Minimizing inter-subject variability in fNIRS-based brain–computer interfaces via multiple-kernel support vector learning

Abibullaev, Berdakh; An, Jinung; Jin, Sang-Hyeon; Lee, Seung Hyun; Moon, Jeon Il; Berdakh, Abibullaev

Minimizing inter-subject variability in fNIRS-based brain–computer interfaces via multiple-kernel support vector learning

Date

2013-12-01

Authors

Abibullaev, Berdakh

Berdakh, Abibullaev

An, Jinung

Jin, Sang-Hyeon

Lee, Seung Hyun

Moon, Jeon Il

Publisher

Medical Engineering & Physics

Abstract

Abstract Brain signal variation across different subjects and sessions significantly impairs the accuracy of most brain–computer interface (BCI) systems. Herein, we present a classification algorithm that minimizes such variation, using linear programming support-vector machines (LP-SVM) and their extension to multiple kernel learning methods. The minimization is based on the decision boundaries formed in classifiers’ feature spaces and their relation to BCI variation. Specifically, we estimate subject/session-invariant features in the reproducing kernel Hilbert spaces (RKHS) induced with Gaussian kernels. The idea is to construct multiple subject/session-dependent RKHS and to perform classification with LP-SVMs. To evaluate the performance of the algorithm, we applied it to oxy-hemoglobin data sets acquired from eight sessions and seven subjects as they performed two different mental tasks. Results show that our classifiers maintain good performance when applied to random patterns across varying sessions/subjects.

Keywords

Brain–computer interfaces, Functional near-infrared spectroscopy, Inter-subject variability, Support vector machines, RKHS, Multiple kernel learning

Citation

Berdakh Abibullaev, Jinung An, Sang-Hyeon Jin, Seung Hyun Lee, Jeon Il Moon, Minimizing inter-subject variability in fNIRS-based brain–computer interfaces via multiple-kernel support vector learning, In Medical Engineering & Physics, Volume 35, Issue 12, 2013, Pages 1811-1818