KR20130048457A - Server and method for managing contents to be distributed to cache device, and the cache device - Google Patents

Abstract

PURPOSE: A server for managing content distributed to a cache device in advance, a method thereof, and the cache device thereof are provided to distribute content in advance by determining the cache device distributing the content based on a monitoring result. CONSTITUTION: A monitoring unit(14) receives monitoring result data from a first cache device monitoring content used by a terminal. A cache device management unit(13) determines a second cache device requiring the advance distribution of the content. A control signal generating unit(12) generates a control signal notifying the advance distribution of the content. A control signal transmitting unit(11) transmits the generated control signal to the second cache device. [Reference numerals] (11) Control signal transmitting unit; (12) Control signal generating unit; (13) Cache device management unit; (14) Monitoring unit; (15) Storage; (16) Notification signal transmitting unit; (41) Network

Description

TECHNICAL FIELD [0001] The present invention relates to a server and a method for managing contents to be pre-distributed to a cache apparatus,

And more particularly, to a server and method for managing contents to be pre-distributed to a cache apparatus, and a cache apparatus.

Users having devices such as a smart phone can receive multimedia data, that is, contents such as music, images, and the like, as well as accessing and downloading Internet web pages, as well as sharing voice conversations. As the number of users of these devices increases, there is a growing need to provide substantial data to users. In addition, as the size of the terminals is reduced, it is convenient to carry the terminals. In connection with a method of delivering content based on location to a mobile device, Korean Unexamined Patent Publication No. 2008-0110593 discloses a method for dynamically providing content related to the location of a mobile device moving in a wireless communication network have.

On the other hand, the N Screen (Screen) service is a service that allows the user to use the service that was independently used in various devices, such as TV, PC, tablet PC or smart phone in a complex way. In such a N screen service, a technology of simultaneously playing the same content on a plurality of devices of various types and a technology of continuously playing content played on any one terminal of a plurality of devices on a plurality of other devices, etc. Is required.

A server and a method for distributing content in advance by determining a cache apparatus that monitors content used by the terminal and pre-distributes the content based on the monitored result, and a cache apparatus that provides the distributed content to a plurality of terminals do. It is to be understood, however, that the technical scope of the present invention is not limited to the above-described technical problems, and other technical problems may exist.

As a technical means for achieving the above technical object, an embodiment of the present invention provides a content distribution system including a monitoring unit for receiving monitoring result data from a cache apparatus for monitoring content used by a terminal, A management server including a cache apparatus management unit for determining a cache apparatus, a control signal generation unit for generating a control signal for notifying the pre-distribution of contents, and a control signal transmission unit for transmitting a control signal to a cache apparatus at a different position from the cache apparatus .

According to an embodiment of the present invention, there is provided a method of monitoring a cache apparatus, the method comprising: receiving monitoring result data of a content used by a terminal from a cache apparatus among a plurality of cache apparatuses; A control signal transmission method including a step of determining a cache device, a step of generating a control signal indicating pre-distribution of the content, and a step of transmitting a control signal generated in the cache device.

In addition, in one embodiment of the present invention, a content monitoring unit for monitoring content used by at least one terminal connected through a network, a result data transmitting unit for generating monitoring result data, and transmitting the generated result data to a management server, A control signal receiving unit for receiving a control signal informing pre-distribution of the external content monitored by the external cache apparatus existing at a different position from the cache apparatus from the management server, a control signal receiving unit for obtaining the external content based on the received control signal, And a content processing unit for storing external contents.

According to any one of the above objects of the present invention, there is provided a server and a method for distributing a content in advance by determining a cache apparatus that monitors content used by the terminal and pre-distributes the content based on the monitored result, And a cache apparatus that provides distributed content to a plurality of terminals. In addition, it is possible to provide a quick response time and a high-quality content service to a terminal moving to another area covered by one cache device in the area occupied by one cache device.

