JP2010108279A - Content distribution method and system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a content distribution method and system for achieving content distribution with small delay. <P>SOLUTION: The content distribution system includes: a logical expression conversion part 102 for converting retrieval conditions configured of the logical product and logical sum of context into a multinomial logical expression in which a plurality of logical product terms are bundled by the logical sum; a transmission part 103 for transmitting a retrieval request message for requesting the retrieval of a content receiver who registers the context for each context; a reception part 104 for receiving a retrieval response message returned in response to each retrieval request message, and recorded with the content receiver who registers each content; a distribution destination specification part 105 for specifying the content receiver who registers the context satisfying each logical product term of the multinomial logical expression based on the received retrieval response message; and a content distribution part 106 for distributing the content to the specified content receiver. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a content distribution method and system for distributing content via a network, and more particularly to a content distribution method and system suitable for a peer-to-peer (P2P) network.

  In the conventional content distribution method in P2P, as disclosed in Non-Patent Document 1 and Patent Document 1, a plurality of content distribution peer nodes and content reception peer nodes constitute a P2P network. A context is registered by the content receiver in the content receiving peer node. In the content distribution peer node, a context search condition for selecting a content distribution destination by the content distributor is registered.

  The context is a search parameter used for the content receiver to narrow down the content desired to be distributed, and the content sender to narrow down the distribution destination of the content, and includes context items and context values. The context item is, for example, the content type desired by the content receiver, the installation location of the receiving node, the desired reception time of the content, the communication means to be used, gender, age, hobby preference, occupation type, family information, etc. Is a specific value of the context item. For example, when the content type desired to be received is used as the context item, it indicates the type of content such as “sports”, “travel”, and “music”. Value or sign.

  When the content receiver transmits a message in which its context is recorded from the content receiving peer node, the context value in each context item is registered in one peer node determined according to the context value.

  On the other hand, the content distributor transmits a plurality of context search request messages from the content distribution peer node to the peer node determined according to each context value of the search condition. The peer node that has received the context search request message returns a search response message in which content recipients that match the search conditions are recorded.

After receiving the corresponding plurality of context search response messages, the content distributor creates a list of content recipients having contexts that match the search conditions by a logical operation on the acquired content recipient list, and includes the list in this list. Distribute content only to the content recipients.
Kanno, Nakamura, “Push-type P2P Information Distribution Platform”, 2007 IEICE General Conference, B-19-20, p.582, March 7, 2007. JP 2008-158931 A

For example, when a content distributor wants to search for a content recipient whose context value in context item A is a0 or a1 and whose context value in context item B is b0 or b1, logic that represents the context search condition The formula becomes the following formula (1)

(a0 OR a1) AND (b0 OR b1)… (1)

  After receiving all context search response messages, the content distributor starts a logical operation to obtain a list of content recipients having contexts that match the search conditions. For this reason, when the four search request messages having the context values a0, a1, b0, and b1 are transmitted, it is not possible to specify the content distribution destination until all four search response messages for the four request messages are received. Therefore, even when only one search response message is delayed, there is a technical problem that the delay is spread to the content distribution to all content recipients.

  An object of the present invention is to provide a content distribution method and system that solves the above-described problems of the prior art and enables content distribution with little delay.

  In order to achieve the above object, the present invention provides a content distribution system in which a content receiver registers its own context in advance, and the content distributor distributes content to content receivers that match the context search conditions. It is characterized in that such measures are taken.

  (1) A logical expression conversion means for converting a search condition composed of logical product and logical sum of contexts into a multiple logical expression in which a plurality of logical product terms are concatenated with logical sum, and register the context for each context. Means for transmitting a search request message for requesting a search for a content receiver, and means for receiving a search response message that is replied to each search request message and recorded by a content receiver that registers each context And means for specifying a content receiver whose registered context satisfies each logical product term of the polynomial formula based on the received search response message, and content for distributing the content to the specified content receiver And a distribution means.

  (2) The content distribution means distributes the content only to the content recipient newly specified based on the search response message newly received by the means for specifying the content recipient.

  According to the present invention, the following effects are achieved.

  (1) Satisfy the search conditions based on some search response messages even before the reception of the search response message for the search request message is completed and all content recipients that satisfy the search conditions are identified. If there is a content recipient that has been found to be able to be delivered, the content delivery can be started in order from the content recipient. Therefore, even if a delay occurs in a part of the search response message, the delay does not affect all the content delivery. Furthermore, since content distribution is started in order from content receivers that are found to satisfy the search conditions, it is possible to distribute content faster than before.

  (2) Even if a content recipient who satisfies the search conditions is newly found based on the newly received search response message, the content will not be delivered if content delivery to the content recipient has already ended. Duplicate transmission of content is prevented.

