基于局部均值分解和改进小波熵的时序SAX模型

符号聚合近似表示法是提取时间序列特征的重要方式。然而,传统的符号聚合近似表示法存在平均化分段数、同等对待划分区间,以及无法准确反映非平稳序列的突变信息等多项缺陷。鉴于此,通过引入局部均值分解和改进小波熵的分段算法,建立了一种新的时序SAX模型。该模型的基本原理是采用局部均值分解技术对原始序列进行去噪处理,利用滑动窗口阈值法获取分段数,并使用SAX表示法进行符号表示,利用KNN分类器实现分类性能测试。基于这一改进模型,进行了实证检验,实验结果表明,该模型能够有效提取序列的信息特征,具有较高的拟合度,达到了降维的目的,更重要的是,提高了KNN分类算法在SAX表示法中分类的准确率。     

基于符号化表示的时间序列频繁子序列挖掘

提出一种新的基于符号化表示的时间序列频繁子序列的挖掘算法。利用基于PAA的分段线性表示法进行降维,通过在高斯分布下设置断点,实现时间序列符号化表示,利用投影数据库挖掘频繁子序列。该算法简单、新颖,运行快速,简化了子序列支持数的计算。     

交叉熵相似性度量在水文时间序列匹配中的应用

基于交叉熵的相似度查询算法利用小波变换对数据进行预处理,通过PAA算法对数据进行降维,求得降维后的水位数据的近似概率分布情况。通过交叉熵距离来度量两个序列间的概率分布差异。以鄱阳湖星子站日水位数据为例,验证了基于交叉熵的相似度查询算法在降低时间复杂度的前提下较准确地找出给定时间段相似的水文过程。     

基于云模型的时间序列分段聚合近似方法

针对时间序列数据的高维特性,提出一种基于云模型的时间序列分段聚合近似方法.利用云模型的熵评判分段聚合后各子序列的数据稳定性,选取稳定性最弱的子序列再分段聚合,最终得到云模型序列,同时给出了云模型序列的相似性度量.该方法对时间序列能够有效降维,并能够自适应地识别和描述其基本特征.实验结果表明,数据压缩较大时,所提出方法能够较好地保证近似的准确性,并提高时间序列数据挖掘的效率.     

基于趋势特征的时间序列符号聚集近似表示方法

针对时间序列数据降维过程中易丢失趋势特征信息的问题,提出一种基于趋势特征的时间序列符号聚集近似表示方法,除保留各序列分段的均值特征外,采用分段的趋势距离因子及趋势形态因子共同描述序列趋势特征;并给出了满足下界密封性的距离度量方法,从而更好地表示具有不同趋势特征的时间序列。在公共数据集上的实验结果表明,该方法在分类误报率、降维比率等方面比符号聚集近似方法（SAX）和基于趋势距离的时间序列符号近似表示方法（SAX＿TD）有10%以上的下降,并具有更好的下界密封性。实验结果证明,该算法在进行时间序列压缩的同时充分保留时间序列的趋势变化形态,从而提高时间序列数据挖掘的效率。     

基于形态特征的时间序列符号聚合近似方法

由于形态特征能够较为客观地反映时间序列的变化趋势,在时间序列数据降维过程中,形态特征的提取能够保留较为充分的数据信息,为提高后期的时序数据挖掘的效率提供可靠的保障。文中提出基于形态特征的时间序列符号聚合近似方法,综合考虑分段序列的均值和数据分布的形态特征,并且通过论域转化对它们实现符号转化。在相同的压缩比环境下,与传统符号化表示方法相比,该方法能更好地提供原始时间序列数据信息,进而提高时间序列数据挖掘的效率。     

基于二分迭代SAX的时序相似性度量算法

时序降维是解决时间序列高维问题的关键技术。符号聚集近似表示(SAX表示法)作为一种时序降维技术,具有良好的维度约简能力与性能稳定的下界距离算法,但算法中分段数的选取需根据当前时序数据的特征而人为设定。针对这一问题,引入了滑动窗口算法与统计学方法,提出了基于二分迭代SAX的时序相似性度量算法。实验结果表明,该算法不仅解决了分段数设定困难的问题,而且降低了时序降维表示的复杂度,提高了SAX算法在多种时序数据上的分类准确性。     

基于PAA的时间序列早期分类

在时间序列数据挖掘领域,时间序列的早期分类越来越受到人们的重视,由于时间序列的长度(也称为维数)较大,在早期分类的实际应用中选择合适的维数约简方法非常重要,因此提出一种基于分段聚合近似(PAA)的时间序列早期分类方法。首先运用PAA对时间序列样本进行维数约简,然后在低维空间对样本进行早期分类,在43个时间序列数据集上的实验结果表明, 所提方法 在准确率、早期性、可靠性等方面优于已有方法。     

基于符号化聚合近似的时间序列相似性复合度量方法

基于关键点的符号化聚合近似(SAX)改进算法(KP_SAX)在SAX的基础上利用关键点对时间序列进行点距离度量,能更有效地计算时间序列的相似性,但对时间序列的模式信息体现不足,仍不能合理地度量时间序列的相似性。针对SAX与KP_SAX存在的缺陷,提出了一种基于SAX的时间序列相似性复合度量方法。综合了点距离和模式距离两种度量,先利用关键点将分段累积近似(PAA)法平均分段进一步细分成各个子分段;再用一个包含此两种距离信息的三元组表示每个子分段;最后利用定义的复合距离度量公式计算时间序列间的相似性,计算结果能更有效地反映时间序列间的差异。实验结果显示,改进方法的时间效率比KP_SAX算法仅降低了0.96%,而在时间序列区分度性能上优于KP_SAX算法和SAX算法。     

时间序列数据降维及特征表示新方法

数据降维和特征表示是解决时间序列维灾问题的关键技术和重要方法, 它们在时间序列数据挖掘中起基础性作用. 鉴于此, 提出一种新的时间序列数据降维和特征表示方法, 利用正交多项式回归模型对时间序列实现特征提取, 结合特征序列长度对时间序列的拟合分析结果, 运用奇异值分解方法对特征序列进一步降维处理, 进而得到保存大部分信息且维数更低的特征序列. 数值实验结果表明, 新方法可以在维度较低的特征空间下取得较好的数据挖掘聚类和分类效果.

     

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     

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。