Heiko Haller, Felix Kugel | FZI, OIO Semantic Web€¦ · Semantic Web - Definition „The Semantic Web is an extension of the current web in which information is given well-defined

Heiko Haller, Felix Kugel | FZI, OIO

Semantic Web...zum Anfassen

Heiko Haller, Felix Kugel | FZI, OIO

Semantic Web...was steckt dahinter?

Heiko Haller, Felix Kugel


Übersicht

• Hintergrund: Metadaten und Ontologien• Beispiel: Reuters Calais Web Service• Semantic Web mit Java

• Semantic Wave 2008 Report (Project10X)


Semantic Web - Definition

„The Semantic Web is an extension of the current web in which information is given well-defined meaning, better enabling computers and people to work in cooperation.“

Scientific American, 2001


Semantic Web - Definition

„A set of formats and languages that find and analyze data on the World Wide Web, allowing consumers and businesses to understand all kinds of useful online information.“

Scientific American, 2007


Beispiel: Kontaktadresse


Adresse in HTML

FZI Forschungszentrum Informatik Haid-und-Neu-Straße 10-14 76131 Karlsruhe Tel.: +49 721 9654-0 Fax: +49 721 9654-909Orientation in Objects GmbH Weinheimer Str. 68 68309 Mannheim 


Adresse mit hCard - Microformat<div class="adr">

FZI Forschungszentrum Informatik <div class="street-address">

Haid-und-Neu-Straße 10-14</div>

76131Karlsruhe

+49 721 9654-0



</div>


Metadaten

• Metadaten sagen etwas aus über die Bedeutung bestimmter Daten

• Microformats– Konventionen für HTML

• RDF– Basis des Semantic Web


GRDDL: Microformats → RDF

Quelle: W3C


RDF – Resource Description Framework

• Datenformat für Metadaten– z.B. im RDF-XML Serialisierungsformat

• RDFS (RDF Schema)– Metamodell für RDF- Metadaten– Analog zu XML und XML Schema


RDF: Tripel und Graphen

• Statements / Tripel• Resourcen• Literale

Basic semantic technologies

Angola Africalocated in

Zambia

located in

borders

Country Continent

http://wiki.ontoworld.org/index.php/_Angolahttp://wiki.ontoworld.org/index.php/_Africa

http://wiki.ontoworld.org/index.php/_Relation-3ALocated_in

http://wiki.ontoworld.org/index.php/_Zambia

http://w

iki.ontoworld

.org/index.php/_Relatio

n-3ALocated_in

http://wiki.ontow

orld.org/index.php/_Relation-3AB

orders

http://wiki.ontoworld.org/index.php/_Category-3ACountry

http://wiki.ontoworld.org/index.php/_Category-3AContinent

http://wiki.ontoworld.org/index.php/_Angolahttp://wiki.ontoworld.org/index.php/_Africa

http://wiki.ontoworld.org/index.php/_Relation-3ALocated_in

http://wiki.ontoworld.org/index.php/_Zambia

http://w

iki.ontoworld

.org/index.php/_Relatio

n-3ALocated_in

http://wiki.ontow

orld.org/index.php/_Relation-3AB

orders

http://wiki.ontoworld.org/index.php/_Category-3ACountry

http://wiki.ontoworld.org/index.php/_Category-3AContinent

Angola

http://www.w3.org/2000/01/rdf-schema#label

Africalocated in

Zambia

Country

borders

Continent

Angola Africalocated in

Zambia

located in

borders

Country Continent


RDF und XHTML

<?xml version="1.0" encoding="utf-8"?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <title>Semantic Web zum Anfassen</title> <meta http-equiv="Content-type" content='text/html; charset="utf-8"' /> <link rel="alternate" type="application/rdf+xml" title="RDF Version" href="example.rdf" /> </head> <body> ...

• XHTML:


RDF und XHTML

<?xml version="1.0"?><rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.1/"> <rdf:Description rdf:about="http://example.org/document.html"> <dc:title>Example document</dc:title> <dc:description>An example document about nothing.</dc:description> <dc:creator>The author</dc:creator> </rdf:Description></rdf:RDF>

• RDF:


Wo kommen die Metadaten her?

• Manuell:– Microformats in Webseiten– RDF-Dateien, die passend zu HTTP

Ressourcen im Web publiziert werden– Web 2.0 style (social tagging etc.)


Wo kommen die Metadaten her?

