CN103412955B

CN103412955B - A RFID Data Compression Method

Info

Publication number: CN103412955B
Application number: CN201310388214.6A
Authority: CN
Inventors: 不公告发明人
Original assignee: Hunan University of Humanities Science and Technology
Current assignee: Hunan University of Humanities Science and Technology
Priority date: 2013-09-01
Filing date: 2013-09-01
Publication date: 2021-08-17
Anticipated expiration: 2033-09-01
Also published as: CN103412955A

Abstract

The invention discloses a RFID data compression method. An extensible data model is used to store the moving path sequence of RFID objects, the residence time interval corresponding to the sequence, and the path diagram respectively, and a path coding mode that can compress RFID reading data is established. Multiple aggregation levels such as stop position, stop start time, and stop end time are used to compress reading data; and according to user needs of RFID applications, different data granularity can be compressed for stop position, stop start time, and stop end time. It can adapt to large-scale RFID object group movement and independent RFID object movement, can express RFID object movement of long path and cyclic path, and support RFID applications such as path-oriented query.

Description

RFID data compression method

Technical Field

The invention relates to the field of data processing of the Internet of things, in particular to a RFID data compression method.

Background

RFID (Radio Frequency Identification) is a non-contact automatic Identification technology, and automatically identifies an electronic product tag having a unique identifier attached to a target object by using a Radio Frequency signal, and acquires attribute and position data of the RFID object. The technology is widely applied to commercial activities as a key technology of the internet of things, and the RFID application can track the historical track of an object according to the position information (data lineage) of the object in different periods.

The reading data is generated in a general form of (EPC, position, tin, tout), and may represent a historical path of the RFID object EPC from tin to tout at the position. Because the RFID objects are often moved simultaneously in large batches and have the same time stamp and dwell position, a large amount of redundant data exists, and the data compression of the RFID objects moved in large batches can obviously improve the execution efficiency of the path-oriented query.

The existing method carries out path compression on a grouping object, uniformly stores the path information of the grouping, can remarkably reduce the connection load of path inquiry, but easily causes the overflow of prime numbers under the condition that an RFID object has a long path, and cannot express the long path. And because the objects may have the same location, i.e., a circular path, at different time intervals, existing methods also fail to address the problem of RFID objects appearing at the same location at different times.

Disclosure of Invention

In order to solve the problems in the prior art, the invention aims to effectively compress RFID data and provide efficient data for RFID applications such as path-oriented query.

To achieve the above object, the present invention provides a method for compressing RFID data, which comprises the following steps.

Step 1): and designing an RFID compressed data storage model.

Step 2): a user specifies a time interval and a location granularity; performing specified time interval granularity grouping on the read data of the timestamp in a time interval specified by a user, and performing previous-stage time interval granularity grouping on the read data of the timestamp not in the time interval specified by the user; the grouping result is put into a stay record table.

Step 3): and performing position granularity grouping on the reading data with the position within the position granularity specified by the user, performing upper-level position granularity grouping on the reading data with the position not within the position granularity specified by the user, and putting the grouping result into a stop record table.

Step 4): and grouping the moving paths of the RFID objects according to the time interval and the position granularity specified by the user, and putting the grouping result into a path sequence list.

Step 5): taking a node without a precursor position as a root node, taking a precursor position node as a father node and taking a successor position node as a child node; and constructing a path diagram for the moving paths of all the RFID objects, and putting the path diagram into the path diagram.

The invention has the beneficial effects that: different from the prior art, the invention can effectively express the time sequence characteristic and the position correlation of the RFID application by effectively compressing and storing the data, can solve the expression problem of the long path and the circular path of the RFID object, and provides high-efficiency data for the RFID application such as path-oriented query and the like.

Drawings

Fig. 1 is a schematic flow chart of an RFID data compression method according to the present invention.

Fig. 2 is a schematic diagram of an RFID data aggregation method according to the present invention.

Fig. 3 is a path diagram of an RFID mobile object according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to specific embodiments and the accompanying drawings.

Fig. 1 is a schematic flow chart of an RFID data compression method according to the present invention. Firstly, designing an RFID compressed data storage model; then, the user designates time intervals and position granularity, the read data is grouped according to the time intervals and the position granularity, and the grouping result is put into a stop record table; grouping the moving paths of the RFID objects according to the time interval and the position granularity specified by the user, and putting the grouping result into a path sequence list; and constructing a path diagram for the moving paths of all the RFID objects and putting the path diagram into the path diagram.

In the RFID compressed data storage model, a path sequence table comprises a path sequence number, a position number, stopping starting time and stopping ending time; the stay record table comprises RFID object numbers and path sequences; the path graph includes a path ID and a parent path.

The time interval grouping of the reading data is realized by performing specified time interval granularity grouping on the reading data of the time stamp in a time interval specified by a user and performing previous-stage time interval granularity grouping on the reading data of the time stamp not in the time interval specified by the user; the grouping result is put into a stay record table.

The position granularity grouping of the reading data is to perform position granularity grouping on the reading data positioned in the position granularity specified by the user, perform upper-level position granularity grouping on the reading data positioned in the position granularity not specified by the user, and place the grouping result in a stop record table.

