Content display device and program

Abstract

To provide a content presentation device and a program that can present the relation between contents in a visually easy-to-understand manner.SOLUTION: A relationship data storage unit stores the set of pairs of phrases having a specific relationship as relationship data. A metadata storage unit stores, for every content, metadata including information on the phrases representing the content. A content searching unit reads out, from the relationship data storage unit, related phrases paired with the phrases included in the metadata related to a first content, refers to the metadata storage unit to determine a related content including the related phrases as the metadata, and recursively determines a further related content with the determined related content as the first content. A display unit, based on the latest viewed content being a content viewed in the latest period, displays the latest viewed content and the related content in a form of a graph.SELECTED DRAWING: Figure 1

Description

Technical Field

[0005] ,

[0004] , , ,

[0001] The present invention relates to a content presentation device and a program.

Background Art

[0002] In recent years, with the spread of curation services that collect and present articles on the Internet, research on methods for associating contents with each other, such as presenting articles related to a certain article or related videos, has been actively conducted. In particular, in the field of education, it is also expected to use contents composed of videos, voices, images, etc. in a form suitable as learning materials by associating them.

[0003] Patent Document 1 describes a technique for presenting appropriate related contents in order to cover the contents of the content. In the technique described in Patent Document 1, a search for related contents is performed in consideration of the degree of overlap of keywords. Therefore, it is possible to present related contents that can explain the contents of the content without omission and duplication to the maximum extent.

[0004] Patent Document 2 describes a content presentation device that can search for programs from an archive of television programs over the past few decades with a simple user interface that has not existed before. In the technique described in Patent Document 2, a user can easily search for contents of a specific era in a form associated with his / her age.

[0005] Non-Patent Document 1 describes a method for searching for related contents by using the similarity of explanatory texts describing the contents of video contents as the similarity of video contents. The method described in Non-Patent Document 1 also selects and outputs a sentence that best represents the common linguistic features between the sentence constituting the text indicating the content of the specified content and the sentence selected as related content from the text indicating the content of the specified content. Thereby, it becomes possible to present information on how the contents are related to each other from what viewpoints. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2017-142573 [Patent Document 2] Japanese Patent Publication No. 2018-010607 [Non-patent literature]

[0007] [Non-Patent Document 1] "Related Content Search Technology", NHK Technical Catalog, NHK Engineering Systems Foundation, [online], [Accessed April 1, 2022], Internet,<URL:https: / / www.nes.or.jp / transfer / catalog / langprocess_03.html> [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, each of the conventional technologies described above had the following problems.

[0009] While the technology described in Patent Document 1 makes it possible to present related content that explains the content as comprehensively and without redundancy as possible, it does not present the relationships between the content in a visually easy-to-understand manner.

[0010] The technology described in Patent Document 2 has the problem that while relationships between content items in a chronological order are visually presented, the relationships between content items in a specific era are not shown. In other words, with the technology described in Patent Document 2, users cannot grasp the relationships between content items in a specific era.

[0011] The technology described in Non-Patent Document 1 only presents relationships where elements are related (common) in a certain respect, and fails to present other relationships. For example, the technology in Non-Patent Document 1 does not present relationships in terms of the learning order of multiple learning contents. Furthermore, the technology in Non-Patent Document 1 only presents related content directly related to a specified content, and does not provide an interface that allows users to grasp chain-like relationships, such as further related content of related content, at a glance.

[0012] Conventional methods for presenting related content do not provide an interface that allows users to understand the relationship between the presented related content and the original content. In other words, when there are many related pieces of content, users are not given enough information to select the appropriate content from among them. In the field of education in particular, clearly showing the relationships between content is important from the perspective of making learning time more efficient. Clearly showing the relationships between content is important not only in promoting user understanding but also in broadening users' interests. Furthermore, being able to visually grasp the chain-like relationships between content, such as related content being related to further related content, is also useful in planning content viewing.

[0013] This invention was made in consideration of the circumstances described above, and aims to provide a content presentation device and program that can visually present the relationships between content in an easy-to-understand manner. [Means for solving the problem]

[0014] To solve the above problems, [1] A content presentation device according to one aspect of the present invention includes: a relationship data storage unit that stores a set of pairs of words having a specific relationship as relationship data; a metadata storage unit that stores metadata for each piece of content that includes information about words representing the content; a content search unit that reads from the relationship data storage unit related to words that are paired with words in the metadata relating to the first piece of content, determines related content that includes the related words as metadata by referring to the metadata storage unit, and further determines further related content by recursively using the determined related content as the first piece of content; and a display unit that displays information about content determined by the content search unit as related content that is directly or indirectly related to the most recently viewed content, based on the most recently viewed content, the display unit displays information about the most recently viewed content and related content that is directly or indirectly related to the most recently viewed content in the form of a graph in which the first piece of content and the related content each are represented as nodes, and the relationship between the first piece of content and the related content directly related to the first piece of content is represented as an edge.

[0015] [2] In another embodiment, the content display device described in [1] further comprises a viewing data acquisition unit that acquires viewing data including viewing history information for the content that has been viewed, and the display unit displays the graph by marking nodes corresponding to the content included in the viewing data with a viewed mark.

[0016] [3] In another embodiment, in the content presentation device described in [1] or [2] above, when the display unit is instructed to display an enlarged display screen, it enlarges and displays only graphs in which the distance of the number of stages of relationship between nodes is M or less (where M is a non-negative integer set as appropriate), starting from a specific content.

[0017] [4] In another embodiment, in any of the content display devices described in [1] to [3] above, the display unit displays information on the edge indicating the type of relationship represented by the edge and, if the relationship has a direction, the direction thereof.

[0018] [5] In another embodiment, the content display device of any of the above [1] to [4] further comprises an operation unit that receives an operation by a user to select a specific edge, wherein the display unit displays a pair of words associated with the edge with respect to the selected edge received by the operation unit.

[0019] [6] In another embodiment, a content presentation device according to any of the above [1] to [5] further comprises a relationship extraction device which extracts relationship data representing the relationships between words and phrases based on document data and writes the extracted relationship data to the relationship data storage unit, wherein the relationship extraction device comprises an important word extraction unit which extracts important words from words and phrases included in at least one of the title and the body of the document data which includes the title and the body of the document, and a basic development relationship extraction unit which determines as development words the important words selected from the important words extracted by the important word extraction unit on the condition that they are words included in the title, determines as basic words the important words that were not selected as development words, and extracts pairs of the determined basic words and the determined development words as basic development relationships.

[0020] [7] Another embodiment is a program that causes a computer to function as a content presentation device, comprising: a relationship data storage unit that stores a set of pairs of words having a specific relationship as relationship data; a metadata storage unit that stores metadata for each piece of content that includes information about words representing the content; a content search unit that reads from the relationship data storage unit related to words that are paired with words contained in the metadata relating to the first piece of content, determines related content that includes the related words as metadata by referring to the metadata storage unit, and further determines further related content with the determined related content as the first piece of content; and a display unit that displays information about content determined by the content search unit as related content that is directly or indirectly related to the most recently viewed content, based on the most recently viewed content, the most recently viewed content, wherein the display unit displays information about the most recently viewed content and related content that is directly or indirectly related to the most recently viewed content in the form of a graph in which the first piece of content and the related content each are represented as nodes, and the relationship between the first piece of content and the related content directly related to the first piece of content is represented as an edge.

[0021] [A] In another embodiment, in the content presentation device described in [6] above, the important word extraction unit extracts important words from each of the multiple document data, each of which includes a title and body text, and the multiple document data are ordered, and the basic development relationship extraction unit determines as development words important words selected from among the important words extracted by the important word extraction unit, on the condition that the words included in the title are newly appearing words based on the order of the document data.

[0022] [B]Furthermore, as one aspect, in the content presentation device of [6] above, a document conversion unit that generates a synthetic sentence, which is data obtained by concatenating the title and the text, based on the document data including the title and the text, is further provided, and the important phrase extraction unit may extract the important phrases by performing an analysis process on the synthetic sentence.

Effects of the Invention

[0023] According to the present invention, the content presentation device displays related content directly or indirectly related to the specific content in the form of a graph, starting from a node corresponding to the specific content (the most recently viewed content). That is, the user can easily and visually grasp the relationship between the contents at a glance.

