Reverse-time de-migration (RTDM) is formulated as the adjoint operator of reverse-time migration (RTM). In acoustic medium, RTM provides a good approximation to the inverse of RTDM, and can be used to iteratively invert for the reflectivity image in least-squares RTM (LSRTM). In viscoelastic medium, however, the adjoint of the RTDM operator is far from its inverse because of amplitude attenuati...

In the original speciication of the Ecolab model, spatial variation of the system's variables was included, with an additional migration operator introduced proportional to the divergence of the species density. Suitably discretized, the model then consists of a number of cells, each running the non-spatial Ecolab model, linked together by the migration operator. This paper reports on the imple...

Spatial aliasing in multichannel seismic data can be overcome by solving an inversion in which the model is the section that would be recorded in a well sampled zero-offset experiment, and the data are seismic data after normal moveout (NMO). The formulation of the (linear) relation between the data and the model is based on the wave equation and on Fourier analysis of aliasing. A processing se...

Reverse time migration produces an image by crosscorrelating the solution of the wave equation solved forward in time with the wave equation solved backwards in time. Solution of the wave equation can be computationally prohibitive for large subsurface regions. Therefore one typically combines a finite difference discretization of the wave equation with a parallel computing paradigm such as dom...

This paper presents a distributed genetic algorithm for the discovery of classification rules. Population is contained in the form of interconnected demes. The local selection and reproduction mechanism is used to evolve the species within demes, and diversity is enhanced by migrating rules among some of the selected demes. Subsumption operator has been finally applied to reduce the complexity ...

The traditional compressed sensing SFCWSAR (Stepped Frequency Continuous Wave Synthetic Aperture Radar) sparse reconstruction algorithm consumes a lot of computer memory and cannot compensate the range migration in same pulse group. Based on this, this paper proposes based an approximate observation operator. First, replaces accurate operator with operator, which greatly reduces consumption whi...

Wave-equation migration velocity analysis is based on the linear relation that can be established between a perturbation in the migrated image and the corresponding perturbation in the slowness function. Our method formulates an objective function in the image space, in contrast with other wave-equation tomography techniques which formulate objective functions in the data space. We iteratively ...

Biogeography Based Optimization (BBO) is a recently introduced optimization technique based on science of biogeography, i. e. , study of distribution of biological species over space and time. In BBO, potential solutions of a problem are grouped in integer vectors known as habitats. Feature, i. e. , Suitability Index Variable (SIV), sharing among various habitats is made to occur with migration...