信号处理系统高性能网络关键技术的研究

新型通用嵌入式信号处理系统是基于分组交换网络实现的。在嵌入式系统中,其中一个关键的问题是设计高性能和高可靠性的分组网络,解决多个处理器高速互连,进一步提高信号处理系统的整体性能。RapidIO协议是商业联盟协会为了解决嵌入式系统高速互连的问题于2001年3月提出的,该文根据协议的要求和应用范围,以及信号处理系统的特点,将该协议用于解决信号处理系统高速互连的问题,提出了一种能适用于RapidIO分组交换网络不同拓扑结构的路由策略,最后运用概率模型对此分组交换网络的一些性能进行了比较详细的分析。该文通过对实现RapidIO协议关键技术的研究和对系统性能的分析,对建立基于RapidIO协议的通用高速信号处理系统具有重要的意义。     

基于FPGA实现的高速串行交换模块实现方法研究

采用Xlinx公司的Virtex5系列FPGA设计了一个用于多种高速串行协议的数据交换模块,并解决了该模块实现中的关键问题。该交换模块实现4X模式RapidIO协议与4X模式PCI Express协议之间的数据交换,以及自定义光纤协议与4X模式PCIExpress协议之间的数据交换,实现了单字读写以及DMA操作,并提供高速稳定的传输带宽。     

基于RapidIO的多DSP互联仿真实现

RapidIO协议作为数据通信协议之一在嵌入式系统开发中具有重要作用, 适合短距离, 需要多处理单元合作的应用场景, 例如多DSP构成的板卡系统. BWDSP芯片作为一款高性能数字信号处理器, 其丰富的计算资源在雷达信号处理等领域具有重要潜力. 硬件设计开发中, 直接采用已有数据通信协议很难适配具体硬件资源导致最终产品的数据传输性能较低. 因此需要结合具体硬件模型, 进行数据通信交换模型仿真建模设计, 提高数据传输效率. 本文首先介绍了RapidIO协议和BWDSP体系架构, 然后设计了基于SystemC语言的串行RapidIO交换模型, 最后设计实现了BWDSP虚拟平台. 本文设计的BWDSP虚拟平台功能符合实际RapidIO协议标准, 对硬件产品开发具有一定指导意义.     

基于PCI-Express和Aurora协议高速光纤通信板卡的实现

介绍了一种基于单片FPGA的高速光纤通信通信板卡,利用Aurora协议支持光纤传输,采用DMA控制逻辑通过PCI—Express接口与主机交换数据,着重阐述了板卡各个功能逻辑实现。实际的测试数据表明该系统具有高带宽、可扩展的特点。     

基于PCI Express总线的高速光纤接口卡的设计与实现

针对高速数据采集和远程传输的需求,提出了一种基于PCI Express总线的高速光纤接口卡的设计方案和功能实现。该接口卡基于单片Virtex-5 FPGA,采用PCI Express总线架构,以LocalL-ink做为内部链路,并利用Aurora协议实现远距离光纤传输。通过采用DMA的数据传输方式,接口卡的传输速率达到了700 Mb/s。     

C645x的串行RapidIO总线通信系统设计

以多片C645xDSP为应用对象,介绍DSP之间的串行RapidIO总线通信方式。详述串行RapidlO的结构层次、硬件设计和软件设计方法。在DSP的数字信号处理功能基础上应用串行RapidIO,使得数据传输速率达到10Gbps,从而实现语音、视频和数据的同时传输,满足高速数据传输系统的需求。     

基于FPGA的RapidIO总线接口设计与实现技术

为了适应新的数字信号处理技术的发展,采用FPGA实现技术设计了串行RapidIO高速串行传输接口,实现了DSP与FPGA之间、FPGA与FPGA之间的高速数据传输,详细介绍了本地端点设备访问和远端设备访问的时序设计过程。对RapidIO总线的性能指标进行了测试,试验表明,在1lane、全双工模式下,数据传输速率可达243MB/S,突破了以前DSP的外部接口总线的传输速度瓶颈。     

基于RapidIO的实时CORBA中间件实现

为了解决CORBA传统传输协议TCP/IP的时延不确定问题,提出了使用基于点对点的包交换RapidIO协议来替代TCP/IP的方法,研究了CORBA的可插拔传输协议框架,从而实现了CORBA报文在RapidIO总线上的传输。测试结果显示,基于RapidIO的CORBA实时性优于基于TCP/IP的CORBA。     

基于Aurora协议的高速通信技术的研究

介绍了基于模块化方法在FPGA上实现高速通信的设计方案。系统在Aurora协议下采用高速串行收发器Rocket I/O,解决了不同端口收发时钟补偿带来的数据丢失问题,并结合SFP光模块对高速AD采样信号进行有效的传输。实验证明了方案的可行性,其对提高雷达信号处理带宽、改进雷达的探测性能具有较大的意义。     

片间高速图像传输系统的设计与实现

针对图像采集与处理系统研发中的现场可编程门阵列(FPGA)之间的高速图像数据传输问题,设计了一种全双工、高吞吐率、高稳定性和高抗干扰能力的高速图像数据传输方案。设计的片间高速图像传输系统提供了通用的图像传输接口,可兼容不同的数据位宽和用户时钟频率。高速图像传输模块分为协议层和物理层。协议层包括跨时钟域电路和CXP图像传输协议编译码电路,完成跨时钟域和图像数据流编译码处理;物理层基于Aurora 8B/10B core,完成数据流的串并转换以及多通道绑定等处理,并采用GTH收发器实现高速串行数据的收发。仿真测试表明,图像数据传输正确,图像数据流同步时钟最高可达250 MHz,传输位宽达128 bit,最高吞吐率可达32 Gbit/s,平均吞吐率为20 Gbit/s,并且还有很大的提升潜力。该高速图像传输系统能够实现高吞吐率、高抗干扰、低错误率的图像数据传输,有助于各种不同视觉测量系统和图像处理系统的开发,具有广泛的应用价值。     

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.