“…In WSNs, the problem of data storage and information discovery has been studied for many years. In a nutshell, data are stored in WSNs mainly based on the following three models: (1) data are stored among the sensor nodes in a distributed manner [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ]; (2) data are stored at the static Sink node/nodes intensively [ 29 , 30 , 31 , 32 , 33 ]; (3) data are collected and stored at some mobile elements [ 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ], such as mobile Sinks. For the first model, queries should be launched across the sensor nodes to search for and discover the needed information; for the second and third models, the needed information can be discovered directly at the static Sink node/nodes or the mobile elements.…”