JP2010026866A - Content distribution storage system, total evaluation value management device, management processing program, node device and total evaluation value management method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a content distribution storage system, a total evaluation value management device, a management processing program, a node device and a total evaluation value management method, allowing rapid and high-accuracy investigation of a total evaluation value of an already disclosed content. <P>SOLUTION: In this content distribution storage system, the total evaluation value management device selects one node device from a plurality of node devices participating in the content distribution storage system, transmits request information showing a request for an evaluation value of the content to the selected node device, receives evaluation value information showing the evaluation value of the content corresponding to duplicate data stored by the node device from the node device, acquires a total evaluation value of the content shown in the received evaluation value information from a total evaluation value storage means, and calculates a new total evaluation value based on the acquired total evaluation value of the content and the total evaluation value of the content shown in the received evaluation value information. <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.

  In such a content distributed storage system, if the number of replicas stored and distributed in the system (each node device) is too small before the content can be used (before publication), There is concern that access will be concentrated on the replica after the release. On the other hand, when the number of replicas is too large, there is a concern that the storage area for storing replicas in each node device is wasted and results in the storage area being compressed. Therefore, it is desirable that a number of replicas corresponding to popularity are distributed and stored in the system before publication, and then the contents are made available to other node devices for use.

In Patent Literature 1, each node device has an evaluation value of the content before the publication (for example, representing the popularity of the content) and a previously saved content before the content to be newly input to the system is published. The content is compared with the evaluation value, and when the evaluation value of the pre-release content is large, it is stored, but when it is small, it is not stored.
JP 2007-034630 A

  By the way, in order to determine the initial total evaluation value of the pre-release content, for example, a method of predicting the popularity by pre-publishing to a limited number of node devices is conceivable. There is a problem that it takes time and effort.

  Moreover, based on the total evaluation value of the published content, the total evaluation value of the pre-published content is close to the total evaluation value of the same published content (the total of the evaluation values managed by each node device). Thus, it is conceivable to predict the initial total evaluation value of the pre-release content. Here, “similar published content” refers to, for example, a previous work of a series in a movie or a past work of the same artist in music.

  However, since content replicas are distributed and stored in a plurality of node devices, if you want to examine the total evaluation value of any content, you must investigate all the node devices that store the content replicas. As the number of node devices increases, there is a problem that the investigation takes a lot of time and cost.

  Further, in a system in which a replica of a certain content is divided and stored in a plurality of caches, it is necessary to obtain the total evaluation value of each cache in order to obtain the total evaluation value of the content, and the number of divided caches increases. This also increases the system load.

  In addition, the fact that the total evaluation value of the content cannot be obtained means that the popularity of the content cannot be known. In other words, for example, when the popularity ranking representing the popularity ranking of the content is to be created, this cannot be done. is there.

  The present invention has been made in view of the above points and the like, and is a content distributed storage system, a total evaluation value management apparatus, a management processing program, and a node capable of quickly and accurately examining a total evaluation value of published content It is an object to provide an apparatus and a total evaluation value management method.

  In order to solve the above-described problem, the invention according to claim 1 is a distributed content storage system configured by participation of a plurality of node devices connected to a network, and a plurality of pieces of replicated data of a plurality of contents are a plurality of node devices. In the content distributed storage system, the evaluation value indicating the evaluation of the content is managed by each of the node devices stored in a distributed manner and the total evaluation value indicating the sum of the evaluation values is stored in the content. A total evaluation value management device for managing each of the contents, total evaluation value storage means for storing the total evaluation value of each content, and any one of the plurality of node devices participating in the content distributed storage system Node device selection means for selecting the content evaluation value of the content for the selected node device. Request information transmitting means for transmitting request information indicating a request, and evaluation value information indicating an evaluation value of content corresponding to duplicate data stored in the node device that has received the request information are received from the node device. Evaluation value information receiving means, total evaluation value acquisition means for acquiring the total evaluation value of the content indicated in the received evaluation value information from the total evaluation value storage means, the total evaluation value of the acquired content, and the received Total evaluation value calculation means for calculating a new total evaluation value based on the evaluation value of the content indicated in the evaluation value information, and the previous time stored in the total evaluation value storage means by the total evaluation value of the newly calculated content And a total evaluation value updating means for updating the total evaluation value of the content.

  According to the present invention, the total evaluation value management device selects any one of the plurality of node devices participating in the distributed content storage system, and the content for the selected node device. Request information indicating a request for an evaluation value, and receiving from the node device evaluation value information indicating an evaluation value of content corresponding to the copy data stored in the node device that has received the request information, The total evaluation value of the content indicated in the received evaluation value information is acquired from the total evaluation value storage means, the total evaluation value of the acquired content, the total evaluation value of the content indicated in the received evaluation value information, A new total evaluation value is calculated based on the previous evaluation value stored in the total evaluation value storage means based on the newly calculated total evaluation value of the content. Since it is configured to update the general comment value Ntsu, even if large number of node devices, without the can take a lot of time and cost to the survey, the general comment value of content can be quickly investigated.

  According to a second aspect of the present invention, in the total evaluation value management device according to the first aspect, the total evaluation value calculating means uses the total evaluation value of the acquired content as the total number of node devices participating in the content distributed storage system. Is multiplied by the number obtained by subtracting the number of node devices that transmitted the evaluation value information from the total number, and the multiplied value and the evaluation of the content indicated in the received evaluation value information And adding the value to calculate the new total evaluation value.

  According to the present invention, even if the number of node devices increases, the total evaluation value of the content can be investigated quickly and accurately without taking much time and cost for the investigation.

  According to a third aspect of the present invention, in the total evaluation value management device according to the first or second aspect, the node device selection means is any one of the plurality of node devices participating in the content distributed storage system. One node device is selected at random.

  The invention according to claim 4 is the total evaluation value management device according to any one of claims 1 to 3, wherein the node device selection means, the request information transmission means, the evaluation value information reception means, and the total evaluation value. A series of processes by the acquisition unit, the total evaluation value calculation unit, and the total evaluation value update unit are repeatedly executed at predetermined time intervals.

  According to the present invention, the latest total evaluation value can be investigated at predetermined time intervals.

  According to a fifth aspect of the present invention, in the total evaluation value management device according to any one of the first to fourth aspects, when a total evaluation value of new content is calculated by the total evaluation value calculating unit, the new evaluation value And a total evaluation maximum value calculating means for comparing the total evaluation value of the correct content with the total evaluation value of the previous content and obtaining the larger one as the maximum value of the total evaluation value.

  According to the present invention, content can be evaluated from various viewpoints.

  The invention according to claim 6 is the total evaluation value management device according to any one of claims 1 to 5, each time the total evaluation value of the new content is calculated by the total evaluation value calculation unit. And a total evaluation average value calculating means for calculating an average value of each of the total evaluation values for the specific content stored within a predetermined period.

  According to the present invention, content can be evaluated from various viewpoints.

  The invention according to claim 7 is the total evaluation value management device according to any one of claims 1 to 6, wherein the total evaluation value of each content, the maximum value of the total evaluation value of each content, or the The apparatus further comprises ranking determining means for determining a ranking representing the popularity ranking of the content based on the average value of the total evaluation values.

  According to the present invention, it is possible to efficiently determine a ranking representing the popularity ranking of content.

