JP2005322025A - Device and method for converting structure description data into semantic description data - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform conversion into data after the conversion without lacking of information of a schema of data before the conversion, in the conversion between structure description data and semantic description data having different schema structures. <P>SOLUTION: In this schema part conversion device having a schema compatibility decision means, a schema element division means and a description system conversion means, used for a data conversion method converting the structure description data into the semantic description data, by dividing a schema of the structure description data into a schema of the semantic description data and a document and converting them, it is converted into the semantic description data without lacking of the information about the schema of the structure description data. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an apparatus and method for converting structure description data into semantic description data, and more particularly to an apparatus that converts metadata described in XML format into RDF format.

  Nowadays, with the spread of the Internet, users can search and obtain desired information by inputting keywords on the Web.

  However, as the number of Web pages increases, information unintended by the user is often presented by search, and the work efficiency is often lowered.

  Therefore, in order to improve the convenience of web page search and search efficiency, the W3C (World Wide Web Consortium) is studying the Semantic Web, and in the future, advanced semantic search and analogy search can be used on the Web. It is thought that it will become.

  RDF (Resource Description Framework), RDF Schema, and OWL (Web Ontology Language) capable of semantic description are adopted as a data format for realizing high-level semantic search on the Semantic Web. An RDF document describes certain information as a subject, a predicate, and an object and describes the relationship between elements in RDF and RDF Schema or OWL. It also makes it possible to realize analogical search.

  Therefore, in order to realize the above-described advanced semantic search and use more data, the data described in the XML format, which is the existing structure description data, is converted into the RDF format, which is the semantic description data, and used. It is possible.

  As a conventional data conversion method, as a method of converting between XML documents, when converting a document described in XML into another XML, an ontology is used to derive a difference or dependency between two XML Schemas. However, there is a method for converting an XML document (see, for example, Patent Document 1).

Further, as an example of a conversion method between different formats, there is a method of converting only an XML document into an RDF document from an XML document to an RDF document without considering the information of the XML Schema (for example, Non-Patent Document 1). checking).
JP 2003-233528 A Roger L. Costello, two others, “XML Design (A Gentle Transition from XML to RDF)” (4th page), [Online], The MITRE Corporation, [Search April 7, 2004], Internet <URL = http // www. cs. umbc. edu / 771 / current / presentations / RDF. ppt>

  However, the conversion method shown in Patent Document 1 is a method used for conversion between structure description data, which is conversion between different formats, that is, conversion from structure description data to semantic description data. There is a problem that it cannot be applied to conversion between formats having different schema structures. The method of Non-Patent Document 1 is an example of conversion between formats having different schema structures. However, the structure description data schema, for example, XML, is simply obtained by rewriting the structure description data document into the semantic structure data document. Since the information of Schema is not taken into account, there is a problem that all the information of the schema of the structure description data is lost at the time of conversion.

  For example, when the structure description data is XML data, the semantic description data is RDF data, and the XML document is converted into RDF data in consideration of the XML document schema, the elements of the XML document schema are considered. Since the attributes and the elements and attributes of the RDF document schema do not correspond one-to-one, all the information of the XML document schema cannot be converted into the RDF document schema. There is a problem that information in the schema of the system is missing.

  Therefore, the present invention has been made in view of the above-described problems, and in conversion between formats having different schema structures, such as converting structure description data into semantic description data, It is an object of the present invention to provide an apparatus and a method capable of converting into data after conversion without losing information held in the schema of the data before conversion.

  More specifically, when XML data is converted into RDF data, the object is to convert the XML data into RDF data without losing information of the XML schema.

  In order to solve the above-described conventional problems, the present invention provides a schema part conversion device used in a data conversion method for converting structure description data into semantic description data, wherein the schema of the structure description data includes the semantic description Provided is a schema part conversion device characterized by being converted into a data schema and a document.

  In one embodiment of the present invention, there is provided schema compatibility determining means for determining whether or not the schema element of the structure description data has compatibility with the schema of the semantic description data.

  In one embodiment of the present invention, an element dividing unit that divides an element into an element determined to be compatible and an element determined to be incompatible by the schema compatibility determining unit, and the compatibility A first description method conversion means for converting an element determined to be compatible into a schema of the semantic description data, and an element determined to be incompatible is converted into a document of the semantic description data And a second description method conversion means.