Brief Description of the Drawings

[0024] [Figure 1] It is a block diagram showing a schematic functional configuration of a content presentation system according to a first embodiment of the present invention. [Figure 2] It is a schematic diagram showing an example of data representing a basic development relationship stored in a relationship data storage unit according to the first embodiment. [Figure 3] It is a schematic diagram showing an example of viewing data stored in a viewing data storage unit according to the first embodiment. [Figure 4] It is a schematic diagram showing an example of display on an overall display screen displayed by a display unit of a content presentation device according to the first embodiment. [Figure 5] It is a schematic diagram showing an example of display on an enlarged display screen displayed by a display unit of a content presentation device according to the first embodiment. [Figure 6] It is a schematic diagram showing an example of display on an enlarged display screen displayed by a display unit of a content presentation device according to the first embodiment, and displays a pair of phrases corresponding to an edge. [Figure 7] It is a flowchart (1 / 2) showing a procedure of processing by a content presentation device in a receiving device according to the first embodiment. [Figure 8]This is a flowchart (2 / 2) showing the processing procedure by the content presentation device in the receiving device according to the first embodiment. [Figure 9] This is a block diagram showing the schematic functional configuration of a content presentation system according to a second embodiment of the present invention. [Figure 10] This is a block diagram showing the functional configuration of the relation extraction device in the second embodiment. [Figure 11] This block diagram shows a more detailed functional configuration of the basic development relationship extraction unit according to the second embodiment. [Figure 12] This is a schematic diagram showing an example of one document data item acquired by the document acquisition unit of the basic development relationship extraction unit according to the second embodiment. [Figure 13] This is a schematic diagram showing another example of a single document data item acquired by the document acquisition unit of the basic development relationship extraction unit according to the second embodiment. [Figure 14] This is a schematic diagram showing the relationship between the document conversion process performed by the document conversion unit according to the second embodiment and its input and output data. [Figure 15] This is a schematic diagram showing an example of document data after the document conversion unit according to the second embodiment has performed the conversion process. [Figure 16] This is a schematic diagram showing an example of a basic development relationship list generated and output by the basic development relationship list output unit according to the second embodiment. [Figure 17] This is a schematic diagram showing another example of a basic development relationship list generated and output by the basic development relationship list output unit according to the second embodiment. [Figure 18] This flowchart shows the procedure for the basic development relationship extraction unit according to the second embodiment to extract basic development relationships based on document data. [Figure 19] This block diagram shows examples of the internal configuration of a device for configuring a content processing system according to the first and second embodiments, respectively. [Modes for carrying out the invention]

[0025] Next, several embodiments of the present invention will be described with reference to the drawings. All of the embodiments described below relate to the fields of content distribution by broadcast, distribution by communication network, or hybrid distribution spanning both broadcast and the network. Each embodiment provides a visual graphical user interface that clearly indicates the relationships between content and viewing history. This user interface allows users to easily select the next content to view, etc.

[0026] [First Embodiment] In the content presentation system of the first embodiment, the receiving device 10 provides a visual graphical user interface (GUI) that clearly indicates the relationships between content and the content viewing history for content distributed via the Internet. This allows the user to easily select the next content to view, for example, after finishing viewing a certain piece of content. The content consists of video, audio, and other data.

[0027] The receiving device 10 (content presentation device 1) of this embodiment presents information indicating the relationship between related content and content viewed by the user. The receiving device 10 also presents information regarding the content viewing history. Furthermore, the receiving device 10 presents this information in a visually easy-to-understand manner using a graphical user interface. Through these measures, the receiving device 10 helps the user appropriately select the next content to view.

[0028] Figure 1 is a block diagram illustrating the schematic functional configuration of the content presentation system according to this embodiment. As shown in the figure, the content presentation system 50 consists of a distribution server device 7, the Internet 8, and a receiving device 10. Although only one receiving device 10 is shown in this figure, there may be multiple receiving devices 10 within the content presentation system 50. In that case, the distribution server device 7 distributes content in response to requests from each receiving device 10.

[0029] At least some of the functions of the distribution server device 7 and the receiving device 10 can be implemented, for example, by a computer and a program. Furthermore, each of these functions may have storage means as needed. These storage means may be, for example, variables in the program or memory allocated during program execution. Alternatively, non-volatile storage means such as magnetic hard disk drives or solid-state drives (SSDs) may be used as needed. Also, at least some of the functions of each functional unit may be implemented as dedicated electronic circuits rather than programs.

[0030] The distribution server device 7 is a device that distributes video content to the receiving device 10. The distribution server device 7 is implemented, for example, using a server-type computer. The distribution server device 7 transmits content to the receiving device 10 via communication over the Internet 8. The distribution server device 7 stores multiple (many) pieces of content and reads the selected content from the storage means upon request from the receiving device 10 and transmits it to the receiving device 10. The distribution server device 7 may distribute at least some of the content via broadcast signals instead of communication over the Internet.

[0031] Internet 8 is a communication network for communication between devices. Communication on Internet 8 uses the Internet Protocol. In this embodiment, communication between the distribution server device 7 and the receiving device 10 is conducted via Internet 8.

[0032] The receiving device 10 receives and displays content distributed from the distribution server device 7. In other words, users of the receiving device 10 can view content distributed from the distribution server device 7. The receiving device 10 also includes a content presentation device 1 internally, which can present content related to a given piece of content (for example, content viewed by the user) to the user (referred to as related content). The detailed functional configuration of the receiving device 10 will be explained later. The receiving device 10 can be implemented using, for example, a personal computer (PC), a tablet device, a smartphone, a wristwatch-type terminal device, or other wearable devices.

[0033] As shown in Figure 1, the receiving device 10 is composed of a content presentation device 1, a playback control unit 3, and a viewing data storage unit 4.

[0034] Content presenter 1 presents information about content to the user. Specifically, content presenter 1 displays information representing the relationships between multiple pieces of content. Therefore, content presenter 1 has the function of searching for content related to a given piece of content (referred to as related content) based on metadata for each piece of content and relationships between pre-determined keywords. In addition, content presenter 1 displays information indicating which piece of content was viewed most recently among multiple pieces of content. Furthermore, content presenter 1 displays information indicating which pieces of content the user has already viewed. A more detailed explanation of the functional configuration of content presenter 1 will be provided later.

[0035] The playback control unit 3 controls the playback of content on the receiving device 10. Specifically, the playback control unit 3 requests content from the distribution server device 7 based on user operations (requests), receives the content via the Internet 8, and plays it. In other words, the playback control unit 3 decodes the video and audio contained in the received content, displays the video on the screen of the receiving device 10, and outputs the audio from speakers, etc. The playback control unit 3 writes viewing data to the viewing data storage unit 4 as a record of content playback. The contents of the viewing data will be explained later. By having the playback control unit 3 write and save the viewing data to the viewing data storage unit 4, the content presentation device 1 can know which content the user has already viewed. In addition, the playback control unit 3 writes the viewing start date and time and viewing end date and time information as part of the viewing data to the viewing data storage unit 4 for each piece of content. By referring to this date and time information, the content presentation device 1 can know which content was viewed most recently.

[0036] The viewing data storage unit 4 stores viewing data. Viewing data represents the user's viewing history of content. The viewing data includes information identifying the content, as well as information on the viewing start date and time, and viewing end date and time. The viewing data is accumulated within the viewing data storage unit 4. An example of the viewing data configuration will be explained later with reference to Figure 3.

[0037] As shown in Figure 1, the detailed functional configuration of the content presentation device 1 is as follows. The content presentation device 1 includes a metadata storage unit 101, a relationship data storage unit 102, a viewing data acquisition unit 103, a content search unit 104, a display unit 105, and an operation unit 106.

[0038] The metadata storage unit 101 stores metadata for each piece of content. The metadata includes attribute information of the content. Specifically, the metadata includes information such as the URL for accessing the content, the content name, one or more keywords (phrases) related to the content, and a description of the content (text consisting of multiple phrases). In other words, the metadata storage unit 101 stores metadata for each piece of content that includes information about phrases representing the content. The URL information of the content mentioned above may be used as identification information to uniquely identify the content. The metadata can be represented, for example, as tabular data (relational data). The metadata can also be represented, for example, as RDF (Resource Description Framework) format data, or as data in other formats.

[0039] The relationship data storage unit 102 stores data representing the relationships between words. Specifically, the relationship data storage unit 102 stores a set of pairs of words having a specific relationship as relationship data. One example of a relationship between words is a "basic-advanced relationship." This basic-advanced relationship corresponds, for example, to the relationship between "basic" and "advanced" in learning content. This basic-advanced relationship can serve as a guide for the order in which learning content is viewed (learning order). The relationship data storage unit 102 may also store information about relationships between words other than the basic-advanced relationship described above. These relationships may include, for example, "superior-subordinate relationships" or other types of relationships.

[0040] The content presentation device 1 can import relationship data from, for example, another device and store it in the relationship data storage unit 102.

[0041] The viewing data acquisition unit 103 acquires the user's viewing data stored in the viewing data storage unit 4. In other words, the viewing data acquisition unit 103 acquires viewing data that includes viewing history information about the content that has been viewed. As mentioned above, the viewing data includes information on the viewing end date and time for each piece of content viewed by the user. The viewing data acquisition unit 103 refers to the viewing end date and time information for each piece of content included in the viewing history and determines that the content with the latest viewing end date and time (the largest value) is the most recently viewed content. The viewing data acquisition unit 103 passes information (e.g., URL) that uniquely identifies the most recently viewed content (referred to as recently viewed content) to the content search unit 104 and the display unit 105. The viewing data acquisition unit 103 also passes information (e.g., URL) that uniquely identifies all other viewed content to the content search unit 104 and the display unit 105.

[0042] The content search unit 104 searches for content related to a specific piece of content. Specific content refers to, for example, recently viewed content. As mentioned above, the content search unit 104 receives information that identifies the recently viewed content (for example, the URL of the recently viewed content) from the viewing data acquisition unit 103.

