大尺寸工件视觉测量中的图像拼接方法

为提高大尺寸工件机器视觉测量精度,提出一种基于坐标变换的图像拼接方法,并给出该坐标变换方法的解算模型及求解方法,分析了局部测量误差、重叠区域公共点个数等对坐标变换精度的影响,得到了最佳拼接条件,并通过实验对其进行了验证;实验结果表明,该方法简单易行、结果可靠,对存在平移、旋转以及尺度缩放的图像都具有良好的效果,能有效地解决采用机器视觉进行大尺寸工件精确测量时的坐标归一化问题。     

糖厂澄清工段生产指标建模及操作参数优化

针对亚法糖厂澄清工段清汁色值和清汁残硫量难以在线测量的问题,提出了一种基于人工蜂群优化的在线极限学习机软测量方法;先用核主元分析法确定影响清汁质量的关键参数,建立基于在线极限学习机的软测量模型;同时利用人工蜂群算法对在线极限学习机的隐层参数进行寻优,优化所建模型;最后,使用带约束的粒子群对软测量模型进行优化求解,得到典型工况下的最优操作设定值,为后续工况操作提供参考依据;仿真结果表明,基于人工蜂群优化的在线极限学习机模型能够准确地预测清汁色值和残硫量,同时基于此模型优化的操作参数设定值能够达到期望的指标.     

基于多功能数据采集卡和变速PID的转台控制系统设计

为了提高采用转台对惯性导航系统和惯性仪表进行误差模型标定时的可靠性和精度,对角位置转台的控制系统进行了研究;首先借助NI公司PXI-8101控制器和功能强大的数据采集卡PXIe-6363对转台控制系统进行了硬件设计;随后在对转台常规PID控制方法研究的基础上提出了一种能随系统调节偏差自动改变积分项累加速度的变速PID控制方法;接着又对基于软件实现的双通道旋转变压器轴角解调算法进行了研究并提出了一种粗精组合角纠错方法;最后文章设计的转台控制系统进行了测试实验,结果表明提出的轴角解调算法具有较好的解码速度和精度,并且变速PID控制方法大大提高了转台控制系统的自学习能力和鲁棒性,显著地改善了转台控制过程的稳定性.     

外观设计在挤出吹塑中空成型机中的应用研究

工业产品外观设计不是单纯的美术设计,它是科学、技术、艺术和经济的结合体,是从实用和艺术的综合角度出发,实现产品功能与形式的完美结合,进而达到优化产品结构、提升产品性能、重塑产品品牌形象的目的。通过对中空成型机的自身结构、工艺流程等特征分析,从工业设计的角度对产品框架结构及外防护进行设计,达到产品的机械美、结构美及艺术美的综合体现的目的,实现产品由内而外的改变,凸显产品的功能性与艺术性。     

无线传感网络的3D粒子群定位算法

设计了一套基于粒子群算法的ZigBee无线传感网络3D定位算法。采用ZigBee节点JN5148进行测距,并对测距效果和误差进行分析。在设计粒子群算法目标函数时,根据测距距离远近赋予数据不同权重。仿真实验证明,本文定位算法性能良好。     

IXP425和DM642的会议电视多点控制单元硬件设计

介绍了采用IXP425作为核心主控单元和3片DM642作为核心数据处理单元的会议电视多点控制单元的硬件设计原理和实现方法。主控制器IXP425模块完成网络发送/接收、数据调度、PCI控制等功能。数据处理DM642模块完成音/视频混合与切换等功能。IXP425和DM642之间采用PCI总线连接,各模块之间数据传输速度快,提高了数据处理效率。     

无线网络安全技术分析

文章首先分析了网线网络面临的安全隐患,基于此围绕网络安全的核心要素:认证、加密、完整性,介绍分析了物理地址(MAC)过滤、服务区标识符(SSID)匹配、有线对等保密(WEP)、端口访问控制技术(IEEE802.1x)、WPA?(Wi-FiProtected Access)、IEEE802.11i等无线网络安全技术的原理,并结合典型应用场合给出了相应的无线网络安全策略方案。     

图像增强在基于形状特征图像检索中的应用

基于内容的图像检索系统中需要提取图像的形状特征,通常情况下为得到形状特征,需要对图像分割来得到的目标边界。在对不均匀图像提取边界曲线时,噪声点和非噪声区域常会干扰导致小的边界变化。本文采取了一定的措施对该问题进行了改进:首先通过去掉图像的彩色成分,将图像进行灰度化处理,再通过图像增强技术,对图像进行平滑处理,然后提取图像的形状。由于图像增强对图像预制模糊时,已经对图像中的噪声点和颜色不均匀区域进行了处理,所以再次对图像进行形状处理时,可有效去除噪声点和非噪声干扰区域的影响。     

File-aware P2P traffic classification: An aid to network management

As P2P dominates Internet traffic in recent years, ISPs are striving to balance between providing the basic networking services for P2P users and properly managing network bandwidth usage. That is, ISPs are required to provide proper bandwidth for each P2P user to get every file to fulfill their provision for communications, while they have to control bandwidth consumption for efficient usage. However, current P2P traffic management strategies are unable to satisfy both requirements. In this paper, our goal is to design a simple and effective scheme for ISPs to moderate the tradeoff. It is achieved by proposing a file-aware P2P traffic classification method that can identify files and the associated flows. The file-level information can lead to more efficient and flexible management strategies on a per-file basis. We offer two alternatives: constraining the per-file bandwidth consumption and the number of per-file concurrent flows. Finally, a real-life trace is measured using our file-aware method from the perspectives of peers and files. The results indicate that ISPs can gain enough opportunities to flexibly choose proper traffic manage parameters according to actual demands.     

Understanding User Satisfaction With Instant Messaging: An Empirical Survey Study

The current article examines user satisfaction with instant messaging in building and maintaining social relationships with friends, family members, and others. The research model integrates motivation theory with media capacity theories to explain how the attributes of media capacity (e.g., social presence and media richness) and users' intrinsic and extrinsic motivations toward using instant messaging influence user satisfaction. Data were collected from a sample of 247 Chinese university students via an online survey. The results suggest that perceived enjoyment, perceived social presence, and perceived usefulness are key to user satisfaction. Perceived social presence and perceived media richness are positively associated with perceived enjoyment. It was also found that perceived enjoyment, perceived social presence, and perceived media richness have significant effects on perceived usefulness. Of interest, perceived enjoyment and perceived social presence have stronger effects on user satisfaction than perceived usefulness.