半封闭连通管式差压传感器在桥梁挠度测量中的应用

挠度是评价桥梁结构安全性的重要指标。根据桥梁结构特点,选用半封闭连通管式差压传感器进行实际工程应用。论述了传感器的基本原理,介绍了实际的半封闭连通管式差压传感器及其系统的构成,并将该传感系统应用于荆岳长江公路大桥通车鉴定试验的静载挠度测量中,测量结果表明:半封闭连通管式差压传感器的测量数据能够有效地反映桥梁结构状态变化,且具有较高的测量效率和准确度。     

基于差分光斑中心定位算法的位移传感技术研究

光斑中心定位是激光投射式位移传感技术中的关键技术.为了提高激光光斑中心检测的抗干扰性和精确性,在总结了现有的光斑中心定位方法的基础上,对其中的梯度光斑中心定位算法进行分析和改进,提出了一种差分光斑中心定位算法.该算法主要针对强干扰光线下的激光光斑特点,利用差分运算和梯度算子对光斑进行识别与定位.实验结果表明,该算法定位...     

栅式电涡流传感器在桥梁挠度测量中的应用

根据桥梁变形的特点提出了一种三点测量法的梁体挠度测量新方法,在沿着桥梁轴线方向上等间隔选取测量点,令每3个相邻的测点为一个测量单元,通过安装在这些测量单元中的栅式电涡流位移传感器可测量得到该单元中间测点相对于两个端点连线的相对挠度,而后可根据这些相对挠度计算出每个测点绝对挠度值;为了验证该方法的有效性,通过在简支梁模型上进行的一系列静态、动态挠度测量实验证明了该方法准确、稳定可靠。     

一种激光图像挠度测量方法

分析了当前桥梁挠度测量方法中的激光测量法和成像式测量法的原理,讨论了两种方法的优劣,在综合二者优点的基础上提出了一种激光图像挠度测量的新方法。并在实验室构建出整个测量系统,进行了室外和室内的测试。实验结果表明:在测量环境基本维持不变的条件下(如密封的梁体),系统漂移较小,完全可以满足具有密封梁体的大型刚构桥梁的高精度、大量程的挠度测量要求。     

激光传感器扫描边缘系统定位方法研究

非接触式齿轮倒角测量系统物体坐标系与运动平台坐标系的系统定位是通过人工控制XY移动平台携带激光传感器运动使激光点投射到棋盘格左下角点,该方法存在一定的人为误差,增加了齿轮倒角测量的系统误差[1].提出用激光位移传感器扫描测量标定板右侧和下侧边缘突变点位置坐标来确定标定板右下角点位置坐标信息,棋盘格有效区域左下角点与标定板右下角点间的距离已知,控制XY二维运动平台运动,使激光点投射到棋盘格有效区域左下角点的位置,完成系统定位.     

二维激光图像挠度/位移测量系统的结构性误差及解决方案研究

为提高二维激光图像挠度/位移测量系统的测量精度,通过对系统的结构特点及其可能造成误差的原因分析,从结构和设计上对系统进行了包括对称激光器安装、弱衍射激光准直装置和激光靶标的水平安装等方面的改进.通过改进,系统有效地消除了因结构原因造成的不稳定性,显著提高了系统精度.实验证明,改进后的系统精度大大提高并可投入工程中直接使用.     

基于激光三角法的同步扫描形貌测量传感器

为了克服传统的激光三角非同步物体形貌测量传感器,在深度方向的测量精度和横向测量视场相互制约的固有缺点,设计了一种新型的激光同步扫描物体形貌测量传感器.传感器以激光三角测量法为基本原理,通过所设计的光路系统,实现激光投射方向与相机成像方向的同步扫描.本文研制了基于高速旋转的十二面转镜和线阵CCD相机为主体的实验样机,实现了测量深度方向和横向视场的相互独立,并结合精密电控位移导轨和激光跟踪仪等搭建了实验系统平台.在传统非参数标定方法基础上,提出了一种适用于该传感器的映射标定方法,能够准确快速的标定该传感器.系统利用激光跟踪仪进行比对实验验证,结果表明:单点重复性小于0.07 mm,测量精度优于0.25 mm.测量传感器具有精度高、速率快、稳定性好等优点,对于物体表面形貌快速精密测量有着广泛的应用前景.     

微型计算机与传感器技术讲座(四)

第五讲位移传感器根据位移的特征,可分为线位移和角位移。线位移是指机构沿着某一直线移动的距离,所以,线位移的测量又称长度测量。一、线位移传感器根据传感器的变换原理,常用的线位移传感器有电位计式位移传感器、电感式位移传感器、差动变压器式位移传感器、电容式位移传感器、感应同步器以及磁栅、光栅、激光位移传感器等。根据输出信号,位移传感器可以分为模拟式和数字式两种。     

“新型传感技术”知识讲座 第二讲 传感技术的特点及共性技术

一、传感技术的发展特点在传感器领域内,目前实际使用得最多的仍然是结构型传感器,例如在工业流程中广泛的采用力平衡型、电容型、电感型、振弦型等传感器来测量压力、位移、流量、温度等。但是随着新型材料的开发,相关技术的应用以及制造工艺的改进,传感器技术的发展具有以下特点:     

基于光学微腔的MOEMS微位移传感器

该MOEMS微位移传感器是一种基于光波导环形谐振腔的悬臂梁式传感器,通过一系列的微加工技术集成制造在SOI材料上.光学微腔是一种新型的光学谐振腔,当其在回音廊模式下(WGM)共振时可以检测到规则的透射谱图,该传感器通过测量透射谱的偏移来确定位移量.利用有限元分析法可以得到悬臂粱结构的最佳尺寸参数,利用时域有限差分方法(FDTD)可以得到环形腔投射谱的偏移特性.当使用跑道型谐振腔时,该新型传感器最高可以探测到10nm左右的位移量.     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。