浮点反正切函数的FPGA实现

设计了一种基于CORDIC算法计算浮点反正切函数的的硬件结构,并在Altera公司的FPGA芯片上进行了验证,最后在Nios II处理器系统中以用户自定义指令的形式实现,通过C语言程序验证了浮点反正切模块的正确性。     

基于FPGA的反正切函数的优化算法

主要描述了一种基于FPGA利用Verilog HDL实现的反正切函数计算的优化算法.反正切函数的计算在相位检测,偏振光检测等检测系统有重要的应用.讨论了泰勒展开式法和直接LUT查找表法缺点,提出一种新的优化LUT查找表算法.该算法能够被综合器综合实现,可以直接集成在FPGA应用系统、SOC系统或SOPC系统上,并且经软件仿真和硬件验证,达到了设计要求.     

三种轴角数字转换电路的分析与比较

介绍了三种分别基于单片机、轴角数字转换模块和光电编码器的轴角数字转换电路的原理,并对其性能进行了分析和比较。     

颜色空间转换在视频采集显示系统中的应用

详细介绍了一种视频采集显示系统,针对视频处理常用的视频解码芯片输出的YCbCr4∶2∶2的视频格式,用FPGA实现串并转换,颜色空间转换,去隔行处理等算法,最后通过视频编码器ADV7123实现了RGB图像的输出.     

高精度微弱电容检测系统的设计

针对微弱电容信号的检测问题,提出了一种基于FPGA和数字解调的高精度微弱电容检测系统;通过硬件设计和软件设计,实现了由电源电路、C/V转换电路、FPGA电路、A/D转换电路等组成的高精度电容检测系统;阐述了利用载波调制进行微弱电容检测的原理和系统硬件电路的实现方案,并给出了基于cordic算法的载波生成、数字解调和AD采样控制在FPGA中的具体实现;实际运行表明,该检测系统的电容检测分辨率可达到5fF,具有精度高及抗干扰能力强等优点.     

基于FPGA的高清视频采集与显示系统设计

介绍了一种基于FPGA的视频采集与显示系统的设计.系统以FPGA为核心,配合高分辨率CCD图像传感器、ADC模数转换、视频编码器等,实现了高清视频实时采集与显示.详细阐述了色彩插值与色彩空间转换算法和BURST传输的FPGA硬件实现.测试表明,该系统运行良好,能够满足高清视频实时监控要求.     

一种基于FPGA的高速自整角机数字解算方法

自整角机是广泛应用于轴角测量系统中一种非常重要的测量元件,现场可编程逻辑门阵列(FP-GA)技术近几年的发展使得利用硬件描述语言实现信号的快速实时处理成为可能。设计采用Spartan-3系列的XC3S400芯片,根据自整角机输出信号的特点和角度测量原理,利用Verilog HDL语言编程完成控制逻辑和自整角机角信息的解算。应用坐标旋转数字计算机(CORDIC)算法在FPGA中实现了反正切函数的计算,并引入改进的CORD IC算法以提高运算速度,节省硬件资源。经过测试,达到0.01°的轴角解算精度,角度解算区间达到[-360°,360°],并且,在不同的角度偏移量和不同的轴初始位置情况下都能获得满意的结果。     

基于ARM的直流电机位置伺服系统设计

针对图像跟踪中对转台响应快、定位精度高的要求,设计了以ARM和轴角转换芯片组成的位置伺服控制系统。系统使用轴角转换芯片采集旋转变压器反馈的位置信息,通过IR2130驱动MOSFET功率管构成的H桥电机驱动电路,采用带有速度前馈加速度前馈的PID调节算法实现了直流电机位置伺服控制。试验结果表明该控制系统能够满足图像跟踪中对转台快速性和准确性的要求。     

用CMOS器件设计循环式线性编码器

循环式线性编码器是一种采用串行反馈A/D转换方式的信源编码器,速度较慢,但电路简单,本文针对边远地区、分散用户及移动通信等的需要,提出了用CMOS器件实现的具体方案,该方案便于实现单片集成。     

基于PCI总线的通用旋转变压器解算系统设计

针对轴角参量的闭环控制和检测的局限性,设计了一种基于PCI总线的通用旋转变压器解算系统;通过DDS模块和功率放大电路产生激磁信号,在FPGA的控制下,解算芯片完成轴角参量的解算;采用FIFO机制进行数据缓存,采样时标达到0.1ms;系统具有激磁信号频率0Hz到10kHz可变、速比1∶8到1∶64可调的特点,是一种精度高、通用性好的轴角检测解决方案。     

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)

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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