1. An
Introduction
to
Linked Data
Part 2 of 5 David Hyland-Wood
Data Modeling University of Mary Washington
Monday, May 16, 2011

2. Data modeling
without context
Monday, May 16, 2011

3. Modeling without Context
Monday, May 16, 2011

4. Modeling without Context
• Model the Real World
Monday, May 16, 2011

5. Modeling without Context
• Model the Real World
• Look for objects of interest
Monday, May 16, 2011

6. Modeling without Context
• Model the Real World
• Look for objects of interest
• Put aside the immediate needs of any
application
Monday, May 16, 2011

7. Modeling without Context
• Model the Real World
• Look for objects of interest
• Put aside the immediate needs of any
application
• Investigate how others are already
modeling similar or related data
Monday, May 16, 2011

8. Modeling without Context
• Model the Real World
• Look for objects of interest
• Put aside the immediate needs of any
application
• Investigate how others are already
modeling similar or related data
• These techniques allow for re-use and
merging
Monday, May 16, 2011

9. Modeling without Context
Monday, May 16, 2011

10. Modeling without Context
• Look for duplication (normalise)
Monday, May 16, 2011

11. Modeling without Context
• Look for duplication (normalise)
• Think about time and events, as well as
things
Monday, May 16, 2011

12. Modeling without Context
• Look for duplication (normalise)
• Think about time and events, as well as
things
• Consider how the data will change over
time
Monday, May 16, 2011

13. Modeling without Context
• Look for duplication (normalise)
• Think about time and events, as well as
things
• Consider how the data will change over
time
• Separate real-world (non-information
resources) and online (information
resources)
Monday, May 16, 2011

14. Objects of Interest
Apollo 11 Command and crew
Buzz Aldrin
Service Module
Monday, May 16, 2011

15. Objects of Interest
Apollo 11 Command and crew
Buzz Buzz Aldrin
Aldrin
Service Module
Monday, May 16, 2011

16. Objects of Interest
20 January 1930
Person
born
a
Apollo 11 Command and crew
Buzz Buzz Aldrin
Aldrin
Service Module
Monday, May 16, 2011

17. Objects of Interest
20 January 1930
Person
born
a
Apollo 11 Command and crew
Buzz Aldrin
Service Module
name
Buzz Aldrin
Monday, May 16, 2011

18. Apollo 11 Command and launchsite
Cape Canaveral
Service Module
name name
Apollo 11 Command and Service Module Cape Canaveral, United States
launched
16 July 1969
mass
28801.0
a
Spacecraft
Monday, May 16, 2011

19. URIs:
Naming Things
on the Web
Monday, May 16, 2011

20. Naming Things on the Web
• Use http:// URIs
There are other URIs, but http URIs can be used to get more
information quickly and easily
• Use clean, stable URIs
Abstract away implementation details
Ensure they are reliable
• There are two types of resource, both
require URIs
Information Resources — Web pages, images, CSS files etc.
Non-Information Resources — People, places, events, concepts etc.
Monday, May 16, 2011

21. Distinguishing Resources
http://example.com/1969-059A ← Thing
http://example.com/1969-059A.rdf ← RDF data
http://example.com/1969-059A.html ← HTML page
http://example.com/1969-059A ← Thing
http://example.com/1969-059A/rdf ← RDF data
http://example.com/1969-059A/html ← HTML page
http://example.com/resource/1969-059A ← Thing
http://example.com/data/1969-059A ← RDF data
http://example.com/page/1969-059A ← HTML page
Monday, May 16, 2011

22. Use URIs
http://.../topics/physics
URIs provide names for resources
You can say things about resources
"Physics"
Literal values are displayable labels
You can't say more things about "Physics"
Monday, May 16, 2011

23. Use Your Own Domain
http://yours.com/spacecraft/1959-059A
I own the domain, so I can control the meaning of the URI
I can also commit to its permanence and provide data at this
address
http://theirs.com/spacecraft/1959-059A
I don't own this domain, so I can't put any data there
The domain owner may choose to use this URI to mean
something different to me
Monday, May 16, 2011

