基于GPRS和嵌入式Linux的远程图像监控系统

阐述了一种基于GPRs和嵌入式Linux的远程图像监控系统设计和实现方法。该系统主要由嵌入式视频采集终端和监控中心服务器组成。其中,嵌入式视频采集终端主要由摄像头视频采集模块、ARM模块、SIM900模块组成,监控中心服务器可实时监控远程终端的图像。系统软件采用嵌入式Linux,可编程实现图像数据采集、压缩和GPRs模块的网络连接与传输。     

基于ARM/WiFi/QT的无线视频监控系统的开发

利用ARM和QT开发了一款基于WiFi网络的无线视频监控系统.系统由远程视频采集端、WiFi网络和监控中心三部分构成.远程视频采集端采用 PXA270 ARM10微处理器为核心的硬件平台,并在其上建立 Linux操作系统,完成视频的采集、H.264编码压缩和传送.监控中心使用QT利用多线程技术开发了客户应用软件,实现监控视频的解码和显示. WiFi网络实瑞视频采集端和监控中心间的视频传输.使用效果表明,该系统能稳定实时地显示一路或多路视频监控图像,很好地达到了设计的要求,在各领域具有广泛的应用前景.     

基于视频网络服务多通道数据采集系统的研究与设计

现有水文遥测终端无法实现包括视频信号在内的多通道数据采集,传统的视频网络监控也不能很好满足水利水文行业的遥测需求,通过利用信息融合技术,提出一种基于嵌入式ARM系统的水利水文多通道数据采集控制方案。该多通道系统终端软件部分采用嵌入式Linux系统编程,硬件部分控制多通道信息的采集。实验结果表明,该系统终端采集通道具有很强可扩展性,并且实现基于嵌入式终端的视频图像、图片采集,具有很好的技术先进性和良好的应用前景。     

物联网技术在自动化立体仓库的应用研究

针对目前自动化立体仓库监控技术存在的缺点,提出了一种基于物联网RFID电子标签无线通信技术的自动化立体仓库监控管理系统.系统以物联网技术为核心,通过电子标签实现系统数据的实时采集;同时,利用GPRS无线模块把采集到的数据发送给监控中心,监控中心接收并处理数据,最后将结果显示给用户或发出监控命令,实现系统管理智能化、网络化和信息化.该物联网技术在自动化立体仓库领域具有较好的应用前景.     

一个分布式数据采集系统的设计与研制

对现有的数据采集系统结构与性能进行研究后,设计了模块式数据采集盒和分布式数据采集系统结构.该系统利用网络技术,将采样、监控计算机和独立的数据采集盒连接起来,实现多现场、多通道实时数据的监控、采集与处理.给出了系统总体结构、数据采集盒原理与设计、系统软件功能设计和系统实现方案.采集频率达到每通道每秒1～30 次,可同时采样5 000通道、监控2 000通道,兼有模拟仿真与数据处理功能.     

基于Zynq-7000的宽幅视频处理系统设计与实现

针对安防监控与智慧交通领域无盲区视频摄录的需求,基于Zynq-7000平台优势进行宽幅视频处理软硬件系统的设计。通过研究基于嵌入式系统的多路视频实时拼接技术,设计并实现了以XC7Z020芯片为核心的视频处理板卡,在双核ARM Cotex-A9硬核处理器端服务程序协同调度下,基于片内FPGA硬件加速能力实现多通道视频实时采集与预处理、投影变换、图像融合,进而形成完整宽幅视频画面,通过远程客户端实现定制化的视频摄录功能。测试结果表明,该系统是兼具稳定的性能和灵活区域部署能力的便携式解决方案。     

基于WMN的无线视频监控系统的设计

结合无线Mesh网络(WMN)的技术特性和网络视频监控的新要求,提出了一种基于WMN的视频监控系统设计方案。监控终端通过摄像机和基于嵌入式Linux平台的视频服务器完成视频采集和压缩,利用WMN进行实时传输,监控中心在Mesh网络的覆盖范围内通过因特网进行视频数据接收,实现无线视频监控。实验测试结果表明,该系统播放流畅、实时性好,在无线视频监控中具有广泛的应用前景。     

