Search
Results
-
On generalization error estimates of physics informed neural networks for approximating dispersive PDEs
(2021)SAM Research ReportPhysics informed neural networks (PINNs) have recently been widely used for robust and accurate approximation of PDEs. We provide rigorous upper bounds on the generalization error of PINNs approximating solutions of the forward problem for several dispersive PDEs.Report -
Evaluierungs-Framework und Kriterienkatalog für digitale Gesundheitsinterventionen in der Schweiz
(2021)Im Mittelpunkt der heutigen öffentlichen Gesundheit steht die Digitalisierung. Digitale Gesundheitsinterventionen haben im 21. Jahrhundert mehr denn je die Aufgabe, die Prävention und das Management nichtübertragbarer Krankheiten im Alltag von Betroffenen zu unterstützen und existierende Gesundheitsdienstleistungen sinnvoll zu ergänzen. Es fehlen allerdings noch etablierte Richtlinien für die Entwicklung und Evaluation digitaler ...Report -
On universal approximation and error bounds for Fourier Neural Operators
(2021)SAM Research ReportFourier neural operators (FNOs) have recently been proposed as an effective framework for learning operators that map between infinite-dimensional spaces. We prove that FNOs are universal, in the sense that they can approximate any continuous operator to desired accuracy. Moreover, we suggest a mechanism by which FNOs can approximate operators associated with PDEs efficiently. Explicit error bounds are derived to show that the size of the ...Report -
Bernhard Riemann, the ear, and an atom of consciousness
(2021)SAM Research ReportWhy did Bernhard Riemann (1826–1866), arguably the most original mathematician of his generation, spend the last year of life investigating the mechanism of hearing? Fighting tuberculosis and the hostility of eminent scientists such as Hermann Helmholtz, he appeared to forsake mathematics to prosecute a case close to his heart. Only sketchy pages from his last paper remain, but here we assemble some significant clues and triangulate from ...Report -
On the well-posedness of Bayesian inversion for PDEs with ill-posed forward problems
(2021)SAM Research ReportWe study the well-posedness of Bayesian inverse problems for PDEs, for which the underlying forward problem may be ill-posed. Such PDEs, which include the fundamental equations of fluid dynamics, are characterized by the lack of rigorous global existence and stability results as well as possible non-convergence of numerical approximations. Under very general hypotheses on approximations to these PDEs, we prove that the posterior measure, ...Report -
Well-posedness of Bayesian inverse problems for hyperbolic conservation laws
(2021)SAM Research ReportWe study the well-posedness of the Bayesian inverse problem for scalar hyperbolic conservation laws where the statistical information about inputs such as the initial datum and (possibly discontinuous) flux function are inferred from noisy measurements. In particular, the Lipschitz continuity of the measurement to posterior map as well as the stability of the posterior to approximations, are established with respect to the Wasserstein ...Report -
Homogenization of sound-absorbing and high-contrast acoustic metamaterials in subcritical regimes
(2021)SAM Research ReportReport -
-
Teamwork in Antarctica
(2020)This document regards the report of the research project "Team Adaptation during Antarctica Summer Campaigns", supported by the Portuguese Polar Program (PROPOLAR). It contains general findings about teamwork in Antarctica and recommendations for practice.Report