KR20120062129A - Method and system of examination for providing internet protocol television - Google Patents

Abstract

PURPOSE: A verifying method for IPTV(Internet Protocol TV) service supply and a system thereof are provided to confirm service availability and to determine whether to supply an IPTV service according to a confirming result. CONSTITUTION: A VOD(Video On Demand) supplying state determining unit(230) determines whether to supply VOD content of a user terminal. The user terminal is matched with user information. A real time broadcasting supplying state determining unit(240) determines weather to supply real time broadcasting content of the user terminal. A customer information managing unit(250) determines whether to suppy an IPTV service to the user terminal.

Description

Validation method and system for IP service delivery {METHOD AND SYSTEM OF EXAMINATION FOR PROVIDING INTERNET PROTOCOL TELEVISION}

The present invention relates to a method and system for verifying a state for providing an internet protocol TV (IPTV) service, and more particularly, to a method and system for verifying whether IPTV service can be provided in response to a request for providing an IPTV service. .

Recently, according to the development of communication technology and the spread of the use of the Internet, various services using the Internet are provided to users, and in particular, IPTV services providing various contents through the Internet network are widely used.

In general, in order for a user to receive an IPTV service, a service provider who provides the IPTV service needs to open the IPTV service, and an installation agent of the service provider moves directly to the user's home to check the home line of the Internet network, and sets the IPTV set-top. Carry out the wiring of the premises at the location where the box will be installed and connect the IPTV set-top box to the network.

After that, the setting value of the IPTV set-top box is automatically or manually inputted, and after the terminal is authenticated by the IPTV service management server, the installation agent who confirms that the VOD service and the real-time broadcasting service operates normally reports the opening completion. After notifying the service manager, the IPTV service is provided to the user.

According to this conventional procedure, since the installation personnel must be dispatched to the user's place of residence in order to process the work according to the user's IPTV service request, human resources are consumed, and the user is also large as external personnel perform various tasks in the place of residence. There was a problem of experiencing a small inconvenience.

In addition, even if the service provider is unable to provide IPTV service to the user's residence because of a problem in the network state and content provision state after the installation agent dispatched, there is a problem that wastes the costs associated with the dispatch of the installation agent insignificantly there was.

An embodiment of the present invention is to determine the availability of the service by determining the network state, VOD or the provision of the real-time broadcast content, such as a separate manpower to provide the IPTV service to the user without having to go to the user's residence, and as a result In accordance with the present invention, a system and method for determining whether to provide an IPTV service are provided.

As a technical means for achieving the above-described technical problem, the first aspect of the present invention is (a) receiving an IPTV service provision request signal including user information, (b) the state of the network matching the user information is Determining whether the internet service can be provided; (c) if the network state corresponding to the user information is a state capable of providing an IPTV service, a video on demand for a user terminal matching the user information; VOD) determining whether the content providing state is a state capable of providing IPTV service, (d) when the VOD providing state for the user terminal is in a state capable of providing IPTV service, the real time broadcasting content providing state for the user terminal is IPTV Determining whether the service can be provided; and (e) real time for the user terminal. When the broadcast content provision state is the IPTV service provision state, the IPTV service verification server may include providing a method for verifying the IPTV service, including providing the IPTV service to the user terminal.

In the first aspect of the present invention, the step (b) may include (b1) transmitting a network state determination signal to network equipment matching the user information, and (b2) corresponding to the network state determination signal from the network equipment. Receiving network state information, and determining whether a state of a network matching the user information is a state capable of providing an Internet service, based on the received network state information; and (b3) the network state information and the state of the network. And storing a result of determining whether the internet service is available or not by matching the user information, and the network state information may include information of a network speed of the network equipment.

In the first aspect of the present invention, the step (c) is (c1) transmitting a VOD provision state determination signal to the user terminal, (c2) a VOD provision state corresponding to the VOD provision state determination signal from the user terminal Receiving information, and determining whether the state of the user terminal and the network connected to the user terminal is capable of providing VOD content based on the received VOD providing state information; and (c3) the VOD providing state information and the VOD. And storing the result of determining whether the content can be provided in accordance with the user information, wherein the VOD providing state information includes at least one of VOD output state information, connection state information with a server providing VOD content, and download bandwidth information of VOD content. It can contain one piece of information.

