Search Results for author: Demba Ba

Found 27 papers, 9 papers with code

Clustering Inductive Biases with Unrolled Networks

no code implementations30 Nov 2023 Jonathan Huml, Abiy Tasissa, Demba Ba

We propose an autoencoder architecture (WLSC) whose latent representations are implicitly, locally organized for spectral clustering through a Laplacian quadratic form of a bipartite graph, which generates a diverse set of artificial receptive fields that match primate data in V1 as faithfully as recent contrastive frameworks like Local Low Dimensionality, or LLD \citep{lld} that discard sparse dictionary learning.

Clustering Dictionary Learning +1

An Efficient Algorithm for Clustered Multi-Task Compressive Sensing

1 code implementation30 Sep 2023 Alexander Lin, Demba Ba

This paper considers clustered multi-task compressive sensing, a hierarchical model that solves multiple compressive sensing tasks by finding clusters of tasks that leverage shared information to mutually improve signal reconstruction.

Compressive Sensing

Probabilistic Unrolling: Scalable, Inverse-Free Maximum Likelihood Estimation for Latent Gaussian Models

no code implementations5 Jun 2023 Alexander Lin, Bahareh Tolooshams, Yves Atchadé, Demba Ba

Latent Gaussian models have a rich history in statistics and machine learning, with applications ranging from factor analysis to compressed sensing to time series analysis.

Time Series Time Series Analysis

Learning Linear Groups in Neural Networks

no code implementations29 May 2023 Emmanouil Theodosis, Karim Helwani, Demba Ba

Employing equivariance in neural networks leads to greater parameter efficiency and improved generalization performance through the encoding of domain knowledge in the architecture; however, the majority of existing approaches require an a priori specification of the desired symmetries.

Sparse, Geometric Autoencoder Models of V1

no code implementations22 Feb 2023 Jonathan Huml, Abiy Tasissa, Demba Ba

The classical sparse coding model represents visual stimuli as a linear combination of a handful of learned basis functions that are Gabor-like when trained on natural image data.

Dictionary Learning

Learning unfolded networks with a cyclic group structure

1 code implementation16 Nov 2022 Emmanouil Theodosis, Demba Ba

Deep neural networks lack straightforward ways to incorporate domain knowledge and are notoriously considered black boxes.

Data Augmentation Rotated MNIST

Unrolled Compressed Blind-Deconvolution

no code implementations28 Sep 2022 Bahareh Tolooshams, Satish Mulleti, Demba Ba, Yonina C. Eldar

To reduce its computational and implementation cost, we propose a compression method that enables blind recovery from much fewer measurements with respect to the full received signal in time.

Mixture Model Auto-Encoders: Deep Clustering through Dictionary Learning

1 code implementation10 Oct 2021 Alexander Lin, Andrew H. Song, Demba Ba

State-of-the-art approaches for clustering high-dimensional data utilize deep auto-encoder architectures.

Clustering Deep Clustering +1

Stable and Interpretable Unrolled Dictionary Learning

1 code implementation31 May 2021 Bahareh Tolooshams, Demba Ba

The success of dictionary learning relies on access to a "good" initial estimate of the dictionary and the ability of the sparse coding step to provide an unbiased estimate of the code.

Dictionary Learning Image Denoising +1

Covariance-Free Sparse Bayesian Learning

no code implementations21 May 2021 Alexander Lin, Andrew H. Song, Berkin Bilgic, Demba Ba

The most popular inference algorithms for SBL exhibit prohibitively large computational costs for high-dimensional problems due to the need to maintain a large covariance matrix.

MRI Reconstruction Uncertainty Quantification

Weighed $\ell_1$ on the simplex: Compressive sensing meets locality

no code implementations28 Apr 2021 Abiy Tasissa, Pranay Tankala, Demba Ba

Sparse manifold learning algorithms combine techniques in manifold learning and sparse optimization to learn features that could be utilized for downstream tasks.

Compressive Sensing

Gaussian Process Convolutional Dictionary Learning

no code implementations28 Mar 2021 Andrew H. Song, Bahareh Tolooshams, Demba Ba

Convolutional dictionary learning (CDL), the problem of estimating shift-invariant templates from data, is typically conducted in the absence of a prior/structure on the templates.

Dictionary Learning Gaussian Processes

On the convergence of group-sparse autoencoders

no code implementations13 Feb 2021 Emmanouil Theodosis, Bahareh Tolooshams, Pranay Tankala, Abiy Tasissa, Demba Ba

Recent approaches in the theoretical analysis of model-based deep learning architectures have studied the convergence of gradient descent in shallow ReLU networks that arise from generative models whose hidden layers are sparse.