  In one embodiment of the present invention, it is characterized by comprising property complementing means for complementing the semantic description to the element determined to be incompatible and establishing it as a document of the semantic description data.

  In one embodiment of the present invention, including the schema of the semantic description data converted by the first description method conversion means and the semantic description data document converted by the second description method conversion means, It is treated as a schema part in the semantic description data.

  In one embodiment of the present invention, the structure description data is XML data, and the semantic description data is RDF data.

  The present invention is also a schema part conversion method used in a data conversion method for converting structure description data to semantic description data, wherein the schema element of the structure description data is compatible with the schema of the semantic description data. A schema compatibility determination step for determining whether or not the device has compatibility, and an element determined to be compatible by the schema compatibility determination step and an element determined to be incompatible An element division step, a first description method conversion step for converting the element determined to be compatible into a schema of semantic description data, and an element determined to be incompatible There is provided a schema part conversion method comprising: a second description method conversion step for converting a description data into a document.

  The present invention also includes a data conversion apparatus including the schema part conversion apparatus, a system including the data conversion apparatus, a program for executing the schema part conversion method, and a recording medium on which the program is recorded.

  With this configuration, the schema information of the structure description data can be converted into the schema of the semantic description data without being lost.

  Since the present invention is configured as described above, in the conversion between formats having different schema structures, such as converting structure description (Syntax) data into semantic description (Semantics) data, the schema of the data before conversion has It is possible to convert to converted data without losing information.

  The present invention will be described with reference to the following embodiments and drawings, which are for illustrative purposes only and are not intended to limit the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a block diagram of a data conversion apparatus according to the present invention. In the present embodiment, the broadcast station data conversion device converts TV Anytime data described in XML and TV Anytime XML Schema into data and schema described in RDF. Take an example for explanation. In the present embodiment, the data is metadata.

  First, the data conversion apparatus 100 includes a schema part conversion apparatus 101 and an instance part conversion apparatus 102. In order to convert the XML Schema 103 into the schema portion 108 described in RDF, the schema portion conversion apparatus 101 is used to convert the XML Schema. Further, the schema part conversion apparatus 101 includes means for determining and separating an XML Schema element that cannot be described as an RDF Schema or OWL 105 and an XML Schema element that can be described as an RDF Schema or OWL 105, and cannot be described as an RDF Schema or OWL 105. The XML Schema element performs data conversion by re-description as an RDF document 106.

  Further, in order to convert the XML document 104 into the RDF document 107, the XML document 104 is converted into the RDF document 107 using the instance unit conversion device 102.

  FIG. 2 shows a block diagram of the configuration of the schema part conversion apparatus 101 in the present embodiment.

  The schema part conversion apparatus 200 includes a schema compatibility determination unit 201, an element division unit 202, a first description method conversion unit 203, a second description method conversion unit 204, a property complementing unit 205, a class property. And an information providing unit 206.

  The schema compatibility determination unit 201 determines whether an element described in the XML Schema 103 can be described as an RDF Schema or OWL 105 or not. The element dividing unit 202 separates elements that can be described as RDF Schema or OWL 105 and elements that cannot be described. The first description method conversion unit 203 re-describes an XML Schema element that can be described in the RDF Schema or OWL 105 as the RDF Schema or OWL 105. The second description method conversion means 204 re-describes the XML Schema element that cannot be described as the RDF Schema or OWL 105 as the RDF document 106. The property complementing means 205 complements the meaning as a schema to the elements described in the XML Schema in the second description converting means 204. The class / property information adding unit 206 adds the property definition supplemented by the property complementing unit 205 to the RDF Schema or OWL 105. Further, the schema compatibility determination unit 201 can automatically determine the description impossible element using the conversion table 208 describing the conversion relationship between the XML Schema and the RDF Schema. In addition, when the XML Schema 103 is rewritten as the RDF Schema 105 in the first description method conversion means 203, new semantic information intended by the user or metadata creator is added between the elements of the XML Schema. And an additional semantic information adding means 207. This finds a new meaning between the elements.

  FIG. 5 shows an example of XML Schema 103 used in the present embodiment, FIG. 6 shows an example of RDF Schema or OWL 105, and FIG. 7 shows an RDF document 106 that holds schema information of XML Schema.

  FIG. 3 shows a block diagram of the configuration of the instance unit conversion device 300. The instance part conversion apparatus 300 includes semantic complementation determination means 301, third description method changing means 302, and property complementation means 303.