  The invention according to claim 8 is the total evaluation value management device according to any one of claims 1 to 7, wherein the total evaluation value management apparatus has at least one content keyword to which the total evaluation value is not given, and the total evaluation value Content specifying means for specifying the content to which is given, and the total evaluation value calculating means calculates the total evaluation value of the content to which the total evaluation value is not given based on the total evaluation value of the specified content It is characterized by that.

  According to the present invention, it is possible to predict (estimate) the popularity of pre-release content relatively easily without requiring the system administrator to take time.

  A ninth aspect of the present invention is the total evaluation value management apparatus according to any one of the first to eighth aspects, wherein the content distributed storage system divides the duplicate data of one content into a plurality of pieces. Is distributed and stored in the plurality of node devices, and each node device storing the divided copy data is assigned and managed with an evaluation value representing the evaluation of the content having the divided copy data. The evaluation value information receiving means is configured such that the divided duplicate data stored in the node device that has received the request information is a part of all the divided duplicate data constituting the content corresponding thereto. The evaluation value information indicated by the average value of the evaluation values assigned to the partial divided copy data as the evaluation value of the content is stored in the node device. Characterized by receiving from.

  According to the present invention, even if the number of divided duplicate data increases, the total evaluation value of the contents can be quickly investigated without increasing the system load.

  The invention according to claim 10 is a node device that has received the request information transmitted from the total evaluation value management device according to claim 9, and is an average of evaluation values given to the partial divided duplicate data Evaluation value information indicating a value as an evaluation value of the content is transmitted to the total evaluation value management apparatus.

  An invention of a management processing program according to an eleventh aspect causes a computer to function as the total evaluation value management apparatus according to any one of the first to ninth aspects.

  The invention according to claim 12 is a content distributed storage system configured by participation of a plurality of node devices connected to a network, wherein duplicate data of a plurality of contents are distributed and stored in a plurality of node devices, Total evaluation value management for managing, for each content, a total evaluation value representing the total sum of the evaluation values in a distributed content storage system in which evaluation values representing the evaluation of the content are managed by each of the node devices storing duplicate data An apparatus includes a total evaluation value storage unit that stores a total evaluation value of each content, a node device selection unit that selects any one of the plurality of node devices participating in the content distributed storage system, Request information indicating a request for the evaluation value of the content is transmitted to the selected node device. The evaluation value information receiving means, the evaluation value information receiving means for receiving the evaluation value information indicating the evaluation value of the content corresponding to the duplicate data stored in the node device that has received the request information, and the node device, Total evaluation value acquisition means for acquiring the total evaluation value of the content indicated in the received evaluation value information from the total evaluation value storage means, the total evaluation value of the acquired content, and the content of the content indicated in the received evaluation value information Total evaluation value calculating means for calculating a new total evaluation value based on the evaluation value, and updating the total evaluation value of the previous content stored in the total evaluation value storage means with the total evaluation value of the newly calculated content And a total evaluation value updating means.

  The invention according to claim 13 is a content distributed storage system configured by participation of a plurality of node devices connected to a network, wherein duplicate data of a plurality of contents are distributed and stored in a plurality of node devices, A total evaluation value management method for content in a distributed content storage system in which an evaluation value representing an evaluation of the content is managed by each of the node devices storing duplicate data, the total evaluation value representing a sum of the evaluation values The total evaluation value management device that manages the content for each content selects one of the node devices among the step of storing the total evaluation value of each content and the plurality of node devices participating in the content distributed storage system. Request information indicating a request for the evaluation value of the content to the process and the selected node device A step of transmitting, a step of receiving, from the node device, evaluation value information indicating an evaluation value of content corresponding to the copy data stored in the node device that has received the request information, and the received evaluation value A new total evaluation value of the content indicated in the information is acquired from the total evaluation value storage means, the total evaluation value of the acquired content, and the evaluation value of the content indicated in the received evaluation value information. And a step of updating the total evaluation value of the previous content stored in the total evaluation value storage means with the newly calculated total evaluation value of the content.

  According to the present invention, the total evaluation value management device selects any one of the plurality of node devices participating in the distributed content storage system, and the content for the selected node device. Request information indicating a request for an evaluation value, and receiving from the node device evaluation value information indicating an evaluation value of content corresponding to the copy data stored in the node device that has received the request information, The total evaluation value of the content indicated in the received evaluation value information is acquired from the total evaluation value storage means, the total evaluation value of the acquired content, the total evaluation value of the content indicated in the received evaluation value information, A new total evaluation value is calculated based on the previous content stored in the total evaluation value storage means based on the newly calculated total evaluation value of the content. Since it is configured to update the general comment value of Tsu, even if large number of node devices, without the can take a lot of time and cost to the survey, the general comment value of content can be quickly investigated.

  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 and the like, a schematic configuration and the like of the content distributed storage system according to the present embodiment will be described.

  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 via a router. 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 nodes”).

  Each of these content replicas is given information such as a content name (title), a content ID (identification information unique to each content), and an evaluation value indicating evaluation of the content. 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 or importance of the content. For example, a highly popular content has a high evaluation value. The evaluation value is managed by each node Nn that stores the replica.

  In addition, the location of the replica stored in this manner, that is, the index information including the set of the node information of the node Nn storing the replica and the content ID corresponding to the replica of the content is 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 data (content ID)”) that manages the location of

  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”) is the content selected by the user from content catalog information, for example. A content location inquiry (search) message (query) including the content ID and its own IP address is generated and sent to another node Nn according to the routing table using its own DHT. That is, the user node sends a content location inquiry (search) message toward the root node (to the root node) (that is, 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.

  Note that the attribute information such as the content name, content ID, and publication date of the content to be selected by the user in each node Nn is described in, for example, content catalog information distributed from the content providing server to all the nodes Nn. Here, the release date and time indicates the date and time when the content can be used in each node Nn. For example, the release date / time is the date / time at which the content to be acquired in each node Nn can be selected on the content catalog information (until the release date / time cannot be selected on 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 connects to the content holding node based on the IP address of the content holding node included in the index information, transmits a content transmission request message, and then creates a replica of the content from there. Obtain (download).

  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 acquires 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.

  Further, as described above, the content holding node that provided the replica of the content stored by itself 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 holding 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. In addition, when content with a low evaluation value is deleted for downloading new content, the content holding node to be deleted transfers the evaluation value to another content holding node having the same content. It has become. Further, when the content holding node provides a content replica to the user node, the evaluation value of the content is slightly increased (for example, 1 is added), and then the evaluation value is subtracted by a predetermined value as described above ( For example, it is divided into two). As a result, the higher the number of downloads, the higher the total evaluation value. However, since the evaluation value is a mechanism that decreases with time, the total evaluation value of any content gradually decreases with time.

  In this way, the user node that has received the provision of a new content replica compares the evaluation value of the content related to the replica with the evaluation value of the content related to the replica that has already been stored (if a plurality of stored values are stored, respectively) For example, the replica with the lowest content evaluation value is deleted. Here, if the evaluation value of the content related to the replica is not the lowest, the replica is newly stored. Therefore, the higher the evaluation value of the transferred content, the higher the probability that the replica is stored in the user node, and the greater the number of replicas stored in the system S.

  Then, the user node that has stored the replica of the content acquired from the content holding node (for example, recorded on the hard disk) notifies the root node that the replica has been stored (in other words, participates in the system S). A publish (registration notification) message including the content ID of the replica and its own node information, and direct the publish message to the root node (to be disclosed to other nodes Nn) Send to 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.

  Note that the index information including the set of node information and content ID included in the publish message is also registered (cached) in the cache node in the transfer path to the root node.

