激光雷达数据无损压缩的FPGA实现

为提高测距激光雷达海量回波数据的存储和传输效率,在以FPGA为核心的激光雷达数据采集系统中实现了对回波数据的Lempel-Ziv-Welch(LZW算法)基于字典的无损压缩;通过对字典管理进行简化,利用FPGA芯片内的RAM来存储字典,采用逻辑电路来处理压缩算法,算法的主体为Verilog语言描述的有限状态机;经过仿真验证与综合,结果表明该算法的FPGA实现能获得30%左右的压缩比,压缩速度满足系统要求.     

远程故障诊断系统通信数据压缩技术研究与验证

根据远程故障诊断的测试数据的网络传输特点,在详细分析和比较了多种数据压缩算法的基础上,针对LZW算法字典列表长度有限、查找时间长等问题,利用加入了动态延伸列表长度、根据压缩比例调整已有的字典内容和哈希函数查找等方法,对LZW算法提出了改进措施;同时,引入MPEG帧间压缩的思想,设计了一种新的"周期性差值压缩方法",将改进的LZW数据压缩算法与"周期性差值压缩方法"相结合,构成了更有效的级联数据压缩方法,有效地提高了数据压缩比率和效率,并且该算法的处理速度能够满足远程故障诊断系统对通信的要求。     

一种遥测数据实时采集压缩系统的实现

设计了一种对遥测大容量速变数据的实时压缩采集方案,通过采用改善无损压缩算法的压缩比、压缩和解压速度以及算法复杂度等多个数据压缩性能,提出了综合性能较好的LZW编码作为数据压缩的核心算法并通过软件仿真确认其效果和压缩算法的执行速度;利用主控芯片FPGA完成对压缩数据的高精度采集,对研制的数据采集压缩系统进行整体测试,测试结果表明,该系统完成了6路速变参数的实时采集与压缩,压缩比达到1.8∶1以上,各项指标满足了设计要求.     

高速数据压缩与缓存的FPGA实现

本文设计了一种以FPGA为数据压缩和数据缓存单元的高速数据采集系统,其主要特点是对高速采集的数据进行实时压缩,再将压缩后的数据进行缓冲存储.该设计利用数据比较模块实时地将一个压缩比数组中的最大值保存起来,再将该最大值缓冲存储,从而满足采集系统的需要.文中分别设计了基于双口RAM和FIFO实现的两种缓冲方法,并对仿真结果进行了对比分析,该系统工作频率可迭90MHZ.     

离散余弦变换在心电信号压缩中的应用研究

目前心电（ECG）信号压缩是生物医学信号压缩的一个热门研究领域.临床诊断过程中,心电信号的存储与传输是一个有待解决的问题,由于采集到的原始信号数据量巨大,为了便于对大量的心电数据进行存储、分析和传输,对于这些数据的压缩处理是十分必要的.通过对心电数据压缩方法的概述与讨论,在研究国内外有关心电信号数据压缩算法及其研究状况的基础上,采用了离散余弦变换（DCT）算法对心电信号进行压缩,取得了较高的压缩比和保真度,具有一定的应用价值.     

分布式监测系统缓变信号无损压缩方法研究

分布式监测系统长时间的连续监测会产生大量的状态参数,为了数据实时连续传输及节省以数据流量计费的数据传输成本,在分析分布式监测系统传输模型基础上,对无损压缩方法中的霍夫曼编码和LZW算法进行了研究;针对缓变信号相似程度高的特点,提出了基于动态规划的霍夫曼编码和LZW数据压缩算法,使用上述方法,对发动机状态监测数据进行压缩,通过比较,基于动态规划的霍夫曼编码方法压缩率最高,对于水温、油温、油压性能参数的压缩率均在60%以上,该方法成功应用于大型复杂装备分布式监测系统中,有效减少了信号冗余度,提高了数据传输效率。     

一种高效的通用数据压缩算法

本文在著名的LZW数据压缩算法基础上,提出一种新的数据压缩算法。新算法以对已压缩过的数据进行历史分析为手段,采用三个编码器对源数据序列分类编码。该算法适用压缩各种类型的数据,完全兼容LZW算法,并在平均压缩率方面较后者有较大的提高。     

数据压缩在次声监测中的应用

随着次声监测要求的不断提高,次声监测数据量急剧增加,这使数据传输、存储、处理的压力也越来越大。为了解决该问题,结合次声监测数据体存在信息冗余和互相关的特性,采用有能量集中效应的改进型离散余弦变换(MDCT)、改善信噪比的非线性压缩与扩张量化和高编码速率的自适应Huffman统计编码技术,对次声数据体进行压缩处理。该技术是一种有损压缩技术,根据数据的信噪比、松散度、复杂度等数据特征,统筹数据压缩和损失程度,合理选择压缩比,实现对次声监测数据体的低失真压缩。     

基于DSP的存储测试系统设计

针对武器动态测试中的数据参数进行研究,设计了基于TMS320F2812 DSP的数据采集与处理系统.在深入了解信号特征的基础上,结合当今数据压缩发展的前沿技术,设计、改进得到一种可应用于实际情况、能够满足实际需求的LZW和游程混合压缩算法.对数据压缩效果进行了测试,试验证明采用该算法能实时、高效地对AD采集到的数据进行压缩.     

一种基于SDT算法的新的过程数据压缩算法

针对流程工业实测过程数据压缩存储问题,在深入分析旋转门（SDT,Swing Door Trending）算法的基础上,提出了一种基于SDT算法新的过程数据压缩算法（NSDT,New Swing Door Trending）。NSDT算法采用曲线对过程数据进行拟和以实现数据压缩,与SDT算法相比能取得更好的压缩效果。根据理论分析和实验数据结果分析,证明了NSDT算法确实可以在不增加压缩误差的前提下,有效地提高压缩比。     

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