最短路径自适应路由的路径条数及可缓冲的数据包数目

在采用最短路径自适应路由方案的片上网络中,从源节点到目的节点具有多条可能的路径,采用最短路径有助于提高片上网络的效率。片上网络每一级路由器都能缓冲一定量的数据包,从源节点到目的节点的距离越远、路径数目越多,可缓冲的数据包数目越多。处理单元(Processing Element, PE)间数据传输需要的流量控制数据包越少,数据传输的效率越高。本文提出从源节点到目的节点可缓冲数据包数目的两种计算方法,并通过计算机搜索和仿真进行了验证。研究结果有助于提升对采用最短路径自适应路由的片上网络的行为的认识,从而设计更好的PE间数据传输方案。     

一种改进无线传感器网络的环境监测系统设计

为了解决环境监测中远程采集数据的实时传输和对监测数据进行管理分析的问题,设计了一种基于无线传感器网络的远程环境监测系统,通过GPRS技术实现了监测中心与监测终端之间的实时命令控制及数据传输,系统采用了移动汇聚节点的方法,解决节点能量更换频繁且容易产生的"能量空洞"问题,系统测试表明,基于移动汇聚节点的环境监测系统能够延长网络的生命周期,确保各个节点的能量消耗均衡,并且网络整体数据包丢失率和时延与固定汇聚节点的监测系统接近,实现了远程监控数据的实时传输。     

基于三态编解码技术的远程测控系统的设计与实现

设计实现了一种基于三态编解码技术的单总线、多节点远程测控系统.系统以PC作为主机,以单片机应用系统作为控制节点.主机通过并行口实现与从节点的通信与控制.论文详细分析了控制网络中的节点寻址方法以及数据传输过程中的相关协议问题.     

基于结构化P2P的可控匿名通信系统的研究

为防止匿名系统被滥用,在PGACS匿名通信系统模型的基础上,提出了分层架构的结构化P2P匿名通信系统(CACS-BSP)。通过采用基于数据包的加密机制实现匿名的可撤销,结合节点的信誉机制实现对节点自私行为的惩罚机制,使系统具有对匿名的可控性。理论分析表明本系统的匿名性等于Crowds和PGACS系统;经实验模拟发现,本系统在提供较高匿名性的同时,可使系统中自私节点和恶意节点数目的变化对系统的负载影响较小。     

VANET中基于合作式的ADHOC MAC协议

由于车载网VANETs(Vehicular Ad hoc Networks)在道路安全、车流量管理和娱乐应用具有广阔的前景,VANETs的数据传输技术成为研究的焦点。然而,VANETs的拓扑动态变化、车辆快速移动加速了车间通信链路的断裂,降低了链路的可靠性。为此,提出合作式通信机制以提高通信链路的可靠性,并缓解因车辆移动引起的无线道路的恶化。基于ADHOC MAC 方案,提出合作式的ADHOC MAC方案 ,记为CAH-MAC。在CAH-MAC中,一旦发现数据包未能成功传输到目的节点,邻居节点使用未占用的时隙提供合作模式重传数据。通过理论分析,得出合作模式的概率。理论分析和仿真表明,CAH-MAC提高了成功传输数据包的概率,提升了系统吞吐量。     

基于片上网络资源节点的通信协议研究

为了克服总线架构的SoC设计方法不能有效解决片内多处理器系统的通信问题,应用NoC(片上网络)将计算机网络技术移植到芯片设计中,提出了一种适宜于片上网络资源节点通信的单向总线架构。借鉴以太网数据帧格式定义了数据传输协议,利用软核处理器MicroBlazer作为主资源节点,Flash控制器和RS232串口控制器作为从资源节点,在Xilinx FPGA开发板上验证了单向总线架构的可行性。该总线易于扩展资源节点,可实现主资源节点对两个及两个以上从资源节点的同时访问。实验证明,本设计单向总线结构简单,资源节点易于扩展,提高数据传输速率,增强系统性能。     

基于FPGA的CAN总线通信事务的现场测试系统设计

针对CAN总线网络中节点性能的测试应用,研究并设计了基于FPGA的CAN总线通信事务的现场测试系统;该系统可以针对不同属性的被测节点进行接口配置和波特率匹配,同时能够模拟CAN总线主节点,对从节点发送命令或数据,并能实时接收CAN总线上任意被测节点发送的数据。CAN测试节点采用单片机C8051F040内部集成的CAN控制器,单片机通过并行端口实现和FPGA的通信,FPGA通过USB接口实现与上位机之间的数据传输。实验表明,该系统实用性强,可靠性高,并已成功应用于某航天测试设备中。     

车载网中基于合作式的ADHOC MAC协议

由于车载网VANETs(vehicular Ad hoc networks)在道路安全、车流量管理和娱乐应用具有广阔的前景,VANETs的数据传输技术成为研究的焦点。然而,VANETs拓扑动态变化、车辆快速移动车间通信链路的断裂,降低了链路的可靠性。为此,提出合作式通信机制以提高通信链路的可靠性;并缓解因车辆移动引起的无线道路的恶化。基于ADHOC MAC方案,提出合作式的ADHOC MAC方案,记为CAH-MAC。在CAH-MAC中,一旦发现数据包未能成功传输到目的节点,邻居节点使用未占用的时隙提供合作模式重传数据。通过理论分析,得出合作模式的概率。理论分析和仿真表明,CAH-MAC提高了成功传输数据包的概率,提升了系统吞吐量。     

一种基于能量均衡的地理路由协议设计

针对无线传感器网络中无线链路不稳定与节点能耗不均衡等问题,提出一种基于能量均衡的地理路由协议。在路径构建阶段,为了避免传统地理路由中贪婪转发引起的某些节点过度使用,文章将簇作为数据传输的基本单元,并对节点设置能量阈值。在路由度量选择时,综合考虑簇内节点数目和簇中心到汇聚节点的距离,以便均衡簇间节点能量消耗。在数据传输阶段,利用协同通信与网络编码技术提高数据传输可靠性。最后,理论分析与数值实验同时表明:所提协议能够显著地提高数据包传输成功率,减少数据包重传次数。     

基于位置信息的WSN数据汇聚路由算法

文章以无线传感器网络在建筑环境下的应用为研究背景,根据建筑能耗监测系统中无线数据传输网络特性,按位置信息对网络节点进行分簇,设计网络2级结构模型;并设计适合该网络模型的基于位置信息的WSN数据汇聚路由算法,保证簇头节点从邻居列表中选择最佳下一跳节点,最终实现与Sink节点的数据通信功能。仿真分析表明所设计的路由算法具有低时延、高可靠性、节能等优点。     

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     

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

正~~