BEGIN:VCALENDAR VERSION:2.0 PRODID:-//DTU.dk//NONSGML DTU.dk//EN CALSCALE:GREGORIAN BEGIN:VEVENT DTSTART:20160929T140000 DTEND:20160929T150000 SUMMARY:DCAMM Seminar - Full-waveform inversion for three-dimensional site characterization DESCRIPTION:

A DCAMM seminar will be presented by

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Professor Loukas Kallivokas

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The University of Texas at Austin, USA

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\n\n 

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Abstract: 
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We discuss the development of a full-waveform-inversion-based methodology for the imaging of near-surface formations using sparse    data. Specifically, we address the imaging of arbitrarily heterogeneous sites in three dimensions, using elastic waves as probing agents      and the response of the site recorded at sparsely distributed surface sensors.
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\nWe cast the associated inverse medium problem directly in the time domain and use PDE-constrained optimization ideas to obtain the   profile of the probed site in terms of the spatially-distributed Lamé parameters (or the P- and S-wave velocities). We report on Tikhonov   and TV regularization, a source frequency-content continuation scheme, regularization factor continuation, and search-direction biasing that are all used in order to assist the optimizer’s convergence.
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\nWe report numerical results for both synthetic and field-collected data. For the field studies, we also report on a validation approach that served as a strong indicator of the correctness of the reconstructed site profile.

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Danish pastry, coffee and tea will be served 15 minutes before the seminar starts.
\n  
\nAll interested persons are invited

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A DCAMM seminar will be presented by

\n

Professor Loukas Kallivokas

\n

The University of Texas at Austin, USA

\n

\n\n 

\n

Abstract: 
\n

\n

We discuss the development of a full-waveform-inversion-based methodology for the imaging of near-surface formations using sparse    data. Specifically, we address the imaging of arbitrarily heterogeneous sites in three dimensions, using elastic waves as probing agents      and the response of the site recorded at sparsely distributed surface sensors.
\n
\nWe cast the associated inverse medium problem directly in the time domain and use PDE-constrained optimization ideas to obtain the   profile of the probed site in terms of the spatially-distributed Lamé parameters (or the P- and S-wave velocities). We report on Tikhonov   and TV regularization, a source frequency-content continuation scheme, regularization factor continuation, and search-direction biasing that are all used in order to assist the optimizer’s convergence.
\n
\nWe report numerical results for both synthetic and field-collected data. For the field studies, we also report on a validation approach that served as a strong indicator of the correctness of the reconstructed site profile.

\n

Danish pastry, coffee and tea will be served 15 minutes before the seminar starts.
\n  
\nAll interested persons are invited

URL:http://www.dcamm.dk/kalender/2016/09/seminar_no_706 DTSTAMP:20260406T213400Z UID:{53F2C2CD-9B41-4EA4-B5D9-E07D75E4D739}-20160929T140000-20160929T140000 LOCATION: Room 105, Building 404, Technical University of Denmark END:VEVENT END:VCALENDAR