基于灰度差统计的角点检测方法

提出了一种新的基于灰度差统计的角点检测方法。该方法以原始图像全图的灰度差统计结果作为出发点，采用的灰度脊跟踪算法和累积角度判别原则不仅能提供角点的准确位置，还能确定各角点的开张角度和方向。由于省略了边缘检测过程，因此较大地提高了角点检测的效率。实验证明该方法应用在大部分真实图像的角点检测效果优异，同时运行速度能满足大部分角点检测应用的需要。     

基于粗糙集阴影区域的检测与分类

粗糙集理论是一种新的处理模糊和不确定性问题的数学工具。本文提出一种基于粗糙集阴影边缘分类方法。该算法根据粗糙集理论、梯度、最大邻域差及噪声的条件属性，将一幅图像划分为不同的子图像；然后对子图像分别进行处理，得到阴影边缘点；再利用边缘生长对边缘点进行细化和跟踪，删除那些假边缘点；然后根据阴影边缘构出假想的阴影区域，并统计这些区域的灰度直方图，求得阴影区域的灰度区间。根据该灰度区间可以得到阴影区域，再根据这些区域的灰度、形状、面积等特征对阴影进行分类。通过对所得结果进行分析可知，结合粗糙集理论的阴影图像边缘检测算法与其他的常规检测方法相比，无论从视觉效果还是检测精确度上都有所改善。     

一种基于变点统计分析的图像边缘检测的方法

基于统计的图像边缘检测方法是计算机视觉中边缘检测的重要方法之一。提出了一种基于非参数变点统计分析的方向性边缘检测算法,该方法可以最小化对图像数字特征的先验信息的需求。深入讨论该算法在含有高斯噪声和椒盐噪声的灰度图像处理中的一些问题,通过实验与MATLAB的经典的边缘算子sobel算子和canny算子相比较。该方法不仅能很好地检测出图像的真实边缘,而且有效地抑制了两种噪声对边缘检测的影响,取得了较好的效果。     

基于置信度融合的边缘检测性能评价基准图计算

针对边缘检测算法的性能评价，提出了一种在真实场景下基于统计、自适应强的评价基准图计算方法。定义了算法参数的相关系数，研究了算法参数相关模型。根据建立的算法参数相关系数得到单算法的预选基准图，对不同算法预选基准图进行基于置信度的图像融合得到可用于边缘检测算法性能评价的基准图。该计算基准图的方法有助于实现边缘检测算法性能评价的自动化，实验结果验证了该方法的有效性及实用性。     

一种基于积分变换的边缘检测算法

介绍了一种用于图象区域和边缘检测的积分变换。该变换引入了灰度尺度和空间尺度，从而将图象变为表示象素点相互吸引的向量场，将边缘检测问题转化为在向量场中寻找相分离向量的问题。通过分析该变换用于边缘检测而产生的一些问题，给出了使用图象局部信息估计灰度尺度的方法。在对已有方法简化和改进的基础上，提出了一个基于此变换的边缘检测算法。最后给出该方法的识别结果，并与经典的边缘检测算法做了比较。试验结果表明，其边缘检测效果与Canny算法相似，是一种有效的边缘检测方法。     

图像边缘检测的多尺度灰度Gap统计模型

汲取Hastie和Tibshiran i等人提出的“Gap statistic”的思想方法,利用样本灰度数据分布的差别定义多尺度的图像灰度间隙,在提出反分布函数概念的基础上,建立了图像边缘检测的多尺度灰度Gap统计模型。通过分析分布间隙和灰度间隙的一致性,优化了Gap统计模型的边缘检测算法。分析不同尺度下的检测结果,并比较了灰度Gap统计模型与Prew itt和Sobel边缘算子之间的相互关系。通过实例与分析,证明了该模型具有抗噪声、多尺度的特点。     

一种基于双边滤波的图像边缘检测方法

提出了一种基于双边滤波的图像边缘检测方法。利用图像像素的空间邻近度和灰度相似度的乘积来代替传统的Canny算法中高斯滤波的权系数，用该乘积与原图像进行卷积运算，然后通过非极大值抑制和高低阈值的方法检测出图像的边缘。基于双边滤波的图像边缘检测方法不仅有效地去除了图像中的噪声，而且很好地检测出了图像的真实边缘。     

一种基于边缘检测及纹理分析的水坝图像分割算法

针对边缘检测算法的局限性及灰度水坝图像的特点,提出了一种基于边缘检测及纹理分析相结合的灰度图像分割算法,首先利用边缘检测算法对待处理图像进行边缘检测得到图像的粗分割,然后在原灰度图像中对得到的边缘位置点进行纹理分析,去除检测到的非目标对象的边缘从而得到分割图像,即细分割。将该算法应用到河坝监测系统中,实验证明该算法达到了很好的分割效果。     

新的噪声污染灰度图像边缘检测统计方法*

针对传统算子进行边缘检测时易丢失边缘信息和在非边缘处增强噪声的缺陷,提出一种基于非参数变点统计分析的噪声图像边缘检测方法,该统计方法不但不需要图像数字特征的任何先验信息,而且对噪声污染的图像不作任何滤波处理.实验结果表明,提出的算法优于Sobel算子,并能抑制信噪较低的高斯噪声和密度较高的椒盐噪声对分割结果的影响,是一种有效的噪声污染灰度图像边缘检测方法.     

基于灰预测模型的边缘检测新方法

提出了一种基于灰预测理论的边缘检测新方法。该方法基于GM(1,1)模型，根据图像不同区域间灰度级有较大变化的特性，由同行(列)待检测像素之前的若干像素灰度值建立灰预测模型，并利用模型预测此像素灰度值，比较预测灰度值与实际灰度值之间的差值，由差值来判断该像素是否为边缘像素。通过对不同类型测试图像利用本算法进行边缘检测效果比较表明，该算法能取得比较好的效果。     

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.