نتایج جستجو برای: scalogram

تعداد نتایج: 175  

2003
Myong K. Jeong Di Chen Jye-Chyi Lu

Scalograms provide measures of signal energy at various frequency bands and are commonly used in decision making in many fields including signal and image processing, astronomy and metrology. This article extends the scalogram’s ability for handling noisy and possibly massive data. The proposed thresholded scalogram is built on the fast wavelet transform, which can capture non-stationary change...

2006
Engin AVCI Ibrahim TURKOGLU Mustafa POYRAZ

In this study, a Mexican Hat Wavelet scalogram neural genetic network approach is proposed for signal classification. The Wavelet Scalogram network uses a Levenberg-Marquardt multilayer feedforward neural network-genetic algorithm hybrid structure, and its input layer constitutes the feature extraction part, whereas the hidden layer and output layer constitute the signal classification part. Fr...

2013
Imen Jemaa Kais Ouni Yves Laprie Slim Ouni Jean-Paul Haton Kaïs Ouni

In this paper we present a new formant tracking algorithm where the formant frequencies estimation was based on local maxima detection of a time frequency representation. This representation can be shown by a scalogram issued from a complex wavelet transform. The formant frequency candidates are validated as local maxima of scalogram which correspond to wavelet ridges. Then in the proposed algo...

2007
F. ROUEFF M. S. TAQQU

We consider linear processes, not necessarily Gaussian, with long, short or negative memory. The memory parameter is estimated semi-parametrically using wavelets from a sample X1, . . . , Xn of the process. We treat both the log-regression wavelet estimator and the wavelet Whittle estimator. We show that these estimators are asymptotically normal as the sample size n → ∞ and we obtain an explic...

2007
S. Su Ruxu Du

This paper presents a new method for the signature analysis of mechanical watch movements. Contrary to the existing method, it analyzes the time-frequency features of mechanical watch movement through a combination of reassigned scalogram and Finite Element Analysis (FEA). By mapping the signal into a 2D domain of time and frequency, the reassigned scalogram reveals the frequency components of ...

Journal: :BioMedical Engineering OnLine 2004
Oliver Faust Rajendra Acharya U SM Krishnan Lim Choo Min

BACKGROUND Analysis of heart rate variation (HRV) has become a popular noninvasive tool for assessing the activities of the autonomic nervous system (ANS). HRV analysis is based on the concept that fast fluctuations may specifically reflect changes of sympathetic and vagal activity. It shows that the structure generating the signal is not simply linear, but also involves nonlinear contributions...

2016
Stephanie A. Schuckers Daniel L. Stevens

Low probability of intercept radar signals, which are often problematic to detect and characterize, have as their goal ‘to see and not be seen’. Digital intercept receivers are currently moving away from Fourier-based analysis and towards classical time-frequency analysis techniques for the purpose of analyzing these low probability of intercept radar signals. This paper presents the novel appr...

Journal: :iranian journal of public health 0
m bahadori l shams j sadeghifar p hamouzadeh m nejati

background: one of the main and basic pillars of health system promotion is the equitable distribution of health facilities in order to ensure fair access of people in the community to the health services. the goal of this study was to classify the health structural indicators in golestan province using scalogram analysis model. method: a descriptive study was conducted in 2010. data related to...

2014
Marianne Clausel François Roueff Murad Taqqu

Consider a non–linear function G(Xt) where Xt is a stationary Gaussian sequence with long–range dependence. The usual reduction principle states that the partial sums of G(Xt) behave asymptotically like the partial sums of the first term in the expansion of G in Hermite polynomials. In the context of the wavelet estimation of the long–range dependence parameter, one replaces the partial sums of...

Journal: :Int. J. Applied Earth Observation and Geoinformation 2014
Bingwen Qiu Ming Zhong Zhenghong Tang Chongyang Wang

Cropping intensity is one of the major factors in crop production and agricultural intensification. A new double-cropping croplands mapping methodology using Moderate Resolution Imaging Spectroradiometer (MODIS) time series datasets through continuous wavelet transform was proposed in this study. This methodology involved four steps. First, daily continuous MODIS Enhanced Vegetation Index (EVI)...

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