基于LabVIEW的高精度铂电阻测温系统设计

针对铂电阻测温的特性结合虚拟仪器技术,设计了一种高精度温度测量系统;采用四线制恒流源温度测量电路克服由于铂电阻引线带来的误差,同时利用LabVIEW软件完成曲线拟合,最后对温度测量系统误差进行了分析;测试结果表明,系统具有测量精度高、可靠性高、使用灵活等特点,当被测温度范围在8℃～100℃之间,测量的绝对误差小于±0.1℃,可广泛使用于要求高精度温度测量的领域。     

基于铂电阻的温度高精度测量研究

针对采用铂电阻对温度进行高精度测量,从硬件电路和曲线拟合2个方面进行了研究。电路上采用同一个电压给传感器恒电流驱动电路和A／D转换电路作参考电压,保证了温度检测的精度,并用最小二乘法直接拟合了描述采样值一温度关系的曲线,弥补了Pt100测温时信号从铂电阻到A／D转换的过程中各个中间环节所产生的偏差。该方法可使测量偏差优于0．05℃,并已在研制的高精度温度温差控制系统中得到应用。     

基于PT100的高精度温度测量电路的设计

普通四线制恒流源驱动测温系统受温度电流漂移等影响,温度测量准确率很低,很难超过0.1℃量级.基于PT100设计了一种改进的恒流源驱动四线制高精度温度测量电路,通过采样温度稳定系数高的高精密电阻的电压和铂电阻电压的比值,消除了恒流源由于温度漂移等因素影响的电流变化,使得输出电压比值与铂电阻成良好的线性关系.利用LTC2492A/D转换器对信号进行采样,将信号传送给ATMEGA32单片机,单片机进行数据处理并保存和显示数据.实验测试结果表明,该电路温度测量的精度和稳定性均可以达到5‰之内,与理论值一致.     

虚拟仪器平台下的高精度铂电阻测温系统设计

通过对铂电阻测温与虚拟仪器的研究,提出了一套高精度多路温度自动测试系统的设计方案.着重从铂电阻非线性特征,温度信号调理电路和LabVIEW软件设计方面进行了阐述,并讨论了在复杂电磁环境下的EMc设计.该方案灵活可变,具有一定的扩展性和通用性,成功地应用于燃料电池汽车DC/DC变换器的温度测试系统中.     

基于放电时间测量的温度传感器设计

该文介绍了一种基于放电时间测量原理的温度传感器设计方法，不同于传统测温电路对铂电阻两端电压经过信号放大，再进行模数转换（AD）测量温度，该方法直接将温度变化引起电阻应变的测量转化为对电阻放电时间的测量，再根据放电时间进行解析得到当前被测温度。首先介绍了放电时间测量温度原理，其次详细介绍了基于高精度时间测量芯片TDC-GP22的温度测量电路，然后介绍了温度测量的软件实现方法，最后在温度校准装置中进行温度试验，验证了该设计方法的准确性。     

基于铂热电阻的高温检测系统设计与优化

为了实现基于金属铂材料制作的热电阻温度传感器在高温测量环境下实现对温度数据的高精度测量,提出一种基于优化电路参数及阻温方程参数的温度检测系统设计方案。设计利用恒压源电路,获得稳定的理想电压,通过不平衡电桥差分放大电路和二阶有源滤波电路得到理想采集信号;设计优化了电路参数,校正了铂热电阻因高温产生的非线性。通过熔融沉积成型(FDM) 3D打印喷头实验平台,验证了设计方案的有效性,实现了在高温测量环境下对温度数据高精度测量的目的。     

基于差动电容的高精度倾角测量系统设计

介绍了一种新型的高精度倾角测量系统。采用差动电容式倾角传感器与温度特性好的精密电阻器构成阻容电桥,用文氏振荡电桥作为激励源,用差动放大电路组成阻抗变换和前置放大电路,采用低功耗18位A／D转换器MAX132对模拟电路调理后的直流模拟电压信号进行转换。提出通过在A／D转换器参考电压的电路中接入热敏电阻器的方法实现温度补偿。经过试验验证,该倾角测量系统达到了高分辨率、高稳定性和低功耗的设计要求。     

精确预测卫星寿命终了时低重力推进剂的测量系统

术文描述由休斯航空公司研制、试验和取得专利的低重力推进剂测量系统(PGS)。PGS 在通常卫星预定15年飞行寿命中预测卫星寿命终了(EOL)的准确度在±2月之内甚至更佳。该系统已用于休斯 HS601同步通信卫星。PGS 从初始设计就简化并尽力减少系统所要求的硬件。现有的挤压气体箱和推进剂箱中间装有高分辨率传感器和内接阀门。PGS 通过瞬间打开对应的高压挤压气箱与推进剂箱之间的互连阀对推进剂周期性地加压进行测量。根据加压前后压力的测量值,应用气体定律计算可以确定推进剂箱中气体的体积,进一步可以得到液体的体积,这样就计算出箱中推进剂的质量。应用气体定律时也需要测定温度。为精确测定温度,每个贮箱都安装了多个温度敏感器,为进一步提高精度,使用非常精确的高分辨率的压力传感器作为气体温度计。通过对所推荐的测量方案的原型机试验,建立了对系统精确预测由于推进剂耗尽而引起的卫星寿命终了的能力的信心。PGS 具有容错能力,不受推进剂分系统正常工作的干扰。加压能力为双元推进系统额外提供了精密地控制氧化剂-燃料混合比的好处,这样通过使伴随某种推进剂比另一种先耗尽时使推进剂的残留量降到最低来提高位置保持寿命。     

基于卡尔曼滤波的铂电阻高精度水温测量系统设计

为满足地下水温度高精度测量的要求,设计了一种基于卡尔曼滤波的铂电阻高精度水温测量系统。硬件上,以铂电阻Pt1000为温度传感器,选用四线制比值法消除引线电阻干扰,并通过限流电阻和频率式供电避免铂电阻自热效应。软件上,通过卡尔曼滤波算法和线性拟合提高了阻值测量的准确度和稳定性,使用反向函数法对Pt1000分度表进行分段拟合,以减小铂电阻非线性误差。试验结果表明,该系统在-20～+100℃内,最大误差为0.05℃,整体精度优于0.044%。该研究对相关铂电阻测温设计具有一定借鉴意义。     

基于铂电阻传感器的高精度温度检测系统设计

介绍了一种基于铂电阻传感器的高精度温度检测系统,用于星载微波辐射计定标源的精密测温,测温精度为±0.1℃。针对铂电阻引线带来的测量误差这一缺点,设计了四线制恒流源温度测量电路,同时对铂电阻传感器温度检测电路的测量误差进行了分析。系统具有精度高、可靠性高,使用方便的特点,当温度范围在-200℃~650℃之间,误差小于±0.1℃时,也可用于其它工业测温以及航空航天精密温度检测领域。     

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.