KR101076473B1 - Apparatus and method for managing multimedia data based on time constraint multiple access technique - Google Patents

Abstract

A device for managing multimedia data implemented in a plurality of clients requesting multimedia data and a central server providing the requested multimedia data and a proxy server connected to a wired / wireless network, the apparatus comprising: a session manager configured to manage data request sessions with a plurality of clients; ; A main memory manager for loading multimedia data requested from a first client of the plurality of clients into a main memory of the proxy server; And a data storage management unit configured to store the requested multimedia data in a storage device when a session with a second client of the plurality of clients is established and the multimedia data loaded in the main memory is requested. The management apparatus is disclosed.

Description

Apparatus and method for managing multimedia data based on time constraint multiple access technique

The present invention relates to multimedia data management, and more particularly, to a management apparatus, a management method, and a recording medium for efficiently managing multimedia data in a storage device of a proxy server.

Due to the rapid development of communication technology, real-time video service through the network is becoming common. The most important thing about the use of video data on the Internet today is to be able to guarantee its quality. Current video transmissions are very sensitive to losses and delays, and have been pointed out as a major problem in the development of various fields based on them.

To solve this problem, the quality of internet video-on-demand (VOD) services can be greatly improved by utilizing video proxy servers located near users.

Locally located video proxy servers and users can deliver large amounts of video data requested by users directly to multiple users without having to go through a complex Internet path. (initial latency) solve the problem.

However, the video proxy server has a disadvantage in that it has a relatively limited capacity compared with the storage space of the main server or the central video server. Therefore, there is a need for a method of storing only video data that will be continuously requested by the user in the future.

In this study, the prefix storage that stores only the prefix, which is the beginning of the video requested by the user, in the video proxy server, taking advantage of the fact that the user has an access pattern that requests the beginning of the video and has a relatively short duration. A prefix caching technique has been proposed.

When a user requests a video, the prefix storage method sends the prefix, which is the first part of the video stored in the video proxy server, to the user to minimize initial delay, and at the same time, the latter part of the suffix (from the remote central server) suffix) is a technique to receive.

In a recent study based on such a prefix storage scheme, a PPC (Popularity-based Prefix Caching) method using a popularity determined according to the total size of data requested by users has been proposed.

The proposed PPC method determines the size of video data to be stored in the video proxy server according to the popularity and stores the first video data of the corresponding size first.

However, since this method does not consider access recentness, the video data that is newly requested may not be stored in the video proxy server because of the videos that have been frequently requested in the past.

In another study, an LRU-k algorithm using a predetermined number of user request time information and a Greedy-Dual algorithm which decides to store and delete a video in a video proxy server in consideration of the user's request priority are proposed.

However, these methods do not fully consider the information related to the user request of the video data. In particular, since all video data requested by the user are stored in the video proxy server, video data that cannot be requested after being stored once is also stored in the video proxy server. This immediately causes excessive deletion of video data when there is insufficient space for storing new video data.

An object of the present invention is to propose a management scheme for selecting and storing only video data that users continuously request in a video proxy server having a relatively limited storage space as compared to a central server located remotely.

In order to achieve the above object, an embodiment of the present invention provides a device for managing multimedia data implemented in a plurality of clients requesting multimedia data and a central server providing the requested multimedia data and a proxy server connected to a wired or wireless network. A session manager configured to manage a data request session with the plurality of clients; A main memory manager for loading multimedia data requested from a first client of the plurality of clients into a main memory of the proxy server; And a data storage management unit configured to store the requested multimedia data in a storage device when a session with a second client of the plurality of clients is established and the multimedia data loaded in the main memory device is requested. A multimedia data management apparatus is provided.

In order to achieve the above object, an embodiment of the present invention provides a method for managing multimedia data operating in a proxy server connected to a wired or wireless network with a plurality of clients requesting multimedia data and a central server providing the requested multimedia data. Managing a data request session with the plurality of clients; Loading multimedia data requested from a first client of the plurality of clients into a main memory of the proxy server; And storing the requested multimedia data in a storage device when a session with a second client of the plurality of clients is established and the multimedia data loaded in the main memory is requested. Provide a data management method.

In order to achieve the above object, an embodiment of the present invention is to execute a method for managing multimedia data operating in a proxy server connected to a wired or wireless network with a plurality of clients requesting multimedia data and a central server providing the requested multimedia data. A recording medium having recorded thereon a program, comprising: a function of managing a data request session with the plurality of clients; Loading multimedia data requested from a first client of the plurality of clients into a main memory of the proxy server; And a program for implementing a function of storing the requested multimedia data in a storage device when a session with a second client of the plurality of clients is established and the multimedia data loaded in the main memory is requested. It provides a recording medium that can be read by.