  In the content distributed storage system S described above, the total evaluation value of each content is managed by a total evaluation value management server MS (an example of a total evaluation value management device). Here, the total content evaluation value represents the total sum of content evaluation values managed by the respective nodes Nn storing replicas of the target content. Such a total evaluation value can be accurately obtained by obtaining each evaluation value from all the nodes Nn that store replicas of the target content. In this case, however, if the number of nodes Nn increases, it takes a lot of time and cost. . Therefore, in the present embodiment, the total evaluation value management server MS acquires the evaluation values of the contents from some nodes Nn, so that the total evaluation values of the contents are totaled (calculated by an arithmetic expression described later), and the total evaluation value is calculated as the content. It is configured to manage each.

[ 2. Configuration and function of total evaluation value management server MS ]
Next, the configuration and function of the total evaluation value management server MS will be described with reference to FIG.

  FIG. 2 is a diagram illustrating a schematic configuration example of the total evaluation value management server MS.

  As shown in FIG. 2, the total evaluation value management server MS is a computer composed of a CPU having an arithmetic function, a working RAM, various data and programs (including a management processing program of the present invention), a ROM, and the like. A control unit 11, a storage unit 12 composed of an HD (hard disk) or the like for storing and saving various data and various programs, and a communication unit 13 for controlling communication of information between the nodes Nn and the like through the network 8. These are connected to each other via a bus 14. The management 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.

  The storage unit 12 stores a node management table (list) for registering node information of each node Nn participating in the content distributed storage system S. Each time the node Nn participates or withdraws from the distributed content storage system S, a message indicating this is transmitted, for example, from the node Nn that has joined or withdrawn to the total evaluation value management server MS, and the node management table is updated. It will be.

  The storage unit 12 stores a total evaluation value management table for registering information including the total evaluation value of each content. FIG. 3 is a diagram illustrating an example of information registered in the total evaluation value management table. As shown in FIG. 3, in the total evaluation value management table, a content ID, information on the latest total evaluation value, information on the maximum value of the total evaluation value, and evaluation value calculation history information are registered in association with each content. Yes. Here, the evaluation value calculation history information is necessary when the average of the total evaluation values is calculated by an arithmetic expression (3) to be described later, and is unnecessary when calculating by the arithmetic expression (4) (instead, the evaluation is performed for each content). Value survey count (t) is required).

  In addition, the latest total evaluation value includes the latest total evaluation value. The information on the maximum value of the total evaluation value includes the maximum value of the total evaluation value and the total number of nodes Nn participating in the content distributed storage system S at the time of calculation (hereinafter referred to as “total number of nodes”). ing. The evaluation value calculation history information includes a total evaluation value calculated in the past and the total number of nodes at the time of the calculation.

  In such a configuration, the control unit 11 performs overall control by reading and executing a program (including the management processing program of the present invention) stored in the storage unit 12 or the like by the CPU, and node device selection means , Request information transmission means, evaluation value information reception means, total evaluation value acquisition means, total evaluation value calculation means, total evaluation value update means, total evaluation maximum value calculation means, total evaluation average value calculation means, and ranking determination means.

  More specifically, in the aggregation (investigation) of the total evaluation value, first, the control unit 11 selects one of the nodes Nn participating in the content distributed storage system S (from the node management table). One Nn is selected at random, for example. It should be noted that the number of nodes Nn selected here is preferably determined according to the performance of the system and the required inspection accuracy because there is a trade-off between reducing the system load and improving the evaluation value inspection accuracy. .

  Next, the control unit 11 uses the node information of the selected node Nn to connect to this, and an evaluation value indicating a request for an evaluation value of content (for example, specified by a content ID) to the node Nn. A request message (an example of request information) is transmitted. The node Nn that has received the evaluation value request message receives the evaluation value response message (evaluation value information) indicating the content ID of the content (one or a plurality of different contents) corresponding to the replica stored by itself and the evaluation value thereof. An example) is returned to the total evaluation value management server MS.

Then, the control unit 11 receives the evaluation value response message returned from the node Nn. In this way, the control unit 11 can obtain the evaluation value of the content managed by the node Nn, and use this to calculate the approximate total evaluation value of the content by using, for example, the following arithmetic expression (1). it can.

Here, “v _t ” represents the total evaluation value of this time, “x _t ” represents the evaluation value acquired this time, and “n _t ” represents the total number of nodes.

In the present embodiment, it is assumed that the total number of nodes Nn storing the target content is not known. Therefore, “n _t ” is the total number of nodes Nn currently participating in the content distributed storage system S, and “x _t ” is considered to be 0 for content that the node Nn does not have. Therefore, it is necessary to investigate many times.

Assuming that “n _t ” is the total number of nodes Nn storing the target content, when calculating the maximum value of the total evaluation value or the average value of the total evaluation value, “a number of nodes Nn hold but each node Nn holds. When the evaluation value is low (when the evaluation value is used (for example, when creating a ranking)), it is not possible to cope with a case where “only a small number of nodes Nn are held but the evaluation value at each node Nn is high”. In other words, in this calculation formula (1), the evaluation value managed by one node Nn storing the replica of the content is the same for the other nodes Nn participating in the content distributed storage system S. It is assumed that there is.

However, in reality, the evaluation value varies among the nodes Nn, and thus may not be close to the actual total evaluation value. Therefore, the control unit 11 includes the latest total evaluation value (total evaluation value of the previous content) registered in the total evaluation value management table and the acquired evaluation value (the evaluation value indicated in the evaluation value response message). Based on this, for example, a new total evaluation value is calculated by the following arithmetic expression (2).

Here, “v _t-1 ” is the total evaluation value calculated last time (the latest total evaluation value registered in the total evaluation value management table), and “m _t ” is the number of nodes Nn that have transmitted the current evaluation value response message. (When node Nn is selected one by one, “1”) is shown.

That is, by such an arithmetic expression (2), an evaluation value (v _t-1 / _nt ) obtained by dividing the previously calculated total evaluation value v _t-1 by the current total node number n _t and the total node number The number (n _t −m _t ) obtained by subtracting the number m _t of the node Nn that has transmitted the evaluation value response message this time from n _t is multiplied by the multiplied value and the evaluation value x acquired this time _t and are added to calculate a new total evaluation value v _t . According to this arithmetic expression (2), it is possible to obtain a value close to the actual total evaluation value also by the above arithmetic expression (1) (approaching the actual total evaluation value at every aggregation).

Then, the control unit 11 updates the previous total evaluation value v _t−1 of the content registered in the total evaluation value management table with the newly calculated total evaluation value v _t of the content. Further, the control unit 11 newly registers (registers in the evaluation value calculation history information) the total evaluation value of the newly calculated content and the total number of nodes at the time of the calculation in the total evaluation value management table.

  A series of processes from selection of the node Nn to calculation and update of a new total evaluation value described above are repeatedly executed at predetermined time intervals (for example, periodically).

  Note that the content corresponding to the content ID not indicated in the evaluation value response message, that is, the content not stored in the selected node Nn is regarded as having acquired the evaluation value “0” and the new A total evaluation value is calculated.

  Such an example of a total evaluation value is a method for obtaining a total evaluation value at the present time. However, even if the total evaluation value at the time of publication is high, content whose total evaluation value decreases as time passes can be considered. For example, for a movie series with the title XXX, the total evaluation value when the first work is released is very high, but the total evaluation value of the first work is low when the second work is released. is expected. Therefore, if the total evaluation value of the first work at the time of release is referred to the second work, a sufficient total evaluation value may not be attached. In order to solve this problem, in addition to obtaining the total evaluation value at the present time, the maximum value of the total evaluation value from the release to the present and the average value of the total evaluation values within a predetermined period after the release are obtained.

