KR20160135907A

KR20160135907A - An extended System and Method for searching nearest spatial entity based on tree index

Info

Publication number: KR20160135907A
Application number: KR1020150069055A
Authority: KR
Inventors: 최형림; 김재중; 이재기; 김채수; 이강배; 박병권; 정준우; 박창현; 최성필; 문영식; 김태훈; 이병하; 조재희; 전미진; 박민선
Original assignee: 동아대학교 산학협력단
Priority date: 2015-05-18
Filing date: 2015-05-18
Publication date: 2016-11-29

Abstract

The present invention relates to an extended system to search the nearest spatial entity based on an R-tree index and a method thereof capable of rapidly searching the nearest spatial entity from the current location of a moving body by extending an R-tree search method. The extended system comprises: a minimum bounding rectangle (MBR) longitude and latitude coordinate management unit to manage an MBR longitude and latitude coordinate surrounding a rectangle that forms a region with respect to all spatial entities expressed in terms of longitude and latitude; an R-tree index construction unit to construct an R-tree index with respect to the MBR managed by the MBR longitude and latitude coordinate management unit; a moving body location tracking unit to track the location of the moving body by receiving a longitude and latitude coordinate of the moving body; an MBR search unit to start searching an MBR including the current location of the moving body from a root node of the R-tree index and search an MBR including the moving body among MBRs located at a node when reaching the final node; and a nearest spatial entity determination unit to calculate the shortest distance from the moving body among the spatial entities searched in the MBR search unit to the nearest MBR, search MBRs again based on the location of the moving body and select the nearest spatial entity to the moving body among all the spatial entities included in the MBR.

Description

[0001] The present invention relates to an apparatus and method for searching for an extended closest spatial entity based on an R-tree index,

More particularly, the present invention relates to an extended R-tree search method for expanding an R-tree search method for searching for a nearest neighbor object closest to a current position of a moving object, And an apparatus and method for searching near-end entities.

In a method using a GPS (Global Positioning System) as a method of providing position information of a moving object such as a vehicle, it may be impossible to measure the position of a moving object by disconnection of a GPS signal. It is greatly affected.

RFID, wireless LAN, UWB (Ultra-Wide Band) technology, etc. are being used for indoor location tracking.

A method of using RFID is to install an RFID reader on a moving path of a moving object and to install an RFID tag on a moving object so that the moving object can know the position of the moving object by exchanging information between the RFID reader and the RFID tag.

However, in the method of using RFID, as the communication radius between the RFID reader and the RFID tag increases, the recognition distance error increases by the communication radius, and if the communication radius is narrow, the RFID tag may not be recognized.

In addition, when the moving object moves at a high speed, even when the RFID reader passes over the RFID tag according to the radius of the communication, the tag response rate may be slow and the tag may not be recognized.

Therefore, the position information of the moving object should be measurable everywhere, the position information of the moving object may not be obtained in a specific area, or the position information may be temporarily stopped due to the change of the moving environment.

That is, when the speed of the moving object is large and the instantaneous traveling route is large, the communication radius of the RF signal is exceeded, and the tracking of the vehicle position is temporarily stopped after entering the room.

Particularly, in the moving object position tracking method of the related art as described above, the current position of the moving object is entered into a square object expressed by a latitude and longitude coordinates on a general map, or by confirming the entry and exit with reference to a virtual boundary indicated by a line, There is a problem in terms of efficiency and accuracy.

In order to determine which spatial entity the moving object will enter and which spatial entity among the numerous spatial entities, it is necessary to first search for the closest spatial entity at the current position of the moving object. To search for a large number of spatial objects stored in the database without performing a full scanning You should build an index.

The R-tree index, which is widely used as spatial index, is a grouping of spatial entities close to each other to reduce the search space.

In the R-tree index search algorithm of the related art, search is performed only within the group including the current coordinates of the moving object. However, there is a problem in that accurate search can not be guaranteed because there is a closest spatial entity in the neighboring group.

That is, in order to avoid scanning a large number of spatial entities, an R-tree index is generated and only entities within a limited range are searched. However, the R-tree search method of the related art has a limitation in finding a nearest object.

Korean Patent Publication No. 10-2014-0060778 Korean Patent Publication No. 10-2014-0122939

The present invention solves the problem of moving object position tracking as described above. When a large number of spatial objects are stored in a database, an R-tree search is performed to quickly and accurately search for a spatial object closest to the current position of the mobile object. And an object of the present invention is to provide an apparatus and method for searching an extended near-end spatial entity based on an index.

