Search Results for author: Cyrus Mostajeran

Found 9 papers, 0 papers with code

Invariant kernels on Riemannian symmetric spaces: a harmonic-analytic approach

no code implementations30 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.

Geometric Learning with Positively Decomposable Kernels

no code implementations20 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).

Differential geometry with extreme eigenvalues in the positive semidefinite cone

no code implementations14 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.

The Gaussian kernel on the circle and spaces that admit isometric embeddings of the circle

no code implementations21 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.

Geometric Learning of Hidden Markov Models via a Method of Moments Algorithm

no code implementations2 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.

Riemannian statistics meets random matrix theory: towards learning from high-dimensional covariance matrices

no code implementations1 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.

Node-wise monotone barrier coupling law for formation control

no code implementations6 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.

Online learning of Riemannian hidden Markov models in homogeneous Hadamard spaces

no code implementations15 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.

Inductive Geometric Matrix Midranges

no code implementations2 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.

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