基于能量均衡的ZigBee网络路由优化

为了提高网络中节点的能量利用率,提出了一种基于能量均衡的ZigBee路由算法.启动路由发现之前,首先在邻居表中搜索目的节点,然后在路由过程中给能量偏低的节点添加能量标志位,减少能量偏低节点的使用几率.采用仿真对比实验测试了算法的有效性和优越性,实验结果表明,算法不仅能有效地均衡各节点之间的能量,提高网络节点的存活率,而且能减少网络能量消耗,延长网络的生存时间,性能优于对比算法.     

无线传感网中电池感知的双向搜索路由协议

在无线传感器网络(WSN)中,当有数据流传输时,一些节点会因网络能量分布不均而过早失效,使得源节点不得不通过另一条更长且低效的路径才能将数据包路由至目的节点,从而影响网络寿命.为了延长网络的生存时间,需要设计能量有效的协议,适应传感器网络的特点.提出了一种电池感知的双向搜索路由(battery-aware bi-directional searchrouting protocol,BAR-BIDS)协议,该协议通过改进深度优先搜索,能在网络中已有部分节点因能量耗尽而失效的情况下,找到一条跳数相对较少的路径,从而减少网络中的能量消耗.且该协议能较好感知节点的电池状态,减少节点电池的放电损耗.仿真结果表明,当网络中有数据流传输时,BAR-BIDS协议能较好均衡全网节点的能量消耗、延长网络存活时间.     

一种基于ZigBee树状路由协议的改进算法ATSPF

ZigBee现有的树状路由协议是根据节点间的父子关系创建路由并进行数据传输,这样容易产生较长的路径并加重父节点的处理任务。提出一种基于树状路由协议的改进算法ATSPF,将ZigBee网络地址转换为逻辑索引值列表,根据索引值计算出节点所有邻居到目的节点的跳数,选择跳数最少的邻居为下一跳来建立路由。仿真结果表明,ATSPF可以有效减少路由跳数、降低分组丢失率、减小节点间通信时延、降低协调器的能量消耗、延长网络生存时间。     

节点分簇和最佳距离相融合的传感器网络路由算法

针对当前路由算法由于无线传感器网络节点分布不均匀、 节点能耗过快等因素严重影响其生存时间的问题, 提出一种传感器节点分簇与最佳距离相融合的无线传感器网络路由算法. 该算法先模拟生物细胞的连接过程实现传感器网络节点的分簇, 再权衡网络生存时间和能量消耗间的关系, 根据簇首与基站间的距离确定数据路由 的最优路径, 最后采用MATLAB R2014b工具箱编程实现路由算法. 将该算法与其他算法进行对比实验, 结果表明, 该算法可以延长整个传感器网络的生存时间, 有效减少网络能耗, 提高了能量的利用率.     

采用邻居节点的改进ZigBee路由选择算法

在无线传感网络中,路由选择是高效使用网络、延长全网络寿命的关键之一.为了提高网络效率和节省网络整体能耗,提出了一种路由选择优化算法,该算法利用没连接到的邻居节点进行数据路由选择,以减少从源节点到目的节点的跳数,进而达到提高网络效率和节省能耗的目的.通过仿真实验对比分析了改进前后的实际效果,实验结果表明改进后的路由选择优化算法减少了ZigBee节点间路由的跳数和延迟,提高了路由效率,节省网络整体能耗.     

基于ZigBee的无线传感器网络的自愈功能

无线传感器网络(wireless sensor network,WSN)中如何延长路由节点的生命期和保证网络正常运行非常重要.以WSN主控芯片CC2430为硬件基础,建立了在ZigBee协议下固定节点的链状网络路由模型,提出了一种网络自愈的方法,即为每跳路由节点配备一个备用路由节点,利用高斯算法对各路由节点接收信号强度(received signal strength indi-cation,RSSI)值进行检测,依据检测的RSSI值判定电池的供电情况,进而决定是否启动处于睡眠的备用路由代替当前路由承担相应的工作.实验结果表明,在没有环境因素的情况下,可以较好地实现自愈功能.     

一种基于能量和距离的多级能量异构传感器网络路由算法

为了能有效地利用节点能量的异构性,降低网络能耗、延长网络稳定周期,提出了一种同时考虑节点剩余能量和节点至基站距离的多级能量异构无线传感器网络的分簇路由算法.在节点簇间综合考虑簇头剩余能量及其与基站的通信能耗,以选择合适的下一跳路由节点.仿真结果表明,该算法可以有效地均衡网络能量消耗,延长网络稳定周期.该路由算法在维持节点存活个数、降低网络能量消耗及增加网络数据传输吞吐量等指标方面优于几种常见传感器网络路由算法,表明在综合考虑能量和距离等因素后能够获得比单一考虑能量或者距离的算法更优的运行结果.     

无线传感器网络中基于学习自动机的路由算法

针对无线传感器网络节点能量有效问题,在LEACH协议算法的基础上,本文提出一种基于学习自动机的路由算法,该算法结合节点的剩余能量与节点的邻居信息,在选择簇头上,通过降低能量过低的节点成为簇头的概率,尽可能地进行能量均衡.仿真结果表明本文算法减少了网络的能量消耗,延长了网络生存时间.     

无线传感器网络中基于学习自动机的路由算法

针对无线传感器网络节点能量有效问题,在LEACH协议算法的基础上,本文提出一种基于学习自动机的路由算法,该算法结合节点的剩余能量与节点的邻居信息,在选择簇头上,通过降低能量过低的节点成为簇头的概率,尽可能地进行能量均衡.仿真结果表明本文算法减少了网络的能量消耗,延长了网络生存时间.     

基于邻居表查询的ZigBee多播路由算法

由于ZigBee网络需要将信息以多播的方式进行传递,部分节点多次传输消耗大量能量,导致节点死亡,为缓解这个问题,提出了基于邻居表查询的ZigBee多播路由算法.该算法结合邻居表查询和ZigBee分布式地址分配特性,对ZigBee网络多播转发节点选择进行优化,使一个节点能给多个目的节点转发信息.仿真结果证明该算法减少了路由开销,节约了网络的能量,提高了网络的可靠性.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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