In Shift and In Variance: Assessing the Robustness of HAR Deep Learning Models Against Variability

Deep learning (DL)-based Human Activity Recognition (HAR) using wearable inertial measurement unit (IMU) sensors can revolutionize continuous health monitoring and early disease prediction. However, most DL HAR models are untested in their robustness to real-world variability, as they are trained on...

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Main Authors: Azhar Ali Khaked, Nobuyuki Oishi, Daniel Roggen, Paula Lago
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Sensors
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Online Access:https://www.mdpi.com/1424-8220/25/2/430
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author Azhar Ali Khaked
Nobuyuki Oishi
Daniel Roggen
Paula Lago
author_facet Azhar Ali Khaked
Nobuyuki Oishi
Daniel Roggen
Paula Lago
author_sort Azhar Ali Khaked
collection DOAJ
description Deep learning (DL)-based Human Activity Recognition (HAR) using wearable inertial measurement unit (IMU) sensors can revolutionize continuous health monitoring and early disease prediction. However, most DL HAR models are untested in their robustness to real-world variability, as they are trained on limited lab-controlled data. In this study, we isolated and analyzed the effects of the subject, device, position, and orientation variabilities on DL HAR models using the HARVAR and REALDISP datasets. The Maximum Mean Discrepancy (MMD) was used to quantify shifts in the data distribution caused by these variabilities, and the relationship between the distribution shifts and model performance was drawn. Our HARVAR results show that different types of variability significantly degraded the DL model performance, with an inverse relationship between the data distribution shifts and performance. The compounding effect of multiple variabilities studied using REALDISP further underscores the challenges of generalizing DL HAR models to real-world conditions. Analyzing these impacts highlights the need for more robust models that generalize effectively to real-world settings. The MMD proved valuable for explaining the performance drops, emphasizing its utility in evaluating distribution shifts in HAR data.
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spelling doaj-art-20ceb2e7b80e40fb8ba1efea7c57bee72025-01-24T13:48:54ZengMDPI AGSensors1424-82202025-01-0125243010.3390/s25020430In Shift and In Variance: Assessing the Robustness of HAR Deep Learning Models Against VariabilityAzhar Ali Khaked0Nobuyuki Oishi1Daniel Roggen2Paula Lago3Department of Electrical and Computer Engineering, Concordia University, Montreal, QC H3G 1M8, CanadaSchool of Engineering and Informatics, University of Sussex, Brighton BN1 9PS, UKSchool of Engineering and Informatics, University of Sussex, Brighton BN1 9PS, UKDepartment of Electrical and Computer Engineering, Concordia University, Montreal, QC H3G 1M8, CanadaDeep learning (DL)-based Human Activity Recognition (HAR) using wearable inertial measurement unit (IMU) sensors can revolutionize continuous health monitoring and early disease prediction. However, most DL HAR models are untested in their robustness to real-world variability, as they are trained on limited lab-controlled data. In this study, we isolated and analyzed the effects of the subject, device, position, and orientation variabilities on DL HAR models using the HARVAR and REALDISP datasets. The Maximum Mean Discrepancy (MMD) was used to quantify shifts in the data distribution caused by these variabilities, and the relationship between the distribution shifts and model performance was drawn. Our HARVAR results show that different types of variability significantly degraded the DL model performance, with an inverse relationship between the data distribution shifts and performance. The compounding effect of multiple variabilities studied using REALDISP further underscores the challenges of generalizing DL HAR models to real-world conditions. Analyzing these impacts highlights the need for more robust models that generalize effectively to real-world settings. The MMD proved valuable for explaining the performance drops, emphasizing its utility in evaluating distribution shifts in HAR data.https://www.mdpi.com/1424-8220/25/2/430human activity recognitionwearable sensorsdeep learningdistribution shiftreal world variabilitydata heterogeneity
spellingShingle Azhar Ali Khaked
Nobuyuki Oishi
Daniel Roggen
Paula Lago
In Shift and In Variance: Assessing the Robustness of HAR Deep Learning Models Against Variability
Sensors
human activity recognition
wearable sensors
deep learning
distribution shift
real world variability
data heterogeneity
title In Shift and In Variance: Assessing the Robustness of HAR Deep Learning Models Against Variability
title_full In Shift and In Variance: Assessing the Robustness of HAR Deep Learning Models Against Variability
title_fullStr In Shift and In Variance: Assessing the Robustness of HAR Deep Learning Models Against Variability
title_full_unstemmed In Shift and In Variance: Assessing the Robustness of HAR Deep Learning Models Against Variability
title_short In Shift and In Variance: Assessing the Robustness of HAR Deep Learning Models Against Variability
title_sort in shift and in variance assessing the robustness of har deep learning models against variability
topic human activity recognition
wearable sensors
deep learning
distribution shift
real world variability
data heterogeneity
url https://www.mdpi.com/1424-8220/25/2/430
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