In the first aspect of the invention, the step (d) is (d1) transmitting a real time broadcast providing status determination signal to the user terminal, (d2) a real time corresponding to the real time broadcast providing status determination signal from the user terminal Receiving provision status information, and determining whether a status of the user terminal and a network connected to the user terminal is capable of providing real-time broadcasting content based on the received real-time broadcasting provision status information; and (c3) the real-time broadcasting. And matching and storing provision state information and a determination result of provision of real-time broadcast content to the user information, wherein the real-time broadcast provision state information includes real-time broadcast output state information and connection state information with a server providing real-time broadcast content. And download bandwidth information of the real-time broadcasting content. Information may include

In addition, the second aspect of the present invention is a network state determination unit for determining whether the Internet service is available for the network matching the user information included in the IPTV service providing request signal, video on demand for the user terminal matching the user information ( video on demand (VOD) content on-demand (VOD) provision state determination unit for determining the availability of the content, real-time broadcast provision state determination unit for determining whether to provide real-time broadcast content to the user terminal and the network Internet protocol TV including a customer information management unit for determining whether to provide IPTV service to the user terminal matching the user information based on the determination of the state determination unit, VOD provision state determination unit and the real-time broadcast provision state determination unit ) Can provide IPTV service verification system have.

According to the above-described problem solving means of the present invention, when the IPTV service provision request from the user occurs, the IPTV service verification server checks the network state, VOD provision state, real-time broadcasting state for the user without a separate installation agent In order to transmit the signal to the network equipment or the set-top box, and receive a response signal thereto, it can be determined whether the IPTV service can be provided based on the received response signal.

According to the above-described problem solving means of the present invention, since there is no separate installation personnel, the IPTV service provider can reduce the cost for providing the IPTV service, the user will not experience the burden of working outside the house Can be.

1 is a diagram illustrating a user terminal and an IPTV service verification server to which an automatic verification system for providing an IPTV service according to an embodiment of the present invention is applied;
2 is a flowchart illustrating a method of performing an automatic verification for providing an IPTV service by an IPTV service verification server according to an embodiment of the present invention;
3 is a diagram illustrating a configuration of an IPTV service verification server of an automatic verification system for providing an IPTV service according to an embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between . In addition, when a part is said to "include" a certain component, which means that it may further include other components, except to exclude other components unless otherwise stated.

1 is a diagram illustrating a user terminal and an IPTV service verification server to which an automatic verification system for providing an IPTV service according to an embodiment of the present invention is applied.

In the IPTV service provision automatic verification system according to an embodiment of the present invention, the user terminal, that is, the set-top box 100 requests verification for providing the IPTV service to the IPTV service verification server 200 through a network.

The set-top box 100 receives a sample signal from the IPTV service verification server 200, that is, a test signal for determining a network state, a video on demand (VOD) output state, and a real-time broadcast output state.

The set-top box 100 tests the basic network connection state, VOD or real-time broadcast output state by using the received sample signal, and transmits a result signal including the result to the IPTV service verification server 200.

The set top box 100 may test the output state by outputting the received sample signal to the display apparatus 10 such as a TV.

The IPTV service verification server 200 receives a verification request signal for providing an IPTV service from the set-top box 100, and in response thereto, outputs a basic network state test signal, a VOD output state test signal, and a real-time broadcast output to the set-top box 100. Status test signals are sequentially transmitted, and the test results for each test signal are received by the set-top box 100 and stored and managed for each user.

When the IPTV service verification server 200 determines that the network state of the set-top box 100 is suitable for providing IPTV service according to the test result of each test signal, the IPTV service verification server 200 is set-top box ( Request the provision of IPTV service.

The IPTV service providing server 300 registers a user of the set-top box 100 and the set-top box 100 in response to a request of the IPTV service verification server 200 and provides a content service to the set-top box 100.

