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Ontology Based Extraction of RDF Data from the World Wide Web. Tim Chartrand A Thesis Proposal Research Supported By NSF. Introduction. World Wide Web Has a huge amount of existing information Designed primarily for human consumption Semantic Web Is an extension of WWW
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Ontology Based Extraction of RDF Data from the World Wide Web Tim Chartrand A Thesis Proposal Research Supported By NSF
Introduction • World Wide Web • Has a huge amount of existing information • Designed primarily for human consumption • Semantic Web • Is an extension of WWW • Gives information a well-defined meaning • Allows automation of tasks • DEG contribution – Extract data from the WWW • Proposed solution • Extract Semantic Web data from the WWW • Superimpose extracted data
User HTML Page HTML Page DAML Ontology Extraction Ontology Extraction Ontology Extraction Engine Extraction Engine RDF Browser RDF Data Relational Data Relational Data Overview of Proposed Research
User HTML Extraction Engine DAML Ontology Extraction Ontology Relational Data RDF Data mailto:tim@cs.byu.edu genealogy:fatherOf genealogy:age genealogy:fatherOf mailto:tyler@thechartrands.com 25 RDF – What is it? • Resource Description Framework • Language of the Semantic Web • Set of <subject><predicate><object> triples <mailto:tim@cs.byu.edu><genealogy#age>“25” <mailto:tim@cs.byu.edu><genealogy#fatherOf><mailto:tyler@thechartrands.com>
User HTML Extraction Engine DAML Ontology Extraction Ontology Relational Data RDF Data RDFS & DAML Core Concepts • Classes • daml:class – defines a class • rdfs:subClassOf – specifies the generalization of a class • Properties • daml:property – defines a binary relation, has a value • rdfs:domain – specifies class to which a property applies • rdfs:range – specifies possible values of a property
User HTML Extraction Engine DAML Ontology Extraction Ontology Relational Data RDF Data Example Ontology <daml:Class rdf:ID="Program"> <rdfs:label>Program</rdfs:label> </daml:Class> <daml:Class rdf:ID="Size"> <rdfs:label>Size</rdfs:label> </daml:Class> . . . <daml:Property rdf:ID="Name"> <rdfs:domain rdf:resource="#Program"/> <rdfs:range rdf:resource="&rdfs;Literal"/> <rdf:type rdf:resource="&daml;UniqueProperty"/> <rdf:type rdf:resource="&daml;UnambiguousProperty"/> </daml:Property> <daml:ObjectProperty rdf:ID="ProgSize"> <rdfs:domain rdf:resource="#Program"/> <rdfs:range rdf:resource="#Size"/> </daml:ObjectProperty> . . .
User HTML Extraction Engine DAML Ontology Extraction Ontology Relational Data RDF Data DAML OSM • Classes Non-lexical object sets • Properties Binary relationship sets between object sets • Literal properties Binary relationship sets between non-lexical and lexical object sets • Cardinality restrictions Participation constraints
User HTML Extraction Engine DAML Ontology Extraction Ontology Relational Data RDF Data DAML OSM <daml:Class rdf:ID="Program"> <rdfs:label>Program</rdfs:label> </daml:Class> <daml:Class rdf:ID="Size"> <rdfs:label>Size</rdfs:label> </daml:Class> . . . <daml:Property rdf:ID="Name"> <rdfs:domain rdf:resource="#Program"/> <rdfs:range rdf:resource="&rdfs;Literal"/> <rdf:type rdf:resource="&daml;UniqueProperty"/> <rdf:type rdf:resource="&daml;UnambiguousProperty"/> </daml:Property> <daml:ObjectProperty rdf:ID="ProgSize"> <rdfs:domain rdf:resource="#Program"/> <rdfs:range rdf:resource="#Size"/> </daml:ObjectProperty> . . .
User HTML Extraction Engine DAML Ontology Extraction Ontology Relational Data RDF Data Data Frames • Lexical object sets need data frame. • Use data-frame library • Match lexical object sets with data frames • Compare names • Stemming • Levenshtein edit distance • Soundex • Longest Common Subsequence • Choose most similar data frame
User HTML Extraction Engine DAML Ontology Extraction Ontology Relational Data RDF Data User Modification • Cardinality Constraints • Provide graphical ontology editor • Allow the user to edit participation constraints • Disallow the user to modify ontology structure • Data Frames • Allow user to edit mapping • Provide data frame editor • Allow user to edit or add data frames
User HTML Extraction Engine DAML Ontology Extraction Ontology Relational Data RDF Data Extracting the Data
User HTML Extraction Engine DAML Ontology Extraction Ontology Relational Data RDF Data http://www.downloads.com/Program1001 rdf:type software:name software:ProgSize software:Program software:version software:OperatingSystem Stick Death 1.0 Windows 3.x/95/98/Me/NT/2000/X rdf:type software:SizeVal software:SizeUnit software:Size 2.66 MB Convert to RDF
User HTML Extraction Engine DAML Ontology Extraction Ontology Relational Data RDF Data Superimposed Data
Contributions • Advancement of Semantic Web • Application of Information Extraction to building Semantic Web • Semantic Web data as superimposed information • Algorithm for ontology conversion