The document discusses a real-world implementation of linked data by Dimitri van Hees. It describes converting data from different sources like Facebook and LinkedIn into JSON, JSON-LD, and RDF triples and storing them in a triplestore. It also discusses using a SPARQL endpoint and API to access and link the data while addressing the needs of different communities. The implementation uses technologies like AngularJS, RAML, MongoDB, AllegroGraph and Symfony2 to build a dashboard bringing together user data from various sources into linked data formats.

1. A Real-World Implementation
of Linked Data
Dimitri van Hees, APIcon UK 2014

2. About me
• Technical Architect
• Data Specialist
• Freshheads BV
• API supporter

3. About me
“The only bad thing about API is
that it’s the inverse of IPA”

4. About me
• Brewmaster
• MQTT API driven brewery
“De Brouwtoren”

6. 0641011744
• Number
• Registration number
• Telephone number
• Flight number
• Bank account

7. 0641011744
• Number
• Registration number
• Telephone number
• Flight number
• Bank account

8. Dimitri
• String
• Word
• Place
• Dimitri van Hees
• Dimitri the Clown

9. Dimitri
• String
• Word
• Place
• Dimitri van Hees
• Dimitri the Clown

10. Linked Data
• Alias The Semantic Web, Web 3.0
• Defines what the data means (government)
• Provides links to external resources (apps)
• Adds possibility to query multiple datasets
(marketing)

11. Five stars of Sir Tim Berners-Lee

12. ★
“Make your stuff available on the
Web (whatever format) under an
open license”

13. ★ ★
“Make it available as structured
data (e.g., Excel instead of image
scan of a table)”

14. ★ ★ ★
“Use non-proprietary formats
(e.g., CSV instead of Excel)”

15. ★ ★ ★ ★
“Use URIs to denote things, so
that people can point at your
stuff (RDF)”

16. ★ ★ ★ ★ ★
“Link your data to other data to
provide context (Linked Data)”

17. Dutch Linked Open Data Program
• Universities
• Governments
• Semi-governments
• Freshheads (me)
• Case 5: Linked Data for developers

18. Data landscape
• Open Data community
• Linked Open Data community
• API community
• Data publishers
• Data consumers

19. Data consumers
• Provide us the developer-friendliest way to access your
data and we MIGHT use it

20. Data publishers
• HOW should we publish our data?
• What are the COSTS of doing it that way?
• What are the BENEFITS of doing it that way?

21. Open Data community
• We don’t care HOW the data is published
• We only care IF the data is open

22. API community
• Every publisher SHOULD provide RESTful JSON API’s
• Because every consumer KNOWS RESTful JSON API’s
• We DON’T believe in Linked Data

23. Linked Open Data community
• Every publisher SHOULD provide five star data
• Every consumer SHOULD learn SPARQL*
• So we DON’T need API’s
*Linked Data query language

24. WTF is SPARQL?

25. Benefits
According to EU studies the amount of apps being
developed with Linked Open Government Data is
negligible.
https://joinup.ec.europa.eu/sites/default/files/85/31
/25/Study_on_business_models_for_Linked_Open_
Government_Data_BM4LOGD_v1.00.pdf

26. Costs
• Knowledge investment (unknown technology)
• Technical investment (hosting infrastructure)
• Time investment (change management)
• Low ROI

27. “The quality of many datasets is
AT MOST three stars”

28. Five stars of Sir Tim Berners-Lee

30. ★ ★ ★ ★
“Provide online access via
webservices so developers can
use your stuff the way they are
used to (RESTful JSON API)”

31. ★ ★ ★ ★ ★
“Add context to your API so it can be
linked to other datasets, developers
know what the data means and LOD
guys can convert it to triples, store it
in triplestores and use SPARQL if they
want to (JSON-LD)”

32. ★ ★ ★ ★ ★ ★

33. Case
“Build a dashboard with which we
are capable to better learn about our
fans and customers so that we can
take action on that knowledge to win
sympathy for our brand”

34. Data sources
• Facebook (likes, favorites, education, profile)
• LinkedIn (skills, education, jobs, profile)
• Twitter profiles
• Website profiles

35. Challenges
• Internal
• External
• Technical
• Agile/rapid development

36. JSON
JSON-LD
Triples

37. JSON
{
"id": 43274,
"name": "Dimitri van Hees",
"gender": "m",
"birthDate": "1984-03-14",
"birthPlace": "Nijmegen",
"facebookLikes": [
69116329538,
272002449634285,
114690771875816
]
}

38. JSON-LD Context
{
"id": "@id",
"name": "http://xmlns.com/foaf/0.1/name",
"gender": "http://xmlns.com/foaf/0.1/gender",
"birthDate": "http://schema.org/birthDate",
"birthPlace": "http://dbpedia.org/ontology/birthPlace",
"facebookLike": "http://xmlns.com/foaf/0.1/interest"
}

