Semantic Labeling of User Location Context Based on Phone Usage Features.

In mobile phones, the awareness of the user's context allows services better tailored to the user's needs. We propose a machine learning based method for semantic labeling that utilizes phone usage features to detect the user's home, work, and other visited places. For place detection, we compare seven different classification methods. We organize the phone usage data based on periods of uninterrupted time that the user has been in a certain place. We consider three approaches to represent this data: visits, places, and cumulative samples. Our main contribution is semantic place labeling using a small set of privacy-preserving features and novel data representations suitable for resource constrained mobile devices. The contributions include (1) introduction of novel data representations including accumulation and averaging of the usage, (2) analysis of the effect of the data accumulation time on the accuracy of the place classification, (3) analysis of the confidence on the classification outcome, and (4) identification of the most relevant features obtained through feature selection methods. With a small set of privacy-preserving features and our data representations, we detect the user's home and work with probability of 90% or better, and in 3-class problem the overall classification accuracy was 89% or better.