Limited-memory warping LCSS for real-time low-power pattern recognition in wireless nodes

Roggen, Daniel, Ponce Cuspinera, Luis, Pombo, Guilherme, Ali, Falah and Nguyen-Dinh, Long-Van (2014) Limited-memory warping LCSS for real-time low-power pattern recognition in wireless nodes. In: 12th European Conference on Wireless Sensor Networks, 9-11 February 2015, Porto, Portugal.

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We present and evaluate a microcontroller-optimized limited-memory implementation of a Warping Longest Common Subsequence algorithm (WarpingLCSS). It permits to spot patterns within noisy sensor data in real-time in resource constrained sensor nodes. It allows variability in the sensed system dynamics through warping; it uses only integer operations; it can be applied to various sensor modalities; and it is suitable for embedded training to recognize new patterns. We illustrate the method on 3 applications from wearable sensing and activity recognition using 3 sensor modalities: spotting the QRS complex in ECG, recognizing gestures in everyday life, and analyzing beach volleyball. We implemented the system on a low-power 8-bit AVR wireless node and a 32-bit ARM Cortex M4 microcontroller. Up to 67 or 140 10-second gestures can be recognized simultaneously in real-time from a 10Hz motion sensor on the AVR and M4 using 8mW and 10mW respectively. A single gesture spotter uses as few as 135μW on the AVR. The method allows low data rate distributed in-network recognition and we show a 100 fold data rate reduction in a complex activity recognition scenario. The versatility and low complexity of the method makes it well suited as a generic pattern recognition method and could be implemented as part of sensor front-ends.

Item Type: Conference or Workshop Item (Paper)
Additional Information: Published in: Wireless sensor networks (Lecture notes in computer science, Volume 8965, 2015, pages 151-167)
Keywords: Activity Recognition, Wearable Sensing, Streaming pattern spotting, Distributed Recognition, Machine Learning, Event Processing
Schools and Departments: School of Engineering and Informatics > Engineering and Design
Subjects: T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK7800 Electronics > TK7885 Computer engineering. Computer hardware
Depositing User: Daniel Roggen
Date Deposited: 04 Feb 2015 13:49
Last Modified: 05 Feb 2015 11:20

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