Search Results for author: Roy R. Lederman

Found 12 papers, 4 papers with code

On Manifold Learning in Plato's Cave: Remarks on Manifold Learning and Physical Phenomena

1 code implementation27 Apr 2023 Roy R. Lederman, Bogdan Toader

Many techniques in machine learning attempt explicitly or implicitly to infer a low-dimensional manifold structure of an underlying physical phenomenon from measurements without an explicit model of the phenomenon or the measurement apparatus.

Dimensionality Reduction

Using VAEs to Learn Latent Variables: Observations on Applications in cryo-EM

1 code implementation13 Mar 2023 Daniel G. Edelberg, Roy R. Lederman

Variational autoencoders (VAEs) are a popular generative model used to approximate distributions.

Geometric Ergodicity in Modified Variations of Riemannian Manifold and Lagrangian Monte Carlo

no code implementations4 Jan 2023 James A. Brofos, Vivekananda Roy, Roy R. Lederman

Unlike Euclidean Hamiltonian Monte Carlo (EHMC) and the Metropolis-adjusted Langevin algorithm (MALA), the geometric ergodicity of these Riemannian algorithms has not been extensively studied.

Bayesian Inference

Methods for Cryo-EM Single Particle Reconstruction of Macromolecules having Continuous Heterogeneity

no code implementations19 Nov 2022 Bogdan Toader, Fred J. Sigworth, Roy R. Lederman

Macromolecules change their shape (conformation) in the process of carrying out their functions.

Magnetic Manifold Hamiltonian Monte Carlo

no code implementations15 Oct 2020 James A. Brofos, Roy R. Lederman

We introduce magnetic manifold HMC, an HMC algorithm on embedded manifolds motivated by the physics of particles constrained to a manifold and moving under magnetic field forces.

Spectral Flow on the Manifold of SPD Matrices for Multimodal Data Processing

1 code implementation17 Sep 2020 Ori Katz, Roy R. Lederman, Ronen Talmon

Our approach combines manifold learning, which is a class of nonlinear data-driven dimension reduction methods, with the well-known Riemannian geometry of symmetric and positive-definite (SPD) matrices.

Dimensionality Reduction

Non-Canonical Hamiltonian Monte Carlo

no code implementations18 Aug 2020 James A. Brofos, Roy R. Lederman

Hamiltonian Monte Carlo is typically based on the assumption of an underlying canonical symplectic structure.

Hyper-Molecules: on the Representation and Recovery of Dynamical Structures, with Application to Flexible Macro-Molecular Structures in Cryo-EM

no code implementations2 Jul 2019 Roy R. Lederman, Joakim andén, Amit Singer

We introduce the ``hyper-molecule'' framework for modeling structures across different states of heterogeneous molecules, including continuums of states.

Numerical Algorithms for the Computation of Generalized Prolate Spheroidal Functions

2 code implementations8 Oct 2017 Roy R. Lederman

The purpose of this paper is to review the elements of computing GPSFs and associated eigenvalues.

Numerical Analysis Numerical Analysis 42A38, 65T99, 33F05, 65D20

Continuously heterogeneous hyper-objects in cryo-EM and 3-D movies of many temporal dimensions

no code implementations10 Apr 2017 Roy R. Lederman, Amit Singer

One of the great opportunities in cryo-EM is to recover the structure of macromolecules in heterogeneous samples, where multiple types or multiple conformations are mixed together.

A Representation Theory Perspective on Simultaneous Alignment and Classification

no code implementations12 Jul 2016 Roy R. Lederman, Amit Singer

One of the difficulties in 3D reconstruction of molecules from images in single particle Cryo-Electron Microscopy (Cryo-EM), in addition to high levels of noise and unknown image orientations, is heterogeneity in samples: in many cases, the samples contain a mixture of molecules, or multiple conformations of one molecule.

3D Reconstruction Classification +1

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