OpenHPI 1.7 - Applications in the Web of Data

Dr. Harald Sack

Hasso Plattner Institute for IT Systems Engineering

University of Potsdam

Spring 2013

Semantic Web Technologies

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Lecture 1: The Web of Data 07: Applications in the Web of Data

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Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam

Lecture 1: The Web of Data

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Open HPI - Course: Semantic Web Technologies


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07: Applications in the Web of Data OpenHPI - Course Semantic Web Technologies - Lecture 1: The Web of Data


4 Linked Data□ Linked Open Data (LOD) denote publicly available (RDF) Data in the Web, identified via

URI and accessable via HTTP. Linked data link to other data via URI.

Semantic Web Technologies Applications on the Web of Data

The ,Web of Data‘

• >31 billion facts

• >500 million links (Oct. 2011)


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http://www.bbc.co.uk/music




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What is so special about the BBC Music Website?

• Information is dynamically aggregated from external, publicly available data (Wikipedia, MusicBrainz,...)

• no Screen Scraping

• no specialized API

• data available als Linked Open Data

• data access via simple HTTP Request

• data is always up-to-date without manual interaction

Search Engines - Document Retrieval

•Search Engine Query String: “Jaguar of 2000“


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• Refine ,jaguar‘ CAR or ANIMAL or OPERATINGSYSTEM etc. ?Refine: CAR




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•Name: Jaguar E Type•Category: Car•...• ConstructionYear <Integer>• technicalParameter• CylinderCapacity <Integer>• Power <Integer>• ...

• ...

Knowledge Representation(Ontology, Linked Data)




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•Refine ,2000‘ ConstructionYear or technicalParameter ?Refine: ConstructionYear

•Name: Jaguar E Type•Category: Car•...• ConstructionYear <Integer>• technicalParameter• CylinderCapacity <Integer>• Power <Integer>• ...

• ...

Knowledge Representation(Ontology, Linked Data)




9Search Engines - Document Retrieval

• General Problems:

• correct interpretation of query string

• correct identification of entities

• automatic disambiguation

• usability

• personalization


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Search Engines - Fact Retrieval

•Query String: “Where can I fill up the tank at a considerable discount?“

Answer : - Hohenfelden, xy-Str. 32 -> Super leaded, 1,99 € - fuel-efficient route will be passed to navigation - drive only at half throttle for saving fuel…


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dbpedia-owl:mission

dbpedia:Neil_Armstrong

dbpedia:Apollo_11dbpedia-owl:mission

category:Apollo_program

dcterms:subject

dbpedia:Apollo_13

dcterms:subject

yago:Space_accidents_and_incidents

rdf:type

rdf:type

dbpedia:Space_Shuttle_Challenger

dbpedia-owl:mission

dbpedia:Buzz_Aldrin

dbpedia:Michael_Collins

Search Engines - Exploratory Search


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Intelligent Agents in the Semantic Web

User

retrieval service(e.g. Google)

WWW documents

presentation service(e.g. Firefox)

WWW


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Intelligent Agents in the Semantic Web

User

retrieval service(e.g. Google)

WWW documents

presentation service(e.g. Firefox)

WWW

WWW documents

SemanticWeb

User

personalassistant

intelligentinfrastructure

services


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3 Generations of Web Documents

staticweb pages

HTML / CSS

1. Generation


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staticweb pages

HTML / CSS

1. Generation

interactiveweb pages

dynamicweb pages

JavaScript / Applets

Data Base AccessTemplate-based

Generation

2. Generation


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staticweb pages

HTML / CSS

1. Generation

interactiveweb pages

dynamicweb pages

JavaScript / Applets

Data Base AccessTemplate-based

Generation

2. Generation

adaptiveweb pages

virtualweb pages

User ModelsMachine Learning

Online Layout

NetbotsInformation ExtractionPresentation Planning

3. Generation


14 Toolbox for the Semantic Web

•Standardized languages to express semantics of information content in the Web (XML/XSD, RDF(S), OWL, RIF)

•Tools to use semantic information in the Web (RDFa, GRDDL, ...)

•Various fields of computer science:

• artificial intelligence

• linguistics

• cryptography

• data bases

• theoretical computer science

• computer architecture

• software engineering

• systems theory

• computer networks


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Lecture 2: Basic Architecture of the Semantic Web

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OpenHPI 1.7 - Applications in the Web of Data

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