A neural network with feature sparsity

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Abstract/Contents

Abstract
First, we propose a neural network model with a separate linear (residual) term, that explicitly bounds the input layer weights for a feature by the linear weight for that feature. The model can be seen as a modification of so-called residual neural networks to produce a path of models that are feature- sparse, that is, use only a subset of the features. This is analogous to the solution path from the usual Lasso (L1-regularized) linear regression. We call the proposed procedure LassoNet and develop a projected proximal gradient algorithm for its optimization. This approach can sometimes give as low or lower test error than a standard neural network, and its feature selection provides more interpretable solutions. This thesis illustrates the method using both simulated and real data examples, and shows that it is often able to achieve competitive performance with a much smaller number of input features. We also discuss extensions of this work beyond supervised learning, which includes unsupervised learning, matrix completion, and sparsity in learned features. Second, we consider the problem of local feature attribution and selection for arbitrary black-box models. We introduce a geometric method which we call RbX, for Region-Based Explanations. This method relies on approximating the prediction model's level sets by convex polytopes, thus helping to simplify and interpret the model. We demonstrate the effectiveness of the method on a variety of synthetic and real data sets.

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 2021; ©2021
Publication date 2021; 2021
Issuance monographic
Language English

Creators/Contributors

Author Lemhadri, Ismael
Degree supervisor Tibshirani, Robert
Thesis advisor Tibshirani, Robert
Thesis advisor Duchi, John
Thesis advisor Hastie, Trevor
Degree committee member Duchi, John
Degree committee member Hastie, Trevor
Associated with Stanford University, Department of Statistics

Subjects

Genre Theses
Genre Text

Bibliographic information

Statement of responsibility Ismael Lemhadri.
Note Submitted to the Department of Statistics.
Thesis Thesis Ph.D. Stanford University 2021.
Location https://purl.stanford.edu/yk085xh9902

Access conditions

Copyright
© 2021 by Ismael Lemhadri
License
This work is licensed under a Creative Commons Attribution 3.0 Unported license (CC BY).

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