Search Results for author: Gianluca Fabiani

Found 10 papers, 0 papers with code

Random Projection Neural Networks of Best Approximation: Convergence theory and practical applications

no code implementations17 Feb 2024 Gianluca Fabiani

We investigate the concept of Best Approximation for Feedforward Neural Networks (FNN) and explore their convergence properties through the lens of Random Projection (RPNNs).

Computational Efficiency

Tasks Makyth Models: Machine Learning Assisted Surrogates for Tipping Points

no code implementations25 Sep 2023 Gianluca Fabiani, Nikolaos Evangelou, Tianqi Cui, Juan M. Bello-Rivas, Cristina P. Martin-Linares, Constantinos Siettos, Ioannis G. Kevrekidis

We present a machine learning (ML)-assisted framework bridging manifold learning, neural networks, Gaussian processes, and Equation-Free multiscale modeling, for (a) detecting tipping points in the emergent behavior of complex systems, and (b) characterizing probabilities of rare events (here, catastrophic shifts) near them.

Gaussian Processes

Slow Invariant Manifolds of Singularly Perturbed Systems via Physics-Informed Machine Learning

no code implementations14 Sep 2023 Dimitrios G. Patsatzis, Gianluca Fabiani, Lucia Russo, Constantinos Siettos

A comparison of the computational costs between symbolic, automatic and numerical approximation of the required derivatives in the learning process is also provided.

Numerical Integration Physics-informed machine learning

Discrete-Time Nonlinear Feedback Linearization via Physics-Informed Machine Learning

no code implementations15 Mar 2023 Hector Vargas Alvarez, Gianluca Fabiani, Nikolaos Kazantzis, Constantinos Siettos, Ioannis G. Kevrekidis

We assess the performance of the proposed PIML approach via a benchmark nonlinear discrete map for which the feedback linearization transformation law can be derived analytically; the example is characterized by steep gradients, due to the presence of singularities, in the domain of interest.

Physics-informed machine learning

Parsimonious Physics-Informed Random Projection Neural Networks for Initial-Value Problems of ODEs and index-1 DAEs

no code implementations10 Mar 2022 Gianluca Fabiani, Evangelos Galaris, Lucia Russo, Constantinos Siettos

The unknown weights between the hidden and output layer are computed by Newton's iterations, using the Moore-Penrose pseudoinverse for low to medium, and sparse QR decomposition with regularization for medium to large scale systems.

Constructing coarse-scale bifurcation diagrams from spatio-temporal observations of microscopic simulations: A parsimonious machine learning approach

no code implementations31 Jan 2022 Evangelos Galaris, Gianluca Fabiani, Ioannis Gallos, Ioannis Kevrekidis, Constantinos Siettos

For our illustrations, we implemented the proposed method to construct the one-parameter bifurcation diagram of the 1D FitzHugh-Nagumo PDEs from data generated by $D1Q3$ Lattice Boltzmann simulations.

feature selection

Numerical Solution of Stiff ODEs with Physics-Informed RPNNs

no code implementations3 Aug 2021 Evangelos Galaris, Gianluca Fabiani, Francesco Calabrò, Daniela di Serafino, Constantinos Siettos

We propose a numerical method based on physics-informed Random Projection Neural Networks for the solution of Initial Value Problems (IVPs) of Ordinary Differential Equations (ODEs) with a focus on stiff problems.

Extreme learning machine collocation for the numerical solution of elliptic PDEs with sharp gradients

no code implementations10 Dec 2020 Francesco Calabrò, Gianluca Fabiani, Constantinos Siettos

We show that a feedforward neural network with a single hidden layer with sigmoidal functions and fixed, random, internal weights and biases can be used to compute accurately a collocation solution.

Numerical Analysis Numerical Analysis

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