延长传感器网络寿命,减少能量消耗,是无线传感器网络的研究重点,本文在研究层次结构及有效能量的路由协议代表LEACH(low energy adaptive clustering hierarch,低功耗自适应集簇分层型)协议的基础上,提出一种高效聚类路由算法(LEACH-Ⅱ...延长传感器网络寿命,减少能量消耗,是无线传感器网络的研究重点,本文在研究层次结构及有效能量的路由协议代表LEACH(low energy adaptive clustering hierarch,低功耗自适应集簇分层型)协议的基础上,提出一种高效聚类路由算法(LEACH-Ⅱ)。该算法在簇头选举中综合考虑了节点剩余能量、平均能量和最大能量,并限制了各簇的成员数量,同时簇头之间形成第一簇头,利用多跳方式平衡网络的负载。仿真结果表明,改进的算法降低了能量的消耗,延长了网络的生存周期,保证了系统的负载均衡。展开更多
LEACH(Low Energy Adaptive Clustering Hierarchy)是比较流行的的无线传感器网络协议协议之一,因其能量有效性高而且网络延迟低。本文在LEACH协议的基础上进行改进并提出了一种高能效无线传感器网络协议——LEACH-S。仿真结果表明,和LE...LEACH(Low Energy Adaptive Clustering Hierarchy)是比较流行的的无线传感器网络协议协议之一,因其能量有效性高而且网络延迟低。本文在LEACH协议的基础上进行改进并提出了一种高能效无线传感器网络协议——LEACH-S。仿真结果表明,和LEACH相比,LEACH-S协议具有更好的能量有效性,并且提高了无线传感器网络的寿命。展开更多
无线传感器网络由大量能量有限的传感器节点组成,这些节点一般都是靠电池供电。如何在这种情况下,尽量延长网络的生存周期是研究的热点问题。基于分簇的无线传感器网络路由算法不论是在网路生存周期方面,还是在数据融合方面都比自组织...无线传感器网络由大量能量有限的传感器节点组成,这些节点一般都是靠电池供电。如何在这种情况下,尽量延长网络的生存周期是研究的热点问题。基于分簇的无线传感器网络路由算法不论是在网路生存周期方面,还是在数据融合方面都比自组织算法表现出了很大的优势。文中提出了一种基于能量和距离的ED-LEACH(Energy and Distance-LEACH)改进算法,在簇头的选举和簇的生成两个阶段都综合考虑了能量和距离这两个因素。仿真表明该算法较LEACH算法显著地延长了网络的生存期。展开更多
Four sites located in the north-eastern region of the United States of America have been chosen to investigate the impacts of soil heterogeneity in the transport of solutes(bromide and chloride)through the vadose zone...Four sites located in the north-eastern region of the United States of America have been chosen to investigate the impacts of soil heterogeneity in the transport of solutes(bromide and chloride)through the vadose zone(the zone in the soil that lies below the root zone and above the permanent saturated groundwater).A recently proposed mathematical model based on the cumulative beta distribution has been deployed to compare and contrast the regions'heterogeneity from multiple sample percolation experiments.Significant differences in patterns of solute leaching were observed even over a small spatial scale,indicating that traditional sampling methods for solute transport,for example the gravity pan or suction lysimeters,or more recent inventions such as the multiple sample percolation systems may not be effective in estimating solute fluxes in soils when a significant degree of soil heterogeneity is present.Consequently,ignoring soil heterogeneity in solute transport studies will likely result in under-or overprediction of leached fluxes and potentially lead to serious pollution of soils and/or groundwater.The cumulative beta distribution technique is found to be a versatile and simple technique of gaining valuable information regarding soil heterogeneity effects on solute transport.It is also an excellent tool for guiding future decisions of experimental designs particularly in regard to the number of samples within one site and the number of sampling locations between sites required to obtain a representative estimate of field solute or drainage flux.展开更多
文摘延长传感器网络寿命,减少能量消耗,是无线传感器网络的研究重点,本文在研究层次结构及有效能量的路由协议代表LEACH(low energy adaptive clustering hierarch,低功耗自适应集簇分层型)协议的基础上,提出一种高效聚类路由算法(LEACH-Ⅱ)。该算法在簇头选举中综合考虑了节点剩余能量、平均能量和最大能量,并限制了各簇的成员数量,同时簇头之间形成第一簇头,利用多跳方式平衡网络的负载。仿真结果表明,改进的算法降低了能量的消耗,延长了网络的生存周期,保证了系统的负载均衡。
文摘LEACH(Low Energy Adaptive Clustering Hierarchy)是比较流行的的无线传感器网络协议协议之一,因其能量有效性高而且网络延迟低。本文在LEACH协议的基础上进行改进并提出了一种高能效无线传感器网络协议——LEACH-S。仿真结果表明,和LEACH相比,LEACH-S协议具有更好的能量有效性,并且提高了无线传感器网络的寿命。
文摘无线传感器网络由大量能量有限的传感器节点组成,这些节点一般都是靠电池供电。如何在这种情况下,尽量延长网络的生存周期是研究的热点问题。基于分簇的无线传感器网络路由算法不论是在网路生存周期方面,还是在数据融合方面都比自组织算法表现出了很大的优势。文中提出了一种基于能量和距离的ED-LEACH(Energy and Distance-LEACH)改进算法,在簇头的选举和簇的生成两个阶段都综合考虑了能量和距离这两个因素。仿真表明该算法较LEACH算法显著地延长了网络的生存期。
文摘Four sites located in the north-eastern region of the United States of America have been chosen to investigate the impacts of soil heterogeneity in the transport of solutes(bromide and chloride)through the vadose zone(the zone in the soil that lies below the root zone and above the permanent saturated groundwater).A recently proposed mathematical model based on the cumulative beta distribution has been deployed to compare and contrast the regions'heterogeneity from multiple sample percolation experiments.Significant differences in patterns of solute leaching were observed even over a small spatial scale,indicating that traditional sampling methods for solute transport,for example the gravity pan or suction lysimeters,or more recent inventions such as the multiple sample percolation systems may not be effective in estimating solute fluxes in soils when a significant degree of soil heterogeneity is present.Consequently,ignoring soil heterogeneity in solute transport studies will likely result in under-or overprediction of leached fluxes and potentially lead to serious pollution of soils and/or groundwater.The cumulative beta distribution technique is found to be a versatile and simple technique of gaining valuable information regarding soil heterogeneity effects on solute transport.It is also an excellent tool for guiding future decisions of experimental designs particularly in regard to the number of samples within one site and the number of sampling locations between sites required to obtain a representative estimate of field solute or drainage flux.
