Non-negative matrix factorization and topic models

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Abstract/Contents

Abstract
Matrix factorization algorithms provide a powerful tool for data analysis and statistical inference. As an important class of these algorithms, nonnegative matrix factorization (NMF) suggests expressing a collection of data points as convex combinations of a small set of 'archetypes' with nonnegative entries. As a result, NMF enables us to extract the latent structure and underlying 'pure components' in a broad range of applications from chemometrics to image processing and topic modeling. In this thesis, we study the NMF problem from two different perspectives: 1. We consider the NMF problem under a deterministic model and propose a new estimator that robustly recovers the factors under a more general settings than the state-of-the-art estimators, with theoretical guarantees. 2. We analyze the NMF problem in a Bayesian setting under which the data is generated using an LDA model. We show negative results about variational inference in this problem, showing that it is not 'stable'. In particular, we show that in a certain region for signal-to-noise ratio, in which the underlying signal cannot be recovered, the variational method is randomly biased and outputs a non-trivial solution. This output, of course, is uncorrelated with the underlying truth. We also suggest a possible correction to remedy this issue.

Description

Type of resource text
Form electronic resource; remote; computer; online resource
Extent 1 online resource.
Place California
Place [Stanford, California]
Publisher [Stanford University]
Copyright date 2018; ©2018
Publication date 2018; 2018
Issuance monographic
Language English

Creators/Contributors

Author Hakim Javadi, Hamidreza
Degree supervisor Montanari, Andrea
Thesis advisor Montanari, Andrea
Thesis advisor Boyd, Stephen P
Thesis advisor Candès, Emmanuel J. (Emmanuel Jean)
Thesis advisor Weissman, Tsachy
Degree committee member Boyd, Stephen P
Degree committee member Candès, Emmanuel J. (Emmanuel Jean)
Degree committee member Weissman, Tsachy
Associated with Stanford University, Department of Electrical Engineering.

Subjects

Genre Theses
Genre Text

Bibliographic information

Statement of responsibility Hamidreza Hakim Javadi.
Note Submitted to the Department of Electrical Engineering.
Thesis Thesis Ph.D. Stanford University 2018.
Location electronic resource

Access conditions

Copyright
© 2018 by Hamidreza Hakim Javadi
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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