In order to achieve the above object, an embodiment of the present invention provides a device for managing multimedia data implemented in a plurality of clients requesting multimedia data and a central server providing the requested multimedia data and a proxy server connected to a wired or wireless network. A main memory manager for temporarily loading multimedia data corresponding to a first request from the plurality of clients into the main memory; and indicating whether a second request for the multimedia data loaded into the main memory is received from the plurality of clients. And a data storage management unit for storing the multimedia data stored in the main memory in the storage of the proxy server according to access recentness, wherein the storage size of the storage of the proxy server is stored in the central server. Provides a multimedia data management unit to a relatively is smaller than the value.

According to the present invention, only data to be continuously requested by the user among the video data requested by the user are selected and moved to the storage space of the video proxy server. Therefore, users frequently request videos stored in the video proxy server, and the video proxy server can transmit the video data to the user quickly, so that excessive network traffic caused by data transmission from a remote central server The problem of low transmission quality due to service delay can be solved.

FIG. 1 is a data structure illustrating a pyramidal media partitioning scheme in which a central server divides and transmits multimedia data (eg, video data) into units of a plurality of segments.
2 is a diagram illustrating a VOD system structure in which an apparatus for managing multimedia data according to an embodiment of the present invention operates.
3 is a diagram illustrating a process of temporarily storing and deleting a multimedia data management apparatus according to an embodiment of the present invention when operating in a single session.
4 and 5 are views illustrating a process of temporarily storing, storing and deleting when the multimedia data management apparatus operates in a multi-session according to an embodiment of the present invention.
6 is a diagram illustrating a waiting time for maintaining a session for storing segments in a multimedia data management apparatus according to an embodiment of the present invention.
7 is a functional block diagram illustrating components of a multimedia data management apparatus according to an embodiment of the present invention.
8 is a flowchart illustrating a process of storing multimedia data using a virtual connection technique in a multimedia data management apparatus according to an embodiment of the present invention.
9 is a flowchart illustrating a process of deleting stored multimedia data in order to secure a free space of a storage device of a relatively narrow proxy server in a multimedia data management apparatus 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 the components of each drawing, it should be noted that the same reference numerals are used to refer to the same components as much as possible even if displayed on different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In addition, in describing the component of this invention, terms, such as 1st, 2nd, A, B, (a), (b), can be used. These terms are only for distinguishing the components from other components, and the nature, order or order of the components are not limited by the terms. If a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected to or connected to that other component, but there may be another configuration between each component. It is to be understood that the elements may be "connected", "coupled" or "connected".

In the present invention, if the multimedia data (eg, video data) requested by the user is loaded once into the main memory of the proxy server, the multimedia data is continuously requested in the set time. We propose a time-constrained multiple request scheme for storing data in storage.

The present invention relates to an apparatus and method for managing multimedia data such as video / audio / text data or their combined data, but for convenience of description, the following description will be given using "video data" of multimedia data as an example ( For example, a central video server, video proxy server, video data, etc.).

FIG. 1 is a data structure illustrating a pyramid media segmentation technique in which video data is divided and transmitted in units of a plurality of segments in a central server.

For the method proposed by the present invention, as shown in FIG. 1, a pyramid media segmentation technique is used in which video data is divided and transmitted by a central unit. Here, pyramid division divides one video into several segments such as seg.1 (110) to seg.4 (140), and the number of blocks included in the segment is increased as the number of segments (k) increases from 1 to 4. Increase to 2 ^{k- 1} (1,2,4,8, .., etc.). The media segmentation technique can quickly delete or store a lot of data at a low cost, which effectively reduces initial delay and network traffic.

2 is a diagram illustrating a VOD system structure in which an apparatus for managing multimedia data according to an embodiment of the present invention operates.

As shown in FIG. 2, the video proxy server 220 may be located in the local area network 240 between the user 210 and may be used to solve the problem of reducing the load of the central server 230, initial transmission delay, and video packet loss. have.

The central server 230 or proxy server 220 of FIG. 2 has the same configuration as a conventional web server or web server. However, the software includes a program module implemented in any language such as C, C ++, Java, Visual Basic, Visual C and performing various functions.

