“…Traditional techniques have studied the query processing in WSNs from various aspects, including in-network query processing [ 18 ], aggregated query processing [ 19 ], compressed data aggregation [ 20 ], spatial correlation data aggregation [ 21 ], range query processing [ 22 ], opportunistic sampling-based query processing [ 23 ], snapshot and continuous data aggregation [ 17 , 24 ], real-time query processing [ 25 ], multiple dimensional or attributes query optimization [ 26 – 28 ], cooperative caching-based query processing [ 29 , 30 ], etc. Generally, these techniques are mostly exploring the one-shot query scheduling, where one single attribute is interested, whereas few efforts study periodic, aggregated and multi-attribute query processing [ 31 ].…”