基于光纤光栅和虚拟仪器的桥梁监测技术研究

光纤光栅传感网络采用波长进行编码,对物理量进行全光测量,是大型结构监测理想的传感技术.虚拟仪器在信号分析、数据存储、网络传输等方面为开发测试系统提供了优越的条件.光纤光栅传感网络与虚拟仪器结合的大型桥梁健康监测技术满足了工程实践的迫切需要.     

光纤光栅传感技术在桥梁施工监控中的应用

为了满足桥梁顶推法施工监控的复杂要求,分析了光纤光栅传感器的结构和原理;研究了应变和温度交叉敏感以及波长解调等光纤Bragg光栅(FBG)传感技术应用中的关键问题.根据对桥墩受力变形的分析,结合实例设计了传感器参数.将虚拟仪器与FBG传感器相结合,可以利用虚拟仪器技术在信号采集、分析、存储和传输等方面的优势,实现光纤光栅解调与施工监控于一体,保证了施工安全和桥梁质量.     

基于光纤光栅传感的桥梁监测采集系统

光纤布喇格光栅对应力应变或温度微小变化而产生相应的中心波长变化,对该波长进行编码,利用角度调谐法布里-珀罗滤波器实现波长的调谐,指出了对解调仪同一通道选择传感器应参考中心波长的差异;通过光纤光栅传感器构建了一个实际应用的分布式光纤光栅传感采集网络,并结合嵌入式数据库,详细设计了采集系统软件模块,该系统在国内多座大型桥梁健康监测中得到应用,为桥梁健康监测系统提供了长期在线和准确可靠的海量数据.     

基于光纤光栅和虚拟仪器的桥梁监测技术研究

光纤光栅传感网络采用波长进行编码,对物理量进行全光测量,是大型结构监测理想的传感技术。虚拟仪器在信号分析、数据存储、网络传输等方面为开发测试系统提供了优越的条件。光纤光栅传感网络与虚拟仪器结合的大型桥梁健康监测技术满足了工程实践的迫切需要。     

基于FPGA的光纤光栅传感解调系统设计

设计一款FPGA的光纤光栅传感解调设备,实现光纤光栅传感的低成本高速解调。该光纤光栅传感解调设备由数据采集和A/D模块、FIR数字滤波模块、数据缓存模块和显示模块4大核心模块组成。系统由FPGA主控模块为各个子模块提供全局系统同步时钟。与现有的基于FPGA的光纤光栅传感解调仪相比,设计所需元件均嵌在同一块FPGA开发板上,不仅降低了解调仪的成本而且提高了系统的集成度。实验验证,系统的数字信号处理模块设计合理正确。最后,提出了设计的一种应用,具有一定的实用意义。      

基于多级衍射及自适应补偿的光纤光栅传感器解调技术

解调技术是决定光纤光栅传感解调系统速率、精度、容量等性能的关键因素。提出一种基于线阵光电探测器成像原理的光纤光栅传感器解调方案,通过多级衍射,结合弱曝光自适应超频技术和FPGA并行数据处理技术,实现了对传感信号的快速解调,同时可以实现对级联型光纤光栅传感器和长周期光纤光栅传感器信号的解调。使用温度、应力敏感光纤光栅传感器对搭建的铁路桥模型进行监测,实验结果表明,光纤光栅传感系统的解调精度可以达到10 pm量级,系统可测量光谱范围达50 nm,提高了传感系统的解调速率和精度,同时实现了光纤光栅解调设备的微型化。     

光纤光栅传感技术研究现状及发展前景

在分析光纤光栅传感技术独特优势的基础上,介绍了近年来国外学者对各种光纤光栅解调方案的探索;对光纤光栅分布式传感系统的设计和优化;对倾角、扭矩、流速等传感器的研制;综述了国外光纤光栅传感器在航空航天、建筑物、桥梁等大型结构的健康监测方面以及在能源化工等领域的主要应用实例。最后,讨论了光纤光栅传感器在进一步实用化、商品化过程中面临的困难和需要解决的关键问题,并对其应用前景做了展望。     

基于以太网的光纤传感信息远程监控系统设计

由光纤布喇格光栅(FHG)构成的光纤传感网络,在许多领域具有广泛的应用前景,日益成为国内外研究的热点.针对光纤传感信息集中处理、实时监测、远程控制等要求,提出一种基于以太网的光纤传感信息远程监控系统的设计.系统硬件设计部分采用基于DSP的F-P腔解调技术,软件设计主要采用VC++平台下的网络编程和数据库编程技术.     

光纤光栅传感器在称重系统中的应用

为了实现物体重量的测量,分析了光纤光栅传感器的结构和原理;研究了应变和温度交叉敏感以及波长解调等FBG传感技术应用的关键问题.根据对承重台受力的分析,设计了承重台的结构和传感器的安装方式,而且,摸索到了光栅传感技术的一些使用经验和注意事项,这些可为高速公路汽车称重系统所借鉴.利用FBG210解调仪在信号采集,分析,存储和传输等方面的优势,实现了光纤光栅解调.使用处理器对解调出的重量信号进行处理,并将其显示在LCD上.     

光纤Bragg光栅在动态应变测量中的研究

为了将光纤光栅的传感特性应用于结构健康监测和高频应力作用下的材料力学性能测试中,对光纤光栅动态应变传感的测量进行了研究.设计了基于相位载波(PGC)零差法的非平衡Mach-Zender干涉解调系统,并对相位载波解调技术进行了分析.通过对比冲击实验和频谱分析,实验结果证明该检测方法有效可行,可以得到稳定的测量信号,系统在10 kHz的频率范围内有良好的频率响应.     

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     

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。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。