1 is a diagram of a content pre-distribution system in accordance with an embodiment of the present invention.
2 is a configuration diagram of the management server shown in FIG.
3 is a diagram illustrating a process in which data is transmitted and received between each member included in the content pre-distribution system of FIG. 1 according to an embodiment of the present invention.
FIG. 4 is a configuration diagram of one of the plurality of cache devices shown in FIG. 1 according to an embodiment of the present invention.
5 is a service flow diagram according to an embodiment of the present invention.
6 is a flow diagram illustrating a content pre-distribution method according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. However, the present invention may be modified into various different forms and is not limited to the embodiments described 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.

When a part is referred to as being "connected" to another part throughout the specification, it includes not only "directly connected" but also "electrically connected" between other parts in between. Also, when an element is referred to as "comprising ", it means that it can include other elements, not excluding other elements unless specifically stated otherwise.

1 is a diagram of a content pre-distribution system in accordance with an embodiment of the present invention. 1, a contents dictionary distribution system is connected to a management server 10, a plurality of cache devices 20 to 22, and a plurality of cache devices 20 to 22 are connected to a plurality of terminals 300 through a network do.

A network refers to a connection structure in which information can be exchanged between each node such as terminals and servers. An example of such a network is an Internet, a LAN (Local Area Network), a Wireless LAN Area Network), WAN (Wide Area Network), PAN (Personal Area Network), and the like.

Also, since the terminal 31 or the terminal 34 shown in FIG. 1 is merely an example for convenience of explanation, the terminal of the present invention is not limited to those shown in FIG.

Referring to FIG. 1, the management server 10 may transmit content to a plurality of terminals 300 requesting content. At this time, the content means digital information or such content provided through a wired and wireless communication network. One example of such content includes characters, codes, sounds, sounds, images, and moving pictures produced in a digital manner, but is not limited to such an example.

Also, the plurality of terminals may be different models. For example, each of the plurality of terminals may be a TV device, a computer, or a portable terminal capable of connecting to a remote server through a network. Here, the TV apparatus includes, for example, a smart TV, an IPTV set-top box, and the like. The computer includes a laptop, a desktop, a laptop and the like on which a Web browser is installed, Examples of the portable terminal include a PCS (Personal Communication System), a GSM (Global System for Mobile communications), a PDC (Personal Digital Cellular), a PHS (Personal Handyphone System), a PDA Personal Digital Assistant), IMT (International Mobile Telecommunication) -2000, CDMA (Code Division Multiple Access) -2000, W-CDMA (Wideband Code Division Multiple Access), Wibro (Wireless Broadband Internet) terminal, smart phone, A personal computer, a personal computer (PC), and the like.

The management server 10 can receive the monitoring result from the plurality of cache devices 20 to 22 that monitor the content used by the plurality of terminals 300. [ Monitoring the content means that each of the plurality of cache devices 20 to 22 monitors contents requested by a plurality of terminals 300 or contents transmitted to a plurality of terminals 300. [ In this case, each of the plurality of cache devices 20 to 22 may monitor the content by the terminal type of each of the plurality of terminals 300.

The management server 10 can determine the number of concurrent users using the content or the content utilization rate for a specific time or determine whether the content is pre-distributed by assigning a weight to each type of terminal. In addition, the management server 10 may determine whether or not to pre-distribute using a specific threshold value to prevent unnecessarily large amount of contents from being pre-distributed.

In the case of a wireless network such as WCDMA (Wideband Code Division Multiple Access), all traffic is provided through a central station. Therefore, it is difficult to expect a performance improvement by using a general cache used in a wired network. On the other hand, the management server 10 can operate the cache device of the wired network and the cache device of the wireless network, respectively, and provide the interworking service between the cache device of the wired network and the cache device of the wireless network.

In particular, the management server 10 may instruct the cache device of the wireless network to use a transparent cache scheme. At this time, the transparent cache method refers to a method in which a packet recognizes a response to a content and services itself by itself even when the destination is not set as a destination. This method can provide content directly from the area without going through a central station, thereby improving the service quality of the terminal without reducing the load of the wireless network backbone.

The management server 10 can determine the cache devices 20 to 22 that require the pre-distribution of the content based on the received monitoring result. Or may request the management server 10 to pre-distribute the content at the cache devices 20-22. To this end, the management server 10 may manage the wireless cache devices 20 to 21 in the same area as the wired cache device 22 with a mutual mapping table.

