JP2013105213A - Information recommending device and method, and device and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy of recommendation by using a weighted way of item ranking, such as the order of popularity levels of different service items, the weights reflecting the frequencies at which the different services are selected by the user.SOLUTION: By an information recommending system, ranks of items in different services are weighted according to the frequencies at which the different services are selected by a user to whom the recommendation is addressed and the weighted ranking is outputted as a ranking vector for the recommendation addressee; information of an item history database for storing information on the user ID, item ID, item meta-data ID, service ID and the user's item evaluation for each of the plurality of services is represented as an adjacency matrix; and items to be recommended are calculated by using the adjacency matrix and the ranking vector.

Description

  The present invention relates to an information recommendation apparatus, method, apparatus, and program, and in particular, an information recommendation apparatus, method, and apparatus that can recommend content and items (hereinafter referred to as items) of a plurality of services in information recommendation. And the program.

  As a conventional technique, for a single service, a graph including users, items, and metadata as nodes is searched by a graph theory approach called Random Walk with Restart (RWR), and a user who receives a recommendation (hereinafter referred to as “subject”). There is a method of determining an item to be recommended (hereinafter referred to as “recommended item”) (referred to as “recommended user”) (for example, see Non-Patent Document 1).

  In addition, in order to make it possible to recommend items for a plurality of services using the method of Non-Patent Document 1, an adjacency matrix is constructed so as to integrate a plurality of services in an adjacency matrix representing a graph to be used. There is a method of realizing information recommendation in a plurality of services by supplementing the item relationship between services using the above information (see Non-Patent Document 2, for example).

Konstas, I., Stathopoulos, V. and Jose, J. M .: On social networks and collaborative recommendation, in Proc.SIGIR '09, pp. 195-202 (2009). Junta Tsutsuda, Makoto Nakatsuji, Toshiro Uchiyama, Ko Fujimura .: Cross-service recommendation using item co-occurrence on social media, 3rd Forum on Data Engineering and Information Management, DEIM '11, March 2011.

  By using the method of Non-Patent Document 2 described above, it is possible to perform information recommendation dealing with a plurality of services. However, services that are not frequently used by the recommended user and services that are frequently used by the recommended user may differ in the ease of grasping the user's preference tendency from the usage history. The method of Document 2 has a concern that the recommendation accuracy is low in a service that is not frequently used by a user among a plurality of services. In such a case, the service frequently used by the recommended user reflects the user's preference more strongly, and the service that the recommended user does not use often presents the items supported by many other users than the user's preference. The recommendation accuracy can be expected to improve.

  The present invention has been made in view of the above points, and recommends information that improves recommendation accuracy by using item rankings such as the order of popularity of items of each service according to the degree of use of each service of the user. An object is to provide an apparatus, a method, an apparatus, and a program.

In order to solve the above problems, the present invention (Claim 1) is an information recommendation device for recommending items of each service to a user in a plurality of services,
An item history database storing information on user IDs, item IDs, item metadata IDs, service IDs, and evaluation values for user items of multiple services,
Based on the inputted recommended user ID and the service ID and the item ID of the item history database, weighting is performed according to the usage degree of each service of the recommended user acquired from the service provider, Item ranking calculation processing means for outputting as a ranking vector;
An adjacency matrix construction processing means for representing information of the item history database as an adjacency matrix;
Recommended item predicted value processing means for calculating an item to be recommended using the adjacency matrix and the ranking vector.

Further, according to the present invention (Claim 2), in the item ranking calculation processing means,
Means for calculating the item ranking vector from statistics based on the appearance frequency of items in each service in the item history database and the usage frequency of each service of the recommended user.

Further, according to the present invention (Claim 3), in the recommended item prediction processing means,
Means for determining a recommended item using the ranking vector for the recommended user output from the item ranking calculation processing means and the adjacency matrix output from the adjacency matrix construction processing means.

  As described above, according to the present invention, it is possible to realize an information recommendation device that recommends items of a plurality of services with higher accuracy in consideration of the degree of use of each service of the recommended user in information recommendation.

