Title
Two-stage Human Activity Recognition on Microcontrollers with Decision Trees and CNNs
Abstract
Human Activity Recognition (HAR) has become an increasingly popular task for embedded devices such as smartwatches. Most HAR systems for ultra-low power devices are based on classic Machine Learning (ML) models, whereas Deep Learning (DL), although reaching state-of-the-art accuracy, is less popular due to its high energy consumption, which poses a significant challenge for battery-operated and resource-constrained devices. In this work, we bridge the gap between on-device HAR and DL thanks to a hierarchical architecture composed of a decision tree (DT) and a one dimensional Convolutional Neural Network (ID CNN). The two classifiers operate in a cascaded fashion on two different sub-tasks: the DT classifies only the easiest activities, while the CNN deals with more complex ones. With experiments on a state-of-the-art dataset and targeting a single-core RISC-V MCU, we show that this approach allows to save up to 67.7% energy w.r.t. a “stand-alone” DL architecture at iso-accuracy. Additionally, the two-stage system either introduces a negligible memory overhead (up to 200 B) or on the contrary, reduces the total memory occupation.
Year
DOI
Venue
2022
10.1109/PRIME55000.2022.9816745
2022 17th Conference on Ph.D Research in Microelectronics and Electronics (PRIME)
Keywords
DocType
ISBN
Machine Learning,Adaptive Inference,Microcontrollers,Energy Efficiency
Conference
978-1-6654-6701-8
Citations 
PageRank 
References 
0
0.34
7
Authors
3
Name
Order
Citations
PageRank
Francesco Daghero141.86
Daniele Jahier Pagliari200.68
Massimo Poncino300.34