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Reverse k nearest neighbor query method based on Voronoi pictures

A query method and nearest neighbor technology, applied in the field of query and spatial data query, can solve problems such as low efficiency and unsupported, and achieve the effect of taking into account the query speed

Inactive Publication Date: 2013-06-19
SHENYANG JIANZHU UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] (2) Does not support dynamically changing k value
Therefore, this technique is not suitable for situations where the value of k is not known in advance or may be changed dynamically
[0010] (3) Inefficient update operation

Method used

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  • Reverse k nearest neighbor query method based on Voronoi pictures
  • Reverse k nearest neighbor query method based on Voronoi pictures
  • Reverse k nearest neighbor query method based on Voronoi pictures

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] A kind of reverse k-nearest neighbor query method based on Voronoi graph, comprises the following steps:

[0037] Step 1: Generate corresponding Voronoi diagrams according to the set of query sites, the method is: the existing Voronoi diagram generation method; because each k-order Voronoi diagram in the present invention can query R(k-1)NN, RkNN and R(k+1 ) NN results, so according to the needs of the query to generate 1, 3, 6, 9... order Voronoi diagram;

[0038] Step 2: Import the query object data set, the method is: read the data file and display the data;

[0039] Step 3: Input the k value and the coordinates of the query point q, call the Voronoi diagram with order m generated in step 1 according to the k value, and get the RkNN query result, where:

[0040] When k=m, all query objects within the polygon containing station q are the results,

[0041] When k

Embodiment 2

[0045] Such as image 3 As shown, a real human landscape landmark data set CD is used to further illustrate the reverse k-nearest neighbor query method based on the Voronoi diagram proposed by the present invention. Include the following steps:

[0046] Step 1: Generate Voronoi graphic data according to the CD human landscape site collection, and save the file.

[0047] The document saved by the generate graphics module is as follows Figure 4 As shown, the data in the figure is the data of the third-order Voronoi diagram. Each row of data may describe a Voronoi polygon. The data in each row is divided into three parts, namely the generator, the vertices of the Voronoi polygon and the minimum bounding rectangle MBR. Each part of data is separated by ":". Let's look at the first row of data, the 6 sets of numbers before the first ":" are the generators of the polygon. Every two sets of numbers represent a pair of coordinates, because it is a polygon of order 3, and 3 pair...

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Abstract

The invention discloses a reverse k nearest neighbor query method based on Voronoi pictures and belongs to the technical field of spatial data query. The method comprises the following steps: step1, corresponding Voronoi pictures are generated according to a query station set; step2, a query object data set is led in; step3, coordinates of a value k and a query point q are input and the Voronoi pictures generated in the step1 is invoked according to the value k so that an reverse k nearest neighbor (RkNN) query result is obtained; and step4, the query is finished. Double color RkNN query under a frequently varied data set is achieved, namely, results of R(k-1)NN, RkNN and R(k+1)NN can be queried in the Voronoi pictures at a certain step k. According to the reverse k nearest neighbor query method based on the Voronoi pictures, pre-calculation amount is reduced; compared with the prior art, query efficiency is improved greatly; the advantages are obvious along with increase of the number of the query object sets; and applicability of the Voronoi pictures is enhanced.

Description

technical field [0001] The invention relates to a query method, in particular to a reverse k-nearest neighbor query method based on a Voronoi diagram, and belongs to the technical field of spatial data query. Background technique [0002] The mobile object query technology in the spatial database can be applied to the network with mobile objects such as urban transportation, aerospace, communication network, etc. It can mine information according to a large amount of spatio-temporal data to provide relevant consultation to customers. Typical spatial queries are nearest neighbors (NN) query and k nearest neighbors (k nearest neighbors, kNN) query. For example: Passengers will ask which hotel is the closest to the station; drivers will inquire where the two nearest gas stations are. Reverse nearest neighbors (reverse nearest neighbors, RNN) query is a variant of NN query, which answers who regards the query object as the nearest neighbor. For example, a series of chain stores...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/30
Inventor 宋晓宇孙焕良许景科王永会赵明
Owner SHENYANG JIANZHU UNIVERSITY