The above-mentioned server is generally connected to an unspecified number of clients and / or other servers through an open computer network such as the Internet, and is a computer that receives a task execution request from a client or another web server and derives and provides a work result thereof. It refers to a system and computer software (server program) installed therefor. In addition to the above-described server program, it should be understood as a broad concept including a series of application programs (Application Program) running on the server and, in some cases, various databases (DB) built therein.

The server described above may be implemented by using server programs that are variously provided according to operating systems such as DOS, Windows, Linux, UNIX, Macintosh, and the like for general server hardware. For example, the websites used in the Windows environment, the Internet Information Server (IIS), and the CERN, NCSA, and APPACH used in the Unix environment may be used.

On the other hand, the user terminal (client, 210) is generally a personal PC, but any terminal is possible if the server and server-client communication is possible by connecting to the wired and wireless network (240, 250), smart phones, notebook computers It is a broad concept that includes all communication computing devices such as mobile communication terminals and PDAs.

The networks 240 and 250 may be closed networks such as a local area network (LAN) and a wide area network (WAN) as a network connecting servers and terminals, but may also be open types such as the Internet. . The Internet has many services in the TCP / IP protocol and its upper layers: HyperText Transfer Protocol (HTTP), Telnet, File Transfer Protocol (FTP), Domain Name System (DNS), Simple Mail Transfer Protocol (SMTP), and SNMP ( The global open computer network architecture that provides the Simple Network Management Protocol (NFS), Network File Service (NFS), and Network Information Service (NIS). In addition, when the user terminal 210 is a mobile communication terminal or a smart phone, the networks 240 and 250 may include a mobile communication network.

Meanwhile, in FIG. 2, since the storage space of the video proxy server 220 has a storage space relatively smaller than that of the remote central server 230, the video proxy server 220 will be frequently requested by the user 210. Only the determined video needs to be sorted and stored in the storage device and transmitted to the user 210. However, as the video request pattern of the user changes over time, it is determined that the request will be made continuously. Therefore, the video stored in the video proxy server is no longer requested by the user, which causes the necessity of deleting the video. Efficient storage space management is required.

To this end, the present invention proposes a method for securing a free space by efficiently storing a new video in a storage device of a video proxy server and selecting and removing existing stored video. For efficient storage and transmission of video, this proposal utilizes a media segmentation technique that consists of one video into several segments. Segmentation of the segment considers an exponentially increasing method (2 ^k-1 ). In addition, a prefix storing technique is used to store a prefix, which is the first half of the video, in a storage device when a user requests a video.

The time-constrained multiple request scheme proposed by the present invention is a method of selectively storing only segments of video predicted to be frequently requested by a user in a storage device.

To this end, the video proxy server maintains segments of the video requested by the user in the main memory until the user request is interrupted, and stores them in the storage when the user requests the segment later.

3 is a diagram illustrating a process of temporarily storing and deleting a multimedia data management apparatus according to an embodiment of the present invention when operating in a single session.

As shown in FIG. 3A, the user establishes a session for the video of interest and requests segments (request 1). The video proxy server maintains the segment requested by the user in the main memory (temporary storing) 320 and stores the segment corresponding to the prefix 310 of a predetermined size in the storage.

Use Equation 1 below to select a cut-off point (CP) segment to determine the size of the prefix. Segments before the selected segment are prefixed and subsequent segments are suffixed.

Here, CPi is a bullet point of any video i and c is the total number of users who requested the video. AT (i, j) is also the video i is the request duration by user j and Popi is the total number of requests for video i.

If a new session for the video is not established before the first request session (request 1) is interrupted as shown in FIG. 3 (b), all segments 330 loaded in the main memory are deleted (erased).

4 and 5 are views illustrating a process of temporarily storing, storing and deleting when the multimedia data management apparatus operates in a multi-session according to an embodiment of the present invention.

Referring to FIG. 4 (a), if a new session is established (request 2) and a segment 420 is temporarily requested to be loaded into the main memory, the video proxy server as shown in FIG. Store in the storage device (430). However, if not requested by the user, the corresponding segment is deleted as shown in FIG. 4 (c) (440).

Referring to FIG. 5 (a), when all video segments temporarily loaded in the main memory are requested by the connected session, the video proxy server stores the segments in the storage device (520) and FIG. 5 (b). When the session (request 2) of the second request ends without another session setup, the segments that were temporarily stored are deleted (540). Meanwhile, referring to FIG. 5C, the requested segment in the second session (request 2) is temporarily loaded into the main memory and waits for the user's request (request 3) (550).