24. Use Neutral URIs
http://.../spacecraft/1959-059A
The URI contains meaningful, natural or system-neutral keys.
I can route these URIs to any implementation, meaning they
can live forever
Bonus: I'm not advertising my technology choices
http://.../index.aspx?id=3
Nobody wants to know that you're using ASP.Net, really
How will you keep URIs the same when you change or
upgrade your technology?
Monday, May 16, 2011

25. Use http:// URIs
http://.../spacecraft/1969-059A
everyone know what to do with http:// URIs
http:// URIs provide a quick, easy and scalable lookup
mechanism
info:space/1969-059A
http://info-uri.info
info URIs require specialised knowledge
info URIs provide no lookup mechanism
Monday, May 16, 2011

26. Use Natural Keys
http://.../spacecraft/1969-059A
Anyone working with the original data can 'guess' your URIs
You can visually debug, and remember, your own URIs
http://.../809c6e
Nobody can guess this
Monday, May 16, 2011

27. Use Containers (sparingly)
http://.../spacecraft/1969-059A
Containers help keep natural keys separate
Containers provide a natural place to put lists
http://.../1969-059A
What URI do I put a list of all the spacecraft at now?
Monday, May 16, 2011

28. Use Dates (sparingly)
http://.../statistics/2010/agencies
Dates provide a way to show data from a period in time
Most useful for things like statistics, samples or readings
http://.../statistics/agencies
Where am I going to put next year's statistics?
Monday, May 16, 2011

29. Distinguishing Resources
http://example.com/1969-059A.html#self ← Thing
http://example.com/1969-059A.html ← HTML page
Monday, May 16, 2011

30. Fragment Identifiers #
• Useful, with caution
• Fragment identifiers are not sent to the
server
• Limits server-side decision making
• Limits granularity of the response
• Sometimes used with schema when
terms link to human-readable
documentation on the Web.
Monday, May 16, 2011

31. Turtle:
Terse RDF Triple
Language
Monday, May 16, 2011

32. Turtle
• Terse Triple Language (TTL)
http://www.w3.org/2007/02/turtle/primer/
• A human-readable notation for RDF
• Provides useful syntax for quickly
hand-writing RDF
• Forms the basis of patterns in
SPARQL
Monday, May 16, 2011

33. http://... a http://...
/1969-059A /Spacecraft
<http://.../1969-059A> a <http://.../Spacecraft> .
Monday, May 16, 2011

34. Monday, May 16, 2011

35. http://...
/1969-059A
<http://example.com/spacecraft/1969-059A>
Monday, May 16, 2011

36. http://...
/1969-059A
<http://example.com/spacecraft/1969-059A>
a space:Spacecraft ;
a http://...
/Spacecraft
Monday, May 16, 2011

37. http://...
/1969-059A
name
Apollo 11 Command and Service Module
<http://example.com/spacecraft/1969-059A>
a space:Spacecraft ;
space:name "Apollo 11 Command and Service Module" ;
a http://...
/Spacecraft
Monday, May 16, 2011

38. http://...
/1969-059A
name
Apollo 11 Command and Service Module
launched
16 July 1969
<http://example.com/spacecraft/1969-059A>
a space:Spacecraft ;
space:name "Apollo 11 Command and Service Module" ;
space:launched "1969-07-16"^^xsd:date ;
a http://...
/Spacecraft
Monday, May 16, 2011

39. http://...
/1969-059A
name
Apollo 11 Command and Service Module
launched
16 July 1969
<http://example.com/spacecraft/1969-059A>
mass
28801.0 a space:Spacecraft ;
space:name "Apollo 11 Command and Service Module" ;
space:launched "1969-07-16"^^xsd:date ;
space:mass 28801.0 .
a http://...
/Spacecraft
Monday, May 16, 2011

40. http://...
/1969-059A
name
Apollo 11 Command and Service Module
launched @prefix space: <http://example.com/space-schema/> .
16 July 1969
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
<http://example.com/spacecraft/1969-059A>
mass
28801.0 a space:Spacecraft ;
space:name "Apollo 11 Command and Service Module" ;
space:launched "1969-07-16"^^xsd:date ;
space:mass 28801.0 .
a http://...
/Spacecraft
Monday, May 16, 2011

