KR101985731B1 - Device and Method thereof for Redundant Data Reduction in Wireless Sensor Networks - Google Patents

Abstract

Disclosed is a device for reducing redundant data in a wireless sensor network and a method thereof. According to the present invention, the device for reducing redundant data comprises: an extraction unit which extracts a difference value in a sensing position and a difference value in a sensing time between a first sensing data and second sensing data from a sensing position data and a sensing time data, respectively included in the first sensing data, which is received from a first lower-ranking sensor node, and the second sensing data, which is received from a second lower-ranking sensor node, from among the data received by a higher-ranking sensor node; and a determination unit which, when the difference value in the sensing position is the same as or lower than a position threshold value () and the difference value in the sensing time is the same as or lower than a time threshold value (), determines that one of the first sensing data and second sensing data is a redundant data. The present invention aims to provide a device for reducing redundant data in the wireless sensor network and a method thereof, which are able to improve an energy efficiency of a mobile IoT smart sensor and a transmission efficiency of the whole sensor network.

Description

TECHNICAL FIELD [0001] The present invention relates to a redundant data reduction apparatus and a method thereof for a wireless sensor network,

The present invention relates to an apparatus and method for reducing redundant data, and more particularly, to an apparatus and method for identifying and reducing redundant data using sensing position and time data of sensing data.

A sensor network is a technology that provides services such as monitoring, tracking, reconnaissance, and automation using a plurality of communication nodes having sensing, processing, and communication capabilities. The sensor network is not a means of communication, but an automated remote data collection. In particular, wirelessly communicating sensor networks include sensor nodes with limited performance. The sensor nodes measure and collect the environmental data in which each sensor node is located. The collected data is transmitted to a server or a user located at a remote place through a broadband network through a wireless interface.

Mobile IoT (Internet of Things) mobile sensors with mobility are sensed in the sensor network and transmit the collected data to the neighboring sensor node and finally transmit to the sink node. Since mobile IoT smart sensors collect data while moving, many sensor nodes may be located at adjacent distances and collect data with no significant difference within meaningless time difference. As a result, mobile IoT smart sensors may be unnecessary There is a problem in that the lifetime of the entire wireless sensor network composed of the sensor nodes using limited energy is shortened as the data is continuously transmitted.

Therefore, when mobile IoT smart sensor nodes transmit the collected data, it is possible to increase the energy efficiency of the sensor node and the transmission efficiency of the entire sensor network by selecting unnecessary data and transmitting only necessary data.

Korea registered patent KR 10-1644750 (registered on July 26, 2016) Korean Patent Publication KR 10-2011-0070049 (published on June 24, 2011)

SUMMARY OF THE INVENTION An object of the present invention is to provide a mobile IoT smart sensor that collects data from a mobile IoT smart sensor in a long data collection cycle or receives data from another mobile IoT smart sensor, And transmits the meaningful data only to other sensors, thereby improving the energy efficiency of the mobile IoT smart sensor and the transmission efficiency of the entire sensor network.

) 이하이고, 상기 센싱 시간 차이값이 시간 임계값(

) 이하이면 상기 제1 센싱 데이터 및 상기 제2 센싱 데이터 중 어느 하나를 중복 데이터로 판별하는 판별부를 포함할 수 있다.The apparatus for reducing redundancy according to an embodiment of the present invention includes a first sensor node and a second sensor node that are included in the first sensor data received from the first lower sensor node and the second sensor data received from the second lower sensor node, An extraction unit for extracting a sensing position difference value and a sensing time difference value between the first sensing data and the second sensing data from the sensing position data and the sensing time data,

) And the sensing time difference value is less than a time threshold value

), It may include a discrimination unit which discriminates any one of the first sensing data and the second sensing data as redundant data.

The apparatus may further include a removal unit for removing the redundant data.

Here, if the upper sensor node receives the first sensing data and the second sensing data, the determination unit may determine whether the data is redundant.

The determining unit may determine whether the data stored in the buffer of the upper sensor node exceeds the buffer threshold value set in the buffer.

) 및 상기 시간 임계값(

)은 상기 제1 센싱 데이터 및 상기 제2 센싱 데이터의 통계적 유의성이 높을수록 작은 값을 가질 수 있다.Here, the position threshold value (

) And the time threshold value (

May have a smaller value as the statistical significance of the first sensing data and the second sensing data is higher.

If the first sensing data and the second sensing data are determined to be duplicated data, the removal unit may further delete the first sensor data and the second sensing data from the upper one of the first lower sensor node and the second lower sensor node, It is possible to preferentially remove the sensing data collected from the lower sensor node located at a remote location.

Here, the buffer threshold may be set to be relatively higher than a sensor node located further from the sink node as the sensor node adjacent to the sink node.

)이하이고, 상기 센싱 시간 차이값이 시간 임계값(

) 이하이면 상기 제1 센싱 데이터 및 상기 제2 센싱 데이터 중 어느 하나를 중복 데이터로 판별하는 단계, 및 (c) 상기 중복 데이터를 제거하는 단계를 포함할 수 있다.The redundant data reduction method according to an embodiment of the present invention includes the steps of (a) receiving first sensing data from a first lower sensor node and second sensing data received from a second lower sensor node among data received by an upper sensor node, Extracting a sensing position difference value and a sensing time difference value between the first sensing data and the second sensing data from the sensing position data and the sensing time data respectively included in the first sensing data and the second sensing data,

) And the sensing time difference value is less than a time threshold value

), Determining either one of the first sensing data and the second sensing data as redundant data, and (c) removing the redundant data.

In the step (b), when the upper sensor node receives the first sensing data and the second sensing data, it may determine whether the data is redundant.

The step (b) may determine whether the data stored in the buffer of the upper sensor node exceeds the buffer threshold value set in the buffer.

) 및 상기 시간 임계값(

)은 상기 제1 센싱 데이터 및 상기 제2 센싱 데이터의 통계적 유의성이 높을수록 작은 값을 가질 수 있다.Here, the position threshold value (

) And the time threshold value (

May have a smaller value as the statistical significance of the first sensing data and the second sensing data is higher.

The upper sensor node may transmit data stored in the buffer to the neighboring sensor node of the upper sensor node when the data stored in the buffer of the upper sensor node from which the redundant data is removed exceeds the buffer threshold value have.

According to an exemplary embodiment of the present invention, it is possible to identify duplicate data, which is data having no significant difference among the sensing data received by the sensor node.

In addition, by transmitting only the remaining data to the other sensor, the energy efficiency of the sensor node and the transmission efficiency of the entire sensor network can be improved and the service life can be extended.

1 is an exemplary block diagram of a sensor node including a redundant data reduction device according to an embodiment of the present invention.
2 is an exemplary block diagram of a redundant data reduction device in accordance with an embodiment of the present invention.
3A shows that data is transferred from a lower sensor node to an upper sensor node in a grouped wireless sensor network.
FIG. 3B illustrates the identification and removal of redundant data in the grouped wireless sensor network shown in FIG. 3A.
FIG. 4 is a flowchart illustrating a redundant data reduction method using a redundant data reduction apparatus according to an embodiment of the present invention shown in FIG. 1 and FIG. 2. Referring to FIG.

It is to be understood that the specific structural or functional descriptions of embodiments of the present invention disclosed herein are presented for the purpose of describing embodiments only in accordance with the concepts of the present invention, May be embodied in various forms and are not limited to the embodiments described herein.

Embodiments in accordance with the concepts of the present invention are capable of various modifications and may take various forms, so that the embodiments are illustrated in the drawings and described in detail herein. It should be understood, however, that there is no intention to limit the embodiments according to the concepts of the present invention to the particular forms disclosed, but includes modifications, equivalents, or alternatives falling within the spirit and scope of the present invention.

The terms first, second, or the like may be used to describe various elements, but the elements should not be limited by the terms. The terms may be named for the purpose of distinguishing one element from another, for example without departing from the scope of the right according to the concept of the present invention, the first element being referred to as the second element, Similarly, the second component may also be referred to as the first component.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between. Expressions that describe the relationship between components, for example, "between" and "immediately" or "directly adjacent to" should be interpreted as well.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms " comprises ", or " having ", and the like, are used to specify one or more of the features, numbers, steps, operations, elements, But do not preclude the presence or addition of steps, operations, elements, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning of the context in the relevant art and, unless explicitly defined herein, are to be interpreted as ideal or overly formal Do not. Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.

1 is an exemplary block diagram of a sensor node including a redundant data reduction device according to an embodiment of the present invention.

Referring to FIG. 1, a sensor node 10 including a redundant data reduction device may include a sensing unit 100, a redundant data reduction device 200, a buffer 300, and a communication unit 400.

The sensing unit 100 senses specific parameters of an object to be sensed according to predetermined conditions, and generates sensing data and stores the sensed data in the buffer 300. For example, the sensing unit 100 may sense various parameters such as temperature, humidity, and illumination of an object to be sensed.

The redundant data reduction device 200 discriminates and removes redundant data from sensing data received from another sensor node. The specific operation of the redundant data reduction apparatus 200 will be described later with reference to FIG. 2 to FIG.

The buffer 300 stores data sensed by the sensor node and sensing data received from another sensor node. Meanwhile, a buffer threshold value may be set for each sensor node, and the buffer threshold value may be set to be relatively higher than a sensor node located farther from the sink node as the sensor node adjacent to the sink node increases the energy consumption of the sensor node. It can be optimized.

The communication unit 400 transmits the sensing data generated by the sensing unit 100 to the upper sensor node, receives data sensed by the lower sensor node from the lower sensor node, and transmits data exceeding the buffer threshold value set in the sensor node It is possible to transmit data to another sensor node only when it is stored in the buffer 300. [ Here, the lower sensor node means a sensor node that transmits sensed data to an upper sensor node, and the upper sensor node receives sensing data from a lower sensor node to discriminate and remove the redundant data, Means a sensor node transmitting to another upper sensor node. The communication unit 400 may be configured in various forms according to the transmission / reception mode, frequency, and function.

2 is an exemplary block diagram of a redundant data reduction device 200 according to an embodiment of the present invention.

Referring to FIG. 2, the redundant data reduction apparatus 200 may include an extraction unit 210, a determination unit 230, and a removal unit 250.

The extracting unit 210 extracts data for discriminating whether the first sensing data and the second sensing data received from the first lower sensor node and the second lower sensor node are duplicated data. Here, the first lower sensor node and the second lower sensor node are the sensor nodes that have transmitted the sensing data to the upper sensor node among the lower sensor nodes, and the first sensing data and the second sensing data correspond to the first lower sensor node and the second lower sensor node, It is the data that each sensor node senses.

The sensing data transmitted by the lower sensor node to the upper sensor node includes position data and time data sensing the sensed data. The extracting unit 210 extracts the received first sensing data A sensing position difference value and a sensing time difference value are extracted between the sensing data and the second sensing data.

) 및 시간 임계값(

)과 비교한다. 이때, 위치 임계값은 수신한 센싱 데이터 간에 센싱된 위치의 인접성을 나타내는 척도이며, 시간 임계값은 수신한 센싱 데이터 간에 센싱된 시간의 인접성을 나타내는 척도이다.When the upper sensor node receives the sensing data from the lower sensor node, the determination unit 230 determines whether the received first sensing data and the second sensing data are redundant data. More specifically, when the sensing unit 230 receives the sensing data from the lower sensor node, the sensing unit 230 extracts the sensed position difference value and the sensed time difference value from the position threshold value (

) And time threshold (

). At this time, the position threshold value is a measure indicating the proximity of the position sensed between the received sensing data, and the time threshold value is a measure indicating the proximity of the sensed time between the received sensing data.

Therefore, if the sensing position difference value is equal to or less than the predetermined position threshold value and the sensing time difference value is less than the predetermined time threshold value, the first sensing data and the second sensing data, which are the comparison target sensing data, Since the data is collected at the adjacent time, it can be discriminated as duplicate data.

Since the determination unit 230 uses only the sensing position difference value and the sensing time difference value extracted by the extraction unit 210 instead of checking or comparing the actual data value to determine whether the sensing data is redundant data, . On the other hand, the position threshold value and the time threshold value may have a smaller value as the statistical significance of the sensing data is higher, so that the discrimination condition of the redundant data may be strict.

The determination unit 230 according to another embodiment of the present invention does not determine whether duplicate data is received after the sensor node receives the data but the data stored in the buffer 300 of the upper sensor node is stored in the buffer 300 Only when the threshold value is exceeded, it is possible to judge whether or not the data is redundant. This is because even if the buffer threshold value is not exceeded according to the wireless sensor network, if the redundant data is discriminated, the transmission efficiency of the entire sensor network may be deteriorated.

The removal unit 250 removes the duplicated data determined by the determination unit 230. More specifically, if the received first sensing data and second sensing data are discriminated as duplicate data, either the first sensing data or the second sensing data is removed. At this time, in the case of the sensing data received from the lower sensor node located farther away, the signal intensity may be weakened or distorted. Therefore, the removal unit 250 may relatively remove the sensor data from the upper sensor node among the first lower sensor node and the second lower sensor node. The sensing data collected from the lower sensor nodes located farther away may be preferentially removed, but the present invention is not limited thereto.

Meanwhile, the redundant data reduction apparatus 200 and method according to an embodiment of the present invention can be applied to a grouped wireless sensor network. The grouping of wireless sensor nodes groups the sensor nodes in the wireless sensor network so that the sensor nodes of the assigned group transmit data to the sensor nodes of the next higher group, thereby reducing the overhead of the sensor nodes and efficiently consuming the limited energy The distance between the sink node and the sensor node, the placement information of the sensor node, and the like. In the grouped sensor network, the buffer threshold value is set differently for each group, so frequent data transmission can be reduced and the energy efficiency of the sensor node can be increased.

3A shows a process of transmitting data from a lower sensor node to an upper sensor node in a grouped wireless sensor network.

3A, the B sensor node and the C sensor node are the lower sensor nodes, the A sensor node is the upper sensor node, the B sensor node and the C sensor node belonging to the group N + 1 are data 1 sensing data and the second sensing data to the node A belonging to the next higher level group N. Each of the first sensing data and the second sensing data includes sensing position data (p) and sensing time data (t). The A sensor node stores the first sensing data and the second sensing data received from the B sensor node and the C sensor node, the data stored in the buffer 300, And determines whether the first sensing data and the second sensing data are redundant data.

FIG. 3B illustrates the identification and removal of redundant data in the grouped wireless sensor network shown in FIG. 3A.

The A sensor node deletes either the first sensing data or the second sensing data when the first sensing data and the second sensing data are discriminated as redundant data through the redundant data reduction apparatus 200. [ Referring to FIG. 3B, the sensing position data p and the sensing time data t of the first sensing data and the second sensing data are compared with each other, and one of the data determined as the redundant data in the sensing data is deleted.

Accordingly, the first sensing data and the second sensing data except the data sensed by the A sensor node and the redundant data are stored in the buffer 300 of the A sensor node. Thereafter, when the data value stored in the buffer 300 of the A sensor node exceeds the buffer threshold value, the data stored in the buffer 300 is transmitted to the sink node belonging to the group N-1.

FIG. 4 is a flowchart illustrating a redundant data reduction method using the redundant data reduction apparatus 200 according to an embodiment of the present invention shown in FIG. 1 and FIG. Hereinafter, a description overlapping with the above-described portions will be omitted.

In step S210 performed by the extracting unit 210, when the upper sensor node receives data from the lower sensor node, the first sensor data received from the first lower sensor node and the second sensor node received from the second lower sensor node And extracts a sensing position difference value and a sensing time difference value between the first sensing data and the second sensing data from the second sensing data.

)이하이고, 센싱 시간 차이값이 시간 임계값(

) 이하이면 상기 1 센싱 데이터 및 상기 제2 센싱 데이터 중 어느 하나를 중복 데이터로 판별한다.Next, in step S230 performed by the determination unit 230, the sensing position difference value extracted in step S210 is compared with a position threshold value

) And the sensing time difference value is less than the time threshold value

), One of the first sensing data and the second sensing data is discriminated as redundant data.

Finally, in operation S250 performed by the removal unit 250, the duplicated data determined in operation S230 is removed. The data to be removed may be either the first sensing data or the second sensing data determined as the redundant data.