  The semantic complement determination unit 301 determines whether there is semantic content between the elements of the XML document 104. The property complementing unit 303 complements the property in response to the determination result of the semantic completion determining unit 301. The third description method conversion unit 302 receives the property complementation by the property complementing unit 303 and re-describes the XML document 104 as the RDF document 107.

  An example of the XML document 104 used in the present embodiment is shown in FIG. 8, and an example of the RDF document 107 is shown in FIG.

  The schema part conversion device 101 is used to convert the XML Schema 103 into the RDF Schema or OWL 105 and the RDF document 106, and the instance part conversion device 102 is used to convert the XML document 104 into the RDF document 107. The conversion flow is shown in FIG.

  First, the flow of conversion from the XML document 104 to the RDF document 107 is shown.

  In the input XML document 104, the semantic completion determination unit 301 determines whether or not there is a need for semantic completion between elements (S01). In this process, when the relationship between the subject and the predicate cannot be found between the elements described in the XML document 104, it is necessary to complement the property (predicate). When the necessity of complementation arises, the property complementation means 303 performs property complementation (S02). Specifically, since the relationship between the subject and the predicate cannot be found between the element called TVAMain and the element called ProgramDescription, the property hasElement that “TVAMain has an element called ProgramDescription” is complemented. On the other hand, if there is no need for complementation, the third description method conversion means 302 adds necessary descriptions to the RDF document such as RDF: ID, and re-describes the XML document as an RDF document (S03).

  The conversion from the XML document 104 to the RDF document 107 will be described by taking the XML document 104 in FIG. 8 and the RDF document 107 in FIG. 9 as examples. First, in L801, an element TVAMain is declared in the XML document. The semantic complementation determination means 301 extracts a semantic relationship between L801 and L802. An L802 ProgramDescription that is a child element of the L801 TVAMain has no instance or resource. In other words, it is impossible to describe the subject, predicate, and object unique to RDF that “ProgramDescription of TVAMAin is an instance”. Therefore, the property hasElement (L902) is sent between the elements of L801 and L802 by the property complementing unit 303 to the third description method changing unit 302 and complemented. As a result, the meaning that “hasElement of TVAMain is ProgramDescription” is established between the elements of L801 and L802. The properties are similarly complemented by the property complementing means 303 between the elements of L802 and L803 and between the elements of L803 and L804 (L903, L904). In L804, programId exists as an attribute of ProgramInformation, and has an instance “crid: // sample / main”. At this time, the meaning of the subject, predicate, and object is established in L804, “ProgramId of ProgramInformation is“ crid // sample / main ””. Therefore, ProgramId can be used as a property of ProgramInformation. However, since the ProgramInformation of L804 also holds the child element BasicDescription in L805, the property that L804 has the element L805 (L906) is complemented by the property complementing means 303. Therefore, in L905, the attribute ProgramId is described in the element as a property, and the property of having a child element is complemented by using hasElement in L906. These converted elements are output as the RDF document 107 shown in FIG.

  Next, the flow of conversion from the XML Schema 103 to the RDF schema 108 is shown. The XML Schema 103 input to the data conversion apparatus 100 is judged by the schema compatibility judgment unit 201 as to whether it can be described as RDF Schema or OWL 105 or not. The determination result by the schema compatibility determination unit 201 is transmitted to the element division unit 202. The element division unit 202 re-describes the XML Schema 103 as the RDF Schema or OWL 105 based on the determination result, and the XML Schema 103 as the RDF document 106. As elements to be described again (S04). It is determined that the description is to be rewritten as RDF Schema or OWL 105, and the separated element is rewritten from the XML Schema 103 to the RDF Schema or OWL 105 by the first description method conversion means 203 (S05). The XML Schema rewritten as RDF Schema or OWL 105 by the first description method conversion means 203 is output as RDF Schema or OWL 105. The schema compatibility determination unit 201 determines that the description cannot be described as the RDF Schema or OWL 105, and the separated XML Schema element is sent to the second description format conversion unit 204 for re-description as an RDF document. (S06). Then, the property complementing means 205 complements the properties necessary for establishing the meaning of the XML Schema element as an RDF document and re-description. Specifically, a property hasSchema that an element has schema information is prepared, and the element has a meaning as a schema (S07). Here, the property definition complemented to the RDF document from the property complementing means 205 is added to the RDF Schema or OWL 105 using the class / property information adding means 206 (S08). Similarly, the definition of the property supplemented to the RDF document by the property complementing unit 303 when the instance unit converting device 102 converts the XML document into the RDF document is also processed by the class / property information adding unit 205. It is added to Schema or OWL 105 (S08). The properties are complemented by the property complementing means 205, and the XML Schema is rewritten into an RDF document by the second description method converting means 204, and is output as an RDF document 106 having XML Schema information.