[0043] The search procedure performed by the content search unit 104 is as follows: First, the content search unit 104 refers to the metadata storage unit 101 based on information that identifies a specific content and obtains keywords related to that content. The number of keywords obtained by the content search unit 104 may be singular or multiple. When there are multiple keywords, the important keywords for that content may be selected from among the multiple keywords by referring to the relationship data storage unit 102. Specifically, the advanced words corresponding to each keyword are obtained from the relationship data storage unit 102, and when a keyword corresponding to the advanced word exists among multiple keywords, only the advanced word is adopted as the keyword and the basic word is not adopted, thereby assigning the keyword that best expresses the theme to be learned in that content (the most advanced content within the content). Next, the content search unit 104 obtains other words related to each of those keywords by referring to the relationship data storage unit 102. Specifically, the basic words and advanced words corresponding to the keywords of the specific content are obtained from the relationship data storage unit 102. The content search unit 104 then retrieves information about content that has the words obtained from the relationship data storage unit 102 as keywords from the metadata storage unit 101. In other words, the content search unit 104 identifies content that has keywords with such relationships (e.g., basic-development relationships) as related content. The content search unit 104 can also search for related content in multiple stages. That is, when there is content related to the original content (related content), the content search unit 104 retrieves information about other content further related to that related content from the metadata storage unit 101. The same process continues thereafter, and the content search unit 104 searches for content related to the original content in a chain-like fashion. The content search unit 104 may stop searching for multi-stage related content when certain conditions are met (for example, when there is no more related content, when the number of stages of relationship reaches a predetermined threshold, or when the total number of retrieved related content exceeds a predetermined threshold).

[0044] The content search unit 104 can obtain information on a large number of content items related to the original content (for example, recently viewed content) by following the procedure described above.

[0045] In other words, the content search unit 104 reads related terms that are paired with the terms contained in the metadata of the first content (the content that serves as the starting point for tracing a one-level relationship) from the relationship data storage unit 102, and by referring to the metadata storage unit 101, it determines related content (content that is related to the first content through a one-level relationship) that contains those related terms as metadata, and further determines even more related content by using the determined related content as the first content. The content search unit 104 can search by tracing relationships in multiple levels.

[0046] The display unit 105 receives the search results information from the content search unit 104 and displays a graph representing the relationships between the content on the screen of the receiving device 10. Specifically, the display unit 105 creates a graph with each content as a node and the relationships between the content as edges, and displays the graph graphically on the screen. The graph displayed by the display unit 105 may be a directed graph or an undirected graph. The display unit 105 may also display names representing the relationships along with the edges. The display unit 105 may also display the relationships between words that form the basis of the relationships between the content (basic words and advanced words) within the graph. Furthermore, the display unit 105 may indicate that the content has been viewed on nodes corresponding to viewed content, based on the information of viewed content received from the viewing data acquisition unit 103. Furthermore, the display unit 105 may indicate that the content has been recently viewed on nodes corresponding to recently viewed content, based on the information of recently viewed content received from the viewing data acquisition unit 103. The display unit 105 may also enlarge the display of nodes within a predetermined range in the graph. Here, "within a predetermined range" refers to the range of content that has a relationship with the most recently viewed content within M steps (hops). M is a predetermined non-negative integer. For example, M = 2.

[0047] In other words, the display unit 105 displays information about content determined by the content search unit 104 to be related content that is directly or indirectly related to a specific content (for example, recently viewed content) based on that specific content (for example, recently viewed content). The display unit 105 displays information about the specific content (recently viewed content) and related content that is directly or indirectly related to that specific content in the form of a graph, for example, by representing the first content (content that serves as a starting point for tracing a one-level relationship) and related content (content that is related to the first content through a one-level relationship) as nodes, and representing the relationship between the first content and the related content that is directly related to that first content as edges.

[0048] Furthermore, the display unit 105 may display a graph (as illustrated in Figures 5 and 6) with a "viewed" mark attached to nodes corresponding to content included in the viewing data. A "viewed" mark is any form of display information that indicates that a certain piece of content has been viewed by a user.

[0049] Furthermore, when the display unit 105 is instructed to display an enlarged screen based on user operation, it can enlarge only the graphs where the distance between the number of relationship levels between nodes is M or less (where M is a non-negative integer set as appropriate), starting from a specific piece of content (for example, recently viewed content) (as illustrated in Figure 5).

[0050] Furthermore, the display unit 105 can display information attached to the edges in the graph, indicating the type of relationship represented by the edge (for example, a basic-development relationship) and, if the relationship has a direction, that direction (for example, which side of the two nodes connected by the edge corresponds to the "basic" word and which side corresponds to the "development" word) (as illustrated in Figures 5 and 6).

[0051] Furthermore, when the operation unit 106 receives an operation from the user to select a specific edge, the display unit 105 displays a pair of words associated with the edge selected by the user (as illustrated in Figure 6). For example, if there is a basic-development relationship between the basic word "atmosphere" and the developed word "carbon dioxide," and an edge corresponding to this pair of words is selected, the display unit 105 displays the word "atmosphere" at one end of the node of that edge and the word "carbon dioxide" at the other end of the node of that edge.

[0052] Specific examples of screen displays by the display unit 105 will be explained later with reference to Figures 4, 5, and 6.

[0053] The operation unit 106 has the function of realizing the user interface in the receiving device 10. The operation unit 106 accepts operations such as the user selecting a predetermined object on the screen, and causes the receiving device 10 to perform a predetermined operation according to the content of that operation. Objects on the screen include buttons displayed on the screen, nodes or edges that make up a graph, etc. In other words, the operation unit 106 may accept operations from the user to select a specific edge. Operations to select an object include, for example, touch operations on a screen equipped with a touch panel, or clicking on an object displayed on the screen using a pointing device such as a mouse.

[0054] For example, when the "Full Display" button displayed on the screen is selected, the operation unit 106 switches the screen to the full display view. Alternatively, when the "Zoomed In" button displayed on the screen is selected, the operation unit 106 switches the screen to the zoomed-in view. Also, when a node displayed on the screen is selected, the operation unit 106 operates the receiving device 10 (playback control unit 3) to acquire and play the content corresponding to that node from an external source. Furthermore, when an edge displayed on the screen is selected, the operation unit 106 causes the display unit 105 to display information about the relationship represented by that edge (for example, the base word and advanced word represented by that edge).

[0055] Figure 2 is a schematic diagram showing an example of data representing basic and advanced relationships stored in the relational data storage unit 102. As shown in the figure, basic and advanced relationships can be represented, for example, as tabular data. The tabular data shown represents the correspondence between words (phrases, expressions) corresponding to "basic" and words (phrases, expressions) corresponding to "advanced". In the example shown in Figure 2, the basic word "atmosphere" corresponds to the advanced word "carbon dioxide" (data in the first row). Also, the basic word "force" corresponds to the advanced word "work" (data in the second row). Also, the basic word "work" corresponds to the advanced word "potential energy" (data in the third row). In reality, the relational data storage unit 102 stores correspondences between many other words and phrases in addition to the relationships exemplified here.

[0056] Figure 3 is a schematic diagram showing an example of viewing data stored in the viewing data storage unit 4. The viewing data represents a record of content viewed by a user on a specific receiving device 10. As shown in the figure, the viewing data can be represented, for example, as tabular data. The table shown in Figure 3 has data items such as URL (Uniform Resource Locator), viewing start date and time, and viewing end date and time. Note that one row of data in the viewing data table corresponds to viewing one piece of content. The URL is location information for accessing the viewed content. The URL can also be used as identification information to uniquely identify the content. The viewing start date and time and viewing end date and time are the date and time when the user started and ended viewing the content using the receiving device 10, respectively.

[0057] The viewing data storage unit 4 may also store data other than the items shown in Figure 3 as viewing data. The viewing data may include, for example, user identification information to uniquely identify a user, regional information (information about the geographical location where the receiving device 10 is located), latitude and longitude information measured by GPS (Global Positioning System), user gender information, user age information, information representing the type of viewing device (receiving device 10), information about the user's viewing time, or information about the user's behavioral history.

[0058] The playback control unit 3 in the receiving device 10 writes the above-mentioned viewing data to the viewing data storage unit 4 when it receives and plays content from the distribution server device 7. The viewing data acquisition unit 103 acquires the viewing data stored in the viewing data storage unit 4 for the process of presenting the content.

[0059] Figure 4 is a schematic diagram showing an example of a display by the overall display screen shown by the display unit 105 of the content presentation device 1. In the overall display screen shown, the display unit 105 displays specific content and related content associated with that content using a graphical user interface. As shown in the figure, the display unit 105 displays the relationships between content in graph form. In this graph, each node corresponds to content. The edges connecting the nodes represent the relationships between content. In the figure, node 201 is a node representing specific content. Specific content is, for example, content that the user has most recently viewed (most recently viewed content). Node 202 is a node other than node 201. Node 202 is a node that is directly or indirectly related to node 201, which corresponds to the specific content. The relationships between nodes may be, for example, a basic-development relationship (described later), but other relationships may also be possible. A basic-development relationship refers to the relationship between basic content and developmental content that has advanced content derived from the basic content, as a relationship between content. In the illustrated example, the display unit 105 displays all nodes (nodes 202) that have a direct or indirect relationship with node 201.

[0060] In the lower left corner of the overall view screen shown in Figure 4, a zoom button 221 is displayed. When the user selects this zoom button 221, the display unit 105 switches the screen display from the overall view screen to the zoom view screen. Button selection is performed, for example, by the user touching a button on the screen or clicking a button on the screen with the mouse. The zoom view screen will be explained later with reference to another figure.

[0061] For example, when a user finishes watching a piece of content, the display unit 105 searches for other content related to the most recently watched content (corresponding to node 201) and displays an overall view screen, as illustrated in Figure 4, as information in a graph representing the relationships between those pieces of content. Furthermore, the user can transition from the enlarged view screen (described later) to the overall view screen through user interaction.