At this time, local adjacency information and resource utilization information of the cache apparatus can be utilized for mapping of the cache apparatus. In general, the local adjacency of the cache device is a method of inputting local information when a user installs a cache device and registering the location in the management server, and a method of automatically locating a cache device in an adjacent region based on network topology information . If you are searching automatically, you may need a device to collect network topology information. The adjacency between cache devices can be calculated using IP (Internet Protocol) information of the cache apparatus. For example, it is possible to retrieve a list of cache devices of wireless adjacent to a wired cache device, and to provide a list of a plurality of wireless cache devices responding thereto. The resource utilization rate of the cache apparatus is information such as the CPU utilization rate, the storage utilization rate, and the network utilization rate of the cache apparatus, and can be utilized to prevent overloading in the cache apparatus.

The management server 10 can transcoding content that is distributed on demand based on the terminal information of the terminal 300 included in the monitoring results of the cache devices 20 to 22. [ Transcoding is a technology that processes, selects, and converts multimedia contents such as voice, data, and video so that they can be used in other environments. By using transcoding, a conversion function can be provided so that one content can be commonly used in different networks, resolutions, processor performances, user interfaces, etc., and the original content can be converted to suit each network bandwidth, terminal characteristics and performance , For example, content created for HDTV can be converted to be used in a mobile phone.

The management server 10 can distribute the content to the cache apparatus 20 determined to be pre-distributed. It is also possible to distribute the content to a plurality of other cache devices 21 to 22 that are geographically close to the cache device 20 whose distribution has been determined, in addition to the cache device 20 whose distribution is determined when the content is pre-distributed to the cache device 20 . This is a characteristic of a wireless network that allows a mobile station to move to an adjacent area at any time.

The cache devices 20 to 22 can recognize the movement of the terminal. At this time, the cache devices 20 to 22 can recognize the movement of the terminal by recognizing that the change of the IP used when the terminal 300 moves the network. After recognizing the movement of the terminal 300, the management server 10 can select the closest cache devices 20 to 22 in the network where the terminal 300 has moved based on the provided network topology information. At this time, the selected cache device coincides with the cache device in which the content is pre-distributed through the content monitoring. The cache devices 20 to 22 may modify the meta information file of the content to transmit new meta information including addresses of new cache devices including IP, domain, and URL to the terminal.

The management server 10 generates a signal indicating that the content has been pre-distributed to the cache apparatus 20 and transmits this signal to the other cache apparatuses 21 to 22 that are geographically adjacent to the cache apparatus 20 to which the content has been previously distributed can do. The cache devices 21 to 22 are informed that the content is pre-distributed to the cache device 20 and can receive the content from the management server 10 or the cache device 20 when the pre-distribution of the content is required. The operation of the management server 10 will be described in detail below.

2 is a configuration diagram of the management server shown in FIG. 2, the management server 10 includes a control signal transmission unit 11, a control signal generation unit 12, a cache device management unit 13, a monitoring unit 14, a content storage 15, (16). However, the management server 10 shown in FIG. 2 is only one embodiment of the present invention, and various modifications can be made based on the components shown in FIG. 2. In the conventional art, A person with knowledge can understand it.

The monitoring unit 14 receives the monitoring result data from the first cache apparatus that monitors the content used by the terminal. At this time, the first cache device is any one of a plurality of cache devices connected to the management server 10. [ Therefore, for convenience of explanation, the first cache device and the second cache device among the plurality of cache devices will be selectively used. Also, the first cache device and the second cache device may be located in different networks. For example, the first cache device may be located in a wired network, and the second cache device may be located in a wireless network.

The result data may indicate that the content monitored by the first cache device is content requiring pre-distribution. However, according to another embodiment of the present invention, the result data may indicate only the present status of the contents provided to the terminal. In this case, the first cache device transmits the provision status of the content provided to the terminal to the monitoring unit 14, and the monitoring unit 14 directly judges that the monitored content is content requiring pre-distribution based on the content provision status can do. At this time, the monitoring unit 14 periodically receives the information of the cache apparatus, and can judge that the monitored content is content requiring pre-distribution.

