JP2010102651A - Content distribution storage system, open period controller, open period control method and control processing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a content distribution storage system, an open period controller, an open period control method and a control processing program, efficiently controlling the open period during which content is available, and efficiently managing the content. <P>SOLUTION: In the content distribution storage system, the open period controller controlling the open period during which the content is available for each content calculates an open end date based on transition of the number of pieces of replicated data according to the elapse of time from an open start date, and sets new calculated open end date in place of an already set open end date. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technical field of a peer-to-peer (P2P) type communication system including a plurality of node devices that can communicate with each other via a network.

  In this type of peer-to-peer communication system, copy data (hereinafter referred to as “replica”) of a plurality of content data (content data such as movies and music) is distributed and stored (arranged) in a plurality of node devices. A distributed content storage system that makes it possible to use replicas between node devices is known, and this improves fault tolerance and access dispersibility. The location of the replicas thus distributed and stored can be efficiently searched using a distributed hash table (hereinafter referred to as DHT (Distributed Hash Table)) as disclosed in, for example, Patent Document 1.

For a content that is input for the first time to such a distributed content storage system, a public period (a period from the start of use to the end of use) in which the content can be used at the time of input is set.
JP 2006-197400 A

  However, in the conventional distributed content storage system, although there is a demand for viewing and the like, the content becomes unavailable due to the expiration of the publication (end of the publication period) or until the publication deadline even though there is no usage demand It is difficult to perform efficient content management because it is not disabled (cannot be deleted), leading to wasted storage capacity of a server device or the like storing a replica of the content.

  The present invention has been made in view of the above points, and the like. The content distributed storage system, which enables efficient control of a publication period during which content can be used, and enables efficient content management, and publication It is an object to provide a period control device, a disclosure period control method, and a control processing program.

  In order to solve the above-described problem, the invention according to claim 1 is a distributed content storage system including a plurality of node devices that can communicate with each other via a network. The contents can be stored in a distributed manner, the contents can be used among the respective node devices, and the publication period in which the contents can be used in the contents distributed storage system in which the number of the replicated data varies with the passage of time is set for each content. A public period control device for controlling the public period, a public period setting means for setting a public start date and time and a public end date and time for determining the public period, and the number of the duplicate data based on information collected from a plurality of the node devices The number of replicated data to calculate the number of replicated data according to the passage of time from the start date and time of publication A publication end date and time calculating means for calculating the publication end date and time, and the publication period setting means resets the calculated publication end date and time instead of the already set publication end date and time. It is characterized by that.

  According to this invention, a new publication end date is calculated based on the transition of the number of replicated data according to the passage of time from the set publication start date, and the calculation is performed in place of the already set publication end date. Since it is configured to reset the published end date and time, it is possible to efficiently control and manage the publication period reflecting the change in the content usage demand.

  According to a second aspect of the present invention, in the disclosure period control device according to the first aspect, a display control means for displaying a difference between the public end date and time that has already been set and the calculated public end date and time, Receiving means for accepting a reset instruction from a user, wherein the disclosure period setting means resets the publication end date and time when the reset instruction is received.

  According to this invention, the administrator can extend or shorten the publication end date and time if necessary after confirming and judging the displayed information, and efficient content management becomes possible.

  According to a third aspect of the present invention, in the public period control device according to the first or second aspect, a public end date / time information notification for notifying the plurality of node devices of information indicating the reset public end date / time. The apparatus further comprises means.

  According to the present invention, each node device can be promptly updated with the disclosure end date and time of the corresponding content.

  An invention of a control processing program according to a fourth aspect is characterized in that a computer is caused to function as the disclosure period control device according to any one of the first to third aspects.

  The invention according to claim 5 is a content distributed storage system comprising a plurality of node devices that can communicate with each other via a network, wherein the replicated data of the plurality of contents is distributed and stored in the plurality of node devices, In a distributed content storage system in which the content can be used between the node devices and the number of the replicated data varies with the passage of time, a disclosure period control device that controls the disclosure period in which the content can be used for each content A publication period setting means for setting a publication start date and time and a publication end date and time for determining the publication period; a duplicate data number calculation means for calculating the number of duplicate data based on information collected from a plurality of the node devices; , Calculating the publication end date and time based on the transition of the number of replicated data according to the passage of time from the publication start date and time That a public end date calculation means, wherein the publication period setting means is characterized by resetting the public end date the calculated instead of the public end date and time has already been set.