[0062] The display unit 105 displays an overall display screen as shown in Figure 4, allowing the user to visually grasp the relationships between the contents. In other words, the user can easily select the next content to watch after understanding the relationships between the contents. In the overall display screen shown in Figure 4, if the user selects a node (by touching the screen or clicking with the mouse, etc.), the receiving device 10 may request the distribution server device 7 to distribute the content corresponding to the selected node in order to receive that content.

[0063] Now, let's explain the distance in terms of the number of steps of association between nodes (i.e., between contents). In Figure 4, node 201, which represents the most recently viewed content, shows the letter "A". The node adjacent to this "A" node shows the letter "P". These "A" nodes and "P" nodes have a direct relationship with each other. That is, the distance in terms of steps between the "A" node and the "P" node is 1. From this "P" node onward, each time the distance in terms of association steps increases by one, the nodes show the letters "Q", "R", "S", "T", "U", "V", and "W" in order. In other words, the distance in terms of steps between the "A" node and the "Q" node is 2, the distance in terms of steps between the "A" node and the "R" node is 3, and so on, until the distance in terms of steps between the "A" node and the "W" node is 8.

[0064] Figure 5 is a schematic diagram showing an example of a display by the enlarged display screen shown by the display unit 105 of the content presentation device 1. The enlarged display screen shown in this figure displays only the nodes corresponding to content whose relationship step number distance from the most recently viewed content is M or less (M is a non-negative integer set as appropriate, and in the example shown, M=2), in an enlarged view. Also, in the screen of this figure, 231 is the reduced-size overall display screen. In this example, the reduced-size overall display screen 231 is a reduced-size display of the graph that was displayed on the overall display screen in Figure 4. The area represented by the dashed line within the reduced-size overall display screen 231 is the enlarged display area 232. In other words, the graph within this enlarged display area 232 is displayed enlarged on the enlarged display screen.

[0065] In the enlarged view shown in Figure 5, node 201 representing the most recently viewed content and node 202 representing related content are displayed. Regarding node 201, the display unit 105 indicates that it is the most recently viewed content by, for example, changing its color from other nodes (node ​​202 representing related content), painting it with a different pattern, or changing the appearance of its border (for example, by showing it with a thick line).

[0066] In the enlarged view shown in Figure 5, a full view button 222 is displayed in the lower left corner. When the user selects this full view button 222, the display unit 105 switches the screen display from the enlarged view to the full view (Figure 4). As already explained in Figure 4, button selection is performed, for example, by the user touching a button on the screen or clicking a mouse on a button on the screen.

[0067] The enlarged view shown in Figure 5 displays names (phrases) that represent the relationships between the contents. Specifically, the phrase "basic" is displayed at one end of the edge connecting the nodes, and the phrase "development" is displayed at the other end. This indicates that the relationship between the contents is a basic-development relationship, and that which side of the two nodes connected by the edge is basic and which side is development. In other words, in the display example shown in Figure 5, the direction of the relationship between the contents is indicated by the phrases. The display unit 105 may also indicate the direction of the relationship between the contents by the shape of a graphic (for example, by using arrow lines to represent the edges between nodes) rather than by the phrases. In addition, in the enlarged view shown in Figure 5, the display unit 105 marks nodes corresponding to content that the user has already viewed with the "viewed" mark. As mentioned above, the display unit 105 obtains information from the viewing data acquisition unit 103 indicating whether or not each piece of content has been viewed.

[0068] The user can select an edge displayed on the enlarged screen. Edge selection is performed, for example, by the user touching a specific edge on the screen with a touch panel with their finger, or by the user clicking the mouse while the mouse cursor is positioned on a specific edge on the screen. In this embodiment, when the operation unit 106 detects an edge selection, the display unit 105 displays the basic and advanced words associated with that edge. The display form after the user has selected an edge on the enlarged screen is shown in Figure 6, which will be described next.

[0069] Figure 6 is a schematic diagram showing an example of a display using the enlarged display screen shown by the display unit 105 of the content presentation device 1. The display shown in Figure 6 assumes that an edge connecting the node labeled A and the node labeled B is selected in the screen display shown in Figure 5. In other words, when the user selects the edge connecting the node labeled A and the node labeled B, the display unit 105 displays the basic word phrase 241 and the advanced word phrase 242, as shown in Figure 6. In this example, the basic word phrase 241 is "atmosphere," and the advanced word phrase 242 is "carbon dioxide." The relationship between the basic word "atmosphere" and the advanced word "carbon dioxide" is illustrated in the first row of Figure 2 (basic-advanced relationship data). Note that, as shown in Figure 6, the display unit 105 may also display an arrow line from the basic word phrase 241 to the advanced word phrase 242.

[0070] Next, the processing procedure of the content presentation device 1 will be described.

[0071] Figures 7 and 8 are flowcharts showing the processing procedure by the content presentation device 1 within the receiving device 10. Figures 7 and 8 illustrate a series of processing steps and are linked by a connector. When playback of a certain content is completed in the receiving device 10, the process shown in this flowchart is called, and the content presentation device 1 presents related content. It is assumed that viewing data, metadata related to the content, and relationship data between words have already been acquired and stored in the receiving device 10 before the execution of the process shown in this flowchart begins. The following explanation will follow this flowchart.

[0072] First, in step S501 in Figure 7, the viewing data acquisition unit 103 reads the viewing data of the most recently viewed content (most recently viewed content) from the viewing data storage unit 4. This viewing data is written to the viewing data storage unit 4 by the playback control unit 3 when playback of the content ends. Among the viewing data stored in the viewing data storage unit 4, the viewing data with the latest viewing end time is the viewing data for the most recently viewed content. Next, in step S502, the viewing data acquisition unit 103 reads the viewing data of other previously viewed content from the viewing data storage unit 4. Among the viewing data stored in the viewing data storage unit 4, the viewing data of content other than the most recently viewed content is the data for previously viewed content acquired in this step.

[0073] The next steps, from S503 to S505, are a repetitive process (first loop). This first loop is repeated as long as there are unprocessed related content, directly or indirectly, starting from the most recently viewed content acquired in step S501. In step S504 within the first loop, the content search unit 104 performs a search and acquires information on one unprocessed related content from the metadata storage unit 101. During this search process, the content search unit 104 acquires information on the relationships between content (for example, pairs of base words and advanced words held by the relationship data storage unit 102). The content search unit 104 also acquires information such as the URL of the content from the metadata storage unit 101. The display unit 105 then generates an overall display screen using the information on the one content acquired by the content search unit 104. That is, the display unit 105 adds information corresponding to that one content (a node corresponding to that content, and an edge representing the connection to that content) to the graph on the overall display screen. The next step, S505, marks the end of the first loop. If the conditions for repeating the first loop are met, i.e., if there is unprocessed related content, the first loop is repeated to process the next unprocessed related content. If the conditions for repeating the first loop are not met, i.e., if there is no more unprocessed related content, the first loop is exited and the process moves to the next step, S506.

[0074] In other words, the content search unit 104 reads related terms that are paired with the terms contained in the metadata for the first content from the relationship data storage unit. The content search unit 104 determines related content that contains the related terms as metadata by referring to the metadata storage unit 101. Furthermore, the content search unit 104 recursively determines further related content using the determined related content as the first content. The recursion here corresponds to the iterative processing in the first loop described above.

[0075] The next steps, from S506 to S508, are a repetitive process (second loop). This second loop is repeated as long as there are unprocessed related content items up to M steps (stages) ahead, starting from the most recently viewed content acquired in step S501. M is a non-negative integer set as appropriate. For example, M=2. The number of steps here refers to the number of stages in the relationship between the content items. The set of related content items up to M steps ahead is a subset of the set of related content items whose data was acquired in step S504 within the first loop. In step S507 within the second loop, the display unit 105 creates an enlarged screen for one of the unprocessed related content items up to M steps (stages) ahead, starting from the most recently viewed content, based on the data of that related content held by the metadata storage unit 101. That is, the display unit 105 adds information corresponding to that one piece of content (the node corresponding to that content, and the edge representing the connection to that content) to the graph in the enlarged display screen. Furthermore, the display unit 105 adds other information that may be displayed within the enlarged display screen (information about words that represent the relationships between content, for example, basic words and advanced words). The next step, S508, marks the end of the second loop. If the repeat condition of the second loop is met, that is, if there is unprocessed related content within the range up to step M described above, the processing of the second loop is repeated to process the next unprocessed related content. If the repeat condition of the second loop is not met, that is, if there is no more unprocessed related content, the second loop is exited and the process moves to the next step, S509 (Figure 8).

[0076] In other words, in the second loop as well, the content search unit 104 reads related terms that are paired with the terms contained in the metadata for the first content from the relationship data storage unit. The content search unit 104 determines related content that contains the related terms as metadata by referring to the metadata storage unit 101. Furthermore, the content search unit 104 recursively determines further related content using the determined related content as the first content. That is, the recursion here corresponds to the iterative processing in the second loop described above.

[0077] The overall display screen generated in the first loop (steps S503 to S505) and the enlarged display screen generated in the second loop (steps S506 to S508) will be switched and displayed on the screen as appropriate during the following processes.

[0078] Next, moving to Figure 8, steps S509 to S518 constitute a repetitive process (third loop). This third loop process is repeated as long as the user has not yet selected the content to be viewed (played) on the displayed screen (full view screen or enlarged view screen). While the processing within this third loop is running, the user can, for example, click on a node in the graph on the screen as an operation to view content. When a node in the graph is clicked, the operation unit 106 passes the URL information of the content corresponding to the clicked node to the playback control unit 3. As a result, the playback control unit 3 requests the distribution server device 7 to distribute the content based on that URL. The processing within the third loop is as follows.

