平面时变向量场Hopf分岔的精确定位与可视化

分岔是指动力系统在演化过程中定性行为发生质变的现象．分岔研究对揭示复杂流场的不稳定过程有重要意义．文中提出一个平面时变向量场Hopf分岔的榆出、定位与可视化算法．通过精密跟踪场内全体临界点的变化以及用一个颜色模型图画般地记述这些变化的演化路径,新算法不仅实现了对平面时变向量场中全部Hopf分岔点的检出和定位,还能详尽显示分岔的发展过程,文中方法原则上也适用于其它局部分岔类型的检出,为用数据可视化技术观察和研究分岔现象开辟了新的途径。     

基于聚类的二维向量场可视化

已有的二维流场可视化中,鞍点等临界点是最重要的特征之一.文中从一个新的角度提出一种基于流线聚类的二维向量场可视化方法.首先生成采样流线集合,然后将流线聚类,最后引入共轭法向量场和流线密度矩阵对同一个类的流线进行加速排序.在此基础上,提出3种可视化应用:抽取每一类的代表流线进行向量场的流线简洁表达;根据流线之间距离进行多分辨率均匀流线表达;生成权值图,增强基于纹理的向量场可视化.实验结果表明,该方法具有良好的鲁棒性,可视化效果优于已有的方法.     

一种改进的相似重复记录检测方法

针对当前相似重复记录检测方法中存在的问题．提出一种改进方法．该方法根据关系表的决定属性值划分记录集,并在每个决定属性值类中检测相似重复记录．在决定属性值聚类时,提出了动态优先队列聚类算法和合并逆序算法．尽可能使相似重复的属性值聚为同一类;在记录聚类时提出了类调整算法,以提高类的代表记录的代表性．通过大量的实验分析,验证了该方法的有效性．     

基于自适应阈值的自动提取关键帧的聚类算法

利用无监督聚类算法来提取关键帧是一种常用的方法,但该算法对类别数和初始类划分较敏感,在对视频内容一无所知的情况下,要求预先指定聚类数目是一个很困难的问题．提出一种二次聚类的方法;第1次以镜头内相邻两帧的相似度为数据样本进行聚类（分成两类）,计算确定第2次聚类所需的阈值;第2次采用动态聚类的ISODATA算法,以视频序列的帧为数据样本进行聚类,得到最终聚类结果．最后在每类中自动提取距其类中心最近的帧为关键帧．该算法简单且行之有效,无需预定义任何阈值（如聚类数目）．对大量不同特点的视频进行了实验,该算法均取得了较好的实验结果．     

自动确定聚类中心的密度峰值算法

密度峰值聚类算法（Density Peaks Clustering,DPC）,是一种基于密度的聚类算法,该算法具有不需要指定聚类参数,能够发现非球状簇等优点。针对密度峰值算法凭借经验计算截断距离[dc]无法有效应对各个场景并且密度峰值算法人工选取聚类中心的方式难以准确获取实际聚类中心的缺陷,提出了一种基于基尼指数的自适应截断距离和自动获取聚类中心的方法,可以有效解决传统的DPC算法无法处理复杂数据集的缺点。该算法首先通过基尼指数自适应截断距离[dc],然后计算各点的簇中心权值,再用斜率的变化找出临界点,这一策略有效避免了通过决策图人工选取聚类中心所带来的误差。实验表明,新算法不仅能够自动确定聚类中心,而且比原算法准确率更高。     

基于划分的模糊聚类算法

在众多聚类算法中，基于划分的模糊聚类算法是模式识剐中最常用的算法类型之一．至今，献中仍不断有关于基于划分的模糊聚类算法的研究成果出现．为了能更为系统和深入地了解这些聚类算法及其性质，本从改变度量方式、改变约束条件、在目标函数中引入熵以及考虑对聚类中心进行约束等几个方面，对在C-均值算法的基础上得到的基于划分的模糊聚类算法作了综述和评价，对各典型算法的优缺点进行了实验比较分析．指出标准FCM算法被广泛应用的原因之一是它对数据的比例变化具有鲁棒性，而其他类似的算法对这种比例变化却很敏感．并以极大熵方法为例进行了比较实验．最后总结了基于划分的模糊聚类算法普遍存在的问题及其发展前景。     

基于加权K近邻的改进密度峰值聚类算法

密度峰值聚类算法是一种新颖的密度聚类算法,但是原算法仅仅考虑了数据的全局结构,在对分布不均匀的数据集进行聚类时效果不理想,并且原算法仅仅依据决策图上各点的分布情况来选取聚类中心,缺乏可靠的选取标准。针对上述问题,提出了一种基于加权K近邻的改进密度峰值聚类算法,将最近邻算法的思想引入密度峰值聚类算法,重新定义并计算了各数据点的局部密度,并通过权值斜率变化趋势来判别聚类中心临界点。通过在人工数据集上与UCI真实数据集上的实验,将该改进算法与原密度峰值聚类、K-means及DBSCAN算法进行了对比,证明了改进算法能够在密度不均匀数据集上有效完成聚类,能够发现任意形状簇,且在三个聚类性能指标上普遍高于另外三种算法。     

基于Small-World网络的非结构化DHT算法

目前,非结构化的P2P路由算法面临着搜索效率低下的严峻问题,这严重影响了非结构算法的应用领域．提出一种基于关键字聚类的分布式哈希表算法,主要思路是将环状关键字空间分成上下两层,下层(AUT层)负责关键字管理,上层(HUB层)负责节点路由．每个节点用一个随机数值作为它的聚类中心,从过往的路由消息中本地节点将抽取文件关键字和节点聚类中心,以聚类原则将这些数据记录到本地路由表中．除了改进非结构化算法的数据组织无序性,另一个目标是提高搜索效率．于是,上述算法的增强算法利用了small-world理论,在HUB层中加入远距离节点的聚类中心,将确定性聚类转化为概率性聚类,故能保证路由长度为O(log^2N)．     

与物理特征相关的平面向量场的拓扑简化及压缩

针对现有拓扑简化方法忽略物理特征保持的缺陷,提出一种对物理特征敏感的平面向量场拓扑简化算法,其中心思想是使用为应用定制的物理判据分类向量场区域,将向量场的特征检出与拓扑简化关联起来.通过合并次要物理特征所在区域上的网格及在新网格布局下重新提取向量场拓扑,该算法不仅能完好地保持场内的重要特征,还能同时实现向量场的数据压缩.实验结果表明,该算法在复杂流场的特征提取方面可发挥重要的作用.     

基于加权共享近邻与累加序列的密度峰值算法

密度峰值聚类（DPC）算法在对密度分布差异较大的数据进行聚类时效果不佳,聚类结果受局部密度及其相对距离影响,且需要手动选取聚类中心,从而降低了算法的准确性与稳定性。为此,提出一种基于加权共享近邻与累加序列的密度峰值算法DPC-WSNN。基于加权共享近邻重新定义局部密度的计算方式,以避免截断距离选取不当对聚类效果的影响,同时有效处理不同类簇数据集分布不均的问题。在原有DPC算法决策值的基础上,生成一组累加序列,将累加序列的均值作为聚类中心和非聚类中心的临界点从而实现聚类中心的自动选取。利用人工合成数据集与UCI上的真实数据集测试与评估DPC-WSNN算法,并将其与FKNN-DPC、DPC、DBSCAN等算法进行比较,结果表明,DPC-WSNN算法具有更好的聚类表现,聚类准确率较高,鲁棒性较强。     

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.     

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.     

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。