  The invention according to claim 6 is a content distributed storage system comprising a plurality of node devices that can communicate with each other via a network, wherein duplicate data of a plurality of contents is distributed and stored in a plurality of node devices, A publication period control method for controlling the publication period for which each content can be used in a distributed content storage system in which the contents can be used between the node devices, and the number of the replicated data varies with time. A public period setting step in which the control device sets a public start date and time and a public end date and time for determining the public period; and the control device sets the copy data based on information collected from a plurality of the node devices. A copy data number calculating step for calculating the number of copies, and the control device responding to a lapse of time from the publication start date and time A publication end date and time calculation step for calculating the publication end date and time based on the transition of the number of data, and in the publication period setting step, the calculation is performed instead of the already set publication end date and time. The publication end date and time is reset.

  According to the present invention, a new publication end date is calculated based on the transition of the number of replicated data according to the passage of time from the set publication start date, and the calculation is performed in place of the already set publication end date. Since it is configured to reset the published end date and time, it is possible to efficiently control and manage the publication period reflecting the change in the content usage demand.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, the best embodiment of the invention will be described with reference to the drawings. The embodiment described below is an embodiment when the present invention is applied to a content distributed storage system.

[ 1. Configuration of distributed content storage system ]
First, with reference to FIG. 1 etc., the structure and operation | movement outline | summary of the content distribution preservation | save system which concern on this embodiment are demonstrated.

  FIG. 1 is a diagram showing an example of a connection mode of each node device in the distributed content storage system according to this embodiment.

  As shown in the lower frame 101 of FIG. 1, IX (Internet eXchange) 3, ISP (Internet Service Provider) 4a, 4b, DSL (Digital Subscriber Line) line operators (devices) 5a, 5b, FTTH (Fiber To A network (real-world communication network) 8 such as the Internet is constructed by a line provider (device) 6 and a communication line (for example, a telephone line or an optical cable) 7. Note that a router for transferring data (packets) is appropriately inserted into the network 8 in the example of FIG.

  A plurality of node devices (hereinafter referred to as “nodes”) Nn (n = 1, 2, 3,...) Are connected to such a network 8. Each node Nn is assigned a unique manufacturing number and an IP (Internet Protocol) address. The content distributed storage system S according to the present embodiment is a peer-to-peer network system formed by participation of any of a plurality of nodes Nn, as shown in the upper frame 100 of FIG. It has become.

  A network 9 shown in the upper frame 100 of FIG. 1 is an overlay network 9 (logical network) that forms a virtual link formed using the existing network 8. Such an overlay network 9 is realized by a specific algorithm, for example, an algorithm using DHT. Each node Nn participating in the content distributed storage system S (in other words, the overlay network 9) is assigned a node ID, which is unique identification information having a predetermined number of digits. The node ID is, for example, a value (for example, the bit length is 160 bits) obtained by hashing an IP address or a manufacturing number individually assigned to each node Nn with a common hash function (for example, SHA-1). Yes, it will be distributed in one ID space without any bias.

  In addition, participation in the content distributed storage system S is performed by any node Nn (for example, the node N8) that has not participated in any node Nn (for example, a contact node that always participates in the system S) that has not participated. This is done by sending a participation message indicating a participation request.

  Each node Nn holds a routing table using DHT. This routing table defines the transfer destinations of various messages on the content distributed storage system S, specifically, a node including the node ID, IP address, and port number of a node Nn that is moderately separated in the ID space Multiple pieces of information are registered.

  One node Nn participating in the content distributed storage system S registers the minimum necessary node information of the nodes Nn among all the nodes Nn participating in the system S in the routing table, With respect to the node Nn that does not know (store) the node information, various messages are transferred between the nodes Nn to be delivered.

  Such a routing table using DHT is well known in Japanese Patent Application Laid-Open No. 2006-197400 and the like, and will not be described in detail.

  By the way, in the content distributed storage system S, replicas of various contents having different contents (for example, movies, music, etc.) are distributed (stored) in a plurality of nodes Nn in a predetermined file format. The replica can be used between Nn. For example, the node N5 stores a replica of the movie content with the title XXX, while the node N3 stores a replica of the movie content with the title YYY. (Hereinafter referred to as “content holding node”) and stored (for example, stored in a content storage area allocated to a part of a storage area such as a hard disk).

