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基于动态时间弯曲的时序数据聚类算法的研究 总被引:14,自引:0,他引:14
时间序列是一类重要的复杂类型数据,时间序列知识发现正成为知识发现的研究热点之一。欧几里的距离及其扩展作为相似测度被广泛应用于时间序列的比较中,但是这种距离测度对数据没有好的鲁棒性。动态时间弯曲技术是基于非线性动态编程的一种模式匹配算法。该文提出了基于动态时间弯曲技术的相似搜索算法,通过计算时序数据之间的最短弯曲路径来获得序列的匹配。对综合控制时序数据进行基于不同距离测度的聚类分析对比结果表明该文提出的算法有很高的精度和对振幅差异、噪声和线性漂移有强的鲁棒性,具有良好的应用价值。 相似文献
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针对时间序列相似性度量中欧氏距离对异常数据敏感以及DTW距离算法效率低的问题,提出基于滑动平均与分段线性回归的时间序列相似性方法。首先,使用初始可变滑动平均算法以及分段线性回归对原始时间序列进行数据变换,并将分段线性回归的参数(截距与距离)集作为时间序列的特征,以实现时间序列的特征提取和数据降维;然后,利用动态时间弯曲距离进行距离计算。该方法在时间序列相似性上与DTW算法的性能相近,但是在算法效率上几乎提高了96%。实验结果验证了该方法的有效性与准确性。 相似文献
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时间序列的相似性搜索是时间序列知识发现的重要方面。该文提出了一种新的基于距离度量的时间序列相似性搜索算法。该算法采用分段线性表示,同时使用改进的模式距离来度量序列间的距离。 相似文献
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针对时间序列数据,提出一种新的基于动态时间弯曲的下界技术,该技术首先基于分段聚集近似的线性表示对原始序列进行降维,同时生成查询序列的网格最小边界矩形近似表示,然后利用基于动态时间弯曲距离对两者下界距离度量。实验结果表明,该下界技术与以往相关技术相比,能够产生更大的下界距离,具有更强的紧凑度、裁剪搜索空间能力以及更短的运行时间,有利于时间序列数据挖掘。 相似文献
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针对常用方法无法准确度量多元时间序列相似程度的问题,提出一种基于多维分段和动态权重动态时间弯曲距离的多元时间序列相似性度量方法.首先对多元时间序列进行多维分段拟合,选取拟合段的斜率、均值和时间跨度作为每一段的特征,在对多元时间序列降维的同时也保留了变量之间的相关性;然后提出一种动态权重动态时间弯曲距离度量方法计算多元时间序列特征矩阵之间的距离,避免了直接使用动态时间弯曲距离造成的畸形匹配问题.最终实验结果也验证了该方法在多种类型的数据集上都能取得较高的度量精度,表明了该方法的有效性. 相似文献
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基于时间序列的相似子模式发现算法 总被引:4,自引:0,他引:4
基于时问序列的数据挖掘时,一般需要对时间序列离散化,再聚类成不同的子模式。已有的方法常忽略时间序列本身的位置和整体特征,并且计算量大。针对其不足,文中提出一种检索时间序列分段关键点的算法,以关键点为边界分段,使用形态距离测度和快速剪除的算法,高效简便地检索出相似子模式。 相似文献
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基于分段时间弯曲距离的时间序列挖掘 总被引:22,自引:1,他引:22
在时间序列库中的数据挖掘是个重要的课题,为了在挖掘的过程中比较序列的相似性,大量的研究都采用了欧氏距离度量或者其变形,但是欧氏距离及其变形对序列在时间轴上的偏移非常敏感.因此,采用了更鲁棒的动态时间弯曲距离,允许序列在时间轴上的弯曲,并且提出了一种新的序列分段方法,在此基础上定义了特征点分段时间弯曲距离.与经典时间弯曲距离相比,大大提高了效率,而且保证了近似的准确性. 相似文献
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This paper presents a novel approach to the problem of time periodization, which involves dividing the time span of a complex dynamic phenomenon into periods that enclose different relatively stable states or development trends. The challenge lies in finding such a division of the time that takes into account diverse behaviours of multiple components of the phenomenon while being simple and easy to interpret. Despite the importance of this problem, it has not received sufficient attention in the fields of visual analytics and data science. We use a real-world example from aviation and an additional usage scenario on analysing mobility trends during the COVID-19 pandemic to develop and test an analytical workflow that combines computational and interactive visual techniques. We highlight the differences between the two cases and show how they affect the use of different techniques. Through our investigation of possible variations in the time periodization problem, we discuss the potential of our approach to be used in various applications. Our contributions include defining and investigating an earlier neglected problem type, developing a practical and reproducible approach to solving problems of this type, and uncovering potential for formalization and development of computational methods. 相似文献
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James A. Ward 《Information Systems Management》1994,11(3):75-78
Total quality management is a commitment to the continuous improvement of work processes with the goal of satisfying internal and external customers. It's the customer that matters in TQM; the process is only the means to satisfying the customer. 相似文献
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James A. Ward 《Information Systems Management》2013,30(3):75-78
Abstract Total quality management is a commitment to the continuous improvement of work processes with the goal of satisfying internal and external customers. It's the customer that matters in TQM; the process is only the means to satisfying the customer. 相似文献
