管道应力危害BOTDR分布式光纤检测系统

针对长距离地下油气管道因地质沉降导致管道应力破坏的问题,本文提出了基于布里渊光时域反射（BOTDR）原理的分布式光纤应变检测方法。理论分析了油气管道受地质沉降产生应力变化的检测原理,设计了BOTDR分布式光纤应变检测系统。通过累加平均进行信号降噪处理,同时融合列文伯格-马夸尔特（Levenberg-Marquardt）算法,改善系统测量精度。系统性能进行测试,结果表明,系统检测距离可达10km,应变最大量程为8500με,应变测量误差为±46με、重复性测量偏差为±36με,定位误差为±2m,空间分辨率为1m,满足对管道沿线受应力危害的预警需求。     

面向航空发动机的高精高频动应变测量系统

高速高精动应变监测技术是实现航空发动机旋转部件故障早期诊断目标的关键技术。提出了一种基于相位解调技术的光纤法布里-珀罗(Fabry-Pérot, F-P)动应变测量系统,实现了在高频率条件下的高精度动应变测量。实验结果表明：系统中F-P传感器对应变的灵敏度可以达到100.955 pm/με,约为一般光纤FBG应变传感器(应变约1 pm/με)的100倍;测量频率可以达到10 kHz;在对多种不同标准激振频率进行测量时,误差不超过1.1%;另外测量系统探头能耐受1 200℃的高温,因而在未来航空发动机旋转部件故障监测、性能测试方面都具有较好的应用前景。     

双F-P型高温/应变复合光纤传感器

针对机电设备多状态监测的需求,提出了一种新双F-P腔光纤温度/应变复合传感模型。该光纤复合传感器采用纯石英光纤作为材料,通过化学腐蚀法及使用准直毛细管制作了双F-P腔,分别用以温度和应变测量,并对制作的传感器进行了传感性能的模拟仿真和实验验证。实验结果表明:该双F-P腔光纤复合传感器测量的最高温度为1 000℃,温度灵敏度为10.998 pm/℃,满量程温度测量误差小于2%;该双F-P腔光纤复合传感器测量的最大应变为10 000με,应变灵敏度为3.268μm/με,应变测量误差小于2%。所提出的双F-P腔温度/应变光纤复合传感器实现了温度和应变的同时测量,可用于机电装备同一位置的温度、应变测量。     

基于LC谐振的无线无源应变传感器研究

研究一种平面螺旋电感和叉指电容并联结构的LC谐振无线无源应变传感器,利用LC谐振回路的谐振频率对不同应变的响应来表征传感器的应变特性,采用电感耦合的方式来实现无线检测.结果显示LC应变传感器的谐振频率随外加张应变增加而降低,沿电容电极长度方向谐振频率变化对应变的响应灵敏度约为0.3 kHz/με,垂直于电容电极长度方向...     

Terfenol-D/SAW谐振器/Terfenol-D复合磁传感器

设计了一种由超磁致伸缩材料Terfenol-D和SAW谐振器构成的复合磁传感器,在磁场作用下,Terfenol-D沿长度方向伸缩,并将应力应变传递至SAW谐振器,使其产生应变,造成谐振频率改变,通过测量SAW谐振器谐振频率的变化来测量磁场强度.分析了该磁传感器的传感原理,建立了该复合磁传感器的静态模型,对弹性敏感元件进行了受力分析,根据压磁方程和受力平衡得到该磁传感器的静态特性.实验结果表明:该复合磁传感器灵敏度可达341.6Hz/Oe,较Terfenol-D/SAW谐振器结构灵敏度提高了3倍;测量谐振频率的分辨率为1Hz,SAW谐振器频率稳定度为0.1×10-6时,该磁传感器对磁场的分辨率为10-6T.     

单个光纤布喇格光栅实现应变温度同时测量的研究

实现单个光纤布喇格光栅同时测量应变和温度的实验系统.在该系统中,温度变化使光栅的布喇格波长位移,应变使反射谱分裂成双峰.结果表明,根据光栅的初始布喇格波长和两个分裂的布喇格波长可以同时确定应变和温度的变化.应变和温度灵敏度的实验结果分别为1.172 pm/με和10.78 pm/℃.该系统在结构健康监测、智能材料和结构等领域有应用前景.     

基于纳米晶软磁合金的电感式应变花的研究

利用纳米晶软磁合金良好的压磁特性,设计了一种用于测量平面应力的电感式应变计。首先,介绍了这种应变计的结构和工作原理,并推导出其输出数学模型。其次,进行了可行性试验。试验表明,应变计每一测量轴的输出电压主要取决于该测量方向的应变,其灵敏度可达3.86 mV/με,线性度为1.03%F.S,重复误差与迟滞误差均小于1%F.S。在平面应力状态时,不同方向应变相互耦合对测量精度的影响,通过标定补偿灵敏度系数对应变计的输出加以修正。与传统的电阻式应变计相比,这种电感式应变计具有结构简单,工作可靠,使用寿命长,适应性强,灵敏度和测量精度较高等特点。     

干涉解调技术在光纤光栅传感系统中的应用

本实验的目的是为了将光纤光栅的传感特性应用于结构健康监测系统中,系统采用了基于迈克尔逊干涉技术的解调方法,将包含被测应变信息的FBG波长信号转变成相位信号,通过以89C51单片机为核心的单片机系统检测相位的变化,从而得到被测应变的大小.系统可用于静态应变和动态应变的检测,具有高分辨力、大测量范围的特点,传感灵敏度为0.3950°/με.     

基片式FBG在飞机蒙皮测试中的对称补偿研究

基片式FBG传感器封装结构在应变测试中受到广泛关注,尤其是在航空航天领域,其粘贴方式对监测飞机蒙皮应变具有重要意义。为了提高基片式封装结构的FBG测量飞机蒙皮应变精度,对薄板试验件粘贴基片式FBG传感器进行力学性能研究,实验结果表明传统粘结基片式FBG传感器方式会引起被测薄板材在拉伸过程中产生非线性变形。据此,通过ANSYS有限元分析软件仿真粘贴1 mm传感单元的1.5 mm薄板静态加载过程,并进行静力学有限元优化分析,力学分析及理论推导结果显示,对称粘贴基片式FBG传感单元能够解决应变与波长非线性关系,且能够有效补偿温度对测量的影响。搭建FBG解调系统与MTS力学测试实验系统,实验结果表明,在对称补偿的布点方式下,应变测试线性度为0.998,传感单元应变灵敏度为0.946 pm/με,提高了应变测试精度,可以有效的应用到飞机蒙皮应变测试。     

一种超磁致伸缩材料和声表面波谐振器构成的复合磁传感器

设计了一种新的超磁致伸缩材料和声表面波谐振器构成的复合磁传感器.该传感器将超磁致伸缩材料在磁场中产生的应力应变传递到声表面波谐振器上,改变其谐振频率,通过对谐振频率的检测进行磁场测量.该传感器可以用于静态和动态磁场测量,并且可用作无源、无线磁传感器.主要分析了该结构用于静态磁场测量的原理,给出了实验结果.传感器谐振频率的变化对于静态磁场变化的灵敏度可达132 Hz/Oe,谐振频率测量分辨率在1 Hz时,磁场测量分辨率可达10-7T数量级.     

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。