  Each of these content replicas includes information such as a content name (title), a content ID (identification information unique to each content), an evaluation value indicating evaluation of the content, and a disclosure period during which the content can be used. Is granted. This content ID is generated, for example, by hashing the content name + arbitrary numerical value (or may be the first few bytes of the content data) with a hash function common to obtaining the node ID (node ID and Placed in the same ID space). Alternatively, the system administrator may give a unique ID value (same bit length as the node ID) for each content. In this case, the content catalog information in which the correspondence between the content name and the content ID is written is distributed to all the nodes Nn.

  The evaluation value represents, for example, the popularity and importance of the content. For example, the evaluation value of content that is expected to be high is set higher when the content is input. The evaluation value is managed by each node Nn that stores the replica. The publication period is determined by the publication start date and time and the publication end date and time, and is set by the content management server SA at the time of input.

  In addition, the location of the replica of the content that is distributed and stored in this way, that is, the index information that includes the node information of the node Nn that stores the replica and the content ID of the content is the location of the replica of the content. Is stored (stored in the index cache) and managed by a node Nn (hereinafter referred to as “root node” or “root node of content (content ID)”) or the like.

  That is, the node information of the content holding node storing the content replica is managed by the root node so as to be provided in response to an inquiry from another node Nn.

  For example, the index information about the replica of the movie content with the title XXX is managed by the node N4 which is the root node of the content (content ID), and the index information about the replica of the movie content with the title YYY is Managed by the node N7 which is the root node of the content (content ID). Further, such a root node is determined to be, for example, a node Nn having a node ID closest to the content ID (for example, the higher-order digits match more).

  When a user of a certain node Nn wants to acquire a replica of the desired content, the node Nn that desires to acquire the replica (hereinafter referred to as “user node”) determines the content ID and the self of the content selected by the user. A content location inquiry (search) message (query) including the IP address of the client is generated and sent to another node Nn according to a routing table using its own DHT. That is, the user node sends a content location inquiry (search) message to the root node (to the root node) (inquires the location of the content replica to the root node). As a result, the content location inquiry (search) message finally arrives at the root node by DHT routing using the content ID as a key.

  Information such as the content name, content ID, and publication period of the content to be selected by the user at each node Nn is described in, for example, content catalog information distributed from the content management server SA to all the nodes Nn. . When the release start date / time comes after the content is input, the content to be acquired at each node Nn can be selected on the content catalog information (in other words, it cannot be selected on the content catalog information until the release start date / time), and the release ends. When the date and time arrives, the content cannot be selected on the content catalog information (for example, the content ID and content name of the content whose publication end date and time has arrived are deleted from the content catalog information).

  The content ID included in the content location inquiry (search) message may be generated by the user node by hashing the content name with the common hash function. The DHT routing is known in Japanese Patent Application Laid-Open No. 2006-197400 and the like, and thus detailed description thereof is omitted.

  The root node that receives the content location inquiry (search) message acquires index information corresponding to the content ID included in the content node from the index cache, and uses the index information as a user who is the transmission source of the content location inquiry message. Reply to the node. The user node that has acquired the index information in this way accesses the content holding node based on the IP address or the like of a certain content holding node included in the index information, and transmits a content transmission request message indicating the content request. It becomes possible to download (acquire) and reproduce a replica of the content.

  The root node transmits a content transmission request message to the content holding node indicated by the IP address or the like included in the index information, whereby the user node downloads the replica from the content holding node. You can also. The user node can also acquire the index information from a cache node that caches the same index information as the root node until the content location inquiry message reaches the root node.

  When there is no response from the root node or content holding node for a predetermined time due to network congestion or the like, the user node downloads the replica from the content distribution server that holds all content replicas.

  As described above, the content holding node that provided the replica of the content stored by the user node in response to the content request from the user node subtracts a predetermined value from the evaluation value of the content stored and managed by the content node (for example, The evaluation value is reduced by half). Further, the content holding node gives (transfers) the evaluation value corresponding to the subtraction to the user node that has received the replica of the content. The purpose of this is to divide the evaluation value by that amount because one piece of content has been duplicated.

