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The moving k nearest neighbor query, which computes one’s k nearest neighbor set and maintains it while at move, is gaining importance due to the prevalent use of smart mobile devices such as smart phones. Safe region is a popular technique in processing the moving k nearest neighbor query. It is a region where the movement of the query object does not(More)
In recent years, there has been a growing need for location-based services (LBS), ranging from resource tracking to personal life assistance. The Moving k Nearest Neighbor (MkNN) query is a main problem in the LBS area, which retrieves the top k nearest neighbors while the query consumer moves. Considerable attention is attracted to this query type and a(More)
In recent years, there has been a growing need for complex event processing (CEP), ranging from supply chain management to security monitoring. In many scenarios events are generated in different sources but arrive at the central server out of order, due to the differences of network latencies. Most state-of-the-art techniques process out-of-order events by(More)
The moving $$k$$ k nearest neighbor (MkNN) query has been studied extensively. Most of the studies assume no obstacle in the space. However, obstacles like rivers, buildings and private properties commonly exist in the space, and one may need to go around the obstacles to reach his/her nearest neighbors. In this paper, we study the moving kNN query in(More)
We revisit the moving k nearest neighbor (MkNN) query, which computes one's k nearest neighbor set and maintains it while at move. Existing MkNN algorithms are mostly safe region based, which lack efficiency due to either computing small safe regions with a high recomputation frequency or computing larger safe regions but with a high cost for each(More)
With extensive applications of wireless sensor networks (WSNs), a WSN system with single function such as sea-monitoring and accident succor is expected to supply much more abilities for effective periodic queries or ad hoc queries, because some applications require real-time queries since the results should be returned before deadlines. Meanwhile,(More)
For mission-critical applications such as emergency monitoring over wireless sensor networks, query deadline must be satisfied. Otherwise, the query results would be useless. Thus, it is better to query the nodes as many as possible within the deadline. On the other hand, the energy consumption should be saved to prolong the life of the network. For this(More)