基于FPGA的PCIe总线接口的DMA控制器的设计

采用Altera公司FPGA提供的PCIe PHY IP和Synopsys公司提供的PCIe Core IP提出了一种PCIe总线接口的DMA控制器的实现方法,并搭建了4通道的PCIe传输系统。利用Synopsys VIP验证环境对系统进行了仿真验证,利用Altera Stratix V EX系列FPGA搭建平台进行了实际传输验证,验证了数据读写的正确性,在进行DMA读写事务操作时总线带宽峰值分别达到了1 547 MB/s和1 607 MB/s,能满足大部分实际应用中对数据传输的速率要求。     

基于PCIe总线的多路实时传输系统设计

针对多路图像数据的传输及处理带宽需求,使用Virtex-6 FPGA设计实现了基于PCIe总线的多路实时传输系统。该系统主要包括仲裁控制多设备对DDR3的访问,采用PCIe Bus Master DMA方式实现与PC之间的高速传输,以及对全双工传输过程中存在的拥堵问题进行优化。实验结果表明,该实时传输系统最高的传输速率可以达到单工写1 632 MB/s,读1 557 MB/s,全双工写1 478 MB/s,读1 439 MB/s,并且性能稳定,完全满足多路图像采集后的高速传输处理需求。     

基于FPGA的PXIe总线DMA设计与实现

PXIe总线标准是PCIe总线的工业扩展.通过对基于FPGA的PCIe IP Core的研究,在FPGA上实现了PXIe总线,并提出了PXIe总线DMA的新设计.从DMA作为总线主设备和总线从设备两种功能出发,设计了两个DMA通道,分别完成数据读和包的传输.并且设计了将小块离散数据整合成连续数据块的优化算法,使四通道PXIe能达到500MB/s的读写速度.经过实际信号的测试,验证了DMA模式数据传输的正确性及传输带宽.该系统可以满足高速PXIe总线传输带宽的要求,在工程应用中有显著的参考价值.     

基于FPGA的PCIe总线DMA控制器的设计与验证

PCIe总线是为了解决高速率高带宽提出的新一代总线,随着处理器技术的发展,在互连领域中,PCIe总线的使用越来越多;为了实现上位机与FPGA之间的高速数据交换,基于FPGA设计了能够高速传输数据的DMA控制器,本设计的验证是基于北京航天测控公司开发的6槽机箱、嵌入式控制器(基于PCIe总线)、以及数字I/O模块;设计实现了嵌入式控制器与数字I/O模块之间的数据传输,并且通过了验证,证明了DMA控制器功能的正确性;加入DMA控制器后,写数据传输速率达到610MB/s,提高到了原来的7倍;读数据传输速率达到492MB/s,提高到原来的11倍,满足系统的设计要求;该控制器在大带宽的数据传输中有广泛的应用。     

基于FPGA的PCIe总线接口的DMA传输设计

串行的PCIe接口是第3代I/O互连标准,具有高速率和高带宽等特点,克服了传统PCI总线在系统带宽、传输速度等方面的固有缺陷,具有很好的应用前景;本设计使用Altera公司FPGA提供的PCIe IP硬核提出了一种实现PCIe接口的方法,并针对其高带宽的优势,设计了PCIe总线的高速DMA数据传输方案;利用自行开发的PCIe接口板,在QuartusⅡ11.0开发环境下进行SignalTapⅡ在线仿真并实际传输验证,DMA传输带宽在500MB/s以上,表明该设计方案可以满足PCIe总线传输带宽的要求。     

基于PCIE的高速光纤图像实时采集系统设计

利用PCI Express(PCIE)总线及DMA数据传输技术,设计光纤图像实时采集系统.利用FPGA中的PCIE硬核实现了PCIE总线的DMA传输,同时介绍了整个采集系统的数据流和光纤接口模块的设计.测试结果表明,系统DMA数据传输速度可达到138 MB/s,完全满足高速光纤图像实时采集的需要.     

基于PCIe的多路传输系统的DMA控制器设计

为了避免PCIe传输过程中PIO写延时、主机与嵌入式处理系统交互次数过多等问题对于传输带宽的影响,设计了一种基于命令缓冲机制的直接存储访问（DMA）控制器以提高传输带宽利用率。采用FPGA端内部设置命令缓冲区的方式,使得DMA控制器可以缓存PC端的数据传输请求,FPGA根据自身需求动态地访问PC端存储空间,增强了传输灵活性;同时,提出一种动态拼接的DMA调度方法,通过合并相邻存储区访问请求的方式,进一步减少主机与硬件的交互次数和中断产生次数。系统传输速率测试实验中,DMA写最高速率可达1631 MB/s,DMA读最高速率可达1582 MB/s,带宽最大值可达PCIe总线理论带宽值的85.4%;与传统PIO方式的DMA传输方法相比,DMA读带宽提升58%,DMA写带宽提升36%。实验结果表明,本设计能够有效提升DMA传输效率,明显优于PIO方式。     

UM-BUS总线测试系统中PCIe的设计与实现

UM-BUS总线单通道理论带宽可达200 Mb/s,采用16通道并发传输时,理论带宽可达400 MB/s,其测试系统需要在数据采集终端与PC之间建立不低于此带宽的通信通道。PCIe1.1采用4通道传输时理论带宽可达1 GB/s,满足了UM-BUS总线测试系统的传输带宽需求,由此设计实现了UM-BUS总线测试系统的PCIe1.1 x4链路通道的应用方案,给出了基于FPGA的PCIe总线的BMD传输方案。测试结果表明,该方案实际传输速度可达550 MB/s,满足UM-BUS总线测试系统的带宽需求。     

PCI9054的PCI接口通用收发模块设计

为满足电子测量数据采集系统的高速化和通用化要求,提出了一种基于PCI9054的PCI接口通用收发模块设计.结合PCI9054的物理架构和DMA突发模式工作原理,详细设计出该通用收发模块的核心组成部分,硬件采用PCI9054作为PCI桥接芯片,以Zynq系列FPGA(xc7z100ffg900-2)作为本地总线控制器.解析PCI9054上电配置方法,用FPGA搭建本地总线控制逻辑,对DMA突发读进行时序分析,突发速度可达100 MB/s.     

基于PCIe的DMA传输在UM-BUS测试系统中的设计与应用

动态可重构高速串行总线(UM-BUS)是一种利用多通道并发冗余的方式来实现总线动态容错的高速串行总线。它的测试系统可以实现对总线的通信过程进行监测、存储与分析。由于测试系统需要在数据采集终端与PC之间建立高带宽的通信通道,设计了UM-BUS总线测试系统的PCIe2.0 x1通道的应用方案,设计并实现了基于FPGA的PCIe总线DMA数据传输方案。实验测试结果表明,实际传输速度可以稳定达到200 MB/s以上,完全满足总线测试系统中对数据传输速率的要求。     

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。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。