利用缓存优化基于ASP.NET的Web GIS性能

随着WebGIS的快速发展和广泛应用,对WebGIS的性能提出了更高的要求。ASP.NET是微软推出的新一代动态网页技术,它提供了强大的Web应用开发功能,依托ActiveX技术,开发基于ASP.NET的WebGIS是当前实现WebGIS的较佳方案。基于ASP.NET的WebGIS的优点在于其灵活性和动态特性,但是在获得这种灵活性和动态特性的同时却导致WebGIS性能降低。加之ASP.NET属于ActiveX技术中的Server端技术,对于ASP.NET而言,所有的一切都是在服务器端运行的,这就更增加了服务器的负载,同时,虽然ASP.NET页面是编译型的,但页面中的许多操作将占用大量的服务器资源。因此有必要用运ASP.NET的缓存技术,降低WebGIS服务器的负载,使得设计和实现的WebGIS性能更优,效率更高。     

TreeView树结构动态绑定在ASP.NET 2.0中的应用

TreeView作为ASP.NET 2.0的服务器组件使得网站页面导航功能更为强大,但常规的静态绑定树结构,使得其在使用上受到一定限制.利用数据库动态查询,动态添加绑定树结构,无疑为TreeView的使用另辟蹊径.动态绑定多层次TreeView树结构,使得TreeView的导航功能更加灵活方便.     

基于ASP.NET 技术的Web人事管理信息系统的设计与实现

微软推出的基于ASP.NET 的Web应用或动态网站开发技术,使得Web应用的开发更加简单和快捷。论述了一个基于ASP.NET,ADO.NET和SQL Server 2000相结合的Web人事管理系统的设计原理、总体结构及功能实现,已有效解决了人事管理信息系统的Web动态发布等问题,并设计了DataGrid控件的数据添加方法来增加数据处理的灵活性。     

ASP.NET运行时模型的源码解析

ASP.NET是微软公司推出的基于DotNet平台的网络开发技术,对B/S模式应用的开发提供了强大的支持,该文从源代码级别进入ASP.NET底层,分析ASP.NET运行时模型,揭开ASP.NET应用程序运行的幕后细节。     

5ASP．NET新特性的初步研究

本文主要介绍5ASP．NET的各种新特性。5ASP．NET提供对编译语言的访问，提高了其性能和可扩展性。Web窗体使得开发更直观，面向对象机制使得重利用更便利。此外，服务器控制及在数据绑定上的提高也是5ASP．NET的新颖之处。5ASP．NET为使用库及允许在网页上定制商业功能的Microsoft.NET框架提供了更新的开发机会。     

ASP.NET协同SQL SERVER技术在专题学习网站应用研究

基于ASP.NET＋SQL SERVER技术的Web应用或动态网站开发技术。使得Web应用的开发更加简单快捷。本文论述了一个基于ASP．NET、ADO，NET和SQL SER．VER2000技术有机结合的专题学习网站设计原理、总体架构及其功能实现，该网站为使用者交流提供一个全新的互动平台，交互功能强，有较好的应用前景。     

基于ASP.NET的企业Web服务的应用与实现

阐述Web服务实现的原理,通过实例描述在企业的实际应用,结合ASP.NET和MS SQLServer,实现Web服务的创建、测试和调用的全过程,展示了ASP.NET创建、部署和使用Web服务的强大功能.     

基于ASP.NET的在线教育系统设计与实现

在线教育系统以学院或者教学系为教学单位进行设置,采用Web流行的客户机/服务器模式更加适应学校的发展。ASP.NET技术作为中间件,以SQL Server 2000作为后台数据库,并对ASP.NET与CGI、PHPJ、SP进行比较,阐述了在线教育系统的系统结构,对各个功能模块、试卷生成算法及所采用的关键技术做了详细描述,实现了在线教育系统的一般功能。基于ASP.NET的程序设计使得该系统更易维护、更安全、更稳定。     

asp.net三层架构体系的分析与应用

在计算机软件系统中,应用ASP.NET组件进行开发的计算机软件系统中,一般情况下这个计算机软件系统的一个重要核心工作就是要实现计算机软件系统的数据访问功能。ASP.NET三层架构体系就是为了实现ASP.NET组件开发的计算机系统软件的结构性以及可重要性而应用的一种计算机系统软件开发模式。本文主要从ASP.NET三层架构体系的设计以及ASP.NET三层架构体系在实际中的应用两方面,对于ASP.NET三层架构体系及其应用进行分析论述。     

基于ASP．NET的主题在网站设计中用户登录界面的应用

主题是ASP．NET的一项强大的应用功能,通过利用主题功能．可以减少需要添加到各个ASP．NET页面的内容量,一次定义控件的外观,将该外观应用于整个Web应用程序。在实例中重点介绍主题在网站设计中用户登录界面的具体应用．使用主题功能可以轻松创建具有一致的并可维护的外观设计的网站。     

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).