In this paper, a wavelet sparse representation based beamforming is proposed to improve the resolution and contrast of plane wave emission ultrasound imaging. First, the received signals are described as the convolution of the target scatterers with the point spread function of the system. And then, the wavelet sparse representation model is deduced according to the fact that the target scatter...

Synchronization between the firing times of simultaneously active motor units (MUs) is generally assumed to increase during fatiguing contractions. To date, however, estimates of MU synchronization have relied on indirect measures, derived from surface electromyographic (EMG) interference signals. This study used intramuscular coherence to investigate the correlation between MU discharges in th...

In this paper, using wavelet scalograms and coscalogram of concurrent biomedical signals we were able to detect their short-lived temporal interactions. The complete analysis should include investigation of signal coherence in amplitude and phase. This is achieved with a continuous complex wavelet transform. Thus, in the algorithms developed, we use the Morlet wavelet transform and some measure...

Orthonormal wavelet expansions are applied to atmospheric surface layer velocity measurements. The effect of intermittent events on the energy spectrum of the inertial subrange is investigated through analysis of wavelet coefficients. The local nature of the orthonormal wavelet transform in physical space makes it possible to identify a relationship between the inertial subrange slope of the lo...

The interpretation of SAR images of the sea surface is difficult, due to the complexity of the geophysics and of the interaction mechanisms between electromagnetic and sea waves. The determination of the wind direction is crucial for the evaluation of the wind speed, but its retrieval is still an open issue. One of the few methods able to extract the sea surface wind from SAR data only has been...

Galaxies are arranged in interconnected walls and filaments forming a cosmic web encompassing huge, nearly empty, regions between the structures. Many statistical methods have been proposed in the past in order to describe the galaxy distribution and discriminate the different cosmological models. We present in this paper results relative to the use of new statistical tools using the 3D isotrop...

The paper examines the co-movement relationship between Cryptocurrency and Asian major indices through Wavelet Coherence multiresolution technique Granger causality for result robustness. data of Singapore Japan stock market was used from January 2018 to December 2022, outcome our study shows great co-relationship in movement two listed equity Cryptocurrencies investments. Moreover, that found ...

Changes in the emission rate of volcanic sulphur dioxide (SO2) are crucial parameters for identifying unrest and forecasting eruptive activity. Ground-based ultraviolet (UV) remote sensing provides a near continuous record SO2 rate, with Differential Optical Absorption Spectroscopy (DOAS) being preferred method quantifying absorption from recorded spectra. However, retrieving accurate column am...

Unobtrusive, wearable sensors that measure physiological signals can provide useful information on an individual’s autonomic response. In this paper, we propose techniques to jointly analyze heart rate variations from a group of individuals in order to study group dynamics. We use wavelet coherence to analyze the RR interval signals from a group of N ≥ 2 individuals and uncover shared frequency...

Complex continuous wavelet coherence (WTC) can be used for non-stationary signals, such as electroencephalograms. Areas of the WTC with a coherence higher than the calculated optimal threshold were obtained, and the sum of their areas was used as a criterion to differentiate between groups of experienced insight-focused meditators, calm-focused meditators and a control group. This method demons...