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Introduction to the Semantic Web - phpCE 2017

Arnout Boks
November 04, 2017

Introduction to the Semantic Web - phpCE 2017

Video recording: https://www.youtube.com/watch?v=WUOuKB0Ji10.
Joind.in: https://joind.in/talk/eb31e

What if we could evolve our web of individual documents and data to a web of interlinked knowledge, a web where machines can automatically combine data from multiple sources and draw conclusions from it?
The Semantic Web technologies from W3C enable us to make sense of the data wilderness on the web and unlock the full potential of the data treasures hidden in it. In this talk, we will see how RDF enables us to formally describe the meaning of data and how such data can be queried with SPARQL. We will look at how OWL lets us make more expressive statements about the world, so that a computer can logically reason about it and infer new information. We will demonstrate these technologies by showing how they can be used to combine data sets in different formats as if they were one and letting a computer draw logical (and perhaps surprising) conclusions for us.

Arnout Boks

November 04, 2017
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  1. @arnoutboks #phpce17 “Web 2.0” Feed of events • iCalendar or

    vCalendar? • Different types of events?
  2. @arnoutboks #phpce17 “Web 2.0” Weather forecast API • XML or

    JSON? • Which fields and properties? • Which units?
  3. @arnoutboks #phpce17 Semantic web • Question to agent (e.g. Siri)

    • Agent searches across different sources • Agent combines data • Agent answers question
  4. @arnoutboks #phpce17 Semantic Web (“Web 3.0”?) Web of Linked Data

    for consumption by intelligent agents/PA’s
  5. @arnoutboks #phpce17 Revolutionary? Based on W3C-standards • RDF (1998) •

    RDFS (1998) • SPARQL (2008) • OWL (2004) • …
  6. @arnoutboks #phpce17 RDF (triples) Subject Predicate Object Arnout worksAt Moxio

    Arnout twitterHandle “@arnoutboks” Arnout livesIn Delft Delft cityIn The Netherlands Moxio basedIn Delft
  7. @arnoutboks #phpce17 RDF (graph) Arnout Moxio Delft @arnoutboks worksAt basedIn

    The Netherlands Subject Predicate Object Arnout worksAt Moxio Arnout twitterHandle “@arnoutboks” Arnout livesIn Delft Delft cityIn The Netherlands Moxio basedIn Delft
  8. @arnoutboks #phpce17 Merging RDF (triples) Subject Predicate Object Arnout worksAt

    Moxio Arnout twitterHandle “@arnoutboks” Arnout livesIn Delft Delft cityIn The Netherlands Moxio basedIn Delft Subject Predicate Object The Netherlands hasCapital Amsterdam The Netherlands population “17.000.000”
  9. @arnoutboks #phpce17 Merging RDF (triples) Subject Predicate Object Arnout worksAt

    Moxio Arnout twitterHandle “@arnoutboks” Arnout livesIn Delft Delft cityIn The Netherlands Moxio basedIn Delft The Netherlands hasCapital Amsterdam The Netherlands population “17.000.000”
  10. @arnoutboks #phpce17 Merging RDF (graph) Arnout Moxio Delft @arnoutboks worksAt

    basedIn The Netherlands Amsterdam hasCapital 17.000.000 population
  11. @arnoutboks #phpce17 Serializing RDF: Turtle @prefix : <http://www.example.com/#> . @prefix

    rdf: <http://www.w3.org/1999/02/22-rdf-syntax- ns#> . @prefix xsd: <http://www.w3.org/2001/XMLSchema#> . @base <http://www.example.com/> . :Arnout :livesIn :Delft ; :worksAt :Moxio ; :twitterHandle "@arnoutboks"^^xsd:string . :Delft :cityIn :The_Netherlands . :Moxio :basedIn :Delft .
  12. @arnoutboks #phpce17 Serializing RDF: RDF/XML <?xml version="1.0"?> <rdf:RDF xmlns="http://www.example.com/#" <!--

    ... -->> <rdf:Description rdf:about="http://www.example.com/#Arnout"> <twitterHandle rdf:datatype="http://www.w3.org/2001/XMLSchema#string">@a rnoutboks</twitterHandle> <worksAt rdf:resource="http://www.example.com/#Moxio"/> <livesIn rdf:resource="http://www.example.com/#Delft"/> </rdf:Description> <!-- ... --> </rdf:RDF>
  13. @arnoutboks #phpce17 Serializing RDF: JSON-LD [ { "@id" : "http://www.example.com/#Arnout",

