A two-layer and multi-strategy framework for human activity recognition using smartphone

Human Activity Recognition (HAR) is widely used in many applications and HAR using smartphone only has been proved to be effective, flexible and unobtrusive for activity recognition. In this paper, a two-layer and multi-strategy HAR framework is proposed to overcome the major challenge of HAR using smartphone only, i.e., the variation in orientation and position of the device. In the first layer, the activities are classified into different groups with high accuracy and for each group in the second layer, the appropriate strategy is designed according to the characteristics of the group to improve the recognition performance. For static activity group, the transitional activities are introduced to help classifying the activities indirectly. For dynamic activity group sensitive to the position variation of the smartphone, a position-assisted strategy is proposed to alleviate the influence of position variation. The simulation results demonstrate the effectiveness of the proposed two-layer multi-strategy HAR framework.