基于LXI总线的多通道振动信号测试系统设计

针对某些大型复杂装备的振动信号采集需求,测控场景需对上百通道的振动信号实现同步测量;而单一采集仪器很难满足百道测试需求,因此,文章研制了一种可扩展的多通道振动信号采集与分析系统;该系统采用LXI总线架构,其主控计算机与设备和设备间均采用LAN进行数据通信;振动测量模块采用了大动态范围数据采集技术,且主控系统软件采用分布式数据管理模式;最终,主控计算机以仪器驱动函数方式通过通信协议合理调控采集模块参数,并通过综合数据分析得到振动信号的故障诊断结果;通过对某型高速列车的轴箱轴承进行振动信号采集与数据分析,得到某一轴承出现了故障,验证了所设计测试系统的有效性。     

基于LabVIEW静压气体轴承性能检测装置的测控软件设计

采用LabVIEW设计了静压气体轴性能检测装置的测控软件.上位机软件通过串口与下位机进行指令传送和数据交换,控制检测装置运行,接收由AVR单片机采集的气体压力传感器、测力传感器和位移传感器的实验数据,同时对数据进行分析计算并实时显示和自动保存.实验结果表明,系统较好地实现了人机交互,自动化程度高、工作稳定性强、可操作性高.     

基于CAN总线的轴承疲劳寿命网络监控系统

介绍了基于CAN总线技术的轴承疲劳寿命网络监控系统,给出了系统的组成和结构,并对系统功能及软件实现方法进行了讨论。该系统利用计算机技术和自动检测技术对轴承进行在线监测;通过采集轴承的振动信号和温度信号获得大量数据,利用这些数据采用时域和频域相结合的方法,对轴承进行故障诊断。这种方法在生产现场应用以后,改变了轴承波劳寿命试验以往靠人工察看轴承温度和凭人耳听觉来判断轴承疲劳点出现的试验状况,为轴承生产提供了更加准确的数据,使轴承疲劳寿命试验水平大大提高。     

基于相关性原理起重机负载电机监测系统设计

对起重机负载电机进行了研究,采用西门子公司的S7-200 SMART PLC采集负载电机的机械振动信号,通过工业Wi-Fi无线模块以无线数据包的形式将采集的数据汇总到上位机LabVIEW监测平台;上位机的LabVIEW监测平台对电动机振动信号进行相关性和频谱分析,将实时振动数据频谱信号和已知常见负载电机的轴承外圈故障、轴承内环故障和滚子故障3种典型的故障状态频谱信号进行相关性运算,得到实时信号与已知状态的相关系数;提出了以相关系数作为故障诊断判定阈值的方法进行故障诊断,实现了对起重机状态进行监测以及监控信息发布。     

一种基于单片机的多位LED显示系统的设计

结合HS型滑动轴承实验台测控系统的具体实例,提出了一种基于51系列单片机利用LED进行实时数据显示系统的设计方案及其实现。介绍了基于单片机的LED显示系统的开发与应用,详细介绍了单片机系统及LED显示器的两种显示方式,软件部分介绍了数据显示程序和选择按钮计数程序。     

WCDMA高速上行变速率数据业务传输技术研究

论文分析了3GWCDMA系统使用较高传输速率支持上行变速率业务传输的接入约束模型,并利用该模型提出了一种上行方向支持WWW浏览业务的传输方案,给出了支持变速率传输的传输格式设计方案和接入控制规则,并仿真了不同可用系统负载情况下传输速率分布情况和系统拥塞概率。     

航空发动机轴承试验机测控系统的设计

为了分析新型材料航空发动机轴承的失效原因并提高轴承的使用寿命和可靠性,研制了一台能够模拟航空发动机工况的轴承疲劳试验机,设计了基于西门子S7-1500PLC的远程测控系统.测控系统通过PLC控制模块、驱动器和变频器等,实现了动力系统、润滑系统和加载系统的控制和试验载荷谱线的自动运行.试验主参数信号通过高速高性能模拟量A/D模块进行采集,并通过以太网传输至上位机.上位机软件对数据进行实时处理、存储和绘制曲线.通过试验验证,所设计的轴承试验机测控系统设计合理、运行可靠,为航空发动机轴承寿命研究和性能试验提供了基础平台和数据支撑.     

Hierarchical data management for structural analysis

The use of formal data bases management systems is becoming increasingly necessary in computer programs for structural engineering. This paper briefly reviews data base requirements and the organization of integrated computer program networks and identifies a need for hierarchical data base management in computer programs for structural analysis. The nature of the data hierarchy is illustrated with reference to a building that has been analyzed by using substructure techniques. The organization and features of the hiearchical data base manager STRATA are then described. STRATA has been developed specifically for use in structural analysis.     

Computer mouse use and cumulative trauma disorders of the upper extremities

The computer mouse is now present in virtually every office environment because of the recent adoption of the graphical user interface. However, Karlqvist et al. (1994) pointed out that there still remains a paucity of work on the musculoskeletal problems associated specifically with computer mouse use. Likewise, there have been no published data on the magnitude of upper extremity musculoskeletal disorders associated with computer mouse use. In order to ascertain this magnitude, claims data from the Liberty Mutual Group were reviewed for the years 1986 to 1993, inclusive. Count, total cost and average cost per claim for all claims associated with computer use and computer mouse use were determined for the years in question. It was concluded that although there are few claims related to computer mouse use, it appears to be a growing problem, and therefore, perhaps, deserves more research and intervention attention. However, the present magnitude is less than for other musculoskeletal disorders.     

