Resource contention in shared-memory multiprocessors: A parameterized performance degradation model

A standard metric conventionally employed to compare the performance of different multiprocessor systems is speedup. Although providing a measure of the improvement in execution speed achievable on a system, this metric does not yield any insight into the factors responsible for limiting the potential improvement in speed. This paper studies the performance degradation in shared-memory multiprocessors as a result of contention for shared-memory resources. A replicate workload framework with a flexible mechanism for workload specification is proposed for measuring performance. Two normalized performance metrics—efficiency and overhead factor—are introduced to quantify the factors limiting performance and facilitate comparison across architectures. Finally, the proposed model is employed to measure and compare the performance of three contemporary shared-memory systems, with special emphasis on the newly released BBN Butterfly-II (TC2000), currently undergoing Beta test.     

考虑水头影响的梯级水电系统优化调度算法研究

提出一种基于Ｌａｇｒａｎｇｉａｎ松驰技术的梯级水电系统优化调度算法，能够综合处理离散运行区间、最小启停机时间等离散约束、水库间的水力耦合网络约束以及水头影响。基于实际系统数据的数值验证表明了本算法的有效性和实用性。     

低压配电系统无功集中补偿装置的应用

结合攀成钢炼铁厂3#高炉槽下低压配电室和循环水泵站低压供电系统对无功集中补偿装置的应用,阐述了无功补偿对输变电设备的作用,可提高运行技术指标,取得良好的经济效益。     

Al-6.1Zn-2.6Mg-1.6Cu 铝合金的回归再时效热处理

The effects of the retrogression temperature and time of retrogression and re-aging heat treatment(RRA) on the hardness and electrical conductivity of Al-6.1Zn-2.6Mg-1.6Cu aluminum alloy were studied. Samples were pre-aged at 120℃ for 24h as the first-stage treatment. Then, retrogression was performed at a temperature range of 170～250℃ for times of between 1min and 180min, followed by re-aging at 120℃ for 24h. Hardness (H) and electrical conductivity (EC) measurements were used to characterize the samples after RRA treatment. Analysis of the results shows: (1)The re-aging treatment at 120℃ for 24 h increases both H and EC of the retrogressed alloy in the RRA process;(2) RRA with retrogression at higher than 200℃ result in EC higher than that of peak-aged, but H lower; The change of H and EC with respect to retrogression temperature (T) and time (t) can be seen as functions of H (t) = H0 A1e(-t/s) ,EC(t) =A(1-e(-k·(t-Xc)));(3) RRA treatments with retrogression at 190℃ for 4～30min result in H and EC which are both higher than those of the peak-aged temper, and retrogression at 190℃for 30min is the industrial application that yields H of 190 HV and EC of 33.5%IACS.     

秋季太湖叶绿素a浓度荧光反演研究

基于2007年11~12月太湖全湖实测水质参数和光谱数据,首先利用高斯方程对遥感反射率进行过滤分解,找出叶绿素a(chl\|a)吸收峰675 nm以后的荧光反射峰(Fluorescence Peak:FP),再以662 nm处的反射率为基准,采用归一化荧光高度法进行叶绿素a浓度(C chl-a)反演,得到chl-a反演模型。基于高斯分解获取的chl-a的荧光反射峰值R(FP)与662 nm处的反射率R (662)比值［R(FP)/R(662)］与C chl-a之间存在显著的相关性,该模型为秋季太湖水体C chl-a的最佳反演模型。在高悬浮泥沙条件下,该模型能够较好地表示出叶绿素荧光高度与叶绿素浓度之间的关系,为C chl-a反演提供新的方法和依据,并为传感器敏感波段的选取和设置提供参考。     

医用漏电流自动检测仪的研制

本文阐述了医用电气设备安全检测的重要性,开发研制了含GB9706．1国家标准的医用漏电流自动检测仪,分析了医用电气安全检测标准,介绍了医用漏电流自动检测仪的系统结构,编制了数据采集、处理、存储、键盘控制及LCD显示的应用程序：医用漏电流自动检测仪的测量过程采用继电器组控制,使用方便、测量精确;同时与GB9706．1中标准容许值进行比较,显示是否通过,还可以进行报警。     

使用Visual C++实现多媒体电子出版物中的矢量电子地图

该文介绍在基于光盘的多媒体电子出版物中实现矢量电子地图的关键技术。使用VisualC＋＋和面向对象的方法实现了一个矢量电子地图引擎。     

UML建模与动态模拟测试

系统应用软件都具有实时性强、复杂性高的特点。软件系统的复杂性决定了模型本身的复杂履。为检查模型之间的一致性和模型的完备性,该文根据ＵＭＬ１．１规范,通过一个实例详细描述了如何建立一个规范和实用的模型,并提出一种基于ＵＭＬ模型的动态模拟测试方法。     

一种基于移动Agent的Ad Hoc可信网络架构

ad hoc网络是一组具有路由和转发功能的移动节点组成的一个多跳的临时性自治系统,是一种无中心的无线网络,现有的安全策略都是从某一方面提出改进方法;基于系统论思想方法,提出了一种基于移动Agent 的ad hoc可信网络架构,并进行了初步分析.