no code implementations • 30 Oct 2023 • Nathael Da Costa, Cyrus Mostajeran, Juan-Pablo Ortega, Salem Said
This work aims to prove that the classical Gaussian kernel, when defined on a non-Euclidean symmetric space, is never positive-definite for any choice of parameter.
no code implementations • 20 Oct 2023 • Nathael Da Costa, Cyrus Mostajeran, Juan-Pablo Ortega, Salem Said
Classical kernel methods are based on positive-definite kernels, which map data spaces into reproducing kernel Hilbert spaces (RKHS).
no code implementations • 14 Apr 2023 • Cyrus Mostajeran, Nathaël Da Costa, Graham Van Goffrier, Rodolphe Sepulchre
Differential geometric approaches to the analysis and processing of data in the form of symmetric positive definite (SPD) matrices have had notable successful applications to numerous fields including computer vision, medical imaging, and machine learning.
no code implementations • 21 Feb 2023 • Nathaël Da Costa, Cyrus Mostajeran, Juan-Pablo Ortega
On Euclidean spaces, the Gaussian kernel is one of the most widely used kernels in applications.
no code implementations • 2 Jul 2022 • Berlin Chen, Cyrus Mostajeran, Salem Said
We present a novel algorithm for learning the parameters of hidden Markov models (HMMs) in a geometric setting where the observations take values in Riemannian manifolds.
no code implementations • 1 Mar 2022 • Salem Said, Simon Heuveline, Cyrus Mostajeran
Its main contribution is to prove that Riemannian Gaussian distributions of real, complex, or quaternion covariance matrices are equivalent to orthogonal, unitary, or symplectic log-normal matrix ensembles.
no code implementations • 6 Feb 2022 • Jin Gyu Lee, Cyrus Mostajeran, Graham Van Goffrier
We study a node-wise monotone barrier coupling law, motivated by the synaptic coupling of neural central pattern generators.
no code implementations • 15 Feb 2021 • Quinten Tupker, Salem Said, Cyrus Mostajeran
Hidden Markov models with observations in a Euclidean space play an important role in signal and image processing.
no code implementations • 2 Jun 2020 • Graham W. Van Goffrier, Cyrus Mostajeran, Rodolphe Sepulchre
Covariance data as represented by symmetric positive definite (SPD) matrices are ubiquitous throughout technical study as efficient descriptors of interdependent systems.