针对无线传感器网络低功耗自适应集簇分层(Low Energy Adaptive Clustering Hierarchy,LEACH)路由协议因能耗不均衡导致节点过早死亡的问题,提出了一种基于遗传算法和蚁群算法改进的LEACH路由协议。在分簇阶段,通过遗传算法选举合理的...针对无线传感器网络低功耗自适应集簇分层(Low Energy Adaptive Clustering Hierarchy,LEACH)路由协议因能耗不均衡导致节点过早死亡的问题,提出了一种基于遗传算法和蚁群算法改进的LEACH路由协议。在分簇阶段,通过遗传算法选举合理的簇头节点并根据节点的分布划分簇群;在数据传输阶段,通过蚁群算法使簇头节点尽可能选择能量充足且距离较短的路径进行数据传输。仿真结果表明,与传统的分簇路由协议LEACH和LEACH-C相比,改进算法可以使网络的能量消耗更加均衡,并延长网络的生命周期。展开更多
The necessity to saline and sodic waters is sometimes used for irrigating agricultural activities under certain circumstances, but it is important to note that the use of these waters comes with specific consideration...The necessity to saline and sodic waters is sometimes used for irrigating agricultural activities under certain circumstances, but it is important to note that the use of these waters comes with specific considerations and limitations. One way to decrease undesirable effects of sodic waters on the physical and chemical properties of soils is to apply organic and chemical amendments within the soil. This study aimed to assess the effectiveness of saline water on soil acidity, alkalinity and nutrients leaching in sandy loamy soil at Bella flower farm, in Rwamagana District, Rwanda. The water used was from the Muhazi Lake which is classified as Class I (Saline water quality). Column leaching experiments using treated soils were then conducted under saturated conditions. The soil under experimental was first analyzed for its textural classification, soil properties and is classified as sandy loamy soil. The t-test was taken at 1%, 5% and 10% levels of statistical significance compared to control soil. The results indicated that the application of saline water to soils caused an increase in some soil nutrients like increase of Phosphorus (P), Potassium (K<sup>+</sup>), Magnesium (Mg2<sup>+</sup>), Sulphur (S), CN ratio and Sodium (Na<sup>+</sup>) and decreased soil texture, physical and chemical properties and remained soil nutrients. Consequently, the intensive addition of saline water leachates to soil in PVC pipes led to decreased of soil EC through leaching and a raiser Soluble Sodium Percentage (SSP). The rate of saline water application affected the increase accumulation of SAR and Na% in the top soil layers. The study indicated that saline water is an inefficient amendment for sandy soil with saline water irrigation. The study recommends further studies with similar topic with saline water irrigation, as it accentuated the alkalinity levels.展开更多
无线传感器网络(WSN)数据传输离不开路由协议,路由协议是其组网的基础.由于WSN是一种资源受限网络,尤其是能量的受限,因此路由协议必须维持较小的路由信息并尽可能的减少能耗.文中从其体系结构、协议栈、网络层次等几个方面分析介绍了...无线传感器网络(WSN)数据传输离不开路由协议,路由协议是其组网的基础.由于WSN是一种资源受限网络,尤其是能量的受限,因此路由协议必须维持较小的路由信息并尽可能的减少能耗.文中从其体系结构、协议栈、网络层次等几个方面分析介绍了无线传感器网络,在对传感器网络路由协议作了充分了解的基础上深入研究了经典的聚类路由算法——LEACH(Low Energy Adaptive Clustering Hierarchy),提出了对它的改进方案并用OPNET对改进前后的算法进行了仿真比较.仿真结果证明了改进后算法的有效性,并且在能耗和网络生存时间上比LEACH有了提高.展开更多
