3 research outputs found
A 'one-size-fits-most' walking recognition method for smartphones, smartwatches, and wearable accelerometers
The ubiquity of personal digital devices offers unprecedented opportunities
to study human behavior. Current state-of-the-art methods quantify physical
activity using 'activity counts,' a measure which overlooks specific types of
physical activities. We proposed a walking recognition method for sub-second
tri-axial accelerometer data, in which activity classification is based on the
inherent features of walking: intensity, periodicity, and duration. We
validated our method against 20 publicly available, annotated datasets on
walking activity data collected at various body locations (thigh, waist, chest,
arm, wrist). We demonstrated that our method can estimate walking periods with
high sensitivity and specificity: average sensitivity ranged between 0.92 and
0.97 across various body locations, and average specificity for common daily
activities was typically above 0.95. We also assessed the method's algorithmic
fairness to demographic and anthropometric variables and measurement contexts
(body location, environment). Finally, we have released our method as
open-source software in MATLAB and Python.Comment: 39 pages, 4 figures (incl. 1 supplementary), and 5 tables (incl. 2
supplementary
Mobile User Indoor-Outdoor Detection through Physical Daily Activities
An automatic, fast, and accurate switching method between Global Positioning System and indoor positioning systems is crucial to achieve current user positioning, which is essential information for a variety of services installed on smart devices, e.g., location-based services (LBS), healthcare monitoring components, and seamless indoor/outdoor navigation and localization (SNAL). In this study, we proposed an approach to accurately detect the indoor/outdoor environment according to six different daily activities of users including walk, skip, jog, stay, climbing stairs up and down. We select a number of features for each activity and then apply ensemble learning methods such as Random Forest, and AdaBoost to classify the environment types. Extensive model evaluations and feature analysis indicate that the system can achieve a high detection rate with good adaptation for environment recognition. Empirical evaluation of the proposed method has been verified on the HASC-2016 public dataset, and results show 99% accuracy to detect environment types. The proposed method relies only on the daily life activities data and does not need any external facilities such as the signal cell tower or Wi-Fi access points. This implies the applicability of the proposed method for the upper layer applications