Ontology Based Extraction of RDF Data from the World Wide Web

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Ontology Based Extraction of RDF Data from the
World Wide Web

• Tim Chartrand
• A Thesis Proposal
• Research Supported By NSF

2
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

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Overview of Proposed Research
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RDF What is it?

• Resource Description Framework
• Language of the Semantic Web
• Set of ltsubjectgtltpredicategtltobjectgt triples
• ltmailtotim_at_cs.byu.edugtltgenealogyagegt25
• ltmailtotim_at_cs.byu.edugtltgenealogyfatherOfgtltmailt
  otyler_at_thechartrands.comgt

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RDFS DAML

• Core Concepts
• Classes
• damlclass defines a class
• rdfssubClassOf specifies the generalization of
  a class
• Properties
• damlproperty defines a binary relation, has a
  value
• rdfsdomain specifies class to which a property
  applies
• rdfsrange specifies possible values of a
  property

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Example Ontology

• ltdamlClass rdfID"Program"gt
• ltrdfslabelgtProgramlt/rdfslabelgt
• lt/damlClassgt
• ltdamlClass rdfID"Size"gt
• ltrdfslabelgtSizelt/rdfslabelgt
• lt/damlClassgt
• . . .
• ltdamlProperty rdfID"Name"gt
• ltrdfsdomain rdfresource"Program"/gt
• ltrdfsrange rdfresource"rdfsLiteral"/gt
• ltrdftype rdfresource"damlUniqueProperty"/gt
• ltrdftype rdfresource"damlUnambiguousPropert
  y"/gt
• lt/damlPropertygt
• ltdamlObjectProperty rdfID"ProgSize"gt
• ltrdfsdomain rdfresource"Program"/gt
• ltrdfsrange rdfresource"Size"/gt
• lt/damlObjectPropertygt
• . . .

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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

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DAML ? OSM

• ltdamlClass rdfID"Program"gt
• ltrdfslabelgtProgramlt/rdfslabelgt
• lt/damlClassgt
• ltdamlClass rdfID"Size"gt
• ltrdfslabelgtSizelt/rdfslabelgt
• lt/damlClassgt
• . . .
• ltdamlProperty rdfID"Name"gt
• ltrdfsdomain rdfresource"Program"/gt
• ltrdfsrange rdfresource"rdfsLiteral"/gt
• ltrdftype rdfresource"damlUniqueProperty"/gt
• ltrdftype rdfresource"damlUnambiguousPropert
  y"/gt
• lt/damlPropertygt
• ltdamlObjectProperty rdfID"ProgSize"gt
• ltrdfsdomain rdfresource"Program"/gt
• ltrdfsrange rdfresource"Size"/gt
• lt/damlObjectPropertygt
• . . .

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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

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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

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Extracting the Data
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Convert to RDF
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Superimposed Data
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Contributions

• Advancement of Semantic Web
• Application of Information Extraction to building
  Semantic Web
• Semantic Web data as superimposed information
• Algorithm for ontology conversion