An Algorithm for On-Sensor Agnostic Detection of Changes in Human Activity for Ultra-Low-Power Applications

Fuente: arXiv
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Main Authors: Rimoldi, Sara, De Vecchi, Arianna, Shalby, Hazem Hesham Yousef, Villa, Federica
Format: Preprint
Published: 2026
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author Rimoldi, Sara
De Vecchi, Arianna
Shalby, Hazem Hesham Yousef
Villa, Federica
author_facet Rimoldi, Sara
De Vecchi, Arianna
Shalby, Hazem Hesham Yousef
Villa, Federica
contents Wearable devices running Human Activity Recognition(HAR) on Inertial Measurement Units~(IMUs) waste energy by performing continuous classification for each window, even during long periods of unchanged activity. We address this with a lightweight change-detection gate: a non-parametric algorithm based on dynamic template matching that runs continuously at only approximately 16kFLOPs per step, requires no offline training, and does not need prior definition of target activity classes. The gate invokes the full HAR network only when it detects an activity change, reducing the computational load by over 67% in realistic monitoring settings. The algorithm is evaluated on smart glasses, smartwatch, and smartphone data, requiring only a brief device-specific calibration phase. The gate achieves 98% sensitivity on UCA-EHAR, ensuring no genuine activity transition is missed, while 75% specificity keeps unnecessary HAR invocations low. Results on WISDM are 97% sensitivity and 76% specificity, demonstrating robustness and flexibility to various settings.
format Preprint
id arxiv_https___arxiv_org_abs_2605_00870
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle An Algorithm for On-Sensor Agnostic Detection of Changes in Human Activity for Ultra-Low-Power Applications
Rimoldi, Sara
De Vecchi, Arianna
Shalby, Hazem Hesham Yousef
Villa, Federica
Signal Processing
Artificial Intelligence
Machine Learning
Wearable devices running Human Activity Recognition(HAR) on Inertial Measurement Units~(IMUs) waste energy by performing continuous classification for each window, even during long periods of unchanged activity. We address this with a lightweight change-detection gate: a non-parametric algorithm based on dynamic template matching that runs continuously at only approximately 16kFLOPs per step, requires no offline training, and does not need prior definition of target activity classes. The gate invokes the full HAR network only when it detects an activity change, reducing the computational load by over 67% in realistic monitoring settings. The algorithm is evaluated on smart glasses, smartwatch, and smartphone data, requiring only a brief device-specific calibration phase. The gate achieves 98% sensitivity on UCA-EHAR, ensuring no genuine activity transition is missed, while 75% specificity keeps unnecessary HAR invocations low. Results on WISDM are 97% sensitivity and 76% specificity, demonstrating robustness and flexibility to various settings.
title An Algorithm for On-Sensor Agnostic Detection of Changes in Human Activity for Ultra-Low-Power Applications
topic Signal Processing
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2605.00870