doctoralThesis
Representações espectrais de sistemas complexos: aplicações à síntese de superfícies brownianas fracionárias anisotrópicas, filtragem de sinais e identificação de correlações
Fecha
2012-08-24Registro en:
HENRIQUES, Marcos Vinícius Cândido. Representações espectrais de sistemas complexos:
aplicações à síntese de superfícies brownianas
fracionárias anisotrópicas, filtragem de sinais e
identificação de correlações. 2012. 110 f. Tese (Doutorado em Física da Matéria Condensada; Astrofísica e Cosmologia; Física da Ionosfera) - Universidade Federal do Rio Grande do Norte, Natal, 2012.
Autor
Henriques, Marcos Vinícius Cândido
Resumen
In this thesis, we study the application of spectral representations to the solution of problems
in seismic exploration, the synthesis of fractal surfaces and the identification of correlations
between one-dimensional signals. We apply a new approach, called Wavelet Coherency, to
the study of stratigraphic correlation in well log signals, as an attempt to identify layers
from the same geological formation, showing that the representation in wavelet space, with
introduction of scale domain, can facilitate the process of comparing patterns in geophysical
signals. We have introduced a new model for the generation of anisotropic fractional
brownian surfaces based on curvelet transform, a new multiscale tool which can be seen as
a generalization of the wavelet transform to include the direction component in multidimensional
spaces. We have tested our model with a modified version of the Directional Average
Method (DAM) to evaluate the anisotropy of fractional brownian surfaces. We also used the
directional behavior of the curvelets to attack an important problem in seismic exploration:
the atenuation of the ground roll, present in seismograms as a result of surface Rayleigh
waves. The techniques employed are effective, leading to sparse representation of the signals,
and, consequently, to good resolutions