  Hereinafter, the best embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration of a P2P network to which the content distribution system of the present invention is applied, and includes at least one content distribution peer node N and peer nodes of a plurality of content recipients (X0, X1, X2, X3). And a plurality of context management peer nodes A0, A1, B0, B1 that manage the context of the content recipient are connected via a network. In order to simplify the explanation, each peer node is described as being specialized for any one of a content distribution peer node, a content recipient peer node, and a context management peer node. However, each peer node has a plurality of functions. You may have.

  FIG. 2 is a diagram schematically showing the contents of the context registered by each content recipient X0, X1, X2, X3. For the content recipient X0, two context values “a0” for the context item A are shown. ”And“ a1 ”are registered, and one context value“ b0 ”is registered for the context item B. Similarly, for the content recipient X1, one context value “a0” is registered for the context item A, and two context values “b0” and “b1” are registered for the context item B. When a plurality of context values are registered in one context item, the search condition is satisfied if any one of them matches. Therefore, if the content recipient is X0, it means that the user wants to receive content whose search condition is [a0 AND b0] or [a1 AND b0].

  When context management peer nodes A0, A1, B0, B1 have a distributed hash table (DHT) and each content recipient X0, X1, X2, X3 sends a registration message in which their context is recorded from their peer node, As shown in FIG. 3, the hash value of each context value is stored in the distributed hash table of each context management peer node A0, A1, B0, B1 according to the node ID (here, A0, A1, B0, or B1). Correspondence with the content receiver is registered.

  FIG. 4 is a functional block diagram showing a configuration of an embodiment of the content distribution peer node N, where a configuration unnecessary for the description of the present invention is omitted.

  The search condition input unit 101 receives a search condition configured by logical product and logical sum of context values as a search condition for the content distributor to select content recipients. Here, the description will be continued assuming that the logical expression of the above expression (1) is input as a search condition. The logical expression conversion unit 102 converts the logical expression of the input search condition into a multinomial logical expression in which a plurality of logical product terms are bundled with a logical sum.

In the present embodiment, the logical expression of the above expression (1) is converted into a polynomial logical expression of the following expression (2). That is, the logical product of two logical sum terms (a0 OR a1) and (b0 OR b1) is four logical product terms (a0 AND b0), (a0 AND b1), (a1 AND b0), (a1 AND b1 ). In this multinomial logical expression, the content receiver Xn whose context value satisfies one of the four logical product terms satisfies the search condition of the above expression (1).

(a0 AND b0) OR (a0 AND b1) OR (a1 AND b0) OR (a1 AND b1)… (2)

  The request message sending unit 103 requests, for each of the context values a0, a1, b0, b1 included in the above formula (2), four search request messages REQ (a0 ), REQ (a1), REQ (b0), and REQ (b1) are transmitted to the corresponding context management peer nodes A0, A1, B0, and B1 via the I / F 108, respectively. The response message receiving unit 104 receives the search response messages REP (a0), REP (a1), REP (b0), and REP (b1) returned from the peer nodes A0, A1, B0, and B1 via the I / F 108. . In each search response message REP, the content recipient (identifier) that registers the corresponding context is recorded.

  Each time the distribution destination specifying unit 105 receives the search response message REP, the distribution destination specifying unit 105 determines whether there is a content receiver that can be specified only by the received search response message REP. That is, in this embodiment, if the content receiver who registers the context value “a0” and the content receiver that registers the context value “b0” are found, the content receiver X1 is expressed by the above equation (2). It can be determined that the first term (a0 AND b0) is satisfied. Therefore, as long as the response messages REP (a0) and REP (b0) can be received, the content receiver X1 can be identified as the delivery destination even before receiving other response messages REP (a1) and REP (b1). The content distribution unit 106 extracts content from the database 107 and distributes it every time a content recipient as a distribution destination is specified.

  FIG. 5 is a flowchart showing the operation of the content distribution peer node N, and FIG. 6 is a sequence flow showing a communication procedure between the content distribution peer node and other peer nodes.

  When a logical expression of a search condition is input to the search condition input unit 101 in step S1, in step S2, this logical expression is a multiple logical expression in which a plurality of logical product terms are bundled with a logical sum in the logical expression conversion unit 102. Is converted to In the present embodiment, the logical expression of the above equation (1) is input and converted into a multinomial logical expression of the above equation (2).

  In step S3, the request message transmitting unit 103 requests a search for a peer node that registers a message REQ (a0) for registering a context value “a1” and a message REQ (a0) for registering a context value “a1”. Message REQ (a1), message REQ (b0) requesting the search for the peer node registering the context value “b0”, and message REQ (b1) requesting the search for the peer node registering the context value “b1” Generated and transmitted to the corresponding context management peer nodes A0, A1, B0, and B1, respectively.