Clustering

K-Deep Simplex: Deep Manifold Learning via Local Dictionaries

1 code implementation3 Dec 2020 Pranay Tankala, Abiy Tasissa, James M. Murphy, Demba Ba

We theoretically analyze the proposed program by relating the weighted $\ell_1$ penalty in KDS to a weighted $\ell_0$ program.

Clustering Deep Clustering +2

Unfolding Neural Networks for Compressive Multichannel Blind Deconvolution

no code implementations22 Oct 2020 Bahareh Tolooshams, Satish Mulleti, Demba Ba, Yonina C. Eldar

We propose a learned-structured unfolding neural network for the problem of compressive sparse multichannel blind-deconvolution.

Towards improving discriminative reconstruction via simultaneous dense and sparse coding

no code implementations16 Jun 2020 Abiy Tasissa, Emmanouil Theodosis, Bahareh Tolooshams, Demba Ba

We propose a novel dense and sparse coding model that integrates both representation capability and discriminative features.

Compressive Sensing Dictionary Learning

RandNet: deep learning with compressed measurements of images

no code implementations25 Aug 2019 Thomas Chang, Bahareh Tolooshams, Demba Ba

We introduce a class of neural networks, termed RandNet, for learning representations using compressed random measurements of data of interest, such as images.

Dictionary Learning

Convolutional Dictionary Learning in Hierarchical Networks

no code implementations23 Jul 2019 Javier Zazo, Bahareh Tolooshams, Demba Ba

Motivated by the empirically observed properties of scale and detail coefficients of images in the wavelet domain, we propose a hierarchical deep generative model of piecewise smooth signals that is a recursion across scales: the low pass scale coefficients at one layer are obtained by filtering the scale coefficients at the next layer, and adding a high pass detail innovation obtained by filtering a sparse vector.

Dictionary Learning

Fast Convolutional Dictionary Learning off the Grid

no code implementations22 Jul 2019 Andrew H. Song, Francisco J. Flores, Demba Ba

Given a continuous-time signal that can be modeled as the superposition of localized, time-shifted events from multiple sources, the goal of Convolutional Dictionary Learning (CDL) is to identify the location of the events--by Convolutional Sparse Coding (CSC)--and learn the template for each source--by Convolutional Dictionary Update (CDU).

Dictionary Learning Spike Sorting

Deep Residual Autoencoders for Expectation Maximization-inspired Dictionary Learning

1 code implementation18 Apr 2019 Bahareh Tolooshams, Sourav Dey, Demba Ba

Specifically, we leverage the interpretation of the alternating-minimization algorithm for dictionary learning as an approximate Expectation-Maximization algorithm to develop autoencoders that enable the simultaneous training of the dictionary and regularization parameter (ReLU bias).

Dictionary Learning Image Denoising

Clustering Time Series with Nonlinear Dynamics: A Bayesian Non-Parametric and Particle-Based Approach

no code implementations23 Oct 2018 Alexander Lin, Yingzhuo Zhang, Jeremy Heng, Stephen A. Allsop, Kay M. Tye, Pierre E. Jacob, Demba Ba

We propose a general statistical framework for clustering multiple time series that exhibit nonlinear dynamics into an a-priori-unknown number of sub-groups.

Bayesian Inference Clustering +2

Scalable Convolutional Dictionary Learning with Constrained Recurrent Sparse Auto-encoders

1 code implementation12 Jul 2018 Bahareh Tolooshams, Sourav Dey, Demba Ba

We demonstrate the ability of CRsAE to recover the underlying dictionary and characterize its sensitivity as a function of SNR.

blind source separation Dictionary Learning +1

Deeply-Sparse Signal rePresentations ($\text{D}\text{S}^2\text{P}$)

no code implementations5 Jul 2018 Demba Ba

A recent line of work shows that a deep neural network with ReLU nonlinearities arises from a finite sequence of cascaded sparse coding models, the outputs of which, except for the last element in the cascade, are sparse and unobservable.

Dictionary Learning

Multitaper Spectral Estimation HDP-HMMs for EEG Sleep Inference

no code implementations18 May 2018 Leon Chlon, Andrew Song, Sandya Subramanian, Hugo Soulat, John Tauber, Demba Ba, Michael Prerau

Electroencephalographic (EEG) monitoring of neural activity is widely used for sleep disorder diagnostics and research.

EEG Time Series +1

Exact and Stable Recovery of Sequences of Signals with Sparse Increments via Differential _1-Minimization

no code implementations NeurIPS 2012 Demba Ba, Behtash Babadi, Patrick Purdon, Emery Brown

We consider the problem of recovering a sequence of vectors, $(x_k)_{k=0}^K$, for which the increments $x_k-x_{k-1}$ are $S_k$-sparse (with $S_k$ typically smaller than $S_1$), based on linear measurements $(y_k = A_k x_k + e_k)_{k=1}^K$, where $A_k$ and $e_k$ denote the measurement matrix and noise, respectively.

Compressive Sensing

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