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My Seminar Presentation in Isfahan University of Technology
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پاسخگویی به سوال در داده های پیوندی
دکتر محمدحسین سراییاستاد راهنما: رضا رمضانی
Question Answering in Linked Data
1390پاییز
ج(ات نک1م و( الذین( او1توالع-لم د(ر( ا م- نو1 ی(رفع1 الله( الذین( آم(
دانشکده برق و کامپیوتر – دانشگاه صنعتی اصفهان
QALD
Question Answering over
Linked Data
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The Web of Documents
Traditional Web, Hypertext WebAnalogy
A global file systemDesigned for
Human consumptionPrimary objects
DocumentsLinks
Untyped Between documents (or parts of documents)
Degree of structure in object Fairy low
Semantics of content and links implicit
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The Web of Documents
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The Web of Data
AnalogyA global data space
Designed forMachines first, humans later
Primary objectsThings (description of things)
LinksTypedBetween things
Degree of structure in objectsHigh
Semantic of content and linksExplicit
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The Web of Linked Data
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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
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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
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A Taste of Linked Data
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A Taste of Linked Data (Cont.)
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Linked Data Technology Stack
URI
HTTPRDFS / OWL
RDF / RDF Links
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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
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LOD Cloud : May 2007
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LOD Cloud : July 2007
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LOD Cloud : August 2007
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LOD Cloud : November 2007
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LOD Cloud : February 2008
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LOD Cloud : March 2009
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LOD Cloud : July 2009
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LOD Cloud : September 2010
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LOD Cloud : September 2011
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Retrieval Process
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• a) Query construction• b) Search algorithm of the system• c) Presentation of the results
Search EnginesQuery A lot of related Web Pages
QA SystemsQuestion Exact Answer
Retrieval Process (Cont.)
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Query Analyzer
Query
A lot ofWeb Pages
WWW
Crawler
RequestWeb Pages
IndexFile
Indexer
Web Pages
Index TermsSearch
Ranking
Results DocDatastore
Web Pages
UI
Query
Ranked Results
Web Pages
• Traditional SE
Some Problems
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• Information search with search engines
Therefore, what is needed?
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• 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
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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
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Question Answering (Cont.)
• Open Domain QA System
Question Analysis
Answer Selection
Question Query
AnswerType
Documents
Answer (s)
Question
Answer (s)
UI
Document Analysis
Passages
Document RetrievalSystems
Document Retrieval
Open DomainOntology
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Question Answering (Cont.)
• Restricted Domain QA System
Question Analysis
AnswerPost Processing
Question Query
Answer (s)
Question
Answer (s)
UI
AnswerRetrieval
Answer (s)
Data
Open DomainOntology
Lexicon
DomainOntology
Knowledge Base
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
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FREyA Algorithm
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Questions?
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وب معنایی، وب فرداسراسCر تکامCل بشCر بCه دلیCل خیCال پCردازی وی بCوده اسCت. آنچCه دیCروز یCک رویCا بCود؛ امCروز یCک واقعیت اسCت و آنچCه امCروز یCک خواهCCد واقعیت بCCه فCCردا رویاسCCت؛
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