  At time t1 in FIG. 6, the search response message REP (a0) corresponding to the context value “a0” is received by the response message receiving unit 104. When this is detected in step S4, the process proceeds to step S5. In step S <b> 5, the distribution destination specifying unit 105 determines whether there is a content receiver that can be specified only by the received response message. Here, since none of the four logical product terms of the above formula (2) can be satisfied, the process returns to step S4.

  Next, the search response message REP (b1) corresponding to the context value “b1” is received at time t2 in FIG. 6, and when this is detected in step S4, the process proceeds to step S5. Here, in addition to the content recipients who have registered the context value “a0”, the content recipients who have newly registered the context value “b1” are clarified. As a result, the second of the above equation (2) Since the content receiver X1 satisfying the logical product term (a0 AND b1) of the terms is specified as the delivery destination, the process proceeds to step S6.

  In step S6, the content is distributed from the content distribution unit 106 to the peer node of the content recipient X1. In step S7, it is determined whether or not reception of all the search response messages REP has been completed. Here, since it is determined that the search has not been completed, the process returns to step S4.

  Next, the search response message REP (b0) corresponding to the context value “b0” is received at time t3 in FIG. 6, and when this is detected in step S4, the process proceeds to step S5. Here, in addition to the content recipients who have registered the context values “a0” and “b1”, the content recipients who have further registered the context value “b0” are clarified, and as a result, the above formula (2) Since the content receiver X0 that satisfies the logical product term (a0 AND b0) of the first term is newly specified as the delivery destination, the process proceeds to step S6. In step S6, the content is distributed to the peer node of the newly specified content recipient X0.

  When the search response message REP (b0) is received, in addition to the logical product term (a0 AND b1) of the second term of the above formula (2), the logical product term of the first term is received for the content recipient X1. (a0 AND b0) is also satisfied, but since the content has already been distributed to the content receiver X1, it is not regarded as a distribution destination here.

  Next, the search response message REP (a1) corresponding to the context value “a1” is received at time t4 in FIG. 6, and when this is detected in step S4, the process proceeds to step S5. Here, in addition to the content recipients who have registered the context values “a0”, “b1”, “b0”, the content recipients who have further registered the context value “a1” are clarified. Since the content receivers X0 and x2 that satisfy the logical product terms (a1 AND b0) and (a1 AND b1) of the remaining third and fourth terms of the expression (2) are newly specified as distribution destinations, the process proceeds to step S6. . In step S6, the content is distributed to the peer node of the content recipient X2 whose content has not been transmitted. In step S7, since it is determined that reception of all the search response messages REP has been completed, the process ends.

It is the figure which showed the structure of the network to which this invention is applied. It is the figure which showed the context of each content receiver. It is the figure which showed the content of the distributed hash table of each context management peer node. It is the functional block diagram which showed the structure of one Embodiment of a content delivery peer node. It is the flowchart which showed operation | movement of the content delivery peer node. It is the sequence flow which showed the communication procedure of a content delivery peer node and another peer node.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 101 ... Search condition input part, 102 ... Logical expression conversion part, 103 ... Request message transmission part, 104 ... Response message reception part, 105 ... Distribution destination specific part, 106 ... Content distribution part, 107 ... Content database, 108 ... Interface

Claims (3)

In a content distribution system in which a content receiver records its own context in advance, and the content distributor distributes content to a content receiver that matches the context search conditions.
A logical expression conversion means for converting a search condition composed of a logical product and a logical sum of contexts into a multinomial logical expression in which a plurality of logical product terms are enclosed in a logical sum;
Means for sending a search request message for requesting a search for a content recipient who has registered the context for each context;
Means for receiving a search response message that is replied to each search request message and recorded by a content receiver that registers each context;
Means for identifying a content recipient whose registered context satisfies each logical product term of the polynomial formula based on the received search response message;
A content distribution system comprising content distribution means for distributing content to the specified content recipient.   The content distribution unit distributes content only to a content recipient newly specified based on a search response message newly received by the unit for specifying the content recipient. Content distribution system. In a content distribution method in which a content receiver registers its own context in advance, and the content distributor distributes content to a content receiver that matches the context search conditions.
A procedure for converting a search condition composed of a logical product and a logical sum of contexts into a multinomial logical expression in which a plurality of logical product terms are surrounded by a logical sum,
A procedure for sending a search request message for requesting a search for a content recipient who has registered the context for each context;
A procedure for receiving a search response message that is replied to each search request message and recorded by a content receiver that registers each context;
A procedure for identifying a content recipient whose registered context satisfies each logical product term of the polynomial formula based on the received search response message;
A content distribution method comprising: a content distribution procedure for distributing content to the specified content receiver at that time when the content receiver is specified.

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