Data

• Data is everywhere (personal, government, health, events..)
• Uncovering insights
• Predictions
• Making decisions (e.g., where to save energy)
• Smarter systems

Data: What is it good for?

Absolutely everything!

• Understanding human societies
• Health conditions
• Stable economies
• How do/should things work?

RDF Model

• Similar to Entity-Attribute-Value (EAV) data model e.g., Sarven.height = 1.65m
• To describe concepts and their relationships (many Graphs)
• Names for resources (URIs)

Human languages

How do we express ourselves?

• Sentences: subjects and predicates (verbs), and sometimes objects
• Body language meh ;)

Vocabularies

• Definitions for the relationship between things e.g.,Friend of a Friend (FOAF), Dublin Core Terms
• Decentralized invention (anyone can make theirs)

RDF Triples

    <Subject> <Predicate> <Object> .

• Different ways to write it
• Serializations: RDFa, Turtle, N-Triples, RDF/XML, JSON

N-Triples (also valid Turtle) example

• Sarven's height is 1.65m.

  <http://csarven.ca/#i> 
    <http://dbpedia.org/property/height>
      "1.65m" .
  

• Montreal is a city.

  <http://dbpedia.org/resource/Montreal> 
    <http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
      <http://dbpedia.org/ontology/City> .
  

RDFa example

• Sarven is 1.65m.

  <p about="http://csarven.ca/#i">
      Sarven is <span property="dbp:height">1.65m</span></p>
  

• Montreal is a city.

  <p about="dbr:Montreal">
     typeof="dbo:City">Montreal is a city.</p>
  

• Sarven is in Montreal.

  <p about="http://csarven.ca/#i">
      Sarven is in <a rel="foaf:based_near"
                      href="dbr:Montreal">Montreal</a>.</p>
  

RDF/XML example

• Montreal is a city.

  <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
    <rdf:Description rdf:about="http://dbpedia.org/resource/Montreal">
      <rdf:type rdf:resource="http://dbpedia.org/ontology/City">
    </rdf:Description>
  </rdf:RDF>
  

SPARQL

Query language for RDF

• Query for patterns instead of searching! e.g., What proteins are involved in signal transduction and are related to pyramidal neurons?

SPARQL

Query language for RDF

• Query for patterns instead of searching!

SPARQL query example

• Select a list of subjects that is a city.

      SELECT ?city
      WHERE {
          ?city a <http://dbpedia.org/ontology/City> .
      }
      

SPARQL query result example

SPARQL

Query language for RDF

• Query for patterns instead of searching!
• SPARQL endpoints (allow others to query your data)
• Federated queries (merge data w/ a single query)

SPARQL query: federated

• CONSTRUCT {
  ..
  }
  WHERE {
      { SERVICE <http://data.linkedmdb.org/sparql> {
              SELECT * WHERE { .. }
        }
      }
      UNION
      { SERVICE <http://dbpedia.org/sparql> {
              SELECT * WHERE { .. }
        }
      }
  }
  

Where to start?

• Ask good questions!
• Familiarize yourself with data
• Discover and browse data (e.g., see LOD coud)
• Check out data visualizations
• Consume and link to others

Make your data discoverable

• Name your resources and publish them
• VoID (describes linked datasets)
• Google Rich Snippets (uses RDFa)
• D2RQ (Relational DB to RDF mapping)

Tools

• Linked Data browsers (e.g., Tabulator)
• Visualizations (e.g., RDF -> DSPL Google Public Explorer)
• Raptor utils (command line)
• W3C validator
• Inspectors (Sindice), Mashups (Sig.ma)
• Google Refine + RDF extension
• Linked Data Pages (PHP framework)

Conclusions

• Distributed API out of the box!
• Data is connected across different sources
• Foundation for other things (reasoning?)
• Democratizing data for people
• No platform lock-in

Future work

• Authentication (WebID) and authorization
• Writing to Linked Data Web
• Web of Things, Augmented Reality
• Better user interfaces (a big must!)
• Making more data accessible
• Bridging disciplines