Authors:
Toshiki Iso
and
Kenichi Yamazaki
Affiliation:
Network Laboratories, NTT DoCoMo, Inc., Japan
Keyword(s):
Context extraction, sensors, cell phone, wavelet packet, Kohonen self-organizing map, ubiquitous service, accelerometer.
Related
Ontology
Subjects/Areas/Topics:
Design and Implementation of Signal Processing Systems
;
Multidimensional Signal Processing
;
Multimedia
;
Multimedia Signal Processing
;
Multimedia Systems and Applications
;
Telecommunications
Abstract:
To realize ubiquitous services such as presence services and health care services, we propose an algorithm to extract ”personal user context” such as user’s behavior; it processes information gathered by a three-axis accelerometer mounted on a cell phone. Our algorithm has two main functions; one is to extract feature vectors by analyzing sensor data in detail by wavelet packet decomposition. The other is to flexibly cluster personal user context by combining a self-organizing algorithm with Bayesian theory. A prototype that implements the algorithm is constructed. Experiments on the prototype show that the algorithm can identify personal user contexts such as walking, running, going up/down stairs, and walking fast with an accuracy of about 88[%].