Relationship between self-report and log data estimates of information system usage

Self-report estimates of frequency and duration of computer use are used extensively in research related to computer and information systems acceptance. Despite concerns that self-report estimates are inferior to computer log data there is a paucity of research investigating the relationship between self-report and log data measures of computer use. The present study compared self-report estimates and six months of electronic log data for 62 health care workers using a new Community Services Information System. There were moderate to strong correlations between the self-report and electronic log estimates of frequency and duration of system use. Self-report estimates were relatively accurate in that they were quite similar in magnitude to log data values. The merits of combinations of frequency and duration data (composites) were also assessed.     

数据库安全技术研究

数据库系统作为计算机信息系统的重要组成部分,数据库文件作为信息的聚集体,担负着存储和管理数据信息的任务,其安全性将是信息安全的重中之重。本文主要探讨了数据库系统面临的安全问题,并提出了一些建议。     

粗糙集理论在滚动轴承故障诊断中的应用

粗糙集是一种软计算方法,它不需要任何先验知识和理论推导,仅依赖于原始数据,从数据中发现潜在规律和隐含规则,其核心任务是数据约简,得到最简决策规则。文章基于粗糙集理论的可辨识矩阵算法,对滚动轴承故障信息表进行属性约简和属性值约简,得到了精简的诊断规则,从而方便了信息的机器处理,也为基于规则的滚动轴承智能故障诊断系统提供了一种更为简单的知识库自动构造方法。     

基于单片机C8051F的智能温控系统的设计与实现

随着自动化水平的不断提高,工业现场对温度的控制越来越高,设计了一种适用于现代工业现场的实时高精度温度监控系统;采用单片机C8051F020和PC机相结合,具有数据采集、数据显示、数据通信及数据存储等功能,通过RS485总线和上位机相连,上位机可以通过软件对系统进行设置和控制,系统同时通过液晶模块实时显示监测到的温度和万年历;试验证明,本系统具有一定的实时高精度性能,有着很强的推广价值。     

The dual nature of prior computer experience: More is not necessarily better for technology acceptance

It is often presumed that individuals with greater computer experience will easily adopt new or updated replacements of existing information technology. To examine this assumption, this study reviews prior computer experience research, identifies two key dimensions of computer experience i.e. computer use and computer proficiency and evaluates their effects individually. Analysis of survey data from 737 respondents using structural equation modeling indicates that each dimension had differential effects on behavioral intentions to use a newly introduced internet-based technology with computer use having curvilinear effects on adoption intentions. Implications for research and practice are discussed.     

试析计算机数据库的备份及恢复技术

国内科学技术的不断发展促进了计算机技术的推广运用,很多先进的计算机系统与设备正推广到企业中使用。而在计算机设备数据存储量不断增大的同时,对数据安全进行保护则显得格外重要。因而,用户在使用计算机时要选择相应的数据库备份及恢复技术,以保证各项数据的安全使用。     

A world-wide web service for calculating approximate AMBER CC and CN bond stretching and torsional parameters

A computer program implementing linear interpolation for the purpose of calculating approximate CC and CN bond stretching and twofold torsional parameters for the AMBER force fields has been constructed. The computer program is based on published data from the Kollman group, and the method has been extended to enable the use of π-bond orders for parameter calculation. The computer program is available for use through a user-friendly World-Wide Web page.     

利用动量轮测试气浮台干扰力矩的新方法

测量气浮台干扰力矩是气浮台参数标定的需要,也是气浮台动力学仿真试验的一项重要前期工作;为此提出了一种用于实测在卫星全物理仿真中的气浮台干扰力矩的新方法,在由单片机和控制计算机组成的测试系统中,根据动量矩定理,利用动量轮的启动加速特性测定气浮台的干扰力矩;通过单通道全物理仿真实验表明,该方法误差较小,只需利用动量轮,因而是气浮台试验中一种简单实用的干扰力矩测试方法;此测试方法稍作推广也可应用于测量气浮台和其它复杂物体的转动惯量。     

医院计算机安全主动防御技术探讨

随着计算机网络技术的发展,其在医院得到了广泛地应用,尤其是随着大数据时代的到来,医院计算机网络的使用有效地实现了患者信息、治疗案例等数据的联网管理,已经成为医院信息化的重要组成部分,但是医院计算机网络安全面临的问题日益突出。本文分析了医院计算机网络安全的相关因素,阐述了计算机网络安全主动防御模型,同时深入地分析了计算机网络安全主动防御技术的体系架构,以便人们更好地使用计算机,提升计算机使用的感知度。     

Measuring the relation between computer use and reading literacy in the presence of endogeneity

This work studies the relation between computer use for reading activities and academic literacy in 15-year-old students in Chile, Uruguay, Spain, and Portugal. Data used is from the PISA 2009 test. Special attention is given to potential bias problems when the computer use is an endogenous variable. Few studies in this area address this issue: existing literature has shown that different types of computer use have different implications on performance. The limitations of observational data have also been emphasized to establish cause–effect relations between computer use and academic performance. It is important, however, to consider the computer use endogeneity hypothesis (above all at home) since students decide on the frequency of computer use at home. The results found show that by controlling for endogeneity, computer use for reading is not related to reading performance neither in digital or printed format, with the exception of Chile that shows a negative relation in the case of reading from a printed format. The results considering endogeneity differ considerably from results when endogeneity is not taken into account. The work shows the relevance of experimental type studies in order to make sound statements with regard to the computer use and academic performance relation. In turn, school reading activities in a digital environment are suggested that could have an impact on reading performance.