  Then, the user node that has stored the replica downloaded from the content holding node in the content storage area publishes the content ID of the replica and its own node information in order to notify the root node that the replica has been stored ( Registration notification) message is generated, and the publish message is sent to the root node (to the root node).

  As a result, the publish message arrives at the root node by DHT routing using the content ID as a key, like the content location inquiry (search) message. Then, the root node registers (stores in the index cache area) index information including a set of node information and content ID included in the received publish message. In this way, the user node becomes a new content holding node that holds a replica of the content. In particular, since popular content is requested by many user nodes, the number of replicas stored in the content distributed storage system S gradually increases with time (in other words, stores replicas of the content). The number of content holding nodes increases).

  By the way, when the user node does not have enough free space in the content storage area to store the new replica to be downloaded, the user node determines the evaluation value of the content related to the replica and the already stored replica. The content with the lowest evaluation value is compared with the evaluation value of the content related to the content (if it is stored in plural, compared with the evaluation value of each content) and if the evaluation value of the content related to the new replica is not the lowest In this case, the replica of the content that has already been stored is deleted to secure a free space, and then the new replica is stored. Alternatively, the new replica is stored after the oldest content replica is deleted. Since the content that is not popular is deleted more frequently than the content that is downloaded to the user node, the number of replicas that can be used in the content distributed storage system S gradually decreases as time passes.

  As described above, in the distributed content storage system S according to the present embodiment, the number of replicas of each content varies with time. The number of replicas (replica amount) is managed for each content by the content management server SA.

[ 2. Configuration and function of content management server SA ]
Next, the configuration and function of the content management server SA (an example of a disclosure period control device) will be described with reference to FIG.

  FIG. 2 is a diagram illustrating a schematic configuration example of the content management server SA.

  As shown in FIG. 2, the content management server SA is controlled as a computer composed of a CPU having a calculation function, a working RAM, various data and a ROM for storing various data and programs (including the control processing program of the present invention). Unit 11, a storage unit 12 composed of an HD (hard disk) for storing and saving various data and various programs, a display unit 13 for displaying various types of information, and an instruction from an administrator, etc. An input unit 14 for giving an instruction signal corresponding to the instruction to the control unit 11 and a communication unit 15 for controlling communication of information with the node Nn and the like through the network 8 are configured. Are connected to each other via a bus 16. The control processing program may be downloaded from a predetermined server on the network 8, for example, or recorded on a recording medium such as a CD-ROM and read via the drive of the recording medium. You may make it.

  In the storage unit 12, a content information management database 121 and a replica number management database 122 are constructed.

  The content information management database 121 stores basic information of each content input to the content distributed storage system S. The basic information includes, for example, information such as a content ID, a content name, a publication start date / time, and a publication end date / time.

  The replica number management database 122 stores the number of replicas of each content input to the content distributed storage system S.

  In such a configuration, the control unit 11 performs overall control by reading and executing a program (including the control processing program of the present invention) stored in the storage unit 12 or the like by the CPU, and is disclosed in the present invention. It functions as a period setting unit, a replicated data number calculation unit, a disclosure end date calculation unit, a display control unit, a reception unit, a disclosure end date information notification unit, and the like.

  More specifically, when the control unit 11 inputs new content to the content distributed storage system S (that is, transmits the content to any one or more nodes Nn for storage), the control unit 11 releases the content and starts publishing the content. Set the end date and time. The publication start date and time and the publication end date, in other words, the publication period is set in consideration of, for example, the expected number of accesses (popularity) to the content. The publication start date and time and the publication end date thus set are stored in the content information management database 121 together with the content ID of the content.

  The control unit 11 repeatedly calculates the number of replicas of each content every predetermined time based on information collected from the plurality of nodes Nn. For example, each node Nn participating in the content distributed storage system S periodically transmits log information such as a content replica download history and reproduction history to the content management server SA. Alternatively, each node Nn periodically transmits the log information to the root node of the corresponding content, and each root node transmits the log information collected from each node Nn to the content management server SA. You may comprise so that it may do. The control unit 11 can obtain the number of replicas of each content in the content distributed storage system S from the log information collected in this way. The replica number calculated in this way is stored in the replica number management database 122 together with the calculation time and the content ID.