    "http://www.example.com/#livesIn" : [ { "@id" : "http://www.example.com/#Delft" } ], "http://www.example.com/#twitterHandle" : [ { "@value" : "@arnoutboks" } ], "http://www.example.com/#worksAt" : [ { "@id" : "http://www.example.com/#Moxio" } ] }, ... ]
  14. @arnoutboks #phpce17 Identity Subject Predicate Object Amsterdam numberOfGuns “42” Amsterdam

    status Wrecked National Maritime Museum (“Scheepvaartmuseum”)
  15. @arnoutboks #phpce17 Identity Subject Predicate Object Amsterdam numberOfGuns “42” Amsterdam

    status Wrecked Subject Predicate Object The Netherlands hasCapital Amsterdam The Netherlands population “17.000.000” National Maritime Museum (“Scheepvaartmuseum”) Lonely Planet
  16. @arnoutboks #phpce17 URI’s for namespacing National Maritime Museum (“Scheepvaartmuseum”) https://www.hetscheepvaartmuseum.nl/ships/Amsterdam

    https://www.hetscheepvaartmuseum.nl/ships/numberOfGuns Lonely Planet https://www.lonelyplanet.com/Amsterdam https://www.lonelyplanet.com/hasCapital
  17. @arnoutboks #phpce17 Prefixes & QNames National Maritime Museum (“Scheepvaartmuseum”) nmm:Amsterdam

    nmm:numberOfGuns Lonely Planet lonelyplanet:Amsterdam lonelyplanet:hasCapital
  18. @arnoutboks #phpce17 Absence of information Subject Predicate Object whitehouse:Trump fw:knows

    php-fig:Symfony whitehouse:Trump fw:knows php-fig:CakePHP whitehouse:Trump fw:knows php-fig:CodeIgniter
  19. @arnoutboks #phpce17 SPARQL SELECT ?employee ?company WHERE { ?employee :worksAt

    ?company . ?company :basedIn :Delft . } ?employee ?company :Arnout :Moxio
  20. @arnoutboks #phpce17 SPARQL SELECT ?employee ?company ?city WHERE { ?employee

    :worksAt ?company . ?company :basedIn ?city . ?employee :livesIn ?city . } ?employee ?company ?city :Arnout :Moxio :Delft
  21. @arnoutboks #phpce17 Online SPARQL endpoints PREFIX dbo: <http://dbpedia.org/ontology/> PREFIX dbr:

    <http://dbpedia.org/resource/> SELECT ?song ?runtime WHERE { ?song dbo:artist dbr:The_Beatles . ?song dbo:runtime ?runtime . ?song rdf:type dbo:Song . } ORDER BY DESC (?runtime)
  22. @arnoutboks #phpce17 RDF Schema (RDFS) Describes the structure of RDF-data…

    in RDF • Classes • Properties • Domain and range of properties • Inheritance of classes • ‘Inheritance’ of properties
  23. @arnoutboks #phpce17 RDF Schema (RDFS) Subject Predicate Object :DonaldTrump :isFatherOf

    :IvankaTrump :isFatherOf rdfs:range :Person :isFatherOf rdfs:domain :Father :Father rdfs:subclassOf :Parent :Parent rdfs:subclassOf :Person :isFatherOf rdfs:subpropertyOf :isParentOf
  24. @arnoutboks #phpce17 RDF Schema & Inference Subject Predicate Object :DonaldTrump

    :isFatherOf :IvankaTrump :isFatherOf rdfs:range :Person :isFatherOf rdfs:domain :Father :Father rdfs:subclassOf :Parent :Parent rdfs:subclassOf :Person :isFatherOf rdfs:subpropertyOf :isParentOf :IvankaTrump rdf:type :Person :DonaldTrump rdf:type :Father :DonaldTrump rdf:type :Parent :DonaldTrump rdf:type :Person :DonaldTrump :isParentOf :IvankaTrump
  25. @arnoutboks #phpce17 SPARQL & Inference SELECT ?person WHERE { ?person

    rdf:type :Person . } ?person :IvankaTrump :DonaldTrump
  26. @arnoutboks #phpce17 Combining data using inference Subject Predicate Object a:DonaldTrump

    rdf:type a:Person Datasource A Subject Predicate Object b:MelaniaTrump rdf:type b:Human Datasource B
  27. @arnoutboks #phpce17 Combining data using inference Subject Predicate Object a:DonaldTrump

    rdf:type a:Person Datasource A Subject Predicate Object b:MelaniaTrump rdf:type b:Human Datasource B Subject Predicate Object a:Person rdfs:subclassOf b:Human b:Human rdfs:subclassOf a:Person Mapping rules
  28. @arnoutboks #phpce17 Combining data using inference Subject Predicate Object a:DonaldTrump

    rdf:type a:Person b:MelaniaTrump rdf:type b:Human a:Person rdfs:subclassOf b:Human b:Human rdfs:subclassOf a:Person a:DonaldTrump rdf:type b:Human b:MelaniaTrump rdf:type a:Person
  29. @arnoutboks #phpce17 RDF Schema vs. JSON/XML Schema Subject Predicate Object

