基于SVG的Web远程实时监测客户端研究*

针对现有基于Web的监测系统客户端技术在实时性方面的不足,利用可缩放矢量图形(SVG)和Ajax技术设计了一种新的基于Web的远程实时监测客户端系统。该系统利用SVG技术实现图表绘制,利用Ajax进行数据通信和传输,完成了一套完整的基于Web的图表组件,并在振动监测系统中得到了实现,具有良好的实时性。     

DCS监控画面的Web发布实现

研究了在DCS监控画面图中应用SVG和Ajax技术来实现Web发布的可能.利用SVG对图元对象的支持以及基于XML标准的事实,将DCS实时监控画面图从本地系统移植到Web应用上.利用SVG对图形交互的支持,结合Ajax技术实现了监控画面实时数据的传输和人机交互.实例证明,上述方案具有网络流量小、易维护、可重用等优点.     

基于SVG的管道系统技术研究

针对B/S应用中的Web服务器与浏览器间频繁操作导致Web应用执行速度慢的问题,在SVG的基础上利用Ajax和Web服务等技术,实现基于SVG的管道系统.运用Ajax实现Web无刷新页面更新数据,在客户端利用SVG提供的DOM编程接口和JavaScript脚本语言对SVO进行开发,实现其交互功能.通过该系统可以查看管道的布局,管道实时信息,监测管道实时流量变化.     

SVG技术在煤矿监控系统中的应用研究

为了以图形图像形式高效发布煤矿实时数据,提出将SVG技术应用到煤矿监控系统中,介绍了基于SVG技术的实时数据发布方案。该方案采用Ajax技术获取数据库服务器中的实时数据,并利用SVG技术构建直观、实时的远程监控矢量图形页面,实现了实时数据的加载及显示。     

基于XML Web Service和Ajax的Web实时分布式系统的架构及应用

如果WEB系统的用户数比较多、数据计算比较复杂、数据库访问量比较大,人机交互量比较大,就会使传统的Web系统无法满足用户的实时性要求.通过XML Web Service可以均衡Web服务器的负载,创建分布式Web系统;通过Ajax可以创建无需等待、无需刷新的Web交互模式.本文提出了基于XML Web Service和Ajax的Web实时分布式系统的架构方案,并进行了具体应用.     

基于XML Web Service和Ajax的Web实时分布式系统的架构及应用

如果WEB系统的用户数比较多、数据计算比较复杂、数据库访问量比较大,人机交互量比较大,就会使传统的Web系统无法满足用户的实时性要求.通过XML Web Service可以均衡Web服务器的负载,创建分布式Web系统;通过Ajax可以创建无需等待、无需刷新的Web交互模式.本文提出了基于XML Web Service和Ajax的Web实时分布式系统的架构方案,并进行了具体应用.     

基于Ajax的Observer模式客户端研究

针对现有的工业大型设备远程监测系统中Web客户端存在的实时性差和代码复用率低的问题,提出基于Ajax的Observer模式Web客户端构建方案。利用Ajax技术解决监测系统中客户端图形显示的实时性问题,并与Observer设计模式相结合,提高了代码复用率,降低了模块之间的耦合性。通过演示系统程序完整地验证了该方法的可行性。     

基于WebServices和Ajax的实时传输系统架构

传统的Web系统无法满足用户的实时性要求,本文提出了基于Web Services和Ajax的Web数据实时传输系统,并进行了具体应用。传统的Web应用采用同步交互的方式,当负载较大而带宽较小时响应时间就会变长,甚至会出现超时现象。Web服务可以均衡Web服务器的负载,创建开放分布式系统;Ajax可以优化浏览器和服务器之间的数据传输,可以减少不必要的数据往返,减少带宽应用,减轻服务器的负担。结合二者可以有效地创建实时分布式Web系统,本文给出了二者结合进行数据传输的架构方案,并通过实例展示了其实现方法。     

基于Ajax和SVG的Web远程实时监控系统

以ASP.NET为平台,使用Ajax和SVG实时显示技术完成了基于Web的B/S模式远程监控,实现了跨操作平台的网站式远程实时监控系统,将实时监测与控制系统构筑于Internet之上,通过Internet实现对现场设备的实时远程监控、设备故障诊断与调试。设计的前端设备远程监控器可实时监控现场设备的工况,方便组网实现多监控点的实时监控,易于扩展。应用结果表明,该系统有良好的实时性、可靠性、交互性和扩展性。     

J2EE平台下基于RFID的单件生产监控

为了掌握生产现场的实时状态,采用J2EE平台对基于RFID的单件生产实验系统的远程监控系统进行了设计。该系统应用内存映射文件技术来共享由RFID设备采集的生产状态数据,利用Ajax技术的异步通信机制以及SVG技术的动态显示,可以准确地把单件生产实验系统的实时变化反映在监控界面上,生产管理人员还可通过历史数据库可以方便追踪产品的加工过程。运行结果表明,该系统具有良好的实时性,且运行稳定,能够完成对整个生产过程的远程实时监控。     

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).