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Decomposition in blocks at the level of wavelet coefficients and T(1 ) theorem on Hardy space
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作者 杨奇祥 《Journal of Zhejiang University Science》 CSCD 2002年第1期94-99,共6页
This paper deals with the establishment of \%T(1)\% theorem on Hardy space \%H 1\% under condition of weak regularity. An operator or a function is identified on the basis of their wavelet coefficients which are regr... This paper deals with the establishment of \%T(1)\% theorem on Hardy space \%H 1\% under condition of weak regularity. An operator or a function is identified on the basis of their wavelet coefficients which are regrouped on some blocks. The actions of each block operator (pseudo\|annular operator) on each block function (atom) are exactly analyzed to establish \%T(1)\% theorem on Hardy space. 展开更多
关键词 hardy space wavelet coefficients BLOCKS
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Quantitative Diagnosis of Fault Severity Trend of Rolling Element Bearings 被引量:6
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作者 CUI Lingli MA Chunqing +1 位作者 ZHANG Feibin WANG Huaqing 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第6期1254-1260,共7页
The condition monitoring and fault diagnosis of rolling element bearings are particularly crucial in rotating mechanical applications in industry. A bearing fault signal contains information not only about fault condi... The condition monitoring and fault diagnosis of rolling element bearings are particularly crucial in rotating mechanical applications in industry. A bearing fault signal contains information not only about fault condition and fault type but also the severity of the fault. This means fault severity quantitative analysis is one of most active and valid ways to realize proper maintenance decision. Aiming at the deficiency of the research in bearing single point pitting fault quantitative diagnosis, a new back-propagation neural network method based on wavelet packet decomposition coefficient entropy is proposed. The three levels of wavelet packet coefficient entropy(WPCE) is introduced as a characteristic input vector to the BPNN. Compared with the wavelet packet decomposition energy ratio input vector, WPCE shows more sensitive in distinguishing from the different fault severity degree of the measured signal. The engineering application results show that the quantitative trend fault diagnosis is realized in the different fault degree of the single point bearing pitting fault. The breakthrough attempt from quantitative to qualitative on the pattern recognition of rolling element bearings fault diagnosis is realized. 展开更多
关键词 rolling bearing fault quantitative analysis back-propagation neural network wavelet packet coefficient entropy wavelet packet energy ratio
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Development of Instrument Control System Using Biosignals Created by the Change of Eyes Movement Sequence
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作者 肖云翔 李刚 NOGATA Fumio 《Transactions of Tianjin University》 EI CAS 2003年第2期115-118,共4页
A new biosi gn al control system that offers the disables the opportunities to control electric appliances is proposed.The four types of signals created by the eyes movements in four directions(up,down,left,and right)... A new biosi gn al control system that offers the disables the opportunities to control electric appliances is proposed.The four types of signals created by the eyes movements in four directions(up,down,left,and right),which are taken as four basic signals , are detected at the forehead.Permutation of 2 signals out of them creates 16 d ifferent signals.Permutation of 3 signals out of them creates 64 signals.They al l amounts to 84 control signals.They are thought to be applicable for the operat ion of some instruments.Furthermore,the dynamic biosignals created by the slow e yes movement is speculated to be applicable for the more convenient control of t hem. 展开更多
关键词 eyes movement biosignal control brai n wave visual angle Fast Fourier Transform wavelet coefficient
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TESTING FOR OUTLIERS IN TIME SERIES USING WAVELETS 被引量:1
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作者 ZHANGTong ZHANGXibin ZHANGShiying 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2003年第4期453-465,共13页
One remarkable feature of wavelet decomposition is that the waveletcoefficients are localized, and any singularity in the input signals can only affect the waveletcoefficients at the point near the singularity. The lo... One remarkable feature of wavelet decomposition is that the waveletcoefficients are localized, and any singularity in the input signals can only affect the waveletcoefficients at the point near the singularity. The localized property of the wavelet coefficientsallows us to identify the singularities in the input signals by studying the wavelet coefficients atdifferent resolution levels. This paper considers wavelet-based approaches for the detection ofoutliers in time series. Outliers are high-frequency phenomena which are associated with the waveletcoefficients with large absolute values at different resolution levels. On the basis of thefirst-level wavelet coefficients, this paper presents a diagnostic to identify outliers in a timeseries. Under the null hypothesis that there is no outlier, the proposed diagnostic is distributedas a χ_1~2. Empirical examples are presented to demonstrate the application of the proposeddiagnostic. 展开更多
关键词 OUTLIER wavelet decomposition wavelet coefficients
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Transient Mould Friction Based on the Wavelet Theory
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作者 Yong MA Cheng PENG +1 位作者 Wei GUI Fang-yin WANG 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2015年第9期785-794,共10页
The mould friction is an important parameter reflecting the initial shell and mould lubrication conditions.The research of mould friction is very important to the optimization and developing of continuous casting.The ... The mould friction is an important parameter reflecting the initial shell and mould lubrication conditions.The research of mould friction is very important to the optimization and developing of continuous casting.The measured mould friction under hydraulic oscillation mode was researched with wavelet analysis to reveal its time-frequency characteristics.Firstly,the mould friction signals under different production conditions were monitored and the mould friction was calculated.Then,mother wavelet function was selected from three wavelet functions which were chosen preliminary according to the characteristics of mould friction and wavelet theory.Through wavelet transformation,mould friction signal was projected onto the wavelet domain,and the time-frequency characteristics of mould friction under different production conditions were obtained and discussed.Mould friction under different production conditions such as different oscillation mode,casting speed fluctuation,increasing and decreasing stage of casting speed and breakout occurrence was reported in detail in the wavelet time-frequency maps.The characteristics of mould friction were reflected well through wavelet transformation which proved that wavelet analysis had a good feasibility for mould friction study and can further reveal the nature of mould friction. 展开更多
关键词 mould friction hydraulic oscillator time-frequency wavelet transform coefficient wavelet
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A robust object tracking framework based on a reliable point assignment algorithm 被引量:2
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作者 Rong-feng ZHANG Ting DENG +2 位作者 Gui-hong WANG Jing-lun SHI Quan-sheng GUAN 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2017年第4期545-558,共14页
Visual tracking, which has been widely used in many vision fields, has been one of the most active research topics in computer vision in recent years. However, there are still challenges in visual tracking, such as il... Visual tracking, which has been widely used in many vision fields, has been one of the most active research topics in computer vision in recent years. However, there are still challenges in visual tracking, such as illumination change, object occlu- sion, and appearance deformation. To overcome these difficulties, a reliable point assignment (RPA) algorithm based on wavelet transform is proposed. The reliable points are obtained by searching the location that holds local maximal wavelet coefficients. Since the local maximal wavelet coefficients indicate high variation in the image, the reliable points are robust against image noise, illumination change, and appearance deformation. Moreover, a Kalman filter is applied to the detection step to speed up the detection processing and reduce false detection. Finally, the proposed RPA is integrated into the tracking-learning-detection (TLD) framework with the Kalman filter, which not only improves the tracking precision, but also reduces the false detections. Experimental results showed that the new framework outperforms TLD and kernelized correlation filters with respect to precision, f-measure, and average overlap in percent. 展开更多
关键词 Local maximal wavelet coefficients Reliable point assignment Object tracking Tracking learning detection (TLD) Kalman filter
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