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Main Authors: Uematsu, Kazuki, Haruki, Kosuke, Suzuki, Taiji, Kimura, Mitsuhiro, Takimoto, Takahiro, Nakagawa, Hideyuki
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2410.21656
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author Uematsu, Kazuki
Haruki, Kosuke
Suzuki, Taiji
Kimura, Mitsuhiro
Takimoto, Takahiro
Nakagawa, Hideyuki
author_facet Uematsu, Kazuki
Haruki, Kosuke
Suzuki, Taiji
Kimura, Mitsuhiro
Takimoto, Takahiro
Nakagawa, Hideyuki
contents Out-of-distribution (OOD) detection is a critical issue for the stable and reliable operation of systems using a deep neural network (DNN). Although many OOD detection methods have been proposed, it remains unclear how the differences between in-distribution (ID) and OOD samples are generated by each processing step inside DNNs. We experimentally clarify this issue by investigating the layer dependence of feature representations from multiple perspectives. We find that intrinsic low dimensionalization of DNNs is essential for understanding how OOD samples become more distinct from ID samples as features propagate to deeper layers. Based on these observations, we provide a simple picture that consistently explains various properties of OOD samples. Specifically, low-dimensional weights eliminate most information from OOD samples, resulting in misclassifications due to excessive attention to dataset bias. In addition, we demonstrate the utility of dimensionality by proposing a dimensionality-aware OOD detection method based on alignment of features and weights, which consistently achieves high performance for various datasets with lower computational cost.
format Preprint
id arxiv_https___arxiv_org_abs_2410_21656
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Dimensionality-induced information loss of outliers in deep neural networks
Uematsu, Kazuki
Haruki, Kosuke
Suzuki, Taiji
Kimura, Mitsuhiro
Takimoto, Takahiro
Nakagawa, Hideyuki
Machine Learning
Out-of-distribution (OOD) detection is a critical issue for the stable and reliable operation of systems using a deep neural network (DNN). Although many OOD detection methods have been proposed, it remains unclear how the differences between in-distribution (ID) and OOD samples are generated by each processing step inside DNNs. We experimentally clarify this issue by investigating the layer dependence of feature representations from multiple perspectives. We find that intrinsic low dimensionalization of DNNs is essential for understanding how OOD samples become more distinct from ID samples as features propagate to deeper layers. Based on these observations, we provide a simple picture that consistently explains various properties of OOD samples. Specifically, low-dimensional weights eliminate most information from OOD samples, resulting in misclassifications due to excessive attention to dataset bias. In addition, we demonstrate the utility of dimensionality by proposing a dimensionality-aware OOD detection method based on alignment of features and weights, which consistently achieves high performance for various datasets with lower computational cost.
title Dimensionality-induced information loss of outliers in deep neural networks
topic Machine Learning
url https://arxiv.org/abs/2410.21656