For example, when the new total evaluation value v _t is calculated, the control unit 11 compares the new total evaluation value v _t with the previous total evaluation value v _t−1 to obtain the larger one as the maximum value of the total evaluation value, The maximum value of the total evaluation value registered in the total evaluation value management table and the total number of nodes at the time of calculation are updated based on the maximum value and the current total number of nodes. That is, the maximum value of the total evaluation value of the content in time series is always held, and the maximum value is updated when the maximum value is exceeded during the above-described total evaluation value aggregation. As a result, the system administrator or the like can grasp the total evaluation value of the content when it is most popular. Note that the total number of nodes at the time of calculation is registered in association with the maximum value of the total evaluation value if the total number of nodes is different between the past time point when the total evaluation value of the published content is calculated and the present time. Since it is not possible to know whether the value is high or low, by registering the total number of nodes at the time of calculation, the difference in the total evaluation value due to the change in the total number of nodes is compensated.

  Further, as described above, every time the total evaluation value of new content is calculated, the total evaluation value and the like are separately registered in the evaluation value calculation history information. An average value of each total evaluation value for a specific content registered within a certain period) is calculated and registered in, for example, a total evaluation value management table. As a result, the system administrator or the like can grasp how popular the specific content is within a certain period of time after the release, for example.

The average of the total evaluation values can be calculated by the following arithmetic expression (3).

Here, "v _av" is the average value of the total evaluation value, "v _i" is i (i is, 1~t) a general comment value has been calculated by the time of the investigation, "t" is the number of times the calculation of the total evaluation value ( The number of surveys). As described above, it is preferable to use “v _i ” calculated by the calculation formula (2) rather than the calculation formula (1). Instead of each total evaluation value v _i , the evaluation value x _i acquired in each survey and the total number of nodes n _i at that time may be stored.

By the way, since it may not be desirable in terms of storage capacity and cost to actually hold the total evaluation values for t times as evaluation value calculation history information, the control unit 11 acquires an evaluation value from the node Nn. In addition, the average of the total evaluation values may be recalculated by the following arithmetic expression (4).

Here, “v _av-1 ” represents the average value of the total evaluation values calculated last time. By using this calculation formula (4), instead of the general comment value v _i of t times, so that sufficient by storing a general comment value v _av-1 calculated in the previous survey.

  However, in this arithmetic expression (4), for example, it is also necessary to store the average of the total number of nodes within a certain period after publication. This is because if the total number of nodes is different between the time when the total evaluation value of the published content is calculated and the current time, it is not known whether the total evaluation value is relatively high or low. By registering the total number of nodes at the time of calculation, it is possible to compensate for the difference in the total evaluation value due to the change in the total number of nodes.

  The total evaluation value of each content calculated as described above, the maximum value of the total evaluation value of each content, or the average value of the total evaluation value of each content is used to determine the ranking representing the popularity ranking of the content, This is used to determine the initial total evaluation value of pre-release content for which a total evaluation value has not yet been given (details will be described later).

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

  FIG. 4 is a diagram illustrating a schematic configuration example of the node Nn.

  As shown in FIG. 4, each node Nn includes a control unit 21 as a computer including a CPU having a calculation function, a working RAM, a ROM for storing various data and programs, and various data (for example, content data). Storage unit 22 composed of an HD (hard disk) or the like for storing and storing various programs and the like, and a buffer memory 23 for temporarily storing a replica of the received content data, etc. A decoder unit 24 for decoding (data expansion, decoding, etc.) encoded video data (video information) and audio data (audio information) included in a replica of the content data, and the decoded video data, etc. Video processing unit that performs predetermined drawing processing and outputs it as a video signal 5, a display unit 26 such as a CRT or a liquid crystal display for displaying video based on the video signal output from the video processing unit 25, and the decoded audio data into an analog audio signal D (Digital) / A (Analog) After the conversion, the audio processing unit 27 that amplifies this by an amplifier and outputs it, the speaker 28 that outputs the audio signal output from the audio processing unit 27 as a sound wave, and information between other nodes Nn and the like through the network 8 A communication unit 29 for performing communication control, an input unit 30 (for example, a keyboard, a mouse, or an operation panel) that receives an instruction from a user and gives 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 unit 30. They are 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 IP address and port number of a contact node that is an access destination when participating in the distributed content storage system S. 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 12 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, a content holding node, a content input node, and a content pre-holding node is performed.

  As described above, when the evaluation value request message is received from the total evaluation value management server MS, the control unit 21 evaluates the content ID corresponding to the replica stored in the storage unit 22 and the evaluation value indicating the evaluation value. A process of returning a response message to the total evaluation value management server MS is performed.

  Further, when the evaluation value request message is received, the control unit 21 checks the publication date and time of the content corresponding to the stored replica, and the publication date and time is within a predetermined period (for example, a certain period after publication). Only the contents may be configured to return an evaluation value response message indicating the evaluation value to the total evaluation value management server MS. As a result, for example, evaluation values are returned to the total evaluation value management server MS only for content within a certain period after publication, so that the load on the network 8 can be reduced. In addition, the total evaluation value management server MS can also update the total evaluation value for one aggregation only for contents within a certain period after publication, thereby reducing the load. The predetermined period may be set as a fixed value in each node Nn, or may be specified in an evaluation value request message from the total evaluation value management server MS.

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

(4-1. Calculation of total evaluation value)
First, the operation when the total evaluation value is calculated will be described with reference to FIG.

  FIG. 5A is a flowchart showing an evaluation value request process of the control unit 11 in the total evaluation value management server MS, and FIG. 5B shows a total evaluation value calculation process of the control unit 11 in the total evaluation value management server MS. FIG. 5C is a flowchart showing an evaluation value response process of the control unit 21 in the node Nn.

  In the total evaluation value management server MS, the process shown in FIG. 5A is repeatedly executed at regular intervals, for example, and is started when the time (for example, timer count-up) arrives. When the process is started, the control unit 11 first selects one of the nodes Nn, for example, at random from the plurality of nodes Nn registered in the node management table (step S1).

  Next, the control unit 11 uses the node information of the selected node Nn to connect to it, and transmits an evaluation value request message indicating a request for content evaluation value to the node Nn (step S2). .

  On the other hand, in the node Nn, the process shown in FIG. 5C is started when an evaluation value request message is received. When the processing is started, the control unit 21 lists contents corresponding to the replicas stored in the storage unit 22 of the own node (step S101). In this list-up, for example, the content IDs of all the contents registered in the evaluation value management table are stored in a predetermined area of the RAM. At this time, the control unit 21 may be configured to list only contents whose release date / time is within a predetermined period (for example, a certain period after release).

  Next, the control unit 21 selects one of the listed contents (step S102).

  Next, the control unit 21 acquires the evaluation value of the selected content from the evaluation value management table and describes it in the evaluation value list together with the content ID (step S103).

  Next, the control unit 21 determines whether or not the above processing has been completed for all the listed contents (step S104). If the above-described processing has not been completed for all the listed contents (step S104: NO), the control unit 21 returns to step S102 to select a content that has not yet been selected, and the same as above. Perform the process.

