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Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
Question answering in linked data
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Question answering in linked data

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My Seminar Presentation in Isfahan University of Technology

My Seminar Presentation in Isfahan University of Technology

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  • 1. QALD Question Answering over Linked Data 2
  • 2. The Web of Documents  Traditional Web, Hypertext Web  Analogy  A global file system  Designed for  Human consumption  Primary objects  Documents  Links  Untyped  Between documents (or parts of documents)  Degree of structure in object  Fairy low  Semantics of content and links  implicit 3
  • 3. The Web of Documents 4
  • 4. The Web of Data  Analogy  A global data space  Designed for  Machines first, humans later  Primary objects  Things (description of things)  Links  Typed  Between things  Degree of structure in objects  High  Semantic of content and links  Explicit 5
  • 5. The Web of Linked Data 6
  • 6. Linked Data • Is about using the Web to create typed links between data from different sources • Refers to data published on the Web in such a way that – It is machine-readable – Its meaning is explicitly defined – It is linked to other datasets – It can be linked to from external datasets 7
  • 7. Properties of the Web of Data • It is generic – Can contain any type of data • Data about anything – Anyone can publish data – No constraints on choice of vocabularies – entities are connected by RDF links 8
  • 8. A Taste of Linked Data 9
  • 9. A Taste of Linked Data (Cont.) 10
  • 10. Linked Data Technology Stack URIHTTP RDFS / OWL RDF / RDF Links 11
  • 11. Ontology , RDF • Ontology provides a means to vocabularies and link’s semantics on linked data. • RDF provides a generic, graph-based data model to structure and link data that describes things • A triple [subject, predicate, object] – Subject: a URI – Predicate: a URI – Object: a URI or a string literal 12
  • 12. LOD Cloud : May 2007 13
  • 13. LOD Cloud : July 2007 14
  • 14. LOD Cloud : August 2007 15
  • 15. LOD Cloud : November 2007 16
  • 16. LOD Cloud : February 2008 17
  • 17. LOD Cloud : March 2009 18
  • 18. LOD Cloud : July 2009 19
  • 19. LOD Cloud : September 2010 20
  • 20. LOD Cloud : September 2011 21
  • 21. Retrieval Process 22 • a) Query construction • b) Search algorithm of the system • c) Presentation of the results Search Engines Query A lot of related Web Pages QA Systems Question Exact Answer
  • 22. Retrieval Process (Cont.) 23 Query Analyzer Query A lot of Web Pages WWW Crawler RequestWeb Pages Index File Indexer Web Pages Index TermsSearch Ranking Results Doc Datastore Web Pages UI Query Ranked Results Web Pages • Traditional SE
  • 23. Some Problems 24 • Information search with search engines
  • 24. Therefore, what is needed? 25 • Assign meta data to information objects • Content description with concepts and relations between them • Provision of background knowledge • Provision of the semantics of relations for query extension, ontology integration, etc. RDF RDF Schema, OWL, Rules
  • 25. 26 Question Answering • Question answering (QA) systems take users’ natural language questions and automatically locate answers from large collections of documents. • Two types of QA systems – Closed-Domain (or restricted domain) Question Answering – Open-Domain Question Answering
  • 26. 27 Question Answering (Cont.) • Open Domain QA System Question Analysis Answer Selection Question Query Answer Type Documents Answer (s) Question Answer (s) UI Document Analysis Passages Document Retrieval Systems Document Retrieval Open Domain Ontology
  • 27. 28 Question Answering (Cont.) • Restricted Domain QA System Question Analysis Answer Post Processing Question Query Answer (s) Question Answer (s) UI Answer Retrieval Answer (s) Data Open Domain Ontology Lexicon Domain Ontology Knowledge Base
  • 28. Related Works • AquaLog – Vanessa Lopez, Victoria Uren, Enrico Motta, Michele Pasin. • PowerAqua – Vanessa Lopez, Andriy Nikolov, Marta Sabou, Victoria Uren, Enrico Motta, Mathieu d’Aquin • QASYO – for YAGO Ontology • AutoSPARQL 29
  • 29. FREyA Algorithm 30
  • 30. Questions? 31 Email: R.Ramezani@ec.iut.ac.ir

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