Introduction
With the prevalence of rich-sensor equipped smartphones in recent years, mobile crowdsensing (MCS) has become a promising paradigm to facilitate urban sensing applications, such as environment monitoring, traffic congestion detection, hotspot identification, and public information sharing [1]–[4]. Traditional urban sensing applications rely on the expensive specialized sensing infrastructure (e.g., air quality monitoring stations); however, only utilizing the specialized sensing infrastructure to enable urban sensing applications has some pitfalls such as high deployment/maintenance cost and lack of reusability across multiple applications, which hinder the rapid growth of heterogeneous urban sensing applications to a large scale. Complementary to the traditional sensing paradigm, MCS helps to achieve the urban sensing goal by leveraging the mobility of mobile users, the sensors embedded in mobile phones, and the existing wireless infrastructure to sense and collect environment data, making it possible to inexpensively sense various urban data in regions that are not covered by the specialized sensing infrastructure.