Queueing analysis of a server node in transaction processing middleware systems

Quantitative performance modeling of complex information systems is of immense importance for designing enterprise e-business infrastructures and applications. In this paper, we present a traffic model of a server node in a typical transaction processing middleware system as well as a quantitative framework to model and analyze its performance. A multi-class open queueing network model is presented in which multi-class jobs are admitted to a number of server processes sharing hardware resources including the CPU and the disk. We have developed a viable approximation method, which decomposes the dependent components into their independent counterparts while preserving their relevant characteristics. We have conducted queueing-theoretic delay analyses and verified the approach using simulation. Results demonstrate the strength of our approach in predicting delays, elapsed times and other system performance measures.     

A Rectangular Finite Volume Element Method for a Semilinear Elliptic Equation

In this paper we extend the idea of interpolated coefficients for semilinear problems to the finite volume element method based on rectangular partition. At first we introduce bilinear finite volume element method with interpolated coefficients for a boundary value problem of semilinear elliptic equation. Next we derive convergence estimate in H ¹-norm and superconvergence of derivative. Finally an example is given to illustrate the effectiveness of the proposed method. This work is supported by Program for New Century Excellent Talents in University of China State Education Ministry, National Science Foundation of China, the National Basic Research Program under the Grant (2005CB321703), the key project of China State Education Ministry (204098), Scientific Research Fund of Hunan Provincial Education Department, China Postdoctoral Science Foundation (No. 20060390894) and China Postdoctoral Science Foundation (No. 20060390894).     

Applications of thick Sacrificial-Layer of zinc in LIGA process

Sacrificial-Layer technology is widely used in the microfabrication field of SLIGA. In this paper, thick sacrificial layers of zinc techniques are studied. A movable structure with aspect ratio of 25 has been fabricated by using zinc sacrificial layer through LIGA technique. Compared with conventional metal sacrificial layers of titanium or copper, the thickness of zinc layer can grow up to more than 10 μm. The adhesion of different seed layers and the physiognomy of sacrificial layer are also focused in this paper.     

镱应力传感器的制作与应用

在数十MPa~2 GPa范围内的动态应力测量中,镱传感器的压阻系数高,可灵活埋置于待测材料中使用。该种传感器对研究冲击波在岩石、土壤、液体介质和结构材料中的传播与衰减规律显示出了优异性能。对国内外镱应力传感器研制工作进行了总结,介绍了该类传感器在爆炸、射弹侵彻、高速碰撞以及高能激光辐照等方面的应用,并指出了该种传感器存在的一些问题。     

圆锥裁剪BLOB的视频目标检测方法

真实场景的视频目标检测需要消除阴影、反射和鬼影等噪声的影响,以检测出运动目标和静止目标.为了实现系统性的视频目标检测,提出一种自适应圆锥裁剪联通块(TC-BLOB)榆测方法.基于BLOB知识,将3D颜色空间变换为"夹角-模差"2D空间后,定义一套圆锥裁剪规则划分出阴影BLOB和反射BLOB;再以一种持久化记忆PM方法判别出鬼影BLOB;最后改进双背景模型检测出静止目标和运动目标.采用不同环境视频进行实验的结果表明,文中方法足有效的,并有独立于后续跟踪的优点.     

对操作系统内核动态扩展的研究

操作系统内核动态扩展有利于核心空间的利用和系统性能,被现代操作系统普遍采用,但面临的关键问题是扩展模块对系统内核安全性、可靠性的影响.通过分析主流操作系统Linux、Windows、Mac OS X的内核模块按需加载机制及其安全、可靠性措施,指出这些操作系统都存在对内核模块安全控制的不足之处.从设计的角度对内核扩展机制的安全性和可靠性提出几点建议,并介绍了所进行的研发工作,有助于弥补内核扩展安全控制的缺陷.     

基于DM6437的运动目标检测系统

采用非参数化的核密度估计完成背景减法,设计了基于高端数字媒体处理器KM6437的实时运动目标检测系统.提出了一种有效的背景更新策略,使得背景的更新更加可靠,提高了检测的精确度.实验表明该系统能够对目标进行比较实时和准确的检测.     

基于局部子图匹配的SLAM 方法

针对现有的SLAM 解决方法在机器人被“绑架”时失效的问题,提出了基于局部子图匹配的方法．该 方法对现有的SLAM 解决构架进行了改进,提出交点最优匹配的特征相关算法,并且将奇异值分解方法引入机器人 定位．最后,在结构化环境下将本方法和基于扩展卡尔曼滤波器的方法进行比较,讨论了基于局部子图匹配的方法 在结构化环境中解决机器人“绑架”问题的有效性和可行性．     

基于ARM和MiniGUI的呼气式酒精测试仪研究

设计了一种以ARM7微控制器LPC2210为核心的燃料电池型呼气式酒精测试仪;该仪器在LPC2210上移植嵌入式操作系统uClinux,利用燃料电池传感器的输出电压与酒精浓度的相关性,通过采集燃料电池传感器中酒精气体反应产生的模拟信号计算出酒精浓度;详细介绍了燃料电池传感器的电化学原理,及在ARM-Linux嵌入式操作系统环境下,利用轻量级的图形用户界面支持系统MiniGUI进行软件界面开发的方法,提高了人机交互友好性和易操作性;实验表明,该酒精测试仪具有稳定性好、精度高、抗干扰性强的明显优点。