数据库服务器与WWW之间的一种集成设计

本文根据WWW用户和数据库用户各自对数据访问的特点不同,提出了一种将数据库服务器与WWW集成的结构。该集成结构中既提供了基于超文本的导航浏览功能访问数据库系统,又支持用户直接利用数据库系统本身的查询界面,快速查询数据对象。     

多数据库系统中查询分解算法的研究

多数据库系统允许用户使用一个集成模式和简单的全局查询语言同时访问多个异构的、自治的数据库系统。全局查询分解处理是多数据库系统中的一个很重要的问题。本文给出了一种多数据库环境中的模式信息管理方法,基于这些模式信息,我们提出一种易于实现的查询分解算法。由于多数据库查询分解处理与模式集成的实现紧密相关,所以本文对多数据库系统的模式集成作了一些描述。     

一种适合多数据库系统的查询表示方法

1 引言随着分布计算和网络技术的不断发展,传统的数据库技术已越来越不能满足数据共享和互操作的需要。同时,已有的数据库系统又不可能全部丢弃.因而研制能同时访问和处理来自多个数据库中数据的多数据库系统已成为必然趋势。多数据库系统是解决已存的、异构的、分布的多个局部数据库系统之间数据共享和集成的问题。由于多数据库系统具有异构性、分布性和局部自治性的特点,使得多数据库查询处理与传统数据库查询处理有很大的不同。多数据库系统呈现给用户的是全局模式,用户使用全局查询语言提交对多数据库的查询,而所需的数据又必须从各局部数据库获得,所以必须将全局查询转换成与局部数据库对应的局部查询。在全局查询转换为局部查询的过程中,需要     

WWW与数据库集成系统的用户权限管理

在WWW上的应用,越来越多的体现为多人合作应用形式,这些应用系统大多都需要通过WWW与数据库的集成来实现。但是由于WWW与数据库系统都有自己的用户权限管理,因此集成后在用户管理、权限设定及系统完整性方面就产生了一些问题。文章针对WWW与数据库集成系统,提出用户权限管理结构和机制,并设计了实际系统模型,它将服务器对用户的认证,转变成基于用户角色的对数据库的访问控制,不但能保护WWW与数据库的数据,而且能确保系统结合的完整性,同时更可以大量简化用户管理与权限管制的工作,提高权限管理的效率。     

基于CORBAWEB的异构数据库联合使用

未来对各种异构数据库系统的使用将包括WWW环境和CORBA标准,结合WEB和CORBA技术,可以给用户提供具有友好界面的、面向对象的和高效率访问异构数据源的应用。本文讨论了数据库技术、WEB技术和CORBA技术的集成,并进一步阐述了如何使用CORBA技术访问网络上的异种数据库和这种技术的优势以及应用前景展望。     

对WEB数据查询分页显示的设计与实现

在用B/S三层结构实现的网络系统中,必须使用数据库技术。用户通过浏览器IE和INTERNET浏览网站信息时,可能会访问大量数据库数据,但是网络连接常因速度缓慢或因超时而产生中断。针对此种问题,提出如何采用ASP中的ADO技术实现WWW数据库访问,以及如何实现数据的分页传输和显示。实践证明分页传输和显示的方法能实现定位任何一页的查询功能,大大降低了连接时间,提高了查询的效率。采用该方法实现数据查询在实际应用中已取得了良好的效果。     

安全数据库隐私保护和访问控制集成研究*

数据库数据的合法使用和隐私保护是现代安全数据库系统面临的新挑战。针对目前单方面考虑隐私保护或访问控制技术难以同时满足数据库信息安全和处理性能需求的不足,提出一种集成访问控制和隐私保护技术的安全数据库模型,通过建立查询审计隐私保护模型中的查询可疑性与授权视图访问控制模型中查询有效性之间的关系,形成统一的查询判断方法,并给出多项式时间复杂度的审计算法和集成的安全检查框架,以同时实现数据库系统隐私保护和访问控制的安全功能。     

面向数据库查询加速的异构体系结构设计与实现

数据库是数据分析、人工智能、云计算和大数据等领域的关键工作负载,是提高系统整体性能的关键。传统数据库系统查询执行效率偏低,并且CPU通常需要优先处理事务性负载,使数据查询逐渐成为制约整个数据库系统性能和效率提升的瓶颈。为了提高数据库在大规模并发访问时的数据处理能力,提出了一种CPU+FPGA加速数据库查询的异构体系结构,通过使用异构缓存一致性加速接口将加速器集成到CPU中,在FPGA内定制可配置的多引擎查询方式,对数据库查询进行加速。聚焦常用的SQL查询语句SELECT,详细分析了系统在延迟和简化的软件堆栈方面的优势,最后使用浪潮F37X加速卡和浪潮服务器对加速模型功能和性能进行了验证。实验结果表明,与使用POWER 9 CPU进行同样的查询操作相比,数据库系统整体处理速度提高了3～9倍,这种先进的异构计算加速结构可应用在未来数据库硬件专业化的设计中。     

WEB日志实时规则数据库的查询

随着WWW应用的高速发展和广泛普及,WWW服务器上收集大量的Web日志。对这些日志进行实时的数据开采,可得到大量关联规则,这些规则存放在实时规则数据库中。为了能即时并准确得到最能反映当前用户访问模式的规则,我们需要一套建立在规则形式基础上的查询和触发器系统,从实时规则数据库中,分析出Web用户当前访问模式的变化趋势。     

编程疑难问题解答

Q怎样利用PB的OLE技术变Word为单纯的文档浏览器A在设计某大型数据库系统时,用户提出了这样的要求：除了要对大量的数据进行存储、处理和查询外,还要求把描述这些数据的测试过程、处理方法等技术细节的大量技术文件也集成在数据库系统中,以供数据库的使用者查询。但使用     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

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。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

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.