A distributed top-k query method for IoT data

Abstract

The invention discloses a distributed Top-k query method oriented to Internet of things data. The distributed Top-k query method comprises the following steps: (1) establishing an optimal query tree, specifically comprising the following three processes, namely selecting network backbone nodes, selecting connecting nodes, and acting each node queried in each turn as a root node in turn according to an ID (Identification) number; (2) carrying out Top-k query on the basis of the optimal query tree, specifically comprising the three following processes, namely query initialization, data update value sending, and top-k query of sink nodes. According to the distributed Top-k query method, the node degrees, the self energy and communication overhead of adjacent nodes are sufficiently considered when the optimal query tree is established, and the nodes having low energy cost are selected as dominate nodes, so that the energy consumption of the nodes is effectively balanced, the problem that nodes near a root node undergo premature death only brought in a traditional query tree is further solved, and the life cycle of the Internet of things is greatly prolonged; in addition, sending of invalid update values in each turn is restricted by setting filter values in a query algorithm, and thus the average query energy consumption in each turn is effectively reduced.

Description

technical field [0001] The invention relates to Internet of Things data processing technology, in particular to a distributed Top-k query method for Internet of Things data. Background technique [0002] The Internet of Things is a network that connects items to the network through various sensor devices, performs information exchange and communication, and realizes intelligent identification, positioning, tracking, monitoring and management. As an important part of the sensing layer of the Internet of Things, sensor nodes play an important role in the process of information acquisition and processing. [0003] Top-k query, as an important content of the Internet of Things query application, has been widely used in many fields, such as environmental pollution monitoring, animal protection, and target tracking; users can query the top k largest (or smallest) in the monitoring area according to their own needs. ) sensing values, such as temperature, pollution index, etc., so ...

AI Technical Summary

Problems solved by technology

For example, the FILA algorithm proposed by Wu et al. based on the shortest path tree SPT, SPT uses the sink as the root node, and other nodes have the shortest path to the sink, but the FILA algorithm ignores the energy consumption of each node receiving detection information, which is inconsistent with the actual situation. One round of query, if the node perception value does not exceed the filtering range, no updated value will be sent to the sink, so the query result is inaccurate

[0005] In order to meet the query accuracy, Balijeet et al. proposed a query algorithm EXTOK based on the dominating set tree DST. This algorithm sets a filtering threshold for each node to decide whether to send an update value to the sink in the next round, but its DST construction mainly selects neighbors. The node with many nodes acts as the dominant node, without considering the energy of the node itself and the communication cost with neighboring nodes. When the number of queries and the value of k increase, there will be problems of uneven energy consumption and premature death of nodes near the sink. In the EXTOK algorithm, TM- The node needs to send updated values ​​to the sink every round, resulting in invalid sending of some values

[0006] Tang et al. proposed a novel top-k query algorithm based on the hierarchical index tree, but there are also problems such as premature death when the head node is selected without considering its own energy.

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