  On the other hand, when the above processing is completed for all the listed contents (step S104: YES), the control unit 21 evaluates including an evaluation value list in which the evaluation values and the like of the selected content are described. A value response message is returned to the total evaluation value management server MS (step S105), and the processing shown in FIG.

  Next, when the total evaluation value management server MS receives the evaluation value response message, the process shown in FIG. 5B is started. When the process is started, the control unit 11 lists all published contents (step S11).

  Note that, in the above-described step S101, if only the contents whose release date / time is within the predetermined period are listed, only the contents whose release date / time is within the predetermined period are listed here.

  In this list-up, for example, the content IDs of all the contents registered in the total evaluation value management table are stored in a predetermined area of the RAM.

  Next, the control unit 11 selects one of the listed contents (step S12).

  Next, the control unit 11 determines whether or not the evaluation value of the selected content is described in the evaluation value list included in the evaluation value response message (step S13), and is described in the evaluation value list. If yes (step S13: YES), the process proceeds to step S14. If not described in the evaluation value list (step S13: NO), the process proceeds to step S15.

  In step S14, the control unit 11 acquires the evaluation value of the selected content from the evaluation value list. On the other hand, in step S15, the control unit 11 sets the evaluation value of the selected content to “0” instead of acquiring it from the evaluation value list.

  Next, the control unit 11 acquires the latest total evaluation value of the selected content from the total evaluation value management table (step S16).

  Next, the control unit 11 is based on the content evaluation value acquired in step S14 (or the content evaluation value set to “0” in step S15) and the latest total evaluation value of the content acquired in step S16. For example, a new total evaluation value is calculated by the above-described arithmetic expression (2) (step S17).

  Next, the control unit 11 updates (overwrites) the latest total evaluation value registered in the total evaluation value management table with the total evaluation value of the newly calculated content (step S18).

  Further, the control unit 11 newly registers (registers in the evaluation value calculation history information) the total evaluation value of the newly calculated content and the total number of nodes at the time of the calculation (the average of the total evaluation values is calculated). If it is calculated by the above equation (4), this process is unnecessary).

  Next, the control unit 11 acquires the maximum value of the total evaluation value of the selected content from the total evaluation value management table (step S19).

  Next, the control unit 11 compares the new total evaluation value calculated in step S17 with the maximum value of the total evaluation values acquired so far in step S19, and determines the larger one as the maximum value of the total evaluation value. (Step S20).

  Next, the control unit 11 updates (overwrites) the determined maximum value of the total evaluation value, the maximum value of the total evaluation value registered in the total evaluation value management table based on the current total number of nodes, and the total number of nodes at the time of the calculation. (Step S21).

  Next, the control unit 11 determines whether or not the above processing has been completed for all the listed contents (step S22). If the above-described processing has not been completed for all the listed contents (step S22: NO), the control unit 21 returns to step S12 to select a content that has not yet been selected and the same as above. Perform the process.

  On the other hand, when the above process for all the listed contents is completed (step S22: YES), the control unit 11 ends the process shown in FIG.

  In addition, between the said step S18 and S19, you may comprise the control part 11 so that the average value of each total evaluation value registered within the predetermined period (for example, fixed period after disclosure) may be calculated. In this case, the control unit 11 acquires each total evaluation value registered within a predetermined period (for example, a certain period after the release) of the content from the total evaluation value management table (evaluation value calculation history information), and The average value is calculated by, for example, the calculation formula (3) or the calculation formula (4) and registered in the total evaluation value management table, for example. In this case, the target listed in step S11 may be content whose publication date and time is within a predetermined period (for example, a certain period after publication).

  According to the calculation method of the total evaluation value described above, even if the number of nodes Nn increases, the total evaluation value of the published content can be obtained quickly and accurately without taking much time and cost for the investigation (that is, actually As a value close to the total evaluation value). In addition, not only the current total evaluation value of each content, but also the maximum total evaluation value from the release to the present, and the average value of the total evaluation value within a predetermined period after the release, the content from various viewpoints Can be evaluated.

(4-2. Determination of ranking)
Next, with reference to FIG. 6, the operation when the ranking representing the popularity ranking of content is determined will be described. In this ranking determination, a ranking representing the popularity ranking of content is determined based on the total evaluation value of each content.

  FIG. 6 is a flowchart showing the ranking determination process of the control unit 11 in the total evaluation value management server MS.

  In the total evaluation value management server MS, the process shown in FIG. 6 is started by a ranking determination request from a terminal used more by a system administrator or the like, for example. When the process is started, the control unit 11 first acquires the latest total evaluation value of all the target contents from the information regarding the latest total evaluation value in the total evaluation value management table (step S31). Note that a maximum value or an average value of the total evaluation values may be acquired instead of the latest total evaluation value.

  Next, the control unit 11 sorts the latest total evaluation values of each acquired content in ascending order, that is, determines the ranking representing the popularity ranking of the content by arranging in descending order of the total evaluation value (step S32), and stores the data of the ranking To do. In addition, instead of the latest total evaluation value, it may be configured to be sorted in ascending order of the maximum value or the average value of the total evaluation values.

  Next, the control unit 11 returns data indicating the stored ranking to the requested terminal (step S33), and ends the process.

  According to the ranking determination method described above, by using the latest total evaluation value of published content, the maximum value of the total evaluation value, or the average value of the total evaluation value, the ranking representing the popularity ranking of the content can be determined efficiently. Can do. For example, if the latest total evaluation value of each content is sorted in ascending order, the content ranking can be obtained in descending order of the current total evaluation value, and the maximum total evaluation value of each content is sorted in ascending order. Can obtain the ranking of the contents in the order of the highest evaluation value in the past, and when the average value of the total evaluation values of each content is sorted in ascending order, the average of the total evaluation values within a predetermined period is the highest evaluation value. The ranking of contents can be obtained in descending order.

(4-3. Determination of initial total evaluation value of pre-release content)
Next, the operation when the initial total evaluation value of the pre-release content is determined will be described separately for the first embodiment and the second embodiment. In the determination of the initial total evaluation value of the pre-release content, based on the total evaluation value of the published content that has at least one keyword of the pre-release content that is not given the total evaluation value and is given the total evaluation value, An initial total evaluation value of the pre-release content is determined.

  As a premise for determining the initial total evaluation value of such pre-release content, a keyword is assigned to each content handled by the content distributed storage system S, and the keyword assigned to each content is: For example, it is registered and managed in the keyword management database in association with the content ID. As such a keyword, for example, a keyword that is generally given to search for content can be used, and the number of the keyword is arbitrary. For example, in the case of movie content, keywords such as movie title, genre name, lead name, and director name are given, and in the case of music content, music title, genre name, artist name, songwriter name, and composition A keyword such as a person's name is given. The keyword management database may be provided in the total evaluation value management server MS, or may be provided in another server to which the total evaluation value management server MS can be connected.

(4-3-1. Example 1)
First, the operation of the first embodiment will be described with reference to FIGS.

  FIG. 7 is a flowchart illustrating the initial total evaluation value determination process of the control unit 11 in the total evaluation value management server MS in the first embodiment. FIG. 8 is a diagram illustrating how the initial total evaluation value of the pre-release content is determined in the first embodiment.

  In the total evaluation value management server MS, the process shown in FIG. 7 is started by, for example, an initial total evaluation value determination request for content before publication from a terminal used by a system administrator or the like. When the processing is started, the control unit 11 first specifies pre-release content (content not given a total evaluation value) related to the request (step S41).