[0079] In step S510, the display unit 105 determines whether the current state is the enlarged display state. At any given time, the display state of the content presentation device 1 is either the full display state (the state in which the display shown as illustrated in Figure 4) or the enlarged display state (the state in which the display shown as illustrated in Figures 5 and 6). The user switches to one of the above display states by selecting the enlarged display button 221 or the full display button 222. If the display state is enlarged at that time (step S510: YES), the process proceeds to the next step S511. If the display state is not enlarged (step S510: NO), i.e., the display state is full display, the process branches and proceeds to step S513.

[0080] If the process proceeds to step S511 (magnified display state), in this step, the display unit 105 displays the magnified screen on the screen of the receiving device 10. The magnified screen is the screen created in the processing of the second loop above. Next, in step S512, the display unit 105 displays the overall screen in a reduced state on the screen of the receiving device 10. The overall screen is the screen generated in the processing of the first loop above. In other words, in the magnified display state, the display unit 105 displays both the reduced overall screen and the magnified screen. An example of the display in the magnified display state is as explained with reference to Figure 5, etc. Next, the process proceeds to step S514.

[0081] If the process proceeds to step S513 (overall display state), in this step, the display unit 105 displays the overall screen on the screen of the receiving device 10. An example of the display in the overall display state is as described with reference to Figure 4. Next, the process proceeds to step S514.

[0082] Next, in step S514, the display unit 105 displays an indication that the node corresponding to the most recently viewed content among the nodes of the graph displayed on the screen is the most recently viewed content (display of the most recently viewed mark). Examples of methods for indicating that it is the most recently viewed content include making the outline of the shape representing the node thicker, or making the color or fill pattern of the shape different from other nodes. However, it is also possible to indicate that it is the most recently viewed content by display methods other than those exemplified here.

[0083] Next, in step S515, the display unit 105 displays information indicating that the content has been viewed (display of a viewed mark). An example of a method for indicating that the content has been viewed is to add a mark containing the words "viewed" to the node corresponding to that content. However, content may also be indicated as viewed by a display method other than the one exemplified here.

[0084] Next, in step S516, the operation unit 106 determines whether the user has performed an operation to select an edge in the graph. An operation to select an edge is, for example, touching the location of the edge on a screen with a touch panel, or clicking the location of the edge on the screen with a mouse. If an edge is selected (step S516: YES), the process proceeds to the next step S517. If no edge is selected (step S516: NO), the process jumps to step S518. Note that the operation to select an edge is performed by the user in order to refer to the relationship (relationship between content) corresponding to that edge.

[0085] If the process proceeds to step S517 as a result of the above determination, in that step, the display unit 105 displays a phrase (word pair) that represents the relationship indicated by the edge whose selection was confirmed in that step, near that edge. In other words, in this step, the display unit 105 displays words that form the basis of the connection between nodes (between contents). Examples of phrases displayed by the display unit 105 here are phrases 241 and 242 illustrated in Figure 6. Once the display of phrases is complete, the process moves to step S518.

[0086] The next step, S518, marks the end of the third loop. If the repeat condition for the third loop is met, that is, if the user has not yet selected the next content to play, the processing of the third loop from step S510 is repeated. If the repeat condition for the third loop is not met, that is, if the user has selected the next content to play, the third loop is exited and the processing of the entire flowchart ends. As mentioned above, when the user selects content (node), the operation unit 106 instructs the playback control unit 3 to play the selected content. This allows the user to then view the selected content.

[0087] [First variation] Modifications of the first embodiment may also be implemented. In the first embodiment described above, the relationship data storage unit 102 stored only one type of relationship (the basic development relationship exemplified in Figure 2). As a modification, the relationship data storage unit 102 may store information on multiple types of relationships. For example, the relationship data storage unit 102 may store data on three types of relationships: (1) basic development relationships, (2) hierarchical relationships, and (3) temporal relationships. The basic development relationship exemplified here is a relationship represented by a correspondence between a basic word and a developed word (a pair of words). A hierarchical relationship is a relationship represented by a correspondence between a superordinate conceptual word and a subordinate conceptual word (a pair of words). A temporal relationship is a relationship represented by a correspondence between a word that relatively belongs to the past and a word that relatively belongs to the future (a pair of words). The relationship data storage unit 102 may also store information on any number of other types of relationships besides those exemplified above.

[0088] If the relationship data storage unit 102 has information on multiple types of relationships, the display unit 105 may simultaneously display graphs representing these multiple relationships (for example, changing the display attributes (color, etc.) of the edges for each type of relationship) on the screen. Alternatively, in that case, the display unit 105 may display only the graph representing a specific relationship selected by the user or the like from among the multiple types of relationships on the screen.

[0089] [Second variation] As a further modification of the first embodiment, various information may also be displayed on the overall display screen (Figure 4). For example, the display unit 105 may display information on the overall display screen indicating whether each piece of content has been viewed or whether it is recently viewed. The display unit 105 may also display on the overall display screen words that indicate the type of relationship (e.g., basic-development relationship) and direction (e.g., words such as "basic" and "development" as explained in Figures 5 and 6). The display unit 105 may also display on the overall display screen words that are individually associated with each edge in the graph (e.g., words 241 ("atmosphere") and words 242 ("carbon dioxide") as explained in Figure 6).

[0090] [Third variation] As a further modification of the first embodiment, the following may be made. In the first embodiment, based on the viewing end date and time value in the viewing data (exemplified in Figure 3), the content with the largest (most recent) viewing end date and time value was treated as the most recently viewed content. As a modification, a region for storing the URL (content identification information) of the most recently viewed content may be provided in the viewing data, and the playback control unit 3 may update this region each time viewing of new content is started.

[0091] As described above, according to this embodiment (including modifications), the content presentation device 1 presents content in a manner that allows the user to easily select the next content to view. Specifically, the content presentation device 1 of this embodiment can present information such as the relationships between content and viewing history using a graphical user interface. In addition, the content presentation device 1 can display terms that represent the connections between content (for example, basic terms and advanced terms).

[0092] [Second Embodiment] Next, a second embodiment will be described. Note that some matters already explained in the previous embodiment may be omitted below. Here, we will focus on matters specific to this embodiment.

[0093] In the first embodiment described above, the content search unit 104 searched for related content based on the relationship data (e.g., basic development relationship data) stored in the relationship data storage unit 102. In the first embodiment, the content presentation device 1 imported relationship data from, for example, another device and wrote it to the relationship data storage unit 102. In contrast, in the second embodiment, the content presentation device 2 is equipped with a function for generating relationship data.

[0094] Figure 9 is a block diagram illustrating the schematic functional configuration of a content presentation system according to the second embodiment. As shown in the figure, the content presentation system 51 is composed of a distribution server device 7, the Internet 8, and a receiving device 11. The distribution server device 7 and the Internet 8 are as described in the first embodiment. The receiving device 11 is a device that receives and plays content (video content) and presents it to the user, replacing the receiving device 10 in the first embodiment. The receiving device 11 is composed of a playback control unit 3, a viewing data storage unit 4, and a content presentation device 2. The playback control unit 3 and the viewing data storage unit 4 have already been described in the first embodiment. In other words, the receiving device 11 of this embodiment includes a content presentation device 2 instead of the content presentation device 1 in the first embodiment. That is, the receiving device 11 includes the content presentation device 2 internally and can present content (referred to as related content) related to a certain content (for example, content viewed by the user) to the user.

[0095] As shown in Figure 9, the functional configuration of the content presentation device 2 is as follows. Specifically, the content presentation device 2 is composed of a metadata storage unit 101, a relationship data storage unit 102, a viewing data acquisition unit 103, a content search unit 104, a display unit 105, an operation unit 106, and a relationship extraction device 109. Of this configuration, the metadata storage unit 101, the relationship data storage unit 102, the viewing data acquisition unit 103, the content search unit 104, the display unit 105, and the operation unit 106 are as described in the first embodiment. In other words, a feature of the content presentation device 2 of this embodiment is the inclusion of a relationship extraction device 109.

[0096] The relationship extraction device 109 extracts pairs of concepts (phrases) having a predetermined relationship based on multiple (numerous) document data provided from an external source as appropriate, and writes that information to the relationship data storage unit 102. In other words, the relationship extraction device 109 extracts relationship data representing the relationships between phrases based on document data and writes the extracted relationship data to the relationship data storage unit 102. That is, the relationship extraction device 109 generates relationship data based on document data. Note that the above-mentioned "pairs of concepts" are specifically represented as pairs of phrases. The specific method by which the relationship extraction device 109 extracts relationships between phrases will be explained below.

[0097] The relationship extraction device 109 of this embodiment extracts the relationships between words and phrases that appear in the document data, based on the document data.

[0098] Specifically, the relationships between words extracted by the relationship extraction device 109 of this embodiment are basic-development relationships. Basic-development relationships represent the relationship between basic concepts (words) and advanced concepts (words). As explained in the first embodiment, related content corresponding to specific content (main content) can be searched based on basic-development relationships. Here, the document data used by the relationship extraction device 109 has a structure consisting of pairs of title data and body data. Also, the document data is typically data from a teaching material document. When extracting basic-development relationships, the basic structure of teaching materials is utilized, where, when the document data consists of pairs of title and body, "newly learned words (terms) exist in the title and are explained by words (terms) that appear in the body." In other words, the relationship extraction device 109 extracts basic-development relationships between words by estimating important words included in the title as advanced words and important words not included in the title as basic words among the important words in the document data of the teaching material. In other words, basic-development relationships correspond to the relationship of learning order among multiple teaching material documents.

