多功能电流电换器

本文介绍了一种既可以做Ｖ／Ｉ变换又可以做Ｉ／Ｉ变换的电路,推导出变换公式,提供了电路参数选择的准则和调试方法。     

无线通信中频线路窄带临界调试法及其应用

无线通信线路临界调试法是本实验中心在长期的工程设计、制作、调试实践中总结出来的一种电路增益调试方法,它充分利用了无线通信线路的属性,挖掘放大电路的潜在能力,最大化地放大了输入的高频信号,简化了后续电路。本文摘取本实验中心作品"电磁波辐射污染自动跟踪与预警装置"中的中频放大电路为例进行分析,着重阐述中频电路的原理SCH设计及印制板PCB设计技巧、Y参数等效与分析;详细描述了临界中频调试法的调试全过程,它改变了传统高频电子线路的调试理念、调试模式,提出窄带临界调试方法并付诸实施,不仅提高了放大器的放大能力,而且也提高了电路的抗干扰能力,用此方法指导学生进行科技创新,曾在全国"大学生电子竞赛"、"挑战杯"等项目竞赛中取得佳绩。     

智能无线供电装置的研究与制作

根据电磁共振原理,采用常用电子元器件设计一智能无线供电装置. 以射频电路、接收检测与控制电路为核心, 自动检测有无负载,根据检测有无负载的结果,控制发射电路是待机还是正常工作,以此提高电源利用率.通过反复修改元器件参数与调试,实验作品的发射线圈与接收线圈相距200mm范围内,能点亮1 6个10mA的LED灯.文中介绍了该方案的电路原理图及工作原理,安装调试方法,总结了制作过程中需要注意的问题.     

光接收机前置放大器的设计

介绍一种用于电场探测仪中的光接收机前置放大器,给出了线路组成、电路分析以及调试方法.     

一种程控增益宽带射频放大器的设计与实现

程控宽带射频放大器是基于同步脉冲转移原理的有线电视机顶盒的最重要的电路之一.介绍了一种程控射频宽带射频电路的设计与实现方法.该电路设计巧妙,原理简单,生产、调试与维修都非常方便.实践证明该电路工作良好,性能优良.     

心率模拟信号处理电路的仿真研究和设计

为保证基于FPGA数字心率计设计的性能,心率信号处理的模拟电路设计至关重要,由于外围电路存在噪声干扰,如何优化设计该电路,以有效地提取心率信号是传统设计的难点.利用Multisim仿真,可以很好地解决传统设计方法难以实现的电路优化设计.Multisim仿真把传统的硬件设计、调试、仿真集成在一个软件环境下,边设计边修改边调试,经过不断地参数设计和电路的调试,将心率模拟信号处理电路分为前级、中级和末级多级放大,低通、高通和陷波多级滤波,最终经过整形得到心率的数字信号.实践表明,改进电路有效地去除噪声,可提取正确心率信号,达到了理想的设计效果.证明仿真设计为信号处理电路提供了一个有效手段.     

基于UCC3809及UC3909的电动自行车充电器

介绍了蓄电池充放电机理、UCC3809及UC3909的内部结构以及基于UCC3809及UC3909设计的一种高性能充电器的电路原理、参数确定及整机调试过程。并提出了一种以绢流充电方式消除电池极板硫化现象的方法。     

FM-SCA射频接收系统二本振电路的设计与分析

综合分析FM-SCA射频接收中二本振电路.该二本振电路采用了MC3374内部振荡电路.文中采用理论分析、SPICE模拟及实际调试相结合的方法,确定振荡电路的结构及其振荡电路的元器件参数.经生产实践证明,该电路满足易起振、振荡频率稳定、振荡幅度高等条件.     

基于硅三极管的测温电路 工作原理分析及应用

惯导系统是精确制导武器中不可或缺的重要组成部分.在战术级或小型化产品上通常要对每个产品进行单独温度误差补偿等措施以抑制环境温度的影响.因此在生产线上,需要对光纤陀螺惯导系统的测温部件进行专门的标定,通过调整环节使其与基准温度源的误差保持在一定的要求范围内.通过对测温电路的分析,提出来一种测温电路调试方法,对三温度点测试法得到的测试数据进行线性拟合,结合调试电阻对拟合曲线的斜率和截距的影响关系调整调试电阻的大小,即可快速完成测温电路的调试.实际测试证明该方法是可行的.     

AM/FM立体声收音机单片集成电路KA2293

介绍AM/FM立体声收音机单片集成电路 KA2293的内部结构、电性能参数及其应用电路与调试.该电路内含立体声解码器.具有一定的新颖性.     

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。     

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.