  Next, the control unit 11 acquires the specified keyword (s) of the pre-release content from the keyword management database (step S42). For example, the keywords of the pre-release content are A and D.

  Next, the control unit 11 selects one of the acquired keywords (for example, randomly or in the order of registration) (step S43).

  Next, the control unit 11 refers to the keyword management database and specifies a plurality of published contents having the selected keyword (step S44).

  Next, the control unit 11 acquires the latest total evaluation value of each identified published content from information regarding the latest total evaluation value in the total evaluation value management table, and acquires all keywords of each content from the keyword management database ( Step S45). Note that a maximum value or an average value of the total evaluation values may be acquired instead of the latest total evaluation value.

  Next, the control unit 11 determines an evaluation value of the keyword of the content based on the identified total evaluation value of each content (step S46). Instead of the latest total evaluation value, the evaluation value of the keyword of the content may be determined based on the maximum value or the average value of the total evaluation value.

  For example, in the example of FIG. 8, since the total evaluation value of the content 1 having the selected keyword A is “90”, the total evaluation value is determined as it is as the evaluation value of the keyword A. On the other hand, since the total evaluation value of the content 3 having the selected keyword A is “60”, the total evaluation value is determined as it is as the evaluation value of the keyword A.

  Next, the control unit 11 calculates an average value of the evaluation values of the keywords for which the evaluation values are determined across a plurality of contents (step S47).

  For example, in the example of FIG. 8, the average value of the evaluation values of the keyword A is determined across the contents 1 and 3.

  Next, the control unit 11 determines whether or not all the keywords acquired in step S42 have been processed (step S48). If not processed (step S48: NO), the control unit 11 returns to step S43 and is still not yet processed. A keyword that has not been selected is selected, and the same processing as described above is performed.

  For example, in the example of FIG. 8, since the total evaluation value of the content 2 having the selected keyword D is “40”, the total evaluation value is determined as it is as the evaluation value of the keyword D. On the other hand, since the total evaluation value of the content 3 having the selected keyword D is “60”, the total evaluation value is determined as it is as the evaluation value of the keyword D. Then, the average value of the evaluation values of the keyword D is determined across the contents 2 and 3.

  If it is determined in step S48 that all the keywords have been processed (step S48: YES), the maximum value among the average values of the evaluation values calculated for each of the plurality of keywords of the pre-release content. Is determined as the initial total evaluation value of the pre-release content (step S49).

  For example, in the example of FIG. 8, the average value of the evaluation values of the larger keyword A among the average value of the evaluation values of the keyword A and the evaluation value of the keyword D is the initial total evaluation value of the pre-release content. As determined.

  Next, the control unit 11 registers the determined initial total evaluation value of the pre-release content in the total evaluation value management table in association with information such as the content ID of the pre-release content (step S50).

  Next, the control unit 11 returns data indicating the determined initial total evaluation value of the pre-release content to the requested terminal (step S51), and ends the process.

  Note that a value obtained by further averaging the average values of the evaluation values calculated for each of the plurality of keywords of the pre-release content may be determined as the initial total evaluation value of the pre-release content.

(4-3-2. Example 2)
Next, with reference to FIG. 9 and FIG. 10, the evaluation value calculation processing of content before publication in the second embodiment will be described.

  FIG. 9 is a flowchart illustrating the initial total evaluation value determination process of the control unit 11 in the total evaluation value management server MS in the second embodiment. FIG. 10 is a diagram illustrating how the initial total evaluation value of the pre-release content is determined in the second embodiment.

  In the total evaluation value management server MS, the process shown in FIG. 9 is started by a request for determining an initial total evaluation value of pre-release content from a terminal used by a system administrator or the like, for example. When the process is started, the control unit 11 first specifies pre-release content (content that is not given a total evaluation value) related to the request (step S71).

  Next, the control unit 11 acquires all keywords (plural) from the keyword management database (step S72).

  Next, the control unit 11 determines whether or not the process is the first execution (step S73). If the process is the first execution (step S73: YES), “1” is set to the evaluation values of all keywords. (Step S74). On the other hand, when it is not the first execution (step S73: NO), the control unit 11 acquires the evaluation values of all keywords from the keyword management database (step S75).

  Next, the control unit 11 identifies all published contents (step S76), and acquires the latest total evaluation value of each identified published content from the information regarding the latest total evaluation value in the total evaluation value management table (step S76). S77). Note that a maximum value or an average value of the total evaluation values may be acquired instead of the latest total evaluation value.

  Next, the control unit 11 selects one identified published content (step S78).

  Next, the control unit 11 selects all the keywords included in the selected content (step S79).

  Next, the control unit 11 uses the evaluation value of each selected keyword as a weight, distributes the total evaluation value of the selected content to each keyword (step S80), and determines the evaluation value of each keyword. Instead of the latest total evaluation value, the evaluation value of the keyword of the content may be determined based on the maximum value or the average value of the total evaluation value.

  For example, in the example of FIG. 10A, the total evaluation value of the content 1 is “90”, and the evaluation values of each keyword are all set to “1” in step S74. The total evaluation value “90” of the content 1 is divided into three equal parts, and “30” is distributed to the keywords A, B, and C to determine the evaluation value.

  Next, the control unit 11 determines whether or not all the specified contents have been processed (step S81), and if not processed (step S81: NO), the control unit 11 returns to step S78 and is still selected. The content that does not exist is selected and the same processing as described above is performed. In this way, for example, as shown in FIG. 10A, the keyword evaluation values are determined for the contents 2 and 3 as well.

  If it is determined in step S81 that all contents have been processed (step S81: YES), the control unit 11 selects one keyword (step S82).

  Next, the control unit 11 calculates the average value of the evaluation values of the selected keywords across a plurality of contents (step S83).

  For example, in the example of FIG. 10A, the average evaluation value of the keyword A is determined across the contents 1 and 3.

  Next, the control unit 11 determines whether or not all the keywords acquired in step S72 have been processed (step S84). If not processed (step S84: NO), the control unit 11 returns to step S82 and is still not yet processed. A keyword that has not been selected is selected, and the same processing as described above is performed. In this way, for example, as shown in FIG. 10A, average values are also calculated for the keywords B, C, and D.

  If it is determined in step S84 that all the keywords have been processed (step S84: YES), the control unit 11 determines whether or not a preset termination criterion is satisfied (step S84). S85) If the end criterion is not satisfied (step S85: NO), the process returns to step S78 and the same processing as described above is performed.

  For example, in the case of the content 2 shown in FIG. 10B, the average values “25” and “20” of the evaluation values of the keywords B and D calculated in the immediately preceding step S83 are weighted, and the content The total evaluation value “40” of 2 is distributed to the keywords B and D according to the weight, and the evaluation value is determined.

  In this way, the processing of step S78 to step S85 is repeatedly looped until the end determination criterion is satisfied. In such an iterative loop, the control unit 11 assigns the average evaluation value of the keyword calculated in the immediately preceding step S83 as a weight, and further distributes the total evaluation value of the content to the keyword of the content, so that the keyword of the content The evaluation value of the content is determined (that is, updated from the previous evaluation value) and further distributed (ie, updated), and the keyword evaluation value of the content is converted into a plurality of contents for each keyword. The average value of the final evaluation value of the keyword is calculated by repeating the process of calculating the average value of the evaluation value of the keyword over a predetermined number of times.