It is a block diagram of the information recommendation apparatus in one embodiment of this invention. It is a flowchart of the adjacency matrix production | generation of the adjacency matrix provision part in one embodiment of this invention. It is an example of the table of the item history database in one embodiment of the present invention. It is an example of expression by the adjacency matrix of the item history database in one embodiment of the present invention. It is a flowchart of a process of the information recommendation system in one embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a configuration diagram of an information recommendation device according to an embodiment of the present invention. The information recommendation system shown in the figure includes a user ID acquisition unit 110, an item history database 120, an adjacency matrix providing unit 130, a recommended item prediction processing unit 140, an item ranking calculation processing unit 150, and a presentation unit 160.

  FIG. 3 is an image of a table in the item history database 120 according to an embodiment of the present invention. The database is such that user IDs, item IDs, metadata IDs, service IDs, and evaluation values for items can be referred to.

  Next, means for constructing an adjacency matrix output from the adjacency matrix providing unit 130 from the item history database 120 as shown in FIG. 3 will be described using the flowchart of FIG.

The adjacency matrix here represents the relationship between the item of each service obtained by referring to the item history database 120, the user, and the metadata as one matrix as shown in FIG. Is expressed as A, and the relationship between the matrix and its elements is expressed as A = (a _{i, j} ).

Step 210) The adjacency matrix providing unit 130, from the item history database 120,
U = {u ₁ , u ₂ ,… u _{| U |}
Set of all items I = {i ₁ , i ₂ ,… i _{| I |} },
Total metadata set M = {m ₁ , m ₂ ,… m _{| M |} }
To collect.

Step 220) A matrix A = (a _{j, k} ) having a size of | U | + | I | + | M | is prepared. j represents a user when 1 ≦ j ≦ | U |, j represents an item when | U | + 1 ≦ j ≦ | U | + | I |, and j represents metadata Is the case when | U | + | I | + 1 ≦ j ≦ | U | + | I | + | M |, and k is the same. For example, a _{j, k} = 1 (| U | + 1 ≦ j ≦ | U | + | I |, | U | + | I | + 1 ≦ k ≦ | U | + | I | + | M |) , The value representing the item j and the metadata k in the matrix is 1.

Steps 231 to 235) For all items and all metadata, 1 is substituted into matrix values a _{j, k} representing the associated combinations on the item history database 120 as follows (S233).

関連付けのない場合は以下のように、０を代入する（Ｓ２３４）。

When there is no association, 0 is substituted as follows (S234).

アイテム履歴データベース１２０上での関連付けは、図４の様なデータベース構造の場合、アイテムＩＤの列とメタデータＩＤの列を参照して同一エントリにそれぞれのＩＤが存在することを表す。

In the case of the database structure as shown in FIG. 4, the association on the item history database 120 indicates that each ID exists in the same entry with reference to the item ID column and the metadata ID column.

Steps 236 to 242) For all items and all users, values are substituted into matrix values a _{j, k} representing combinations associated with each other in the item history database 120. If the value is data such that the user gives an evaluation value to the item in the service, the evaluation value of the item i of a user u is divided by the maximum value of all the evaluation values that the user u assigned to the item. The value is substituted as follows (S241).

データベース１２０上に評価値が存在せず、例えば、POSデータのようなユーザがアイテムを購入したか否かが記録されたデータの場合は、以下のように対応する値に１を代入する（Ｓ２４０）。

In the case where there is no evaluation value on the database 120 and data such as POS data in which whether or not a user has purchased an item is recorded, for example, 1 is substituted into the corresponding value as follows (S240). ).

関連付けのない場合は以下のように０を代入する（Ｓ２３９）。

If there is no association, 0 is substituted as follows (S239).

ステップ２５０〜２７０） 行列Aを、行列の列の値の和が1になるように正規化処理を行う。具体的には、式（１）に示すように、列の値の和で値を除した値に更新し、全ての列について行ったものを、出力する隣接行列Aとする。

Steps 250 to 270) The matrix A is normalized so that the sum of the matrix column values becomes 1. Specifically, as shown in Expression (1), the value obtained by dividing the value by the sum of the column values is updated, and what is performed for all the columns is set as an output adjacency matrix A.

