基于经验模式分解的时间序列预测方法研究

支持向量机理论是20世纪90年代由Vapnik提出的一种基于统计学习理论的新的机器学习方法,其具有全局最优解和较好的泛化能力,可将其用于求解时间序列预测间题.但是对于非平稳时间序列的顶测,利用支持向量机算法单独建立一个模型的预测结果不如平稳时间序列那样明显,可以采用经验模式分解法作为时序预测的预处理工具.先将非平稳时间序列进行经验模式分解,再对各个分量分别建模,最后将各分量预测结果进行组合.同时通过仿真实验验证了该方法是有效的.     

一种基于超统计理论的非平稳时间序列异常点检测方法研究

从非平稳时间序列的分布函数及其参数入手,主要研究分布函数不变分布参数变化的这一类非平稳的时间序列异常点检测方法,提出了基于超统计的异常检测方法,并将其应用于非平稳网络流量时间序列。从网络流量的非平稳和突发性特点出发,特别考虑到由于攻击流量所引起的流量特性的变化,结合超统计理论,主要研究分布参量的变化。根据超统计的理论,先应建立分布统计模型,研究分布模型不同参数变化对分布的决定性作用,从而将异常网络流量的检测研究转化成对慢变量参数序列的检测研究。该检测方法大大降低了计算的复杂度。通过大量实验表明该方法具有良好的效果。     

基于趋势相似性特征的异常工况监测方法研究

当前火力发电生产过程中,多元变量检测方法难以实现多元非平稳过程变量异常工况监测。对此,首先计算多元变量之间在固定时间窗口宽度内数据之间的趋势相似性,采用所得到的趋势相似性作为监控特征。其次,采用主元分析方法对所得到相似性特征序列进行降维,对降维后所得到的主元空间趋势相似性特征序列进行监控。最后,以T2统计量作为监测指标,依据T2统计量与其控制阈值T2α的大小关系产生告警信号,从而达到有效监控多元非平稳过程变量的目的。通过在华北电网某300 MW火电机组的应用,验证了所提出方法的有效性与可靠性。该方法较好地解决了多元非平稳过程的检测问题,对于相关研究与应用具有借鉴意义。     

基于主成分分析的模糊时间序列模型的平稳化算法

在模糊时间序列模型建立的过程中,对数据的预处理和模糊规则的优化往往是影响模型预测精确度的关键因素.针对上述问题,提出基于主成分分析(PCA)的平稳化算法.首先,对数据进行平稳化检验,并将非平稳的数据进行预处理使其平稳;其次,对论域进行划分并根据模糊关系构建广义的协方差矩阵,由此计算广义协方差矩阵的特征值和特征向量;再次,根据特征值的累计贡献率优化模糊规则,利用优化后模型进行预测;最后,通过实际算例验证新算法的可行性.     

面向临床检验指标的非同步时间序列聚类算法研究

对临床检验指标时间序列进行聚类,从中发现临床检验指标变化趋势相似的患者群体,对开展精准医疗具有非常重要的价值。考虑到不同患者的检验次数及检验时间点不完全同步,首先通过对非同步时间序列进行预处理,实现不同时间序列维度及时间点的同步化。在此基础上,通过引入一个用户自定义参数即噪声点占有率NoisePro,对DBScan算法进行改进,提出了一种基于密度划分思想的非同步临床检验指标时间序列聚类LabTS-CLU算法。最后利用某三甲医院十余万糖尿病患者近10年的糖化血红蛋白时间序列数据集进行实验,结果证明了所提算法的有效性。     

基于流分解的异常检测算法

通过研究网络异常检测,提出了一种基于流分解消除网络噪声的异常检测算法。该算法从高维、非平稳流量中分离出包含异常的随机部分,通过计算随机部分参数的边缘分布和残差,揭示了流量异常对随机部分参数的影响,并提出判断网络流量异常的参数标准。实验表明,由于不必将整个时间序列进行分片和单独拟合,算法可以直接处理非稳态流量数据,实现了真正意义上的网络异常检测功能。     

基于Teager算子的短时HRV样本熵算法

在心率变异性(HRV)数据的短时非线性分析中,单纯的样本熵算法不能有效提取健康人和充血性心衰(CHF)患者的信号特征差异。为此,提出一种基于Teager 能量算子的样本熵分析算法。采用Teager算子的预处理捕获心脏动力学活动中的异常节律变化,以强化样本熵分析效果。对MIT-BIH数据库中样本的实验结果表明,该算法可反映健康人与CHF患者的短时HRV信号非线性复杂性的差异,为计算机分析诊断心衰等疾病提供新的辅助依据。     

基于77GHz毫米波雷达的非接触式精确心跳检测

基于多普勒雷达的非接触式心跳检测对于一些特殊场合有着重大的实用价值.然而,准确且快速的心率检测仍面临两大挑战:呼吸的强干扰以及心跳频谱分辨率不足.本文提出了一种基于77 GHz毫米波雷达的心跳检测方法,用于估计心率(HR)和心率奇异性(HRV).首先,提出了一种基于自适应变分模态分解(AVMD)的方法,在呼吸强干扰下精...     

基于隐马尔科夫模型的非平稳信源参数估计

在数据压缩领域,如何获取非平稳信源的统计特性一直是一个被广泛关注的热点问题。针对非平稳信源统计特性的时变性,提出一种基于隐马尔科夫模型的参数估计方法。通过将非平稳信源的输出对应为隐马尔科夫模型的观察值序列,构造合适的隐马尔科夫模型,改进前向算法和后向算法,最后再利用改进后的算法对非平稳信源的统计特性进行估计。实验结果表明利用提出的方法非常逼近非平稳信源的统计特性,为更有效地进行非平稳信源的压缩提供了实现基础。     

心电信号去噪的数学形态学滤波器

为探索验证一种基于数学形态滤波器的去除心电基线漂移和工频干扰的高性能滤波器设计方法,借鉴数学形态学一维信号滤波原理,提出自适应阈值ECG去噪算法的思路,讨论了3σ统计准则在ECG自适应阈值滤波中的作用,利用改进的算法对心电图中常见的工频干扰和基线漂移进行校正。通过对MIT-BIH心率变异数据库中多组数据的仿真验证研究,验证了该算法能有效实现心电信号的噪声预处理;数学形态学理论在心电信号处理中具有良好性能,是实时处理一维生物医学信号有潜力的工具。     

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。