理解Application对象与Session对象

我们知道,HTTP协议是无状态协议,Web服务器把每一个来自浏览器的请求视为一个独立的请求,Web服务器不保留以前请求的任何信息。所以当用户从应用程序中的一页转到另一页时,要维护整个访问或会话期间的用户信息便成为了一个难题。 Active Server Pages中Application对象和Session对象的引入一定程度上解决了HTTP协议无状态的缺陷,同时也成为了ASP区别于传统CGI的显著特征之一。Application对象用于在同一应用程序的所有用户会话中共享信息,一个用户改变了Application对象中变量的值,会影响所有用户对该变量的引用;而Session对象则用于在一个用户会话中共享信息,一个用户改变了Session对象中变量的值,不会影响其它用户对该     

ＨＴＴＰ协议在ASP编程中的应用

介绍了有关ASP编程知识和HTTP协议的基本内容,重点介绍ASP的内置对象Request,Response和Session的原理及HTTP协议在ASP编程中的应用,对于实际开发有很大的实用价值。     

基于Struts构架的Web认证

提出了利用Struts构架,设计和实现可重用的Web服务器认证算法,指出了纯Cookies认证算法的不足,论述了SSL安全协议和其在Web上的应用。利用J2EE的servlet重定向机制,实现HTTP和HTTPS无缝的混合使用。使用JSP的用户定制标签和servlet功能,设计了安全、可重用、易扩展的算法。并在Struts和Tomcat Web服务器环境下实现了算法。     

基于J2EE的新闻发布系统的分析与设计

本文针对J2EE技术进行深入研究,对Struts框架进行深入剖析,研究Struts框架的内部结构、运作流程,以及对MVC设计模式的分析研究和对MYSQL数据库进行深入了解,并提出了一个以J2EE为平台,使用Struts框架,引入MVC设计模式的基于J2EE的新闻发布系统。本系统提高了用户获取新闻信息的及时性,使用户能更...     

基于Struts与JSF的J2EE集成开发模式的应用研究

Struts框架经过数年的发展，已经成为程序员开发J2EE Web应用程序的一种事实上的标准。而JSF作为Web应用程序框架的新贵，其灵活的开发机制和强大的协议无关的用户界面组件呈现方法，正受到越来越多程序员的青睐。通过对这两种技术的分析比较，归纳出利用Struts—Fares在J2EE框架中整合Struts和JSF的方法．并通过实例详细阐述了基于Struts和JSF的Web框架开发流程。     

基于Struts与JSF的J2EE集成开发模式的应用研究

Struts框架经过数年的发展,已经成为程序员开发J2EE Web应用程序的一种事实上的标准。而JSF作为Web应用程序框架的新贵,其灵活的开发机制和强大的协议无关的用户界面组件呈现方法,正受到越来越多程序员的青睐。通过对这两种技术的分析比较,归纳出利用Struts-Faces在J2EE框架中整合Struts和JSF的方法,并通过实例详细阐述了基于Struts和JSF的Web框架开发流程。     

Struts与EJB结合的Web开发模式探讨

文章首先介绍了Struts的框架组成和设计原理,以及EJB中Session Bean及EntityBean的概念和设计方法;然后通过实例,对Struts与EJB结合的Web开发进行分析探讨,提出了Action(Struts)-Session Bean-Entity Bean的Web开发模式。     

Struts框架的分析及其改进

为了将Web应用中的业务逻辑和表现形式分离,尤其是降低在JSP文件中的Java代码,人们想了很多方法,其中应用Struts框架是较流行的方法。分析了Struts框架的缺陷,提出了Struts框架的改进方案,它大量采用XML、Xpath、XSL等技术和Struts框架,而不再使用JSP,同时将Struts中的FormBean、Session等需要显示的内容映射成XML内容,在XSL（表现层）中通过XSLT、Xpath技术访问,从而保证了XSL（表现层）中不再需要任何Java代码,真正实现了MVC的承诺。改进的Struts框架在智能大厦办公自动化系统中的成功实施说明了此方案是可行的。     

医院电子病历系统的设计与实现

为改善人工统计病历的管理效率,设计基于Struts框架协议和无线射频标签识别的医院电子病历智慧化信息管理系统。采用物联网组网融合和无线射频组网技术,构建智慧化网络分布模型并对电子病历进行信息化标记。通过Struts框架协议连接网络层和应用层,设计底层数据库结构设计,通过人机交互接口控制设计用户交互操作模块,在Struts框架协议下实现系统的软件开发设计。测试得知,设计的医院电子病历系统信息整合度较高,提升了电子病历的收发控制能力。     

引入Ajax的Struts验证框架的设计与实现

为了构建更加动态,响应更加快速的Web应用程序,在深入研究Ajax技术的基础上,将其引入到Struts的验证框架中,用来对应用程序中的表单数据进行验证,并给出一个简单的实例。结合了Ajax技术的Struts验证框架,增强了Struts验证框架的功能,同时可以减轻服务器端压力,提高系统响应速度,减少用户等待时间。     

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).