Human Performance Comparisons Between Digital Pursuit and Compensatory Control

This experimental study compared human performance for pursuit and compensatory digital displays utilised in a digital control task with a first-order controlled system and a reference input that was either a purely random Gaussian noise or a first-order autoregressive process. The results for eight subjects showed that there were no significant differences between either the mean or the rms error performances for the two types of displays. The control errors, which were generally normally distributed with predominantly negative means, were clearly more pronounced when (a) the reference input was purely random than when it was a first-order autoregressive process (with a parameter α=0[sdot]95), and (b) the variance of the reference input was high than when it was low.     

硬磁盘与近场记录光盘浮动性能比较分析

本文分析了硬磁盘以及近场记录光盘记录密度与浮动间距之间的关系 ,在分析对比的基础上 ,得出了在同等浮动间距的情况下 ,近场记录光盘面记录密度比硬磁盘高大约 2 8倍 ;在同等面记录密度的情况下 ,对硬磁盘浮动性能的要求比近场记录光盘高近 10倍的结论 .     

图书馆可视化多媒体触摸屏导读与查询系统开发

该文介绍了原型法开发技术、ActiveX控件技术、基于Web的可视化技术以及这些技术在网络环境下运用于触摸屏导读与查询系统开发中的方法。     

视觉输入设备的对角线视角与Twiddler点击绩效的关系

Twiddle是可穿戴计算机最常用的输入设备,其点击绩效直接影响其可操作性和可用性.根据费兹原理,参考Paul Fitts所采用的反复敲击试验,建立了点击绩效测试系统.在相同的测试条件下,分别对以19寸液晶显示器和两款头戢显示器为视觉输入装置的情况下对Twiddler点击绩效进行了测试,在大量试验数据的分析基础上,结合赤池信息准则,得到了最优的Twidd-ler点击绩效模型.通过将3种情况下的Twiddler点击绩效模型对比分析,反映出Twiddler的操控比较困难,同时受视觉输入设备的影响较大,影响程度随着其所能提供的对角线视角的减小而增大.     

图书馆可视化触摸屏导读与查询系统的设计与开发

论文结合图书馆在信息化过程中所遇到的具体问题和需求,总结了我校在研制开发图书馆触摸屏导读与查询系统及成功应用的经验,介绍了该系统的整体架构设计和主要功能模块设计,为要制作触摸屏多媒体导读系统工作的图书馆提供参考。目前本系统的分析、设计、实现和测试己基本完毕,运行效果良好。     

GSM与GPRS在远程数据采集中的比较

介绍了远程数据通信中在空间电场测量项目的构成,讨论了GSM和GPRS的基本原理和应用,针对空间电场数据远程通信的情况,在部署方法、通信协议、费用以及时间延迟等方面对GPRS和GSM两种方案进行了比较.比较的结果表明.GSM Modem方式适合于通信频率小,数据延迟不敏感,费用低的场合;GPRS DTU方式适合于通信频率大,数据延迟小,数据量大,安全性要求高的场合.     

基于脉冲频率与输入电流关系的SNN训练算法

脉冲神经网络(spiking neural network,SNN)以异步事件驱动,支持大规模并行计算,在改善同步模拟神经网络的计算效率方面具有巨大潜力.然而,目前SNN仍然面临无法直接训练的难题,为此,受到神经科学领域关于LIF(leaky integrate-and-fire)神经元响应机制研究启发,提出了一种新的...     

Nomadic Input on Mobile Devices: The Influence of Touch Input Technique and Walking Speed on Performance and Offset Modeling

