wtf is semantic web?
Post on 15-Jul-2015
737 Views
Preview:
TRANSCRIPT
Normal Web is about making information accessible to people.
Semantic Web is about making information more accessible
to software.
Thank you Wikipedians
(Thank you, Wikipedians)
oh well, it'll
http://en.wikipedia.org/wiki/Michael_Jackson_(footballer)
• Give important things identifiers
How?
407161495 ?
footballer_f285n ?
michael_jackson_27 ?
http://en.wikipedia.org/wiki/Michael_Jackson_(footballer)
URIs and URLs
• They look exactly like URLs
• In fact, URLs are a type of URI
URI: An identifier
URL: An identifier that points to a document
• They look exactly like URLs
• In fact, URLs are a type of URI
http://en.wikipedia.org/wiki/Michael_Jackson_(footballer)
URL
URI
URIs and URLs
• They look exactly like URLs
• In fact, URLs are a type of URI
http://milesworthington.com/Michael_Jackson(page does not exist)
URL
URI
URIs and URLs
URIs and URLs
• They look exactly like URLs
• In fact, URLs are a type of URI
Often the same.
But URIs do not always point to actual pages. Sometimes they are just names.
• Give important things identifiers
• Also give identifiers to the relationships between things
How?
http://jimsblog.com/michael_jackson_match.html
http://en.wikipedia.org/wiki/Michael_Jackson_(footballer)
Traditional Web links
http://jimsblog.com/michael_jackson_match.html
foaf:primaryTopic
http://en.wikipedia.org/wiki/Michael_Jackson_(footballer)
Semantic Web links
http://jimsblog.com/michael_jackson_match.html
foaf:primaryTopic
http://en.wikipedia.org/wiki/Michael_Jackson_(footballer)
(URI in disguise)
http://jimsblog.com/michael_jackson_match.html
http://xmlns.com/foaf/0.1/primaryTopic
http://en.wikipedia.org/wiki/Michael_Jackson_(footballer)
Jim’s blog post
has a the primary topic of
Michael Jackson the football player
Jim’s blog post
has a the primary topic of
Michael Jackson the football player
This is referred to as a “triple”
DBpedia.org
• The Semantic Web version of Wikipedia
• Contains all the same content from Wikipedia
• Everything is given a URI
• Relationships between things are also expressed with a URI
• Uses Tim’s Linked Data principles
MJ’s DBpedia URI
http://dbpedia.org/resource/Michael_Jackson
http://dbpedia.org/resource/Michael_Jackson http://dbpedia.org/page/Michael_Jackson
http://dbpedia.org/resource/Michael_Jackson http://dbpedia.org/data/Michael_Jackson.xml
Michael Jackson
was born in
Gary, Indiana
“Triples”
“Triples”
http://dbpedia.org/resource/Michael_Jackson
http://dbpedia.org/ontology/birthPlace
http://dbpedia.org/resource/Gary%2C_Indiana
“Triples”
SUBJECT
PREDICATE
OBJECT
“Triples”
http://dbpedia.org/resource/Michael_Jackson
http://dbpedia.org/ontology/birthDate
“1958-08-29”
http://www.imdb.com/name/nm0001391/
http://www.w3.org/2002/07/owl#sameAs
http://dbpedia.org/resource/Michael_Jackson
RDF
• “Resource Description Framework”
• Provides a way to add identifiers (URIs)to content
• Comes in many flavors
RDF
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .@prefix dc: <http://purl.org/dc/elements/1.1/> .@prefix ex: <http://example.org/stuff/1.0/> .
<http://www.w3.org/TR/rdf-syntax-grammar> dc:title "RDF/XML Syntax Specification (Revised)" ; ex:editor [ ex:fullname "Dave Beckett"; ex:homePage <http://purl.org/net/dajobe/> ] .
Turtle format
RDF
<http://www.w3.org/2001/sw/RDFCore/ntriples/> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> ↵ <http://xmlns.com/foaf/0.1/Document> .<http://www.w3.org/2001/sw/RDFCore/ntriples/> <http://purl.org/dc/terms/title> "N-Triples"@en-US .<http://www.w3.org/2001/sw/RDFCore/ntriples/> <http://xmlns.com/foaf/0.1/maker> _:art .<http://www.w3.org/2001/sw/RDFCore/ntriples/> <http://xmlns.com/foaf/0.1/maker> _:dave .
_:art <http://www.w3.org/1999/02/22-rdf-syntax-ns#> <http://xmlns.com/foaf/0.1/Person> ._:art <http://xmlns.com/foaf/0.1/name> "Art Barstow".
_:dave <http://www.w3.org/1999/02/22-rdf-syntax-ns#> <http://xmlns.com/foaf/0.1/Person> ._:dave <http://xmlns.com/foaf/0.1/name> "Dave Beckett".
N-triples format
RDF
<rdf:RDF xmlns="http://xmlns.com/foaf/0.1/" xmlns:dc="http://purl.org/dc/terms/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"> <Document rdf:about="http://www.w3.org/2001/sw/RDFCore/ntriples/"> <dc:title xml:lang="en-US">N-Triples</dc:title> <maker> <Person rdf:nodeID="art"> <name>Art Barstow</name> </Person> </maker> <maker> <Person rdf:nodeID="dave"> <name>Dave Beckett</name> </Person> </maker> </Document></rdf:RDF>
RDF/XML
The Compromise: RDFa
• RDF that lives inside an HTML document
• The “a” stands for attributes
• Uses attributes on HTML tags to hold identifiers
The Compromise: RDFa
<p xmlns:dc="http://purl.org/dc/elements/1.1/" about="http://www.example.com/books/wikinomics"> In his latest book <cite property="dc:title">Wikinomics</cite>, <span property="dc:creator">Don Tapscott</span> explains deep changes in technology, demographics and business. The book is due to be published in <span property="dc:date" content="2006-10-01">October 2006</span>.</p>
RDFa
Geek Reason
When most of the Web is published with RDF/RDFa it becomes a giant database
that we can efficiently query.
... a unified API for the Web
Geek Reason
“Find all <type:blog_post> that are <type:book_review> for <My_Favorite_Book> published between <date:one_month_ago> and <date:now>”
Lots of new terms
• Linked Data: connecting data through identifiers
• triples: <MJ> <born in> <Indiana>
• RDF: A way to describe content using identifiers
• SPARQL: A query language for triples
• ontology: A big vocabulary that defines URIs for classifying things and relationships
top related