On the Role of Training Data for SVM-Based Microwave Brain Stroke Detection and Classification

The aim of this work was to test microwave brain stroke detection and classification using support vector machines (SVMs). We tested how the nature and variability of training data and system parameters impact the achieved classification accuracy. Using experimentally verified numerical models, a la...

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Main Authors: Tomas Pokorny, Jan Vrba, Ondrej Fiser, David Vrba, Tomas Drizdal, Marek Novak, Luca Tosi, Alessandro Polo, Marco Salucci
Format: Article
Language:English
Published: MDPI AG 2023-02-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/23/4/2031
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author Tomas Pokorny
Jan Vrba
Ondrej Fiser
David Vrba
Tomas Drizdal
Marek Novak
Luca Tosi
Alessandro Polo
Marco Salucci
author_facet Tomas Pokorny
Jan Vrba
Ondrej Fiser
David Vrba
Tomas Drizdal
Marek Novak
Luca Tosi
Alessandro Polo
Marco Salucci
author_sort Tomas Pokorny
collection DOAJ
description The aim of this work was to test microwave brain stroke detection and classification using support vector machines (SVMs). We tested how the nature and variability of training data and system parameters impact the achieved classification accuracy. Using experimentally verified numerical models, a large database of synthetic training and test data was created. The models consist of an antenna array surrounding reconfigurable geometrically and dielectrically realistic human head phantoms with virtually inserted strokes of arbitrary size, and different dielectric parameters in different positions. The generated synthetic data sets were used to test four different hypotheses, regarding the appropriate parameters of the training dataset, the appropriate frequency range and the number of frequency points, as well as the level of subject variability to reach the highest SVM classification accuracy. The results indicate that the SVM algorithm is able to detect the presence of the stroke and classify it (i.e., ischemic or hemorrhagic) even when trained with single-frequency data. Moreover, it is shown that data of subjects with smaller strokes appear to be the most suitable for training accurate SVM predictors with high generalization capabilities. Finally, the datasets created for this study are made available to the community for testing and developing their own algorithms.
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spelling doaj.art-7f4178e9675442adab2b1ea629bc9f9a2023-11-16T23:09:25ZengMDPI AGSensors1424-82202023-02-01234203110.3390/s23042031On the Role of Training Data for SVM-Based Microwave Brain Stroke Detection and ClassificationTomas Pokorny0Jan Vrba1Ondrej Fiser2David Vrba3Tomas Drizdal4Marek Novak5Luca Tosi6Alessandro Polo7Marco Salucci8Department of Biomedical Technology, Faculty of Biomedical Engineering, Czech Technical University in Prague, 166 00 Prague, Czech RepublicDepartment of Biomedical Technology, Faculty of Biomedical Engineering, Czech Technical University in Prague, 166 00 Prague, Czech RepublicDepartment of Biomedical Technology, Faculty of Biomedical Engineering, Czech Technical University in Prague, 166 00 Prague, Czech RepublicDepartment of Biomedical Technology, Faculty of Biomedical Engineering, Czech Technical University in Prague, 166 00 Prague, Czech RepublicDepartment of Biomedical Technology, Faculty of Biomedical Engineering, Czech Technical University in Prague, 166 00 Prague, Czech RepublicDepartment of Biomedical Technology, Faculty of Biomedical Engineering, Czech Technical University in Prague, 166 00 Prague, Czech RepublicELEDIA Research Center (ELEDIA@UniTN—University of Trento), DICAM—Department of Civil, Environmental, and Mechanical Engineering, Via Mesiano 77, 38123 Trento, ItalyELEDIA Research Center (ELEDIA@UniTN—University of Trento), DICAM—Department of Civil, Environmental, and Mechanical Engineering, Via Mesiano 77, 38123 Trento, ItalyELEDIA Research Center (ELEDIA@UniTN—University of Trento), DICAM—Department of Civil, Environmental, and Mechanical Engineering, Via Mesiano 77, 38123 Trento, ItalyThe aim of this work was to test microwave brain stroke detection and classification using support vector machines (SVMs). We tested how the nature and variability of training data and system parameters impact the achieved classification accuracy. Using experimentally verified numerical models, a large database of synthetic training and test data was created. The models consist of an antenna array surrounding reconfigurable geometrically and dielectrically realistic human head phantoms with virtually inserted strokes of arbitrary size, and different dielectric parameters in different positions. The generated synthetic data sets were used to test four different hypotheses, regarding the appropriate parameters of the training dataset, the appropriate frequency range and the number of frequency points, as well as the level of subject variability to reach the highest SVM classification accuracy. The results indicate that the SVM algorithm is able to detect the presence of the stroke and classify it (i.e., ischemic or hemorrhagic) even when trained with single-frequency data. Moreover, it is shown that data of subjects with smaller strokes appear to be the most suitable for training accurate SVM predictors with high generalization capabilities. Finally, the datasets created for this study are made available to the community for testing and developing their own algorithms.https://www.mdpi.com/1424-8220/23/4/2031SVMbrain strokemicrowave devicesnumerical model
spellingShingle Tomas Pokorny
Jan Vrba
Ondrej Fiser
David Vrba
Tomas Drizdal
Marek Novak
Luca Tosi
Alessandro Polo
Marco Salucci
On the Role of Training Data for SVM-Based Microwave Brain Stroke Detection and Classification
Sensors
SVM
brain stroke
microwave devices
numerical model
title On the Role of Training Data for SVM-Based Microwave Brain Stroke Detection and Classification
title_full On the Role of Training Data for SVM-Based Microwave Brain Stroke Detection and Classification
title_fullStr On the Role of Training Data for SVM-Based Microwave Brain Stroke Detection and Classification
title_full_unstemmed On the Role of Training Data for SVM-Based Microwave Brain Stroke Detection and Classification
title_short On the Role of Training Data for SVM-Based Microwave Brain Stroke Detection and Classification
title_sort on the role of training data for svm based microwave brain stroke detection and classification
topic SVM
brain stroke
microwave devices
numerical model
url https://www.mdpi.com/1424-8220/23/4/2031
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