39. JSON-LD Context
{
"foaf": "http://xmlns.com/foaf/0.1/",
"schema": "http://schema.org/",
"dbo": "http://dbpedia.org/ontology/",
"id": "@id",
"name": "foaf:name",
"gender": "foaf:gender",
"birthDate": "schema:birthDate",
"birthPlace": "dbo:birthPlace",
"facebookLikes": "foaf:interest"
}

40. JSON-LD
{
"id": "http://example.com/customers/43274",
"type": "schema:Person",
"name": "Dimitri van Hees",
"gender": "m",
"birthDate": "1984-03-14",
"birthPlace": {
"id": "http://dbpedia.org/resource/Nijmegen", "type": "schema:City"
},
"facebookLikes": [
{ "id": "http://graph.facebook.com/69116329538", "type": "schema:MusicGroup“ },
{ "id": "http://graph.facebook.com/272002449634285", "type": "schema:TVSeries“ },
{ "id": "http://graph.facebook.com/114690771875816", "type": "schema:City“ }
]
}

41. JSON-LD
{
"id": "http://example.com/customers/43274",
"type": "schema:Person",
"name": "Dimitri van Hees",
"gender": "m",
"birthDate": "1984-03-14",
"birthPlace": {
"id": "http://dbpedia.org/resource/Nijmegen", "type": "schema:City"
},
"facebookLikes": [
{ "id": "http://dbpedia.org/resource/The_Beatles", "type": "schema:MusicGroup“ },
{ "id": "http://dbpedia.org/resource/Monty_Python", "type": "schema:TVSeries“ },
{ "id": "http://dbpedia.org/resource/Nijmegen", "type": "schema:City“ }
]
}

42. Triples
Subject Predicate Object
http://example.com/custom
http://xmlns.com/foaf/0.1/
ers/43274
name
"Dimitri van Hees"
http://example.com/custom
ers/43274
http://xmlns.com/foaf/0.1/g
ender
"m"
http://example.com/custom
ers/43274
http://dbpedia.org/ontolog
y/birthPlace
http://dbpedia.org/resource
/Nijmegen
http://example.com/custom
ers/43274
http://xmlns.com/foaf/0.1/i
nterest
http://dbpedia.org/resource
/The_Beatles
http://example.com/custom
ers/43274
http://xmlns.com/foaf/0.1/i
nterest
http://dbpedia.org/resource
/Monty_Python
http://example.com/custom
ers/43274
http://xmlns.com/foaf/0.1/i
nterest
http://dbpedia.org/resource
/Nijmegen

43. Triplestore: AllegroGraph
• Database for triples
• Free up to 5.000.000 triples
• SPARQL 1.1 support
• REST API
• Local installation (privacy)
• Help from LOD community

46. SPARQL
• SPARQL Protocal And RDF Query Language
• SPARQL Endpoint !== API
• SPARQL looks like SQL but isn’t

47. SPARQL
• SPARQL Protocal And RDF Query Language
• SPARQL Endpoint !== API
• SPARQL looks like SQL but isn’t
• Just like Dutch looks like German but isn’t… Again,
it’s all about context!

48. SPARQL 1.1: federated queries
• Which people older than 40 live in a capital?
• Which people live in a city with more than 600.000
inhabitants?
• Which people live in another country than they
were born and like The Beatles?
• Which people like a movie from a certain director?
• Etc.

49. SPARQL

50. In depth view, statistics

51. One API, three purposes
• Conversion to Linked Data
• Export possibilities using content-negotiation:
JSON, JSON-LD, CSV, Triples
• Orchestration layer for the app

52. Step 1: JSON support

53. Step 2: JSON-LD support

54. Step 3: Triples support

55. Used technologies
• AngularJS frontend
• RAML modeling language
• MongoDB raw data store
• AllegroGraph triplestore
• Symfony2 PHP API

56. “The Semantic Web does exist and goes
hand in hand with API’s. Using six stars
instead of five, API’s are actually part of
the deployment scheme while making
live easier for data publishers and data
consumers. Let’s bridge the gap, bring
the best of both worlds, and let’s
change the web together.”

57. Thank you!
• Twitter: http://twitter.com/dvh
• E-mail: dimitri@freshheads.com
• GitHub: http://github.com/dvh
• LinkedIn: https://linkedin.com/in/dimitrivanhees

58. Thank you!
• Twitter: http://twitter.com/dvh
• E-mail: dimitri@freshheads.com
• GitHub: http://github.com/dvh
• LinkedIn: https://linkedin.com/in/dimitrivanhees
• Brewery: http://facebook.com/brouwtoren