“…In summary, the merits of fog computing mainly involve (a) quick response to delay-sensitive requirements, (b) data aggregation from heterogeneous devices, (c) data protection and security for sensitive data applications due to avoiding to send data to the cloud, and (d) avoiding unnecessary communication, see [1] for more details. Recently, some preliminary results on fog computing for sensor networks are published in the literature, such as edge node reconfiguration [51,60], the choice of the sensing routing [70], as well as network architecture managements [54,62]. It should be stressed that fog computing, being in its infancy stage, exposes several challenges that need to be further addressed, such as fog-cloud collaboration, service scalability, fog scalability, storage security and communication security, tradeoff between energy consumption and communication efficiency and so forth.…”