基于XML信息交换的多Agent电子商务系统

随着Internet的出现和发展,电子商务技术也有了长足的进步,Agent概念的出现及其技术的进步,使它成为自动完成电子商务活动代理的理想选择。首先,文章基于多Agent思想构造了一个电子商务系统框架;其次,对此系统中Agent之间的通信协议要求进行了规范;通过分析,选择了XML作为Agent之间通信的消息格式;最后,在上述平台上集中研究了如何将关系型数据转换成XML数据的方法,并对此进行了实现。     

CORBA技术在现场设备通信中的应用*

首先简要介绍CORBA体系结构,阐述了利用CORBA的代理机制,通过代理屏蔽不同通信协议差异,以实现设备之间通信的集成策略.该机制能够方便地实现不同协议设备之间的通信集成,而且便于系统扩展,并兼容多种操作系统平台.最后结合具体实例给出现场设备的集成方案.     

基于XML的综合网管对象数据交换

基于XML的Wed Services技术非常适合解决综合网管通信系统不同子系统之间互联、互通、互操作并建立完整的业务管理信息模型。文章介绍了在综合网管系统中基于XML中间件的数据交换(XMI)的实现。     

基于RDF/XML的异构数据交换模型的设计与研究

为了解决各个相互孤立的应用系统之间由于缺乏信息共享和互通互联的通道和平台,协同应用困难,共享程序低的问题,提出了基于RDF/XML的异构数据交换模型。该模型充分考虑了各个应用系统的特点,通过基于RDF/XML的异构数据交换模型,达到不同系统间的数据传输,实现跨部门、跨系统、跨异构数据库的数据交换。     

基于RDF/XML的异构数据交换模型的设计与研究

为了解决各个相互孤立的应用系统之间由于缺乏信息共享和互通互联的通道和平台,协同应用困难,共享程序低的问题,提出了基于RDF/XML的异构数据交换模型.该模型充分考虑了各个应用系统的特点,通过基于RDF/XML的异构数据交换模型,达到不同系统间的数据传输,实现跨部门、跨系统、跨异构数据库的数据交换.     

基于XMPP的即时通信网关应用研究

XMPP最终要实现不同即时通信系统间的互通。主要介绍对XMPP与其他IM互连互通的网关原理及其应用进行的研究讨论,并以jabber系统与MSN Messenger进行互发信息作为实例进行详细阐述。     

面向语义Web的约束规则系统

随着语义Web的广泛使用,信息智能搜索、智能信息代理、智能交易代理等等智能化电子商务应用将成为现实。与此同时,规则在电子商务中的应用也取得了长足的进展。文中介绍的面向语义Web的约束规则系统结合两者的优势通过使用XML描述约束规则系统的语法、扩充在处理异构数据源方面的谓词和查询表示、引入并行约束程序设计的推理技术、规则选择机制的编译实现完成了规则系统在电子商务异构数据处理及商务决策方面的应用。     

智能WEB信息提取系统的研究和设计

XML业已成为WEB数据发布与交换的标准,包装器技术为数据挖掘提供了重要实现步骤,智能代理技术以其智能、代理特性在控制协调挖掘上起着重要作用.本文将这三项标准和技术进行有机结合,应用于WEB数据挖掘上,借助J2EE三层体系结构思想,给出了智能WEB信息提取实现方案,并简要阐述了该系统处理用户挖掘请求的流程,体现了该系统较强的智能理解和概括能力.     

智能WEB信息提取系统的研究和设计

XML业已成为WEB数据发布与交换的标准,包装器技术为数据挖掘提供了重要实现步骤,智能代理技术以其智能、代理特性在控制协调挖掘上起着重要作用。本文将这三项标准和技术进行有机结合,应用于WEB数据挖掘上,借助J2EE三层体系结构思想,给出了智能WEB信息提取实现方案,并简要阐述了该系统处理用户挖掘请求的流程,体现了该系统较强的智能理解和概括能力。     

面向语义Web的约束规则系统

随着语义Web的广泛使用,信息智能搜索、智能信息代理、智能交易代理等等智能化电子商务应用将成为现实.与此同时,规则在电子商务中的应用也取得了长足的进展.文中介绍的面向语义Web的约束规则系统结合两者的优势通过使用XML描述约束规则系统的语法、扩充在处理异构数据源方面的谓词和查询表示、引入并行约束程序设计的推理技术、规则选择机制的编译实现完成了规则系统在电子商务异构数据处理及商务决策方面的应用.     

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).