8 A Probabilistic Lifestyle-Based Trajectory Model for Social Strength Inference from Human Trajectory Data WAYNE XIN ZHAO, NINGNAN ZHOU, WENHUI ZHANG, JI-RONG WEN, and SHAN WANG, Renmin University of China EDWARD Y. CHANG, HTC Research & Innovation With the pervasiveness of location-based social networks, it becomes increasingly important to consider the social characteristics of locations shared among persons. Several studies have been proposed to infer social strength by using trajectory similarity. However, these studies have two major shortcomings. First, they rely on the explicit co-occurrence of check-in locations. In this situation, a user pair of two friends who seldom share common locations or a user pair of two strangers who heavily share common visited locations will receive an unreliable estimation of the real social strength between them. Second, these studies do not consider how the overall trajectory patterns of users change with the varying of living styles