41. Example Turtle
@prefix space: <http://example.com/space-schema/> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
<http://example.com/spacecraft/1969-059A>
a space:Spacecraft ;
space:name "Apollo 11 Command and Service Module" ;
space:launched "1969-07-16"^^xsd:date ;
space:mass 28801.0 .
Monday, May 16, 2011

42. http://...
/1969-059A
name
Apollo 11 Command and Service Module
launched @prefix space: <http://example.com/space-schema/> .
16 July 1969
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
<http://example.com/spacecraft/1969-059A>
mass
28801.0 a space:Spacecraft ;
space:name "Apollo 11 Command and Service Module" ;
space:launched "1969-07-16"^^xsd:date ;
space:mass 28801.0 .
a http://...
/Spacecraft
Monday, May 16, 2011

43. http://... launchsite http://...
/1969-059A /cape+cana...
name name
Apollo 11 Command and Service Module Cape Canaveral, United States
launched @prefix space: <http://example.com/space-schema/> .
16 July 1969
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
<http://example.com/spacecraft/1969-059A>
mass
28801.0 a space:Spacecraft ;
space:name "Apollo 11 Command and Service Module" ;
space:launched "1969-07-16"^^xsd:date ;
space:mass 28801.0 .
a http://...
/Spacecraft
Monday, May 16, 2011

44. http://... launchsite http://...
/1969-059A /cape+cana...
name name
Apollo 11 Command and Service Module Cape Canaveral, United States
launched @prefix space: <http://example.com/space-schema/> .
16 July 1969
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
<http://example.com/spacecraft/1969-059A>
mass
28801.0 a space:Spacecraft ;
space:name "Apollo 11 Command and Service Module" ;
space:launched "1969-07-16"^^xsd:date ;
space:mass 28801.0 .
;
a http://... space:launchsite <http://.../cape+cana...> .
/Spacecraft
Monday, May 16, 2011

45. http://... launchsite http://...
/1969-059A /cape+cana...
name name
Apollo 11 Command and Service Module Cape Canaveral, United States
launched @prefix space: <http://example.com/space-schema/> .
16 July 1969
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
<http://example.com/spacecraft/1969-059A>
mass
28801.0 a space:Spacecraft ;
space:name "Apollo 11 Command and Service Module" ;
space:launched "1969-07-16"^^xsd:date ;
space:mass 28801.0 .
;
a http://... space:launchsite <http://.../cape+cana...> .
/Spacecraft
<http://.../cape+cana...>
space:name "Cape Canaveral, United States"@en-us .
Monday, May 16, 2011

46. Example Turtle
@prefix space: <http://example.com/space-schema/> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
<http://example.com/spacecraft/1969-059A>
a space:Spacecraft ;
space:name "Apollo 11 Command and Service Module" ;
space:launched "1969-07-16"^^xsd:date ;
space:mass 28801.0 ;
space:launchsite <http://.../cape+cana...> .
<http://.../cape+cana...>
space:name "Cape Canaveral, United States"@en-us .
Monday, May 16, 2011

47. RDF/XML
Monday, May 16, 2011

48. Example Turtle
@prefix space: <http://example.com/space-schema/> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
<http://example.com/spacecraft/1969-059A>
a space:Spacecraft ;
space:name "Apollo 11 Command and Service Module" ;
space:launched "1969-07-16"^^xsd:date ;
space:mass 28801.0 ;
space:launchsite <http://.../cape+cana...> .
<http://.../cape+cana...>
space:name "Cape Canaveral, United States"@en-us .
Monday, May 16, 2011

49. http://... a http://...
/1969-059A /Spacecraft
<?xml version="1.0" encoding="utf-8"?>
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<rdf:Description rdf:about="http://.../1969-059A">
<rdf:type rdf:resource="http://.../Spacecraft"/>
</rdf:Description>
</rdf:RDF>
Monday, May 16, 2011

50. http://... launchsite http://...
/1969-059A /cape+cana...
name name
Apollo 11 Command and Service Module Cape Canaveral, United States
launched
16 July 1969
mass
28801.0
a http://...
/Spacecraft
Monday, May 16, 2011

