Search Results for author: Nicholas F. Marshall

Found 9 papers, 3 papers with code

Laplace-HDC: Understanding the geometry of binary hyperdimensional computing

no code implementations16 Apr 2024 Saeid Pourmand, Wyatt D. Whiting, Alireza Aghasi, Nicholas F. Marshall

This paper studies the geometry of binary hyperdimensional computing (HDC), a computational scheme in which data are encoded using high-dimensional binary vectors.

Translation

Moment-based metrics for molecules computable from cryo-EM images

1 code implementation26 Jan 2024 Andy Zhang, Oscar Mickelin, Joe Kileel, Eric J. Verbeke, Nicholas F. Marshall, Marc Aurèle Gilles, Amit Singer

Further, we introduce a metric between a stack of projection images and a molecular structure, which is invariant to rotations and reflections and does not require performing 3-D reconstruction.

Cryogenic Electron Microscopy (cryo-EM)

Randomized Kaczmarz with geometrically smoothed momentum

no code implementations17 Jan 2024 Seth J. Alderman, Roan W. Luikart, Nicholas F. Marshall

This paper studies the effect of adding geometrically smoothed momentum to the randomized Kaczmarz algorithm, which is an instance of stochastic gradient descent on a linear least squares loss function.

Fast expansion into harmonics on the disk: a steerable basis with fast radial convolutions

1 code implementation27 Jul 2022 Nicholas F. Marshall, Oscar Mickelin, Amit Singer

We present a fast and numerically accurate method for expanding digitized $L \times L$ images representing functions on $[-1, 1]^2$ supported on the disk $\{x \in \mathbb{R}^2 : |x|<1\}$ in the harmonics (Dirichlet Laplacian eigenfunctions) on the disk.

An optimal scheduled learning rate for a randomized Kaczmarz algorithm

no code implementations24 Feb 2022 Nicholas F. Marshall, Oscar Mickelin

We study how the learning rate affects the performance of a relaxed randomized Kaczmarz algorithm for solving $A x \approx b + \varepsilon$, where $A x =b$ is a consistent linear system and $\varepsilon$ has independent mean zero random entries.

A common variable minimax theorem for graphs

1 code implementation30 Jul 2021 Ronald R. Coifman, Nicholas F. Marshall, Stefan Steinerberger

Let $\mathcal{G} = \{G_1 = (V, E_1), \dots, G_m = (V, E_m)\}$ be a collection of $m$ graphs defined on a common set of vertices $V$ but with different edge sets $E_1, \dots, E_m$.

Multi-target detection with rotations

no code implementations19 Jan 2021 Tamir Bendory, Ti-Yen Lan, Nicholas F. Marshall, Iris Rukshin, Amit Singer

We demonstrate that, regardless of the level of noise, our technique can be used to recover the target image when the measurement is sufficiently large.

Image recovery from rotational and translational invariants

no code implementations22 Oct 2019 Nicholas F. Marshall, Ti-Yen Lan, Tamir Bendory, Amit Singer

We introduce a framework for recovering an image from its rotationally and translationally invariant features based on autocorrelation analysis.

Manifold learning with bi-stochastic kernels

no code implementations17 Nov 2017 Nicholas F. Marshall, Ronald R. Coifman

In this paper we answer the following question: what is the infinitesimal generator of the diffusion process defined by a kernel that is normalized such that it is bi-stochastic with respect to a specified measure?

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