    mi6:JamesBond rdf:type mi6:SecretAgent mi6:JamesBond nmm:numberOfGuns “1” MI6 files
  30. @arnoutboks #phpce17 RDF Schema vs. JSON/XML Schema Subject Predicate Object

    mi6:JamesBond rdf:type mi6:SecretAgent mi6:JamesBond nmm:numberOfGuns “1” MI6 files
  31. @arnoutboks #phpce17 RDF Schema vs. JSON/XML Schema Subject Predicate Object

    mi6:JamesBond rdf:type mi6:SecretAgent mi6:JamesBond nmm:numberOfGuns “1” MI6 files Subject Predicate Object nmm:numberOfGuns rdf:domain nmm:Ship National Maritime Museum (“Scheepvaartmuseum”)
  32. @arnoutboks #phpce17 RDF Schema vs. JSON/XML Schema Subject Predicate Object

    mi6:JamesBond rdf:type mi6:SecretAgent mi6:JamesBond nmm:numberOfGuns “1” nmm:numberOfGuns rdf:domain nmm:Ship mi6:JamesBond rdf:type nmm:Ship
  33. @arnoutboks #phpce17 OWL: Inverse properties Subject Predicate Object :DonaldTrump :isParentOf

    :IvankaTrump :isParentOf owl:inverseOf :isChildOf :IvankaTrump :isChildOf :DonaldTrump
  34. @arnoutboks #phpce17 OWL: Symmetric properties Subject Predicate Object :DonaldTrump :isMarriedTo

    :MelaniaTrump :isMarriedTo rdf:type owl:SymmetricProperty :MelaniaTrump :isMarriedTo :DonaldTrump
  35. @arnoutboks #phpce17 OWL: Equality Subject Predicate Object :DonaldTrump :isMarriedTo :MelaniaTrump

    :DonaldTrump owl:sameAs :TheDon :TheDon :isMarriedTo :MelaniaTrump
  36. @arnoutboks #phpce17 OWL: Functional properties Subject Predicate Object :IvankaTrump :hasFather

    :DonaldTrump :IvankaTrump :hasFather :TheDon :hasFather rdf:type owl:FunctionalProperty :TheDon owl:sameAs :DonaldTrump
  37. @arnoutboks #phpce17 Inconsistency Subject Predicate Object :IvankaTrump :hasFather :DonaldTrump :IvankaTrump

    :hasFather :TheDon :hasFather rdf:type owl:FunctionalProperty :TheDon owl:differentFrom :DonaldTrump
  38. @arnoutboks #phpce17 It’s okay to be inconsistent… (remember the AAA

    slogan) …but the reasoner won’t help you anymore
  39. @arnoutboks #phpce17 Leveraging the Semantic Web Mapping between vocabularies: •

    rdfs:subclassOf • rdfs:subpropertyOf • owl:inverseOf • owl:sameAs
  40. @arnoutboks #phpce17 Existing vocabularies • Dublin Core • Metadata about

    publications and authors • Friend of a Friend • People, connections, social networks • GoodRelations • Products, prices, eCommerce • CB-NL • Construction, infrastructure, spatial planning • QUDT • Quantities, units, dimensions, conversions
  41. @arnoutboks #phpce17 Resources • Apache Jena • Semantic web framework/tools

    (written in Java) • easyrdf/easyrdf • RDF parser/writer for PHP • semsol/arc2 • PHP RDF library and MySQL-based triple store • FaCT++, HermiT & Pellet • Open source OWL reasoners • Protégé • RDF/OWL IDE with various reasoner plugins
  42. @arnoutboks #phpce17 Resources • https://www.w3.org/2013/data/ • https://www.w3.org/2001/sw/wiki/ • https://www.w3.org/TR/rdf11-primer/ •

    https://www.w3.org/TR/owl2-primer/ • https://www.w3.org/TR/sparql11-query/ • http://wiki.dbpedia.org/OnlineAccess • https://www.data.gov/ • http://lod-cloud.net/
  43. @arnoutboks #phpce17 Image Credits • https://www.flickr.com/photos/lex-photographic/32521124574 • https://www.flickr.com/photos/flamesworddragon/19686463141 • https://www.flickr.com/photos/littlehuw/15236543728

    • https://www.flickr.com/photos/crdominguez/422517106 • https://www.flickr.com/photos/pamwood707/5646757752 • https://www.flickr.com/photos/blair25/3240686470 • https://www.flickr.com/photos/tylerbeaulawrence/15167523690 • https://www.flickr.com/photos/23975018@N04/3675503072 • https://www.flickr.com/photos/borkurdotnet/9682277597