows the TLB-Chord algorithm can improve the system performance better.

关 键 词：GIS 网格计算 GridGIS 负载平衡 CHORD 

分 类 号：P208[天文地球—地图制图学与地理信息工程]