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Abstract This work details the partially observable markov decision process (POMDP) and the point-based value iteration (PBVI) algorithms for use in multisensor systems, specifically, a sensor system capable of heart rate (HR) estimation through wearable photoplethysmography (PPG) and accelerometer signals. PPG sensors are highly susceptible to motion artifact (MA); however, current methods focus more on overall MA filters, rather than action specific filtering. An end-to-end embedded human activity recognition (HAR) System is developed to represent the observation uncertainty, and two action specific PPG MA reducing filters are proposed as actions. PBVI allows optimal action decision-making based on an uncertain observation, effectively balancing correct action choice and sensor system cost. Two central systems are proposed to accompany these algorithms, one for unlimited observation access and one for limited observation access. Through simulation, it can be shown that the limited observation system performs optimally when sensor cost is negligible, while limited observation access performs optimally when a negative reward for sensor use is considered. The final general framework for POMDP and PBVI was applied to a specific HR estimation example. This work can be expanded on and used as a basis for future work on similar multisensor system.
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An Accurate Non-accelerometer-based PPG Motion Artifact Removal Technique using CycleGAN
A photoplethysmography (PPG) is an uncomplicated and inexpensive optical technique widely used in the healthcare domain to extract valuable health-related information, e.g., heart rate variability, blood pressure, and respiration rate. PPG signals can easily be collected continuously and remotely using portable wearable devices. However, these measuring devices are vulnerable to motion artifacts caused by daily life activities. The most common ways to eliminate motion artifacts use extra accelerometer sensors, which suffer from two limitations: i) high power consumption and ii) the need to integrate an accelerometer sensor in a wearable device (which is not required in certain wearables). This paper proposes a low-power non-accelerometer-based PPG motion artifacts removal method outperforming the accuracy of the existing methods. We use Cycle Generative Adversarial Network to reconstruct clean PPG signals from noisy PPG signals. Our novel machine-learning-based technique achieves 9.5 times improvement in motion artifact removal compared to the state-of-the-art without using extra sensors such as an accelerometer, which leads to 45% improvement in energy efficiency.
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- Award ID(s):
- 2028782
- PAR ID:
- 10359654
- Date Published:
- Journal Name:
- ACM Transactions on Computing for Healthcare
- ISSN:
- 2691-1957
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1145/3563949