几种移动无线视频传输技术的比较与选择（上）

基于无线传输方式实现的移动视频监控,是指在移动目标上加装前端视频采集装置,通过传输单元将视频信号传输至监控中心,实现对移动目标动态、实时地跟踪、监控、调度的目的。移动视频监控系统的优点,主要表现为组网极其灵活、扩展性好,可摆脱线缆束缚、实施周期短、综合成本低等。本文介绍GPRS、CDMA、COFDM几种移动无线视频传输技术的含义、原理、优缺点、性能比较与选择。     

基于WSN的水稻生长环境远程监测系统研究

基于WSN的水稻生长环境远程监测系统,以ARM9为核心,结合ZigBee技术和3G技术,实现水稻田间多参数的实时与远程监控。该系统将传感器节点采集到的数据通过ZigBee无线网络发送到网关节点,通过3G技术建立协调器网关节点与远程监控中心的无线连接,监控中心PC连接了3G网络和MySQL数据库。用户可通过远程PC实时监测、查询水稻生长环境信息,从而提高水稻生产自动化管理水平。     

嵌入式无线视频监控系统的设计与实现

在数字网络视频监控技术蓬勃发展的背景下,提出了一种基于Ad Hoc网络下的视频监控系统构建方案,并详细阐述了系统的总体结构、嵌入式操作系统、硬件的基本框架、传输协议、监控中心的软件结构、Socket的编程原理,以及系统的实现过程。在前端设备通过该嵌入式系统,监控中心设立服务器的方式,实现无线网络条件下的视频实时监控。系统的试运行结果表明,该系统设计新颖,技术先进,工作稳定,能够显著提高视频监控系统的实时性、实用性。很好实现了系统预定的目标要求。     

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。     

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。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

Enhancing a leaf radiative transfer model to estimate concentrations and in vivo specific absorption coefficients of total carotenoids and chlorophylls a and b from single-needle reflectance and transmittance

The relative concentrations of different pigments within a leaf have significant physiological and spectral consequences. Photosynthesis, light use efficiency, mass and energy exchange, and stress response are dependent on relationships among an ensemble of pigments. This ensemble also determines the visible characteristics of a leaf, which can be measured remotely and used to quantify leaf biochemistry and structure. But current remote sensing approaches are limited in their ability to resolve individual pigments. This paper focuses on the incorporation of three pigments—chlorophyll a, chlorophyll b, and total carotenoids—into the LIBERTY leaf radiative transfer model to better understand relationships between leaf biochemical, biophysical, and spectral properties.Pinus ponderosa and Pinus jeffreyi needles were collected from three sites in the California Sierra Nevada. Hemispheric single-leaf visible reflectance and transmittance and concentrations of chlorophylls a and b and total carotenoids of fresh needles were measured. These data were input to the enhanced LIBERTY model to estimate optical and biochemical properties of pine needles. The enhanced model successfully estimated reflectance (RMSE = 0.0255, BIAS = 0.00477, RMS%E = 16.7%), had variable success estimating transmittance (RMSE = 0.0442, BIAS = 0.0294, RMS%E = 181%), and generated very good estimates of carotenoid concentrations (RMSE = 2.48 µg/cm², BIAS = 0.143 µg/cm², RMS%E = 20.4%), good estimates of chlorophyll a concentrations (RMSE = 10.7 µg/cm², BIAS = − 0.992 µg/cm², RMS%E = 21.1%), and fair estimates of chlorophyll b concentrations (RMSE = 7.49 µg/cm², BIAS = − 2.12 µg/cm², RMS%E = 43.7%). Overall root mean squared errors of reflectance, transmittance, and pigment concentration estimates were lower for the three-pigment model than for the single-pigment model. The algorithm to estimate three in vivo specific absorption coefficients is robust, although estimated values are distorted by inconsistencies in model biophysics. The capacity to invert the model from single-leaf reflectance and transmittance was added to the model so it could be coupled with vegetation canopy models to estimate canopy biochemistry from remotely sensed data.     

Mr. Twinn’s bombes

This article discusses the history and design of the special versions of the bombe key-finding machines used by Britain’s Government Code & Cypher School (GC&CS) during World War II to attack the Enigma traffic of the Abwehr (the German military intelligence service). These special bombes were based on the design of their more numerous counterparts used against the traffic of the German armed services, but differed from them in important ways that highlight the adaptability of the British bombe design, and the power and flexibility of the diagonal board. Also discussed are the changes in the Abwehr indicating system that drove the development of these machines, the ingenious ways in which they were used, and some related developments involving the bombes used by the U.S. Navy’s cryptanalytic unit (OP-20-G).