51. Example RDF/XML
<?xml version="1.0"?>
<rdf:RDF
xmlns:space="http://example.com/space-schema/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<rdf:Description rdf:about="http://example.com/spacecraft/1969-059A">
<rdf:type
rdf:resource="http://example.com/space-schema/Spacecraft">
<space:name>
Apollo 11 Command and Service Module
</space:name>
<space:launched rdf:datatype="http://www.w3.org/2001/XMLSchema#date">
1969-07-16
</space:launched>
<space:mass rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">
28801
</space:mass>
<space:launchsite
rdf:resource="http://.../cape+cana..." />
</rdf:Description>
<rdf:Description rdf:about="http://.../cape+cana...">
<space:name xml:lang="en-us">
Cape Canaveral, United States
</space:name>
</rdf:Description>
</rdf:RDF>
Monday, May 16, 2011

52. Example RDF/XML
<?xml version="1.0"?>
<rdf:RDF
xmlns:space="http://example.com/space-schema/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<rdf:Description rdf:about="http://example.com/spacecraft/1969-059A"> subject .
<rdf:type property .
rdf:resource="http://example.com/space-schema/Spacecraft"> value .
<space:name> property .
Apollo 11 Command and Service Module value .
</space:name>
<space:launched rdf:datatype="http://www.w3.org/2001/XMLSchema#date"> property .
1969-07-16 value .
</space:launched>
<space:mass rdf:datatype="http://www.w3.org/2001/XMLSchema#integer"> property .
28801 value .
</space:mass>
<space:launchsite property .
rdf:resource="http://.../cape+cana..." /> value .
</rdf:Description>
<rdf:Description rdf:about="http://.../cape+cana..."> subject .
<space:name xml:lang="en-us"> property .
Cape Canaveral, United States value .
</space:name>
</rdf:Description>
</rdf:RDF>
Monday, May 16, 2011

53. Example RDF/XML
<?xml version="1.0"?>
<rdf:RDF
xmlns:space="http://example.com/space-schema/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<rdf:Description rdf:about="http://example.com/spacecraft/1969-059A">
<rdf:type
rdf:resource="http://example.com/space-schema/Spacecraft">
<space:name>
Apollo 11 Command and Service Module
</space:name>
<space:launched rdf:datatype="http://www.w3.org/2001/XMLSchema#date">
1969-07-16
</space:launched>
<space:mass rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">
28801
</space:mass>
<space:launchsite
rdf:resource="http://.../cape+cana..." />
</rdf:Description>
<rdf:Description rdf:about="http://.../cape+cana...">
<space:name xml:lang="en-us">
Cape Canaveral, United States
</space:name>
</rdf:Description>
</rdf:RDF>
Monday, May 16, 2011

54. Example RDF/XML
<?xml version="1.0"?>
<rdf:RDF
xmlns:space="http://example.com/space-schema/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<space:Spacecraft rdf:about="http://example.com/spacecraft/1969-059A">
<rdf:type
rdf:resource="http://example.com/space-schema/Spacecraft">
<space:name>
Apollo 11 Command and Service Module
</space:name>
<space:launched rdf:datatype="http://www.w3.org/2001/XMLSchema#date">
1969-07-16
</space:launched>
<space:mass rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">
28801
</space:mass>
<space:launchsite
rdf:resource="http://.../cape+cana..." />
</space:Spacecraft>
<rdf:Description rdf:about="http://.../cape+cana...">
<space:name xml:lang="en-us">
Cape Canaveral, United States
</space:name>
</rdf:Description>
</rdf:RDF>
Monday, May 16, 2011

55. Example RDF/XML
<?xml version="1.0"?>
<rdf:RDF
xmlns:space="http://example.com/space-schema/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<space:Spacecraft rdf:about="http://example.com/spacecraft/1969-059A">
<space:name>
Apollo 11 Command and Service Module
</space:name>
<space:launched rdf:datatype="http://www.w3.org/2001/XMLSchema#date">
1969-07-16
</space:launched>
<space:mass rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">
28801
</space:mass>
<space:launchsite>
<rdf:Description rdf:about="http://.../cape+cana...">
<space:name xml:lang="en-us">
Cape Canaveral, United States
</space:name>
</rdf:Description>
</space:launchsite>
</space:Spacecraft>
</rdf:RDF>
Monday, May 16, 2011

