基于FPGA的BLVDS高速通信总线设计

测试总线是测试系统中的一个重要环节,是准确传输信号的关键。详细介绍了LVDS与BLVDS技术,在此基础上论述了BLVDS总线布置设计、PCB布线设计、数据格式设计及通信背板设计,并提出了一种基于FPGA的BLVDS总线设计,采用Verilog HDL实现FPGA内部逻辑电路设计,FPGA完成BLVDS总线上数据的接收、发送,以及数据的缓存。实验结果表明,该总线通信速度快、稳定、可靠。     

基于BLVDS的控制系统通讯总线的硬件设计与实现

为了满足控制系统对本地通讯总线实时性、可靠性及兼容性越来越高的要求,研究了BLVDS总线的在高速、低噪声、支持多点应用和可变负载等方面的优势,设计了一种基于BLVDS电平的控制系统高速总线,从拓扑结构、端接匹配、PCB设计要点等总线硬件关键技术角度进行了详细的分析和设计,并在128Mbps的通讯速率下对各种情况下总线的性能进行测试。结果表明,基于BLVDS的高速总线通讯准确且稳定可靠,具有一定的应用价值。     

ARINC659总线测试方法研究

ARINC659总线是一个具有总线传输时间确定性的多节点串行通信总线,为了保障ARINC659总线系统在通信过程中的高容错性、高冗余度、高完整性和高可靠性,对其进行充分测试是十分必要的,能确保ARINC659总线系统安全可靠地使用。搭建了ARINC659总线测试平台,在此基础上从物理层和数据链路层两方面对ARINC659总线的测试进行了分析和研究,对提高ARINC659总线系统的可靠性具有重要意义。     

基于FPGA的高速模拟信号采集卡设计

测试系统中的信号采集是系统的一个重要环节;文章提出了一种基于FPGA的高速模拟信号采集卡,采用Verilog HDL实现FPGA内部逻辑电路设计,采用AD7938实现ADC采样模块;总线选择BLVDS,FPGA完成BLVDS总线上数据的接收、发送以及数据的缓存,上位机指令和板卡反馈数据依照Modbus协议进行传输,C8051F120完成对FPGA内部BLVDS接收电路缓存数据的读取,根据上位机指令对AD7938控制寄存器以及影子寄存器进行控制,并启动BLVDS驱动电路完成数据的发送;实验结果表明:通信速度快、稳定、可靠,电压采集的结果控制在±0.10V允许范围内。     

基于89C51和SJA1000的CAN通信方法研究

介绍CAN总线基本原理和CAN总线通信的基本结构,给出了一种由MCU、总线控制器和CAN控制器构成的通信系统,进行了通信节点的软硬件设计,并对CAN总线系统进行了网络负载和实时性分析。分析结果表明,系统具有较好的可靠性和实时性,适用于中高速工业数据通信场合。     

一种简单实用的RS-485总线光电隔离中继器设计

RS-485总线是计算机测控领域广泛采用一种现场总线形式,其发送和接收数据均采用双端差分信号,可以有效地克服共模干扰,有较高的数据传输速率和传输距离。在实际应用中由于在双绞线上的电平损耗,RS-485总线标准通信的最大传输距离是1200米(4000英尺),并且总线系统只允许同时存在一定数量的通信节点,如果要传输更远的距离或挂更多的通信节点就必须使用中继器。目前市售的RS-485中继器一般采用单片机或其他可编程器件控制,价格较高且对通信参数有一定的要求,使用范围有限。本文通过对常用的RS-485总线接口器件MAX487的工     

基于FPGA的智能化波形发生板卡设计

测试系统中的信号源是系统的一个重要环节,是准确反馈被测部件各项性能参数的关键.提出了一种基于FPGA的波形发生板卡,采用Verilog HDL实现FPGA内部逻辑电路设计,采用DDS算法实现波形频率.总线选择BLVDS,FPGA完成BLVDS总线上数据的接收、发送,以及数据的缓存,上位机指令和板卡反馈数据依照Modl3...     

基于CAN总线驱动器和异步收发器的通信网络

分析和对比了RS485和CAN总线技术,指出RS485总线具有成本低和开发简单、而CAN总线具有可靠性高和通信距离远的特点;虽然它们的总线信号逻辑不同,但是它们与单片机的接口数字逻辑信号相同;在此基础上,结合两者的优点设计了基于CAN总线驱动器和异步收发器的通信网络,给出了基于该通信网络的一种应用形式;在Modbus主从式通信方式基础上,设计了新的适合多主通信方式的数据包格式,给出了发送节点的通信活动图,并详细陈述了基于有限状态机的通信流程和编程方法;该通信网络可以用于传统RS485总线很难满足要求、需要CAN总线的性能而又要求价格比较低的场合。     

智能型RS485总线接口设计

控制领域中的分布式监控系统具有节点多、传输距离远以及现场工作条件恶劣等特点,因此需要一种能够支持多节点、远距离通信以及传输信号安全可靠的总线构成网络。结合RS485总线在实际监控系统中的应用,文章设计出了满足上述要求的智能型RS485总线接口,并在实际使用中收到了较好效果。     

AT90CAN128的CAN多节点总线同步通信

针对CAN总线多节点的同步性应用,介绍了两种滤波方式,实现了基于AVR单片机ATg0CAN128的CAN总线多节点同步通信。利用CAN总线的点对点、点对多点和广播通信方式以及其特有的报文滤波和非破坏性总线仲裁技术,对多节点的同步性进行探讨,且接入方式简易。     

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     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

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。