Search Results for author: Dimitrios Loukrezis

Found 8 papers, 3 papers with code

Polynomial Chaos Expansions on Principal Geodesic Grassmannian Submanifolds for Surrogate Modeling and Uncertainty Quantification

no code implementations30 Jan 2024 Dimitris G. Giovanis, Dimitrios Loukrezis, Ioannis G. Kevrekidis, Michael D. Shields

To this end, we employ Principal Geodesic Analysis on the Grassmann manifold of the response to identify a set of disjoint principal geodesic submanifolds, of possibly different dimension, that captures the variation in the data.

Uncertainty Quantification

Quadrupole Magnet Design based on Genetic Multi-Objective Optimization

no code implementations17 Nov 2022 Eric Diehl, Moritz von Tresckow, Lou Scholtissek, Dimitrios Loukrezis, Nicolas Marsic, Wolfgang F. O. Müller, Herbert De Gersem

This work suggests to optimize the geometry of a quadrupole magnet by means of a genetic algorithm adapted to solve multi-objective optimization problems.

A survey of unsupervised learning methods for high-dimensional uncertainty quantification in black-box-type problems

no code implementations9 Feb 2022 Katiana Kontolati, Dimitrios Loukrezis, Dimitris G. Giovanis, Lohit Vandanapu, Michael D. Shields

Constructing surrogate models for uncertainty quantification (UQ) on complex partial differential equations (PDEs) having inherently high-dimensional $\mathcal{O}(10^{\ge 2})$ stochastic inputs (e. g., forcing terms, boundary conditions, initial conditions) poses tremendous challenges.

blind source separation Dimensionality Reduction +1

Grassmannian diffusion maps based surrogate modeling via geometric harmonics

no code implementations28 Sep 2021 Ketson R. M. dos Santos, Dimitrios G. Giovanis, Katiana Kontolati, Dimitrios Loukrezis, Michael D. Shields

Using this representation, geometric harmonics, an out-of-sample function extension technique, is employed to create a global map from the space of input parameters to a Grassmannian diffusion manifold.

Uncertainty Quantification

Manifold learning-based polynomial chaos expansions for high-dimensional surrogate models

2 code implementations21 Jul 2021 Katiana Kontolati, Dimitrios Loukrezis, Ketson R. M. dos Santos, Dimitrios G. Giovanis, Michael D. Shields

For this purpose, we employ Grassmannian diffusion maps, a two-step nonlinear dimension reduction technique which allows us to reduce the dimensionality of the data and identify meaningful geometric descriptions in a parsimonious and inexpensive manner.

Dimensionality Reduction Uncertainty Quantification +1

Robust Adaptive Least Squares Polynomial Chaos Expansions in High-Frequency Applications

1 code implementation16 Dec 2019 Dimitrios Loukrezis, Armin Galetzka, Herbert De Gersem

We present an algorithm for computing sparse, least squares-based polynomial chaos expansions, incorporating both adaptive polynomial bases and sequential experimental designs.

Computational Engineering, Finance, and Science

Uncertainty quantification for an optical grating coupler with an adjoint-based Leja adaptive collocation method

no code implementations19 Jul 2018 Niklas Georg, Dimitrios Loukrezis, Ulrich Römer, Sebastian Schöps

By combining the Leja adaptive algorithm with an adjoint-based error indicator, an even smaller complexity is obtained.

Computational Engineering, Finance, and Science Numerical Analysis Computational Physics Optics 60H15, 60H35, 65N30, 78A40, 78M10 I.6.3; J.2; G.1.8

Assessing the Performance of Leja and Clenshaw-Curtis Collocation for Computational Electromagnetics with Random Input Data

1 code implementation19 Dec 2017 Dimitrios Loukrezis, Ulrich Römer, Herbert De Gersem

We consider the problem of quantifying uncertainty regarding the output of an electromagnetic field problem in the presence of a large number of uncertain input parameters.

Computational Engineering, Finance, and Science Numerical Analysis Numerical Analysis Computation 78Axx, 65D30, 65D32, 65D15, 65D05, 68U20, 65C20

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