According to another embodiment of the present invention, a plurality of cache devices installed in the same area are configured as clusters, one of the cache devices included in the cluster is selected as a reader, It may be determined whether or not the content is distributed in advance. In addition, according to another embodiment of the present invention, the monitoring result of the cache devices included in the cluster is transmitted to the monitoring unit 14 in the cache device selected by the reader, and the monitoring unit 14 determines whether the content is pre- A way of judging is also possible.

The first cache apparatus 20 monitors contents transmitted to the terminal itself. In general, the first cache apparatus 20 may monitor a packet of content provided from the content server to the terminal via the first cache apparatus 20, or may transmit the packet to the content server from the terminal 300 It is also possible to recognize the content request signal and intercept the packet of the content to monitor the content.

The first cache device judges the content as contents requiring pre-distribution based on the degree of use of the content being monitored. In addition, it is possible to judge whether or not content pre-distribution is necessary by using the number of simultaneously used users, the content usage rate of a specific time, or an algorithm of assigning a weight to each type of terminal. And, to prevent pre-distribution of unnecessarily large amounts of content, other specific conditions may be used to determine whether pre-distribution is necessary. Also, as described above, according to another embodiment of the present invention, the first cache apparatus transmits the content provision status to the monitoring unit 14, and the content monitored by the monitoring unit 14 is a content .

The cache apparatus management unit 13 can determine a second cache apparatus cache apparatus that requires pre-distribution of the content based on the result data received by the monitoring unit 14. [

In addition, the cache apparatus management unit 13 can determine the second cache apparatus based on the location information of the plurality of cache apparatuses connected to the management server 10 via the network. The location information can be determined based on the network address information of each of the plurality of cache devices.

The cache apparatus management unit 13 can determine the second cache apparatus based on at least one of the resource utilization rate, the storage utilization rate, and the network utilization rate of the plurality of cache apparatuses connected to the management server 10 via the network in addition to the location information.

The cache apparatus management unit 13 can maintain the mapping table indicating the relationship between the cache apparatuses 20 to 22 and can determine the second cache apparatus based on the mapping table.

The cache apparatus management unit 13 detects the movement of the terminal 300 and determines the second cache apparatus based on the position information of the moved terminal. For example, the first cache device notifies the management server 10 that the terminal has moved due to the network address being used by the terminal being changed. Thus, the cache apparatus management unit 13 can select a new second cache apparatus to which the adjacent content is pre-distributed at the position of the current terminal.

It should be understood, however, that this is by way of example only and is not to be construed as limited to such embodiments.

The cache apparatus management unit 13 can transcode the contents pre-distributed to the second cache apparatus based on the result data including the terminal information of the terminal. The first cache device may also pre-distribute the transcoded content to the second cache device based on the collected terminal information.

The control signal generator 12 may generate a control signal informing the pre-distribution of the contents.

The control signal transmitting unit 11 may transmit the generated control signal to a second cache apparatus located at a different location from the first cache apparatus. For example, the control signal transmitting unit 11 can transmit a control signal for notifying the distribution of the content generated by the control signal generating unit to the cache apparatus 20 to which the content has already been distributed, and to the adjacent cache apparatus 21 have.

The notification signal transmitting unit 16 may transmit the notification signal including the metadata of the contents and the address information of the second cache apparatus to the mobile terminal. The meta information transmitted to the terminal may include access information such as IP, domain, and URL information of the new cache apparatus 21.

The content storage 15 may store contents to be provided to the terminal 300 or contents to be pre-distributed to a plurality of cache devices 20 to 22. In addition, according to various embodiments of the present invention, the content storage 15 may store data necessary for the calculation process described in the description of the present invention or generated during the calculation process. Examples of such content storage 15 include a hard disk drive, a ROM (Read Only Memory), a RAM (Random Access Memory), a flash memory and a memory card.

