1. Knowledge Representation Part V RDF
The representational power of three.
Jan Pettersen Nytun, UiA

2. RDF - The Resource Description Framework A Framework For Describing Resources
“Resources can be anything, including documents, people, physical objects, and abstract concepts.” [3]

3. The Semantic Web Language Stack
Hierarchy of languages, where each layer exploits and uses capabilities of the layers below.
/ XML Schema

4. Agenda Semantic Networks and Triples RDF and Triples
Representing RDF with XML
Representing RDF with Turtle
Protégé - Turtle Example
W3C Technology

5. Associationist
… meaning of an object is given in terms of a network of associations with objects…perception mapped into a concept which is connected through relationships to other concepts.
Graphs (arcs and nodes) are ideal vehicle for formalizing associationist theories of knowledge. Example: Semantic networks.
Background of OWL

6. Semantic Networks Represents knowledge in the form of a graph where:
the nodes correspond to facts or concepts
the arcs correspond to relations or associations between the concepts
BreastCanser
hasSickness
Christine
hasDiagnosis
DiagnosisId_1
High
hasDiagnosisProbability

7. The use of triples for representation.
Example: <Christine, hasDiagnosis, DiagnosisId_1>
< DiagnosisId_1, hasSickness, BreastCanser>
< DiagnosisId_1, hasDiagnosisProbability, High>
BreastCanser
hasSickness
Christine
hasDiagnosis
diagnosis_id_1
High
hasDiagnosisProbability

8. <subject> <predicate> <object> A triple is saying something (object/value), about something (subject), in regard to something (predicate/property).

9. Graphical Representation of Triples
In general:
predicate
subject
object
Example: <NursingReport_1, hasPatient, Kenny>
hasPatient
NursingReport_1
Kenny

10. Agenda RDF and Triples Semantic Networks and Triples
Representing RDF with XML
Representing RDF with Turtle
Protégé - Turtle Example
W3C Technology

11. The Conceptual model of RDF
Triples
Semantic networks

12. The following UML class model has been instantiated when the object diagram was made:
teachIn *
follows *
Student
Course
Teacher *
participant *
taughtBy
-studentId
-name
-courseId
-teacherId
-name
Task: How to represent the following object diagram as triples graphically (and textually).
s1:Student
c1:Course
t1:Teacher
studentId = 101
name = Ola
courseId = IKT413
teacherId = 1
name = Kari
s2:Student
studentId = 102
name = Olga

13. t1 rdf:type s1 rdf:type Student . s1 studentId 101 . s1 name “Ola” .
c1:Course
t1:Teacher
studentId = 101
name = Ola
courseId = IKT413
teacherId = 1
name = Kari
rdf:type
s1 rdf:type Student .
s1 studentId
s1 name “Ola” .
s1 follows c1 . ….
s2:Student t1
studentId = 102
name = Olga
teacherId = 1
Name = “Kari” s1
participant
taughtBy
rdf:type
follows
studentId = 101
Name = “Ola” c1
Student
follows
studentId = 101
Name = “Ola” s2
rdf:type
rdf:type
studentId = 102
Name = “Olga”
participant
Teacher

14. RDF Triple[7] An RDF triple contains:
the subject - an RDF URI reference or a blank node
the predicate - an RDF URI reference
the object - an RDF URI reference, a literal (string, number, etc.) or a blank node
blank node = anonymous node

15. Agenda Representing RDF with XML Semantic Networks and Triples
RDF and Triples
Representing RDF with XML
Representing RDF with Turtle
Protégé - Turtle Example
W3C Technology

16. XML - Used as Representational Language[6]
<?xml version="1.0"?> <rdf:RDF xmlns:rdf=" xmlns:si =" <rdf:Description rdf:about="   <si:title>W3Schools.com</si:title>   <si:author>Jan Egil Refsnes</si:author> </rdf:Description> </rdf:RDF>
Knowledge Representation Part I, JPN, UiA

17. [8]: "there is a Person identified by http://www. w3
[8]: "there is a Person identified by whose name is Eric Miller, whose address is and whose title is Dr."
<?xml version="1.0"?>
<rdf:RDF xmlns:rdf="
xmlns:contact="
<contact:Person rdf:about="
<contact:fullName>Eric Miller</contact:fullName>
<contact:mailbox
<contact:personalTitle>Dr.</contact:personalTitle>
</contact:Person>
</rdf:RDF>

18. Blank Node (Anonymous Resource) From Wikipedia
In RDF, a blank node (also called bnode) is a node in an RDF graph representing a resource for which a URI or literal is not given.
<foaf:Person rdf:about="
<foaf:knows>
<foaf:Person rdf:nodeID="b1"/>
</foaf:knows>
</foaf:Person>
<foaf:Person rdf:about="

19. Agenda Representing RDF with Turtle Semantic Networks and Triples
RDF and Triples
Representing RDF with XML
Representing RDF with Turtle
Protégé - Turtle Example
W3C Technology

20. Terse Language for Triples Turtle
RDF/XML is the originally unique syntax and standard for writing RDF. Turtle is an alternative. Turtle does not rely on XML and is more readable and easier to edit manually than its XML counterpart.

