Boosting Anomaly Detection Using Unsupervised Diverse Test-Time Augmentation

Fuente: arXiv
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Auteurs principaux: Cohen, Seffi, Goldshlager, Niv, Rokach, Lior, Shapira, Bracha
Format: Preprint
Publié: 2021
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author Cohen, Seffi
Goldshlager, Niv
Rokach, Lior
Shapira, Bracha
author_facet Cohen, Seffi
Goldshlager, Niv
Rokach, Lior
Shapira, Bracha
contents Anomaly detection is a well-known task that involves the identification of abnormal events that occur relatively infrequently. Methods for improving anomaly detection performance have been widely studied. However, no studies utilizing test-time augmentation (TTA) for anomaly detection in tabular data have been performed. TTA involves aggregating the predictions of several synthetic versions of a given test sample; TTA produces different points of view for a specific test instance and might decrease its prediction bias. We propose the Test-Time Augmentation for anomaly Detection (TTAD) technique, a TTA-based method aimed at improving anomaly detection performance. TTAD augments a test instance based on its nearest neighbors; various methods, including the k-Means centroid and SMOTE methods, are used to produce the augmentations. Our technique utilizes a Siamese network to learn an advanced distance metric when retrieving a test instance's neighbors. Our experiments show that the anomaly detector that uses our TTA technique achieved significantly higher AUC results on all datasets evaluated.
format Preprint
id arxiv_https___arxiv_org_abs_2110_15700
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Boosting Anomaly Detection Using Unsupervised Diverse Test-Time Augmentation
Cohen, Seffi
Goldshlager, Niv
Rokach, Lior
Shapira, Bracha
Machine Learning
Anomaly detection is a well-known task that involves the identification of abnormal events that occur relatively infrequently. Methods for improving anomaly detection performance have been widely studied. However, no studies utilizing test-time augmentation (TTA) for anomaly detection in tabular data have been performed. TTA involves aggregating the predictions of several synthetic versions of a given test sample; TTA produces different points of view for a specific test instance and might decrease its prediction bias. We propose the Test-Time Augmentation for anomaly Detection (TTAD) technique, a TTA-based method aimed at improving anomaly detection performance. TTAD augments a test instance based on its nearest neighbors; various methods, including the k-Means centroid and SMOTE methods, are used to produce the augmentations. Our technique utilizes a Siamese network to learn an advanced distance metric when retrieving a test instance's neighbors. Our experiments show that the anomaly detector that uses our TTA technique achieved significantly higher AUC results on all datasets evaluated.
title Boosting Anomaly Detection Using Unsupervised Diverse Test-Time Augmentation
topic Machine Learning
url https://arxiv.org/abs/2110.15700