零拷贝技术在网络流量控制系统中的应用

分析数据包的传输过程,分析数据拷贝操作的CPU消耗和时间代价,并研究当前的零拷贝技术PF_RING,设计出一种改进的基于操作系统的零拷贝实现方法,该方法利用Linux的内存共享和DMA技术实现数据包传输过程中内存的零拷贝,同时解决了同步问题,优化了Linux的内存管理,该方法能消除数据包传输过程中内存拷贝对CPU的消耗,缩短数据包行走路径,并进行了测试,结果表明应用零拷贝后系统效率提升明显.     

RAID中零拷贝技术研究

从实际测试和理论分析角度出发,研究了采用零拷贝技术对提高RAID性能的重要性.研究结果表明零拷贝技术对RAID性能有很大影响,尤其是在嵌入式环境下,必须采用零拷贝实现RAID核心逻辑,避免昂贵的内存拷贝操作.     

软磁盘反拷贝技术探讨

阐述软磁盘反拷贝技术及其基本实现方法,并给出实现方法的源程序。     

基于WINCAP技术的网络零拷贝技术研究

本文分析了网络零拷贝技术,并给出具体实现方法.     

基于Linux系统的高性能报文捕获技术

零拷贝技术是提高通用计算机报文采集性能的重要技术手段,但是目前通用的方案存在不易移植的缺点。针对这一问题,本文提出一种基于Linux系统平台下的新型零拷贝报文捕获技术PF_DMA。该方法通过对系统内核函数的扩展、替换,在不破坏原有网卡驱动程序结构的基础上实现报文的零拷贝捕获,且易于实现在不同网卡驱动程序间移植。     

一种并行计算通信优化策略

为了解决在ABEEMσπ模型电荷分布计算中,基于Cholesky分解并行算法在通信过程中不断增长引起的通信开销和同步开销问题,采用linux并行计算集群系统层通信优化方法,设计并实现了系统层零拷贝通讯优化方法,以及可卸载的LKM模块机制缩短开发和测试时间,减少数据拷贝冗余的基于地址映射的零拷贝技术,解决了通讯延迟等问题。测试结果表明:基于零拷贝的通讯优化方法保证了数据信息的及时性、高效性与准确性,大大提高了Cholesky分解并行算法的通信性能。     

多点还原卡基于Windows的局域网硬盘间差异拷贝技术解析

硬盘数据维护是学校机房管理中最重要的工作之一。阐述了基于硬盘还原卡的数据传送方案，介绍了网络拷贝技术及网络差异拷贝技术，并指出了实现的流程。     

DVD录像机中拷贝保护的研究与实现

系统研究DVD录像机有关的拷贝保护技术,综合不同的规范,定义出如何在一个DVD录像机系统中实现完整的拷贝保护,并在基于LSILogic公司DMN8652的DVD录像机参考设计中实现了Macrovision和CGMS的拷贝保护,软件上基于vxWorks实时操作系统和C语言完成。     

应用PCR—SSCP技术从显微切割的人染色体17q11—12探针池批量分离单拷贝片段的研究

将ＤＮＡ单链构象多态（ＳＳＣＰ）检测的原理，应用于“显微切割的人染色体１７ｑ１１—１２探针池”批量分离单拷贝片段，取得了很好效果。从筛选出的７４个次级单拷贝中有效地鉴定出３７个非同源的单拷贝片段。这比传统的仅限于长度比较而确认的非同源单拷贝片段（１２个）多出２５个．其中部分已经ＤＮＡ测序证实。结果提示：采用ＳＳＣＰ技术区分相似分子量单拷贝片段的同源性，可显著地提高从“显微切割探针池”分离和克隆非同源单拷贝片段的效率。本文还将一部分单拷贝片段作为探讨，与人基因组ＤＮＡ的限制性片段作Ｓｏｕｔｈｅｒｎ印迹杂交，结果均只显示单一杂交带，说明单拷贝ＤＮＡ片段的结论是可靠的。     

油气勘探开发云虚拟机内存迁移算法改进研究

虚拟机动态迁移对数字油田的云平台安全建设具有重要意义。文中讨论云计算关键技术——虚拟化技术中虚拟机动态迁移机制。针对预拷贝迁移方法停机过长这一问题,在预拷贝方法的基础上,提出基于标识的动态迁移方法,能够有效地减少迁移时间,提高迁移效率。首先,新增一个计数器用于记录脏页数量,以此判断是否为频繁改动脏页;然后,设置一个window值,当频繁改动脏页的数量达到window值,将脏页全部发送至目标服务器。该方法避免了最后一次传送时页面过多而造成虚拟机停机时间过长的问题。实验结果表明,该方法在迁移时间和数据传输量上明显优于预拷贝方法,提高了虚拟机迁移效率。     

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

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