上記のようにして生成された隣接行列Aは当該隣接行列提供部１３０内のメモリ（図示せず）に格納しておくものとする。

Assume that the adjacency matrix A generated as described above is stored in a memory (not shown) in the adjacency matrix providing unit 130.

  Next, the process of presenting recommended items to the recommended user will be described using the configuration diagram of FIG. 1 along the flowchart of FIG.

  Step 510) First, as a recommended user ID acquisition process, the recommended user ID acquisition unit 110 acquires the ID of the recommended user and outputs the ID to the item ranking calculation processing unit 150. This process is performed at the same time as the login process to the service or system used by the user, for example.

Step 520) Upon obtaining the recommended user ID, the item ranking calculation processing unit 150 receives item ID, metadata ID, service ID, and evaluation value data from the item history database 120 based on the recommended user ID. Based on the user ID, service ID, and item ID, the service provider (provider) is accessed, and access information for each item of the service corresponding to each recommended user (the usage degree of the service of the user) is acquired. The weight according to use degree of each service of the user by applying the service degree of the user, to create a column vector r _u item ranking for the recommended user and stored in the memory (not shown). When the element r _{(u, i)} of r _u is the value of the ranking vector of item i, it is expressed by the following equation (2).

上記の式（２）において、sfreq( i )はアイテムiの関連付けられるサービスsのユーザの利用度合いを表し、例えばサービスsの利用者の利用頻度をxとした時の累積分布関数F_s(x)により、1−F_s(x) を用いることができる。この累積分布関数を用いる場合は、被推薦ユーザの中でサービスsを最も利用しているユーザ、つまり該サービスにおいてユーザの利用履歴が十分に得られる時に0に近い値となる。逆に、利用頻度の少ないユーザの場合は値が1に近い値となり、そのサービス中のアイテムの推薦結果がランキングによって補正されやすくなる。count( ) はアイテム履歴データベース１２０中での頻度を表し、その同一サービスのアイテムの集合Isの中での最大値を表すmax_i∈Is ( count( i ) ) で割ることで0から1の間の値に収める。

In the above equation (2), sfreq (i) represents the usage level of the user of the service s associated with the item i. For example, the cumulative distribution function F _s (x ), 1−F _s (x) can be used. When this cumulative distribution function is used, the value is close to 0 when the user who uses the service s most among the recommended users, that is, when the user's usage history is sufficiently obtained in the service. Conversely, for users with low usage frequency, the value is close to 1, and the recommendation result of items in the service is easily corrected by ranking. count () represents the frequency in the item history database 120, and is divided between 0 and 1 by max _i∈Is (count (i)) representing the maximum value in the set Is of items of the same service. Within the value of.

Finally, the item ranking vector r for the final recommended user is obtained by performing normalization processing of Equation (3) on r _{(u, i)} so that the sum of the vectors becomes 1 for calculation by the Random Walk model. get _u .

ステップ５３０）隣接行列提供部１３０は、アイテム履歴データベース１２０からユーザＩＤ、アイテムＩＤ、メタデータＩＤ、サービスＩＤ、評価値のデータを受け取って、前述の図２に示す手順により隣接行列Aを構築し、メモリ（図示せず）に格納する。

Step 530) The adjacency matrix providing unit 130 receives the user ID, item ID, metadata ID, service ID, and evaluation value data from the item history database 120, and constructs the adjacency matrix A according to the procedure shown in FIG. And stored in a memory (not shown).

  Step 540) The recommended item prediction processing unit 140 acquires the recommended user ID and the item ranking for the recommended user from the item ranking calculation processing unit 150, acquires the adjacent matrix from the adjacent matrix providing unit 130, and uses these. Decide which items to recommend. In the calculation, Random Walk with Restart (RWR), which determines the relevance between the acquired recommended user ID and each item ID and recommends an item with a high value, is improved so that the ranking can be considered. Use.

Specifically, p ^(t) is a column vector of the degree of relevance of items at the calculation step t, and α and β are 0 <α <1, 0 <β <1, and 0 <α + β <1, respectively. A constant to satisfy, A is an adjacency matrix, a probability α, q to return to the starting node is a column vector in which only the starting node representing the recommended user is 1, and _ru is for the recommended user output by the item ranking calculation processing unit 150 Assuming a ranking column vector, it is expressed as shown in Equation (4).

