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Nondimensionalization of variables enables us to treat experiment data much more simply and efficiently by decreasing the
number of variables. In some cases, trivial conclusions (which Kenney, 1982, called spurious self-correlation) result from
a formal application of dimensional analyses. In contrast, in some cases fully significant conclusions can be derived. We
first discuss how to construct nondimensional variables retaining the physical meanings of variables. We then propose simple
and efficient methods, especially the use of “spurious triangle (SpT)”, to discriminate between significant conclusions and
spurious self-correlations in the analysis of nondimensionalized variables. 相似文献
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Empirical power laws are frequently used to relate parameters in complex hydrological and hydrometeorological processes. The validity of power laws relating two parameters with a common variable may be compromised by spurious influences of the common variable. Theoretical results are presented that allow both the spurious self-correlation coefficient and the slope of a spurious self-correlation to be determineda priori. Raising a common variable to a higher power in either parameter amplifies the spurious effects.Power law regression equations are not single-valued analytical functions and must not be treated as such. Because of the strong influence of a common variable on the correlation coefficient, the transfer of a common variable from one side of a power-law regression equation to another (by cross-multiplying) may severely distort the results. Examples from lake hydrology are presented. 相似文献
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我国轨道交通已经进入新建与维护并重期。随着地铁隧道服役年限的增加,其病害种类不断增加,且各类病害呈逐渐加重的趋势。以三维激光测量隧道逐环监测数据为基础,研究隧道区间的病害空间分布特征和自相关性,全面掌握地铁隧道运营状态和病害发展趋势,是进行隧道病害防治的前提。本文利用某地地铁上行线隧道逐环三维激光测量数据,分析了错台、掉块、裂缝和渗漏水等病害在线路走向的空间分布特征,分析了病害与周边地质环境的关系。利用灰色关联分析算法研究了病害之间的相关性,为掌握隧道病害的发展趋势和认识病害之间的耦合关系建立了定量化的分析手段。本文为掌握隧道病害空间分布规律,预测隧道病害的发生、治理提供了有效依据,可以为地铁安全运营提供有力保障。 相似文献
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提出了隐含语义相关性分析的处理方法,对描述视频内容结构的视频文档矩阵进行奇异值分解和变换,可得到表达可视特征与语义间隐含相关性的关系矩阵,用于视频检索。分析和实验表明,所提出的方法能保留视频内容结构中核心的语义元素,消除冗余的相关性干扰,还能够通过矩阵降维减少计算量,改善视频语义内容检索的效果。 相似文献
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SHIFTING SELF-CORRELATION METHOD INITIALY USED IN THE APPARENT RESISTIVITY OBSERVATION DATA 
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下载免费PDF全文 In this paper,we propose a method of seismic prediction using the geo-electric resistivity shifting self-correlation (SSC),and a numerical test is carried out using random time series analysis to verify the validity of the method.The SSC method is applied to the actual observation data of three geo-electric resistivity stations,and results are obtained as follows:(1) SSC coefficient changes in Ganzi and Shandan stations have good correspondence to earthquake,which is represented mainly by the phased increase of correlation coefficient appearing six months to a year before the earthquake.At the same time,the correlation coefficient anomalies of the two stations also exhibit strong anisotropy.(2) Although Chengdu geo-electric resistivity station had suffered serious disturbance,the correlation coefficient anomaly also has a good correspondence with earthquake.In addition to the validity of the SSC method,it may also be attributed to the magnitude of the earthquake event,the smaller distance of epicenter,and the time of the earthquake.Anisotropy also exists in the anomaly at Chengdu station.(3) By comparing the characteristics of different magnitudes of earthquakes,the results are obtained that,when the magnitude of the selected characteristic earthquake is relatively small,the amplitude of the anomaly before earthquake is different,but when the magnitude is larger,for example MS ≥ 5.0,the impact on the results of this study is very limited.In addition,we briefly discussed the anisotropy of seismic geoelectrical resistivity anomalies and the selection of the characteristic earthquake. 相似文献
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水声信道中信号的时间相关特性是水声微弱信号相关检测的理论基础和具体参数选择依据。文中以厦门港典型的浅海声信道中信号的时间自相关和互相关特性进行实验研究。结果指出,信号有强的时间相关性,无论自相关或互相关性均比海洋环境噪声强得多,因此在水声信道中采用时间相关检测可望达到优良的抗噪声效果。 相似文献
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