Windows环境下相量测量系统性能分析

分析了电力系统实时监控系统对同步相量测量装置(PMU)在实时性、可靠性和精确性3个方面的要求,并以一套典型硬件平台为例,讨论了基于Windows系统的PMU的性能特点以及在实时性方面的不足,给出了描述PMU实时性的重要指标——发送延时。在相量计算中采用了递归离散傅里叶(DFT)算法,大大减小了计算量,提高了系统的实时性;分析了Windows系统下消息机制的根本缺陷,提出分别利用虚拟设备驱动(VxD)和多线程技术实现中断和查询2种软件运行机制的方法,并应用于PMU的原始数据处理与数据传输中。测试结果表明,该方法可以有效改进Windows环境下监测系统的实时性,能够满足系统实时运行的要求。     

宽调速细分自适应步进电动机驱动器研究

采用细分自适应的方法设计了一个具有8种细分状态并且能够随控制频率变化而细分自适应的步进电动机驱动器,试验结果证明:解决了步进电动机调速范围窄、运行过程中细分切换产生速度突变的问题。     

场发射示器矩阵寻址高压驱动电路的设计研究

提出了矩阵寻址方式的场发射驱动电路。设计出16级灰度显示的阴极驱动电路以及栅极驱动电路,并对其进行了性能仿真,仿真结果显示驱动电路性能优越。开发出与0.8μm标准CMOS工艺兼容的高压CMOS工艺,有效提高了驱动电路的集成度,并降低了生产成本。成功研制出用于场发射驱动电路输出端的100 V高低压电平转换电路,实验测得空载情况下电路的上升时间和下降时间分别为35,60 ns,能够满足高压驱动电路的频率要求。     

嵌入式Linux系统中字符设备驱动程序的开发

结合嵌入式开发板S3C2410F的模数转换驱动程序的开发，该文对Linux环境下交叉编译环境的建立，字符设备驱动程序的组成、实现、调试和发布方法进行了详细的论述。     

基于轮询差异检测和钩子捕获技术的屏幕变化捕捉的研究

从计算机图形化界面诞生起,屏幕共享便成为研究热点。人们一直在寻找一种方式既能减少数据的传输量又能使得用户可以流畅地观看被共享的屏幕．屏幕变化捕捉便是其中之一。在Windows平台下分析讨论轮询差异检测、钩子捕获,以及镜像驱动检测,阐述各种技术的实现原理。设计一款基于轮询差异检测和钩子捕获技术的屏幕变化捕捉系统,通过测试对象．对两种算法其捕获效率以及捕获效果进行对比分析。     

Combining cognitive and visual distraction: Less than the sum of its parts

Driver distraction has become a leading cause of motor-vehicle crashes. Although visual and cognitive distraction has been studied extensively, relatively little research has addressed their combined effects on drivers’ behavior. To fill this gap, a medium-fidelity simulator study examined the driver behavior before, during and after three types of distraction. Driving without distraction was compared to visual distraction, cognitive distraction, and combined visual and cognitive distraction. The results show that the visual and combined distraction both impaired vehicle control and hazard detection and resulted in frequent, long off-road glances. The combined distraction was less detrimental than visual distraction alone. Cognitive distraction made steering less smooth, but improved lane maintenance. All distractions caused gaze concentration and slow saccades when drivers looked at the roadway, and cognitive and combined distraction increased blink frequency. Steering neglect, under-compensation, and over-compensation were three typical steering failures that were differentially associated with the different distractions: steering neglect and over-compensation with visual distraction and under-compensation with cognitive distraction. Overall, visual distraction interferes with driving performance more than cognitive distraction, and visual distraction dominates the performance decrements during combined distraction. These results suggest that minimizing visual demand is particularly important in the design of in-vehicle systems and in the development of distraction countermeasures.     

Driver responses to differing urban work zone configurations

This study reports the results of a simulator-based assessment of driver response to two different urban highway work zone configurations. One configuration represented an existing design which was contrasted with a second configuration that presented a reduced taper length prototype work zone design. Twenty-one drivers navigated the two different work zones in two different conditions, one with and one without a lead vehicle; in this case a bus. Measures of driver speed, braking, travel path, and collision frequency were recorded. Drivers navigated significantly closer to the boundary of the work area in the reduced taper length design. This proximity effect was moderated by the significant interaction between lead vehicle and taper length and such interactive effects were also observed for driver speed at the end of the work zone and the number of collisions observed within the work zone itself. These results suggest that reduced taper length poses an increase in risk to both drivers and work zone personnel, primarily when driver anticipation is reduced by foreshortened viewing distances. Increase in such risk is to a degree offset by the reduction of overall exposure to the work zone that a foreshortened taper creates. The benefits and limitations to a simulation-based approach to the assessment and prediction of driver behavior in different work zone configurations are also discussed.     

一种基于SIMATICT—CPU的运动控制伺服系统设计

设计和论证了一种以西门子SIMATICT—CPU315T-2DP作为轴的运动控制器,以IM174作为通信模块连接伺服电机和控制器,控制伺服电机完成各种电机运动,以及多套伺服电机组成的电机群之间的同步运动和组合复杂运动的可行方案。经实践检验,这种方案简单易行,可以作为一般运动控制伺服系统设计的模板。     

基于光耦HCPL316J的大功率IGBT驱动电路研究

本文主要对逆变器等功率装置的IGBT驱动电路进行研究,从门极驱动电压、门极驱动电阻、驱动电路功率与IGBT的关系以及驱动保护等方面分析了驱动电路的设计。最后设计了以基于光电耦合器HCPL316J的驱动电路,计算了电路的参数。通过驱动实验和短路保护实验,验证了设计的正确性。