The present invention extends to an R-tree search method and an R-tree index-based extended nearest neighbor search apparatus and method for quickly searching for a nearest neighbor object in a current location of a mobile object The purpose is to provide.

The present invention utilizes an MBR (Minimum Bounding Rectangle) that encloses a rectangle forming an area for all spatial entities, expressed by the coordinates of the lower left point and the upper right point, And an object of the present invention is to provide an apparatus and method for searching for an extended closest spatial entity based on an R-tree index so as to greatly improve the accuracy of the nearest neighbor query processing.

The present invention utilizes MBR (Minimum Bounding Rectangle) to enclose a square forming the area for all spatial entities, so that the MBR of all spatial objects (schools, stores, streets, roads, department stores, hospitals, And an R-tree index-based extended closest spatial entity search apparatus and method for constructing an R-tree index.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

According to another aspect of the present invention, there is provided an apparatus for searching for an extended closest spatial entity based on an R-tree index, the apparatus comprising: an MBR latitude coordinate system for managing a MBR latitude and a longitude coordinates An R-tree index construction unit for constructing an R-tree index on the basis of an MBR managed by the MBR longitudinality coordinate management unit, a moving object position tracking unit for tracking the position of the moving object by receiving the longitudinal degree coordinates of the moving object, An MBR searching unit for searching an MBR to which the current location of the moving object belongs and searching for an MBR to which the moving object belongs when the MBR reaches the last node starting from the node; The shortest distance to the MBR is searched, the MBR is searched again about the position of the mobile object, It characterized in that it comprises a; all space recently for selecting a mobile object and the nearest spatial object of the object space, the object contact determiner belonging to the MBR.

Here, the MBR latitude and longitude coordinate management unit manages the MBR so that the MBR can be represented by the coordinates of the lower left point and the upper right point.

In order to select a spatial entity closest to the moving object, the nearest spatial entity determiner obtains the shortest distance d from the MBR search space to the MBR nearest to the moving object, and calculates the shortest distance d A circle having a radius and a circle MBR is detected to search for an MBR intersecting with the original MBR among the neighboring MBRs and a spatial entity closest to the moving object among all the spatial entities belonging to the MBR is selected .

According to another aspect of the present invention, there is provided a method of searching for an extended nearest neighbor object based on an R-tree index, the method comprising: searching for an MBR latitude degree coordinate system that manages a MBR latitude and a longitude coordinates A tree index construction step of constructing an R-tree index based on MBR, a moving object position tracking step of tracking the position of a moving object by receiving the longitudinal degree coordinates of the moving object, starting from the root node of the R-tree index, Searching for MBRs belonging to the moving object and searching for MBRs to which the moving object belongs among the MBRs in the node when reaching the last node; obtaining a shortest distance from the mobile object to the nearest MBR among the searched spatial objects in the MBR searching step; The MBR is searched around the location of the MBR, and all the spatial objects It characterized in that it comprises a; nearest object area determination step of selecting a movable body and the nearest spatial object.

In the nearest spatial entity determination step, the shortest distance d from the moving object to the nearest MBR among the spatial entities searched in the MBR searching step to select a spatial entity closest to the moving object is obtained. Searching for a circle whose radius is the shortest distance d and detecting a circle MBR and searching for an MBR that intersects the circle of the circle among the neighboring MBRs; And a step of selecting the step of selecting the step.

The apparatus and method for searching for the near-end spatial entity based on the R-tree index according to the present invention have the following effects.

First, the accuracy of the nearest neighbor query processing using the R tree index can be greatly improved.

Second, when a large number of spatial objects are stored in the database, the spatial object closest to the current position of the moving object can be retrieved quickly and accurately.

Third, by expanding the R-tree search method, it is possible to quickly search for the nearest neighbor object nearest to the current position of the moving object, thus making it possible to efficiently utilize it.

Fourth, by using the minimum bounding rectangle (MBR), which is expressed by the latitude and longitude coordinates of the lower left point and the upper right point, The accuracy of the nearest neighbor query processing can be improved.

FIG. 1 is a block diagram of an apparatus for searching for an extended closest spatial entity based on an R-tree index according to the present invention
2 is a block diagram showing a MBR representation method of a spatial entity area
3 is a diagram showing an example of R-tree index construction and a current position of a moving object
4 is a diagram showing an example of an R tree index node structure
5 is a block diagram showing an R tree index search
FIG. 6 is a diagram showing a R tree index extended search method
FIG. 7 is a flowchart illustrating a method of searching for an extended nearest neighbor object based on an R tree index according to the present invention.

Hereinafter, a preferred embodiment of an apparatus and method for searching for an extended near-spatial entity based on an R-tree index according to the present invention will be described in detail.