• Automatisch:– Annotations- Dienste (z.B. Calais)– D2R (FU Berlin)– semanticdesktop.org


Beispiel: Calais Web Service

• Service der Nachrichtenagentur Reuters• Für jedermann (40.000 Aufrufe pro Tag)• Extrahiert RDF- Metadaten aus Texten


SPARQL - RDF queries

• Abfragesprache für RDF- Graphen• Ähnlich SQL


Beispiel: SPARQL mit Jena

• Jena Semantic Web Toolkit• Ursprünglich HP, jetzt Sourceforge• API für RDF, RDFS, OWL, SPARQL• Inferenzmaschine• Persistenz


Reasoning

• „Schlussfolgern“• „Sehr mächtige“ Queries:

– „Um die Ecke“ fragen– Finden von Subgraphen– Konstruktion neuer Graphen

• Reasoner / Inferenzmaschine



Ontologien

• „Gemeinsam genutzte Konzeptualisierung von Wissen über eine Fachdomäne“

• Bausteine:– Klassen– Eigenschaften (Properties)– Instanzen


Ontologien: Sprachstandards

• Alte:– XML Schema– DAML

• Neue:– RDFS– OWL


OWL (Ontology Web Language)

• Die Mächtigkeit einer Wissensrepräsentationssprache hat Konsequenzen für die algorithmische Komplexität des Reasoning

• Deshalb:– OWL DL (Description Logic)– OWL Full


Ontologien: Werkzeuge


Ontologien: Methoden

• Ontology Design• Ontology Alignment• Ontology Merging• Ontology Lifecycle Management• Ontology Evolution


Ontologien: Marktübersicht

• Dublin Core• WordNet• Cyc• ...

MarryingWikipedia and the Semantic Web

Semantics to Wikipedia

Wikipedia today

Brač is a Croatian island in the Adriatic Sea. The island has a population of 13,000, living in numerous little towns, ranging from the 'main town' Supetar, with more than 2,500 inhabitants, to Novo Selo, where only a dozen people live.Today, Brač lives mostly on tourism, but fishing and agriculture (especially wine and olives) are very important too, as is selling its precious, white stone (which was used in building Diocletian's Palace in Split, and is built into the White House in Washington, DC, too).Category: Croatian Island

http://en.wikipedia.org/wiki/Croatia

http://en.wikipedia.org/wiki/Adriatic_Sea

http://en.wikipedia.org/w/index.php?title=Supetar&action=edit

http://en.wikipedia.org/wiki/Novo_Selo

http://en.wikipedia.org/wiki/Novo_Selo

http://en.wikipedia.org/wiki/Tourism

http://en.wikipedia.org/wiki/Fishing

http://en.wikipedia.org/wiki/Agriculture

http://en.wikipedia.org/wiki/Wine

http://en.wikipedia.org/wiki/Olive

http://en.wikipedia.org/wiki/Diocletian%27s_Palace

http://en.wikipedia.org/wiki/Split

http://en.wikipedia.org/wiki/White_House



How are they linked?

Brač CroatiaBrač Adriatic SeaBrač SupetarBrač Novo SeloBrač tourismBrač fishingBrač agriculture

How are they linked?

Brač belongs to CroatiaBrač located in Adriatic SeaBrač has town SupetarBrač has town Novo SeloBrač lives on tourismBrač lives on fishingBrač lives on agriculture

Brač is a [[Croatia]]n island with an area of 396 km².

Brac is a[[belongs to::Croatia]]n island with an area of [[area:=396 km²]].

Typed links

Extend wiki with typed links So the computer “understands” it

Brač Croatiabelongsto

area396 km²

Inline queries

<ask>[[Category:Country]][[located in::Africa]][[population:=>1,000,000]][[population:=<10,000,000]][[population:=*]][[area:=*km²]][[borders::*]]

</ask>



semanticdesktop.org

• Semantisches Personal Information Management

• Ontologie- Framework für Desktop Artefakte

16 Partners• Unites industry, research, and users

Nepomuk means… Networked

P2P-technology for efficient on-the-fly exchange

Environment for existing applications can be interlinked

Personal Ontology-based every user maintains own structures shared semantics emerge, like folksonomies

Management of Unified Knowledge knowledge is connected across desktop borders semantically enhanced browsing and searching

Service registry and middleware

Peer-to-Peer storage

Services(search,

text analysis,adaptors)

Local storage(RDF know-ledge base)

User Interfacecomponents

(mapping, wiki, search interface, ontology browser)

colleague

friend

acquaintance

e-mail

person

Topic

website document

image

event

person

Desktop: Help to manage personal knowledge/information(documents, files, e-mail, bookmarks, notes)

Semantic: Make content available to automated processing Social: Enable exchange across individual boundaries

Social Semantic Desktop

colleague

friend

acquaintance

e-mail

person

Topic

website document

image

event

person

Semantic search over the whole knowledge repository Which documents are authored by people working for X? Show me pictures of these authors

Connect Outlook-contacts with Word-files Person X has written document Z as a response to email Y

Social Semantic Desktop


Linkliste

• http://www.oio.de/jax-2008/semantic-web-zum-anfassen.htm

Documents

Heiko Haller, Felix Kugel | FZI, OIO Semantic Web€¦ · Semantic Web - Definition „The Semantic Web is an extension of the current web in which information is given well-defined