2 is a flowchart illustrating a method of performing an automatic verification for providing an IPTV service by an IPTV service verification server according to an embodiment of the present invention.

In step S105, the IPTV service verification server receives an IPTV service request signal from the user. The IPTV service request signal received by the IPTV service verification server may include information of the user, for example, an address of a place where the user wants to use the IPTV service, and identification information of the user.

A user may transmit an IPTV service request to an IPTV service verification server by using a terminal capable of communicating via the Internet such as a desktop or a notebook as well as a set-top box.

Accordingly, the user may request the IPTV service using a terminal capable of internet communication even before receiving the set-top box, which is a terminal for receiving the IPTV service from the IPTV service provider.

In addition, a user may request IPTV service directly from an IPTV service provider through a telephone. In this case, the IPTV service verification server may receive an IPTV service request signal from the IPTV service provider.

In step S110, the IPTV service verification server transmits a network state determination signal for an address for which the user wants to receive an IPTV service in response to the IPTV service request signal received in step S105, and receives a result signal thereof. do.

That is, the IPTV service verification server is a network connected to the user's residence address, etc., in order to grasp the basic state of the network such as an Internet network connected to the address of the user requesting the IPTV service, for example, the user's residence address. The network status determination signal is transmitted and a response signal is received.

The response signal of the network status determination signal may be generated by a network device allocated to an area where the user who requested the IPTV service is located, and the network device may include a settop-box (STB) of the user.

In general, the network equipment may transmit a response signal to the network status determination signal to the IPTV service verification server through the SNMP protocol using a Simple Network Management Protocol (SNMP) agent.

Simple Network Management Protocol (SNMP) is a protocol that operates based on Transmission Control Protocol / Internet Protocol (TCP / IP) and is a protocol used to remotely monitor and control TCP / IP-based network equipment.

Accordingly, the network equipment may provide the IPTV service verification server with information about the network status connected to the user who applied for the IPTV service using the SNMP protocol in response to the network status determination signal.

The information on the network state may determine whether the network state of the user can normally receive the IPTV service by using data included in the network state determination signal.

For example, the network equipment may transmit a response signal including the OID = 1.3.6.1.4.1.14008.27300.2.3.1.4.1.1 stbSpeedCheck = 1 information of the SNMP protocol to the IPTV service verification server.

In this response signal, 'stbSpeedCheck = 1' indicates that the network speed of the user's Internet is more than 14M / bps, and 'stbSpeedCheck = 0' is less than 14M / bps.

In addition, the network equipment can transmit data to the IPTV service verification server by creating IpstbBuildTrap with OID = 1.3.6.1.4.1.14008.27300.2.3.2.2.8 using the SNMP agent. 'IpstbBuildTrap' may include ID information of a terminal, MAC information of a terminal of a terminal, a value of stbSpeedCheck, and information of an IpStbBuildState value.

In step S115, the IPTV service verification server generates network state information based on the response signal to the network state determination signal received in step S110, and generates the IPTV service in step S105. Match and save the requested customer.

In step S120, the IPTV service verification server determines that the basic network state for the user who requested the IPTV service received in step S105 is based on the response signal to the network state determination signal received in step S110. It is determined whether or not the normal state to provide, that is, the Internet service available state.

The IPTV service verification server may analyze the response signal received in step S110 to measure the bandwidth and the like and determine the network state based on the measurement result.

In step S125, if it is determined in step S120 that the basic network status for the user who requested the IPTV service is normal for providing the IPTV service, the IPTV service verification server may include a user terminal of the user who requested the IPTV service; For example, a video on demand (VOD) test signal is sent to a settop-box (STB) and the result signal is received.

The user terminal may check the state of the VOD output through the user terminal, for example, the set-top box, by using the VOD test signal received from the IPTV service verification server.

That is, the set-top box may generate information on the output state of the VOD, the connection state of the VOD content server, the download bandwidth of the content, etc. using the VOD test signal received from the IPTV service verification server.

