Title
Bagged One-Class Classifiers In The Presence Of Outliers
Abstract
The problem of training classifiers only with target data arises in many applications where nontarget data are too costly, difficult to obtain, or not available at all. Several one-class classification methods have been presented to solve this problem, but most of the methods are highly sensitive to the presence of outliers in the target class. Ensemble methods have therefore been proposed as a powerful way to improve the classification performance of binary/multi-class learning algorithms by introducing diversity into classifiers. However, their application to one-class classification has been rather limited. In this paper, we present a new ensemble method based on a nonparametric weighted bagging strategy for one-class classification, to improve accuracy in the presence of outliers. While the standard bagging strategy assumes a uniform data distribution, the method we propose here estimates a probability density based on a forest structure of the data. This assumption allows the estimation of data distribution from the computation of simple univariate and bivariate kernel densities. Experiments using original and noisy versions of 20 different datasets show that bagging ensemble methods applied to different one-class classifiers outperform base one-class classification methods. Moreover, we show that, in noisy versions of the datasets, the nonparametric weighted bagging strategy we propose outperforms the classical bagging strategy in a statistically significant way.
Year
DOI
Venue
2013
10.1142/S0218001413500146
INTERNATIONAL JOURNAL OF PATTERN RECOGNITION AND ARTIFICIAL INTELLIGENCE
Keywords
Field
DocType
One-class classifier, ensemble methods, bagging, outliers
Kernel (linear algebra),Pattern recognition,Computer science,Outlier,Nonparametric statistics,Artificial intelligence,Univariate,Bivariate analysis,Probability density function,Ensemble learning,Machine learning,Binary number
Journal
Volume
Issue
ISSN
27
5
0218-0014
Citations 
PageRank 
References 
4
0.38
20
Authors
3
Name
Order
Citations
PageRank
Santi Seguí1859.11
Laura Igual226618.41
Jordi Vitrià373798.14