基于PCI-E总线的北斗导航授时卡Linux驱动设计

为提高Linux系统时间的精确度,设计了PCI-Express接口的北斗授时卡以及驱动程序;授时卡通过北斗卫星导航信息接收模块接收时间定位信息并输出至FPGA(Field－Programmable Gate Array,现场可编程门阵列),FPGA利用状态机检测出时间位置信息,并存入IP核创建的虚拟双口RAM中;当PCI-E驱动芯片接收到读取当前时间命令时,将虚拟双口RAM中时间数据传输至PCI-E总线供上位机读取;实验编写了Linux系统设备驱动程序,包括驱动的编译、加载,利用图形界面开发工具GTK+编写授时测试软件;打开授时测试软件,通过指令使能授时卡PCI-E驱动芯片硬件中断,检测到FPGA输出的中断信号,测试软件进去中断服务程序读取PCI-E总线上的时间信息,并在目标栏中显示;试验结果证明:在Ubuntu Kylin系统平台下授时测试软件运行稳定、界面简洁,且授时精度达到100纳秒。     

基于PCI-E总线的高速SDH信号存储系统

SDH光纤信号传输速率高、数据量大的特点是对该数据实时连续存储的主要难点:针对信号的这一特点,文章提出采用PCI-E总线作为数据传输总线,保证了数据存储的总线带宽;采用磁盘阵列作为数据存储的物理介质,解决了单个磁盘速率低容量小的问题;在此基础上给出了硬件结构配置和软件设计,实现了高速SDH信号的存储;测试结果表明,该系统运行稳定可靠,满足2.5Gb/sSDH信号的存储需求。     

基于SOPC的现场总线多通道实时温度采集系统设计

针对温度信号实时性和同步性有较高要求的工业生产领域,设计一种具有PROFIBUS现场总线接口的多通道实时温度采集系统。系统采用Nios II软核处理器实现SOPC设计;采用热电偶构建温度采集前端电路,利用FPGA实现模数转换器ADC以及其他外围设备工作的控制;采集的数据利用乒乓控制原理存储在高速FIFO中,从而实现数据的高速无缝缓存和处理,并通过PROFIBUS现场总线实现与上位机之间的高速数据通信。     

基于FPGA的VXI总线多功能模块设计

VXI总线多功能模块是某导弹自动驾驶仪VXI测试系统的关键模块,需要完成被测信号采集、特殊测试激励信号产生、频率测量和数字IO功能;文章首先简要介绍了模块的设计要求和总体设计;然后阐述了模块的各功能电路实现;接着重点论述了模块设计中采用扫描地址图谱实现多通道和量程动态切换、采用块传输实现VXI接口高速数据传输和采用RAM分时复用存储实现长时间连续数据采集等关键技术;应用这些技术研制的模块已应用于实际测试系统中,其性能良好,工作稳定;接口测试结果表明,模块的VXI接口设计极大地提高了数据传输速度。     

基于PCI总线的离散I/O接口板设计

介绍了一种基于PCI总线扩展功能的离散I/O接口系统的软硬件设计与实现方案。设计中,选择PCI 9052作为PCI总线接口芯片,利用CPLD作为板卡主控芯片实现地址译码和逻辑控制等功能,光耦和继电器分别作为输入输出隔离器件。该系统实现了控制采集24路光电耦合器输入信号和24路继电器输出信号的功能。应用表明,本接口板工作稳定,满足航电设备的输入输出要求。     

IIC总线和LVDS在高速数据传输接口电路中的应用研究

当前在高速数据系统中,LVDS接口已被广泛应用,为实现同系列设备之间的智能识别、自动握手以及LVDS高速数据链路通信质量的检测,利用FPGA的IO电路结构,设计一种模拟IIC总线协议电路,该IIC总线高效地实现设备之间的信息双向传递;同时利用FPGA内部丰富寄存器资源设计PRBS码型电路来检测LVDS接口芯片电路误码率;实际测试表明该多通道LVDS传输方式在2米长电缆连接能够实现数据的稳定、低误码率传输,并且在时钟频率为100 MHz时,数据传输速率高达4.68 Gb/s。     

机载多路DVI视频信号转换器设计

为了实现基于高速航电总线的多路DVI视频信号的采集及实时检测,提出了机载多路DVI视频信号转换器的设计方案;针对高速航电总线多路DVI视频信号速率高、实时性强的特点,完成了信号均衡、信号预加重及高速信号全交叉设计,采用单片机完成对转轮开关的采集、消抖和判断,通过配置相应寄存器完成测试DVI口的通道切换功能;实验结果表明,该机载多路DVI视频信号转换器稳定性好、可靠性高、实时性强,解决了高速航电总线多路DVI视频信号的检测难题,满足设计需求。     

基于虚拟仪器的航空发动机转子系统早期故障识别

简要介绍了虚拟仪器及PXI(PCI extensions for instrumentation)总线技术的发展状况及优越性,设计了基于PXI硬件系统及LabVIEW软件框架下的航空发动机转子早期故障识别系统.该系统可以实现多通道高速信号采集、数据预处理、信号分析、故障推理、诊断等功能,具有良好的人机交互特性.实验证明...     

水下传感器网络节点定位信号检测的设计

针对水下环境的特殊性和水声定位系统的要求,为降低检测水声定位信号的复杂度和硬件资源消耗,能够准确检测定位基站发射的水声定位信号,为目标基站的定位提供实时、快速的时延信息,根据水声定位信号的特点,采用码元匹配检波和编码定位信号相关的方法,确定水声定位信号的到达时间,并以FPGA为平台利用VHDL语言对水声定位信号的检测设...     

基于PCIe总线的数据采集卡设计与实现

为了实现对多路高速光信号采集,利用FPGA设计基于PCIe总线的数据采集系统;对PCIe总线低速Slave通道与高速DMA通道的关键算法进行了研究;首先,介绍了数据采集卡的硬件构成及基本工作原理,提出了PCIe总线算法需要解决的数据传输问题;然后,分析数据采集卡PCIe总线低速Slave通道和高速DMA通道原理以及实现的关键算法;通过Modelsim和SignalTap工具分别对数据传输算法进行功能验证和在线仿真;最后,将设计数据采集卡互联PCIe上位机进行实际测试;实验结果表明,本设计PCIe总线采用X4接口模式,数据传输系统的数据上传峰值速率为615.38 MB/s,可以满足稳定可靠、高带宽、模块化等要求。     

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.