Class imbalance ensemble learning based on the margin theory.

Feng, Wei; Huang, Wenjiang; Ren, Jinchang

Abstract

The proportion of instances belonging to each class in a data-set plays an important role in machine learning. However, the real world data often suffer from class imbalance. Dealing with multi-class tasks with different misclassification costs of classes is harder than dealing with two-class ones. Undersampling and oversampling are two of the most popular data preprocessing techniques dealing with imbalanced data-sets. Ensemble classifiers have been shown to be more effective than data sampling techniques to enhance the classification performance of imbalanced data. Moreover, the combination of ensemble learning with sampling methods to tackle the class imbalance problem has led to several proposals in the literature, with positive results. The ensemble margin is a fundamental concept in ensemble learning. Several studies have shown that the generalization performance of an ensemble classifier is related to the distribution of its margins on the training examples. In this paper, we propose a novel ensemble margin based algorithm, which handles imbalanced classification by employing more low margin examples which are more informative than high margin samples. This algorithm combines ensemble learning with undersampling, but instead of balancing classes randomly such as UnderBagging, our method pays attention to constructing higher quality balanced sets for each base classifier. In order to demonstrate the effectiveness of the proposed method in handling class imbalanced data, UnderBagging and SMOTEBagging are used in a comparative analysis. In addition, we also compare the performances of different ensemble margin definitions, including both supervised and unsupervised margins, in class imbalance learning.

Citation

FENG, W., HUANG, W. and REN, J. 2018. Class imbalance ensemble learning based on the margin theory. Applied sciences [online], 8(5), article number 815. Available from: https://doi.org/10.3390/app8050815

• Journal Article Type: Article
• Acceptance Date: May 14, 2018
• Online Publication Date: May 18, 2018
• Publication Date: May 31, 2018
• Deposit Date: Jul 17, 2024
• Publicly Available Date: Jul 17, 2024
• Journal: Applied sciences.
• Electronic ISSN: 2076-3417
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• Volume: 8
• Issue: 5
• Article Number: 815
• DOI: https://doi.org/10.3390/app8050815
• Keywords: Classification; Ensemble margins; Imbalance learning; Ensemble learning; Multi-class
• Public URL: https://rgu-repository.worktribe.com/output/2059022