数据库中关系代数除法运算的教学研究

关系代数中的除法运算是数据库课程中的难点问题。文章从关系代数除法运算的定义出发,以实例为牵引,通过类比整数的除法运算,阐明关系代数除法运算的本质,给出除法运算的基本运算表达方法并用SQL语句实现,突破除法运算的难点,以期取得较好的教学效果。     

由容差关系挖掘块关系的亏值运算方法研究

形式概念分析是一门进行知识发现和数据分析的重要理论,已经被广泛应用于各种领域。容差关系和块关系是形式概念分析中的重要内容,在介绍了形式概念与分析中相关基本理论的基础上,从概念间亏值的角度出发,通过亏值运算可以实现由给定的容差关系找出与之对应的块关系,为亏值理论在形式概念与分析知识体系中的结合与应用提供了扩展和思路。     

关系代数中除法运算的表示

本文主要讨论了用基本运算表示除法运算的关系代数表达式。用图形法作为分析工具,给出了关系代数中除法运算的查询原理,解决了以往用抽象定义进行除法运算的难度,结合实例提出了讲授这些知识点的一些新思路和新方法,取得了较好的教学效果。     

关系代数中除法运算的表示

本文主要讨论了用基本运算表示除法运算的关系代数表达式.用图形法作为分析工具,给出了关系代数中除法运算的查询原理,解决了以往用抽象定义进行除法运算的难度,结合实例提出了讲授这些知识点的一些新思路和新方法,取得了较好的教学效果.     

基于坐标映射模型的方向关系一致性检验

为处理复杂三维空间物体间的方向关系,基于单纯形数据模型,利用投影方法及区间运算简单的特性,提出三维空间物体方向关系的坐标映射模型。在此基础上,讨论三维空间方向关系的基本推理运算、凸关系判断方法及路径一致性检验算法,给出方向关系网络一致性检验算法及其正确性证明。     

关系代数中除法运算的教学探讨

从关系代数中除法运算的定义出发,以实例分析和图表表示为工具,通过类比整数的除法运算阐明关系除法运算的本质含义,并给出关系代数中除法运算的基本运算表达式。解决以往除法运算的抽象定义难以被学生理解的不足,促进学生对知识点的透彻理解,取得较好的教学效果。     

关系代数中交运算与差运算的SQL语句实现

关系代数是关系数据操纵语言的一种传统表达方式，是结构化查询语言SQL的重要理论基础。然而关系代数8种常用运算中的交运算、差运算和除运算，在SQL中没有提供专门的运算符加以实现，不利于初学者更好的理解关系代数和SQL之间的关系。本文针对这一现状，对交运算、差运算在SQL中的实现方法进行探讨。     

基于矩阵的粗糙集上、下近似求解算法*

针对粗糙集中上、下近似集的求解问题,根据关系的矩阵表示和矩阵运算具有简便直观的特点,提出了一种利用关系矩阵和基本的矩阵运算计算上下近似的方法,通过理论证明结果显示该方法是可行有效的。     

模幂与点乘m_ary算法中窗口大小的最优化估计

提出一种新大数模幂与点乘m_ary算法中窗口大小的最优化估计方法.该方法不同于传统的暴力搜寻方法,也不同于在窗口的取值范围内通过逐一测试程序来获得最优窗口大小的方法.其基于以下理论分析:模幂 m_ary算法的基本运算为大数乘法,其中包括大数平方算法和一般大数乘法;椭圆曲线加密算法中点乘的m_ary算法步骤与模幂的m_ary算法相同,后者的基本运算为倍乘和加法.根据m_ary算法的基本运算的调用次数,推算出了最优窗口大小的估计公式.通过实验对m_ary算法进行实现,并测试分析了根据估计公式计算出窗口大小的算法实现时间效率与理论分析基本吻合.     

Rough集理论中知识与运算的矩阵表示

同一问题在不同知识表示下算法难度不同。Rough集理论把知识定义为对对象的分类能力,并提供了一套基于代数系统的知识表达和处理方法。然而在代数表示下,知识的本质以及运算直观性较差,不易于理解。同济大学苗夺谦教授建立了知识与信息之间的关系,在此基础上给出了Rough集理论中概念和运算的信息表示,并给出了知识约简在代数和信息两种表示下的等价性证明。现进一步将知识及其运算表示成粒矩阵形式,继而给出了知识约简在代数、信息和粒矩阵3种表示下的等价性证明。     

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。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。