The Web of the Future: Introduction to the Semantic Web - Bulgaria PHP 2019

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 query seemingly incompatible data sets as if they were one and letting a computer draw logical (and perhaps surprising) conclusions for us.

Contains: ‘retro’ technology, linked data, fundamental properties of the web, and Donald Trump’s opinion on PHP frameworks.

Transcript

1. The Web of the Future: Introduction to the Semantic Web @arnoutboks Arnout Boks #bgphp19 09-11-2019
2. @arnoutboks #bgphp19 What this talk is NOT about…
3. @arnoutboks #bgphp19 Finding info on the web An example
4. @arnoutboks #bgphp19 “Web 1.0”
5. @arnoutboks #bgphp19 “Web 1.0”
6. @arnoutboks #bgphp19 “Web 1.0”
7. @arnoutboks #bgphp19 Web 1.0 Web of Documents for human consumption
8. @arnoutboks #bgphp19 “Web 2.0” Feed of events • iCalendar or vCalendar? • Different types of events?
9. @arnoutboks #bgphp19 “Web 2.0” Weather forecast API • XML or JSON? • Which fields and properties? • Which units?
10. @arnoutboks #bgphp19 Web 2.0 Web of (individual) API’s for consumption by specialized software
11. @arnoutboks #bgphp19 Semantic web • Question to agent (e.g. Siri, Google Assistant) • Agent searches across different sources • Agent combines data • Agent answers question
12. @arnoutboks #bgphp19 Semantic Web (“Web 3.0”?) Web of Linked Data for consumption by intelligent agents/PA’s
13. @arnoutboks #bgphp19 Revolutionary? Term coined by Tim Berners-Lee in 2001
14. @arnoutboks #bgphp19 Revolutionary? Based on W3C-standards • RDF (1998) • RDFS (1998) • SPARQL (2008) • OWL (2004) • …
15. @arnoutboks #bgphp19 RDF Cornerstone of the Semantic Web Resource Description Framework Cornerstone of the Semantic Web
16. @arnoutboks #bgphp19 Records statements about things
17. @arnoutboks #bgphp19 RDF allows reading, merging, relaying and inferring statements without fully understanding them
18. @arnoutboks #bgphp19 RDF (triples) Subject Predicate Object
19. @arnoutboks #bgphp19 RDF (triples) Subject Predicate Object Arnout worksAt Moxio
20. @arnoutboks #bgphp19 RDF (triples) Subject Predicate Object Arnout worksAt Moxio Arnout twitterHandle “@arnoutboks” Arnout livesIn Delft Delft cityIn The Netherlands Moxio basedIn Delft
21. @arnoutboks #bgphp19 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
22. @arnoutboks #bgphp19 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”
23. @arnoutboks #bgphp19 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”
24. @arnoutboks #bgphp19 Merging RDF (graph) Arnout Moxio Delft @arnoutboks worksAt basedIn The Netherlands Amsterdam hasCapital 17.000.000 population
25. @arnoutboks #bgphp19 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 .
