G-CTRNN: A Trainable Low-Power Continuous-Time Neural Network for Human Activity Recognition in Healthcare Applications

Continuous-time Recurrent Neural Networks (CTRNNs) are well-suited for modeling temporal dynamics in low-power neuromorphic and analog computing systems, making them promising candidates for edge-based human activity recognition (HAR) in healthcare. However, training CTRNNs remains challenging due t...

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Main Authors: Abdallah Alzubi, David Lin, Johan Reimann, Fadi Alsaleem
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/15/13/7508
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author Abdallah Alzubi
David Lin
Johan Reimann
Fadi Alsaleem
author_facet Abdallah Alzubi
David Lin
Johan Reimann
Fadi Alsaleem
author_sort Abdallah Alzubi
collection DOAJ
description Continuous-time Recurrent Neural Networks (CTRNNs) are well-suited for modeling temporal dynamics in low-power neuromorphic and analog computing systems, making them promising candidates for edge-based human activity recognition (HAR) in healthcare. However, training CTRNNs remains challenging due to their continuous-time nature and the need to respect physical hardware constraints. In this work, we propose G-CTRNN, a novel gradient-based training framework for analog-friendly CTRNNs designed for embedded healthcare applications. Our method extends Backpropagation Through Time (BPTT) to continuous domains using TensorFlow’s automatic differentiation, while enforcing constraints on time constants and synaptic weights to ensure hardware compatibility. We validate G-CTRNN on the WISDM human activity dataset, which simulates realistic wearable sensor data for healthcare monitoring. Compared to conventional RNNs, G-CTRNN achieves superior classification accuracy with fewer parameters and greater stability—enabling continuous, real-time HAR on low-power platforms such as MEMS computing networks. The proposed framework provides a pathway toward on-device AI for remote patient monitoring, elderly care, and personalized healthcare in resource-constrained environments.
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spelling doaj-art-6a2945922e664a95828d35a5ff13bc162025-08-20T02:35:46ZengMDPI AGApplied Sciences2076-34172025-07-011513750810.3390/app15137508G-CTRNN: A Trainable Low-Power Continuous-Time Neural Network for Human Activity Recognition in Healthcare ApplicationsAbdallah Alzubi0David Lin1Johan Reimann2Fadi Alsaleem3Durham School of Architectural Engineering & Construction, College of Engineering, University of Nebraska-Lincoln, Omaha, NE 68182, USAGE Aerospace Research, Niskayuna, NY 12309, USAGE Aerospace Research, Niskayuna, NY 12309, USADurham School of Architectural Engineering & Construction, College of Engineering, University of Nebraska-Lincoln, Omaha, NE 68182, USAContinuous-time Recurrent Neural Networks (CTRNNs) are well-suited for modeling temporal dynamics in low-power neuromorphic and analog computing systems, making them promising candidates for edge-based human activity recognition (HAR) in healthcare. However, training CTRNNs remains challenging due to their continuous-time nature and the need to respect physical hardware constraints. In this work, we propose G-CTRNN, a novel gradient-based training framework for analog-friendly CTRNNs designed for embedded healthcare applications. Our method extends Backpropagation Through Time (BPTT) to continuous domains using TensorFlow’s automatic differentiation, while enforcing constraints on time constants and synaptic weights to ensure hardware compatibility. We validate G-CTRNN on the WISDM human activity dataset, which simulates realistic wearable sensor data for healthcare monitoring. Compared to conventional RNNs, G-CTRNN achieves superior classification accuracy with fewer parameters and greater stability—enabling continuous, real-time HAR on low-power platforms such as MEMS computing networks. The proposed framework provides a pathway toward on-device AI for remote patient monitoring, elderly care, and personalized healthcare in resource-constrained environments.https://www.mdpi.com/2076-3417/15/13/7508Human Activity Recognition (HAR)wearable healthcaresmart health monitoringedge computing in healthcareMEMS for healthcare AI
spellingShingle Abdallah Alzubi
David Lin
Johan Reimann
Fadi Alsaleem
G-CTRNN: A Trainable Low-Power Continuous-Time Neural Network for Human Activity Recognition in Healthcare Applications
Applied Sciences
Human Activity Recognition (HAR)
wearable healthcare
smart health monitoring
edge computing in healthcare
MEMS for healthcare AI
title G-CTRNN: A Trainable Low-Power Continuous-Time Neural Network for Human Activity Recognition in Healthcare Applications
title_full G-CTRNN: A Trainable Low-Power Continuous-Time Neural Network for Human Activity Recognition in Healthcare Applications
title_fullStr G-CTRNN: A Trainable Low-Power Continuous-Time Neural Network for Human Activity Recognition in Healthcare Applications
title_full_unstemmed G-CTRNN: A Trainable Low-Power Continuous-Time Neural Network for Human Activity Recognition in Healthcare Applications
title_short G-CTRNN: A Trainable Low-Power Continuous-Time Neural Network for Human Activity Recognition in Healthcare Applications
title_sort g ctrnn a trainable low power continuous time neural network for human activity recognition in healthcare applications
topic Human Activity Recognition (HAR)
wearable healthcare
smart health monitoring
edge computing in healthcare
MEMS for healthcare AI
url https://www.mdpi.com/2076-3417/15/13/7508
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AT davidlin gctrnnatrainablelowpowercontinuoustimeneuralnetworkforhumanactivityrecognitioninhealthcareapplications
AT johanreimann gctrnnatrainablelowpowercontinuoustimeneuralnetworkforhumanactivityrecognitioninhealthcareapplications
AT fadialsaleem gctrnnatrainablelowpowercontinuoustimeneuralnetworkforhumanactivityrecognitioninhealthcareapplications