基于位置加权粒子群算法的WSNs能量优化

针对无线传感器网络经典分簇协议Leach存在能量消耗过大的问题,提出了一种基于LEACH的改进协议。该协议采用位置加权粒子群算法结合对惯性权值、学习因子的调整,优化LEACH协议的簇头选择机制,将节点剩余能量、簇间距离及簇头到基站的距离作为适应度函数因素,调节簇及选举簇头。仿真结果表明,改进的协议使整个网络能量消耗达到相对均衡,大大减少了节点能量消耗,从而延长了网络寿命。     

煤矿巷道无线传感器网络的LEACH协议改进

将LEACH协议应用于环境复杂的煤矿巷道中存在不足,为了使LEACH协议更适用于煤矿巷道,对LEACH协议进行改进。首先,本文对选择簇头的阈值函数进行调整,加入节点剩余能量、位置信息以及邻节点数量因素;其次,改进建簇算法,节点通过计算与簇头节点和汇聚节点之间的距离来判断加入簇头还是与汇聚节点直接通信;最后,改进簇间通信机制,簇头之间通过多跳方式进行数据传输,并根据能量和距离信息选择下一跳簇头节点,提高簇间数据传输的可靠性。仿真实验表明,改进后的LEACH协议可以有效降低煤矿巷道无线传感器网络能耗,延长网络生命周期。     

基于节点权值的簇头选举优化算法

LEACH是无线传感器网络中一种经典的降低网络耗能的分簇路由算法,该算法可有效的延长网络的生命周期,具有平面路由协议无可比拟的优越性。但其簇头选举机制是随机的,没有考虑候选节点的剩余能量等因素。本文基于LEACH提出了一种改进算法,通过节点权值来选择簇头,权值是本轮候选节点的剩余能量、节点密度和距离基站远近的一种数学关系的度量。依此来均衡网络负载,延长整个网络的生命周期。     

基于模糊算法和最短路径的LEACH改进协议

无线传感器网络是由部署在监测区域的大量传感器节点通过无线通信形成的自组织网络系统,传感器节点存在着电源能量、计算和通信能力有限等制约因素.为了均衡无线传感器网络中节点能量的消耗,延长无线传感器网络的工作寿命,提出一种基于模糊算法和最短路径的LEACH改进协议ILAFASP.该协议簇头选举时,采用模糊算法考虑相对节点剩余能量、相对集中度、相对节点度计算出每个节点的优先度,根据优先度选举簇头;在数据传送阶段,在源节点和基站之间建立最短多跳数据传输路径,减少簇头数据传输的能耗.仿真表明,该协议能够均衡节点能量的消耗,延长整个网络的工作寿命.     

基于能量和距离的分簇式WSN路由协议设计

针对典型分簇式路由LEACH协议随机选取簇头节点、分簇不合理等造成的网络节能不理想的情况,提出了一种基于能量和距离的分簇式路由协议EDCRP。通过把节点到基站的距离和其剩余能量作为基站选取簇头的参考因素,借鉴遗传算法中的轮盘赌思想选择簇头,并设置簇头之间的距离阈值,合理选取和分布簇头。通过在Matlab环境下仿真实验,比较了LEACH、DIRECT和EDCRP协议。实验表明,EDCRP协议可改善负载均衡和有效地延长网络生存时间。     

基于AP聚类的分簇网络拓扑控制算法

针对无线传感器网络LEACH协议分簇过程中存在的簇头节点分布不均匀、选取时未考虑节点剩余能量的问题,提出了一种基于近邻传播聚类的自适应双选分簇网络拓扑控制算法(ADSAP)。ADSAP在参考AP聚类算法中聚类中心的选举策略的同时引入参考节点概念,能够根据当前参考节点的状态选择性的使用基于AP聚类的分簇策略或基于参考节点的分簇策略。两种分簇策略综合考虑了无线传感器网络中各个节点的剩余能量以及节点与汇聚节点间距离因素,能够在获取分布较为均匀的簇头节点的同时避免出现自身剩余能量较低的节点当选簇头节点的情况出现。仿真结果表明:基于ADSAP分簇算法的LEACH协议(ADSAPLEACH)相比于原LEACH协议分簇算法能够使簇头分布更加均匀、簇头选举更为合理、网络能耗更加均衡,有效延长了整个传感器网络的寿命。     

无线传感器网络LEACH协议生命周期的改进

无线传感器网络跨层协议中,LEACH协议不考虑节点参数情况,采用随机概率方法选择簇首,不能保证能量较大的节点被选为簇首(CH),进而会降低网络寿命.为了有效选择簇首,提出改进的I-LEACH协议,将节点的剩余能量及节点与基站(BS)的距离作为优选条件,通过将网络划分为四个象限加以实现.实验仿真结果表明,在网络寿命、传输到基站的数据量、所用时间和能耗等性能方面,I-LEACH协议优于LEACH协议,延长了网络的生命周期.     

基于能量均衡策略的无线传感器网络LEACH协议改进

在原有的LEACH协议分簇算法的基础上,针对无线传感器网络中节点分布不均匀的情况,以节点的剩余能量与节点到基站的距离相结合来改进其阈值,作为节点成为簇首的随机数值的调整权值,改进其LEACH协议分簇算法。仿真实验结果表明,该改进的算法有效地均衡了节点的能量消耗,可以显著地延长网络的寿命周期。     

无线传感器网络LEACH路由协议的簇头多跳算法

针对无线传感器网络LEACH路由协议簇头分布不均匀、网络拓扑和能量消耗不均衡的问题,提出基于DCHS簇头选择策略的无线传感器网络LEACH路由协议的簇头多跳算法LEACH-MUL。该算法在非簇头节点中选择一个节点作为通信簇头节点,其它簇头节点进行融合后的数据发送到该簇头节点并进行数据再次融合,最后通信簇头节点将数据融合后的结果数据发送到基站BS。LEACH-MUL算法能够有效地均衡节点能耗,提高能量利用率,延长网络寿命。     

异构传感网中一种能量均衡非均匀分簇算法

分簇路由协议是无线传感网中减少能量消耗、延长网络寿命的一种重要手段.大部分分簇路由协议基于均匀分簇算法,却忽略了无线传感网单跳路由协议中远离基站的簇头需要消耗更多能量,从而导致整个网络能量消耗不均匀.针对以上问题,提出异构传感网中一种能量均衡非均匀分簇算法.一方面,簇头选取阶段,在考虑节点剩余能量的同时,引入非均匀竞争机制;另一方面,簇构建阶段,为节点选取簇头时,不仅考虑簇头剩余能量、节点与簇头间距,也考虑节点与基站间距.仿真结果表明,与LEACH,SEP,DEEC分簇算法相比,该算法有效均衡了簇头的能量消耗、延长了网络寿命.     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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     

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