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LOD 4 ROD: Linked Open Data & Semantics for Rotterdam Open Data

Kathrin Dentler
k.dentler@vu.nl

Twitter:
@kathrinrin

Rotterdam
10. May 2011






Presentation available online at: http://www.few.vu.nl/~kdr250/lod4rod/

Linked (Open) Data

Linking data instead of documents (→ discoverable; typed links)

Ultimate goal: being able to query the web as a single global database

Easier integration of several datasets due to standardised data model & query language (otherwise, each hacker needs to write custom code to deal with each API separately)

Linked Open Data: 2007 - over 2 billion RDF (Resource Description Framework) triples, interlinked by over 2 million RDF links

Linked Open Data: 2008

Linked Open Data: 2009

Linked Open Data: 2010 - 25 billion RDF (Resource Description Framework) triples, interlinked by around 395 million RDF links

Tim Berners-Lee: 4 rules for putting data on the web

  1. Use URIs (Uniform Resource Identifiers) as names for things (e.g. http://dbpedia.org/page/Rotterdam
  2. Use HTTP URIs so that people can look up those names.
  3. When someone looks up a URI, provide useful information, using the standards (RDF, SPARQL)
  4. Include links to other URIs. so that they can discover more things. (e.g. owl:sameAs http://www.freebase.com/view/en/rotterdam; Freebase: "An entity graph of people, places and things, built by a community that loves open data." )

Linked (Open) Data / Semantic Web / Web 3.0

RDF: Resource Description Framework


RDF Serialization Formats

N3/Turtle

<http://www.Department0.University0.edu>
<http://www.lehigh.edu/~zhp2/2004/0401/univ-bench.owl#ub:subOrganizationOf>
<http://www.University0.edu> .

RDF/XML Abbreviation

<?xml version="1.0" encoding="UTF-8" ?>
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:ub="http://www.lehigh.edu/~zhp2/2004/0401/univ-bench.owl#">

<rdf:Description rdf:about="http://www.Department0.University0.edu">
  <ub:subOrganizationOf>
    <rdf:Description rdf:about="http://www.University0.edu" />
  </ub:subOrganizationOf>
</rdf:Description>
</rdf:RDF>

N-Triples

RDF/json (new W3C RDF WG)

RDFa

RDF Schema: RDF Vocabulary Description Language

SPARQL: Query Language for RDF

Example: The Data-gov Wiki Demo - Broadband Internet Use versus Total Internet Use - United States Households, 2009

SPARQL: Query Language for RDF

Example: Corresponding SPARQL query

PREFIX  d: <http://data-gov.tw.rpi.edu/vocab/p/10040/>
SELECT  ?state ?urban_home_broadband ?urban_home_total ?rural_home_broadband 
        ?rural_home_total
        
WHERE { 
  graph <http://data-gov.tw.rpi.edu/vocab/Dataset_10040>{
    ?s d:state ?state .
    ?s d:urban_internet_use_in_the_home_broadband_no ?urban_home_broadband .
    ?s d:urban_internet_use_in_the_home_urban_total_no ?urban_home_total .
    ?s d:rural_internet_use_in_the_home_broadband_no ?rural_home_broadband .
    ?s d:rural_internet_use_in_the_home_total_no ?rural_home_total .
        
    FILTER (?state != "TOTAL HOUSEHOLDS")
  }
} 
ORDER BY ?state

Applications

DBpedia Mobile (http://wiki.dbpedia.org/DBpediaMobile), based on DBpedia: structured information from Wikipedia made available on the Web (http://dbpedia.org/About):

Amsterdam fire brigade routing: governmental linked data on Open Street Map (http://blog.okfn.org/2010/10/25/getting-started-with-governmental-linked-open-data)

Pointers

Thanks!




Questions?


Comments?


Ideas?