6 is a diagram illustrating a waiting time for maintaining a session for storing segments in a multimedia data management apparatus according to an embodiment of the present invention.

In the time-constrained multi-request scheme proposed above, a segment of a video can be stored only when a new session is established before the first request session is interrupted. (Ie, see 610 of FIG. 6 (a)).

If a user's request for any video is reduced and a new session is not established before the first request session is aborted then that video will not be stored in any segment. Therefore, another proposal of the present invention proposes a virtual bridge scheme for maintaining a suspended session for a time interval calculated in consideration of a user's request pattern.

In order to maintain a suspended session for a certain time in a virtual connection in an embodiment of the present invention, the waiting time Ti (k) is measured using the following Equation 2 for the segment requested by the user. do. (I.e. see 620 of FIG. 6 (b))

If the user requested a segment stored in the main memory during the previous waiting time, the segment will be moved to the storage of the video proxy server, but if not requested during the previous waiting time, the segment will be deleted from the main memory.

Pi (k) is a request probability of segment k of any video i, which is the number of times segment k of any video i is requested divided by the number of times all segments of the video are requested. N is also the number of videos present in the main memory and α i (1) is the interval between the most recently requested time of the first segment of any video i and the time requested before that time.

7 is a functional block diagram showing the components of the multimedia data management apparatus 700 according to an embodiment of the present invention.

Referring to FIG. 7, the multimedia data management apparatus 700 may include a session manager 710 managing a data request session with a client 760, and a main memory for loading video data requested from the client 760 into a main memory of a proxy server. The device manager 720 includes a data storage manager 730 for storing the requested video data in the storage device 770 when a session with the client 760 is established and the video data loaded in the main memory is requested. do.

Meanwhile, the main memory manager 720 may further include a virtual connector 721 that virtually maintains an existing session for a predetermined time based on the request pattern of the client even after the session of the client 760 is stopped.

In addition, the multimedia data management apparatus 700 may further include a file transmitter 750 for transmitting the video data requested from the client 760 to the client 760, and the storage space of the storage device 770 of the proxy server. It may further include a data deletion management unit 740 for deleting the stored video data when less than this predetermined threshold.

Here, the main factor causing the I / O latency of the video proxy server is the search overhead used to search for the video stored in the storage 770. In particular, a video proxy server with limited storage space performs continuous file deletion due to the storage of new video, and excessive browsing overhead in this case negatively affects the efficiency of the storage space. In this case, there are two problems with the main memory having limited storage space.

The first is that it can be difficult to find contiguous space for storing video data with large segment numbers, and the second can cause external fragmentation problems, which can greatly affect the performance of managing the video proxy server using main memory. Is that there is.

In order to solve this problem, the present invention also proposes a storage scheme for allocating storage space by segment in order to solve excessive search overhead and fragmentation that may occur due to continuous deletion and storage of video segments in a main memory having limited storage space. do.

The proposed storage scheme has the physical address information where each video is stored based on the segment number, and it is possible to directly access the stored video using the linked list. That is, a file directory is composed of a set of videos, and each video is linked to an index table having segment storage information of the corresponding video using a linked list.

The index table plays a key role in mapping the physical video segments stored in storage from logical data structures. Therefore, the indexes of the index table have the physical address information of the storage device in which each segment of the video is stored and can directly access the stored segments by using a linked list. By doing so, the video proxy server can quickly save new video to the storage device or search for stored video, and solve the fragmentation problem that occurs when deleting.

 In addition, in the present invention, in order to efficiently store the segments of the video requested by the user in the main memory, the main memory size (MMS) is divided into storage spaces according to segment numbers. The number of blocks (NOB) of the partition space in the main memory of any segment is calculated by Equation 3 below.

Here, s (k) is the size of the segment k, p (k) is the average of the probability that the segment k is requested for all the videos present in the main memory, these probabilities are calculated by a previously performed experiment do. In addition, j is the number of segments constituting one video, and m (k) is the number of blocks included in segment k.

8 is a flowchart illustrating a process of storing multimedia data using a virtual connection technique in a multimedia data management apparatus according to an embodiment of the present invention.

Referring to FIG. 8, in the process of storing multimedia data using a virtual connection scheme, first, when a k-th segment (ik) of an arbitrary video i is requested (810), the requested segment (ix) is a storage device of a proxy server. In operation 815, the storage device transmits the stored segment ix to the user if the storage device 820 exists.

