RTLPoWer：一个实时动态电压调节低功耗系统

功耗问题是计算机系统发展亟待解决的问题,硬件和软件在解决功耗问题上都有重要的作用.尽管有许多工具可用于低功耗硬件的开发,但支持软件技术开发的低功耗工具并不多见.我们基于ARM的指令集开发了一个实时动态电压调节低功耗系统RTLPower.RTLPower综合了编译指导的动态电压调节和程序的性能功耗模拟,该系统能够有效支持编译指导的动态电压调节技术的研究开发.     

反馈策略的系统多任务低功耗调度算法研究

嵌人式系统的低功耗调度算法是嵌入式系统低功耗技术的重要研究方向,在动态电压调节技术的基础上,提出了一种基于反馈控制策略的嵌入式系统多任务低功耗调度算法,给出了该算法的静态调度策略及动态调度策略;在此基础上给出了算法调度实例,用Vc编写软件仿真对比了该算法与其它两种算法的低功耗特性;结果表明,基于反馈策略的嵌入式系统多任务低功耗调度算法对降低功耗作用显著.同时,通过对比得出不同算法的能量消耗在系统的负载小于0.4时能耗变化平稳,变化不大,当系统的负载大于0.4时各种调度算法的能耗都在增加,试验表明不同调度算法下嵌人式系统所消耗的能量与该系统的负载大小直接相关.     

动态电压调节技术在高性能计算领域的能效研究

功耗问题是未来高性能计算机系统性能提高面临的最突出问题之一,本文调查典型的低功耗技术动态电压调节应用于高性能计算机系统的有效性。建立了动态电压调节技术在高性能计算领域的能耗模型,提出了程序运行时钟能耗和真实能耗的概念。在三种典型的计算机系统上,使用智能功率仪表测试使用动态电压调节技术后的系统能耗,说明了动态电压调节技术在高性能计算领域节能降耗的有效性。     

多核系统中基于Global EDF 的在线节能实时调度算法

随着多核系统能耗问题日益突出,在满足时间约束条件下降低系统能耗成为多核实时节能调度研究中亟待解决的问题之一.现有研究成果基于事先已知实时任务属性的假设,而实际应用中,只有当任务到达之后才能够获得其属性.为此,针对一般任务模型,不基于任何先验知识提出一种多核系统中基于Global EDF在线节能硬实时任务调度算法,通过引入速度调节因子,利用松弛时间,结合动态功耗管理和动态电压/频率调节技术,降低多核系统中任务的执行速度,达到实时约束与能耗节余之间的合理折衷.所提出的算法仅在上下文切换和任务完成时进行动态电压/频率调节,计算复杂度小,易于在实时操作系统中实现.实验结果表明,该算法适用于不同类型的片上动态电压/频率调节技术,节能效果始终优于Global EDF算法,最多可节能15％～20％,最少可节能5％～10％.     

无线传感器网络混合任务的系统级低功耗实时调度算法研究

现有的无线传感器网络节能研究主要集中在无线通信上面,针对传感器节点CPU节能的研究还不够充分.本文以多任务、多跳网络传输的实时无线传感器网络为研究对象,从节点的调度分析出发,在保证其实时性的前提下,结合动态电压调节技术,提出两个低功耗实时调度算法:(1)基于任务最坏执行时间来计算任务CPU速度的静态低功耗调度算法;(2)将任务在实际执行过程中产生的空闲时间,分配给余下将要执行的任务,进一步调整其电压等级,即动态低功耗调度算法.仿真实验结果表明,本文提出的算法能够有效降低节点CPU能耗.     

基于DPM和DVS的双效节能调度算法

对于电池供电系统,如何降低功耗已成为系统设计中的一个关键问题.通过对系统功耗组成及任务调度策略进行深入分析,提出一种动态电压调节(DVS)和动态功率管理(DPM)相结合的双效节能调节算法DVS-PM.DPM动态管理处理器及外围模块在工作模式和低功耗模式之间切换,DVS在保证系统实时性前提下,实现系统运行在功耗最低的最佳工作点,达到更好的节能效果.实验结果表明,该节能调度算法能大幅减少系统能量消耗,与不采用节能算法相比,节能55.4%.     

基于动态电压调节技术的低功耗调度算法研究

基于动态电压调节技术的低功耗调度算法的研究是嵌入式系统软件低功耗技术的研究重点。通过研究以最大空闲时间安排任务优先级的低功耗调度算法,对UCOSII嵌入式实时操作系统的内核进行了改进,并在实际的硬件环境上进行实验,实验结果显示改进算法的内核执行与原内核相同的音频任务时降低了系统的功耗。     

DVS技术中切换时间间隔分配的方法

动态电压调节(DVS)被认为是低功耗设计中最有效的一项技术.但在应用动态电压调节技术的过程中,需要考虑许多细节问题,才能使模型真正接近实际系统,从而在分析中得到较优的结果.本文正是在DVS中考虑到了电压切换产生的时延和能耗,以一种新的模型来分析功耗、改进算法,最终达到降低功耗的目的.文中提出了分配切换时间间隔的一种依据.     

基于混合任务的系统级低功耗实时调度算法及其在馈线远方终端中的应用

在保证实时性的前提下,研究了馈线远方终端的系统级低功耗设计方法．在馈线远方终端中采 用主从CPU 的硬件结构,对主CPU 进行任务划分和实时性分析;并结合动态电压调节技术,设计了基于混合 任务的静态、动态低功耗调度算法．仿真实验表明,该方法能够有效降低远方终端的功耗．     

基于软实时多处理器系统的动态低功耗算法

结合DVS技术和(m,k)-firm模型，提出一个保证完成率、适用于软实时多电压多处理器系统中有依赖关系任务集的动态低功耗算法VAP_DY。该算法权衡应用的性能需求、执行时间的不确定性和系统对合理执行失败的容忍来动态调整每个处理器运行时的供电电压,以降低多处理器系统的总功耗。分析和实验结果表明，VAP_DY能够在保证时间和完成率约束的条件下有效降低系统功耗。     

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