56. Other RDF Formats
Monday, May 16, 2011

57. Writing RDF
• Turtle
Easily human readable, to become a W3C Recommendation
(standard)
• RDF/XML
Machine to Machine Transfer, W3C Recommendation (standard)
• N-Triples
One statement per line, subset of Turtle, grep compatible
• RDF/JSON
Useful for AJAX Applications and anything with else JSON support
• RDFa
Writing RDF within HTML pages
Monday, May 16, 2011

58. Example Turtle
@prefix space: <http://example.com/space-schema/> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
<http://example.com/spacecraft/1969-059A>
a space:Spacecraft ;
space:name "Apollo 11 Command and Service Module" ;
space:launched "1969-07-16"^^xsd:date ;
space:mass 28801.0 ;
space:launchsite <http://.../cape+cana...> .
<http://.../cape+cana...>
space:name "Cape Canaveral, United States"@en-us .
Monday, May 16, 2011

59. Example N-Triples
<http://example.com/spacecraft/1969-059A> <http://
www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://
example.com/space-schema/Spacecraft> .
<http://example.com/spacecraft/1969-059A> <http://
example.com/space-schema/name> "Apollo 11 Command and
Service Module" .
<http://example.com/spacecraft/1969-059A> <http://
example.com/space-schema/launched>
"1969-07-16"^^<http://www.w3.org/2001/XMLSchema#date> .
<http://example.com/spacecraft/1969-059A> <http://
example.com/space-schema/mass> "28801"^^<http://
www.w3.org/2001/XMLSchema#integer> .
<http://example.com/spacecraft/1969-059A> <http://
example.com/space-schema/launchsite> <http://.../cape
+cana...> .
<http://.../cape+cana...> <http://example.com/space-
schema/name> "Cape Canaveral, United States"@en-us .
Monday, May 16, 2011

60. Example N-Triples
<http://example.com/spacecraft/1969-059A> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://example.com/space-schema/Spacecraft> .
<http://example.com/spacecraft/1969-059A> <http://example.com/space-schema/name> "Apollo 11 Command and Service Module" .
<http://example.com/spacecraft/1969-059A> <http://example.com/space-schema/launched> "1969-07-16"^^<http://www.w3.org/2001/XMLSchema#date> .
<http://example.com/spacecraft/1969-059A> <http://example.com/space-schema/mass> "28801"^^<http://www.w3.org/2001/XMLSchema#integer> .
<http://example.com/spacecraft/1969-059A> <http://example.com/space-schema/launchsite> <http://.../cape+cana...> .
<http://.../cape+cana...> <http://example.com/space-schema/name> "Cape Canaveral, United States"@en-us .
Monday, May 16, 2011

61. Example RDF/JSON
{
"http://example.com/spacecraft/1969-059A" : {
"http://example.com/space-schema/launched" : [ {
"value" : "1969-07-16",
"datatype" : "http://www.w3.org/2001/XMLSchema#date",
"type" : "literal"
} ],
"http://example.com/space-schema/launchsite" : [ {
"value" : "http://.../cape+cana...",
"type" : "uri"
} ],
"http://example.com/space-schema/mass" : [ {
"value" : "28801",
"datatype" : "http://www.w3.org/2001/XMLSchema#integer",
"type" : "literal"
} ],
"http://example.com/space-schema/name" : [ {
"value" : "Apollo 11 Command and Service Module",
"type" : "literal"
} ],
"http://www.w3.org/1999/02/22-rdf-syntax-ns#type" : [ {
"value" : "http://example.com/space-schema/Spacecraft",
"type" : "uri"
} ]
},
"http://.../cape+cana..." : {
"http://example.com/space-schema/name" : [ {
"value" : "Cape Canaveral, United States",
"lang" : "en-us",
"type" : "literal"
} ]
}
}
Monday, May 16, 2011

62. RDF Schema
Monday, May 16, 2011

63. Who has written a
schema before?
Monday, May 16, 2011

64. Step 1.
Forget what you
think you know
about schema
Monday, May 16, 2011

65. Differences
• In a relational database:
• the schema is external to the data
• the schema comes first
• you must know the schema to query
• In RDF:
• the schema is in the data
• you may query at any time
Monday, May 16, 2011