无线传感网络低功耗路由的研究对于延长无线传感网络的生存周期具有重要的意义。针对多种类型数据同时采集的异构无线传感器网络,提出了LEACH改进协议—可变通信周期策略的能量均衡成簇协议ACPSEB-LEACH(Alterable Communication Period...无线传感网络低功耗路由的研究对于延长无线传感网络的生存周期具有重要的意义。针对多种类型数据同时采集的异构无线传感器网络,提出了LEACH改进协议—可变通信周期策略的能量均衡成簇协议ACPSEB-LEACH(Alterable Communication Period Strategy and Energy Balanced-LEACH),该协议从抑制节点数据发送量方面出发,将数据采集周期与数据通信周期分离,采取簇内可变通信周期策略以减少部分节点的能量消耗。在此基础上,引入节点活跃度因子进行簇头选举公式优化和成簇优化,实现全局网络能量均衡。仿真表明,改进后的协议在延长网络生存周期、平衡全局能量上有更好的效果。展开更多
文摘针对无线传感器网络低功耗自适应集簇分层(Low Energy Adaptive Clustering Hierarchy,LEACH)路由协议因能耗不均衡导致节点过早死亡的问题,提出了一种基于遗传算法和蚁群算法改进的LEACH路由协议。在分簇阶段,通过遗传算法选举合理的簇头节点并根据节点的分布划分簇群;在数据传输阶段,通过蚁群算法使簇头节点尽可能选择能量充足且距离较短的路径进行数据传输。仿真结果表明,与传统的分簇路由协议LEACH和LEACH-C相比,改进算法可以使网络的能量消耗更加均衡,并延长网络的生命周期。
文摘The necessity to saline and sodic waters is sometimes used for irrigating agricultural activities under certain circumstances, but it is important to note that the use of these waters comes with specific considerations and limitations. One way to decrease undesirable effects of sodic waters on the physical and chemical properties of soils is to apply organic and chemical amendments within the soil. This study aimed to assess the effectiveness of saline water on soil acidity, alkalinity and nutrients leaching in sandy loamy soil at Bella flower farm, in Rwamagana District, Rwanda. The water used was from the Muhazi Lake which is classified as Class I (Saline water quality). Column leaching experiments using treated soils were then conducted under saturated conditions. The soil under experimental was first analyzed for its textural classification, soil properties and is classified as sandy loamy soil. The t-test was taken at 1%, 5% and 10% levels of statistical significance compared to control soil. The results indicated that the application of saline water to soils caused an increase in some soil nutrients like increase of Phosphorus (P), Potassium (K<sup>+</sup>), Magnesium (Mg2<sup>+</sup>), Sulphur (S), CN ratio and Sodium (Na<sup>+</sup>) and decreased soil texture, physical and chemical properties and remained soil nutrients. Consequently, the intensive addition of saline water leachates to soil in PVC pipes led to decreased of soil EC through leaching and a raiser Soluble Sodium Percentage (SSP). The rate of saline water application affected the increase accumulation of SAR and Na% in the top soil layers. The study indicated that saline water is an inefficient amendment for sandy soil with saline water irrigation. The study recommends further studies with similar topic with saline water irrigation, as it accentuated the alkalinity levels.
文摘无线传感器网络(WSN)数据传输离不开路由协议,路由协议是其组网的基础.由于WSN是一种资源受限网络,尤其是能量的受限,因此路由协议必须维持较小的路由信息并尽可能的减少能耗.文中从其体系结构、协议栈、网络层次等几个方面分析介绍了无线传感器网络,在对传感器网络路由协议作了充分了解的基础上深入研究了经典的聚类路由算法——LEACH(Low Energy Adaptive Clustering Hierarchy),提出了对它的改进方案并用OPNET对改进前后的算法进行了仿真比较.仿真结果证明了改进后算法的有效性,并且在能耗和网络生存时间上比LEACH有了提高.
文摘无线传感网络低功耗路由的研究对于延长无线传感网络的生存周期具有重要的意义。针对多种类型数据同时采集的异构无线传感器网络,提出了LEACH改进协议—可变通信周期策略的能量均衡成簇协议ACPSEB-LEACH(Alterable Communication Period Strategy and Energy Balanced-LEACH),该协议从抑制节点数据发送量方面出发,将数据采集周期与数据通信周期分离,采取簇内可变通信周期策略以减少部分节点的能量消耗。在此基础上,引入节点活跃度因子进行簇头选举公式优化和成簇优化,实现全局网络能量均衡。仿真表明,改进后的协议在延长网络生存周期、平衡全局能量上有更好的效果。