26. @arnoutboks #bgphp19 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>
27. @arnoutboks #bgphp19 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" } ] }, ... ]
28. @arnoutboks #bgphp19 RDF is an abstract data model with different serialization formats
29. @arnoutboks #bgphp19 Identity Because there are multiple things named “Amsterdam”
30. @arnoutboks #bgphp19 Identity Subject Predicate Object Amsterdam numberOfGuns “42” Amsterdam status Wrecked National Maritime Museum (“Scheepvaartmuseum”)
31. @arnoutboks #bgphp19 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
32. @arnoutboks #bgphp19 Identity The Netherlands Amsterdam hasCapital 17.000.000 population 42 Wrecked
33. @arnoutboks #bgphp19 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
34. @arnoutboks #bgphp19 Prefixes & QNames lonelyplanet:Amsterdam === https://www.lonelyplanet.com/Amsterdam QName URI local name local name namespace prefix
35. @arnoutboks #bgphp19 Prefixes & QNames National Maritime Museum (“Scheepvaartmuseum”) nmm:Amsterdam nmm:numberOfGuns Lonely Planet lonelyplanet:Amsterdam lonelyplanet:hasCapital
36. @arnoutboks #bgphp19 Three fundamental laws of the (Semantic) Web
37. @arnoutboks #bgphp19 Different name, different concept? lonelyplanet-en:Brussels lonelyplanet-nl:Brussel lonelyplanet-bg:Брюксел lonelyplanet-zh:布魯塞爾
38. @arnoutboks #bgphp19 Different name, different concept? mi6:007 mi6:JamesBond
39. @arnoutboks #bgphp19 Nonunique Naming Assumption Different names do not imply different concepts
40. @arnoutboks #bgphp19 Truth & authority Subject Predicate Object whitehouse:Obama nsa:tapped whitehouse:Trump Donald Trump
41. @arnoutboks #bgphp19 Truth & authority Subject Predicate Object php-fig:CakePHP fw:isBetterThan php-fig:Symfony Donald Trump
42. @arnoutboks #bgphp19 The AAA Slogan “[On the web] Anyone can say Anything about Any topic”
43. @arnoutboks #bgphp19 (this slide intentionally left blank)
44. @arnoutboks #bgphp19 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
45. @arnoutboks #bgphp19 Open World Assumption We never have all information
46. @arnoutboks #bgphp19 SPARQL Query language for Semantic Web data
47. @arnoutboks #bgphp19 Triple Store Database for RDF triples
48. @arnoutboks #bgphp19 SPARQL SELECT ?employee ?company WHERE { ?employee :worksAt ?company . ?company :basedIn :Delft . }
49. @arnoutboks #bgphp19 SPARQL SELECT ?employee ?company WHERE { ?employee :worksAt ?company . ?company :basedIn :Delft . } ?employee ?company :Arnout :Moxio
50. @arnoutboks #bgphp19 SPARQL SELECT ?employee ?company ?city WHERE { ?employee :worksAt ?company . ?company :basedIn ?city . ?employee :livesIn ?city . } ?employee ?company ?city :Arnout :Moxio :Delft
51. @arnoutboks #bgphp19 Online SPARQL endpoints http://dbpedia.org/sparql
52. @arnoutboks #bgphp19 Online SPARQL endpoints
53. @arnoutboks #bgphp19 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)
54. @arnoutboks #bgphp19 Online SPARQL endpoints
55. @arnoutboks #bgphp19 Online SPARQL endpoints PREFIX dbo: <http://dbpedia.org/ontology/> PREFIX dbr: <http://dbpedia.org/resource/> SELECT ?ancestor WHERE { dbr:Willem-Alexander_of_the_Netherlands dbo:parent+ ?ancestor . }
56. @arnoutboks #bgphp19 RDF Schema Schema language for Semantic Web data
57. @arnoutboks #bgphp19 RDF Schema (RDFS) Describes the structure of RDF-data… in RDF • Classes • Properties • Domain and range of properties • Inheritance of classes • ‘Inheritance’ of properties
58. @arnoutboks #bgphp19 RDF Schema (RDFS) Subject Predicate Object :DonaldTrump :isFatherOf :IvankaTrump
59. @arnoutboks #bgphp19 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
60. @arnoutboks #bgphp19 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
61. @arnoutboks #bgphp19 Inference Reasoner (asserted) triples inferred/virtual triples
62. @arnoutboks #bgphp19 Inference Reasoner (asserted) triples inferred/virtual triples