  By the way, the type and threshold value of the end determination criterion can be arbitrarily selected by the user. For example, it is determined whether or not the difference between the evaluation values of the keyword before and after the update is equal to or less than tens to several hundreds (for example, 100) of the average evaluation value of the keyword. It is said. Alternatively, it is determined whether or not the processing of step S78 to step S85 has been looped for a preset number of times (for example, 100 times). Alternatively, it is determined whether or not the processing in steps S78 to S85 has been repeatedly performed for a preset time (for example, 3 minutes).

  Thus, when the end criterion is satisfied (step S85: YES), the control unit 11 adds the average value of the final evaluation values calculated as described above for each of the plurality of keywords of the pre-release content. Then, this added value is determined as the initial total evaluation value of the pre-release content (step S86).

  Next, the control unit 11 registers the determined initial total evaluation value of the pre-release content in the total evaluation value management table in association with information such as the content ID of the pre-release content, and the evaluation values of all keywords. (The average value of the final keyword evaluation values described above) is registered in the keyword management database (step S87). Thus, as described above, the evaluation values of all registered keywords are acquired in step S75 and used as weights in step S80.

  Next, the control unit 11 returns data indicating the determined initial total evaluation value of the pre-release content to the requested terminal (step S88), and ends the process.

  According to the method for determining the initial total evaluation value of the pre-release content described above (Example 1 or Example 2), the latest total evaluation value of the published content, the maximum value of the total evaluation value, or the average value of the total evaluation value is used. As a result, it is possible to predict (estimate) the popularity of pre-release content relatively easily, without requiring the system administrator to spend time, and to distribute and store an appropriate number of replicas in the system in advance. be able to.

  Therefore, it can be avoided that the number of replicas to be distributed and stored in advance in the system S is too small, and access can be prevented from concentrating on the replica after the content is published. Therefore, even if replica download requests to the content holding node are frequently issued, stable content distribution is possible. Moreover, it can be avoided that the number of the replicas is too large, and the storage area for storing the replicas in each node Nn is wasted, so that the storage area can be prevented from being compressed. Thereby, an increase in network load can be prevented.

(4-4. Calculation of total evaluation value when content replica is divided and stored)
In the content distributed storage system S described above, each cache (divided replicated data) obtained by dividing one content replica into a plurality of pieces may be distributed and stored in a plurality of nodes Nn. In such a case, a certain node Nn does not always store all the caches that constitute a certain replica, but may store only a part of the cache that constitutes the replica. Each cache is given an evaluation value indicating the evaluation of the content corresponding to the cache (that is, the content having the cache as a component), and the evaluation value is stored in the cache. Each node Nn is registered and managed in the above-described evaluation value management table. The evaluation value is associated with the serial number of each cache (for example, indicating the data position in the cache replica).

  In such a content distributed storage system S, the most accurate method is to investigate the total evaluation value for each cache and use the average of these as the total evaluation value of the content. However, in this case, the content holding node that stores the cache must transmit evaluation values for the number of caches to the total evaluation value management server MS, and therefore the amount of data that must be transmitted when the number of divisions increases. Increasing and system addition will increase. Therefore, in this case, the content holding node does not transmit the evaluation value for each cache, but the average value of the evaluation values assigned to each cache stored in the own node among all the caches constituting a certain content. Is transmitted to the total evaluation value management server MS as the evaluation value of the content.

  Hereinafter, the operation when the divided cache is stored in the node Nn will be described with reference to FIG.

  FIG. 11 is a flowchart showing the evaluation value response process of the control unit 21 in the node Nn considering the case where the divided cache is stored, which replaces the process of FIG. 5C described above. In addition, the process of the control part 11 in the total evaluation value management server MS in this case is the same as the process of FIG. 5 (A) and FIG. 5 (B).

  In the node Nn, the process shown in FIG. 11 is started when an evaluation value request message from the total evaluation value management server MS is received. When the processing is started, the control unit 21 lists the contents corresponding to the replicas or caches stored in the storage unit 22 of its own node, similarly to step S101 shown in FIG. 5C (step S201). ).

  Next, the control unit 21 selects one of the listed contents (step S202).

  Next, the control unit 21 determines whether or not the selected content is divided (step S203). When the selected content is not divided (step S203: NO), the control unit 21 proceeds to step S204 and is divided. (Step S203: YES), the process proceeds to Step S205.

  In step S204, the control unit 21 acquires the evaluation value of the selected content from the evaluation value management table, describes it in the evaluation value list together with the content ID, and proceeds to step S211.

  On the other hand, in step S205, the control unit 21 lists the caches stored in the storage unit 22 of the own node among the caches of the selected content. In this list-up, for example, the serial number of the cache is stored in a predetermined area of the RAM.

  Next, the control unit 21 selects one from the caches listed above (step S206).

  Next, the control unit 21 acquires the evaluation value assigned to the selected cache from the evaluation value management table (step S207).

  Next, the control unit 21 determines whether or not the processing for all the listed caches has been completed (step S208). If the above processing has not been completed for all the caches listed above (step S208: NO), the control unit 21 returns to step S206 to select a cache that has not been selected, and the same as above. Perform the process.

  On the other hand, when the processing for all the listed caches is completed (step S208: YES), the control unit 21 calculates the average value of the evaluation values assigned to the respective caches and calculates the average value. Is determined as the evaluation value of the content (step S209).

  FIG. 12 is a conceptual diagram showing how the average value of evaluation values assigned to each cache is determined as the content evaluation value. The node N1 shown in FIG. 12 stores some of the caches X1, X3, and X5 among all the caches X1 to X6 that constitute the content X (replica), and the caches X1, X3, and X5 store the caches X1, X3, and X5. An average value (30 = (30 + 25 + 35) / 3) of the assigned evaluation values is determined as the evaluation value of the content X.

  Next, the control unit 21 describes the evaluation value of the content obtained as the average value together with the content ID in the evaluation value list (step S210), and proceeds to step S211.

  In step S211, the control unit 21 determines whether or not the above processing has been completed for all the contents listed in step S201. If the above processing for all the listed contents has not been completed (step S211: NO), the control unit 21 returns to step S202 to select a content that has not yet been selected, and the same as above. Perform the process.

  On the other hand, when the above processing for all the listed contents is completed (step S211: YES), the control unit 21 sends an evaluation value response message including an evaluation value list in which the evaluation values of the content are described. Is returned to the total evaluation value management server MS (step S212), and the processing shown in FIG.

  Then, in the total evaluation value management server MS, the process shown in FIG. 5B is performed to calculate the total evaluation value of the content, and the processes shown in FIGS. 6, 7, and 9 are executed in the same manner as described above. It will be.

  According to the method for calculating the total evaluation value in the case where the replica of the content described above is divided and stored, the total evaluation value of the published content can be quickly obtained without increasing the system load even if the number of divided caches increases. In addition, it can be obtained with high accuracy.

  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 the total evaluation value management server MS. It is a figure which shows an example of the information registered into the total evaluation value management table. It is a figure which shows the example of an outline structure of the node Nn. (A) is a flowchart showing the evaluation value request processing of the control unit 11 in the total evaluation value management server MS, (B) is a flowchart showing the total evaluation value calculation processing of the control unit 11 in the total evaluation value management server MS, (C) is a flowchart showing an evaluation value response process of the control unit 21 in the node Nn. It is a flowchart which shows the ranking determination process of the control part 11 in the total evaluation value management server MS. In Example 1, it is a flowchart which shows the initial total evaluation value determination process of the control part 11 in the total evaluation value management server MS. In Example 1, it is a figure which shows a mode until the initial total evaluation value of the content before a publication is determined. In Example 2, it is a flowchart which shows the initial total evaluation value determination process of the control part 11 in the total evaluation value management server MS. In Example 2, it is a figure which shows a mode until the initial total evaluation value of the content before a publication is determined. It is a flowchart which shows the evaluation value response process of the control part 21 in the node Nn considering the case where the divided | segmented cache is preserve | saved. It is a conceptual diagram which shows a mode that the average value of the evaluation value provided to each cache is determined as an evaluation value of content.