式（４）の計算は隣接行列A上でt回繰り返してp^(t) が更新され、p^(t) の列ベクトルからアイテムを表すノードの関連度の高いものを推薦アイテムとして出力する。ここでのtは100回とする。なお、この実施回数は100回に限定されることなく、十分に大きな値であればよい。
ステップ５５０）推薦アイテム提示処理として提示部１６０は、推薦アイテム予測処理部１４０の出力である推薦アイテムを提示し、推薦が完了する。

The calculation of Expression (4) is repeated t times on the adjacency matrix A, p ^(t) is updated, and a node item representing a high degree of relevance from the column vector of p ^(t) is output as a recommended item. Here, t is 100 times. The number of implementations is not limited to 100, and may be a sufficiently large value.
Step 550) As the recommended item presentation process, the presentation unit 160 presents the recommended item that is the output of the recommended item prediction processing unit 140, and the recommendation is completed.

  In the above-described step 520, an example is shown in which the service usage level for each recommended user is acquired from the service provider. However, the present invention is not limited to this example. A database storing information may be provided and acquired from the database.

  With the above processing, it is possible to recommend items by changing the degree of reflection (weight) of the ranking result according to the service usage status.

  The operation of the information recommendation device including the recommended user ID acquisition unit 110, the adjacency matrix providing unit 130, the recommended item prediction processing unit 140, and the item processing unit 160 in FIG. 1 is constructed as a program and used as an information recommendation device. It can be installed and executed on a computer to be distributed, or distributed via a network.

  The present invention is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the claims.

110 non-recommended user ID acquisition unit 120 item history database 130 adjacency matrix providing unit 140 recommended item prediction processing unit 150 item ranking calculation processing unit 160 item presentation unit

Claims (7)

An information recommendation device for recommending an item of each service to a user in a plurality of services,
An item history database storing information on user IDs, item IDs, item metadata IDs, service IDs, and evaluation values for user items of multiple services,
Based on the inputted recommended user ID and the service ID and the item ID of the item history database, weighting is performed according to the usage degree of each service of the recommended user acquired from the service provider, Item ranking calculation processing means for outputting as a ranking vector;
An adjacency matrix construction processing means for representing information of the item history database as an adjacency matrix;
A recommended item predicted value processing means for calculating an item to be recommended using the adjacency matrix and the ranking vector;
An information recommendation device comprising: The item ranking calculation processing means includes:
The information recommendation device according to claim 1, further comprising means for calculating the item ranking vector from statistics based on the appearance frequency of items in each service in the item history database and the usage frequency of each service of the recommended user. The recommended item prediction processing means includes:
A means for calculating a recommended item using the ranking vector for the recommended user output from the item ranking calculation processing means and the adjacency matrix output from the adjacency matrix construction processing means. 1. The information recommendation device according to 1. An information recommendation method for recommending items of each service to users in a plurality of services,
In the information recommendation device having the item history database storing information on user IDs, item IDs, item metadata IDs, service IDs, and evaluation values of items of users of each of a plurality of services,
The item ranking calculation processing means, based on the inputted recommended user ID and the service ID and the item ID of the item history database, according to the use degree of each service for each recommended user acquired from the service provider Item ranking calculation processing step for weighting and outputting as a ranking vector for the recommended user;
An adjacency matrix construction processing means, an adjacency matrix construction processing step representing information of the item history database as an adjacency matrix;
A recommended item predicted value processing means for calculating an item to be recommended using the adjacency matrix and the ranking vector;
Recommending information. In the item ranking calculation processing step,
5. The information recommendation method according to claim 4, wherein the item ranking vector is calculated from statistics based on an appearance frequency of an item in each service in the item history database and a usage frequency of each service of the recommended user. In the recommended item prediction processing step,
5. The information according to claim 4, wherein calculation for determining a recommended item is performed using the ranking vector for the recommended user acquired in the item ranking calculation processing step and the adjacency matrix acquired in the adjacency matrix construction processing step. Recommendation method. Computer
The information recommendation program for functioning as a means of the information recommendation apparatus of any one of Claims 1 thru | or 3.

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