نتایج جستجو برای: wavelet coherence

تعداد نتایج: 109050  

Journal: :E3S web of conferences 2021

The paper presents retrospective analysis of satellite data the upper troposphere / lower stratosphere over epicentral area destructive earthquake M=6.7, occurred in Tien-Shan territory. We established a well-defined temporal and spatial coherence between temperature perturbations seismic activity. used wavelet to identify spectral variations boundary zone before event.

Journal: :Frontiers in Marine Science 2023

In recent years, the populations of many shark species have been depleted drastically around world. present study, we analyzed bycatch in monthly landing data acoupa weakfish ( Cynoscion ) gillnet fisheries state Pará, on northern coast Brazil, between January 1995 and December 2007. Based 4,659 landings, estimated that a total 1,972.50 tons were taken as during study period. The operate Amazon...

2001
Yngvar Larsen Alfred Hanssen Hans L. Pécseli

We present a definition of wavelet-bicoherence based on waveletpolyspectra. We propose a simple estimator for wavelet-bicoherence, and discuss its statistical properties. In particular it is shown that wavelet-bicoherence estimates has a larger number of effective degrees of freedom than traditional Fourier-based bicoherence estimates. The proposed estimator is applied to detection of coherent ...

1989
CHRISTOPHER E. HEIL DAVID F. WALNUT

This paper is an expository survey of results on integral representations and discrete sum expansions of functions in L(R) in terms of coherent states. Two types of coherent states are considered: Weyl–Heisenberg coherent states, which arise from translations and modulations of a single function, and affine coherent states, called “wavelets,” which arise as translations and dilations of a singl...

1999
Jozsef Szilagyi Marc B. Parlange Gabriel G. Katul John D. Albertson

Jozsef Szilagyi*, Marc B. Parlange, Gabriel G. Katul & John D. Albertson Conservation and Survey Division, Institute of Agriculture and Natural Resources, University of Nebraska-Lincoln, 113 Nebraska Hall, Lincoln, NE 68588-0517, USA Department of Geography and Environmental Engineering, The Johns Hopkins University, Baltimore, MD, 21218-2686, USA School of the Environment, Duke University, Dur...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2012
L W Sheppard A Stefanovska P V E McClintock

We present a method for the testing of significance when evaluating the coherence of two oscillatory time series that may have variable amplitude and frequency. It is based on evaluating the self-correlations of the time series. We demonstrate our approach by the application of wavelet-based coherence measures to artificial and physiological examples. Because coherence measures of this kind are...

Journal: :Complexity 2021

This paper employed wavelet coherence and partial to investigate the time-frequency effect of global economic policy uncertainty on comovement five agricultural commodities such as maize, oat, rice, soybean, wheat using monthly data from January 1997 December 2019. In general, we observed heterogeneity in structures market at different scales which are profound high frequencies bivariate cohere...

2000
Ta-Hsin Li William R. Klemm

It is hypothesized that the perception of an alternative image in ambiguous figures would be manifested as an increase in synchronization of EEG signals over multiple scalp sites as “cognitive binding” occurs. A statistical timefrequency analysis (STFA) approach is taken to detect cognitive binding. The STFA approach consists of an analysis filter bank that extracts useful components from the i...

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