Kuncheva, Ludmila I., Rodriguez, Juan J., Plumpton, Catrin O., Linden, David Edmund Johannes ORCID: https://orcid.org/0000-0002-5638-9292 and Johnston, Stephen J. 2010. Random subspace ensembles for fMRI classification. IEEE Transactions on Medical Imaging 29 (2) , pp. 531-542. 10.1109/TMI.2009.2037756 |
Abstract
Classification of brain images obtained through functional magnetic resonance imaging (fMRI) poses a serious challenge to pattern recognition and machine learning due to the extremely large feature-to-instance ratio. This calls for revision and adaptation of the current state-of-the-art classification methods. We investigate the suitability of the random subspace (RS) ensemble method for fMRI classification. RS samples from the original feature set and builds one (base) classifier on each subset. The ensemble assigns a class label by either majority voting or averaging of output probabilities. Looking for guidelines for setting the two parameters of the method-ensemble size and feature sample size-we introduce three criteria calculated through these parameters: usability of the selected feature sets, coverage of the set of ¿important¿ features, and feature set diversity. Optimized together, these criteria work toward producing accurate and diverse individual classifiers. RS was tested on three fMRI datasets from single-subject experiments: the Haxby data (Haxby, 2001.) and two datasets collected in-house. We found that RS with support vector machines (SVM) as the base classifier outperformed single classifiers as well as some of the most widely used classifier ensembles such as bagging, AdaBoost, random forest, and rotation forest. The closest rivals were the single SVM and bagging of SVM classifiers. We use kappa-error diagrams to understand the success of RS.
Item Type: | Article |
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Date Type: | Publication |
Status: | Published |
Schools: | Medicine Psychology MRC Centre for Neuropsychiatric Genetics and Genomics (CNGG) Neuroscience and Mental Health Research Institute (NMHRI) |
Subjects: | R Medicine > RC Internal medicine > RC0321 Neuroscience. Biological psychiatry. Neuropsychiatry R Medicine > RZ Other systems of medicine |
Uncontrolled Keywords: | Classifier ensembles , functional magnetic resonance imaging (fMRI) data analysis , multivariate methods , pattern recognition , random subspace (RS) method |
Publisher: | Institute of Electrical and Electronics Engineers |
ISSN: | 0278-0062 |
Last Modified: | 20 Oct 2022 08:40 |
URI: | https://orca.cardiff.ac.uk/id/eprint/29204 |
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