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六通 《数码设计:surface》2012,(8):142-146
运动是人类爆发的本能。完美形态的塑造与身体能量的释放,让运动总是充满了魅力。腕表与运动结缘已久,正因为它们都崇尚耐力、精准、强壮。而今,运动腕表已成为庞大的家族。 相似文献
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Eduardo Kac 《AI & Society》2000,14(2):243-249
Time Capsule is a work-experience that lies somewhere between a local eventinstallation, a site-specific work in which the site itself is both my body and a remote database, a simulcast on TV and the Web, and interactive webscanning of my body. The live component of the piece was realised on November 11, 1997, in the context of the exhibition Arte Suporte Computador, at the cultural centre Casa da Rosas, in Sao Paulo, Brazil. Time Capsule was carried live on the evening newscast of the TV station Canal 21 and on tape by two other TV stations (TV Manchete and TV Cultura). The webscast was transmitted by Casa das Rosas.The object that gives the piece its title is a microchip that contains a programmed identification number and that is integrated with a coil and a capacitor, all hermetically sealed in biocompatible glass. The temporal scale of the work is stretched between the ephemeral and the permanent; i.e., between the few minutes necessary for the completion of the basic procedure, the microchip implantation, and the permanent character of the implant. As with other underground time capsules, it is under the skin that this digital time capsule projects itself into the future. 相似文献
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Intemet中常见的时间同步方法有两种,GPS法和NTP法。GPS法精度高,但价格昂贵且受自然条件影响;N11P法简单易用.但精度较低无法满足一些特殊场合的需求。相对于Intemet,专用网络可以为时间同步做出一些专门的设置,从而保证较高的时间同步精度。本文针对IP专用网络,提出了一种时间同步方法。该方法综合了GPS法和N11P法的优点,在降低成本的同时能够保证较高的同步精度。 相似文献
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单机模糊加工时间下最迟开工时间调度问题 总被引:1,自引:0,他引:1
研究单机模糊加工时间下确定最迟开工时间的调度问题。目标是在满足每个工作都以大于等于各自指定的隶属度属于完工集合的约束下,建筑工作的最大最迟开工时间。通过模糊数学知识对模型进行分析,对于特殊情况给出了问题的最优解,对于一般情况给出了一个最优解的必要条件。 相似文献
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滑动聚集平均近似PAA(Piecewise Aggregate Approximation)是一种表示时间序列的方法,它通过时间序列上滑动一个等宽的滑动窗口将时间序列分成小的区段。考虑到时间序列的时间特性q-不同区段的影响,本文提出了一种改进表示RPAA(Reversed Piecewise Aggregate Approximation)。RPAA表示对处于不同时间段的序列赋以不同的影响因子,具有线性时间复杂度,并且证明了RPAA满足下界定理,因而能够进行实际的查询。最后的实验表明该表示是有效的。 相似文献
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Extraction of sequences of events from news and other documents based on the publication times of these documents has been
shown to be extremely effective in tracking past events. This paper addresses the issue of constructing an optimal information preserving decomposition of the time period associated with a given document set, i.e., a decomposition with the smallest number of
subintervals, subject to no loss of information. We introduce the notion of the compressed interval decomposition, where each subinterval consists of consecutive time points having identical information content. We define optimality, and
show that any optimal information preserving decomposition of the time period is a refinement of the compressed interval decomposition.
We define several special classes of measure functions (functions that measure the prevalence of keywords in the document set and assign them numeric values), based on their effect
on the information computed as document sets are combined. We give algorithms, appropriate for different classes of measure
functions, for computing an optimal information preserving decomposition of a given document set. We studied the effectiveness
of these algorithms by computing several compressed interval and information preserving decompositions for a subset of the
Reuters–21578 document set. The experiments support the obvious conclusion that the temporal information gleaned from a document
set is strongly dependent on the measure function used and on other user-defined parameters.
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Daniel J. RosenkrantzEmail: |