汽车发动机转速信号模拟器设计

介绍一种简单、便携、多功能的发动机转速信号模拟器,采用PWM信号逼近的方法生成幅值随发动机转速变化的磁电信号,采用输出比较的方式输出霍尔信号。该模拟器可以方便地设定发动机参数和实时在线修改发动机转速,并能够实时显示。实验结果表明,该模拟器具有信号精度高、发动机转速范围大的特点。     

基于双模控制的直流力矩发动机控制系统设计

针对航控发电机对控制直流力矩发动机性能要求,在分析传统控制系统故障目标精准度定位速度慢基础上,提出了基于双模控制的直流力矩发动机控制系统设计。根据直流力矩发动机双模控制原理,设计系统总体结构。通过转速信号模拟器产生数字信号,在串行A/D转换电路中引入MAX144型号可编程逻辑器件,改善信号转换精准度。使用碳化硅（Sic）智能功率模块,为硬件设备提供合适膨胀匹配系数,改善能耗问题。选择TMS320F28335PGFA型号数字信号处理器,可将信号转换为数字形式。控制电源开关频率在50-100kHz范围内,具有一定抗干扰能力。添加电流环,为发动机提供相对恒定电流。在MPLABI_DE集成开发环境下,采用双模控制磁场补偿方式调试电流环控制程序,选择大小适中的通电电流,设置转子预定位程序,根据系统主程序流程,完成发动机控制系统设计。由试验结果可知,该系统在故障目标精准度定位速度上最快可达到0.05个/s,大大增强了系统鲁棒性能。     

基于EDA技术的频率计系统研究与设计

本文主要研究介绍了一种基于EDA技术的频率计系统,系统通过采用硬件语言VHDL自顶向下的设计方法来设计实现频率显示功能,其中频率的显示控制电路和频率的测量电路是设计的核心内容,系统的辅助电路多通过硬件电路来实现完成。基于EDA技术的频率计系统主要是由基准频率信号电路、显示控制和频率测量电路、显示输出电路、电源电路构成,采用EP2C8Q208C8型号的FPGA芯片作为系统的核心电路。     

基于DSP的交流电机伺服控制器设计

对基于DSP交流异步电机伺服控制系统进行硬件设计,介绍了双闭环伺服电机硬件电路的设计,并主要介绍DSP外围电路的设计及器件选型,包括整流逆变电路、能耗制动电路、电流检测电路、光电编码电路、温度检测电路以及电流保护电路.通过温度和电流检测电路对电机的运行状态进行实时保护;通过光电编码电路可以对增量式光电编码器信号进行信号变换;DSP对光电编码器的信号进行解码,并通过换算关系进行电机转速和位置的计算.本系统在基于电流环、速度环检测的基础上对交流电机进行精确的转速控制.     

发动机转速信号采集

介绍采集航空发动机非连续转速信号的波形转换电路、可编程逻辑电路设计,以及将测频法和测周法结合起来进行频率信号采集的软件设计方法,以实现对发动机转速状态的监控.     

航空涡轴发动机转速与扭矩信号的仿真研究

针对航空涡轴发动机转速与扭矩信号的仿真问题,分析检测发动机转速与扭矩的原理以及信号特性,创新提出在ZYNQ平台上实现仿真信号的合成方法。采用基于直接频率合成器的设计,计算分辨率、数据位宽、无杂散动态范围等参数以及分析对精度的影响。为保证实时性要求,依托片上高速数字总线AXI4控制频率和相位的设置,产生两路同步数字正弦信号,通过比较、滤波与合成实现仿真信号的输出。在硬件方面,采用数模转换与信号调理电路,在保证各项性能指标前提下,优化了器件选型,同时增加输出接口保护,避免因静电或误操作引起的故障。实际使用情况表明,仿真信号精度高、运行稳定可靠,目前已被应用到多个航空涡轴发动机的实验项目。     

基于PIC16F73的汽车仪表系统设计与分析

24LC02B是Microchp公司的EEPROM芯片。单片机16F73对输入信号频率及电压进行测量计算处理,设计实用的汽车仪表系统．可以实现包括转速信号、车速信号、油量信号、水温信号等并在相应的仪表盘进行显示,介绍硬件电路与软件编写,提供电路原理图．给出了软件的总体设计,特别是对数据计算处理部分的程序编写做了详细分析。     

车辆智能发动机转速测量系统设计与实现

在对车辆发动机转速的测量过程中,存在着测量时间与测量精度的矛盾.文中提出了一种动态调整测量次数的频率测量法,合理地解决了这个矛盾,使得测量系统能在满足实时性的要求的同时,尽可能获得高精度的发动机转速测量.该方法合理地利用常用单片机系统的两个定时/计数器作为测量时标信号及发动机转数计数,使得系统的硬件电路简单、可靠.同时还提供了对该设计的实现方法.     

航空发动机台架点测量仪研制

介绍了基于89C51单片机的航空发动机台架点测量仪设计，详细描述了信号调理电路的设计思路及实现途径，系统采用软件中断后台采集发动机转速信号并总体阐述了硬件、软件设计特点，部队使用表明测量仪的推广应用具有重大的军事经济效益。     

基于单片机的信号发生器设计

以单片机为核心控制器,结合D/A 转换、LCD1602 显示、程控放大器,设计输出频率、幅度可调的正弦波、方波 和三角波信号发生器,对系统主要硬件电路和软件进行设计。经实验测试,系统实现了各波产生、显示,信号频率、幅度可调等 功能,频率和幅度误差都是5%以内,波形质量较好。系统电路简单、体积小、成本低、精度较高、工作稳定和使用方便直观,具 有广泛的应用前景。     

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.