[0099] In this description of the embodiment, "words" refers to words, idioms, and phrases (such as noun phrases). The processing related to words in this embodiment may be replaced with processing related to idioms and phrases.

[0100] The relationship extraction device 109 in this embodiment automatically extracts relationships between words corresponding to the learning order from a document. These relationships are those between basic words and advanced words. In other words, in this embodiment, for example, word pairs in a basic-advanced relationship are automatically extracted from teaching materials such as textbooks and supplementary materials for educational content.

[0101] Figure 10 is a block diagram illustrating the schematic functional configuration of the relation extraction device 109. As shown in the figure, the relation extraction device 109 is composed of a basic development relation extraction unit 1091 and a structuring unit 1092. As explained in the first embodiment, each function of the relation extraction device 109 can be realized, for example, by a computer and a program. Each functional unit also has storage means as needed. If necessary, non-volatile storage means such as a magnetic hard disk drive or a solid-state drive (SSD) may be used. Furthermore, at least some of the functions of each functional unit may be realized as a dedicated electronic circuit instead of a program.

[0102] The relationship extraction device 109 extracts relationships between concepts based on the input document data and stores the relationship information in the relationship data storage unit 102. In other words, the relationships between concepts are the relationships between words. Furthermore, the relationships between concepts extracted by the relationship extraction device 109 are "basic development relationships." "Basic development relationships" will be explained further later.

[0103] The functions of each part within the relation extraction device 109 are as follows.

[0104] The basic development relationship extraction unit 1091 acquires document data and extracts relationships between concepts based on that document data. Specifically, the basic development relationship extraction unit 1091 extracts basic development relationships between concepts and outputs a basic development relationship list, which is data representing those relationships. The basic development relationship extraction unit 1091 passes the generated basic development relationship list to the structuring unit 1092. A more detailed explanation of the basic development relationship extraction unit 1091's functional configuration will be provided later with reference to Figure 11.

[0105] The structuring unit 1092 generates structured data based on the list of basic development relationships output by the basic development relationship extraction unit 1091. This structured data represents the basic development relationships between concepts (between words) and is expressed, for example, in RDF format. RDF stands for "Resource Description Framework". Data in RDF format is also suitable for representing directed graphs, and the list of basic development relationships output by the basic development relationship extraction unit 1091 is equivalent to a set of such directed graphs. The structuring unit 1092 then writes the generated structured data to the relationship data storage unit 102.

[0106] An example of structured data generated by the structuring unit 1092 is as follows: When the word "distributive law" is used as the base word, one of its derived words is "factorization." Also, when the word "factorization" is used as the base word, its derived words are "cross multiplication" and "quadratic equation." The structured data generated by the structuring unit 1092 can represent any number of correspondences between base words and derived words, not limited to the example given here. In other words, the structured data (RDF data) generated by the structuring unit 1092 systematizes the base development relationships between many words.

[0107] The relationship data storage unit 102 stores the structured data generated by the structuring unit 1092. In other words, the relationship data storage unit 102 holds information about the basic and developmental relationships between words. The relationship data storage unit 102 may also be called the "basic and developmental relationship data storage unit." In other words, the relationship data storage unit 102 stores the basic and developmental relationships extracted by the basic and developmental relationship extraction unit 1091.

[0108] Figure 11 is a block diagram showing a more detailed functional configuration of the basic development relationship extraction unit 1091. As shown in the figure, the basic development relationship extraction unit 1091 includes a document acquisition unit 1094, a document conversion unit 1095, an important word extraction unit 1096, a basic development relationship estimation unit 1097, and a basic development relationship list output unit 1098.

[0109] The document acquisition unit 1094 acquires document data from an external source. The document data is educational data (teaching material data) and includes a title and body text. The teaching material data consists of multiple sections (units, etc.), and each section has a pair of titles and body texts. The document acquisition unit 1094 passes the pair of titles and body texts as one document data item to the document conversion unit 1095. In other words, the data acquired by the document acquisition unit 1094 from an external source includes multiple document data items. These multiple document data items included in one set of document data are pre-ordered. This order may correspond to, for example, the page order in a textbook. Alternatively, this order may correspond to, for example, the broadcast order of broadcast content. Alternatively, this order may correspond to, for example, the presentation order of content presented on the web.

[0110] An example of a single document data (i.e., a pair of title and body text) will be explained later, referring to Figures 12 and 13.

[0111] The document conversion unit 1095 performs a process to generate a composite sentence, which is data that concatenates the title and the body, based on the document data, which includes the title and the body. Specifically, the document conversion unit 1095 performs a conversion process on the document data passed from the document acquisition unit 1094. The data before the conversion process is, as described above, the title and body data passed from the document acquisition unit 1094. The data after the conversion process by the document conversion unit 1095 is the title and composite sentence data. Here, the composite sentence is data that concatenates the title and the body. Note that the title, body, and composite sentence are each text (a sequence of characters) data. The document conversion unit 1095 passes the converted data (i.e., the title and composite sentence pair) to the important word extraction unit 1096. The conversion process by the document conversion unit 1095 will be explained further later with reference to Figure 14.

[0112] The important word extraction unit 1096 extracts important words from at least one of the words contained in the title and the body of the document, based on the document data which includes the title and the body of the document. The important word extraction unit 1096 may extract the important words for each document data, based on multiple document data which each include the title and the body of the document. The important word extraction unit 1096 may extract important words by performing an analysis process on the synthesized sentence.

[0113] In this embodiment, specifically, the important word extraction unit 1096 receives the data after the above conversion process (pairs of title and composite sentence) from the document conversion unit 1095 and extracts important words from the title and the composite sentence, respectively. Specifically, the important word extraction unit 1096 extracts nouns (which may include noun phrases; the same applies hereinafter) from the title and the composite sentence by performing morphological analysis or the like. Existing technologies can be used for the process of extracting nouns. The important word extraction unit 1096 also extracts important words from the nouns extracted from the composite sentence. At this time, values ​​such as TF-IDF can be used as the importance of the nouns. TF-IDF is a value calculated as the product of the TF (term frequency) value and the IDF (inverse document frequency) value. TF is a numerical value that represents how often a certain word appears in a given document. IDF is a numerical value that represents how rarely documents containing a certain word exist among all documents. Here, "all documents" includes not only the title-to-compound sentence pair in question, but also other title-to-compound sentence pairs. In other words, the important word extraction unit 1096 calculates a TF-IDF value for each noun extracted from the compound sentence, and extracts nouns in a predetermined range (for example, a predetermined number) with high TF-IDF values ​​as important words. The important word extraction unit 1096 passes the information of the extracted important words, along with the data of the title-to-compound sentence pair, to the basic development relationship estimation unit 1097.

[0114] The basic-development relationship estimation unit 1097 estimates pairs of words that have a specific relationship based on the data passed from the important word extraction unit 1096. A specific relationship is, for example, a basic-development relationship. A basic-development relationship is as follows: When the concept represented by word A is the basis of the concept represented by word B, then word A is the basis of word B. Furthermore, when word A is the basis of word B, word B is always an evolution of word A.

[0115] The basic-development relationship estimation unit 1097 determines, as development words, important words selected from the important words extracted by the important word extraction unit 1096, on the condition that they are included in the title, and determines, as basic words, important words that were not selected as development words, and extracts pairs of the determined basic words and determined development words as basic-development relationships. The multiple document data to be processed by the basic-development relationship estimation unit 1097 may be ordered. In this case, the basic-development relationship estimation unit 1097 may determine, as development words, important words selected from the important words extracted by the important word extraction unit 1096, on the condition that the words included in the title are newly appearing words based on the order of the document data. The procedure for determining whether or not an important word included in the title is a newly appearing word will be explained later with reference to the flowchart in Figure 18.

[0116] The method by which the Basic-Development Relationship Estimation Unit 1097 estimates the basic-development relationship is as follows: Among the important words extracted by the important word extraction unit 1096, newly introduced important words included in the title are development words, and the other important words are basic words. The Basic-Development Relationship Estimation Unit 1097 estimates the pairs of basic words and development words determined in this way as the basic-development relationship. In other words, the pair of basic words and development words is a word-phrase pair that represents the basic-development relationship.

[0117] The Basic and Advanced Relationship Estimation Unit 1097 determines whether a given important word is new or has appeared before based on its order in the set of document data (the group of teaching material documents). For example, in high school mathematics teaching materials, the item "Linear Inequalities" is followed by the item "Various Linear Inequalities." Then, in the text of the item "Various Linear Inequalities," advanced content such as "Systems of Linear Inequalities" may be explained. The order of appearance in the teaching materials matches the order of the document data passed to the Basic and Advanced Relationship Extraction Unit 1091. In this way, by determining whether an important word is new or has appeared before based on a predetermined order of document data (the determination in step S007 of Figure 18, which will be described later), it becomes possible to eliminate reversed pairs of words in the basic and advanced relationship.

