Seismic migration can be viewed as either backprojection (diffraction-stack) or backpropagation (wave-field extrapolation) (e.g., Gazdag and Sguazzero, 1984). Migration by backprojection was the view supporting the first digital methods-the diffraction and common tangent stacks of what is now called classical or statistical migration (Lindsey and Hermann. 1970; Rockwell, 1971; Schneider, 1971; ...

In this paper, a novel framework is proposed to enable predictive deployment of unmanned aerial vehicles (UAVs) as temporary base stations (BSs) complement ground cellular systems in face downlink traffic overload. First, learning approach, based on the weighted expectation maximization (WEM) algorithm, estimate user distribution and demand. Next, guarantee truthful information exchange between...

Hamburg (humannews) In der US-Serie „Lie to me“ erkennt Tim Roth, alias Dr. Carl Lightman, mit Hilfe der Wahrnehmungsforschung sofort ob jemand lügt. In der realen Welt geht Managementberaterin Cilly Holle noch einen Schritt weiter: Als Psycho-Physiognomik-Expertin erkennt sie auf den ersten Blick die Stärken und Schwächen ihres Gegenübers, sieht, welche Paare zusammenpassen, wem man wie am bes...

In this paper‎, ‎we prove a multiplicity result for some biharmonic elliptic equation of Kirchhoff type and involving nonlinearities with critical exponential growth at infinity‎. ‎Using some variational arguments and exploiting the symmetries of the problem‎, ‎we establish a multiplicity result giving two nontrivial solutions‎.

Simulation is helpful for evaluating the performances of inspection techniques and requires the modeling of waves scattering from defects. Two classical flaw scattering models have been previously evaluated and implemented in the CIVA platform developed by CEA/LIST to deal with planar defects: the geometrical theory of diffraction (GTD) and the Kirchhoff approximation (KA). These two approaches...

A new approach to seismic migration formalizes the classical diffraction (or common-tangent) stack by relating it to linearized seismic inversion and the generalized Radon transform. This approach recasts migration as the problem of reconstructing the earth’s acoustic scattering potential from its integrals over isochron surfaces. The theory rests on a solution of the wave equation with the geo...

We investigate a pseudo-seismic approach based on the so-called inverse Q-transform as an alternative way of processing transient electromagnetic (TEM) data. This technique transforms the diffusive TEM response into that of propagating waves obeying the standard wave-equation. These transformed data can be input into standard seismic migration schemes with the potential of giving higher resolut...