基于Web Services的异构空间信息共享

异构集成技术正日益成为信息资源管理的一个热点技术。以地理信息共享的应用为背景,提出了基于Web Services的异构空间信息共享体系结构。通过引入Web Services技术架构,设计了一个异构空间信息共享系统。该系统可提供各信息源灵活、动态发布自身服务的功能,从而为快速构建异构集成系统提供了性能保证。     

基于Web信息搜索的空间信息门户

空间信息门户为用户提供一个统一的入口访问分散异构的空间信息资源，是国家空间信息基础设施的重要组成部分。传统的空间信息门户大多采用OGC在空间信息门户参考体系架构中推荐的“发布-检索-绑定”模式，本文提出一个新的基于Web信息搜索的体系架构，并对其中空间元数据自动提取等关键技术进行了研究，最后通过原型系统进行验证。     

XML—WebGIS中空间信息共享和互操作的新途径

通过对现有空间信息共享技术的研究,利用最亲的XML技术,提出了一种新的解决空间信息共享的方法,设计了空间数据共享和互操作的整体框架,初步解决了地理空间信息（GSI）在Internet/Intranet上的发布、共享和互操作的问题。     

从五模块入手——基于空间数据库共享平台的数字城市方案

数字城市,从狭义上理解就是以3S技术和互连网技术为支撑的城市空间信息运行系统。它是一个包括城市空间信息运行机理、空间信息运行技术系统、空间信息服务与产业体系和社会文化在内的多层框架。数字城市工程是城市公用信息平台上的空间信息获得、更新、处理、应用系统。基于空间数据库共享平台的方正数码SDM数     

R树索引环境下空间信息服务平台的开发及应用

通过研究并实现空间信息服务平台,以解决数据共享和应用功能共享为主要目标。在数据共享上,采用了基于空间数据库的索引技术及基于地理标记语言（ GML）的数据交换技术;在应用服务上,采用基于Web服务的服务功能开发技术,从而满足空间信息应用（ Web、桌面系统及移动终端）的数据和功能需求。重点论述了基于R树索引技术进行空间数据的存储和检索,实现空间数据的快速检索,采用基于Web服务技术,实现空间信息应用功能共享,从而支持空间数据查询、获取及空间分析功能。最后以一个典型的土地规划应用为例,测试并论证了基于R树索引及空间信息服务技术的有效性。     

分布式异构地理分析模型共享门户的初步研究

针对目前GIS模型分析功能不足的困境,提出分布式异构地理分析模型共享门户的研究思路;基于地球系统科学理论,设计模型资源的分类组织体系,研究模型资源的表达形式和封装方法,突出语义和数据功能上的标准化;设计地理分析模型共享服务框架,以此克服分布式环境所引起的模型资源的访问障碍;构建了分布式环境下异构地理分析模型共享门户,并探讨该共享门户所具有的功能体系。     

基于GML的异构WebGIS空间信息共享研究

设计了一个基于GML的空间信息共享模型,给出了该模型所需要的关键技术,以此来对现有的WebGIS空间信息共享技术进行改进.该模型充分利用了现有网络和空间信息资源,较好地解决了异构WebGIS数据源的联合使用问题,同时具有良好的可扩展性.     

基于Web标准的信息港研究

数字城市是以Intemet为平台的,实现空间信息互操作为核心的城市信息管理系统,却受到跨行业应用的基础数据不同组织形式制约。数据的组织与表现松耦合关系是实现空间信息互操作的重要环节,也是适应语义网络计算标准的要求。Web标准将页面行为与表现分开,为信息港实现资源的一体化管理,满足用户按需的3A（Anybody,Anytime,Anywhere）视化服务,达到开放、共享根本目标提供了架构和实现的途径,同时隐含了制约信息港门户性能的关键问题和解决途径。     

县域地理空间信息平台电子地图发布与共享的方法

电子地图在县域地理空间信息平台的建设中具有重要作用。在分析传统电子地图发布主要以文件集的形式存储于服务器的不足基础上,探讨县域地理空间信息平台将电子地图以分布形式部署到各节点服务器中,利用瓦片金字塔技术来实现县域地理空间信息平台电子地图的网络发布,以达到电子地图的快速浏览和分节点存储数据的目的。通过地图瓦片、网络服务、地理信息服务技术,建立县域地理空间信息平台电子地图服务,为平台电子地图的数据发布与共享提供技术思路。     

基于Web Services的空间信息服务开放互操作模型

分析了现有WebGIS系统中存在的缺陷，指出无法实现异构空间数据的共享与功能上的互操作是阻碍Web-GIs进一步发展的两大障碍.开放式的WebGIS是今后的发展方向，本文基于最新的Web技术提出一个七层结构的分布式空间信息服务开放互操作模型，为解决现有WebGIS中的问题，构建以分布式空间信息服务为核心的基础信息服务平台做了理论上的探讨与研究。     

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。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

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.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.