[0118] The basic development relationship list output unit 1098 generates a basic development relationship list, which is a list of word pairs output by the basic development relationship estimation unit 1097, and passes it to the structuring unit 1092. In other words, the basic development relationship list output unit 1098 outputs the basic development relationship list as information representing the estimation results of relationships between concepts. The data that constitutes the basic development relationship list will be explained later with reference to Figures 16 and 17.

[0119] Next, with reference to Figures 12 and 13, we will describe examples of document data that the relationship extraction device 109 processes. In other words, Figures 12 and 13 each show examples of data used as information for extracting basic and developmental relationships.

[0120] Figure 12 is a schematic diagram showing an example of a single document data item acquired by the document acquisition unit 1094 of the basic development relationship extraction unit 1091. This single document data item includes a pair of title data and body data. As shown in the figure, in this example, the title is "Linear Equations". The body text corresponding to this title is "Reviewing the methods for solving linear equations. In order to reliably solve linear equations, ... (omitted)". In other words, this document data corresponds to a section of a mathematics textbook.

[0121] Figure 13 is a schematic diagram showing another example of a single document data item acquired by the document acquisition unit 1094 of the basic development relationship extraction unit 1091. This single document data item includes a pair of title data and body data. As shown in the figure, in this example, the title is "Considering the Relationship Between Force and Motion ~ The Law of Inertia". The body text corresponding to this title is "When no force acts on an object, or when forces act on it but those forces are in equilibrium, a stationary object remains stationary... (omitted)". In other words, this document data corresponds to a section of a physics textbook.

[0122] Figure 14 is a schematic diagram showing the processing by the document conversion unit 1095 (document conversion processing) and the relationship between its input and output data. As shown in the figure, the data input to the document conversion unit 1095 is the document data 301 before conversion. The document data 301 before conversion is a series of multiple document data 302. The document data 302 have an overall order. Each document data 302 contains a pair of title 303 and body text 304. On the other hand, the data output from the document conversion unit 1095 is the document data 401 after conversion. The document data 401 after conversion is a series of multiple document data 402. The document data 402 corresponds to the input document data 302 and inherits the order (overall order) of the input document data 302. Each document data 402 contains a pair of title 403 and composite text 405. The data of the composite text 405 is data obtained by concatenating the title 303 and body text 304 from the input. Note that the data for title 403 is identical to the data for title 303 on the input side.

[0123] In other words, as shown in Figure 14, the document conversion unit 1095 generates a composite text 405 based on individual document data 302 by concatenating the title 303 and body text 304 of each document data 302. The document data 402 (after conversion) output by the document conversion unit 1095 has pairs of title 403 and composite text 405.

[0124] Figure 15 is a schematic diagram showing an example of document data converted by the document conversion unit 1095. The converted document data shown in Figure 15 is data obtained by converting from the original document data explained in Figure 12. As mentioned above, a composite sentence is data that concatenates the title and the body text. In the data exemplified in Figure 15, the first part of the composite sentence, "linear equation," is the title data. The part that follows in the composite sentence, "Let's review the solution method for linear equations... (omitted)," is the body text data.

[0125] Next, we will explain the data in the basic-development relationship list, referring to Figures 16 and 17. As shown in Figures 16 and 17, the basic-development relationship list is tabular data that represents the correspondence between basic words and advanced words.

[0126] Figure 16 is a schematic diagram showing an example of a basic-development relationship list generated and output by the basic-development relationship list output unit 1098. The basic-development relationship list in Figure 16 was generated based on the document data exemplified in Figure 12. The basic-development relationship list in Figure 16 has five pairs of basic words and development words. In all five pairs, the development word is "linear equation". This development word was determined as a development word by the basic-development relationship estimation unit 1097 from the title "linear equation" in the document data shown in Figure 12. On the other hand, in these five pairs, the basic words are "equation", "both sides", "transposition", "left side", and "right side", respectively. These basic words are important words extracted from the text of the document data shown in Figure 12 and were determined as basic words by the basic-development relationship estimation unit 1097.

[0127] Figure 17 is a schematic diagram showing another example of a basic-development relationship list generated and output by the basic-development relationship list output unit 1098. The basic-development relationship list in Figure 17 was generated based on the document data exemplified in Figure 13. The basic-development relationship list in Figure 17 has five pairs of basic words and developed words. In all five pairs, the developed word is "law of inertia." This developed word is an important word extracted from the title "Considering the Relationship Between Force and Motion ~ Law of Inertia" in the document data shown in Figure 13, and was determined as a developed word by the basic-development relationship estimation unit 1097. On the other hand, in these five pairs, the basic words are "force," "motion," "object," "uniform linear motion," and "velocity." Of these five basic words, three—"object," "uniform linear motion," and "velocity"—are important words extracted from the main text of the document data shown in Figure 13. Also, two—"force" and "motion"—are important words extracted from the title of the document data shown in Figure 13. However, the two words "force" and "motion" are not new important words in the document data (Figure 13), but rather important words that have already appeared in other document data. Even if an important word is extracted from the title, if it is a word that has appeared before, it is determined to be a basic word rather than a development word (see also the flowchart in Figure 18, which will be explained later). These five basic words are words that were determined to be basic words by the basic-development relationship estimation unit 1097.

[0128] Figure 18 is a flowchart showing the procedure for the extraction of basic and developmental relationships by the basic and developmental relationship extraction unit 1091. The following describes the process of extracting basic and developmental relationships according to this flowchart. Note that this flowchart shows the process corresponding to one document data (a pair of title and body text). When multiple document data exist, they are ordered as described above, and the process in this flowchart is executed for each document data according to that order.

[0129] In step S001, the document acquisition unit 1094 acquires one document data. As mentioned above, the document data acquired by the document acquisition unit 1094 is educational material data and includes pairs of title and body data.

[0130] In step S002, the document conversion unit 1095 performs a process to convert the document data input in step S001. As a result of this conversion process, composite sentence data is generated. As mentioned above, the composite sentence data is data that concatenates the title and the body text.

[0131] In step S003, the important word extraction unit 1096 extracts important words. Important words are extracted from both the title and the synthesized sentence. Important words may be nouns or noun phrases. The importance of a word may be determined by, for example, the TF-IDF value, as described above. The important word extraction unit 1096 extracts words with relatively high importance as important words.

[0132] In step S004, the basic development relationship estimation unit 1097 determines whether or not important words (extracted in step S003) are present in the title. If important words are present in the title (step S004: YES), the process proceeds to the next step S005. If important words are not present in the title (step S004: NO), the processing for that pair (title and body text pair) is terminated.

[0133] Step S005 marks the start of a loop. The end of this loop is in step S010 below. The condition for executing the process in between (steps S006 to S009) is that there are undecided important words among the important words extracted in step S003. In other words, this loop is executed for each important word until there are no more undecided important words among the important words extracted from the compound sentence.

[0134] In step S006, the basic development relationship estimation unit 1097 determines whether or not a particular important word is included in the title. If the important word is included in the title (step S006: YES), the process proceeds to the next step S007. If the important word is not included in the title (step S006: NO), the process jumps to step S009.

[0135] If the process proceeds to step S007, the basic development relationship estimation unit 1097 determines whether the important word is a new important word or not. The title-to-compound sentence pair is generated based on the title-to-body text pair. As mentioned above, the title-to-body text pair is ordered. When processing the title-to-body text pair according to that order, if the important word currently being processed has not appeared in a previous title, then that important word is new. If the important word currently being processed has appeared in a previous title, then that important word is not new (it has appeared before). Note that when determining whether the important word currently being processed is new or has appeared before, instead of using whether it appeared in a previous title as the criterion, the criterion may be whether it appeared in either a previous title or the body text. If the important word currently being processed is new (step S007: YES), the process proceeds to step S008. If the important word currently being processed is not new, i.e., it has appeared before (step S007: NO), the process proceeds to step S009.

[0136] If the process proceeds to step S008 (from step S007), the basic development relationship estimation unit 1097 extracts the important words currently being processed as development words. After processing in this step, the process proceeds to step S010.

[0137] If the process proceeds to step S009 (from step S006 or S007), the basic development relationship estimation unit 1097 extracts the important words currently being processed as basic words. After processing in this step, the process proceeds to step S010.

[0138] As described above, in the processing from steps S006 to S009, the basic-development relationship estimation unit 1097 determines whether the important word being processed is a development word or a basic word.

[0139] Step S010 is the endpoint of the loop, as mentioned above. From step S010, we return to step S005 to process the next important word (the important word extracted from the compound sentence).

[0140] Once the processing from steps S005 to S010 (repeating for each important word) is complete, the process moves on to step S011.

[0141] In step S011, the basic-development relationship list output unit 1098 creates and outputs a list representing basic-development relationships. The basic-development relationship list is data from a list representing a set of pairs of basic words and developed words. The basic-development relationship list contains pairs of basic words and developed words, which are extracted as basic words (as described in step S009) and words extracted as developed words (as described in step S008) based on a given title-text pair. Based on a title-text pair, zero, one, or more pairs of basic words and developed words may be generated. When the processing in step S011 is completed, the basic-development relationship extraction unit 1091 completes the entire processing for that document data.

[0142] [Differentiation] A modification of the second embodiment may also be implemented. In the second embodiment, the basic development relationship extraction unit 1091 selected important terms from among the important terms extracted by the important term extraction unit 1096 as development terms, on the condition that the terms included in the title were newly appearing terms based on the order of the document data. As a modification, important terms included in the title may be determined as development terms regardless of whether or not they are newly appearing important terms.