Explanation of symbols

8 Network 9 Overlay Network 11 Control Unit 12 Storage Unit 13 Communication Unit 14 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 MS Total evaluation value management server Nn node S Content distributed storage system

Claims (13)

A distributed content storage system configured by participation of a plurality of node devices connected to a network, wherein each of the node devices in which duplicate data of a plurality of contents is distributed and stored in a plurality of node devices, and the duplicate data is stored A total evaluation value management device that manages, for each content, a total evaluation value that represents the sum of the evaluation values in the content distributed storage system in which an evaluation value that represents the evaluation of the content is managed by
Total evaluation value storage means for storing a total evaluation value of each of the contents;
Node device selection means for selecting any one of the plurality of node devices participating in the content distributed storage system;
Request information transmitting means for transmitting request information indicating a request for the evaluation value of the content to the selected node device;
Evaluation value information receiving means for receiving, from the node device, evaluation value information indicating an evaluation value of content corresponding to the duplicate data stored in the node device that has received the request information;
Total evaluation value acquisition means for acquiring the total evaluation value of the content indicated in the received evaluation value information from the total evaluation value storage means;
A total evaluation value calculating means for calculating a new total evaluation value based on the total evaluation value of the acquired content and the evaluation value of the content indicated in the received evaluation value information;
Total evaluation value update means for updating the total evaluation value of the previous content stored in the total evaluation value storage means with the total evaluation value of the newly calculated content;
A total evaluation value management device comprising: In the total evaluation value management apparatus according to claim 1,
The total evaluation value calculating means includes
An evaluation value obtained by dividing the total evaluation value of the acquired content by the total number of node devices participating in the content distributed storage system, and a number obtained by subtracting the number of node devices that transmitted the evaluation value information from the total number, Multiply
A total evaluation value management device that calculates the new total evaluation value by adding the multiplied value and the evaluation value of the content indicated in the received evaluation value information. In the total evaluation value management apparatus according to claim 1 or 2,
The total evaluation value management device, wherein the node device selection means randomly selects one of the plurality of node devices participating in the content distributed storage system. In the total evaluation value management device according to any one of claims 1 to 3,
A series of processing by the node device selection unit, the request information transmission unit, the evaluation value information reception unit, the total evaluation value acquisition unit, the total evaluation value calculation unit, and the total evaluation value update unit is repeatedly executed at predetermined time intervals. The total evaluation value management device characterized by being performed. In the total evaluation value management apparatus as described in any one of Claims 1 thru | or 4,
When the total evaluation value of the new content is calculated by the total evaluation value calculating means, the total evaluation value of the new content is compared with the total evaluation value of the previous content, and the larger one is obtained as the maximum value of the total evaluation value. A total evaluation value management apparatus, further comprising evaluation maximum value calculation means. In the total evaluation value management apparatus according to any one of claims 1 to 5,
Each time the total evaluation value of the new content is calculated by the total evaluation value calculating means, the total evaluation value is stored separately, and the average of the total evaluation values for the specific content stored in the predetermined period is stored. A total evaluation value management device further comprising total evaluation average value calculation means for calculating a value. In the total evaluation value management device according to any one of claims 1 to 6,
The apparatus further comprises ranking determining means for determining a ranking representing the popularity ranking of the content based on the total evaluation value of each content, the maximum value of the total evaluation value of each content, or the average value of the total evaluation values of each content. Total evaluation value management device. In the total evaluation value management apparatus as described in any one of Claims 1 thru | or 7,
A content specifying unit that has at least one content keyword that is not given the total evaluation value and that specifies the content that is given the total evaluation value;
The total evaluation value calculating unit is configured to calculate a total evaluation value of content to which the total evaluation value is not given based on the total evaluation value of the identified content. In the content distributed storage system, divided copy data obtained by dividing copy data of one content into a plurality of pieces is distributed and stored in the plurality of node devices, and each of the node devices storing the divided copy data stores the divided data. An evaluation value representing the evaluation of content having duplicate data is assigned to the divided duplicate data and managed.
The evaluation value information receiving means, when the divided copy data stored in the node device that has received the request information is a part of all the divided copy data constituting the content corresponding thereto, 9. The evaluation value information indicating an average value of evaluation values assigned to the partial divided copy data as an evaluation value of the content is received from the node device. The total evaluation value management device according to one item. A node device that has received the request information transmitted from the total evaluation value management device according to claim 9,
A node device characterized by transmitting evaluation value information indicating an average value of evaluation values assigned to the partial divided duplicate data as an evaluation value of the content to the total evaluation value management device.   A management processing program for causing a computer to function as the total evaluation value management apparatus according to any one of claims 1 to 9. A distributed content storage system configured by participation of a plurality of node devices connected to a network, wherein each of the node devices in which duplicate data of a plurality of contents is distributed and stored in a plurality of node devices, and the duplicate data is stored In the distributed content storage system in which the evaluation value representing the evaluation of the content is managed by
A total evaluation value management device that manages a total evaluation value representing the total sum of the evaluation values for each content,
Total evaluation value storage means for storing a total evaluation value of each of the contents;
Node device selection means for selecting any one of the plurality of node devices participating in the content distributed storage system;
Request information transmitting means for transmitting request information indicating a request for the evaluation value of the content to the selected node device;
Evaluation value information receiving means for receiving, from the node device, evaluation value information indicating an evaluation value of content corresponding to the duplicate data stored in the node device that has received the request information;
Total evaluation value acquisition means for acquiring the total evaluation value of the content indicated in the received evaluation value information from the total evaluation value storage means;
A total evaluation value calculating means for calculating a new total evaluation value based on the total evaluation value of the acquired content and the evaluation value of the content indicated in the received evaluation value information;
Total evaluation value update means for updating the total evaluation value of the previous content stored in the total evaluation value storage means with the total evaluation value of the newly calculated content;
A content distributed storage system comprising: A distributed content storage system configured by participation of a plurality of node devices connected to a network, wherein each of the node devices in which duplicate data of a plurality of contents is distributed and stored in a plurality of node devices, and the duplicate data is stored A content total evaluation value management method in a distributed content storage system in which an evaluation value representing an evaluation of the content is managed by:
A total evaluation value management device that manages a total evaluation value representing the total sum of the evaluation values for each content,
Storing a total evaluation value of each of the contents;
Selecting any one of the plurality of node devices participating in the distributed content storage system;
Transmitting request information indicating a request for an evaluation value of the content to the selected node device;
Receiving the evaluation value information indicating the evaluation value of the content corresponding to the copy data stored in the node device that has received the request information from the node device;
Obtaining a total evaluation value of the content indicated in the received evaluation value information from the total evaluation value storage means;
Calculating a new total evaluation value based on the total evaluation value of the acquired content and the evaluation value of the content indicated in the received evaluation value information;
Updating the previous total content evaluation value stored in the total evaluation value storage means with the newly calculated total content evaluation value;
A total evaluation value management method comprising:

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