In everyday life, people use their mobile phones on-the-go with different walking speeds and with different touch input techniques. Unfortunately, much of the published research in mobile interaction does not quantify the influence of these variables. In this article, we analyze the influence of walking speed, gait pattern, and input techniques on commonly used performance parameters like error rate, accuracy, and tapping speed, and we compare the results to the static condition. We examine the influence of these factors on the machine learned offset model used to correct user input, and we make design recommendations. The results show that all performance parameters degraded when the subject started to move, for all input techniques. Index finger pointing techniques demonstrated overall better performance compared to thumb-pointing techniques. The influence of gait phase on tap event likelihood and accuracy was demonstrated for all input techniques and all walking speeds. Finally, it was shown that the offset model built on static data did not perform as well as models inferred from dynamic data, which indicates the speed-specific nature of the models. Also, models identified using specific input techniques did not perform well when tested in other conditions, demonstrating the limited validity of offset models to a particular input technique. The model was therefore calibrated using data recorded with the appropriate input technique, at 75% of preferred walking speed, which is the speed to which users spontaneously slow down when they use a mobile device and which presents a trade-off between accuracy and usability. This led to an increase in accuracy compared to models built on static data. The error rate was reduced between 0.05% and 5.3% for landscape-based methods and between 5.3% and 11.9% for portrait-based methods.     

基于决策树的ID3算法和C4．5算法的比较

阐明决策树分类器在用于分类的数据挖掘技术中依然重要,论述基于决策树归纳分类的ID3、C4．5算法,并且对决策属性的选取法则进行说明。通过实例解析ID3、C4．5算法实现过程,结果表明C4．5算法相比较于ID3算法的优越性．尤其在处理具有多属性值的数据时的更加合理和正确。     

具有输入约束和扰动补偿的四旋翼无人机姿态稳定模型预测控制

为了解决四旋翼无人机飞行过程中的姿态控制问题,考虑受到执行器输入约束和外界未知扰动影响,设计了一种具有输入约束和扰动补偿的四旋翼无人机姿态稳定模型预测控制方法;设计简化的四旋翼无人机姿态动力学模型,降低控制器设计的复杂程度,设计带有输入约束的控制器,模拟饱和输入现象,实现饱和输入下的四旋翼姿态稳定控制;设计风扰观测器,实现对外部未知扰动的估计,有效跟踪外部持续扰动,并由此设计扰动补偿律;围绕代价函数设计带有扰动补偿律的最优控制律,作用于四旋翼姿态系统,实现四旋翼无人机姿态的稳定控制;最后进行数值仿真,设置风扰观测器参数λi为0.25,预测时域Np为10,控制时域Nc为9,仿真测试本文方法与不带观测器的非线性预测控制方法（NMPC）,验证本文控制方法的有效性和优越性。     

基于STM32和触摸屏的缆料生产监测系统设计

为提高电缆缆料工业现场的生产管理水平、实时准确地监测现场的生产数据对电缆生产十分重要.缆料生产监测系统以STM32为主控制器,采集电缆缆料生产过程中的温度、压力和转速,通过RS485总线,结合Modbus通信协议,上传数据给MCGS触摸屏,从而实现生产数据的实时采集和显示.实际运行结果表明,系统工作稳定可靠,操作方便,人机交互性好,对类似的工业现场提高自动化水平有一定的借鉴意义.     

基于过程输入输出变化关系的模糊建模方法

针对难以建立精确数学模型的复杂过程,提出一种基于过程输入输出数据变化关系的模糊建模方法。首先按过程输出随输入变量变化的程度对输入变量论域进行划分,在此基础上确定模糊模型的规则总数和前件参数;然后根据所建模糊模型可表示为一个前馈模糊神经网络,利用BP学习算法求得过程模糊模型的后件参数。仿真例子验证了模糊建模方法的有效性,同时表明所建模糊规则模型较好的泛化能力。     

Evolutionary Algorithms for Multi-Objective Optimization: Performance Assessments and Comparisons

Evolutionary techniques for multi-objective(MO) optimization are currently gainingsignificant attention from researchers invarious fields due to their effectiveness androbustness in searching for a set of trade-offsolutions. Unlike conventional methods thataggregate multiple attributes to form acomposite scalar objective function,evolutionary algorithms with modifiedreproduction schemes for MO optimization arecapable of treating each objective componentseparately and lead the search in discoveringthe global Pareto-optimal front. The rapidadvances of multi-objective evolutionaryalgorithms, however, poses the difficulty ofkeeping track of the developments in this fieldas well as selecting an existing approach thatbest suits the optimization problem in-hand.This paper thus provides a survey on variousevolutionary methods for MO optimization. Manywell-known multi-objective evolutionaryalgorithms have been experimented with andcompared extensively on four benchmark problemswith different MO optimization difficulties.Besides considering the usual performancemeasures in MO optimization, e.g., the spreadacross the Pareto-optimal front and the abilityto attain the global trade-offs, the paper alsopresents a few metrics to examinethe strength and weakness of each evolutionaryapproach both quantitatively and qualitatively.Simulation results for the comparisons areanalyzed, summarized and commented.     