 3 is a diagram illustrating a process in which data is transmitted and received between each member included in the content pre-distribution system of FIG. 1 according to an embodiment of the present invention. 3, a description will be made of an example of a process of transmitting and receiving a signal according to an exemplary embodiment of the present invention. However, the present invention is not limited thereto. It should be apparent to those skilled in the art that the process of transmitting and receiving data may be changed. Referring to FIG. 3, the first cache apparatus 20 receives a content request signal of the terminal 300 (S301). The content server receives the content distribution request from the first cache apparatus 20 (S302) and distributes the content to the first cache apparatus 20 (S303). The first cache apparatus 20 provides the content to the terminal 300 (S304), and monitors the content provided to the terminal 300 (S305). The first cache device requests pre-distribution of the content to the management server 10 based on the monitoring result (S306), and the management server 10 selects a cache device to pre-distribute the content (S307) And distributes the content to the second cache apparatus to be pre-distributed (S308). The first cache apparatus 20 transmits to the terminal a signal indicating that the content is pre-distributed to the second cache apparatus (S310), and the terminal 300 transmits the second The content is requested by the cache apparatus 21 (S311). Thereafter, the terminal 300 receives the content from the second cache apparatus 21 (S312).

FIG. 4 is a configuration diagram of one of the plurality of cache devices shown in FIG. 1 according to an embodiment of the present invention. 4, the cache apparatus 20 includes a monitoring unit 201, a content providing unit 202, a data transmitting unit 203, a control signal receiving unit 204, and a content processing unit 205. At this time, characters, codes, sounds, sounds, images, and moving pictures are included in an example of the contents as described above.

The monitoring unit 201 may collect the type of the terminal and the setting information of any one of the plurality of terminals 300 and monitor the content for each terminal type.

The result data transmitting unit 203 can transmit the monitored result from the monitoring unit 201 to the management server 10.

The control signal receiving unit 204 receives a signal informing that the content has been pre-distributed to the cache apparatus 20 from the content server or a signal indicating the pre-distribution of the content monitored by the external cache apparatus existing at a different position from the cache apparatus 20 Lt; / RTI >

The content processing unit 205 may store the content provided from the content server.

The content providing unit 202 may receive the content request signals of the plurality of terminals 300 and may provide the content stored in the content processing unit 205 to the requesting terminal 31. [ It is to be understood that the present invention is not limited thereto.

Such a cache apparatus 20 performs the operations described with respect to the cache apparatus described above with reference to Figs. 1 to 3 above. Therefore, what has not been described with respect to the cache apparatus in FIG. 4 applies the contents described for the cache apparatus through FIGS. 1 to 3 in advance. In other words, a more detailed description of the cache apparatus 20 of FIG. 4 will be omitted because it can be easily deduced by those skilled in the art from the same or similar contents as those described above with reference to FIGS. 1 to 4 above.

5 is a service flow diagram according to an embodiment of the present invention. (S501). If a pre-distribution of the content is required (S502), a cache device to be pre-distributed is selected in consideration of local information, network conditions, cache device resources, etc. (S503 )do. If necessary, the content is transcoded and distributed in a form corresponding to the terminal information of the terminal based on the terminal information of the terminal (S504 and S505). If not necessary, the content is distributed without transcoding (S506). Upon completion of the pre-distribution of the content, the connection information of the cache apparatus that can receive the content to the terminal 300 is transmitted (S507), and the terminal 300 receives the content from the cache apparatus based on the received connection information S508), and the content is used (S509).

6 is a flowchart illustrating a content pre-distribution method according to an embodiment of the present invention. The content pre-distribution method according to the embodiment shown in Fig. 6 includes steps that are processed in a time-series manner in the management server 10 shown in Fig. Therefore, the contents described above with respect to the management server 10 shown in FIG. 2 are also applied to the content pre-distribution method according to the embodiment shown in FIG.

In step S601, the monitoring unit 14 receives the monitoring result of the content used by the terminal 300 from the cache apparatus 20 among the plurality of cache apparatuses. In step S602, the cache apparatus management unit 13 determines the cache apparatus 20 that requires pre-distribution of the content among a plurality of cache apparatuses based on the monitoring result of the monitoring unit 14. [ In step S603, the control signal generation unit 12 generates a control signal informing the pre-distribution of the contents. In step S604, the control signal transmitting unit 11 transmits the generated signal to the cache apparatus 21 existing at a different position from the cache apparatus 20 among the plurality of cache apparatuses.

