Reusing training data with generative/discriminative hybrid model for practical acceleration-based activity recognition

This paper proposes a new daily activity recognition method that can learn an activity classification model with small quantities of training data by sharing training data among different activity classes. Many existing activity recognition studies employ a supervised machine learning approach and thus require an end user’s labeled training data, this approach places a large burden on the user. In this study, we assume that a user wears sensors (accelerometers) on several parts of the body such as the hands, waist, and thigh, and we attempt to share sensor data obtained from only selected accelerometers (e.g., only waist and thigh sensors) among two different activity classes based on a sensor data similarity measure. This approach permits us to correctly learn parameters of an activity classification model by using sufficient quantities of shared sensor data without adding new training data. We confirmed the effectiveness of our method by using 48 h of sensor data obtained from 20 participants, and achieved a good recognition accuracy.