  Then, the control unit 11 calculates a new release end date and time based on the change in the number of replicas according to the passage of time from the set release start date and time, and the already set release end date and time. An optimization index, which is the difference from the new release end date, is calculated.

  FIG. 3 is a diagram showing the transition of the number of replicas of contents A and B over time.

  In the example of FIG. 3, the solid line indicates the change (curve) of the number of replicas actually calculated from the publication start date and time to the current date and time, and the broken line indicates the change (curve) of the number of replicas estimated after the current date and time. Show. The replica number variation curve thus estimated can be calculated based on, for example, the slope of the solid line portion. As a result, it is estimated that the content A has no viewing demand at the X1 point (predicted date and time when the number of replicas converges (in this example, 0)) before the set release end date and time. Is calculated as the new release end date and time (calculated at the current date and time). On the other hand, it is estimated that there is a viewing demand for the content B even after the set publication end date and time, and it is estimated that the viewing demand disappears at the point X2 after the publication end date and time. Calculated as end date and time (calculated at the current date and time).

  For example, the number of days (T1 and T2 in the figure) that is the difference between the new publication end date and time calculated in this way and the already set publication end date and time is calculated as an optimization index (calculated at the time of the current date and time). It is. Here, for the content A, since a new release end date / time comes before the already set release end date / time, the optimization index is represented by minus (−). On the other hand, for the content B, since a new release end date / time comes after the already set release end date / time, the optimization index is represented by plus (+).

Incidentally, the calculation of the optimization index is executed at a predetermined time interval (for example, every hour). At this time, content that does not meet any of the following conditions (a) to (e) is a target for calculating the optimization index.
(A) Current date and time <Publication start date and time (b) Current date and time> Date of publication end date and time already set (c) | Current date and time-Publication start date and time | is a predetermined% (for example, 10%) of the publication period (Because the data required for calculation cannot be obtained)
(D) No more than a predetermined period (for example, 10%) of the publication period has elapsed since the date and time when the number of replicas became maximum (e) The number of replicas is the minimum value after the date and time when the number of replicas became maximum The minimum value is not updated after a predetermined period (for example, 10%) or more of the publication period has elapsed since the date and time when the record was recorded (because the curve trend may have changed)

  Since the optimization index is calculated based on a curve where the number of replicas converges, the optimization index cannot be calculated for content in which the number of replicas is increasing. Under the conditions (d) and (e), the number of replicas tends to increase, so the date and time when the number of replicas converges cannot be predicted. However, in the case of such contents, when | current date-release start date | is 90% or more of the publication period, for example, the optimization index is calculated as a certain positive value (for example, 50% of the publication period is calculated). It is desirable to extend the publication end date by calculating as a plus optimization index.

Here, an example of a calculation process until the optimization index is calculated will be described.
For example,
Dto = Date and time of publication set already set Dmax = Date and time when the number of replicas recorded the maximum value Dnow = Current date and time Rmax = Number of replicas at the time of Dmax Rnow = Number of replicas at the current date and time (Rmax> Rnow)
x = elapsed time from the current date and time until the number of replicas converges [seconds]
y = Date and time when the number of replicas is expected to converge (new release end date and time)
Then,
Rnow + ((Rnow−Rmax) / (Dnow−Dmax)) * x = 0 (1)
The following relational expression holds. Note that Dto, Dmax, and Dnow are substituted into the calculation formula, for example, in the elapsed [seconds] from 1970/1/1 0:00:00 (because it is suitable for calculation on the program).

From the above equation (1), x = Rnow (Dnow−Dmax) / (Rmax−Rnow)
It becomes.

  Then, y = Dnow + x, and the optimization index = y−Dto.

  As described above, when calculating the optimization index, the control unit 11 displays the optimization index and the like of each content on the screen of the management IF in the display unit 13.

  FIG. 4 is a diagram illustrating an example of a management IF screen.

  In the screen example shown in FIG. 4, the content ID, content name, publication deadline (publication end date and time), number of replicas, and optimization index of each content are listed, and next to each optimization index, “ The “Optimize” button B is displayed.