The features and advantages of an apparatus and method for searching for an extended near-spatial entity based on an R-tree index according to the present invention will be apparent from the following detailed description of each embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an apparatus for searching for an extended closest spatial entity based on an R-tree index according to the present invention.

The present invention extends the R-tree search method so that the nearest neighbor object closest to the current position of the moving object can be quickly searched.

To do this, we use an MBR (Minimum Bounding Rectangle), which is expressed by the coordinates of the lower left point and the upper right point, So that the accuracy of the nearest neighbor query processing can be increased.

1, the R-tree index-based extended closest spatial entity search apparatus according to the present invention is represented by a latitude and a longitude coordinates of a lower left point and an upper right point, An MBR latitude and longitude coordinates managing unit 10 for managing the minimum bounding rectangle (MBR) latitude and longitude coordinates which surrounds a rectangle constituting the area, and an MBR (Minimum Bounding Rectangle) managed by the MBR latitude and longitude coordinates managing unit 10, An R-tree index constructing unit 11 for constructing an index, a moving object position tracking unit 12 for receiving the moving object's positional latitude coordinate and tracking the position of the moving object, and a current position of the moving object starting from the root node of the R- An MBR retrieving unit 13 retrieving an MBR to which a moving object belongs among the MBRs in the node when reaching the last node, The shortest distance from the moving object to the closest MBR among the spatial objects is searched to search the MBR around the position of the moving object to determine the closest spatial object to select the closest spatial object among all the spatial objects belonging to the corresponding MBR (14).

The R-tree index-based extended closest spatial entity search apparatus according to the present invention receives and manages the latitude and longitude coordinates of the current location of the moving object, and performs MBR (Minimum Bounding Rectangle).

2 is a block diagram illustrating a method of MBR representation of a spatial entity area.

The R-tree index construction unit 11 constructs an R-tree index by grouping the MBRs of all spatial entities (schools, stores, streets, roads, department stores, hospitals, etc.)

3 is a block diagram showing a construction example of an R-tree index and a current position of a moving object.

FIG. 3 shows an example of construction of an R-tree index for six spatial entities MBR of R1, R2, R3, R4, R5, and R6 and a current moving object position.

The spatial entity closest to the moving object is R2.

Let R7 be the MBR grouping R1, R2, R3 into groups, R8 be the MBR grouping R4, R5, R6, and R9 be the MBR grouping R7, R8 into groups. Respectively.

4 is a configuration diagram showing an example of an R tree index node structure.

Given the current location of the mobile object, the nearest spatial entity can be found through the following Extended Search method using the R tree index.

FIG. 5 is a configuration diagram showing an R tree index search. FIG.

As shown in FIG. 5, starting from the root node of the R-tree index, the MBR to which the current position of the moving object belongs is searched. When reaching the last node, it searches for the MBR to which the mobile belongs among the MBRs at the node.

In Fig. 5, R8 is selected as an example of the search result.

Selects a spatial entity closest to the mobile entity among the spatial entity MBRs belonging to R8.

6 is a configuration diagram illustrating an R-tree index extended search method.

R5 was selected as in Fig.

However, in reality, the spatial object R2 belonging to the neighboring MBR R7 is closer to the mobile object. Therefore, the actual nearest neighbor object is R2, so we need to find it.

For this, the shortest distance d to the closest R5 to the moving object among the spatial entities in R8 is obtained.

Let a circle with radius d around the location of the mobile object and find the MBR of the circle.

And searches for MBRs that intersect with the original MBR among neighboring MBRs in the same node as R8.

In the example of Fig. 6, R7 was searched.

And selects the closest spatial entity among all the spatial entities belonging to R7.

In the example of Fig. 6, R2 was selected.

Among the selected spatial entities (R5 and R2 in the example of FIG. 6), the spatial entity closest to the moving object is determined as the closest spatial entity.

Therefore, the last selected spatial entity in the closest spatial entity determiner 14 is R2.

As described above, according to the present invention, when an R-tree index is constructed with respect to MBRs of a large number of spatial entities and an approximate closest spatial object closest to the current position of the moving object is searched for using the extended search method, .

Specifically, an extended nearest neighbor object search method based on the R-tree index according to the present invention will be described.

FIG. 7 is a flowchart illustrating a method of searching for an extended nearest neighbor object based on an R-tree index according to the present invention.

