基于云计算的蒙特卡罗模拟研究

为了提高蒙特卡罗模拟算法的运算效率和精确度,需建立一个能满足高精确度、高效率、易扩展、易使用的计算环境。本文根据云计算可弹性增加计算节点的特点,将Symphony DE并行软件搭建在本地私有云环境下,运用在Excel中的编程实现蒙特卡罗模拟,通过增加计算节点数目对比运算效率与计算精度。结果表明:随着计算节点数的增加,运算效率大大提高,计算结果更加精确。     

一种防御差分功耗分析的ECC同种映射模型

现有的公钥密码研究大多是以增加椭圆曲线密码体制(ECC)的冗余操作来抵御差分功耗分析(DPA)攻击,但会降低ECC的运行效率,从而影响ECC在运算环境受限的密码设备中的使用。为此,以增强ECC的功耗安全和提高计算效率为目标,基于椭圆曲线同种映射理论,建立椭圆曲线等价变换模型,并设计一种能防御DPA攻击ECC的安全方法,通过变换椭圆曲线点乘运算的表现形式,消除点乘运算与泄漏的功耗信息的相关性,从而防御DPA攻击ECC。效率及安全性评估结果表明,该方法没有增加ECC的额外计算开销,且能够防御DPA攻击。     

分子动力学在小型SMP集群中的并行计算

为提高分子动力学的模拟运算效率,在Linux环境下以MPICH技术构建的小型SMP集群系统上,对模拟体系采用改进的原子分解算法进行并行计算.将要模拟的原子平均分配给各个计算节点进行计算,节点间通过MPI进行通信.对进程间的接收和发送进行捆绑操作并采取非阻塞通信取代原有的阻塞通信,从而避免了死锁情况.实验结果表明:优化后的并行算法可以有效地利用计算机资源,提高运算效率,解决了实际测试中出现的死锁问题,在该集群系统上获得3倍以上的加速比.     

一种基于给定目标节点的个性化PageRank算法设计

以往衡量图网络节点重要性时,多基于给定源节点,计算该节点到其余目标节点的个性化PageRank值并推出重要目标节点,运算效率低且存储量大。基于此,提出了一种基于给定目标节点的个性化PageRank算法(TPPR),该算法结合本地更新与优先队列算法,通过计算从所有源节点到给定目标节点的个性化PageRank值来推出重要源节点,相较于传统算法运算精度更高,运行时间大幅减少。     

基于GPU的图形学加速算法在离散元法中的应用

颗粒离散元法是一种广泛应用于研究颗粒物料力学行为的数值模拟方法,而计算效率是制约其发展和应用的主要因素之一。通过Pro/E软件建立了料斗模型,利用Stream DEM软件对料斗的颗粒充填过程进行离散元法模拟研究,并对基于CPU和GPU加速算法的运算过程和结果进行对比。结果表明,基于GPU的计算机图形学加速算法可大幅提高颗粒离散元法模拟过程的运算效率。当填充颗粒数量达到13万时,其运算效率比基于CPU的运算效率提高了10倍以上。     

Office Excel软件在办公自动化中的应用

随着互联网的普及,各行各业逐渐都实现了办公自动化,Office Excel软件是一款重要的办公软件,其通过表格形式呈现各种数据,并且提供简单的计算处理功能,在实际应用中,极大地提高了办公效率和办公水平,为人们的数据分析和处理提供了便利.本文简要介绍了Office Excel软件和其应用特性,分析了Office Excel软件在办公自动化中的应用.     

基于Winograd卷积的并行深度卷积神经网络优化算法

针对并行深度卷积神经网络算法在大数据环境下存在冗余特征计算过多、卷积运算性能不足和参数并行化合并效率低等问题，提出了基于Winograd卷积的并行深度卷积神经网络优化算法。首先，该算法提出基于余弦相似度与归一化互信息的特征过滤策略，通过先筛选后融合的方式消除了通道间对于冗余特征的计算，以此解决了冗余特征计算过多的问题；然后，结合MapReduce提出了并行Winograd卷积策略，通过使用并行化Winograd卷积运算替换传统卷积运算的方式来提升卷积运算的性能，以此解决了卷积运算性能不足的问题；最后，提出基于任务迁移的负载均衡策略，通过动态负载迁移的方式来均衡集群中各节点之间的负载，降低了集群总体的平均反应时长，以此解决了参数并行化合并效率低的问题。实验表明，WP-DCNN算法显著降低了DCNN在大数据环境下的训练代价，而且对并行DCNN的训练效率也有大幅提升。     

迭代算法在Excel中的实现探究

迭代算法是指利用计算机反复执行同一个模式的运算,并结合变量因素,实现对最终值的明确。迭代算法是一种线性的函数计算模式,基于不同的运算方式,可以将其分为雅克比迭代、二分法迭代、牛顿迭代等,基于此方程在Excel中的应用,不需要软件便可直观展现计算最终数值。笔者基于迭代算法在Excel中的应用,阐述了迭代算法应用的要点和原理,并对不同迭代算法的应用进行了分析,具有重要借鉴价值。     

一种新型集成运放线性电路的分析方法*

针对多个运放构成的复杂线性电路的已有分析方法运算效率不高的缺点,提出利用节点电压法,选取反相（同相）输入节点列写节点电压方程的分析方法。论文详述该方法的原理与典型应用,最后用仿真软件进行验证。与已有方法相比,该方法提高了求解由多个运放构成的复杂线性电路的运算效率。同时方法可靠、简便、易行。     

结构体对象的赋值运算方法研究

随着计算机技术的飞速发展,软件的覆盖面越来越广,软件质量的保证成为了一个越来越重要的环节。结构体在程序设计语音中被广泛使用,在静态代码检测的时,对结构体变量进行区间运算的时候不能给出其明确的区间信息,会对其相关运算的判断精度造成影响,本文介绍了一种对结构体赋值运算的区间计算方法。首先,从抽象语法树中识别结构体变量节点,其次为他们建立抽象内存模型,再次根据控制流图节点在其进行赋值运算的时候对它的子成员变量进行运算。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate