KR102197190B1 - Attendance Management System and Its Operation Method Using Visible Light Communication - Google Patents

Abstract

Disclosed are an attendance management system using visible light communications (VLC) to minimize interference with other communication frequencies and an operation method thereof. According to the present invention, the operation method of the attendance management system using VLC comprises the following processes of: allowing an Internet of things (IoT) server (IS) to transmit an activation message to a VLC transmitter (VT) in accordance with an attendance scheduled table; allowing the VLC transmitter to convert the activation message into an activation frame and using VLC to transmit the activation frame to a VLC receiver (VR); allowing the VLC receiver to transmit an attendance confirmation request message including identification information thereof to the IoT server; allowing the IoT server to store a state of VLC receiver as an attendance state in an attendance book when the attendance confirmation request message is received within an attendance approval period and transmit a result message to the VLC transmitter; and allowing the VLC transmitter to convert the result message info a result frame and transmitting the result frame to the VLC receiver.

Description

Attendance Management System and Its Operation Method Using Visible Light Communication

Embodiments of the present invention relate to an attendance management system and an operation method thereof using visible light communication, and in particular, to an attendance management system and an operation method thereof that perform a verification process to prevent illegal attendance.

The content described in this section merely provides background information on the present invention and does not constitute prior art.

In general, attendance management of a university or company consists of two main things.

Management of the number of attendees at the university is divided into a method by calling a general list and entering a code using a web service. The class list calling method is a method in which the lecturer uses voice to check the attendance of the class. The code input method is a method in which a lecturer generates a random code and posts it on the screen of the lecture room, and the lecturer in the lecture room enters the code on the website for authentication.

However, the roster calling method has a problem that it is insufficient in attendance management due to proxy attendance. The code input method has a problem in that it is difficult to accurately check attendance because people who attend the lecture room leak the code to the outside, so that even people who are not in the lecture room can attend. In addition, since it is difficult to check the number of attendees on behalf of the attendee, it is necessary to identify the number of attendees again, so it takes a long time to manage the number of attendees.

In addition to this, an electronic attendance management system using various electronic devices is being developed to replace the existing call-in method attendance method. The electronic attendance management system is required to quickly and accurately transmit and process student attendance information. To this end, many communication technologies based on electromagnetic waves such as radio frequency identification (RFID), near field communication (NFC), and Bluetooth are used.

The RFID and NFC-based attendance management system uses a tag recognition method that attaches an identification tag to the desk and student ID in each classroom and authenticates with a reader. However, this method requires a lot of installation cost, has inconvenient that the user has to move to the reader to request attendance, and is also vulnerable in terms of verifying illegal attendance. The Bluetooth-based attendance management system manages attendance by identifying whether the user is accurately located near the beacon through the strength of the signal and the unique identifier (UID) of the beacon. However, since the Bluetooth-based attendance management system needs to perform additional work to determine the location and depends on the strength of the signal, it may be affected by interference in an environment where multiple users communicate simultaneously. In addition, Bluetooth uses a frequency band such as Wi-Fi, and there is a problem that signal interference frequently occurs as the spread of Wi-Fi is activated.

In other words, the existing attendance management system is expensive to install, lacks convenience, it is difficult to verify irregular attendance, is affected by interference with other communication frequencies, and uses a frequency band that is restricted in use in hospitals, etc. . As a way to overcome these problems, a study on an attendance management system using visible light communication (VLC) is required.

Embodiments of the present invention reduce the burden of installation cost of the attendance management system by using LED lighting that does not require separate installation, eliminate the inconvenience that the attendance check requester has to move directly to the reader to receive attendance, and the like. The main object of the present invention is to provide an attendance management system and an operation method thereof using visible light communication, which can reduce the influence of the regulation of the frequency band of the network and minimize interference with other communication frequencies.

Another embodiment of the present invention is to provide an attendance management system and an operation method thereof that perform a verification process between a server and a client using an arbitrary random number to verify illegal attendance.

According to an aspect of the present invention, in a method of operating an attendance management system using visible light communication (VLC), an IoT server (IS) is a visible light transmission device (VLC transmitter, VT) according to the attendance schedule. Sending an activation message to ); Converting the activation message into an activation frame by the visible light transmitting device and transmitting the ATCTIVE frame to a visible light receiving terminal (VLC receiver, VR) using visible light communication; The process of transmitting, by the visible light receiving terminal, an attendance confirmation request message including its identification information to the IoT server; When the IoT server receives the attendance confirmation request message within an attendance recognition period, the visible light receiving terminal of the attendance unit Storing the status of the attendance status and transmitting a result message to the visible light transmission device; And converting the result message into a RESULT frame by the visible light transmission device and transmitting the result frame to a visible light receiving terminal.

According to another aspect of the present embodiment, there is provided an attendance management system using visible light communication, comprising: an IoT server that generates an activation message according to an attendance schedule and generates a result message when an attendance confirmation request message is received within an attendance recognition period; A visible light transmitting device that converts the activation message and the result message generated by the IoT server into an activation frame and a result frame, respectively, and transmits it using visible light communication; And a visible light receiving terminal for transmitting an attendance confirmation request message including its own identification information to the IoT server upon receiving the activation frame.

Embodiments of the method of operating the system may further include one or more of the following features.

Transmitting a verification request message including a random number randomly generated by the IoT server receiving the attendance verification request message to the visible light transmitting device; Converting, by the visible light transmission device, the verification request message into a verification request frame (VERIFY frame) and transmitting it to a visible light receiving terminal using visible light; Transmitting, by the visible light receiving terminal, a verification request message including the random number and its own identification information to the IoT server; And verifying, by the IoT server, a random number included in the verification request message and identification information of the visible light receiving terminal.

As described above, according to an embodiment of the present invention, since the existing installed LED lighting infrastructure is used as it is, the installation cost is low, and because the attendance management service is received by transmitting and receiving visible light from a fixed location LED lighting, additional work is required. There is no convenience, and since a frequency band different from other electromagnetic waves is used, the influence of interference of other electromagnetic waves can be reduced. In addition, since the visible light communication can be checked with the naked eye, it is easy to grasp the service provision status.

According to another embodiment of the present invention, since visible light cannot penetrate the wall, the attendance confirmation requester can only be recognized for attendance at the corresponding place, thereby preventing irregular attendance, and performing the verification process of the server and the client. Therefore, it is possible to prevent irregular attendance.

1 is a diagram illustrating a configuration diagram of an attendance management system according to an embodiment of the present invention.
2 is a diagram for explaining a frame structure used for visible light communication according to an embodiment of the present invention.
3 is a diagram exemplified to explain the server and the client side of the attendance management system according to an embodiment of the present invention.
4 is a diagram illustrating a protocol stack structure used in an attendance management system according to an embodiment of the present invention.
5 is a diagram illustrating an initial operation of the attendance management system according to an embodiment of the present invention.
6 is a diagram illustrating an operation process of the attendance management system according to an embodiment of the present invention.
7 is a view for explaining a periodic status check of a visible light transmission device in the attendance management system according to an embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to elements of each drawing, it should be noted that the same elements are assigned the same numerals as possible even if they are indicated on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the subject matter of the present invention, a detailed description thereof will be omitted.

In addition, in describing the constituent elements of the present invention, terms such as first, second, A, B, (a), (b) may be used. These terms are only used to distinguish the component from other components, and the nature, order, or order of the component is not limited by the term. Throughout the specification, when a part'includes' or'includes' a certain element, it means that other elements may be further included rather than excluding other elements unless otherwise stated. . In addition, terms such as'~ unit' and'module' described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software.

Visible light communication, which will be described below, is a technology that communicates using light, and refers to communication in which data is transmitted by repeatedly turning off and on light 200 times per second or more. Visible light communication refers to a technology capable of simultaneously realizing the function of lighting and wireless communication by using a frequency higher than the on-off frequency that can be recognized by humans.

1 is a diagram illustrating a configuration diagram of an attendance management system according to an embodiment of the present invention.

Referring to FIG. 1, the attendance management system using visible light communication includes an Internet of Things server (IoT Server, IS, 100), a visible light communication agent (VLC Agent, VA, 110), and visible light transmission devices (VLC Transmitter, VT, 120, 122, 124) and visible light receiving terminals (VLC Receiver, 130, 132, 134, 136).

Hereinafter, the visible light communication agent 110 is described as being a separate entity from the IoT server 100, but may be implemented as a single entity with the IoT server 100. That is, the IoT server 100 may function as the visible light communication agent 110.

Meanwhile, the attendance management system can be divided into a server and a client. The server includes an IoT server 100, a visible light communication agent 110, and visible light transmission devices 120, 122, and 124, and the client includes visible light receiving terminals 130, 132, 134, and 136.

Hereinafter, the operation process of the attendance management system will be described based on one visible light transmission device 120 and one visible light reception terminal 130, but this is only one embodiment, and other visible light transmission devices 122, 124 ) And other visible light receiving terminals 132, 134, and 136.

The IoT server 100 is a server that provides a visible light communication-based attendance management service to the visible light receiving terminal 130, and generates an activation message according to the attendance schedule, and generates a verification request message and a result message later. It is a component that directly transmits a message to the visible light transmission device 120 or through the visible light communication agent 110, and performs a verification process on the visible light receiving terminal 130. The IoT server 100 may have an attendance schedule and an attendance book in advance, and manage the state of the visible light receiving terminal 130 described in the attendance book as one of an attendance state, a late state, and an absence state.

The IoT server 100 may determine whether the visible light communication agent 110 and the visible light transmitting device 120 are operating and status information. The IoT server 100 is responsible for all attendance management services performed in a building, and one IoT server 100 may be disposed per building. In addition, the IoT server 100 may expand the service scale by communicating with other IoT servers outside through a network such as the Internet or mobile communication.

The visible light communication agent 110 is a component that serves as a gateway in a situation where it is difficult for the IoT server 100 and the visible light receiving terminal 130 to communicate directly, and transmits a message from the IoT server 100 to a visible light transmission device. It is a component that transmits to 120 and transmits a message from the visible light receiving terminal 130 to the IoT server 100. In this case, the visible light communication agent 110 may transmit messages using communication such as Bluetooth, Wi-Fi, or Zigbee.

The visible light communication agent 110 periodically receives a status report message from all the visible light transmission devices 120, 122, 124 in the room at each preset time, and updates the status table to all visible light transmission devices 120, 122 , 124). The visible light communication agent 110 may be disposed one for each room of the building, and may be connected to an external base station to provide a wireless communication service to the visible light receiving terminal 130.

The visible light transmission device 120 is a component that converts messages received from the IoT server 100 through a wired/wireless network into frames for visible light communication and then transmits them to the visible light receiving terminal 130 using visible light. Specifically, the visible light transmission device 120 converts the activation message, the verification request message, and the result message received from the IoT server 100 into an activation frame, a verification request frame, and a result frame, respectively, and then to the visible light receiving terminal 130. send.

The visible light transmission device 120 may be implemented as a lighting device such as LED lighting, and several visible light transmission devices 120 may be provided for each room, and simultaneously perform the role of lighting and communication. When the visible light transmitting device 120 serves as an illumination, it transmits an IDLE frame to the visible light receiving terminal 130.

The visible light transmission device 120 periodically transmits its status report message to the IoT server 100 or the visible light communication agent 110, thereby allowing the IoT server 100 or the visible light communication agent 110 to manage itself. To be able to do it.

The visible light receiving terminal 130 is a component that receives several frames from the visible light transmission device 120, transmits an attendance confirmation request message to the IoT server 100, and performs a verification process with the IoT server 100. , Depending on the service type, it may be fixed in a specific place or implemented by a smart phone, a PC, a laptop, etc.

The visible light receiving terminal 130 includes a timer therein, and when a response frame for a message transmitted to the IoT server 100 is not received within a preset time, the message may be retransmitted. In this regard, it will be described in detail in FIG. 6.

In transmitting the attendance confirmation request message, the visible light receiving terminal 130 transmits it to the IoT server 100 using a wired or wireless network, or transmits it to the visible light communication agent 110 using wireless communication such as Wi-Fi, or performs visible light communication. It can be transmitted to the visible light transmission device 120 by using. When the visible light transmitting device 120 receives a message from the visible light receiving terminal 130, it transmits the message to the IoT server 100 or the visible light communication agent 110.

Hereinafter, an attendance schedule and an attendance unit stored by the IoT server 100 will be described.

Table 1 is a table illustrating an attendance schedule for reference when the IoT server 100 generates an activation message.

School Name Location Days Approval Late A B1-room1 Mon, Tue 08:00~08:15 08:15~11:30 B B1-room2 Mon-Fri 10:00~10:15 10:15~15:30 C B1-room3 Mon, Fri 13:00~13:15 13:15~16:30 Company Name Location Days Approval Late D B2-room1 Mon-Fri 09:00~09:15 09:15~18:00 E B2-room2 Mon-Fri 10:00~11:00 11:00~18:00

Referring to Table 1, the attendance schedule stores schedules according to classes of schools or departments of companies, and for each schedule, name, location, date, approval, and tardy. Includes the processing period (late).

For example, in the school's attendance schedule, three courses with class names A, B, and C are listed, and class A is taught at B1-room1, room 1 in building B1, and class B and C. Are B1-room2 and B1-room3, respectively. Attendance recognition period may be set to 15 minutes from the start time of class, and late processing period may be set to 15 minutes from the end of the attendance recognition period.

Table 2 is a table illustrating an attendance unit for the IoT server 100 to manage the attendance of the visible light receiving terminal 130 for one schedule.

A Client ID Client Name State 220889 X Approval 203392 Y Approval 920192 W Late 348391 Z X

Referring to Table 2, the attendance for subject A includes client identification information (Client ID), client name (Client Name), and state (State) for each student. The state of attendance is stored as one of an attendance state (approval), a late state (late), and an absence state (X). On the other hand, the attendance book exists as many as a certain number included in the attendance schedule.

1, Tables 1 and 2, the IoT server 100 generates an activation frame and transmits it to the visible light transmission device 120 when the date of each schedule and the start time of the attendance recognition period are reached according to the attendance schedule. . When receiving the attendance request confirmation message from the visible light receiving terminal 130 within the attendance recognition period, the IoT server 100 processes the state of the visible light receiving terminal 130 of the attendance unit as an attendance state. On the other hand, when the IoT server 100 receives the attendance request confirmation message from the visible light receiving terminal 130 during the late processing period, it is stored in the attendance unit in a late state, and if it is not received until the late processing period has elapsed, it is stored as an absence. do.

The IoT server 100 according to an embodiment of the present invention receives the verification request message rather than the attendance request confirmation message from the visible light receiving terminal 130, and the attendance unit according to the reception time of the attendance request confirmation message only after the verification process is completed. The state of the visible light receiving terminal 130 may be stored.

On the other hand, IoT technologies are currently ITU-T, ISO/IEC, oneM2M. Standardization is in progress by various official standardization organizations such as OCF, among which oneM2M stands for IoT service platform standard technology. The oneM2M standard is an AE (Application Entity) that provides application logic for end-to-end IoT communication, CSE (Common Service Entity) consisting of functions that can use various AEs of IoT in common, and a network service to CSE. It includes a Network Service Entity (NSC) that provides.

Hereinafter, a standard applicable to the attendance management system according to an embodiment of the present invention will be described.

In oneM2M, devices are expressed as nodes and are implemented through necessary components according to their role. IN (Infrastructure Node) is a node that provides things communication services in the network infrastructure and is implemented through CSE, and MN (Middle Node) is a node that acts as a gateway connecting device nodes and network infrastructure. Included and implemented. ADN (Application Dedicated Node) is a node representing a resource-constrained device and is implemented through AE.

According to an embodiment of the present invention, the IoT server 100 may be implemented as IN-CSE to provide an attendance management service, and the visible light communication agent 110 includes the IoT server 100 and the visible light transmission device 120 ) Can be implemented as MN-CSE to serve as a gateway between. The visible light transmission device 120 may be implemented as an AND-AE in order to implement only a limited function of converting a message into a frame and transmitting a status report message.

2 is a diagram for explaining a frame structure used for visible light communication according to an embodiment of the present invention.

Referring to FIG. 2, a frame used for visible light communication includes visible light transmission device identification information 200, frame type 210, frame state 220, random number 230, and visible light receiving terminal identification information 240. .

The visible light transmission device identification information 200 is an area used by the IoT server 100 or the visible light communication agent 110 to identify the visible light transmission device 120, and uses 4 bytes to express it in the form of a resource according to the IoT standard. do. The visible light receiving terminal 130 may inform the IoT server 100 of the location of its own building and room by using the visible light transmitting device identification information 200.

The frame type 210 uses 1 byte as an area for classifying the type of visible light communication frame.

The frame state 220 is an area used by the visible light transmitting device 120 to transmit the attendance result to the visible light receiving terminal 130 in the result frame, and uses 1 byte. The resulting status is divided into attendance status (Approval), late status (Late), and absence status (X). The frame state 220 according to an embodiment of the present invention may further include a redundant state, and when the visible light receiving terminal already stored in the attendance state in the attendance unit transmits an attendance request confirmation message to the IoT server It is possible to inform the visible light receiving terminal that it is in a redundant state.

The random number 230 refers to a 4-byte value randomly generated by the IoT server 100, and the IoT server 100 verifies the random number 230 to verify the irregular attendance of the visible light receiving terminal 130. It is included in and transmitted to the visible light receiving terminal 130, and it is checked whether a random number is included in the reply message of the visible light receiving terminal 130.

The visible light receiving terminal identification information 240 is an area for determining whether the visible light receiving terminal 130 transmits a verification request frame and a result frame transmitted from the visible light transmitting device 120 to itself, and uses 10 bytes.

Table 3 is a table showing fields used according to frame types.

Frame Type Field Type State Random number Client ID IDLE 0 Not used Not used Not used ACTIVE One Not used Not used Not used VERIFY 2 Not used Used Used RESULT 3 Used Not used Used

Referring to Table 3, the types of frames transmitted from the visible light transmitting device 120 to the visible light receiving terminal 130 are IDLE frames, activation frames, VERIFY frames, and result frames. It is divided into (RESULT frame).

Idle frames are used to simply serve as lighting when attendance service is not activated. The visible light receiving terminal 130 does not take any action upon receiving this frame.

The activation frame serves to inform the visible light receiving terminal 130 that the attendance management service is activated. When the visible light receiving terminal 130 receives this frame, it transmits an attendance request confirmation message to the IoT server 100.

The verification request frame is used by the IoT server 100 to verify when the visible light receiving terminal 130 transmits the attendance confirmation request message in an illegal manner. When the IoT server 100 receives the attendance confirmation request message from the visible light receiving terminal 130, it generates and matches the identification information of the visible light receiving terminal 130 and a randomly generated random number, and then a verification request message. And transmitted to the visible light transmitting device 120. If the visible light receiving terminal 130 attempts to attend unauthorized attendance at a location other than the service location, the verification request frame may not be received, and thus the irregular attendance may be verified.

The result frame is used by the IoT server 100 to notify the visible light receiving terminal 130 of the status of the attendance unit. The visible light receiving terminal 130 may receive the result frame and check the attendance status.

3 is a diagram exemplified to explain the server and the client side of the attendance management system according to an embodiment of the present invention.

Referring to FIG. 3, the server 300 includes an IoT server, a visible light communication agent, and a visible light transmitting device, and the client 310 includes a visible light receiving terminal.

When the attendance service is not activated, the visible light transmitter serves only as a general lighting and transmits an IDLE frame.

Steps S300 to S304 are a process in which the client 310 transmits an attendance confirmation request message within the attendance recognition period, and the processes S306 to S310 are a process in which the client 310 transmits an attendance confirmation request message within the late processing period.

When the time according to the attendance schedule comes, the server 300 activates the attendance management service and transmits an activation frame to the client 310 (S300).

When the client 310 receives the activation frame, the visible light transmitting device identification information and its own identification information included in the activation frame are included in the attendance request message, and then the attendance confirmation request message is transmitted to the server 300 Do (S302).

When the server 300 receives the attendance confirmation request message within the attendance recognition period, it determines that the client 310 is in the attendance state, and transmits the result frame to the client 310 (S304).

On the other hand, when the server 300 receives the attendance confirmation request message, which is a response to the activation message, during the late processing period (S306), the server 300 transmits a result frame informing the client 310 that the late processing has been performed (S308). .

After the late processing period has elapsed, the server 300 stores the state of the visible light receiving terminal that has not transmitted the attendance confirmation request until the late processing period as an absence, and transmits an idle frame as general lighting to the client 310 (S310). ).

4 is a diagram illustrating a protocol stack structure used in an attendance management system according to an embodiment of the present invention.

Referring to FIG. 4, there is shown a protocol stack structure used for downlink and uplink of an IoT server, a visible light communication agent, a visible light transmitting device, and a visible light receiving terminal.

For communication between the IoT server and the visible light communication agent, either HTTP or CoAP may be used depending on the network situation, and Ethernet may be used when the physical distance between the IoT server and the visible light communication agent is long.

The visible light communication agent uses MQTT to efficiently communicate with all visible light transmission devices managed by it, and since the two entities are generally located at close distances, short-range wireless communication such as Wi-Fi, Bluetooth, or Zigbee can be used.

The visible light receiving terminal may receive a message from the server side through visible light communication, and may transmit an attendance confirmation request message to the server side using HTTP or CoAP.

Table 4 is a table for explaining the types of messages used in the attendance management system.

Message From To Object Entire VT IS VA Configure VLC Frame of All VTs Specific VT IS VA Configure VLC Frame of Specific VT Attendance Request VR IS Request Attendance Verification Request VR IS Request Verification for Correct Way Register VA, VT IS, VA Register Resource for IoT Heartbeat VT VA Report VT State State Check IS VA Register Resource for IoT

Referring to Table 4, Entire VT is an activation message sent by the IoT server to the visible light communication agent, and the visible light communication agent delivers the activation message to all visible light transmission devices managed by the IoT server, and the visible light transmission device is sent to the visible light receiving terminal. Transmit an activation frame.

Specific VT refers to a verification request message or result message transmitted by the IoT server to a visible light communication agent, and the visible light communication agent receiving the same transmits a verification request frame or result frame to a specific visible light receiving terminal.

The Attendance Request message is an attendance confirmation request message transmitted to the IoT server after the visible light receiving terminal receives the activation frame, and includes location information, identification information, and identification information of the visible light receiving terminal. Upon receiving this message, the visible light communication agent adds its own location information and delivers it to the IoT server, and the IoT server identifies the visible light receiving terminal through this.

The Verification Request message is a message used to verify that the visible light receiving terminal has a legitimate attendance status by returning the random number included in the verification request frame to the IoT server. The IoT server determines whether the visible light receiving terminal is properly present by using the random number included in the verification request message and the identification information of the visible light receiving terminal.

Heartbeat message is a status report message for the visible light transmitting device to periodically report its status to the visible light communication agent.

The State Check message is a status check message sent by the IoT server to the visible light communication agent to inquire the state of all visible light transmission devices managed by the visible light communication agent.

The Register message is a registration request message used for each component to register its own resources in the IoT environment.

5 is a diagram illustrating an initial operation of the attendance management system according to an embodiment of the present invention.

Referring to FIG. 5, when power is supplied, the IoT server 100 creates a resource for communicating with other components and checks the attendance schedule to generate an activation message (S500, S502, S504).

When power is supplied, the visible light communication agent 110 searches for the IoT server 100 and registers its own resource in the IoT server 100 (S506, S508).

When power is supplied, the visible light transmission device 120 searches for the visible light communication agent 110, registers its own resource with the visible light communication agent 110, and prepares idle frames (S514 and S518).

Upon receiving the registration request message from the visible light transmission device 120, the visible light communication agent 110 registers the visible light transmission device 120 and transmits the registration request message to the IoT server 100 so that the IoT server 100 To register (S516).

6 is a diagram illustrating an operation process of the attendance management system according to an embodiment of the present invention.

6, steps S612, S628, and S642 will be separately described later. The IoT server 100 transmits an activation message (Entire VT) to the visible light communication agent 110 according to the attendance schedule (S600). The IoT server 100 may transmit directly to the visible light transmission device 120.

The visible light communication agent 110 transmits an activation message to the visible light transmission device 120 (S604).

The visible light transmitting apparatus 120 converts the activation message into an ACTIVE frame, and transmits the activation frame to the visible light receiving terminal 130 using visible light communication (S606, S608).

Upon receiving the activation frame, the visible light receiving terminal 130 generates an attendance request message including its own identification information and transmits it to the visible light communication agent 110 (S610). The visible light receiving terminal 130 may directly transmit an attendance confirmation request message to the IoT server 100.

The visible light communication agent 110 transmits an attendance confirmation request message to the IoT server 100 (S614).

The IoT server 100 determines whether the identification information of the visible light receiving terminal 130 included in the attendance confirmation request message exists in the attendance unit according to the attendance schedule, and if so, generates a random number (S616). . The IoT server 100 generates a verification request message including a random number.

The IoT server 100 transmits or directly transmits the verification request message to the visible light transmission device 120 through the visible light communication agent 110 (S618 and S620).

The visible light transmission device 120 converts the verification request message into a verification request frame (VERIFY frame), and transmits the verification request frame to the visible light receiving terminal 130 using visible light communication (S622, S624).

After extracting the random number included in the verification request frame, the visible light receiving terminal 130 generates a verification request message including its identification information and the random number, and sends it to the IoT server 100 through a visible light communication agent. Transmission or direct transmission (S626, S630).

The IoT server 100 verifies whether the random number included in the verification request message matches the random number included in the verification request message, and the identification information of the visible light receiving terminal 130 included in the verification request message is included in the verification request message. Verify that it matches the identification information. In addition, the IoT server 100 checks whether the visible light receiving terminal 130 is in a proper attendance state, and if the attendance confirmation request message is received during the attendance recognition period, the state of the visible light receiving terminal 130 of the attendance unit is processed as an attendance state. Do (S632). On the other hand, the IoT server 100 stores the attendance confirmation request message as a late state in the attendance section if it is received during the late processing period, and stores it as an absence state if it is not received until the late processing period has elapsed.

The IoT server 100 transmits or directly transmits the result message to the visible light transmitting device 120 through the visible light communication agent 110 (S634 and S636).

The visible light transmitter 120 converts the result message into a RESULT frame, and transmits the result frame to the visible light receiving terminal 130 using visible light communication (S638, S640). The visible light receiving terminal 130 may check the status of its own attendance part included in the result frame.

Hereinafter, a process of retransmitting a message by the visible light receiving terminal 130 (S612, S628, and S642) will be described.

After receiving the activation frame, the visible light receiving terminal 130 sets a timer, and when the verification request frame cannot be received within a preset time, retransmits the attendance confirmation request message to the IoT server 100 (S612). When receiving the verification request frame within a preset time, the visible light receiving terminal 130 resets the timer (S628). In this case, the visible light receiving terminal 130 may transmit to the IoT server 100 through the visible light communication agent 110.

When the visible light receiving terminal 130 does not receive the result frame within a preset time after receiving the verification request frame, it retransmits the verification request message to the IoT server 100. When receiving the result frame within a preset time, the visible light receiving terminal 130 stops the timer (S640). In this case, the visible light receiving terminal 130 may transmit to the IoT server 100 through the visible light communication agent 110.

The attendance management system according to an embodiment of the present invention may omit steps S616 to S632 for speed. The visible light receiving terminal 130 may transmit an attendance confirmation request to the IoT server 100 immediately after receiving the activation frame. The IoT server 100 may transmit a result message to the visible light transmission device 120 even if the verification process is not performed. Similarly, when the IoT server 100 receives the attendance confirmation request message during the attendance recognition period, it stores the state of the visible light receiving terminal 130 written in the attendance book as an attendance state, and when received during the tardy processing period, stores the state of the visible light reception terminal 130 as an attendance state, If it is not received until the late processing period has passed, it is stored as absent.

7 is a view for explaining a periodic status check of a visible light transmission device in the attendance management system according to an embodiment of the present invention.

Referring to FIG. 7, the visible light communication agent 110 executes a timer for checking the state of the visible light transmission device 120 after an initialization process (S700).

The visible light transmission device 120 periodically transmits a heartbeat message to the visible light communication agent 110 at predetermined time intervals (S702).

When the visible light communication agent 110 receives the status report message from the visible light transmission device 120, it updates the previously stored status table and restarts the timer (S704). Here, the state table refers to a table including identification information and a registered state of the visible light transmitting apparatus 120. The visible light communication agent 110 may periodically check the state of the visible light transmission device 120 by managing the state table of the visible light transmission device 120.

The IoT server 100 transmits a status confirmation message to the visible light communication agent 110 in order to check the status of the visible light communication agent 110 and the visible light transmission device 120 (S708).

The visible light communication agent 110 transmits its identification information and status to the IoT server 100 together with a status table for the visible light transmission device 120 (S708). Through this, the IoT server 100 may check the state of the visible light communication agent 110 and the visible light transmission device 120.

On the other hand, when the visible light transmission device 120 does not operate due to a temporary failure, etc. (S710), the visible light communication agent 110 executes a timer and then sends a status report message from the visible light transmission device 120 within a preset time. If not, the state and registration information of the visible light transmission device 120 described in the state table are deleted (S712).

3, 5, 6, and 7 describe sequentially executing steps S300 to S712, this is merely illustrative of the technical idea of an embodiment of the present invention. In other words, those of ordinary skill in the technical field to which an embodiment of the present invention belongs can change the order shown in FIGS. 3, 5, 6 and 7 without departing from the essential characteristics of an embodiment of the present invention. 6 is not limited to a time-series order by executing or executing one or more of the processes S300 to S712 in parallel, so that various modifications and variations may be applied.

Meanwhile, the processes shown in FIGS. 3, 5, 6, and 7 can be implemented as computer-readable codes on a computer-readable recording medium. The computer-readable recording medium includes all types of recording devices that store data that can be read by a computer system. That is, such a computer-readable recording medium may be a non-transitory medium such as ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage device, etc., and may also be a carrier wave (for example, , Transmission via the Internet) and a data transmission medium may further include a transitory medium. In addition, the computer-readable recording medium can be distributed over a computer system connected through a network to store and execute computer-readable codes in a distributed manner.

The above description is merely illustrative of the technical idea of the present embodiment, and those of ordinary skill in the technical field to which the present embodiment belongs will be able to make various modifications and variations without departing from the essential characteristics of the present embodiment. Accordingly, the present exemplary embodiments are not intended to limit the technical idea of the present exemplary embodiment, but are illustrative, and the scope of the technical idea of the present exemplary embodiment is not limited by these exemplary embodiments. The scope of protection of this embodiment should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present embodiment.

100: IoT server 110: visible light communication agent
120: visible light transmitting device 130: visible light receiving terminal

Claims (16)

In the method of operating an attendance management system using visible light communication (VLC),
An IoT server (IS) transmitting an activation message to a visible light transmitter (VT) according to the attendance schedule;
Converting the activation message into an ATCTIVE frame by the visible light transmitting apparatus and transmitting the activation frame to a visible light receiving terminal (VLC receiver, VR) using visible light communication;
Transmitting, by the visible light receiving terminal, an attendance confirmation request message including its own identification information to the IoT server;
When the IoT server receives the attendance confirmation request message within the attendance recognition period, storing the state of the visible light receiving terminal of the attendance unit as an attendance state, and transmitting a result message to the visible light transmitting device; And
Converting, by the visible light transmission device, the result message into a RESULT frame and transmitting the result frame to a visible light receiving terminal;
Operating method of the attendance management system comprising a. The method of claim 1,
Transmitting a verification request message including a random number randomly generated by the IoT server receiving the attendance verification request message to the visible light transmitting device;
Converting, by the visible light transmission device, the verification request message into a verification request frame (VERIFY frame) and transmitting it to a visible light receiving terminal using visible light;
Transmitting, by the visible light receiving terminal, a verification request message including the random number and its own identification information to the IoT server; And
Verifying, by the IoT server, a random number included in the verification request message and identification information of the visible light receiving terminal;
Operation method of the attendance management system further comprising. The method of claim 2,
When the visible light receiving terminal does not receive the verification request frame within a preset time after receiving the activation frame, retransmitting the attendance confirmation request message to the IoT server
Operation method of the attendance management system further comprising. The method of claim 2,
The process of retransmitting the verification request message to the IoT server when the visible light receiving terminal does not receive the result frame within a preset time after receiving the verification request frame
Operation method of the attendance management system further comprising. The method of claim 1,
When the IoT server receives the attendance confirmation request message within a late processing period, storing the state of the visible light receiving terminal of the attendance unit as a late state, and transmitting a result message to the visible light transmitting device
Operation method of the attendance management system further comprising. The method of claim 1,
The process of transmitting an IDLE frame to the visible light receiving terminal before the visible light transmitting device receives the activation frame
Operation method of the attendance management system further comprising. The method of claim 1,
Registering the visible light receiving terminal with a visible light communication agent (VLC agent, VA); And
Registering by the visible light communication agent in the IoT server;
Including more,
The visible light communication agent transmits the message of the IoT server to the visible light transmitting device, and transmits the message of the visible light receiving terminal to the IoT server. The method of claim 7,
The process of updating a status table when the visible light communication agent receives a status report message from the visible light transmission device at a preset time, and deleting registration information of the visible light transmission device from the status table when the status report message is not received
Operation method of the attendance management system further comprising. In the attendance management system using visible light communication,
An IoT server that generates an activation message according to the attendance schedule and generates a result message when an attendance confirmation request message is received within the attendance recognition period;
A visible light transmitting device that converts the activation message and the result message generated by the IoT server into an activation frame and a result frame, respectively, and transmits it using visible light communication; And
A visible light receiving terminal for transmitting an attendance confirmation request message including its own identification information to the IoT server upon receiving the activation frame;
Attendance management system comprising a. The method of claim 9,
After receiving the attendance confirmation request message, the IoT server stores the state of the visible light receiving terminal of the attendance unit as an attendance state, and converts a verification request message including a random number into a verification request frame using the visible light transmission device. Then, the attendance management system is transmitted to the visible light receiving terminal, and verifies attendance of the visible light receiving terminal by using a random number and identification information included in a verification request message received from the visible light receiving terminal. The method of claim 10,
The visible light receiving terminal,
When the verification request frame is not received within a preset time after receiving the activation frame, the attendance management system retransmits the attendance confirmation request message to the IoT server. The method of claim 10,
The visible light receiving terminal,
An attendance management system for retransmitting the verification request message to the IoT server when the result frame is not received within a preset time after receiving the verification request frame. The method of claim 9,
The IoT server,
When the attendance confirmation request message is received within a late processing period, the attendance management system stores the state of the visible light receiving terminal of the attendance unit as a late state and transmits a result message to the visible light transmission device. The method of claim 9,
The visible light transmission device,
Attendance management system for transmitting an idle frame to the visible light receiving terminal before receiving the activation frame. The method of claim 9,
Further comprising a visible light communication agent for transmitting the message of the IoT server to the visible light transmitting device, and transmitting the message of the visible light receiving terminal to the IoT server,
An attendance management system in which the visible light receiving terminal is registered with the visible light communication agent, and the visible light communication agent is registered with the IoT server. The method of claim 15,
The visible light communication agent,
An attendance management system for updating a pre-stored state table when a status report message is received from the visible light transmission device at every preset time, and deleting registration information of the visible light transmission device from the status table when the status report message is not received.

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