The method comprises the following steps that a path graph is constructed for moving paths of all RFID objects, nodes without predecessor positions are used as root nodes, nodes with predecessor positions are used as father nodes, and nodes with successor positions are used as child nodes; and constructing a path diagram for the moving paths of all the RFID objects, and putting the path diagram into the path diagram.

Fig. 2 is a schematic diagram of an RFID data aggregation method according to the present invention. The RFID object data is compressed by aggregating the time interval, location and path sequence, compressing the RFID object path into a path sequence table, represented as a path sequence, a path and its dwell time. In the stay record table, the (RFID object number, path number) is used instead of the (RFID object number, position number, stay start time, stay end time).

Wherein the time interval aggregation indicates that the RFID object a is from t1 'to t 2', and the time interval may be expanded from t1 'to t 3'. Thus, although object a is read at timestamp t1 and object b is read at timestamp t2, their dwell times may have the same time interval [ t1 ', t 2' ]. The user may further extend the time interval [ t1 ', t 2' ] to [ t1 ', t 3' ]. Although the object a is read at the time stamps t1 and t3 and the object b is read at the time stamps t2 and t4, their stay times may have the same time interval [ t1 ', t 3' ].

The position aggregation indicates that the information of the object at a plurality of different positions can be aggregated into the information of a single parent class position. Object a is read at position p1 and object b is read at position p2, then their positions may be expanded to position w 1. The objects a are read at positions w1 and w2, respectively, their positions may be expanded to position d 1.

Wherein the path sequence aggregation indicates that the packet objects having the same path can further compress the path through the same sub-path sequence. From the path sequence sq1 to sq3, the path sequence of the object b can be represented as (b, sq13) by aggregating sq1 and sq3, and then from sq1 to sq3 by adopting the path sequence sq 13.

Fig. 3 is a path diagram of an RFID mobile object according to the present invention. The mobile location MP in an RFID application can be represented as a directed graph < V, E >, where V represents a node of MP and E represents object movement between a pair of nodes < Vi, Vj >. In particular, the root node is the location of the RFID object without predecessor nodes, each node being a child of its predecessor node and a parent of its successor node.

The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and those skilled in the art can make variations or modifications within the technical scope of the present invention disclosed in the above description. And are neither required nor exhaustive of all embodiments. And such obvious changes and modifications which fall within the spirit of the invention are deemed to be covered by the present invention.

Claims

1. An RFID data compression method is characterized in that the method is realized by the following steps:

step 1): designing an RFID compressed data storage model;

step 2): a user specifies a time interval and a location granularity; performing specified time interval granularity grouping on the read data of the timestamp in a time interval specified by a user, and performing previous-stage time interval granularity grouping on the read data of the timestamp not in the time interval specified by the user; putting the grouping result into a stay record table;

step 3): performing position granularity grouping on the reading data with the position within the position granularity specified by the user, performing upper-level position granularity grouping on the reading data with the position not within the position granularity specified by the user, and putting the grouping result into a stop record table;

step 4): grouping the moving paths of the RFID objects according to the time interval and the position granularity specified by the user, and putting the grouping result into a path sequence list;

step 5): taking a node without a precursor position as a root node, taking a precursor position node as a father node and taking a successor position node as a child node; constructing a path diagram for the moving paths of all the RFID objects, and putting the path diagram into the path diagram;

wherein, the data dictionary of the RFID compressed data storage model in the step 1) is as follows:

1) a path sequence table: the method comprises the steps of path sequence numbering, position numbering, stay starting time and stay ending time;

2) stay record table: including RFID object numbers and path sequences;

3) path chart: including a path ID and a parent path;

as described in step 4), specifically, the RFID object data is compressed by aggregating the time intervals, positions and path sequences, and the RFID object path is compressed into a path sequence table, which is represented as a path sequence, a path and its dwell time; replacing (RFID object number, position number, stay start time and stay end time) with (RFID object number and path number) in the stay record table;

the time interval aggregation indicates that the RFID object a is from t1 'to t 2', and the expanded time interval is from t1 'to t 3'; thus, although object a is read at timestamp t1 and object b is read at timestamp t2, their dwell times are at the same time interval [ t1 ', t 2' ]; the user further extends the time interval [ t1 ', t 2' ] to [ t1 ', t 3' ]; although the object a is read at the time stamps t1 and t3 and the object b is read at the time stamps t2 and t4, their stay times have the same time interval [ t1 ', t 3' ];

the position aggregation represents that the information of the object at a plurality of different positions is aggregated into the information of a single parent class position; object a is read at position p1 and object b is read at position p2, then their positions are expanded to position w 1; object a is read at positions w1 and w2, respectively, then their positions are expanded to position d 1;

the path sequence aggregation indicates that the grouping objects with the same path further compress the path through the same sub-path sequence; from the path sequence sq1 to sq3, the path sequence of the object b is represented by the path sequence sq13 from sq1 to sq3, and represented by the aggregation sq1 and sq3 as (b, sq 13).