  In such a display state, the administrator as the user operates the input unit 14 to designate the “optimization” button B of the desired content (for example, align the pointer and click with the mouse) to reset the instruction. Then, the control unit 11 receives the reset instruction, and resets the calculated new publication end date and time instead of the already set publication end date and time. For example, the control unit 11 deletes the already set release end date and time of the content and registers the calculated new release end date and time in the content information management database 121, and also registers the content ID and the new release date. The end date and time is described (set) in the publication deadline change list, or is described in the content catalog information scheduled to be distributed next time.

  As a result, the administrator can check or judge the displayed optimization index and then extend or shorten the publication end date if necessary. For example, if the optimization index is small, the administrator will not reset it. It can also be.

  For example, when the “optimization” button B of the content with the content ID “00000002” is designated, the date and time corresponding to the “−10” day from the previously set release end date and time is reset as the new release end date and time.

  Note that the control unit 11 calculates the new publication end date and time instead of the already set publication end date and time each time the new publication end date and time are calculated, even if there is no resetting instruction from the user. May be configured to be reset (automatic reset), and according to this configuration, it is possible to extend or shorten the disclosure end date and time without the administrator confirming the optimization index.

  Then, when the resetting is performed or when the set time comes, the control unit 11 participates in the content distributed storage system S with the information indicating the reset end date and time and the corresponding content ID. To the plurality of nodes Nn. For example, the reopening end date / time and the content expiration information list in which the corresponding content ID is described or the content catalog information is distributed to each node Nn. If such distribution is performed by, for example, DHT multicast (multicast message transfer processing) disclosed in Japanese Patent Application Laid-Open No. 2007-053662, all nodes Nn participating in the content distributed storage system S are distributed. It is desirable because it can be distributed efficiently.

[ 3. Configuration and function of node Nn ]
Next, the configuration and function of the node Nn will be described with reference to FIG.

  FIG. 5 is a diagram illustrating a schematic configuration example of the node Nn.

  As shown in FIG. 5, each node Nn includes a control unit 21 composed of a CPU having an arithmetic function, a working RAM, a ROM for storing various data and programs, and various data (for example, a replica of content data, Index information, DHT, etc.) and a storage unit 22 composed of an HD (hard disk) for storing and storing various programs, a buffer memory 23 for temporarily storing received content data replicas, etc. A decoder unit 24 that decodes (data expansion, decoding, etc.) encoded video data (video information) and audio data (audio information) included in the replica, and a predetermined drawing for the decoded video data, etc. Video processing unit 25 that performs processing and outputs the video signal, and the video processing A display unit 26 such as a CRT or a liquid crystal display for displaying an image based on the video signal output from 25, and the decoded audio data is converted into an analog audio signal by D (Digital) / A (Analog) and then this is amplified by an amplifier. Communication of information between the audio processing unit 27 that amplifies and outputs, the speaker 28 that outputs the audio signal output from the audio processing unit 27 as a sound wave, and the other nodes Nn and the content management server SA through the network 8 A communication unit 29 for performing control, and an input unit 30 (for example, a keyboard, a mouse, or an operation panel) that receives an instruction from the user and provides an instruction signal corresponding to the instruction to the control unit 21. A control unit 21, a storage unit 22, a buffer memory 23, a decoder unit 24, a communication unit 29, and an input. Part 30 is connected to each other via a bus 31. As the node Nn, a personal computer, an STB (Set Top Box), a TV receiver, or the like can be applied.

  The storage unit 22 stores the content catalog information described above. Further, an evaluation value management table for registering information such as a content ID corresponding to a replica stored in the storage unit 22 and an evaluation value of the content is stored in the storage unit 22.

  In such a configuration, the control unit 21 performs overall control by reading and executing a program stored in the storage unit 22 or the like by the CPU, and the above-described user nodes by participating in the content distributed storage system S, Processing as at least one of a relay node, a root node, a cache node, and a content holding node is performed.

  Further, the information indicating the new release end date and the corresponding content ID notified from the content management server SA to the node Nn is reflected in each node Nn, that is, the release end date is updated on the content catalog information.

[ 4. Operation of Content Distributed Storage System S ]
Next, the operation of the distributed content storage system S will be described.

  FIG. 6 is a flowchart showing processing of the control unit 11 in the content management server SA.

