一种Ad hoc网络自适应部分多路径机制

对于Ad Hoc网络多路径机制来说,采用过多的路径传输数据会影响网络的资源利用率,同时固定的选取路径数量也不能够使得多路径机制适应各种拓扑情况。提出了自适应部分多路由机制,首先分析分组丢弃概率门限问题,节点使用该门限值判定链路状态,并且根据网络当前的拓扑状态自适应地寻找部分多路径。仿真结果表明,该机制在减少路由建立开销的同时,能够有效保障数据分组传输的可靠性。     

基于AODV动态自适应多路径路由

在AODV的基础上提出了一种自适应多路径路由方法。多路径是在路由发现过程中形成,路径维持是通过各个路径周期性地逆向更新信息分组来实现,这些更新信息分组沿着各个替用的路径测量每一跳的信号强度,只有信号最强的路径才被用来传递数据。提出了协议的两种变化类型,并与相关的两种多路径协议进行性能比较,仿真结果表明,提出的解决方法对于网络性能提高具有实用意义。     

一种无线mesh网络下的可靠路由查询机制

针对无线mesh网络目前存在的资源查找效率不高,路由跳转过多,网络中节点的通信链路易失效等问题,研究并设计了一种基于Chord的无线mesh网络可靠路由查询机制.该机制将Chord应用于无线mesh网络物理拓扑结构,设计了分层和双向查询模型,并在Chord固有的单路径查找模式上加入可靠多路径选择策略,在节点出现失效或链路异常等情况时启用多路径可靠查询方法,有效提高节点间成功通信概率,并对性能进行了分析.     

一种新的无线Adhoc网络中的多路径路由及流量分配算法

结合无线Ad hoc网络与多媒体业务的特点,提出了一种新的适用于在无线Ad hoc网络中传输多媒体业务的多路径路由及每条路径上的流量分配算法.针对多路径路由,优先选择延时最短的路径,在此基础上选择多条路径来满足业务带宽的需求.流量分配算法中使用FEC编码对传输的业务流进行纠错,并给出了根据信道信噪比等特性计算FEC编码速率的算法,该算法能够较好地适应多媒体业务对实时性要求较高的特点,同时能够对无线链路达到最优的利用.仿真结果显示,所提算法能够很好地增加网络的利用率,有效地减小多路径的传输延时.     

基于Click和NS2的多路径域间路由仿真器的设计与实现

针对当前多路径域间路由仿真和性能评估的不足,设计并实现了一个基于Click和NS2的多路径域间路由仿真器MIRS（multi—pathinter—domainroutingsimulator）MIRS通过在传统网络仿真器Ns2中嵌入Click软件路由器来构建,其源代码既可以在仿真器中运行,也可经小幅修改后在现有的真实系统平台上运行,从而有效缩短了实验评估的周期,,而且,MIRS能够准确描述多路径域间路由器转发流量的行为,提高了仿真的准确度。基于模拟网络拓扑以及山东大学校园网拓扑分别进行了单路径路由与多路径路由的仿真对比实验,实验结果表明多路径路由可以更好地改善网络性能,同时也验证了MIRS仿真器的有效性。     

带QoS约束的查询式多播路由协议

随着网络技术以及商业化应用的飞速发展,带QoS约束的多播路由成为必要．在（汹多播路由中,很难取得管理费用、加入延迟和加入成功率以及多播树性能之间的平衡．提出了一种查询式的单路径／多路径自适应多播路由协议,能够在较低费用的情况下保证节点加入多播树的成功率．模拟结果表明,该协议能够很好地同时适应组成员稀疏或密集的情况．     

基于MANET接入Internet的负载均衡机制及其算法

在MANET接入Internet的网络环境中,由于移动节点集中使用某些位置上的网关来实现接入,造成这些网关的负载增加,性能下降.为了能够均衡利用网关及各移动节点,提出了一种新的利用动态网关和多径技术实现MANET接入Internet负载均衡的路由机制.该机制使用多路径进行传输,并在多个候选路径之间按一定的比例均衡分配通信流量;同时,在选择网关时尽量选择低负载的网关,均衡网关的负载.仿真分析结果表明:该算法能有效降低分组的平均传输延迟并提高网络的吞吐率.     

无线传感器网络复数域网络编码合作多路径算法

分析了合作多路径传输中的复数域网络编码问题.提出了在WSN转发节点中使用复数域网络编码和合作多路径机制(CFNC-CM)进行数据分组的传输和转接机制,复数域网络编码的数据分组由中继转接节点进行编码后再转发到多路径进行数据分组的传输.通过仿真实验对2种典型的路由协议在数据分组开销、数据分组传输率和网络生存期等测量参数方面进行了性能分析和比较.仿真实验结果表明:CFNC-CM机制能较好地用于WSN网络中,相对传统机制,CFNC-CM机制能提高5%~15%的性能.     

基于混沌蚁群的自适应路由优化算法

针对无线传感器网络能耗不均衡及路由拓扑过长等现况,基于混沌蚁群与自适应思想,本文提出了一种构建最优节点集并基于该类解集生成最优路径的方法。该方法兼顾能耗与路由拓扑分布,依据区域划分与基于势的跳转概率计算得出最优扇环,通过蚂蚁的改进混沌行为对适应值较高的节点记录并成集,生成并优化网络路由拓扑。结果表明该方法在缩短网络路由拓扑长度的同时有效地减少了并均衡网络能耗,达到延长网络生命周期的目的。     

一种基于SDN的自适应多路径负载均衡策略

针对传统多路径路由方法在复杂网络中的负载不均衡、吞吐量低、网络时延等问题,提出一种基于SDN的自适应多路径负载均衡策略(SDN based adaptive multipath load balancing,SDN-AMLB).利用SDN获取全局网络视图的能力,在控制层结合Adaboost算法进行自适应路由计算实现重路由,计算过程中根据网络节点负载、链路负载和数据包大小进行自适应评估并更新路径表,将评估结果引入模型更新分类器参数,通过Mininet工具进行模拟.结果表明SDNAMLB可提高全网数据传输效率和吞吐量,实现网络负载均衡,满足复杂网络环境中用户对网络传输、时延的要求.     

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.     

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