63. @arnoutboks #bgphp19 SPARQL & Inference SELECT ?person WHERE { ?person rdf:type :Person . } ?person :IvankaTrump :DonaldTrump
64. @arnoutboks #bgphp19 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
65. @arnoutboks #bgphp19 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
66. @arnoutboks #bgphp19 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
67. @arnoutboks #bgphp19 Query different sources as if they were one
68. @arnoutboks #bgphp19 RDF Schema vs. JSON/XML Schema Subject Predicate Object mi6:JamesBond rdf:type mi6:SecretAgent mi6:JamesBond nmm:numberOfGuns “1” MI6 files
69. @arnoutboks #bgphp19 RDF Schema vs. JSON/XML Schema Subject Predicate Object mi6:JamesBond rdf:type mi6:SecretAgent mi6:JamesBond nmm:numberOfGuns “1” MI6 files
70. @arnoutboks #bgphp19 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”)
71. @arnoutboks #bgphp19 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
72. @arnoutboks #bgphp19 RDF Schema vs. JSON/XML Schema
73. @arnoutboks #bgphp19 RDF Schema will never consider data to be invalid
74. @arnoutboks #bgphp19 Web Ontology Language (OWL) Even smarter inferencing Web Ontology Language (OWL) Even smarter inferencing
75. @arnoutboks #bgphp19 OWL OWL ≈ RDFS++
76. @arnoutboks #bgphp19 OWL Power comes at a price…
77. @arnoutboks #bgphp19 OWL: Inverse properties Subject Predicate Object :DonaldTrump :isParentOf :IvankaTrump :isParentOf owl:inverseOf :isChildOf :IvankaTrump :isChildOf :DonaldTrump
78. @arnoutboks #bgphp19 OWL: Symmetric properties Subject Predicate Object :DonaldTrump :isMarriedTo :MelaniaTrump :isMarriedTo rdf:type owl:SymmetricProperty :MelaniaTrump :isMarriedTo :DonaldTrump
79. @arnoutboks #bgphp19 OWL: Equality Subject Predicate Object :DonaldTrump :isMarriedTo :MelaniaTrump :DonaldTrump owl:sameAs :TheDon :TheDon :isMarriedTo :MelaniaTrump
80. @arnoutboks #bgphp19 OWL: Functional properties Subject Predicate Object :IvankaTrump :hasFather :DonaldTrump :IvankaTrump :hasFather :TheDon :hasFather rdf:type owl:FunctionalProperty :TheDon owl:sameAs :DonaldTrump
81. @arnoutboks #bgphp19 Inconsistency Subject Predicate Object :IvankaTrump :hasFather :DonaldTrump :IvankaTrump :hasFather :TheDon :hasFather rdf:type owl:FunctionalProperty :TheDon owl:differentFrom :DonaldTrump
82. @arnoutboks #bgphp19 Inconsistency
83. @arnoutboks #bgphp19 Inconsistency
84. @arnoutboks #bgphp19 It’s okay to be inconsistent… (remember the AAA slogan)
85. @arnoutboks #bgphp19 It’s okay to be inconsistent… (remember the AAA slogan) …but the reasoner won’t help you anymore
86. @arnoutboks #bgphp19 Self-test Subject Predicate Object :George :hasChild :Michelle :George :hasChild :James How many children does George have?
87. @arnoutboks #bgphp19 Further steps Get going with the Semantic Web
88. @arnoutboks #bgphp19 Leveraging the Semantic Web Network effect
89. @arnoutboks #bgphp19 Leveraging the Semantic Web Only useful when multiple parties speak the same ‘language’
90. @arnoutboks #bgphp19 Align with existing vocabularies
91. @arnoutboks #bgphp19 Leveraging the Semantic Web Mapping between vocabularies: • rdfs:subclassOf • rdfs:subpropertyOf • owl:inverseOf • owl:sameAs
92. @arnoutboks #bgphp19 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
93. @arnoutboks #bgphp19 Resources • Apache Jena (includes Fuseki triple store) • 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
94. @arnoutboks #bgphp19 Resources
95. @arnoutboks #bgphp19 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/
96. @arnoutboks #bgphp19 Feedback & Questions Please leave your feedback on joind.in: https://joind.in/talk/de222 @arnoutboks https://aboks.github.io Arnout Boks
97. @arnoutboks #bgphp19 Image Credits • https://www.flickr.com/photos/lex-photographic/32521124574 • https://www.flickr.com/photos/rwoan/34676675925 • 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://pixabay.com/nl/nuance-stalen-kleur-pantone-1074766/ • https://www.flickr.com/photos/borkurdotnet/9682277597