基于双金属膜和法布里-珀罗干涉结构的光纤温度传感器

研究了一种新型的光纤法布里-珀罗干涉腔(F-P腔)结构的温度传感器,该传感器的F-P腔由双层金属膜和光纤端面构成,当被测温度发生变化时,基于双层金属膜的"双膜热挠曲效应"使得F-P干涉腔长发生变化,从而导致F-P腔输出的光强发生变化,通过测量该光强的变化即可测定相应的待测温度.在理论分析的基础上,运用有限元分析软件ANSYS对传感器的结构参数进行了优化,并对加工和封装后的传感器进行了实验测试,实验结果表明该传感器在测温0 ～ 80 ℃的范围内灵敏度达到了 62.82 nw/℃,综合精度优于±0.7%.该传感器具有结构简单、成本低、量程可根据双金属膜参数自由选择以及灵敏度较高等特点.     

E型碳化硅压力传感器的优化设计

描述了一种性能优越的SiC压力传感器的理论和仿真运用基于小扰度的解析模型计算出了这种传感器的应变分布.根据应变分布规律优化设计了传感器的力敏电阻.利用ANSYS软件分析了该传感器的一些重要特性.与传统的传感器(圆膜传感器)相比,量程为500 kPa的该传感器表现出优异的灵敏度(24.8 μV/V.kPa)和非线性度小于0.08%.仿真结果与测量结果基本一致.     

FBG应变传感器标定过程中的不确定度研究

为实现光纤Bragg光栅(FBG)应变传感器静态的性能测试和试验分析,设计了一种量程为700×10-6的FBG应变传感器标定装置对其进行校准实验.通过运用最小二乘法对解调仪中的中心波长和计算得出的应变量进行拟合,得到FBG应变传感器的静态标定系数,并分析标定装置的不确定度大小.结果表明:该FBG应变传感器标定装置合成不确定度是2.55×10-6,标定得出的FBG应变传感器的灵敏度1.37 ×10-3nm/10-6,线性度为99.72％,满足FBG应变传感器的标定要求,该传感器能够运用于工程实际中.     

高灵敏集成光学加速度计的优化设计

针对基于光弹效应的集成光学微腔悬臂梁式加速度计难以同时实现高灵敏度和高抗冲击性的问题,提出增加光学微腔周长的方案。经过详细的理论分析得出:通过增加微腔周长可以有效地增加惯性力下微腔谐振点波长偏移量,提高探测灵敏度。设计了多回路长直跑道型微腔结构,在100μm×600μm悬臂梁区域内集成出周长达5297μm的硅微谐振腔。利用MEMS工艺制作出所设计的微腔结构,测试品质因数达105。该结构应用于加速度等传感器中,在不减小传感器抗冲击性和量程的前提下,能有效提高探测灵敏度。     

矩形岛结构SiC压力传感器的性能研究

运用非线性理论及有限元方法(ANSYS)研究了矩形岛结构的应力和非线性.应力与矩形岛长度之间的关系表明:使用矩形岛结构能使输出应力增大,可以提高灵敏度.应力的非线性随矩形岛长度增加而减小,矩形岛长度取接近应力最大值处的值.根据应变分布规律优化设计了传感器力敏电阻应变计.与常用的传感器(方膜传感器)比,设计为10kPa量程的SiC压力传感器显示出灵敏度高、非线性小和工作温度高等特点.     

宏弯型光纤位移传感器的分析与设计

提出了一种宏弯型光纤位移传感器的优化设计方法,通过分析聚合物光纤的宏弯光损耗特性,结合光纤宏弯物理结构的建模仿真。设计出了线性度好、量程大、结构简单的宏弯型光纤位移传感器。并得到了实验验证、仿真和实验结果表明,该光纤传感器的理论线性度最高可达 0.99997。实验测试线性度可达0.99922,测量量程可达 27mm,可以满足实际应用需。     

大量程六维力传感器设计与标定研究

为提高大量程六维力传感器的灵敏度,设计了一种适用于机械臂末端的应变式传感器.该传感器采用十字梁式弹性体结构,通过优化应变梁结构和合理布置应变片等方式,使传感器在大量程条件下仍具有较高的刚度和灵敏度.使用有限元法分析验证了传感器应力分布的合理性,并根据最小二乘法标定原理对传感器进行解耦标定实验,实验结果表明:传感器静态性能良好,最小灵敏度为0.375 mV/N,满足使用要求.     

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。     

增敏微型FBG应变传感器设计

提出了一种两端夹持套管封装的光纤Bragg光栅(FBG)应变传感器,其结构包括光纤光栅、夹持套管、尾纤3部分,夹持套管封装的传感器尺寸小,可以改变灵敏度系数,测量精度高,适用于应变较小、受尺寸限制的室内模型试验.测试结果表明:增敏微型FBG应变传感器灵敏度高、低噪、稳定可靠,在标距范围内线性关系良好,线性度均达到0.999以上,制作工艺简单,具有很高的实用价值.     

考虑混凝土弹塑性的植入式GFRP封装FBG传感器应变传递分析

工程化FBG传感器的封装层引入的应变传递损耗使其具有应变传递误差,需进行应变传递分析。已有研究多聚焦于基体处于线弹性时的应变传递分析,而混凝土结构发生弹塑性变形后的应变传递规律尚未明晰。以植入式GFRP封装FBG传感器为对象,在应变传递分析中引入混凝土的非线弹性本构关系,建立了基体与FBG的应变传递关系,通过有限元模拟验证了该理论推导的有效性。基于理论分析探讨了混凝土弹塑性演化、混凝土标号、传感器半径与标距等因素对应变传递效率的影响,并分析了传感器的尺寸设计。研究表明：平均应变传递率在混凝土弹性阶段变化较小,而到塑性阶段则显著降低,混凝土标号、半径与标距都会对应变传递效率产生较大影响。本研究可广泛用于植入式FBG传感器的应变传递误差修正及设计。     

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。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.