For example, the set-top box can send an OID = 1.3.6.1.4.1.14008.27300.2.3.1.4.1.1 stbSpeedCheck = 0 response signal of the SNMP protocol to the IPTV service verification server, which is connected to the set-top box. It may indicate that the speed of the network is less than 14M / bps. In addition, the set-top box may not generate 'IpstbBuildTrap' with OID = 1.3.6.1.4.1.14008.27300.2.3.2.2.8 using an SNMP agent unlike in step S110.

In step S130, the IPTV service verification server generates VOD output state information based on the response signal received in step S125, and matches the generated VOD output state information with the user who requested the IPTV service.

In step S135, the IPTV service verification server performs a VOD service state for the user terminal of the user who requested the IPTV service based on the result signal for the VOD test signal received in step S125, that is, the state of the user terminal and the user terminal. It is determined whether the state of the network connected to the network is in a normal state for providing VOD content through the IPTV service.

The IPTV service verification server may determine the VOD service state based on the output state of the VOD, the VOD content server connection state, and the download bandwidth information of the content included in the result signal received in step S125.

In step S140, when it is determined that the VOD service state for the user terminal of the user who requested the IPTV service in step S135 is normal to provide the VOD content, the IPTV service verification server determines that the user requested the IPTV service. A real-time broadcast test signal is transmitted to a user terminal, for example, a settop box (STB), and a result signal thereof is received.

The user terminal may check the state of the real time broadcast output through the user terminal, for example, the set-top box, using the real-time broadcast test signal received from the IPTV service verification server.

That is, the set-top box may generate information about the output state of the real time broadcast, the connection state of the real time broadcast content server, the download bandwidth of the content, etc. using the real time broadcast test signal received from the IPTV service verification server.

For example, the set-top box may send an OID = 1.3.6.1.4.1.14008.27300.2.3.1.4.1.2 stbBuildState = 1 response signal of the SNMP protocol to the IPTV service verification server. In this type of response signal, 'stbBuildState = 1' indicates that the user's multicast join is normal, and 'stbBuildState = 0' indicates that the Internet's multicast join is abnormal. In addition, the user terminal may not generate 'IpstbBuildTrap' with OID = 1.3.6.1.4.1.14008.27300.2.3.2.2.8 using the SNMP agent as in step S125.

In step S145, the IPTV service verification server generates real-time broadcast output state information based on the result signal for the real-time broadcast test signal received in step S140, and requests the IPTV service for the generated real-time broadcast output state information. Match the user and save it.

In step S150, the IPTV service verification server performs a real-time broadcast service on the user terminal of the user terminal of the user who requested the IPTV service based on the result signal for the real-time broadcast test signal received in step S140. It is determined whether the content is in a normal state.

In step S155, if it is determined in step S150 that the real-time broadcasting service state of the user terminal of the user requesting the IPTV service is normal to provide real-time broadcasting content, the IPTV service verification server performs step S105. Registers the IPTV service by matching the user terminal and user of the user requesting the IPTV service, and provides the IPTV service, ie, VOD, real-time broadcasting, etc. to the registered user terminal through an IPTV service provision server (not shown). do.

As described above, in one embodiment of the present invention, the IPTV service verification server sequentially determines the basic network state, VOD service state and real-time broadcast service state for the user who applied for the IPTV service, and the network state and VOD service state. And IPTV service only when both of the real-time broadcasting service state are suitable for providing IPTV service.

In addition, since the IPTV service verification server stores the network state, the VOD service state, and the real-time broadcasting service state test result by matching the user or the user terminal, it is determined whether the IPTV service can be provided for the same region by using the stored data. Network management for providing an IPTV service can be performed.

3 is a diagram illustrating a configuration of an IPTV service verification server of an automatic verification system for providing an IPTV service according to an embodiment of the present invention.

The IPTV service verification server 200 according to an embodiment of the present invention includes a service request receiver 210, a network state determiner 220, a VOD provision state determiner 230, a real-time broadcast provision state determiner 240, And a customer information management unit 250 and a customer information database 260.

The service request receiver 210 receives a request for providing an IPTV service from a user. The service request receiving unit 210 may include the user's information, that is, the address of the place where the user wants to use the IPTV service, identification information of the user, etc. together with the IPTV service provision request.

