支持多重循环软件流水的循环控制机制

ＩＬＳＰ－内外层交替执行的多重循环的软件流水算法是对多重循环进行优化的有效方法。为了保证ＩＬＳＰ算法具有良好的时间效益和空间效益，就必须有一套支持这个算法的行之有效的多重循环软件流水机制。文中将比较详细地介绍一套控制机制。它与多重循环优化编译器相配合，可以有效地支持多重循环的软件流水，并且可以保证ＩＬＳＰ算法具有较高的加速比和较低的空间代价。     

软件流水中的一种数据调度算法

文章第1节对软件流水下多重循环中数据元素的调度进行了分析,着重讨论了用地址计数器完成简单地址运算的意义、ILSP(interlaced inner and outer loop software pipelining)算法的基本思想及其在此基础上分析了软件流水下多重循环中数据元素的调度特点；第2节进一步探讨了为完成调度而寻找地址控制信息序列的一般方法；第3、4节则分别讨论了用求得的地址控制信息序列控制地址计数器对数据元素的访问和将地址控制信息序列化简为精简地址控制信息序列的步骤；最后两节分别是实验结果和结     

基于VLIW的数据通路分配算法

体系结构相关的优化编译模型需要考虑底层硬件的特性。该文针对目标机具有软件可以控制数据通路的特点提出了一个数据通路分配算法,该算法综合考虑了两个关键因素——子通路和通路操作,从而减小了分配结果对并行性的影响。该算法不仅可以用来解决数据通路分配问题,而且可作为解决多重资源分配问题的一个参考方法。     

多重循环的软件流水技术

为了解决多重循环的指令级并行编译问题，本文提出了反刍方法，以一种新的思维方式处理多重循环，将其视为一个程序流整体，有效地开发了多重循环的并行度．另外，本文还给出了实现反刍方法的基本步骤以及相应的硬件支持．最后，通过一些初步实验的结果验证了本算法的有效性，并讨论了其时间和空间效益，分析了其主要特点.     

基于P2P的VOD系统中的数据传输分配算法

在基于P2P的VOD系统中,流媒体数据的传输模式一般是多对一的,数据传输任务在多个源节点间的分配是系统设计的一个核心问题。在保证流媒体连续播放条件下,给出了一个以缓冲延迟为优化目标的最优化分配算法ODTAP2P,并对算法的最优性给出了数学证明,并通过实例验证了算法的有效性。该算法在计算复杂性与同类算法相同的前提下更适合于实际环境下应用。     

神经网络的具有自适应动量和步长的伪牛顿算法

以单隐层的３层前向神经网络为基础，由自适应ＢＰ算法和牛顿优化算法导出了自适应步长和动量解耦的伪牛顿算法（ＱＮＡＤＳＭ）．该算法计算量小，收敛速度快．文中还给出了该算法的收敛性证明、算法的仿真结果及其它算法的比较结果，并对网络的训练及该算法的特点作了进一步的讨论．仿真结果表明ＱＮＡＤＳＭ算法是一种有效的工程实用算法．     

一种分布式共享存储系统的线程分配算法

讨论了软件实现了多线程ＤＳＭ 的通信开销和线程分配问题,给出了一种基于线程关系图的调度模型,并在此基础上提出了一种基于迭代的线程分配算法,通过大量的线程关系图对算法进行了评价,并且在一个软件ＤＳＭ系统中实现了该算法,同时给出了算法的评价结果和应用程序的性能数据。     

一类非规则并行应用问题的通信集生成算法

非规则计算是大规模并行应用中普遍存在和影响效率的关键问题.在基于分布式内存的数据并行范例中,如何针对非规则数组引用,有效地生成本地内存访问序列和通信集,是并行编译生成SPMD结点程序所必须解决的重要问题.文中针对两重嵌套循环中,下一层循环边界是上一层循环变量的线性或非线性函数,数组下标是两层循环变量的非线性函数这样一类包含非规则数组引用的并行应用问题,提出了一种在编译时生成通信集的代数算法.并且针对cyclic(k)数据分布和线性对齐模板,借助整数格概念,给出了编译时全局地址和本地地址之间的转换方法.文中还给出了相应的经过通信优化的SPMD结点程序.最后通过实例验证了算法的正确性.该算法的意义在于避免了传统Inspector/Executor非规则计算模型中的Inspector阶段,从而节省了运行时Inspector阶段通过穷举下标生成通信集的巨大开销.     

PSO算法粒子运动轨迹稳定收敛条件分析

由于随机量的作用,粒子群优化算法（ＰＳＯ）中粒子的位置迭代是一个非线性动态离散过程,单个粒子在随机量影响下的运动方程可转换为一个二阶变系数非齐次方程．为此,利用Ｌｙａｐｕｎｏｖ稳定定理对该方程的稳定性作了深入研究,分析得到了使粒子运动稳定收敛的惯性权重和随机参数取值条件．实验结果表明,按照所得到的条件选择参数取值,能使粒子运动轨迹快速稳定收敛．该结果有助于实际应用中ＰＳＯ 算法参数的选择和调整．     

采用两级软件流水技术的VLIW优化编译器

本文首先提出一种能够充分开发循环程序指令级细粒度并行性的编译技术——两级软件流水,该技术基于URPR软件流水算法,把资源分配和代码优化有机地结合起来;然后叙述采用两级软件流水的VLIW优化编译器;最后给出一个FFT内层循环编译过程的实例及初步实验结果.     

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