However, if the segment ix requested for the storage device does not exist in the storage device, it is next determined whether it exists in the main memory which is the main memory (825). If there is a segment ix in the main memory, it is transmitted to the user (830), and the segment ix, which has been loaded in the main memory, is moved from the main memory to the storage (835).

If the requested segment (ix) is not in storage or in main memory, the video proxy server requests the main server to transmit segment ix (840), and sends the received segment (ix) to the proxy server's main memory. After loading, the data is transmitted to the user (845).

Even if the first request session is interrupted, after waiting for another user to request segment (ix) for a certain waiting time Ti (k) (850), if no other request is made, delete segment (ix) from main memory ( 865) If another request occurs within the waiting time, the requested segment ix is sent to the user (855) and the requested segment ix is moved from the main memory to the proxy server's storage (860).

9 is a flowchart illustrating a process of deleting stored multimedia data in order to secure a free space of a storage device of a relatively narrow proxy server in a multimedia data management apparatus according to an embodiment of the present invention.

The video proxy server has a relatively small storage space compared to the remote central server. Therefore, there is a need to select and remove the least likely segment among the video segments stored in the storage device to secure the storage space of the newly requested video. To this end, the present invention proposes a deletion algorithm considering the request time.

Referring to FIG. 9, the deletion algorithm is performed when the storage space of the video proxy server is smaller than the set threshold (910). This is because it is inefficient to secure the space when the video proxy server storage device runs out of space due to the input of a new video segment. The threshold is the size of the largest segment stored in the storage device.

First of all, the video stored in the storage device is divided into prefix and suffix. If any video has not been requested for a predetermined time μi, all segments of the video are set as suffixes (920). The time μi set here is calculated by Equation 4 below.

Where n is the number of videos present in the storage and αi (1) is the interval between the most recently requested time of the first segment of any video i and the time requested before that time.

The stored videos are sorted by the previously requested chronological order (930), and if a suffix is present (940), then deleted (950) in order from the last segment of the suffix of the oldest requested video. If the suffix no longer exists in the storage of the video proxy server (940), delete it in order from the last segment of the oldest requested video prefix until the free space on the storage is greater than the threshold (970). Perform 960.

The present invention includes a recording medium having recorded thereon a program for executing the above method for managing multimedia data operating in a proxy server.

Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disks, optical data storage devices, and the like. Also, carrier waves (eg, transmission through a network 130 such as the Internet) It also includes the implementation in the form of). The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

In addition, functional programs, codes, and code segments for implementing the present invention can be easily inferred by programmers in the art to which the present invention belongs.

In the above description, all elements constituting the embodiments of the present invention are described as being combined or operating in combination, but the present invention is not necessarily limited to the embodiments. In other words, within the scope of the present invention, all of the components may be selectively operated in combination with one or more. In addition, although all of the components may be implemented in one independent hardware, each or all of the components may be selectively combined to perform some or all functions combined in one or a plurality of hardware. It may be implemented as a computer program having a. Codes and code segments constituting the computer program may be easily inferred by those skilled in the art. Such a computer program may be stored in a computer readable storage medium and read and executed by a computer, thereby implementing embodiments of the present invention. The storage medium of the computer program may include a magnetic recording medium, an optical recording medium, a carrier wave medium, and the like.

In addition, the terms "comprise", "comprise" or "having" described above mean that the corresponding component may be included, unless otherwise stated, and thus excludes other components. It should be construed that it may further include other components instead. All terms, including technical and scientific terms, have the same meanings as commonly understood by one of ordinary skill in the art unless otherwise defined. Terms commonly used, such as terms defined in a dictionary, should be interpreted to coincide with the contextual meaning of the related art, and shall not be construed in an ideal or excessively formal sense unless explicitly defined in the present invention.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

Claims (18)

An apparatus for managing multimedia data implemented in a plurality of clients requesting multimedia data and a proxy server connected to a wired / wireless network with a central server providing the requested multimedia data.
A session manager configured to manage data request sessions with the plurality of clients;
A main memory manager for loading multimedia data requested from a first client of the plurality of clients into a main memory of the proxy server; And
A data storage management unit configured to store the requested multimedia data in a storage device when a session with a second client of the plurality of clients is established and the multimedia data loaded in the main memory is requested;
The multimedia data is divided and processed into a plurality of segments, and the plurality of segments are composed of a prefix and a suffix.
The main memory management unit,
Dividing the total main memory space into storage spaces according to the segment number,
s (k) is the size of the segment k, p (k) is the average value of the probability value of the segment k for all the multimedia data present in the main memory, j is a segment constituting one multimedia data Where MMS is the size of the total main memory space,

