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有效的位置依赖空间查询的数据访问方法

Efficient Data Access for Location-Dependent Spatial Queries

  • 摘要: 当移动环境包含轻设备,网络连接丢失和资源匮乏,例如低电池能力和有限的存储等,成为有效地支持移动无线设备的主要问题之一。本文首先提出了一个基于检索的,端对端的数据访问方法,使用一种新的层次式基于位置顺序索引HLBS。继而提出一种新的分布式最近先广播算法Nearest First Broadcast (NFB)。HLBS和NFB都是针对无线广播环境中移动端对端设备设计的。该系统反应时间短,因为客户只联系一个合格的服务提供方,访问HLBS并使用NFB迅速地检索数据以回答查询。HLBS and NFB根据单独客户的位置来为空间对象建立索引,并将索引按照安排的顺序进行转换,使得即使用户调整了部分索引,也能处理空间查询。因此,该设计支持快速和能量有效的服务。在性能评价实验中,我们比较了本文提出的算法和基于R-tree和Hilbert-curve air 索引的算法。结果显示,所提出的使用HLBS索引的数据传播算法,对于范围查询和最近邻居查询,都是可扩展且能量有效的。

     

    Abstract: When the mobile environment consists of light-weight devices, the loss of network connectivity and scarce resources, e.g., low battery power and limited memory, become primary issues of concern in order to effciently support portable wireless devices. In this paper, we propose an index-based peer-to-peer data access method that uses a new Hierarchical Location-Based Sequential (HLBS) index. We then propose a novel distributed Nearest First Broadcast (NFB) algorithm. Both HLBS and NFB are specifically designed for mobile peer-to-peer service in wireless broadcast environments. The system has a lower response time, because the client only contacts a qualified service provider by accessing the HLBS and quickly retrieves the data to answer the query by using NFB. HLBS and NFB design the index for spatial objects according to the positions of individual clients and transfer the index in the order arranged so that the spatial query can be processed even after the user tunes the partial index. Hence, this design can support rapid and energy-effcient service. A performance evaluation is conducted to compare the proposed algorithms with algorithms based on R-tree and Hilbert-curve air indexes. The results show that the proposed data dissemination algorithm with the HLBS index is scalable and energy effcient in both range queries and nearest neighbor queries.

     

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