  The process of FIG. 6 is started automatically, for example, at a predetermined time interval (for example, every hour), or when a start instruction is given from the administrator via the input unit 14. When the processing of FIG. 6 is started, the control unit 11 receives information indicating the transition of the content ID, the publication start date / time, the publication end date / time, and the number of replicas from the content information management database 121 and the replica number management database 122 for each content. (Step S1), and it is determined whether there is content for which the optimization index is calculated (step S2). For example, if there is content that does not meet any of the above conditions (a) to (e), it is determined that there is content for which an optimization index is to be calculated (step S2: YES), and the process proceeds to step S3. If there is no content that does not meet any of the conditions, it is determined that there is no content for which an optimization index is to be calculated (step S2: NO), and the process ends.

  In step S3, the control unit 11 specifies one of the contents for which the optimization index is calculated.

  Next, as described above, the control unit 11 calculates a new publication end date and time based on the change in the number of replicas according to the passage of time from the publication start date and time of the identified content (step S4), and temporarily stores the RAM. Remember it.

  Next, the control unit 11 determines whether there is content that has not been specified in step S3 (step S5). If there is content that has not been specified yet (step S5: YES), the control unit 11 returns to step S3. The content not yet specified is specified and the same processing as above is performed. On the other hand, if there is no content not specified in step S3 (step S5: NO), the process proceeds to step S6.

  In step S6, the control unit 11 determines whether or not automatic resetting is selected. If automatic resetting is not selected (step S6: NO), the control unit 11 proceeds to step S7 and performs automatic resetting. If it is selected (step S6: YES), the process proceeds to step S12. Note that the selection of the automatic resetting is made by the administrator in advance as an initial setting, for example.

  In step S7, the control unit 11 calculates an optimization index that is the difference between the already set release end date and time of each content for which the new release end date has been calculated and the calculated new release end date and time. To do.

  Next, the control unit 11 displays the calculated optimization index and the like of each content on the management IF screen in the display unit 13 as shown in FIG. 4 (step S8).

  Next, the control unit 11 determines whether or not the “optimization” button B displayed on the management IF screen is designated (step S9), and when the “optimization” button B is designated. (Step S9: YES), accepts the reset instruction, and resets the calculated new publication end date and time instead of the already set publication end date and time of the content corresponding to the button B (Step S10). Return to step S9.

  On the other hand, when the “optimization” button B is not designated (step S9: NO), the control unit 11 determines whether or not there is a resetting end instruction (step S11), for example, an input unit from the administrator. If there is a reset end instruction via 14 (step S11: YES), a notification process of the reset end date is performed (step S13), and the process ends. On the other hand, if there is no end instruction (step S11: NO), the process returns to step S9.

  In step S12, the control unit 11 resets the calculated new publication end date and time in place of the already set publication end date and time for each content for which the new publication end date and time has been calculated. move on.

  Then, in the notification process in step S13, as described above, the control unit 11, for example, displays the release date change list in which the reset end date and time and the corresponding content ID are described, or the content catalog information for each node Nn. Deliver against. Note that such distribution may be performed not by the content management server SA but by a content distribution server that holds replicas of all content.

  Thus, the information indicating the new release end date and the corresponding content ID notified to each node Nn is reflected in each node Nn, that is, the release end date is updated on the content catalog information (update Whether or not the user can select the content is determined based on the date and time when the publishing ends later).

  Note that the content holding node that stores the replica of the content whose publication end date has passed deletes the replica. For example, the content holding node refers to the distributed content catalog information, searches for content whose current date and time has passed the publishing end date and deletes the replica. Alternatively, the content holding node deletes the replica of the content from which the information such as the content ID has been deleted from the content catalog information (deleted by the content management server SA since the publication end date has passed). Alternatively, the content holding node deletes the replica when receiving a deletion request from the content management server SA or the root node of the content whose publication end date has passed. Further, the replica of the content after the publication end date and time is also deleted from the content distribution server.

  As described above, according to the above embodiment, the content management server SA calculates a new publication end date and time based on the transition of the number of replicas according to the passage of time from the set publication start date and time, and has already been set. Since the calculated publication end date / time is reset in place of the published end date / time, it is possible to efficiently control and manage the publication period reflecting the change in the viewing demand of the content.

  In addition, by resetting the publishing end date according to the change in the number of replicas, it is not necessary to wastefully store content that is not in use at the content holding node or content distribution server that stores the content replica until the publishing end date Therefore, the storage capacity of a hard disk or the like can be reduced and used efficiently.

