Title
On novelty detection for multi-class classification using non-linear metric learning
Abstract
Novelty detection is a binary task aimed at identifying whether a test sample is novel or unusual compared to a previously observed training set. A typical approach is to consider distance as a criterion to detect such novelties. However, most previous work does not focus on finding an optimum distance for each particular problem. In this paper, we propose to detect novelties by exploiting non-linear distances learned from multi-class training data. For this purpose, we adopt a kernelization technique jointly with the Large Margin Nearest Neighbor (LMNN) metric learning algorithm. The optimum distance tries to keep each known class’ instances together while pushing instances from different known classes to remain reasonably distant. We propose a variant of the K-Nearest Neighbors (KNN) classifier that employs the learned distance to detect novelties. Besides, we use the learned distance to perform multi-class classification. We show quantitative and qualitative experiments conducted on synthetic and real data sets, revealing that the learned metrics are effective in improving novelty detection compared to other metrics. Our method also outperforms previous work regularly used for novelty detection.
Year
DOI
Venue
2021
10.1016/j.eswa.2020.114193
Expert Systems with Applications
Keywords
DocType
Volume
Novelty detection,Outlier detection,Anomaly detection,Metric learning,Multi-class classification
Journal
167
ISSN
Citations 
PageRank 
0957-4174
0
0.34
References 
Authors
0
4
Name
Order
Citations
PageRank
Samuel Rocha Silva100.34
Thales Vieira2968.25
Dimas Martínez3955.90
Afonso Paiva413516.76