Branch/mode competition in the flow-induced vibration of a square cylinder

The flow-induced vibration response of a square cross-sectional cylinder with low mass and damping ratio is analysed using continuous wavelet transforms (CWT) for three representative angles of attack of the cylinder to the incoming flow. The amplitude and frequency responses over a range of flow velocities map out multiple regimes (branches) of oscillation. Analysis of the time–frequency domain for boundary regions between branches using CWT reveals intermittency at the synchronization region boundaries as well as mode competition at branch boundaries. Complementary recurrence analysis shows that periodic dynamical states are interrupted by chaotic bursts in the transition regions around the higher branch at an angle of attack of α = 20° (a new branch first observed by Nemes et al. (2012 J. Fluid Mech. 710 , 102–130 ( doi:10.1017/jfm.2012.353 ))), supporting the CWT-based frequency–time analysis. This article is part of the theme issue ‘Redundancy rules: the continuous wavelet transform comes of age’.

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Quantitative feature analysis of continuous analytic wavelet transforms of electrocardiography and electromyography

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2017.0250 ◽

2018 ◽

Vol 376 (2126) ◽

pp. 20170250 ◽

Cited By ~ 3

Author(s):

Mark P. Wachowiak ◽

Renata Wachowiak-Smolíková ◽

Michel J. Johnson ◽

Dean C. Hay ◽

Kevin E. Power ◽

...

Keyword(s):

Wavelet Transform ◽

Continuous Wavelet Transform ◽

Wavelet Transforms ◽

Continuous Wavelet ◽

Theme Issue ◽

Practical Applications ◽

Time Frequency ◽

New Family ◽

Physiological Processes ◽

Analytic Wavelet

Theoretical and practical advances in time–frequency analysis, in general, and the continuous wavelet transform (CWT), in particular, have increased over the last two decades. Although the Morlet wavelet has been the default choice for wavelet analysis, a new family of analytic wavelets, known as generalized Morse wavelets, which subsume several other analytic wavelet families, have been increasingly employed due to their time and frequency localization benefits and their utility in isolating and extracting quantifiable features in the time–frequency domain. The current paper describes two practical applications of analysing the features obtained from the generalized Morse CWT: (i) electromyography, for isolating important features in muscle bursts during skating, and (ii) electrocardiography, for assessing heart rate variability, which is represented as the ridge of the main transform frequency band. These features are subsequently quantified to facilitate exploration of the underlying physiological processes from which the signals were generated. This article is part of the theme issue ‘Redundancy rules: the continuous wavelet transform comes of age’.

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COMPLEMENTARY ANALYSIS TO HEART SOUNDS WHILE USING THE SHORT TIME FOURIER AND THE CONTINUOUS WAVELET TRANSFORMS

Biomedical Engineering Applications Basis and Communications ◽

10.4015/s1016237207000434 ◽

2007 ◽

Vol 19 (05) ◽

pp. 331-339

Author(s):

S. M. Debbal ◽

F. Bereksi-Reguig

Keyword(s):

Fourier Transform ◽

Wavelet Transform ◽

Continuous Wavelet Transform ◽

Wavelet Transforms ◽

Continuous Wavelet ◽

Short Time Fourier Transform ◽

Continuous Wavelet Transforms ◽

Time Frequency ◽

Quantitative Measurements ◽

Short Time

This paper presents the analysis and comparisons of the short time Fourier transform (STFT) and the continuous wavelet transform techniques (CWT) to the four sounds analysis (S1, S2, S3 and S4). It is found that the spectrogram short-time Fourier transform (STFT), cannot perfectly detect the internals components of these sounds that the continuous wavelet transform. However, the short time Fourier transform can provide correctly the extent of time and frequency of these four sounds. Thus, the STFT and the CWT techniques provide more features and characteristics of the sounds that will hemp physicians to obtain qualitative and quantitative measurements of the time-frequency characteristics.

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Spectral decomposition using time-frequency continuous wavelet transforms for fault detection in the Bakken Formation

10.1190/segam2017-17670965.1 ◽

2017 ◽

Author(s):

Ismot Jahan ◽

John Castagna

Keyword(s):

Fault Detection ◽

Spectral Decomposition ◽

Wavelet Transforms ◽

Continuous Wavelet ◽

Bakken Formation ◽

Continuous Wavelet Transforms ◽

Time Frequency

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Applications and Comparison of Continuous Wavelet Transforms on Analysis of A-wave Impulse Noise

Archives of Acoustics ◽

10.1515/aoa-2015-0050 ◽

2015 ◽

Vol 40 (4) ◽

pp. 503-512 ◽

Cited By ~ 2

Author(s):

Jun Qin ◽

Pengfei Sun

Keyword(s):

Hearing Loss ◽

Wavelet Transform ◽

Wavelet Transforms ◽

Impulse Noise ◽

Continuous Wavelet ◽

Continuous Wavelet Transforms ◽

Time Frequency ◽

Mexican Hat ◽

Meyer Wavelets ◽

Hazard Level

Abstract Noise induced hearing loss (NIHL) is a serious occupational related health problem worldwide. The A-wave impulse noise could cause severe hearing loss, and characteristics of such kind of impulse noise in the joint time-frequency (T-F) domain are critical for evaluation of auditory hazard level. This study focuses on the analysis of A-wave impulse noise in the T-F domain using continual wavelet transforms. Three different wavelets, referring to Morlet, Mexican hat, and Meyer wavelets, were investigated and compared based on theoretical analysis and applications to experimental generated A-wave impulse noise signals. The underlying theory of continuous wavelet transform was given and the temporal and spectral resolutions were theoretically analyzed. The main results showed that the Mexican hat wavelet demonstrated significant advantages over the Morlet and Meyer wavelets for the characterization and analysis of the A-wave impulse noise. The results of this study provide useful information for applying wavelet transform on signal processing of the A-wave impulse noise.

