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Archive / INF Seminars / INF_2025_04_29_LauraScarabosio

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	Forward and inverse shape uncertainty quantification in time-harmonic scattering

Host: Prof. Michael Multerer

Tuesday

29.04

USI Campus EST, Room D0.02

15:30 - 16:30


	Laura Scarabosio Radboud University, The Netherlands

Abstract: We study wave scattering from an object with uncertain shape, illuminated by a time-harmonic wave - such as sound or light - from which we observe the resulting scattered field. The physics relating the shape to the scattering response is modeled by the Helmholtz equation. We first address the forward problem, namely the quantification of the uncertainty propagated from the shape to the scattering response. This task is computationally expensive, due to the high dimensionality of the space of uncertain parameters and the need to solve the Helmholtz equation for many realizations. We discuss strategies to mitigate both challenges, either constructing approximations in the parameter space or exploiting correlations between different PDE solves to accelerate the repeated solutions of the Helmholtz equation. We then move to the task of reducing the uncertainty in the shape using information from measurements of the scattered field, which we cast in the framework of a Bayesian inverse problem. We study its well-posedness as well as numerical methods to sample from the Bayesian posterior, with particular focus on the role of the frequency of excitation on the stability of the inversion.

Biography: Laura Scarabosio is currently assistant professor at Radboud University (Nijmegen, The Netherlands). She completed her PhD in Mathematics from ETH Zürich in 2016 under the supervision of Ralf Hiptmair and co-supervision of Christoph Schwab. She spent four years as postdoctoral researcher at TU Münich, when she also conducted research visits at the Oden Institute at UT Austin. Her research interests cover shape uncertainty quantification, uncertainty quantification in time-harmonic scattering, Bayesian inverse problems, and applications in biology, power cable operation and multiscale materials.