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Statistical solutions of hyperbolic systems of conservation laws: numerical approximation
(2019)SAM Research ReportReport -
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Arbitrarily high-order (weighted) essentially non-oscillatory finite difference schemes for anelastic flows on staggered meshes
(2019)SAM Research ReportReport -
Entropy stability and well-balancedness of space-time DG for the shallow water equations with bottom topography
(2015)Research ReportWe describe a shock-capturing streamline diffusion space-time discontinuous Galerkin (DG) method to discretize the shallow water equations with variable bottom topography. This method, based on the entropy variables as degrees of freedom, is shown to be energy stable as well as well-balanced with respect to the lake at rest steady state. We present numerical experiments illustrating the numerical method.Report -
Statistical solutions of hyperbolic conservation laws I: Foundations
(2016)Research ReportReport -
Schemes with well-controlled dissipation-Hyperbolic systems in non-conservative form
(2015)Research reportsReport -
Schemes with Well controlled Dissipation (WCD) I
(2013)Research ReportWe consider the approximation of entropy solutions to nonlinear hyperbolic conservation laws, in the regime that small–scale effects drive the dynamics of shock waves in these solutions. We introduce and analyze a new class of numerical methods, referred to as the schemes with well-controled dissipation (WCD), which approximate entropy solutions with high–accuracy and can capture small scale dependent shock waves of arbitrary strength. ...Report -
Generic bounds on the approximation error for physics-informed (and) operator learning
(2022)SAM Research ReportWe propose a very general framework for deriving rigorous bounds on the approximation error for physics-informed neural networks (PINNs) and operator learning architectures such as DeepONets and FNOs as well as for physics-informed operator learning. These bounds guarantee that PINNs and (physics-informed) DeepONets or FNOs will efficiently approximate the underlying solution or solution operator of generic partial differential equations ...Report -
Coupled Oscillatory Recurrent Neural Network (coRNN): An accurate and (gradient) stable architecture for learning long time dependencies
(2020)SAM Research ReportCircuits of biological neurons, such as in the functional parts of the brain can be modeled as networks of coupled oscillators. Inspired by the ability of these systems to express a rich set of outputs while keeping (gradients of) state variables bounded, we propose a novel architecture for recurrent neural networks. Our proposed RNN is based on a time-discretization of a system of second-order ordinary differential equations, modeling ...Report -
Numerical solution of scalar conservation laws with random flux functions
(2012)Research ReportWe consider scalar hyperbolic conservation laws in several space dimensions, with a class of random (and parametric) flux functions. We propose a Karhunen–Loève expansion on the state space of the random flux. For random flux functions which are Lipschitz continuous with respect to the state variable, we prove the existence of a unique random entropy solution. Using a Karhunen–Loève spectral decomposition of the random flux into principal ...Report