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Time-Frequency Analysis of Shock and Vibration Measurements Using Wavelet Transforms

International Journal of Advanced Packaging Technology ◽

10.23953/cloud.ijapt.15 ◽

2014 ◽

Vol 2 (1) ◽

pp. 60-69

Author(s):

Divya Choudhary ◽

◽

Siripong Malasri ◽

Mallory Harvey ◽

Amanda Smith

Keyword(s):

Frequency Analysis ◽

Wavelet Transforms ◽

Vibration Measurements ◽

Time Frequency Analysis ◽

Time Frequency

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Impacts of Sample Preparation Methodology on TEM Failure Analysis of Advanced Semiconductor Devices

ISTFA 2011: Conference Proceedings from the 37th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2011p0301 ◽

2011 ◽

Author(s):

Yongkai Zhou ◽

Jie Zhu ◽

Han Wei Teo ◽

ACT Quah ◽

Lei Zhu ◽

...

Keyword(s):

Sample Preparation ◽

Failure Analysis ◽

Case Studies ◽

Thickness Measurement ◽

Interface Roughness ◽

Silicide Formation ◽

Cross Sectional ◽

Inspection Method ◽

Low Mass

Abstract In this paper, two failure analysis case studies are presented to demonstrate the importance of sample preparation procedures to successful failure analyses. Case study 1 establishes that Palladium (Pd) cannot be used as pre-FIB coating for SiO2 thickness measurement due to the spontaneously Pd silicide formation at the SiO2/Si interface. Platinum (Pt) is thus recommended, in spite of the Pt/SiO2 interface roughness, as the pre-FIB coating in this application. In the second case study, the dual-directional TEM inspection method is applied to characterize the profile of the “invisible” tungsten residue defect. The tungsten residue appears invisible in the planeview specimen due to the low mass-thickness contrast. It is then revealed in the cross-sectional TEM inspection.

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Sugar-Sweetened Beverages Consumption and Associated Factors among Northeastern Chinese Children

Nutrients ◽

10.3390/nu13072233 ◽

2021 ◽

Vol 13 (7) ◽

pp. 2233

Author(s):

Xuxiu Zhuang ◽

Yang Liu ◽

Joel Gittelsohn ◽

Emma Lewis ◽

Shenzhi Song ◽

...

Keyword(s):

Normal Weight ◽

Chinese Children ◽

Sugar Sweetened Beverages ◽

Related Factors ◽

Cross Sectional ◽

Time Frequency ◽

Sweetened Beverages ◽

Convenience Stores ◽

Pocket Money ◽

At Home

(1) Background: The present study aimed to investigate the association between home-related factors, community environmental factors, and sugar-sweetened beverages (SSBs) intake among Northeastern Chinese children. (2) Methods: Cross-sectional. Children with complete data were included in the analysis (n = 901). A questionnaire modified according to BEVQ-15 measured the intake of SSBs. Logistic regression was applied to determine the factors associated with the consumption of SSBs. IBM SPSS Statistics 23.0 was applied to perform all statistical analyses. (3) Results: The mean total amount of SSBs consumed on a weekly basis was 2214.04 ± 2188.62 mL. Children’s weekly pocket money, frequency of SSBs purchase, SSBs availability at home, the number of accessible supermarkets, and frequency of weekly visits to convenience stores were all found to be associated with a high intake of SSBs among all children. Among children of normal weight, the findings indicated that weekly pocket money, SSBs availability at home, and number of accessible supermarkets were associated with a high SSBs intake. At the same time, frequency of SSBs purchase, mother’s SSBs intake, and frequency of weekly visits to convenience stores were associated with a high SSBs intake among children with obesity. (4) Conclusions: Given the potential negative health effects of high SSBs intake, it is crucial to pay attention to home-related factors and community environment.

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Interpolation in wavelet spaces and the HRT-conjecture

Journal of Pseudo-Differential Operators and Applications ◽

10.1007/s11868-021-00386-y ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Eirik Berge

Keyword(s):

Compact Group ◽

Wavelet Transforms ◽

Reproducing Kernel ◽

Reproducing Kernel Hilbert Space ◽

Space Structure ◽

Locally Compact Group ◽

Locally Compact ◽

Positive Type ◽

Time Frequency ◽

Hrt Conjecture

AbstractWe investigate the wavelet spaces $$\mathcal {W}_{g}(\mathcal {H}_{\pi })\subset L^{2}(G)$$ W g ( H π ) ⊂ L 2 ( G ) arising from square integrable representations $$\pi :G \rightarrow \mathcal {U}(\mathcal {H}_{\pi })$$ π : G → U ( H π ) of a locally compact group G. We show that the wavelet spaces are rigid in the sense that non-trivial intersection between them imposes strong restrictions. Moreover, we use this to derive consequences for wavelet transforms related to convexity and functions of positive type. Motivated by the reproducing kernel Hilbert space structure of wavelet spaces we examine an interpolation problem. In the setting of time–frequency analysis, this problem turns out to be equivalent to the HRT-conjecture. Finally, we consider the problem of whether all the wavelet spaces $$\mathcal {W}_{g}(\mathcal {H}_{\pi })$$ W g ( H π ) of a locally compact group G collectively exhaust the ambient space $$L^{2}(G)$$ L 2 ( G ) . We show that the answer is affirmative for compact groups, while negative for the reduced Heisenberg group.

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