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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Filtro kl/dvs para atenua??o do ru?do "ground roll" / Filtro kl/dvs para atenua??o do ru?do "ground roll"

Figueiredo, Pedro Henrique C?ceres 07 August 2010 (has links)
Made available in DSpace on 2014-12-17T14:08:40Z (GMT). No. of bitstreams: 1 PedroHCF_DISSERT.pdf: 3177377 bytes, checksum: aee262ba866eb8f7862d4fdf2b03cfdf (MD5) Previous issue date: 2010-08-07 / In geophysics there are several steps in the study of the Earth, one of them is the processing of seismic records. These records are obtained through observations made on the earth surface and are useful for information about the structure and composition of the inaccessible parts in great depths. Most of the tools and techniques developed for such studies has been applied in academic projects. The big problem is that the seismic processing power unwanted, recorded by receivers that do not bring any kind of information related to the reflectors can mask the information and/or generate erroneous information from the subsurface. This energy is known as unwanted seismic noise. To reduce the noise and improve a signal indicating a reflection, without losing desirable signals is sometimes a problem of difficult solution. The project aims to get rid of the ground roll noise, which shows a pattern characterized by low frequency, low rate of decay, low velocity and high amplituds. The Karhunen-Lo?ve Transform is a great tool for identification of patterns based on the eigenvalues and eigenvectors. Together with the Karhunen-Lo?ve Transform we will be using the Singular Value Decomposition, since it is a great mathematical technique for manipulating data / Na geof?sica existem diversas etapas no estudo da Terra, uma delas ? o processamento de registros s?smicos. Esses registros s?o obtidos atrav?s de observa??es realizadas na superf?cie, sendo ?teis para informa??es sobre a estrutura e a composi??o das zonas inacess?veis em grandes profundidades. Grande parte das ferramentas e t?cnicas desenvolvidas para tais estudos tem sido aplicada em pesquisas acad?micas. O grande problema do processamento s?smico ? a energia indesejada, registrada pelos receptores que n?o trazem nenhum tipo de informa??o em rela??o aos refletores podendo mascarar as informa??es e/ou gerar informa??es erradas da subsuperf?cie. Essa energia indesejada ? conhecida como ru?do s?smico. Atenuar esse ru?do para melhorar um sinal que indica uma reflex?o, sem perder sinal desej?vel ? algumas vezes um problema de dif?cil solu??o. O projeto tem como objetivo a atenua??o do ru?do ground roll , o qual apresenta um padr?o caracterizado pela baixa freq??ncia, baixa velocidade de propaga??o e forte amplitude. A Transformada de Karhunen-Lo?ve ? uma ?tima ferramenta para identifica??o de padr?es baseada nos autovalores e autovetores. Em conjunto com a Transformada de Karhunen-Lo?ve ser? utilizado a Decomposi??o em Valores Singulares, j? que a mesma ? uma ?tima t?cnica matem?tica para manipula??o dos dados

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