Investigating Inter-Subject and Inter-Activity Variations in Activity Recognition Using Wearable Motion Sensors

Autor: Billur Barshan, Aras Yurtman
Rok vydání: 2015
Předmět:
Technology
Similarity (geometry)
General Computer Science
Activity recognition and classification
Computer science
Feature vector
Feature reduction
TIME-SERIES
Wearable computer
Inertial sensors
02 engineering and technology
Variation (game tree)
Machine learning
computer.software_genre
Distance measures
Set (abstract data type)
Activity recognition
Consistency (database systems)
Computer Science
Theory & Methods

0202 electrical engineering
electronic engineering
information engineering

Inter-activity variation
Dynamic time warping
Computer Science
Hardware & Architecture

Science & Technology
Computer Science
Information Systems

business.industry
020206 networking & telecommunications
Motion sensors
Computer Science
Software Engineering

Gyroscope
Magnetometers
Inter-subject variation
Wearable sensing
CAPTURE
Accelerometer
PHYSICAL-ACTIVITY
Computer Science
magnetometer
Feature extraction
020201 artificial intelligence & image processing
Artificial intelligence
business
Motion capture
computer
Zdroj: Computer Journal
ISSN: 1460-2067
0010-4620
DOI: 10.1093/comjnl/bxv093
Popis: This work investigates inter-subject and inter-activity variability of a given activity dataset and provides some new definitions to quantify such variability. The definitions are sufficiently general and can be applied to a broad class of datasets that involve time sequences or features acquired using wearable sensors. The study is motivated by contradictory statements in the literature on the need for user-specific training in activity recognition. We employ our publicly available dataset that contains 19 daily and sports activities acquired from eight participants who wear five motion sensor units each. We pre-process recorded activity time sequences in three different ways and employ absolute, Euclidean and dynamic time warping distance measures to quantify the similarity of the recorded signal patterns. We define and calculate the average inter-subject and inter-activity distances with various methods based on the raw and pre-processed time-domain data as well as on the raw and pre-processed feature vectors. These definitions allow us to identify the subject who performs the activities in the most representative way and pinpoint the activities that show more variation among the subjects. We observe that the type of pre-processing used affects the results of the comparisons but that the different distance measures do not alter the comparison results as much. We check the consistency of our analysis and results by highlighting some of our activity recognition rates based on an exhaustive set of sensor unit, sensor type and subject combinations. We expect the results to be useful for dynamic sensor unit/type selection, for deciding whether to perform user-specific training and for designing more effective classifiers in activity recognition.
Databáze: OpenAIRE