We propose the use of a new implementation of the hyperanalytic wavelet transform, (HWT), in association with a Maximum a Posteriori (MAP) filter named bishrink. The denoising methods based on wavelets are sensitive to the selection of the mother wavelets. Taking into account the drawbacks of the bishrink filter and the sensitivity with the selection of the mother wavelets we propose a denoisin...

Abstrac t This paper presents a method for locating and measuring the size of cracks in beams by time of flight (ToF) of ultrasonic wave. The echo detected was processed using the stationary wavelet transform and the Hilbert transform. The accuracy of the information obtained from the processed signal depends on the selected mother wavelet. To select the best mother wavelet for signal processin...

This paper deals with two popular and powerful methods in noise and harmonic detection field of digital signal processing. The first one is the Windowing technique and the other one is wavelet transform. The proposed method uses these methods in the traditional synchronous fundamental dqframe algorithm. In other words, a windowing-wavelet based method is formed as a low pass filter. The Hamming...

In this paper a method for extracting Partial Discharge (PD) signals is introduced, which is implemented for evaluating electrical measured partial discharges on a 66 kV / 25 MVA fully interleaved winding of a power transformer. Applying wavelet transform to a signal produces a wavelet detail coefficient distribution throughout the time-scale, which depends on the mother wavelet chosen. This me...

Mammographic images are used for detection of breast cancer in women. In this paper denoising algorithms for mammographic images in wavelet domain are considered. A modified approach for denoising of mammographic images using Diversity Enhanced Wavelet Transform has been proposed. Diversity of the Wavelet Transform is enhanced by taking different mother wavelets and different number of levels t...

Introduction: Crackles are discontinuous, non-stationary respiratory sounds and can be characterized by their duration and frequency. In the literature, many techniques of filtering, feature extraction, and classification were presented. Although the discrete wavelet transform (DWT) is a well-known tool in this area, issues like signal border extension, mother-wavelet selection, and its subband...

Na(+) and K(+) channel-blocking drugs have anti- and proarrhythmic effects. Their effects during fibrillation, however, remain poorly understood. We used computer simulation of a two-dimensional (2-D) structurally normal tissue model with phase I of the Luo-Rudy action potential model to study the effects of Na(+) and K(+) channel blockade on vulnerability to and termination of reentry in simul...

The identification of dynamic parameters is of prime importance in vibration analysis. A number of different time and frequency domain methods have been developed for vibration analysis of time-invariant systems. However, many engineering systems exhibit timevariant behavior. This paper presents a simulation example of a time-variant approach used for parameter identification in a simple vibrat...

Human gait is a complex interaction of many nonlinear systems and stride intervals exhibiting self-similarity over long time scales that can be modeled as a fractal process. The scaling exponent represents the fractal degree and can be interpreted as a "biomarker" of relative diseases. The previous study showed that the average wavelet method provides the most accurate results to estimate this ...

Sudden cardiac death is one of the major causes of death in the industrialized world. It is most often caused by a cardiac arrhythmia called ventricular fibrillation (VF). Despite its large social and economical impact, the mechanisms for VF in the human heart yet remain to be identified. Two of the most frequently discussed mechanisms observed in experiments with animal hearts are the multiple...