نتایج جستجو برای: migration operator

تعداد نتایج: 234293  

Journal: :Applied Mathematics and Computation 2005
João Luiz Martins

Two important tools in seismic processing––Kirchhoff migration and demigration operators––are the basis for many imaging problems solution. Due to high numerical and computational requirements, the use of those tools for three dimensions are very computation-costly. This fact has motivated us to investigate Kirchhoff migration operations for simpler types of media in order to provide faster res...

Biogeography-Based Optimization (BBO) algorithm has recently been of great interest to researchers for simplicity of implementation, efficiency, and the low number of parameters. The BBO Algorithm in optimization problems is one of the new algorithms which have been developed based on the biogeography concept. This algorithm uses the idea of animal migration to find suitable habitats for solvin...

2010
Markus Herrmannsdoerfer Sander Vermolen Guido Wachsmuth

Modeling languages and thus their metamodels are subject to change. When a metamodel is evolved, existing models may no longer conform to it. Manual migration of these models in response to metamodel evolution is tedious and error-prone. To significantly automate model migration, operator-based approaches provide reusable coupled operators that encapsulate both metamodel evolution and model mig...

Journal: :Appl. Soft Comput. 2016
Xu Chen Huaglory Tianfield Wenli Du Guohai Liu

Biogeography-based optimization (BBO) is a new evolutionary algorithm. The major problem of basic BBO is that its migration operator is rotationally variant, which leaves BBO performing poorly in non-separable problems. To overcome this drawback of BBO, in this paper, we propose the covariance matrix based migration (CMM) to relieve BBO’s dependence upon the coordinate system so that BBO’s rota...

2001
Zhiming Li

One-pass three-dimensional (3-D) depth migration potentially offers more accurate imaging results than does conventional two-pass 3-D migration for variable velocity media. Conventional one-pass 3-D migration, using the method of finite-difference inline and crossline splitting, however, creates large errors in the image of complex structures. These errors are due to paraxial wave-equation appr...

1998
Jing Chen

Application of least-squares Kirchhoff migration (LSM) to synthetic reverse vertical seismic profile data (RVSP) demonstrates that LSM reduces the migration artifacts, improves the image resolution and produces a more accurate image than the standard migration, but cannot completely recover the model reflectivity for AVO analysis because of the limited data coverage. The influence of incomplete...

2000
Paul Sava

This tutorial describes mixed-domain wave-equation migration and migration velocity analysis techniques in a unified theoretical framework. I review two of the most general mixed-domain migration methods, Fourier finite-difference and generalized screen, and show how other commonly used wave-equation migration methods come about as special cases. I use the Born approximation to derive general e...

2017
Daniel Rocha Paul Sava Antoine Guitton

We have developed a least-squares reverse time migration (LSRTM) method that uses an energy-based imaging condition to obtain faster convergence rates when compared with similar methods based on conventional imaging conditions. To achieve our goal, we also define a linearized modeling operator that is the proper adjoint of the energy migration operator. Our modeling and migration operators use ...

2002
Gerard T. Schuster

The standard reverse-time migration (RTM) algorithm is usually described as zero-lag correlation of the backprojected data with the source wavefield. The data are back-projected by a finite-difference algorithm, where each trace acts as a source-time history of a point source at the geophone location. This is a simple and easily understood migration method, but appears inflexible to improvement...

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