基于DDR SDRAM的高速数据采集系统的设计

采用DDR SDRAM作为被采集数据的存储体,研究了DDR SDRAM在高速数据采集系统中的应用,分析了DDR SDRAM的工作模式,给出了一种基于DDR SDRAM的高速数据采集系统的设计框图,研究了高速、大容量存储体的设计方案.结合高速数据采集系统的设计要求,重点研究了一种DDR SDRAM控制器的FPGA实现方法,简要介绍了控制器设计中各个模块的功能,最后给出了读/写控制模块对DDR SDRAM的读操作仿真时序图.     

DDR SDRAM控制器中全数字延时锁定环的设计实现

介绍了一款可应用于DDR SDRAM控制器的基于标准单元的全数字延时锁定环(DLL)。该DLL可集成性和工艺兼容性好,可以减少DLL的设计时间和设计复杂度,非常适合系统级芯片使用。该设计采用0.18um CMOS数字工艺实现最终版图,工作频率范围达到200MHz至400MHz,无谐波锁定出错,且闭环特性可以跟踪工艺、电压、温度(PVT)变化。仿真结果表明该设计能够产生DDR SDRAM控制器规范所要求的一段固定延时(tSD)来保证DDR SDRAM控制器正确捕获存储器输出数据(DQ)。     

基于FPGA内嵌入式处理器的二维脉冲压缩

设计一个利用现场可编程门阵列(FPGA)内部MicroBlaze嵌入式处理器为核心控制单元的二维脉冲压缩处理系统。根据FPGA内部不同的资源配置情况,提出2种脉冲压缩处理模块的实现结构,利用FPGA实现DDR SDRAM控制器,采用矩阵分块线性映射的方法实现高效的数据矩阵转置处理。通过模拟一个简单的合成孔径雷达成像处理过程,证明该系统的有效性。     

基于FPGA内嵌入式处理器的二维脉冲压缩

设计一个利用现场可编程门阵列(FPGA)内部MicroBlaze嵌入式处理器为核心控制单元的二维脉冲压缩处理系统。根据FPGA内部不同的资源配置情况,提出2种脉冲压缩处理模块的实现结构,利用FPGA实现DDR SDRAM控制器,采用矩阵分块线性映射的方法实现高效的数据矩阵转置处理。通过模拟一个简单的合成孔径雷达成像处理过程,证明该系统的有效性。     

基于WISHBONE的可兼容存储器控制器设计

随着近年来高速计算机的快速发展，人们对存储器频宽及性能的要求越来越高。作为第2代DDR存储器的DDR2 SDRAM具有高速、低功耗、高密度、高稳定性等特点，在未来的一二年里，它将逐步取代DDR SDRAM而成为内存的主流。尽管DDR2的地位正在不断上升，但DDR仍是当前流行的高速存储器。该文通过对这两种存储器的分析比较，基于WISHBONE总线，提出并实现了一种可兼容DDR与 DDR2存储器的控制器。     

视频解码芯片中DDR SDRAM控制器的设计

介绍了高速DDR SDRAM控制器没计以及在视频解码芯片系统中的应用。该设计将DDR控制单元和系统内部总线仲裁单元较好地整合成统一的控制器。根据DDR的工作原理和系统带宽要求，给出了DDR控制器关键部分在结构上和时序上的优化方案。同时还给出了FPGA原型验证的策略以及最后FPGA和ASIC的实现结果。     

基于FPGA的DDR SDRAM控制器的设计和实现

DDR SDRAM,因其拥有较之SDRAM为两倍的数据读、写速率,已经成为存储器的主流,并得到了广泛的应用,尤其在高速、高精度、高存储深度的数据采集系统中。本文在分析了DDR SDRAM工作原理的基础上,预先在FPGA上利用Verilog硬件描述语言设计实现了DDR SDRAM的读、写以及刷新,给出了DDR SDRAM控制器的状态转换图及结构框图,为进一步与微控制器或数字信号处理器的连接创造条件。目前该控制器已经研制完毕,进一步还可以集成到数据采集系统中。     

DDR SDRAM控制器的设计与实现

DDR SDRAM存储器已经得到广泛的应用。本文详细分析了DDR SDRAM控制器的结构和关键技术，并介绍了基于Altera FPGA的DDR SDRAM控制器实现。我们在深入分析DDR存储控制器工作原理及其内部结构后，直接使用Altera公司提供的IP核，在QuartusⅡ5．0开发环境中调用MegaCore（Altera公司的IPcore），根据具体应用需求进行了DDR SDRAM控制器的设计并加以实现。     

高速采样存储中DDR2 SDRANJ控制器的设计分析

通过比较,说明了二代双数据速率动态随机存储器（DDR2 SDRAM）的优势与特点。结合高速采样存储卡,介绍了板卡和存储控制器的硬件设计方案,重点阐述了关键技术和设计实现方法。对照时序仿真结果介绍了存储控制器的控制过程。最后总结了控制器模块达到的性能。     

基于FPGA的大容量数据高速采集系统的设计

介绍了一种基于DDR2 SDRAM与USB 2.0接口的大容量数据高速采集系统,该系统以FPGA为控制核心;利用FPGA的内部模块化的编程、DDR2 SDRAM的大容量存储以及USB 2.0接口的高速传输能力实现了数据的高速采集、大容量存储和传输;该系统支持热插拨和即插即用,使用方便;实验结果表明该系统可以实时高速的进行数据采集、存储和传输,最高传输速率可达20 MByte/s;在信号的高速采集领域有着很高的应用价值。     

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.     

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.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

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     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

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     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

正~~     

Information for Authors

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