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。     

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。     

基于FPGA的USB3.0高清视频传输系统的设计

针对USB2. 0接口由于速率和带宽不够而无法满足高清视频实时传输的问题,提出了一种基于FPGA的USB3.0高清视频传输系统方案,并从吞吐速率角度分析了方案的可行性;采用SDRAM缓存视频数据和在视频流中插入帧同步码的方法,保证视频图像的完整和像素对齐;对系统进行了模拟测试和实际高清视频传输测试,测试结果表明:该系统实现了高清视频的实时传输,以320 MB/s的速度稳定传输视频数据。     

基于FPGA的USB3.0通信架构设计与实现

针对USB设备与主机通信存在的带宽瓶颈问题,设计一款基于USB3.0协议的高速通信架构,为嵌入式设备与PC之间的USB数据高速通信提供一种可选方案。本设计采用Cypress的EZ-USB FX3芯片作为USB的外设控制器,以FPGA作为整个硬件系统的主控芯片,通过对FPGA硬件系统进行设计,对设备固件进行设计与调优,该架构支持USB 2.0/3.0接口自适应,能够实现主机、国产嵌入式CPU、SRAM之间的两两可变帧长通信,硬件传输速度达到360 MB/s,数据连续传输速度达到148 MB/s。     

USB总线高速数据采集系统的设计误区及解决方案

USB总线的实际传输速率与理论传输速率相差甚远,且不能保证其稳定性,一般在15MB/s～25MB/s左右;然而很多设计者在设计基于USB总线的高速数据采集系统时却并没有考虑到这一点,所设计的系统建立在USB具有稳定的高速率的基础上,必然会造成缓存溢出而丢失数据;指出了这类系统的设计误区,在分析了高速采集数据特点的基础上,提出了一种基于数据抽取、消除零空位、数据压缩的整套解决方案;在给出的实例中,该方案具有19:1的压缩比,其USB总线传输速率约为4.5MB/s,适用于USB总线实际传输带宽.     

争分夺秒还是多此一举U盘/SD卡提速大作战

打破USB2.0接口常规传输速度 并不是所有的台式机和笔记本都配备有USB3.0接口,尤其是购机较早的台式机用户和购买低价入门级笔记本的用户,USB3.0接口离他们还有些距离.不过连续大幅度降价让USB3.0接口U盘迅速得以普及,这使得不少用户拿着USB3.0存储设备,却无法享受高速数据传输的快感. 其实USB2.0接口的理论数据传输速度可达480Mbps (60MB/s),不过由于受到各种系统协议(Bulk-Only Transport(BOT)协议)和编码方式(NRZI编码方式)的限制,USB2.0接口实际传输速度通常被限制在30MB/s左右,仅为理论最高传输速度的一半.我们无法改变USB传输底层NRZI编码方式,但可以通过修改Bulk-Only Transport(BOT)协议区块大小,增加USB带宽利用率,提升USB2.0接口常规传输速度.     

新型总线中并行CRC算法的设计与实现

为了对动态可重构高速串行总线UM-BUS进行差错控制,提出了一种用于新型总线数据校验的四通道并行CRC算法.根据UM-BUS的多通道并发通信方式和通道动态组织特点,采用四体FIFO进行数据缓冲存储,并设计了满足总线特点的四通道并行CRC编解码器.在此基础上,给出了它的FPGA实现方案和仿真结果.该并行CRC编解码器,可实时计算总线通信数据的CRC校验码,已成功的应用于动态可重构高速串行总线系统中,实现对突发错误的实时检测,通信速率达到100Mbps/通道.     

基于USB3.0的高速读数盒设计

针对测试系统中USB2.O接口已不能满足当代测试速度需求,提出一种基于USB3.O和FPGA的高速读数的解决方案;该方案以FPGA为核心控制器,EZ-USB FX3被配置成Slave Fifo从模式;通过对DMA通道和GPIFⅡ接口优化设计以实现指令的下传和数据的高速上传;经实际传输测试,该读数盒能在传输数率高达228 MB/s时依然能保持正确无误的高速传输。     

UM-BUS总线传输系统的建模与仿真

UM-BUS(动态可重构高速串行总线)是一种基于故障实时检测和动态重构的新型多通道高速串行总线.UM-BUS总线的传输介质为屏蔽双绞线,传输通道采用MLVDS(TIA/EIA-899-2002)信号传送方式,能够支持多个节点设备直接连接.基于传输线理论,采用Hyperlynx建立了UM-BUS总线物理线路的电阻隔离型、电容隔离型、阻容隔离型3种传输模型,并对仿真眼图及实测眼图进行了分析,确定了UM-BUS总线物理链路模型,为进一步研究UM-BUS总线传输系统提供了支持.     

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。     

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。     

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.     

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。     

基于AD9626的模拟信号采集存储卡设计

自然界的绝大部分信号都是以模拟的形式存在,因此模拟信号的采集转换存储在数字时代十分关键。文章讨论了在雷达信号处理领域基于AD9626的AD采集存储卡的设计原理、硬件结构和程序设计与芯片配置等问题,为今后相关领域的研究提供了可参考的方案。     

A human-computer interface for non-computer specialists

The COM teleconferencing system was designed to be easy to use for both beginners and people with much computer experience. A number of design choices in organizing the human-computer interface were considered very carefully. These design problems are not unique for teleconferencing applications, but will appear in many other developments of human-computer interfaces for non-computer specialists. This report discusses naming conventions, menu format, user commands, help facility and the treatment of ‘type ahead’ from the users.     

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.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

Call for papers Special issue on Modeling and control technologies for civil,energy,and power systems

正The control of civil,energy,and power systems presents significant new challenges for modeling and control theory.The purpose of this special issue is to provide a forum for researchers and practical engineers to discuss the recent advances in modeling and control technology development for civil,energy,and power systems.Prospective authors are invited to submit their original contributions with the focus on theory or applications of modeling,control     

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正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate and promote academic exchange between Chinese and foreign scientists everywhere.