The network state determination unit 220 may test a basic state of an Internet network connected to an address, for example, a residential address, for which the user wants to receive an IPTV service, in response to the IPTV service provision request received by the service request receiver 210. The network status determination signal is transmitted to a network device in a region where an address for which the user wants to receive IPTV service or a network device connected to a building of an address for which the user wants to receive IPTV service.

The network state determination unit 220 receives a response signal to the network determination signal, that is, a network state result signal, from the network equipment that transmitted the network state determination signal, and receives the received network state result signal through the customer information management unit 250. The customer information database 260 matches and stores the user.

The network state determination unit 220 determines whether the network state for the location where the IPTV service is requested is normal to provide the IPTV service, based on the received network state result signal, and determines the customer information management unit 250. To send).

The video on demand (VOD) provision state determination unit 230 transmits a VOD test signal to a user terminal of the user requesting the IPTV service, that is, a set-top box (STB). The VOD test signal may include the VOD sample signal or access information for accessing the VOD sample data. The set-top box uses the VOD test signal to output the VOD, the VOD content server connection state, and download bandwidth of the content. Can be checked against

The VOD provision state determination unit 230 receives a response signal to the VOD test signal, that is, a VOD provision state result signal, from the set-top box, and receives the received VOD provision state result signal through the customer information manager 250. 260 matches the user and stores the same.

The VOD provision state determination unit 230 determines whether the VOD provision state for the set-top box of the user requesting the IPTV service is normal to provide the IPTV service, based on the received VOD provision state result signal, and the determination result Send to the customer information management unit (250).

The real-time broadcast providing state determiner 240 transmits a real-time broadcast test signal to the set-top box (STB). Like the VOD test signal, the real-time broadcast test signal may include a real-time broadcast sample signal or access information for accessing real-time broadcast sample data. The set-top box uses a real-time broadcast test signal to output an output state and a real time. The connection content of the broadcast content server and the download bandwidth of the content may be checked.

The real-time broadcast provision state determination unit 240 receives a real-time broadcast provision state result signal from the set-top box, and matches the received real-time broadcast provision state result signal to the user information database 260 through the customer information management unit 250. Save it.

The real-time broadcast provision state determination unit 240 determines whether the real-time broadcast provision state for the set-top box of the user who requested the IPTV service on the basis of the received real-time broadcast provision state result signal is normal to provide the IPTV service, The determination result is transmitted to the customer information management unit 250.

The customer information management unit 250 may receive a network status result signal, a VOD provision status result signal, and a real-time broadcast received from the network status determination unit 220, the VOD provision state determination unit 230, and the real-time broadcast provision state determination unit 240, respectively. The status result signal is matched to the user and stored in the customer information database 260.

The customer information management unit 250 determines the network state, the VOD provision state determination result, and the real-time broadcast provision state from the network state determination unit 220, the VOD provision state determination unit 230, and the real-time broadcast provision state determination unit 240, respectively. The determination result is received, and based on the determination result, it is determined whether to provide the IPTV service to the user who requested the IPTV service.

The customer information management unit 250 registers the IPTV service for the user who is suitable for providing the IPTV service in the network state, the VOD provision state, and the real-time broadcast provision state, and provides the IPTV service to the user terminal. Information of the user and the user terminal may be transmitted to a service providing server (not shown).

Accordingly, a user terminal suitable for a network state, a VOD provision state, and a real-time broadcast provision state may receive the content from the IPTV service provision server and output the provided content to the user.

One embodiment of the present invention may also be embodied in the form of a recording medium including instructions executable by a computer, such as program modules, being executed by a computer. Computer readable media can be any available media that can be accessed by a computer and includes both volatile and nonvolatile media, removable and non-removable media. In addition, computer readable media may include both computer storage media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Communication media typically includes computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave, or other transmission mechanism, and includes any information delivery media.

While the methods and systems of the present invention have been described in connection with specific embodiments, some or all of those elements or operations may be implemented using a computer system having a general purpose hardware architecture.

