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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
Heiko Haller, Felix Kugel
Übersicht
• Hintergrund: Metadaten und Ontologien• Beispiel: Reuters Calais Web Service• Semantic Web mit Java
• Semantic Wave 2008 Report (Project10X)
Heiko Haller, Felix Kugel
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
Heiko Haller, Felix Kugel
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
Heiko Haller, Felix Kugel
Beispiel: Kontaktadresse
Heiko Haller, Felix Kugel
Adresse in HTML
<P>FZI Forschungszentrum Informatik<BR>Haid-und-Neu-Straße 10-14<BR>76131 Karlsruhe<BR>Tel.: +49 721 9654-0<BR>Fax: +49 721 9654-909</P><p><b>Orientation in Objects GmbH</b><br />Weinheimer Str. 68<br />68309 Mannheim<br /></p>
Heiko Haller, Felix Kugel
Adresse mit hCard - Microformat<div class="adr">
FZI Forschungszentrum Informatik<BR><div class="street-address">
Haid-und-Neu-Straße 10-14</div><span class="postal-code">
76131</span><span class="locality">Karlsruhe</span><span class="tel">
<span class="value">+49 721 9654-0
</span></span>
</div>
Heiko Haller, Felix Kugel
Metadaten
• Metadaten sagen etwas aus über die Bedeutung bestimmter Daten
• Microformats– Konventionen für HTML
• RDF– Basis des Semantic Web
Heiko Haller, Felix Kugel
GRDDL: Microformats → RDF
Quelle: W3C
Heiko Haller, Felix Kugel
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
Heiko Haller, Felix Kugel
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
Heiko Haller, Felix Kugel
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:
Heiko Haller, Felix Kugel
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:
Heiko Haller, Felix Kugel
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.)
Heiko Haller, Felix Kugel
Wo kommen die Metadaten her?
• Automatisch:– Annotations- Dienste (z.B. Calais)– D2R (FU Berlin)– semanticdesktop.org
Heiko Haller, Felix Kugel
Beispiel: Calais Web Service
• Service der Nachrichtenagentur Reuters• Für jedermann (40.000 Aufrufe pro Tag)• Extrahiert RDF- Metadaten aus Texten
Heiko Haller, Felix Kugel
SPARQL - RDF queries
• Abfragesprache für RDF- Graphen• Ähnlich SQL
Heiko Haller, Felix Kugel
Beispiel: SPARQL mit Jena
• Jena Semantic Web Toolkit• Ursprünglich HP, jetzt Sourceforge• API für RDF, RDFS, OWL, SPARQL• Inferenzmaschine• Persistenz
Heiko Haller, Felix Kugel
Reasoning
• „Schlussfolgern“• „Sehr mächtige“ Queries:
– „Um die Ecke“ fragen– Finden von Subgraphen– Konstruktion neuer Graphen
• Reasoner / Inferenzmaschine
Heiko Haller, Felix Kugel
Heiko Haller, Felix Kugel
Ontologien
• „Gemeinsam genutzte Konzeptualisierung von Wissen über eine Fachdomäne“
• Bausteine:– Klassen– Eigenschaften (Properties)– Instanzen
Heiko Haller, Felix Kugel
Ontologien: Sprachstandards
• Alte:– XML Schema– DAML
• Neue:– RDFS– OWL
Heiko Haller, Felix Kugel
OWL (Ontology Web Language)
• Die Mächtigkeit einer Wissensrepräsentationssprache hat Konsequenzen für die algorithmische Komplexität des Reasoning
• Deshalb:– OWL DL (Description Logic)– OWL Full
Heiko Haller, Felix Kugel
Ontologien: Werkzeuge
Heiko Haller, Felix Kugel
Ontologien: Methoden
• Ontology Design• Ontology Alignment• Ontology Merging• Ontology Lifecycle Management• Ontology Evolution
Heiko Haller, Felix Kugel
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
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>
Heiko Haller, Felix Kugel
Heiko Haller, Felix Kugel
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
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
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
Heiko Haller, Felix Kugel
Linkliste
• http://www.oio.de/jax-2008/semantic-web-zum-anfassen.htm