ASP.NET中Dropdownlist控件的使用技巧与应用实例

作为今后Web应用开发的主流技术之一,ASP.NET为我们提供了为数众多的具有强大功能的内置控件,利用这些控件可以很方便的实现我们需要的功能。但是在不同的场合下人们对功能的需求是不同的,因此在熟悉ASP.NET各控件功能的同时,对控件使用技巧的掌握也是必不可少的。本文通过一个完整的实例详细介绍了DropDownList控件的联动技巧,并对联动过程中出现的问题给出相应的解决方法。     

ASP.NET中多个DropDownList控件的动态数据绑定

作为今后WEB应用开发的主流技术之一,ASP．NET为我们提供了为数众多的具有强大功能的内置控件,利用这些控件可以很方便的实现我们需要的功能。但是在不同的场合下人们对功能的需求是不同的,因此在熟悉ASP．NET各控件功能的同时．对控件使用技巧的掌握也是必不可少的。该文通过一个完整的实例详细介绍了多个DROPDOWNLIST控件的数据源绑定技巧。     

基于ASP.NET的Web GIS数据库访问的实现

ASP．NET是微软推出的新一代动态网页技术，在ASP．NET中，对数据库的访问是通过ADO．NET来实现的，ADO．NET对象模型中的DataSet对象提供了一系列访问数据库的接口，因此利用ASP.NET提供的ADO．NET可方便地实现对GIS属性数据的访问；同时可利用ASP．NET提供的自定义控件的功能，通过定义一系列具有空间数据操作功能的地图控件、远程处理（．NET Remoting）技术与创建的地图服务（Map Service），实现对GIS空间数据的访问和显示。     

基于ASP.NET的Web GIS数据库访问的实现

ASP.NET是微软推出的新一代动态网页技术,在ASP.NET中,对数据库的访问是通过ADO.NET来实现的,ADO.NET对象模型中的DataSet对象提供了一系列访问数据库的接口,因此利用ASP.NET提供的ADO.NET可方便地实现对GIS属性数据的访问;同时可利用ASP.NET提供的自定义控件的功能,通过定义一系列具有空间数据操作功能的地图控件、远程处理(.NET Remoting)技术与创建的地图服务(Map Service),实现对GIS空间数据的访问和显示。     

基于ASP.NET Ajax下拉框联动的实现

本文介绍了使用ASP．NET Ajax技术提供的CaseadingDropDown控件实现无刷新的下拉框联动。     

基于GridView控件仿Excel格式显示数据的网页制作

通过一个实用的网页实例,深入探讨了ASP.NET的GridView控件模仿Excel格式显示数据的网页制作思路与实现过程,介绍了GridView控件在冻结窗格、合并单元格、自动编号和自定义分页控件等功能的编程技巧。     

ASP.NET2.0开发中的认证和授权

几乎每个Web应用都会涉及针对不同的用户进行权限分配的工作,用户登录后根据不同的权限访问系统不同的资源和实现不同的功能。在ASP.NET2.0之前,我们需要自己开发这样的功能,但是在ASP.NET2.0中,随着成员（Mem-bership）服务和相关控件的推出,极大地减轻了相关工作的工作量。     

ASP.NET控件和数据缓存机制的综合应用

网页具有不保留状态的特点,使得站点服务器的访问效率、资源的有效利用特别重要.为了提高用户的访问效率和资源的利用率,我们需要其相关的ASP.NET的高级技术,典型的就是使用用户控件、自定义控件、ASP.NET中的代码重用、ASP.NET中的数据缓存机制以及ASP.NET中的页面缓存机制。下面我们将分别介绍如何创建几种控件和数据缓存机制,以及在ASP.NET环境下他们的具体使用及其相互的区别。     

基于GridView控件的业务单据设计

GridView是ASP.NET中的数据绑定控件,常用来在网页中显示多行数据,并可对数据行进行修改和删除操作,但没有添加数据行的功能。在软件设计中可通过一些技巧来拓展GridView的功能,通过业务管理系统的单据处理过程,介绍GridView控件的一些实用技巧。     

ASP.NET实现在数据库中二进制格式存取图片

以二进制格式在数据库中存储图片具有安全性高、易于管理等优势,不同的数据库管理系统和不同的开发技术在实现方法上有所不同。本文研究使用ASP.NET2.0提供的相关控件和流技术实现在Access数据库中以二进制格式存取并显示图片。以常见的会员管理系统中的注册与编辑功能为例来,阐述了用ASP.NET在数据库中以二进制格式存取并显示图片的技术特点、技巧和方法。     

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).