First, a step of managing the minimum bounding rectangle (MBR) latitude and longitude coordinates which is expressed by the latitude and the longitude coordinates of the lower left point and the upper right point and encloses a rectangle constituting the area with respect to all spatial entities (S701)

Then, an R-tree index is constructed on the basis of the MBR (Minimum Bounding Rectangle) (S702)

In step S703, the mobile node searches for the MBR to which the current position of the moving object belongs, starting from the root node of the R tree index.

When reaching the last node, the MBR to which the mobile belongs is searched among the MBRs at the node (S705)

Then, the moving object and the closest spatial entity are selected from among the spatial entity MBRs in the retrieved MBR (S706)

Then, it is determined whether an extended search is necessary (S707)

If it is determined that the extended search is necessary, the shortest distance d from the searched spatial entities to the MBR closest to the moving object is obtained (S708)

Next, a circle having a radius of the shortest distance d around the position of the moving object is detected, and a circular MBR is detected (S709)

In step S710, MBRs intersecting with the original MBR among neighboring MBRs are searched for, and a spatial entity closest to the moving object among all the spatial entities belonging to the MBR is selected in step S711.

The apparatus and method for searching near-extended spatial entity based on the R-tree index according to the present invention can be applied to all spatial entities (schools, stores, etc.) utilizing an MBR (Minimum Bounding Rectangle) , Distance, road, department store, hospital, etc.), by constructing an R-tree index by grouping them near to each other.

As described above, it will be understood that the present invention is implemented in a modified form without departing from the essential characteristics of the present invention.

It is therefore to be understood that the specified embodiments are to be considered in an illustrative rather than a restrictive sense and that the scope of the invention is indicated by the appended claims rather than by the foregoing description and that all such differences falling within the scope of equivalents thereof are intended to be embraced therein It should be interpreted.

10. MBR latitude and longitude coordinate management unit 11. R tree index construction unit
12. Moving object position tracking unit 13. MBR searching unit
14. The closest spatial object determining unit

Claims

An MBR latitude and longitude coordinate management unit for managing MBR latitude and longitude coordinates which are expressed by latitude and longitude coordinates and enclose a square constituting the area with respect to all spatial entities;
An R-tree index construction unit for constructing an R-tree index based on an MBR managed by the MBR longitude and latitude coordinate management unit;
A moving object position tracking unit for receiving the coordinates of the latitude and longitude of the moving object and tracking the position of the moving object;
An MBR search unit searching an MBR to which a current location of a moving object belongs, starting from a root node of an R-tree index, and retrieving an MBR to which a moving object belongs among MBRs in the node when reaching the last node;
The shortest distance from the MBR searching unit to the nearest MBR to the moving object is obtained and the MBR is searched again based on the position of the moving object to select the moving object and the nearest spatial object among all the spatial objects belonging to the MBR And a nearest neighboring object determining unit for determining a nearest neighboring object based on the R-tree index.

The method according to claim 1, wherein the MBR latitude /
Wherein the MBR is managed so as to be represented by the coordinates of the lower left point and the upper right point.

2. The method according to claim 1,
In order to select a spatial entity closest to the moving object, the shortest distance d from the MBR searching section to the MBR closest to the moving object is obtained,
A circle whose radius is the shortest distance d around the position of the moving object is detected, and a circle MBR is detected to search for an MBR intersecting with the original MBR among neighboring MBRs, and among the all spatial entities belonging to the MBR, Wherein the R-tree index-based extended closest-space object search apparatus selects a near-spatial-object object.

A MBR latitude and longitude coordinates management step of managing MBR longitude and latitude coordinates, which are expressed by latitude and longitude coordinates and enclose a square constituting the area with respect to all spatial entities;
An R-tree index building step of constructing an R-tree index based on the MBR;
A moving object position tracking step of receiving a positional deviation of the moving object and tracking the position of the moving object;
An MBR search step of searching an MBR to which the current position of the moving object belongs, starting from the root node of the R-tree index, and searching for the MBR to which the moving object belongs among the MBRs at the node when reaching the last node;
The shortest distance from the mobile object to the MBR nearest to the mobile object is searched for in the MBR search step and the MBR is searched again based on the mobile object position to select the mobile object and the nearest spatial object among all the space objects belonging to the MBR And determining a nearest neighbor object based on the R-tree index.

5. The method according to claim 4, wherein in the closest spatial entity determination step,
Obtaining a shortest distance d from the mobile object to the nearest MBR among the spatial objects searched in the MBR search step to select a spatial object closest to the mobile object;
Detecting a circle whose radius is a shortest distance d about the position of the moving object and detecting a circle MBR to search for an MBR intersecting with the original one of the neighboring MBRs;
And selecting a spatial entity closest to the moving object among all spatial entities belonging to the corresponding MBR.