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

100: set-top box (STB) 200: IPTV service verification server
210: service request receiving unit 220: network state determination unit
230: VOD provision state determination unit 240: Real-time broadcast provision state determination unit
250: customer information management unit 300: IPTV service providing server

Claims (8)

In the method of the IPTV (Internet protocol TV) service verification server to verify the IPTV service,
(a) receiving a request signal for providing an IPTV service including user information;
(b) determining whether a state of the network matching the user information is in a state of providing Internet service;
(c) if the state of the network matching the user information is in a state capable of providing an IPTV service, whether a video on demand (VOD) content provision state of a user terminal matching the user information is in a state capable of providing an IPTV service; Determining whether or not,
(d) when the VOD provision state for the user terminal is in a state capable of providing an IPTV service, determining whether the real time broadcasting content provision state for the user terminal is in a state capable of providing an IPTV service; and
(e) starting to provide an IPTV service to the user terminal when the real time broadcasting content provision state for the user terminal is available to provide an IPTV service;
IPTV service verification method comprising a.
The method of claim 1,
In step (b),
(b1) transmitting a network state determination signal to network equipment matching the user information;
(b2) receiving network state information corresponding to the network state determination signal from the network equipment, and determining whether the state of the network matching the user information is a state of providing Internet service based on the received network state information; Steps and
(b3) storing the network state information and a result of determining whether the state of the network is capable of providing an Internet service to the user information;
Including,
Wherein the network state information includes information of network speed for the network equipment.
The method of claim 1,
In step (c),
(c1) transmitting a VOD provision state determination signal to the user terminal;
(c2) receiving VOD providing state information corresponding to the VOD providing state determination signal from the user terminal, and providing the VOD content with the state of the user terminal and the network connected to the user terminal based on the received VOD providing state information; Determining whether it is in a possible state; and
(c3) storing the VOD providing state information and the result of determining that the VOD content can be provided in accordance with the user information
Including,
The VOD providing status information includes at least one of VOD output status information, connection status information with a server providing VOD content, and download bandwidth information of VOD content.
The method of claim 1,
In step (d),
(d1) transmitting a real time broadcast providing state determination signal to the user terminal;
(d2) receiving real time provision state information corresponding to the real time broadcast provision state determination signal from the user terminal, and based on the received real time broadcast provision state information, the state of the user terminal and a network connected to the user terminal is real time; Determining whether the broadcast content can be provided; and
(c3) storing the real-time broadcasting providing state information and the result of determining whether the real-time broadcasting contents can be provided in correspondence with the user information and storing the same;
Including,
The real time broadcast providing state information includes at least one of real time broadcast output state information, connection state information with a server providing real time broadcast content, and download bandwidth information of the real time broadcast content.
In the IPTV service verification system for providing an IPTV (internet protocol TV) service,
A network state determination unit that determines whether Internet service is available for a network matching user information included in an IPTV service request signal;
Video on demand (VOD) provision state determination unit for determining whether to provide video on demand (VOD) content for the user terminal matching the user information,
A real-time broadcast provision state determination unit to determine whether real-time broadcast content can be provided to the user terminal;
A customer information management unit that determines whether to provide an IPTV service to a user terminal matching the user information based on the determination of the network state determination unit, the VOD provision state determination unit, and the real-time broadcast provision state determination unit.
IPTV service verification system comprising a.
The method of claim 5, wherein
The network state determination unit determines whether the Internet service is available based on the network state information received from the network equipment matching the user information, wherein the network state information includes the information of the network speed for the network equipment IPTV Service Verification System.
The method of claim 5, wherein
The VOD provision state determination unit determines whether VOD content can be provided based on the VOD provision state information received from the user terminal, and the VOD provision state information includes VOD output state information and connection state information with a server providing VOD content. And download bandwidth information of the VOD content.
The method of claim 5, wherein
The real-time broadcast providing state determination unit determines whether the real-time broadcast content can be provided based on the real-time broadcast providing state information received from the user terminal, the real-time broadcast providing state information is a server for providing real-time output state information, real-time broadcast content IPTV service verification system comprising at least one of the connection state information and the download bandwidth information of the real-time broadcast content.

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