CRC算法在计算机网络通信中的漏检分析

在计算机网络通信中,为了降低数据通信线路传输的误码率,可以采用一种差错检测控制——循环冗余码验(CRC).介绍了CRC算法的原理、CRC算法的校验规则、CRC算法分析、CRC算法的漏检分析.     

循环冗余校验在千兆以太网系统中的并行实现

介绍了一种CRC-32校验码的半字节并行计算的并行算法及实现.在分析了串行CRC校验原理的基础上,根据电路部分数据位的遗传性和复用性,提出了一种半字节并行的CRC校验的实现方案,通过使用这种并行CRC校验硬件算法有效地同步了以太网介质访问控制器的数据传输速率,同时在电路结构上比串行校验电路简单,节约了近一半的电路面积.这种半字节并行CRC校验算法在以太网系统中通过了仿真测试,证实是一种正确适用的并行实现方案.     

基于DSP的CRC算法的实现

介绍了循环冗余校验CRC算法原理和校验规则,分析了CRC校验码的具体计算方法,给出了使用DSP来实现CRC算法的过程,完成了CRC编码器的DSP实现。最后,将仿真结果与理论值进行比较,仿真结果与理论值一致。     

基于iSCSI协议校验算法的改进

CRC校验作为iSCSI协议中使用最频繁的一种检错机制,其算法的优劣会直接影响协议的执行效率.在分析传统CRC算法低效率的基础上,引入了一种快速并行的CRC算法,并根据iSCSI协议的特点对它进行了改进.测试结果表明,改进后的CRC算法在一定程度上减小了协议对CPU的占用率.     

16位循环冗余校验码(CRC)的原理和性能分析

CRC是一种数据通信中广泛应用的检错方法,文章从编码的数学原理出发,分析了CRC的编码本质、生成/校验矩阵、最小码重等参数,推导了编码应用中的检错概率、漏检错误概率结论,给出了利用CRC纠正单比特错误的实现算法和仿真性能。     

CRC算法的软件实现研究

本文分析了循环冗余校验CRC算法，介绍了该算法的软件实现方法，并给出了Delphi环境下完整程序。     

DNP3.0中CRC算法研究

DNP3.0规约是在欧洲及北美洲比较流行的一种规约,其数据帧都带有CRC校验功能。为了把CRC应用在实际中就需要有正确的算法及相应的程序。本文提出了CRC信息单元编码算法,即以包含若干位的信息块为单位计算CRC的方法,并进行了详细的数学推导,给出了CRC的编码算法流程图。分析了CRC的解码算法并给出了CRC的解码算法流程图。对于从低字节的低位开始计算CRC的情况,提出了计算CRC的信息位反转法。在讨论了DNP3.0中CRC程序流程图的基础上,给出了在keil μ Vision8.08a环境下调试通过的单片机KeilC51程序。     

基于FPGA的PCM基群设备串行通讯CRC校验的实现

在2048kbit/s的PCM基群设备中采用CRC校验方案,可实现准确的串口通信,选用Altera公司的cycloneⅡ系列的EP2C8Q208C8芯片,实现基群设备中CRC串行通信的接收、发送和接口控制功能,采用verilog语言实现CRC算法,并用QuartusⅡ软件平台进行多字节校验仿真,最终下载到芯片上实验,实验结果与理论分析一致,提高了PCM基群设备通信的速率和可靠性.     

用C#实现CRC校验

简要介绍了数据通信中CRC校验的基本原理和常用算法 ,给出了一种用查表法实现多种CRC计算的通用C #源代码 ,并说明了采用查表法计算CRC时某些值得注意的问题。     

CRC纠错原理及其Matlab仿真

CRC(Cyclical Redundancy Checking)循环冗余校验码是一种重要的线性分组码,通过多项式除法检测错误,是在数据通信和数据压缩中广泛应用的检错校验的循环码。本文讨论了CRC的基本原理,纠错检错方法及其算法分析,最后以(7,3)码为例对CRC实行Matlab仿真。     

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