※ 계산수학 세미나 ※

연사 : 하 태 영 박사 (국가수리과학연구소)
일시 : 2008.5.9 (금) 오후 4:30
장소 : 산업경영학동 3221호
제목 : Seismic waveform inversion via backpropagation
         algorithm and its applications

내용 : During the last decades, finding the structure of subsurface has been tackled by applied mathematicians and geophysicists with an increasing degree of success, who has mainly handled by traveltime tomography or waveform inversion.
Since Tarantola(1984) developed the waveform inversion by the self-adjoint state of wave equation, many people have developed the algorithm of computing the steepest descent direction of each object function by exploiting a matrix formulation coming from finite element or difference method.

And, to obtain the inversion of large sized computation domain, we need the parallel algorithms. To parallelize the seismic waveform technique, many people have handled the frequency domain modeling.
An essential advantage of the space-frequency domain formulation is that in order to compute the solution at the current time it does not require the use of the time history of the system which is necessary and expensive in the classical space-time  approach. Furthermore, each temporal frequency problem can be solved independently of the other frequencies, which yields a naturally parallelizable scheme by distributing the frequencies across the computational processors. Moreover, back-propagation algorithm in parallel algorithm according to frequencies can be used. In this talk, I give theory of seismic waveform inversions using backpropagation techniques and its various application, DC and MT inversion.