66. The Open World
• RDF Schema follow the Open World
assumption
• This model assumes that you may not
have all of the information — that more
things may be said elsewhere
• This means that missing isn't
necessarily broken
• RDF Schema are not used for
validation
Monday, May 16, 2011

67. If RDF Schema
aren't for
validation, then
what are they for?
Monday, May 16, 2011

68. RDF Validation
• The Web of Data is about modeling for
re-use
• Reusability is provided by modeling
outside of any one application's
context
• Validation is specific to an application's
context
Monday, May 16, 2011

69. RDF Schema
• RDF Schema are descriptive
• They add additional information to the
graph, through inference
• They add labels to properties and
classes that make dynamic interfaces
possible
• They provide human-readable
descriptions to support schema re-use
• RDF Schema are written as RDF
Monday, May 16, 2011

70. Important
• Properties are first class citizens
they're not hung off classes
• Classes are not OO classes
they do not have any behavior (methods)
or properties...
Monday, May 16, 2011

71. launchsite
http://... http://...
/1969-059A /cape+cana...
name name
Apollo 11 Command and Service Module Cape Canaveral, United States
launched
16 July 1969
mass
28801.0
a http://...
/Spacecraft
Monday, May 16, 2011

72. launchsite
http://... http://...
/1969-059A /cape+cana...
name name
Apollo 11 Command and Service Module Cape Canaveral, United States
launched
16 July 1969
mass
28801.0
a http://...
/Spacecraft
Monday, May 16, 2011

73. Schema Re-use
• RDF & RDFS
rdfs:label — labels for UI use
• Dublin Core
Bibliographic Metadata — title, creator
• FOAF
Friend of a Friend — people, organisations, creations, topics
• SIOC
Online communities — users, accounts, forums, blogs, microblogs
• Geo
Geographical locations — latitude, longitude
• SKOS
Existing taxonomies, thesauri and classification schemes
Monday, May 16, 2011

74. Schema Re-use
Property Schema
name (on Spacecraft)
launched
mass
launchsite
name (on Launchsite)
Monday, May 16, 2011

