无线传感器网络在面向事件监测中蕴藏着巨大的应用价值,但由于传感器节点电源能量耗尽导致经常失效或废弃,因此研究无线传感器网络节能的算法具有重要意义.多路径路由沿多条路径分配能量负载,提高了网络的寿命和质量.需要强调的是均匀...无线传感器网络在面向事件监测中蕴藏着巨大的应用价值,但由于传感器节点电源能量耗尽导致经常失效或废弃,因此研究无线传感器网络节能的算法具有重要意义.多路径路由沿多条路径分配能量负载,提高了网络的寿命和质量.需要强调的是均匀地调节更多节点参与到网络的路由任务能够保护某节点由于负载过重从而能量迅速流失直至节点失效.反之,所有的流量沿最短路径路由,路由不仅拥塞,而且沿源节点和汇聚节点对之间的最佳路由周围的节点由于过载最终缩短了网络寿命.从2个方面展开:1)提出了一种高能效的基于Bezier曲线的多路径路由算法(multipath routing algorithm based on Bezier curve,MPRB),并通过与传统的路由算法比较,实验数据验证了该算法能够获得更好的节能效果;2)基于查询区域划分设计的路由树个数与能耗关系比较了2种高能效的时空查询算法,并通过理论分析与实验仿真研究了查询区域划分方法、划分个数对能耗的影响,结果表明基于角度的查询区域划分方法是一种低能耗、面向绿色计算的方法.展开更多
A novel data streams partitioning method is proposed to resolve problems of range-aggregation continuous queries over parallel streams for power industry.The first step of this method is to parallel sample the data,wh...A novel data streams partitioning method is proposed to resolve problems of range-aggregation continuous queries over parallel streams for power industry.The first step of this method is to parallel sample the data,which is implemented as an extended reservoir-sampling algorithm.A skip factor based on the change ratio of data-values is introduced to describe the distribution characteristics of data-values adaptively.The second step of this method is to partition the fluxes of data streams averagely,which is implemented with two alternative equal-depth histogram generating algorithms that fit the different cases：one for incremental maintenance based on heuristics and the other for periodical updates to generate an approximate partition vector.The experimental results on actual data prove that the method is efficient,practical and suitable for time-varying data streams processing.展开更多
We present a study to show the possibility of using two well-known space partitioning and indexing techniques, kd trees and quad trees, in declustering applications to increase input/output （I/O） paraUelization and ...We present a study to show the possibility of using two well-known space partitioning and indexing techniques, kd trees and quad trees, in declustering applications to increase input/output （I/O） paraUelization and reduce spatial data processing times. This parallelization enables time-consuming computational geometry algorithms to be applied efficiently to big spatial data rendering and querying. The key challenge is how to balance the spatial processing load across a large number of worker nodes, given significant performance heterogeneity in nodes and processing skews in the workload.展开更多
基金Supported by the National High-Tech Research and Development Plan of China under Grant No.2004AA112010 (国家高技术研究发展 计划(863))the National Basic Research Program of China under Grant No.2002CB312005 (国家重点基础研究发展计划(973))
文摘无线传感器网络在面向事件监测中蕴藏着巨大的应用价值,但由于传感器节点电源能量耗尽导致经常失效或废弃,因此研究无线传感器网络节能的算法具有重要意义.多路径路由沿多条路径分配能量负载,提高了网络的寿命和质量.需要强调的是均匀地调节更多节点参与到网络的路由任务能够保护某节点由于负载过重从而能量迅速流失直至节点失效.反之,所有的流量沿最短路径路由,路由不仅拥塞,而且沿源节点和汇聚节点对之间的最佳路由周围的节点由于过载最终缩短了网络寿命.从2个方面展开:1)提出了一种高能效的基于Bezier曲线的多路径路由算法(multipath routing algorithm based on Bezier curve,MPRB),并通过与传统的路由算法比较,实验数据验证了该算法能够获得更好的节能效果;2)基于查询区域划分设计的路由树个数与能耗关系比较了2种高能效的时空查询算法,并通过理论分析与实验仿真研究了查询区域划分方法、划分个数对能耗的影响,结果表明基于角度的查询区域划分方法是一种低能耗、面向绿色计算的方法.
基金The High Technology Research Plan of Jiangsu Prov-ince (No.BG2004034)the Foundation of Graduate Creative Program ofJiangsu Province (No.xm04-36).
文摘A novel data streams partitioning method is proposed to resolve problems of range-aggregation continuous queries over parallel streams for power industry.The first step of this method is to parallel sample the data,which is implemented as an extended reservoir-sampling algorithm.A skip factor based on the change ratio of data-values is introduced to describe the distribution characteristics of data-values adaptively.The second step of this method is to partition the fluxes of data streams averagely,which is implemented with two alternative equal-depth histogram generating algorithms that fit the different cases：one for incremental maintenance based on heuristics and the other for periodical updates to generate an approximate partition vector.The experimental results on actual data prove that the method is efficient,practical and suitable for time-varying data streams processing.
文摘We present a study to show the possibility of using two well-known space partitioning and indexing techniques, kd trees and quad trees, in declustering applications to increase input/output （I/O） paraUelization and reduce spatial data processing times. This parallelization enables time-consuming computational geometry algorithms to be applied efficiently to big spatial data rendering and querying. The key challenge is how to balance the spatial processing load across a large number of worker nodes, given significant performance heterogeneity in nodes and processing skews in the workload.