Nitrogen Narcosis and Performance Under Water

Abstract

Eighteen divers were tested four times under water, twice at a depth of 5 ft and twice at 100 ft. They performed three tests—digit copying, a sentence comprehension test and a manual dexterity test. All three showed a significant drop in efficiency at depth. This was small for digit copying (7-9 per cent) and manual dexterity (3 5 per cent), and somewhat larger for sentence comprehension (15-3 per cent). In all three cases the drop in efficiency was approximately the same as found at the equivalent pressure in a dry pressure chamber. This contrasts with previous results where impairment in the open sea has been considerably greater than in a dry chamber. Possible reasons for this discrepancy are discussed and it is suggested that level of anxiety may be a crucial factor.     

Solid Works软件与小型PDM系统集成技术研究

针对当前中小企业CAD系统与PDM系统集成中存在的问题,研究CAD系统与PDM系统的集成模式,设计三维CAD软件SolidWorks 2010与自行开发的小型PDM系统集成的功能模块,提出以封装模式与接口模式相结合实现由PDM端向SolidWorks端的集成,以接口模式和紧密集成模式相结合实现由SolidWorks端向PDM端的集成。通过调用SolidWorks API函数,完成产品结构树的遍历,并在SolidWorks软件中开发了插件＂CAD/PDM集成＂,集成该PDM系统的所有功能;在该PDM系统中更新产品结构树,实现SolidWorks与PDM系统的双向集成,保证了数据的完整性和一致性。最后通过系统的正常运行验证了集成功能模块设计和实现方法的正确性。     

几种名牌PLC产品的性能比较与发展趋势

本文在简单介绍现代可编程控制器性能、特点的基础上，着重分析了美国GE公司、德国西门子公司和日本OMRON公司产品在硬件结构上的特点，并说明了各公司产品的软件运行环境及发展趋势。     

辽优1052及其亲本灌浆特性与源库关系的比较

对直立大穗型杂交稻辽优1052及其母本105A、父本C52做减源、减库处理，研究了品种的籽粒灌浆特性。结果表明：3个品种均属于源限制型品种，都存在明显的两段灌浆现象，同一品种强、弱势粒间灌浆过程差异较大；源、库处理对籽粒灌浆的影响主要体现在弱势粒上，对强势粒的灌浆影响较小；与双亲相比，辽优1052在籽粒灌浆方面具有明显的杂种优势。     

基于PLC和触摸屏的3T压力机电控系统设计

阐述了非标设备3T压力机的电气控制系统设计,设备采用三菱PLC及GOT1000系列触摸屏组建监控电控系统.提出了系统设计要求,着重分析了系统软、硬件设计,并给出PLC接线图和部分梯形图.     

真实感布仿真中布与刚体的碰撞检测及修正

提出了一种快速碰撞检测与修正算法.在碰撞检测阶段,通过采用包围盒与层次结构模型结合的方法减少碰撞检测的次数,并把多种碰撞形式归纳为一种点-面碰撞,从而把解线性方程组简化为代数运算.在碰撞修正阶段,通过采用预条件共轭梯度法进行数值积分,将碰撞修正直接融合在数值积分过程中,提高了计算速度.     

基于性能指标约束的一类输入死区非线性系统最优控制

针对一类考虑指定性能和带有输入死区约束的严格反馈非线性系统,本文提出了一种自适应模糊最优控制方法.采用模糊逻辑系统逼近系统的未知非线性函数及代价函数,利用backstepping方法及命令滤波技术,设计前馈控制器.针对仿射形式的误差系统,结合自适应动态规划技术,设计最优反馈控制器.采用指定性能控制方法,将系统跟踪误差约束在指定范围内.利用死区斜率信息解决具有死区输入的非线性系统的控制问题.基于Lyapunov稳定性理论,证明闭环系统内所有信号是一致最终有界的.最后仿真结果验证了本文方法的可行性和有效性.