Minima Possible Weights: A Homogenous Deep Ensemble Method for Cross-Subject Motor Imagery Classification

Motor Imagery (MI) systems in Brain-Computer Interface (BCI) research provide communication and control solutions for individuals with motor impairments, yet cross-subject classification remains challenging due to substantial inter-subject variability. In this study, we propose the Minima Possible W...

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Main Authors: Quang Pham Lam Dinh, Isao Nambu
Format: Article
Language:English
Published: IEEE 2025-01-01
Series:IEEE Access
Subjects:
Online Access:https://ieeexplore.ieee.org/document/10878971/
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author Quang Pham Lam Dinh
Isao Nambu
author_facet Quang Pham Lam Dinh
Isao Nambu
author_sort Quang Pham Lam Dinh
collection DOAJ
description Motor Imagery (MI) systems in Brain-Computer Interface (BCI) research provide communication and control solutions for individuals with motor impairments, yet cross-subject classification remains challenging due to substantial inter-subject variability. In this study, we propose the Minima Possible Weights (MPW) method, an unsupervised learning approach designed to enhance MI classification through ensemble deep learning. MPW aggregates predicted probabilities from multiple models and selects the class with the lowest associated weight for the final prediction. We evaluated MPW against various ensemble learning and test-time adaptation methods using two benchmark datasets: BCI Competition IV Dataset 2a and PhysionetMI. Our results indicate that MPW achieves cross-subject classification accuracy of up to 64.75% on BCI Competition IV Dataset 2a and 66.92% on PhysionetMI. Although the current performance is not yet sufficient for practical BCI applications, MPW shows potential in reducing calibration time and easing the burden of adapting models to new subjects.
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publishDate 2025-01-01
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spelling doaj-art-080e7b0acf5347afa443e33448ed1e192025-08-20T03:12:58ZengIEEEIEEE Access2169-35362025-01-0113291342914610.1109/ACCESS.2025.354016410878971Minima Possible Weights: A Homogenous Deep Ensemble Method for Cross-Subject Motor Imagery ClassificationQuang Pham Lam Dinh0https://orcid.org/0009-0008-9560-8823Isao Nambu1https://orcid.org/0000-0002-1705-6268Graduate School of Engineering, Nagaoka University of Technology, Niigata, JapanGraduate School of Engineering, Nagaoka University of Technology, Niigata, JapanMotor Imagery (MI) systems in Brain-Computer Interface (BCI) research provide communication and control solutions for individuals with motor impairments, yet cross-subject classification remains challenging due to substantial inter-subject variability. In this study, we propose the Minima Possible Weights (MPW) method, an unsupervised learning approach designed to enhance MI classification through ensemble deep learning. MPW aggregates predicted probabilities from multiple models and selects the class with the lowest associated weight for the final prediction. We evaluated MPW against various ensemble learning and test-time adaptation methods using two benchmark datasets: BCI Competition IV Dataset 2a and PhysionetMI. Our results indicate that MPW achieves cross-subject classification accuracy of up to 64.75% on BCI Competition IV Dataset 2a and 66.92% on PhysionetMI. Although the current performance is not yet sufficient for practical BCI applications, MPW shows potential in reducing calibration time and easing the burden of adapting models to new subjects.https://ieeexplore.ieee.org/document/10878971/Brain-computer interfacecross-subjectdeep ensemble learningmulti-class classificationmotor imageryunsupervised learning
spellingShingle Quang Pham Lam Dinh
Isao Nambu
Minima Possible Weights: A Homogenous Deep Ensemble Method for Cross-Subject Motor Imagery Classification
IEEE Access
Brain-computer interface
cross-subject
deep ensemble learning
multi-class classification
motor imagery
unsupervised learning
title Minima Possible Weights: A Homogenous Deep Ensemble Method for Cross-Subject Motor Imagery Classification
title_full Minima Possible Weights: A Homogenous Deep Ensemble Method for Cross-Subject Motor Imagery Classification
title_fullStr Minima Possible Weights: A Homogenous Deep Ensemble Method for Cross-Subject Motor Imagery Classification
title_full_unstemmed Minima Possible Weights: A Homogenous Deep Ensemble Method for Cross-Subject Motor Imagery Classification
title_short Minima Possible Weights: A Homogenous Deep Ensemble Method for Cross-Subject Motor Imagery Classification
title_sort minima possible weights a homogenous deep ensemble method for cross subject motor imagery classification
topic Brain-computer interface
cross-subject
deep ensemble learning
multi-class classification
motor imagery
unsupervised learning
url https://ieeexplore.ieee.org/document/10878971/
work_keys_str_mv AT quangphamlamdinh minimapossibleweightsahomogenousdeepensemblemethodforcrosssubjectmotorimageryclassification
AT isaonambu minimapossibleweightsahomogenousdeepensemblemethodforcrosssubjectmotorimageryclassification