  The XML Schema 103 in FIG. 5, the RDF Schema or OWL 105 in FIG. 6 and the RDF document 106 in FIG. 7 are taken as an example, and the conversion from the XML Schema 103 to the RDF Schema or OWL 105 and the RDF document 106 will be described. First, in L501 of FIG. 5, an XML schema declaration is made. In L502, it can be seen that the type of TVAMainType is ComplexType. If TVAMAinType is a subclass of ComplexType, it can be expressed using RDF Schema or OWL 105, so the schema compatibility determination unit 201 transmits a determination result indicating that description is possible to the element division unit 202. The element dividing unit 202 separates the XML Schema element (L501) determined to be descriptible as the RDF Schema or OWL 105, and transmits it to the first description method conversion unit 203. The first description method changing unit 203 re-describes the separated XML Schema element (L501) as RDF Schema or OWL 105. In the example of the present embodiment, the XML Schema in FIG. 9 is converted into an RDF Schema (FIG. 6). Therefore, the XML Schema element (L502) is rewritten as RDF Schema (L601) by the first description method conversion means 203.

  In L503 of FIG. 5, there is an appearance order specification (element) as an element of TVAMainType, and elements are listed. The appearance order designation element is determined not to be described as RDF Schema by the schema compatibility determination unit 201, and the determination result is transmitted to the element division unit 202. The XML Schema element (L503) that cannot be described as the RDF Schema is separated and transmitted to the second description method conversion means 204. The second description method conversion means 204 re-describes the XML Schema element (L503) as an RDF document using the appearance order specification (RDF: Seq) in the RDF document. Here, in order to re-describe the XML Schema element (L503) as an RDF document (L701), the property complementing means 205 complements the property. Specifically, the meaning of having an element was added using a property called hasElement (L700).

  In L504, attribute items (attributes) of TVAMAinType are listed. This attribute term is also determined by the schema compatibility determination unit 201 as being impossible to describe in the RDF Schema, and the determination result is transmitted to the element separation unit 202. The separated XML Schema element (L504) is rewritten into an RDF document (L703) by using the second description method conversion means 204. At this time, the property hasSchema (L702) having schema information is complemented by the property complementing means 205, and is realized as an RDF document. The property complemented by the property complementing unit 205 is added to the RDF Schema 105 by the class / property information adding unit 206. The second description method conversion means 204 uses the appearance count designation (minOcurs) as a predicate (property) in the element (L503) of the XML Schema (FIG. 5) described in the RDF document (FIG. 6). Yes. This property information is added as RDF Schema (L602) to the RDF Schema (FIG. 6) using the class / property information adding means 206. By the means shown above, the XML Schema shown in FIG. 5 can be separated into the RDF Schema shown in FIG. 6 and the RDF document shown in FIG. 7 for conversion.

  According to the procedure described above, the XML Schema 103 can be converted into the RDF Schema or OWL 105 and the RDF document 106, and the XML document 104 can be converted into the RDF document 107 without causing loss of information.

  Although XML Schema is used as the schema indicating the structure of the XML document used in the present embodiment, DTD (Document Type Definition), which is the schema of the XML document, can be used by using a similar data conversion device. It is.

  Note that the XML document and XML Schema used in this embodiment are part of the TV Anytime document, but it is also possible to convert all the contents using a similar data conversion device.

  In this embodiment, the conversion table 208 holds information about whether or not the XML Schema 103 can be described as the RDF Schema or OWL 105 by using the XML Schema as the RDF Schema or OWL 105 only by the schema compatibility determination unit 201. In response to a request from the schema compatibility determination unit 201, the conversion table 208 can return correspondence information and automatically determine whether or not description is possible.

