Mobile object continuous k-nearest neighbor (CKNN) query method based on road based road networks tree (RRN-Tree) in road network
A technology for moving objects and road networks, applied in the field of data query, can solve problems such as low query efficiency, inability to solve complex road network nearest neighbor query problems, and inability to reflect the steering relationship of moving objects, so as to achieve the effect of performance improvement
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[0044] Specific implementation mode 1: the following combination Figure 1 to Figure 12 To explain this embodiment, the CKNN query method of moving objects based on RRN-Tree in the road network described in this embodiment, the implementation steps of the query method are:
[0045] Step 1: First, define the road network G, route r, road section seg, intersection j, moving object o and KNN monitoring area respectively;
[0046] The road network G is a two-tuple G=(R, J), where R is a set of routes in the road network, each route contains several road sections, and J is a set of intersections of multiple routes in the road network;
[0047] The route r refers to a complete path that can be independently named in the road network, and is defined as:
[0048] r = ( rid , len , ( jid j , pos j ) j = 1 m ) ;
[0049] Among them, rid is the route identifier; len represents the route length, len∈[0,1]; Represents the intersection on the ...
Example Embodiment
[0068] Specific implementation manner 2: the following combination Figure 1 to Figure 12 To illustrate this embodiment, this embodiment is a further description of Embodiment 1. The specific implementation process of the KNN query initial set calculation described in step 3 of this embodiment is:
[0069] First, establish a priority queue PQueue to save the neighboring points in the query process. The elements in the priority queue PQueue are sorted according to the distance from the query point from small to large, and the initial value of the priority queue PQueue is set to be empty;
[0070] Establish a queue ResultList to save query results, the length of the queue ResultList is K, the elements in the queue are arranged in ascending order of distance from the query point, and the initial value of the queue ResultList is empty;
[0071] When sending a query request, let q represent the query point, o i Indicates the point of interest to be queried, where i is a positive integer, ...
Example Embodiment
[0078] Specific implementation manner three: the following combination Figure 1 to Figure 12 To explain this embodiment, this embodiment is a further explanation of Embodiment 1. The CKNN query update in step 3 of this embodiment is divided into two situations. When the position of the query point object is unchanged, and the point of interest object moves When using the KNN monitoring area generated by the query process to reduce the query update cost, the implementation process is:
[0079] When the query point object does not move, since the position of the query object remains unchanged, the KNN monitoring area generated by the last query is also unchanged. According to the difference in the number of objects k′ in the KNN monitoring area after the point of interest object is updated, it can be divided Deal with three cases separately:
[0080] 1. When the point of interest object k′=k in the KNN monitoring area, it is only necessary to find all the moving objects on the road...
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