The content pre-distribution method according to the embodiment described with reference to FIG. 6 may be implemented 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. The computer readable medium may also 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 any computer-readable instructions, data structures, program modules, or other data of a modulated data signal, such as a carrier wave, or other transport mechanism, and includes any information delivery media.

It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims . It is therefore to be understood that the above-described embodiments are illustrative and non-restrictive in every respect. For example, the components described in the singular may also be implemented in a combined form.

The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. .

10: Management Server
13:
14: Monitoring section
20: cache device
300: terminal

Claims (18)

A management server for transmitting control signals to a plurality of cache devices,
A monitoring unit that receives result data of the monitoring from a first cache apparatus that monitors contents used by the terminal;
A cache device manager configured to determine a second cache device cache device requiring pre-distribution of the content based on the received result data;
A control signal generation unit for generating a control signal informing the pre-distribution of the content; And
And a control signal transmitter configured to transmit the generated control signal to the second cache apparatus located at a location different from the first cache apparatus.
The method of claim 1,
Wherein the content is transmitted from the management server to the terminal, and the first cache device monitors the transferred content.
The method of claim 2,
Wherein the first cache device recognizes a content request signal transmitted from the terminal to the management server, and intercepts the packet of the content to monitor the content.
The method of claim 1,
Wherein the result data indicates that the monitored content is content requiring pre-distribution.
The method of claim 4, wherein
Wherein the first cache device determines the content as content requiring pre-distribution based on the degree to which the monitoring content is used.
The method of claim 5, wherein
Wherein the first cache apparatus judges that the content is content requiring pre-distribution by applying different weights to the terminals of the terminal.
The method of claim 1,
Wherein the cache apparatus management unit determines the second cache apparatus based on position information of a plurality of cache apparatuses connected to the management server via a network.
The method of claim 7, wherein
Wherein the cache apparatus management unit determines the location information based on network address information of each of the plurality of cache apparatuses.
The method of claim 1,
Wherein the cache apparatus management unit determines the second cache apparatus based on at least one of a resource usage rate, a storage usage rate, and a network usage rate of a plurality of cache devices connected to the management server via a network.
The method of claim 1,
Wherein the cache apparatus management unit holds a mapping table indicating a relationship between a plurality of cache apparatuses connected to the management server via a network and determines the second cache apparatus based on the mapping table.
The method of claim 1,
Wherein the first cache device comprises:
Collects terminal information of the terminal,
Wherein the terminal information is included in the result data,
Wherein the cache apparatus management unit transcodes contents pre-distributed to the second cache apparatus based on the terminal information.
The method of claim 1,
Wherein the first cache device comprises:
Collects terminal information of the terminal,
Wherein the terminal information is included in the result data,
Wherein the first cache device transcodes content pre-distributed to the second cache device based on the terminal information.
The method of claim 1,
Wherein the first cache device is located in a wired network and the second cache device is located in a wireless network.
The method of claim 1,
Wherein the cache apparatus management unit detects movement of the terminal and determines the second cache apparatus based on the location information of the moved terminal.
The method of claim 1,
And a notification signal transmitter for transmitting a notification signal including the metadata of the contents and the address information of the second cache apparatus to the terminal.
A method for transmitting a control signal to one of a plurality of cache devices by a management server,
Receiving monitoring result data of a content used by the terminal from the first cache device among the plurality of cache devices;
Determining a second cache device that requires pre-distribution of the content among the plurality of cache devices based on the received result data;
Generating a control signal indicating the pre-distribution of the content; And
And transmitting the generated control signal to the second cache device.
A cache apparatus for acquiring a content corresponding to a control signal received from a management server,
A content monitoring unit for monitoring a content used by at least one terminal connected through a network;
A result data transmitter configured to generate result data of the monitoring and transmit the generated result data to the management device;
A control signal receiver configured to receive a control signal from the management device to notify a pre-distribution of external content monitored by an external cache device located at a location different from the cache device; And
And a content processor configured to acquire the external content and store the external content.
The method of claim 17,
Further comprising a content providing unit for receiving a content request signal for requesting an external content from any one of the at least one terminal and providing external content previously stored in the terminal.

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