  In this embodiment, the case where the conversion to the RDF Schema is performed without losing the information held by the XML Schema has been described. However, the first description method conversion means is obtained by using the additional semantic information adding means 207. In 203, when XML Schema 103 is rewritten as RDF Schema or OWL 105, information intended by the user or information intended by the metadata creator can be newly added to the RDF Schema between the elements of XML Schema. Become. Specifically, by adding a description that “Synopsis, which is an element of TVAMain, is a comment expressing a scene of a program” using the additional semantic information adding means 207, new semantic information is added to the RDF Schema. Alternatively, it is possible to add to the OWL 105. By adding information intended by the user or metadata creator as semantic information between elements described in XML Schema, the utility value of semantic search in the RDF document at the time of metadata production is improved. It is effective because it can show another effect.

  In this embodiment, the TV Anytime document and the XML Schema are used as the XML document 104 and the XML Schema 103 input to the data conversion apparatus. However, any XML document such as, for example, Even MPEG-7 and XML Schema of the XML document can be converted.

  In this embodiment, the RDF document 106 that holds the XML Schema information and the RDF document 107 converted from the XML document are handled as different files, but can be handled as one file. A specific example is shown in FIG. In FIG. 10 showing the RDF document in a triple format, an instance part and a schema part are mixed in one RDF document.

  By handling two RDF documents as one file, it is effective because another effect that file management becomes easy can be exhibited. Neither is limited to this embodiment.

  The data conversion method for converting structure description data into semantic description data according to the present invention is useful for conversion between formats having different schema structures.

The block diagram of the data converter in embodiment Block diagram of schema part conversion apparatus according to the present invention Block diagram of an instance conversion device according to the present invention The flowchart which shows operation | movement of the data converter which concerns on embodiment The figure which shows an example of the input XML Schema in embodiment of this invention The figure which shows an example of RDF Schema output in embodiment of this invention The figure which shows an example of the RDF document output in embodiment of this invention The figure which shows an example of the XML document input in embodiment of this invention The figure which shows an example of the RDF document output in embodiment of this invention The figure which shows an example of the RDF document output in embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Data converter 101 Schema part converter 102 Instance part converter 103 XML Schema
104 XML document 105 RDF Schema or OWL
106 RDF document (schema information)
107 RDF document (instance information)
DESCRIPTION OF SYMBOLS 108 Schema part 109 Instance part 200 Schema part conversion apparatus 201 Schema compatibility determination means 202 Element division means 203 First description method conversion means 204 Second description method conversion means 205 Property complementing means 206 Class / property information addition means 207 Addition Meaning information adding means 208 Conversion table 300 Instance part conversion device 301 Meaning completion determining means 302 Third description method converting means 303 Property complementing means

Claims (7)

A schema part conversion device used in a data conversion method for converting structure description data into semantic description data,
The schema part conversion apparatus, wherein the schema of the structure description data is converted separately into a schema of the semantic description data and a document. The schema part conversion according to claim 1, further comprising schema compatibility determination means for determining whether or not an element of the schema of the structure description data has compatibility with the schema of the semantic description data. apparatus. An element dividing unit that divides the element into an element determined to be compatible and an element determined to be incompatible by the schema compatibility determining unit;
First description method conversion means for converting the element determined to be compatible into a schema of the semantic description data;
A second description method conversion means for converting the element determined to be incompatible into a document of the semantic description data;
The schema part conversion device according to claim 2, further comprising: 4. The schema part conversion device according to claim 3, further comprising property complementing means for complementing the semantic description to the element determined to be incompatible and establishing the semantic description data as a document. . The semantic description data schema converted by the first description method conversion means and the semantic description data document converted by the second description method conversion means are treated as a schema part in the semantic description data. The schema part conversion apparatus according to any one of claims 1 to 4, wherein the schema part conversion apparatus is provided. The structure description data is XML data;
The schema part conversion apparatus according to claim 1, wherein the semantic description data is RDF data. A schema part conversion method used in a data conversion method for converting structure description data into semantic description data,
A schema compatibility determination step for determining whether or not the schema element of the structure description data is compatible with the schema of the semantic description data;
An element dividing step of dividing the element into an element determined to be compatible and an element determined to be incompatible by the schema compatibility determining step;
A first description method conversion step for converting the element determined to be compatible into a schema of semantic description data;
A second description method conversion step for converting the element determined to be incompatible into a document of semantic description data;
A schema part conversion method comprising:

Images