面向VFD显示的工业称重仪表开关电源设计

针对VFD显示的工业称重仪表供电的需求,该文设计一种开关电源。该电源产生基本的多路输出,其中一路为反馈确保电压稳定,各路输出通过电路转换得到更为精确的电压,不仅为工业称重仪表的主控板、设定显示板安全和稳定地供电,而且解决了传统VFD交流供电体积大的问题。实验结果表明,所设计开关电源性能指标高,是可靠合理、高效的电源。     

称重仪表的模块化及网络化设计

针对称重仪表的发展趋势,该文设计一种模块化、网络化的称重仪表。该仪表采用双处理器(MSP430F147结合AT89C52)实现模块化设计,包含模拟量采集与控制、VFD(真空荧光显示屏)显示、Ethernet接口、IO扩展及电源五个模块。其中Ethernet接口模块采用通用型串口以太网转换设备,方便仪表接入Internet。实验测试表明该仪表运行稳定可靠,使用方便灵活,功能强大多样。     

基于移动基站蓄电池组的开关电源设计

移动基站中的备用电源是由24节蓄电池(每节2V)组成,在电池充电或放电的过程中,蓄电池组的整组电压会发生变化。本文提出了一种以移动基站蓄电池组为供电电源的开关电源设计,其输入电压允许蓄电池组的整组电压在较宽的范围内波动。该开关电源基于UC3842的调控电路,结合单端反激变换、RCD箝位等电路,可稳定输出较低纹波系数的12V、5V和3.3V的供电电源。     

应用于手持设备功率放大器的开关电源设计

提出了一种应用于TD-LTE信号手持设备功率放大器MRF9742的开关电源设计.该电源采用脉冲宽度调制的降压电路结构,采用包络跟踪技术,通过输入信号功率值来动态调节功率放大器的供电电压,与使用稳压电源供电的功率放大器相比,在不影响输出的条件下降低直流功耗,因此提高了功率放大器的功率附加效率.使用开关电源进行供电的功率放大器比使用稳压电源供电的功率放大器PAE提高了10％左右.故在手持设备中采用开关电源进行供电可以提高电源的使用效率,从而延长了手持设备的使用时间.     

智慧路灯控制系统的AC-DC电源设计

设计了一种应用于智慧路灯控制系统的双路输出AC-DC开关电源。文中介绍了所设计电源的电路构成、性能特点,详细分析了电压输出反馈控制原理和反激变压器的参数设计。应用实测结果表明,电源电路设计合理,该电源具有输出稳压性较好和输出电压品质高等优点。     

一种反激式双输出DC/DC变换器的设计与实现

针对市场上DC/DC开关电源高压输出时,输出电压纹波较大问题,介绍了一种±50 V双输出DC/DC开关电源的设计方法及测试结果。该电路采用电流控制型PWM控制芯片,工作于反激模式。输入输出通过光耦实现隔离。该DC/DC变换器具有带负载能力强、纹波低、输出电压高等特点,可为电子设备提供稳定的供电电压。     

基于UC3842反激式开关电源的设计

随着电力电子技术的飞速发展,电力电子设备与人们的工作、生活的关系日益密切,而电子设备都离不开可靠的电源.进入80年代计算机电源全面实现了开关电源化,率先完成计算机的电源换代,开关电源是利用现代电力电子技术,控制开关晶体管开通和关断的时间比率,维持稳定输出电压的一种电源,一般由PWM(脉冲宽度调制)控制IC和MOSFET构成.本文利用开关电源芯片UC3842设计制作一款新颖的单端反激式、宽电压输入范围、12V8A固定电压输出的96W开关稳压电源,适用于需要较大电流的直流场合(如对汽车电瓶充电).     

一种适用于交直流电源投切的监测装置

目前,很多电气系统以交流供电为主,同时以直流供电为辅助供电,当交流电断电时,直流辅助供电立刻投入供电,保障电气设备能正常工作。本文旨在设计一种适用于交直流电源投切的监测装置,监测电源状态。采用工频变压器将AC220V交流电压变压后双路输出,分别用于电源供电和电压信号差分AD采样。DC48V直流电压也分两路,分别用于电源供电和单端AD采样。设置交流电较于直流电优先为装置自身供电。本文的装置采用三点式校准,并设计显示单元显示交直流电压数值,电压高低限报警,超时自动进入休眠状态,实现高效节电。本文设计的适用于交直流电源投切的监测装置,可同时测量显示AC220V和DC48V,简单实用,性价比高,具有良好的电压监测、显示和报警功能,实际应用效果良好。     

基于TOPSwitch-GX芯片的开关电源设计

以电能质量监测装置的电源设计为例,介绍了一种基于TOPSwitch-GX芯片的多路输出开关电源的设计过程,并阐述了其工作原理。先利用单片开关电源设计软件PI Expert进行设计,然后再根据需要进行修正设计,从而提高电源的成功率和准确性。增加辅助反馈调节,可以提高开关电源的交叉负载调整率,同时将线性三端稳压器和开关电源相结合,可以提高电源输出的稳定性。实验结果表明该电源输出稳定,工作可靠。     

一款户外开关电源的设计、仿真与实验研究

根据目前主流笔记本电脑的电源适配器使用特性,设计了一款可应用于户外的开关电源.与传统适配器电源相比,该设计可以增强笔记本电脑的使用范围.利用开关电源仿真软件LTspiee Ⅳ进行仿真并对该款户外开关电源工作原理进行了详细分析.仿真与实验结果表明,在不同工作模式及不同带载情况下,该户外电源能输出纹波较小的稳定电压.     

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。