多核系统的多线程并行计算分析

基于多核系统下编程环境的变化,比较了各类编程语言对并行计算的支持情况,并利用多线程实现了多核系统下定积分计算,结果表明在多核环境下多线程技术有良好的应用价值。     

PC并行口I/O扩展的探讨

利用3个TTL集成块，将一个PC并行口扩展成3个I/O口，该电路结构简单、易于实现，配备相应的控制软件后可方便地应用于各种控制电路中．     

并行I/O技术在海洋数值模式中的应用研究

在海洋数值模拟过程中,随着计算区域的扩大以及计算精度的提升,大量数据输出使得I/O效率成为系统整体性能提升的一个瓶颈。针对这一问题,使用并行I/O技术对系统的输出模块进行优化,并与传统的几种串行I/O方式在不同节点,以及不同计算规模下进行性能比较。通过实验研究数据,对不同I/O方式的不同特点和不同适用场景进行分析,证明在海洋数值模式中使用并行I/O技术切实可行,并且I/O速率得到大幅度提升。     

利用单片机I/O端口线模拟串行口通讯

介绍一种采用单片机I/O端口线模拟串行通讯的技术,用于多MCU系统中的串行通讯。该技术可以高效实现系统内的数据通讯,减少系统复杂度,有效提高系统稳定性、可靠性。     

计算机调速控制系统I/O通道故障检测

本在分析计算机调速控制系统的基本组成和工作原理的基础上，从基本数据流程控制入手，按功能作用分别对系统的输入输出控制信号进行了归类和分析。用89C51型8位单片机代替32位单片机，设计并开发了谊控制系统的I/O通道故障检测装置。为现场技术人员提供了快速、准确的故障检测和维修方法，保证了设备的可靠运行，提高了生产效率。     

Heuristic file sorted assignment algorithm of parallel I/O on cluster computing system

1INTRODUCTION Withthedevelopmentofcomputertechnolo gies,dataprocessing,transferringandstoringareadvancedgreatly.ButtheperformanceofI/Osub systemisnotimprovedaccordingly.SotheI/Osubsystembecomesabottleneckofthehighper formancecomputing[13].Theeffectivemethodofsolvingtheproblemreliesonsoftware,thatis,tostoreandaccessdatainparallelI/Oacrossmulti nodesofclusterintermsofsomefileallocatingstrategies[4].TheprofessionalpracticeprovesthatparallelI/Oisaneffectivemethodtoeliminatethebottleneck.T…     

采用CPLD器件扩充单片机I/O口

由于单片机I／O地址资源十分有限,硬件接口电路不应占用过多的I／O口,本文采用对数据总线译码的方法可以几乎不受限制的扩充I／O地址。同时利用CPLD器件的高密度性和可编程性可以提高硬件电路的集成性、可乘性及保密性。     

PMC诊断法维修数控机床的I/O故障PMC诊断法维修数控机床的I／O故障

由PMC控制的输入输出故障是数控机床运行过程中最常见的故障。阐述了数控机床PMC诊断中常见的四种途径的实施方法、注意事项,以期达到对于故障的快速诊断、高效排除的目的。     

基于动态混合分片机制的云存储系统I/O性能优化算法

为了解决云存储系统中存储I/O性能优化的问题,从数据分布的角度进行研究,建立了存储分片性能模型,并以此为基础给出了以I/O性能最优为目标的分片决策算法以及最优分片数的计算方法,提出了基于动态混合分片机制的数据分布算法(DADH).DHAH能充分考虑各存储节点和客户机的实际性能,动态地进行文件分片决策和最优分片数的计算,并且能根据存储节点的实际性能优化数据分布.实验结果表明:DADH较传统数据分布算法具有最优的I/O性能,并且算法性能提升效果在各种带宽下平均达到18%~44%.     

A hybrid storage technology for low power consumption and high I/O performance in an IPTV set-top box

A new method of prefetching data blocks from the NVCache to the page cache in main memory and cascading prefetching n-blocks from a hard disk to the NVCache together was proposed to reduce the spin-up frequency of a hybrid hard disk drive and thus enhance I/O performance. The proposed method consists of three steps: 1) Analyzing the pattern of read requests in block units; 2) Determining the number of blocks prefetched to the NVCache; 3) Replacing blocks in the NVCache according to the block replacement policy. The proposed method can reduce the latency time of a hybrid hard disk and optimize the power consumption of an IPTV set-top box. Experimental results show that the proposed method provides better average response time compared to an existing adaptive multistream prefetching (AMP) method by 25.17%. It also reduces by 20.83% the average power consumption over that of the existing external caching in energy saving storage system (EXCES) method.     

在单进程操作系统环境下实现磁盘并行I／O的安全方法

本文分析了在ＤＯＳ环境下进行实时多任务并行处理时，影响系统安全性的关键问题。结合具体应用，利用ＤＯＳ内核在等待输入输出时循环执行ＩＮＴ２８空闲调用这一特点，将后台程序作为ＩＮＴ２８中断服务程序，实现了后台Ｉ／Ｏ操作完全在ＤＯＳ控制下进行，从而保障了系统的安全性．     

Using the GPS observations to reconstruct the ionosphere three-dimensionally with an ionospheric data assimilation and analysis system (IDAAS)

Using an international reference ionosphere (IRI) model as a background ionosphere and applying the Kalman filter to update the state with observations, we develop an ionosphere data assimilation analysis system (IDAAS) to reconstruct a three-dimensional (3D) ionosphere with the GPS slant TEC and ionosonde data over east-south Asia. The preliminary results with the GPS data collected over east-south Asia on 30 June 2005 showed that inversed slant TEC has very good correlation with the observations both for the GPS sites being and not being involved in reconstruction. The inversed NmF2 and vertical TEC both demonstrate great improvement of agreement with those observed from ionosondes and TOPEX satellite independently.     

Microwave-assisted hydroxylation of benzene to phenol with H2O2 over FeSO4/SiO2

Hydroxyl radicals HO are generated under Fenton-like (Fe2++H2O2→HO-+OH-+Fe3+) catalytic conditions upon microwave irradiation. Liquid-phase direct catalytic oxidation of benzene to phenol was obtained using FeSO4 supported on silica gel as a solid catalyst and hydrogen peroxide as the oxidant. The effects of various parameters, such as the different solvents, the amount of solvent used, the amount of catalyst used, the reaction time, the reaction temperature and the amount of hydrogen peroxide used on the yield of phenol were studied to identify optimum reaction conditions. Conventionally heated reaction gives a phenol yield of 0.6%. A higher phenol yield of 13.9% with a selectivity of 100% is obtained when the reaction mixture was irradiated with microwave energy. It is concluded that microwave irradiation offers more effective control of energy input for hydroxyl radical generation that is appropriate for various synthetic reactions.     

不同钒载量V2O5/SiO2催化剂上异丁烷催化脱氢制异丁烯的研究

采用浸渍法制备了不同钒载量的V2O5/SiO2催化剂,并用XRD、FT-IR、TPR和微反活性评价等手段对催化剂表面钒物种的分散状态和异丁烷脱氢反应性能进行了研究。结果表明,当V2O5负载量低于8%时,催化剂表面主要为还原性能较好、单层分散的孤立与低聚合度的钒氧物种;当V2O5负载量大于8%时,催化剂表面开始形成还原性较差的高聚合度钒氧物种和V2O5晶体。异丁烷脱氢活性测试结果显示,V2O5最佳负载量为8%,此时异丁烷转化率可达34%,异丁烯选择性为95%。