When the data stored in the buffer 300 of the upper sensor node whose redundant data is removed through the redundant data reduction method exceeds the buffer threshold value set to the upper sensor node, the upper sensor node transmits the data stored in the buffer 300 to the upper sensor To the neighboring sensor node of the node. Accordingly, it is possible to reduce the size of data to be transmitted, thereby reducing energy consumed in transmission and reception, and improving transmission efficiency of the entire network.

The apparatus described above may be implemented as a hardware component, a software component, and / or a combination of hardware components and software components. For example, the apparatus and components described in the embodiments may be implemented within a computer system, such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable array (FPA) A programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to execution of the software. For ease of understanding, the processing apparatus may be described as being used singly, but those skilled in the art will recognize that the processing apparatus may have a plurality of processing elements and / As shown in FIG. For example, the processing unit may comprise a plurality of processors or one processor and one controller. Other processing configurations are also possible, such as a parallel processor.

The software may include a computer program, code, instructions, or a combination of one or more of the foregoing, and may be configured to configure the processing device to operate as desired or to process it collectively or collectively Device can be commanded. The software and / or data may be in the form of any type of machine, component, physical device, virtual equipment, computer storage media, or device , Or may be permanently or temporarily embodied in a transmitted signal wave. The software may be distributed over a networked computer system and stored or executed in a distributed manner. The software and data may be stored on one or more computer readable recording media.

The method according to an embodiment may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions to be recorded on the medium may be those specially designed and configured for the embodiments or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI > or equivalents, even if it is replaced or replaced.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (13)

From the sensing position data and the sensing time data respectively included in the first sensing data received from the first lower sensor node and the second sensing data received from the second lower sensor node among the data received by the upper sensor node, And an extracting unit for extracting a sensing position difference value and a sensing time difference value between the second sensing data; And
If the sensed position difference value is a position threshold value

) And the sensing time difference value is less than a time threshold value

), The first sensing data and the second sensing data are discriminated as duplicate data.
The method according to claim 1,
And a removal unit for removing the redundant data.
The method according to claim 1,
Wherein the determination unit determines whether the upper sensor node receives the first sensing data and the second sensing data to determine whether the data is redundant data.
The method according to claim 1,
Wherein the determination unit determines whether the data stored in the buffer of the upper sensor node exceeds the buffer threshold value set in the buffer.
The method according to claim 1,
The position threshold value (

) And the time threshold value (

) Has a smaller value as the statistical significance of the first sensing data and the second sensing data is higher.
3. The method of claim 2,
Wherein when the first sensing data and the second sensing data are determined to be redundant data, the removal unit is located at a position relatively far from the upper sensor node among the first lower sensor node and the second lower sensor node A redundant data reduction device for preferentially removing sensing data collected from a lower sensor node.
5. The method of claim 4,
Wherein the buffer threshold value is set to be relatively higher than a sensor node located farther from the sink node as the sensor node adjacent to the sink node.
12. A redundant data reduction method implemented by the redundant data reduction apparatus of claim 1,
(a) from the sensing position data and the sensing time data included in the first sensing data received from the first lower sensor node and the second sensing data received from the second lower sensor node among the data received by the upper sensor node, Extracting a sensing position difference value and a sensing time difference value between the first sensing data and the second sensing data;
(b) if the sensed position difference value is a position threshold value

) And the sensing time difference value is less than a time threshold value

), Determining whether any one of the first sensing data and the second sensing data is redundant data; And
(c) removing the redundant data.
9. The method of claim 8,
Wherein the step (b) comprises determining whether the upper sensor node receives the first sensing data and the second sensing data to determine whether the data is redundant data.
9. The method of claim 8,
Wherein the step (b) discriminates whether the data stored in the buffer of the upper sensor node exceeds the buffer threshold value set in the buffer.
9. The method of claim 8,
The position threshold value (

) And the time threshold value (

) Has a smaller value as the statistical significance of the first sensing data and the second sensing data is higher.
11. The method of claim 10,
Wherein the upper sensor node transmits the data stored in the buffer to the peripheral sensor node of the upper sensor node when the data stored in the buffer of the upper sensor node from which the redundant data is removed exceeds the buffer threshold value .
A computer-readable recording medium storing a program for executing the method according to any one of claims 8 to 12.

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