[0143] As described above, according to this embodiment (including modified versions), the relationship extraction device 109 can extract word pairs having predetermined relationships, such as basic and advanced relationships, based on document data representing the content of, for example, textbooks or supplementary materials for educational content. A word pair represents the relationship between words (concepts). In other words, the content search unit 104 can search for related content related to a specific content (such as recently viewed content) based on the relationship data obtained by the relationship extraction device 109. That is, it becomes possible to automatically generate relationship data based on existing document data.

[0144] Examples of the internal configurations of each device described in the first and second embodiments are described below.

[0145] Figure 19 is a block diagram showing an example of the internal configuration of a device for realizing at least some of the functions of the receiving device 10 or the receiving device 11. The device can be realized using a computer. As shown in the figure, the computer consists of a central processing unit 901, RAM 902, input / output ports 903, input / output devices 904 and 905, etc., and a bus 906. The computer itself can be realized using existing technology. The central processing unit 901 executes instructions contained in programs read from RAM 902, etc. The central processing unit 901 writes data to RAM 902, reads data from RAM 902, and performs arithmetic and logical operations according to each instruction. RAM 902 stores data and programs. Each element contained in RAM 902 has an address and can be accessed using that address. RAM stands for "Random Access Memory". Input / output ports 903 are ports for the central processing unit 901 to exchange data with external input / output devices, etc. Input / output devices 904 and 905 are input / output devices. Input / output devices 904 and 905 exchange data with the central processing unit 901 via input / output port 903. Bus 906 is a common communication channel used within the computer. For example, the central processing unit 901 reads and writes data to RAM 902 via bus 906. Also, for example, the central processing unit 901 accesses input / output ports via bus 906.

[0146] At least some of the functions of the receiving device (including its internal components) and the distribution server device in the above-described embodiments (including modified versions) can be realized by a computer and a program. In this case, the program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be loaded into a computer system and executed. Here, "computer system" includes hardware such as the OS and peripheral devices. Furthermore, "computer-readable recording medium" refers to portable media such as flexible disks, magneto-optical disks, ROMs, CD-ROMs, DVD-ROMs, USB memory, and storage devices such as hard disks built into a computer system. In other words, "computer-readable recording medium" may be a non-transitory computer-readable recording medium. Moreover, "computer-readable recording medium" may also include those that temporarily and dynamically hold programs, such as communication lines when transmitting programs via networks such as the Internet or communication lines such as telephone lines, and those that hold programs for a certain period of time, such as volatile memory inside a computer system that acts as a server or client in such a case. Furthermore, the above program may be intended to implement only a part of the functions described above, or it may be possible to implement the above functions in combination with programs already recorded in the computer system.

[0147] While embodiments and modifications of this invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and includes designs and the like that do not depart from the spirit of this invention. [Industrial applicability]

[0148] The present invention can be used, for example, in content distribution businesses and educational businesses to process related content associated with specific content. However, the scope of use of the present invention is not limited to those exemplified herein. [Explanation of Symbols]

[0149] 1. Content display device 3. Regeneration Control Unit 4. Viewing data storage unit 7 Distribution Server Device 8. Internet 10 Receiving device 50 Content Presentation Systems 101 Metadata storage unit 102 Relationship data storage unit 103 Viewing Data Acquisition Unit 104 Content Search Department 105 Display section 106 Operation section 109 Relational Extraction Device 201 Nodes (Nodes representing recently viewed content) 202 nodes (nodes representing related content) 221 Enlarge button 222 Full View Button 231 Full view screen shown in a reduced size 232 Enlarged View Range 241 vocabulary words (basic words) 242 words (vocabulary, advanced vocabulary) 901 Central Processing Unit 902 RAM 903 Input / Output Ports 904,905 Input / Output Devices 906 Bus 1091 Extraction section of basic development-related information 1092 Structuring part 1094 Document Acquisition Department 1095 Document Conversion Department 1096 Important word extraction part 1097 Estimation of Basic Development Relationships 1098 Basic Development Relationship List Output Section

Claims

1. A relationship data storage unit that stores a set of pairs of words having a specific relationship as relationship data, A metadata storage unit stores metadata for each piece of content, which includes information about words or phrases that represent the content. A content search unit reads related terms that are paired with the terms contained in the metadata relating to the first content from the relationship data storage unit, determines related content that includes the related terms as metadata by referring to the metadata storage unit, and further determines further related content by recursively using the determined related content as the first content. A display unit that displays information on content determined by the content search unit to be related content directly or indirectly related to the most recently viewed content, based on the most recently viewed content, A viewing data acquisition unit acquires viewing data that includes viewing history information about the content that has been viewed, Equipped with, The display unit displays information on the most recently viewed content and related content that is directly or indirectly related to the most recently viewed content in the form of a graph, where the first content and the related content are represented as nodes, and the relationship between the first content and the related content directly related to the first content is represented as an edge. The display unit displays the graph by marking nodes corresponding to content included in the viewing data with a "viewed" mark. Content display device.

2. A relationship data storage unit that stores a set of pairs of words having a specific relationship as relationship data, A metadata storage unit stores metadata for each piece of content, which includes information about words or phrases that represent the content. A content search unit reads related terms that are paired with the terms contained in the metadata relating to the first content from the relationship data storage unit, determines related content that includes the related terms as metadata by referring to the metadata storage unit, and further determines further related content by recursively using the determined related content as the first content. A display unit that displays information on content determined by the content search unit to be related content directly or indirectly related to the most recently viewed content, based on the most recently viewed content, Equipped with, The display unit displays information on the most recently viewed content and related content that is directly or indirectly related to the most recently viewed content in the form of a graph, where the first content and the related content are represented as nodes, and the relationship between the first content and the related content directly related to the first content is represented as an edge. When instructed to display an enlarged view, the display unit enlarges only graphs where the distance between the number of relationship levels between nodes is M or less (where M is a non-negative integer set as appropriate), starting from a specific piece of content. Content display device.

3. A relationship data storage unit that stores a set of pairs of words having a specific relationship as relationship data, A metadata storage unit stores metadata for each piece of content, which includes information about words or phrases that represent the content. A content search unit reads related terms that are paired with the terms contained in the metadata relating to the first content from the relationship data storage unit, determines related content that includes the related terms as metadata by referring to the metadata storage unit, and further determines further related content by recursively using the determined related content as the first content. A display unit that displays information on content determined by the content search unit to be related content directly or indirectly related to the most recently viewed content, based on the most recently viewed content, Equipped with, The display unit displays information on the most recently viewed content and related content that is directly or indirectly related to the most recently viewed content in the form of a graph, where the first content and the related content are represented as nodes, and the relationship between the first content and the related content directly related to the first content is represented as an edge. The system further includes an operating unit that accepts user operations for selecting a specific edge, The display unit displays a pair of words associated with the edge selected by the operation unit. Content display device.

4. A relationship data storage unit that stores a set of pairs of words having a specific relationship as relationship data, A metadata storage unit stores metadata for each piece of content, which includes information about words or phrases that represent the content. A content search unit reads related terms that are paired with the terms contained in the metadata relating to the first content from the relationship data storage unit, determines related content that includes the related terms as metadata by referring to the metadata storage unit, and further determines further related content by recursively using the determined related content as the first content. A display unit that displays information on content determined by the content search unit to be related content directly or indirectly related to the most recently viewed content, based on the most recently viewed content, Equipped with, The relationship data storage unit stores a set of pairs of words that have a foundation-development relationship between a word or phrase corresponding to "foundation" and a word or phrase corresponding to "development" as the relationship data. When the metadata for the first content contains multiple terms, the content search unit refers to the relationship data storage unit to select only the term corresponding to "development" from among those multiple terms, reads related terms that are paired with the term corresponding to "development" from the relationship data storage unit, and determines related content that includes the related terms as metadata by referring to the metadata storage unit. The display unit displays information on the most recently viewed content and related content that is directly or indirectly related to the most recently viewed content in the form of a graph, where the first content and the related content are represented as nodes, and the relationship between the first content and the related content directly related to the first content is represented as an edge. Content display device.

5. A relationship data storage unit that stores a set of pairs of words having a specific relationship as relationship data, A metadata storage unit stores metadata for each piece of content, which includes information about words or phrases that represent the content. A content search unit reads related terms that are paired with the terms contained in the metadata relating to the first content from the relationship data storage unit, determines related content that includes the related terms as metadata by referring to the metadata storage unit, and further determines further related content by recursively using the determined related content as the first content. A display unit that displays information on content determined by the content search unit to be related content directly or indirectly related to the most recently viewed content, based on the most recently viewed content, Equipped with, The display unit displays information on the most recently viewed content and related content that is directly or indirectly related to the most recently viewed content in the form of a graph, where the first content and the related content are represented as nodes, and the relationship between the first content and the related content directly related to the first content is represented as an edge. A relationship extraction device that extracts relationship data representing the relationships between words and phrases based on document data, and writes the extracted relationship data to the relationship data storage unit. Furthermore, The aforementioned relationship extraction device is A key word extraction unit extracts important words from at least one of the words contained in the title and the body of the document, based on document data including the title and the body of the document. The basic-development relationship extraction unit selects from the important words extracted by the important word extraction unit the important words that are included in the title as development words, determines the important words that were not selected as development words as basic words, and extracts pairs of the determined basic words and the determined development words as basic-development relationships. Equipped with, Content display device.

6. A program that causes a computer to function as a content presentation device according to any one of claims 1 to 5.

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