75. FOAF
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76. Schema Re-use
Property Schema
name (on Spacecraft) foaf:name
launched space:launched
mass space:mass
launchsite space:launchsite
name (on Launchsite) foaf:name
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77. RDF Schema
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
@prefix space: <http://example.com/space-schema/> .
space:launchsite a rdf:Property ;
rdfs:label "Launch Site"@en ;
rdfs:description "The site from which something was launched,
examples would be the launch site of a spacecraft, rocket or
ship"@en ;
rdfs:isDefinedBy space: .
space:mass a rdf:Property ;
rdfs:label "Mass"@en ;
rdfs:description "The mass of an object, measured in Kg" ;
rdfs:isDefinedBy space: .
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78. launchsite
http://... http://...
/1969-059A /cape+cana...
name name
Apollo 11 Command and Service Module Cape Canaveral, United States
launched
16 July 1969
mass
28801.0
a http://...
/Spacecraft
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79. launchsite
http://... http://...
/1969-059A /cape+cana...
name name
Apollo 11 Command and Service Module Cape Canaveral, United States
launched
16 July 1969
mass
28801.0
a http://...
/Spacecraft
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80. RDF Schema
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
@prefix space: <http://example.com/space-schema/> .
space:launchsite a rdf:Property ;
rdfs:label "Launch Site"@en ;
rdfs:description "The site from which something was launched,
examples would be the launch site of a spacecraft, rocket or ship"@en ;
rdfs:isDefinedBy space: .
space:mass a rdf:Property ;
rdfs:label "Mass"@en ;
rdfs:description "The mass of an object, measured in Kg" ;
rdfs:isDefinedBy space: .
space:Spacecraft a rdfs:Class ;
rdfs:label "Spacecraft"@en ;
rdfs:description "A Spacecraft is any man-made object intentionally
launched into space" ;
rdfs:isDefinedBy space: .
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81. Typing with Ranges and Domains
• Properties can add class information to
the subject and value either side of them
• A domain adds type information to the
subject
• A range adds type information to the
value
• Domains and ranges add type
information from the schema to the
instance data
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82. A Launch Site is
any place where
something was
launched
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83. RDF Schema
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
@prefix space: <http://example.com/space-schema/> .
space:launchsite a rdf:Property ;
rdfs:label "Launch Site"@en ;
rdfs:description "The site from which something was launched, examples
would be the launch site of a spacecraft, rocket or ship"@en ;
rdfs:range space:Launchsite ;
rdfs:isDefinedBy space: .
space:mass a rdf:Property ;
rdfs:label "Mass"@en ;
rdfs:description "The mass of an object, measured in Kg" ;
rdfs:isDefinedBy space: .
space:Spacecraft a rdfs:Class ;
rdfs:label "Spacecraft"@en ;
rdfs:description "A Spacecraft is any man-made object intentionally
launched into space" ;
rdfs:isDefinedBy space: .
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84. http://... launchsite http://...
/1969-059A /cape+cana...
name
Cape Canaveral, United States
a http://...
/Spacecraft
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85. http://... launchsite http://...
/1969-059A /cape+cana...
Each
property name
is a
Cape Canaveral, United States
resource
http://...
/launchsite
a http://...
/Spacecraft
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86. http://... launchsite http://...
/1969-059A /cape+cana...
Each
property name
is a
Cape Canaveral, United States
resource
http://... http://...
/launchsite /Launchsite
range
a http://...
/Spacecraft
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87. http://... launchsite http://...
/1969-059A /cape+cana...
Each
property name
is a
Cape Canaveral, United States
resource
http://... a http://...
/launchsite /Launchsite
range
a http://...
/Spacecraft
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88. Property and Class Hierarchies
• Properties and classes can be more
specialised versions of others
• This is done through rdfs:subPropertyOf
and rdfs:subClassOf
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89. LODE
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90. RDF Schema
@prefix lode: <http://linkedevents.org/ontology/> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
@prefix space: <http://example.com/space-schema/> .
space:launchsite a rdf:Property ;
rdfs:label "Launch Site"@en ;
rdfs:description "The site from which something was launched, examples would
be the launch site of a spacecraft, rocket or ship"@en ;
rdfs:range space:Launchsite ;
rdfs:subPropertyOf lode:atPlace ;
rdfs:isDefinedBy space: .
space:mass a rdf:Property ;
rdfs:label "Mass"@en ;
rdfs:description "The mass of an object, measured in Kg" ;
rdfs:isDefinedBy space: .
space:Spacecraft a rdfs:Class ;
rdfs:label "Spacecraft"@en ;
rdfs:description "A Spacecraft is any man-made object intentionally launched
into space" ;
rdfs:isDefinedBy space: .
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91. http://... launchsite http://...
/1969-059A /cape+cana...
name
Cape Canaveral, United States
http://... a http://...
/launchsite /Launchsite
range
a http://...
/Spacecraft
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92. http://... launchsite http://...
/1969-059A /cape+cana...
name
Cape Canaveral, United States
http://... a http://...
/launchsite /Launchsite
range
a http://... subPropertyOf http://...
/Spacecraft /atPlace
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93. atPlace
http://... launchsite http://...
/1969-059A /cape+cana...
Each
property name
is a
Cape Canaveral, United States
resource
http://... a http://...
/launchsite /Launchsite
range
a http://... subPropertyOf http://...
/Spacecraft /atPlace
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94. Naming Convention
• Properties are generally in camel-case
name; launchDate; launchVehicle; crewMember
• RDF Class names are usually in title
case
Person; Spacecraft; Discipline
• Properties use the simplest name they
can
launch; time; destination
• Inverse properties often use 'of'
name & nameOf; crewMember & crewMemberOf
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95. Thanks to
• Rob Styles, Talis Group Ltd for his CC-BY
licensed “Two Day Introduction to the Web of
Data” slides and spacecraft example data.
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96. This work is Copyright © 2010 David Hyland-Wood
Based partially on CC-BY licensed content Copyright © 2010 Talis Systems Limited by Rob Styles.
It is licensed under the Creative Commons Attribution 3.0 Unported License.
Full details at: http://creativecommons.org/licenses/by/3.0/
You are free:
to Share — to copy, distribute and transmit the work
to Remix — to adapt the work
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Attribution. You must attribute the work in the manner specified by the author or licensor (but
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• Some Content in the work may be licensed under different terms, this is noted separately.
Monday, May 16, 2011