基于Sigma-Delta调制的电容传感器设计

提出一种基于Sigma-Delta调制的电容传感器芯片,采用三阶Sigma-Delta调制技术实现了电容到数字信号的直接转换,并通过补偿电容器矩阵扩展可测电容值范围,利用电流饥饿型OTA提高运放电流利用率,降低整体功耗。采用SMIC 0. 18μm CMOS工艺,利用Cadence工具对电路进行仿真验证,在2 V的供电电压下,共消耗电流18. 6μA,0. 8 ms转换时间内,调制器实现三阶噪声整形功能,可测输入电容范围为0～8 pF,并实现良好的线性度。     

直流稳压电源及漏电保护设计

本系统采用两级稳压的方式,前级稳压芯片将高输入电压降至8.2 V左右,后级稳压采用低压差稳压芯片MIC29302。系统根据输入电压自动选择相应的稳压回路,从而保证电压控制精度、电压调整率和负载调整率。采用霍尔传感器检测漏电电流,当漏电电流超过30 m A时,能准确切断电源并发出报警。数字电路以单片机为核心,实现电压与电流的显示、故障报警、键盘数字给定。本系统功能完善,达到了各项设计指标。     

基于单片机的防火漏电保护器设计

防火漏电保护器是通过检测三相交流电的电压、电流和漏电对用电电路实施保护的装置。当三相交流电的电压、电流和漏电出现故障时,切断电源电路。本文从防火漏电保护器设计出发,以单片机为核心,从硬件和软件两方面详细论述了防火漏电保护器的设计过程。     

双极型步进电机的斩波驱动电路设计

设计了一款用于双极型步进电机的斩波驱动电路,采用可变增益放大器实现电流检测和角度细分以提高精度,采用新型低功耗功率放大电路降低芯片功耗,并采用0.35μm BCD工艺,最高输出电压为35 V,驱动能力为±2.5 A。测试结果表明,负载电源静态电流为3.9 m A,功率管导通电阻不超过0.23Ω,斩波电流误差小于8%。     

一种带隔离的电压电流检测电路

基于LTC4151芯片及光隔离器件设计了一种带隔离的电压电流检测电路,电压检测范围为DC 7～80 V,最大分辨率25 mV;配置采样电阻10 mΩ,电流检测范围0～8 A,最大分辨率2 m A。该隔离电压电流检测电路检测精度较高,可推广到其他电路系统中应用,具有一定的实用意义。     

一种宽带全量程示波器信道保护器研制

基于THS3491运算放大器芯片研制示波器信道保护器,应用在脉冲辐射场诊断测试之中。研究测试了SOIC、 VQFN两种封装的THS3491的幅频特性曲线,采用VQFN封装的THS3491作为保护器的核心芯片;研制的保护器输出电压幅值范围为±10 V(50Ω负载),等效电噪声峰峰值约为2 m V;-3 dB小信号带宽约为850 MHz,0.3 dB平坦度带宽约为710 MHz,发现并理论解释了保护器输出电压的峰移现象。通过delta脉冲信号源对保护器进行测试,对比输入输出电压波形,实现了无失真的delta响应;在输出信号电压幅值范围超过±10 V时,保护器进入到输出保护状态,输出恢复时间小于7 ns,可以很好满足脉冲辐射场诊断中的示波器信道保护要求。     

超快速单相电漏电、短路保护电路仿真分析

提出了一种超快速识别家用电器漏电、短路保护电路,包括电源基准电路、综合时间延长电路、开关控制电路和漏电、短路识别电路。采用快速恢复场效应管作为开关元器件,提升电路分断时间。制作特殊的差分电流互感器,作为快速识别漏电部件。对开关控制电路的驱动信号进行时间延迟,在延迟时间内试探故障是否解除。采用软件对电路进行仿真验证,仿真结果表明,在电路发生漏电、短路时,能够快速地识别故障和分断主回路,时间控制在15 ms以下。     

基于PIC单片机的智能漏电保护器

针对通用型漏电保护器在二级漏电保护系统中,作为第一级保护器使用时存在的漏电流显示、报警漏电流阀值设定、动作时间设定、报警指示和读取报警漏电流历史数据等功能方面存在的不足,提出并设计了以PIC单片机为核心,由漏电检测电路、信号调理电路、数值显示电路、报警指示电路、按键电路和脱扣器线圈控制电路等组成的一种智能漏电保护器.     

高灵敏度电流测量

<正> 高灵敏度电流测量,在半导体器件反向漏电流检测、化学仪表和核物理电子学等领域有着极重要的应用,它直接影响着有关仪器的水平。运算放大器在电流测量领域已经得到了广泛的应用。前置级采用改进型达林顿连接的超β差分对管的运放测量电流的灵敏度可以达到5×10~(-13)A。本文将要报告,采用高阻抗低漂移结型场效应管为输入级的运放,其测量电流的极限灵敏度可达到5×10~(-15)A。采用MOS场效     

诊断信号法漏电保护系统的研究与应用

主要介绍了煤矿井下高压供电网络发生单相接地时容性电流的分布规律和特点,以及煤矿井下电网漏电保护的基本原理和应用现状,总结了目前技术存在的弊端。结合现场工程实际,提出了一种新型的煤矿井下高压电网漏电保护方法。该方法采用注入诊断电流信号和开关内部保护器,通过算法分散检测诊断信号,判断和保护电网故障线路,弥补了传统漏电保护通过零序电流判断接地线路的缺陷,提高了煤矿井下高压漏电保护的准确度以及煤矿井下供电的安全性。     

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。