And the number NOB (k) of blocks in the storage space according to segment k is determined by the above equation.
The method of claim 1,
The main memory management unit,
And erasing the multimedia data stored in the main memory when the session of the first client is interrupted before the session of the second client is established for the requested multimedia data.
delete The method of claim 1,
The data storage management unit,
Storing a segment corresponding to the prefix in the storage device;
CPi is the bullet point of any of the multimedia data i, c is the total number of users who requested the video, AT (i, j) is the multimedia data i is the request duration by user j, and Popi is the multimedia When data i is the total number requested,

And the segment of the prefix is at least one segment before a break point determined by the equation.
The method of claim 1,
The main memory management unit,
And a segment newly requested by the second client in addition to the segment of the multimedia data loaded in the main memory, to the main memory.
The method of claim 1,
The main memory management unit,
And a virtual connection unit for maintaining the session for a predetermined time even after the session of the first client is interrupted based on a request pattern of the client.
The method of claim 6,
The virtual connection unit,
Pi (k) is a request probability of dividing the number of times the segment k of the multimedia data i is requested by the number of times all segments of the multimedia data are requested, n is the number of multimedia data present in the main memory, α i (1) is the first segment of the multimedia data i is the interval between the most recently requested time and the time requested before that time,

The predetermined time Ti (k) to maintain the session is determined by the equation.
delete The method of claim 1,
The data storage management unit,
And an index table that maps the physical address information of the storage device of the proxy server, in which the segment of the multimedia data is stored, with a logical data structure, and directly accesses the stored segment using a linked list. Multimedia data management device.
The method of claim 1,
Further comprising a file transmitter for transmitting the multimedia data requested from the plurality of clients to the client,
When the requested multimedia data exists in the storage of the proxy server, the file transmitter transmits the stored multimedia data to the client,
When the requested multimedia data exists in the main memory, the file transmitter transmits the multimedia data to the client, and the data storage manager stores the multimedia data in the main memory in the storage of the proxy server. and,
When the requested multimedia data is received from the central server, the file transmitter transmits the received multimedia data to the client, and the main memory manager loads the received multimedia data into the main memory of the proxy server. Multimedia data management device.
The method of claim 1,
And a data deletion management unit for deleting the stored multimedia data when the storage space of the storage device of the proxy server is smaller than a predetermined threshold value.
And said threshold is the size of the largest segment of said stored multimedia data.
The method of claim 11,
The data deletion management unit,
In the case of multimedia data that has not been requested for a predetermined time of the stored multimedia data, all segments of the multimedia are set as suffixes.
n is the number of multimedia data present in the storage of the proxy server, and αi (1) is the interval between the most recently requested time of the first segment of any multimedia data i and the time requested before that time. time,

And said set time [mu] i is determined by the equation.
The method of claim 12,
The data deletion management unit,
And sort the multimedia data present in the storage of the proxy server in a previously requested time order.
The method of claim 13,
The data deletion management unit,
And deleting the last segment from one or more segments corresponding to the suffix of the longest requested multimedia data among the multimedia data arranged in the storage device of the proxy server.
The method of claim 14,
The data deletion management unit,
If there is no segment corresponding to the suffix among the multimedia data arranged in the storage of the proxy server,
And deleting the last segment from one or more segments corresponding to the prefix of the multimedia data requested the longest.
A method of managing multimedia data operating in a proxy server connected to a wired / wireless network with a plurality of clients requesting multimedia data and a central server providing the requested multimedia data,
Managing a data request session with the plurality of clients;
Loading multimedia data requested from a first client of the plurality of clients into a main memory of the proxy server; And
Storing the requested multimedia data in a storage device when a session with a second client of the plurality of clients is established and there is a request for the multimedia data loaded on the main memory device;
The multimedia data is divided and processed into a plurality of segments, and the plurality of segments are composed of a prefix and a suffix.
Loading the main memory device,
Dividing the total main memory space into storage spaces according to the segment number,
s (k) is the size of the segment k, p (k) is the average value of the probability value of the segment k for all the multimedia data present in the main memory, j is a segment constituting one multimedia data Where MMS is the size of the total main memory space,

The number NOB (k) of blocks in the storage space according to segment k is determined by the above equation.
delete delete

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