  In addition, the content management server SA calculates an optimization index that is the difference between the already set publication end date and time and the calculated new publication end date and time, and displays the optimization index and the like on the management IF screen. According to the configuration in which the calculated release end date / time is reset in place of the already set release end date / time when there is a reset instruction from the administrator, the administrator After confirming and determining the optimization index, if necessary, the publication end date can be extended or shortened. For example, if the optimization index is small, it may not be reset. Furthermore, by efficiently calculating and reflecting the optimization index, it is possible to efficiently manage the content that always reflects the change in the viewing demand of the content.

  In addition, although the content distributed storage system S in the said embodiment was demonstrated on the assumption that it was formed by the algorithm using DHT, this invention is not limited to this.

It is a figure which shows an example of the connection aspect of each node apparatus in the content distributed storage system which concerns on this embodiment. It is a figure which shows the example of a schematic structure of content management server SA. It is a figure which shows transition of the replica number of the contents A and B according to time passage. It is a figure which shows an example of the screen of management IF. It is a figure which shows the example of an outline structure of the node Nn. It is a flowchart which shows the process of the control part 11 in content management server SA.

Explanation of symbols

8 Network 9 Overlay Network 11 Control Unit 12 Storage Unit 13 Display Unit 14 Input Unit 15 Communication Unit 16 Bus 21 Control Unit 22 Storage Unit 23 Buffer Memory 24 Decoder Unit 25 Video Processing Unit 26 Display Unit 27 Audio Processing Unit 28 Speaker 29 Communication Unit 30 input unit 31 bus SA content management server Nn node S content distributed storage system

Claims (6)

A distributed content storage system comprising a plurality of node devices that can communicate with each other via a network, wherein copy data of a plurality of contents is distributed and stored in a plurality of node devices, and the content is used between the node devices A public period control device that controls the public period during which content can be used in a content distributed storage system in which the number of replicated data varies with time,
A publication period setting means for setting a publication start date and a publication end date and time for determining the publication period;
Replicated data number calculating means for calculating the number of replicated data based on information collected from a plurality of the node devices;
A publication end date and time calculating means for calculating the publication end date and time based on the transition of the number of the replicated data according to the passage of time from the publication start date and time;
With
The public period control device, wherein the public period setting means resets the calculated public end date and time instead of the public end date and time that has already been set. In the disclosure period control device according to claim 1,
Display control means for displaying a difference between the public end date and time already set and the calculated public end date and time;
A receiving means for receiving a resetting instruction from the user;
Further comprising
The publication period control device, wherein the publication period setting means resets the publication end date and time when the reset instruction is given. In the disclosure period control device according to claim 1 or 2,
A publication period control device, further comprising a publication completion date and time information notifying unit for notifying the plurality of node devices of information indicating the reset publication completion date and time.   A control processing program for causing a computer to function as the disclosure period control device according to any one of claims 1 to 3. A distributed content storage system comprising a plurality of node devices that can communicate with each other via a network, wherein copy data of a plurality of contents is distributed and stored in a plurality of node devices, and the content is used between the node devices In a content distributed storage system in which the number of replicated data varies over time,
A public period control device that controls the public period during which content can be used for each content.
A publication period setting means for setting a publication start date and a publication end date and time for determining the publication period;
Replicated data number calculating means for calculating the number of replicated data based on information collected from a plurality of the node devices;
A publication end date and time calculating means for calculating the publication end date and time based on the transition of the number of the replicated data according to the passage of time from the publication start date and time;
With
The content distribution storage system, wherein the publication period setting means resets the calculated publication end date and time instead of the already set publication end date and time. A distributed content storage system comprising a plurality of node devices that can communicate with each other via a network, wherein copy data of a plurality of contents is distributed and stored in a plurality of node devices, and the content is used between the node devices A publication period control method for controlling the publication period for which the content can be used in the content distributed storage system in which the number of the replicated data varies with time,
A control period, a publication period setting step for setting a publication start date and time and a publication end date and time for determining the publication period;
The control device calculates the number of replicated data based on information collected from the plurality of node devices,
The control device calculates a publication end date and time to calculate the publication end date and time based on a transition of the number of the duplicate data according to the passage of time from the publication start date and time,
Including
In the publication period setting step, the calculated publication end date and time is reset in place of the already set publication end date and time.

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