21. A triple is written simply as: Subject Predicate Object .
A URI is often written within angle brackets, e.g., 〈
The URI 〈〉 refers to the current document, e.g., 〈#comp_2347〉 denotes an individual defined in the current document.

22. Example
〈#comp_2347〉 〈#owned_by〉 〈#craig〉 〈#comp_2347〉 〈#model〉 〈#lemon_laptop_10000〉 . 〈#comp_2347〉 〈#brand〉 〈#lemon_computer〉 〈#comp_2347〉 〈#logo〉 〈#lemon_disc〉 〈#comp_2347〉 〈#color〉 〈#brown〉 〈#craig〉 〈#room〉 〈#r107〉 …

23. Turtle Abbreviations
A semicolon is used to group predicate-object pairs for the same subject. S P1 O1; P2 O2. is an abbreviation for S P1 O1. S P2 O2. E.g.: 〈#comp_3645〉 〈#owned_by〉 〈#fran〉 ; 〈#color〉 〈#green〉. equals: 〈#comp_3645〉 〈#owned_by〉 〈#fran〉. 〈#comp_3645〉 〈#color〉 〈#green〉.

24. Turtle Abbreviations Continues…
A comma can group objects with the same subject and predicate. S P O1, O2 . is an abbreviation for S P O1 . S P O2 . E.g.: 〈#comp_3645〉 〈#color〉 〈#green〉, 〈#yellow〉 . equals: 〈#comp_3645〉 〈#color〉 〈#green〉 . 〈#comp_3645〉 〈#color〉 〈#yellow〉.

25. Turtle Abbreviations Continues…
Square brackets can be used to define an individual that is not given an identifier, i.e., a blank node. [P1 O1; P2 O2] is an individual that has value O1 on property P1 and has value O2 on property P2.

26. Anonymous individual (blank node) - example:
〈comp_3645〉 〈#managed_by〉 [〈#occupation〉 〈#sys_admin〉]. Equals: 〈comp_3645〉 〈#managed_by〉 〈i2134〉. 〈i2134〉 〈#occupation〉 〈#sys_admin〉. the made-up URI, 〈i2134〉, cannot be referred to outside the document. As we can see, the anonymous individual can be used as the object of a triple.

27. Complex Example 〈comp_3645〉 〈#owned_by〉 〈#fran〉.
〈comp_3645〉 〈#color〉 〈#green〉,〈#yellow〉.
〈comp_3645〉 〈#managed_by〉 [
〈#occupation〉 〈#sys_admin〉;
〈#serves_building〉 〈#comp_sci〉] .
〈comp_3645〉
〈#owned_by〉 〈#fran〉;
〈#color〉 〈#green〉,〈#yellow〉;
〈#managed_by〉 [
〈#occupation〉 〈#sys_admin〉;
〈#serves_building〉 〈#comp_sci〉] .
〈comp_3645〉 〈#owned_by〉 〈#fran〉.
〈comp_3645〉 〈#color〉 〈#green〉.
〈comp_3645〉 〈#color〉 〈#yellow〉.
〈comp_3645〉 〈#managed_by〉 <i2134>.
<i2134> 〈#occupation〉 〈#sys_admin〉;
〈#serves_building〉 〈#comp_sci〉] .
〈comp_3645〉 〈#owned_by〉 〈#fran〉.
〈comp_3645〉 〈#color〉 〈#green〉.
〈comp_3645〉 〈#color〉 〈#yellow〉.
〈comp_3645〉 〈#managed_by〉 [
〈#occupation〉 〈#sys_admin〉;
〈#serves_building〉 〈#comp_sci〉] .
〈comp_3645〉 〈#owned_by〉 〈#fran〉.
〈comp_3645〉 〈#color〉 〈#green〉.
〈comp_3645〉 〈#color〉 〈#yellow〉.
〈comp_3645〉 〈#managed_by〉 〈 i2134 〉.
〈 i2134 〉 〈#occupation〉 〈#sys_admin〉.
〈 i2134 〉 〈#serves_building〉 〈#comp_sci〉].

28. Agenda Protégé - Turtle Example Semantic Networks and Triples
RDF and Triples
Representing RDF with XML
Representing RDF with Turtle
Protégé - Turtle Example
W3C Technology

29. Example: Some RDF Standard Properties + Turtle Representation

33. Some RDF Standard Properties - Turtle Representation Continues…
@prefix : < .
@prefix owl: < .
@prefix rdf: < .
@prefix xml: < .
@prefix xsd: < .
@prefix rdfs: < .
@base < .
< rdf:type owl:Ontology .

34. Some RDF Standard Properties - Turtle Representation Continues…
###
:hasName rdf:type owl:DatatypeProperty ;
rdfs:range xsd:string .
###
:hasPatient rdf:type owl:ObjectProperty .
:EHealthRecord rdf:type owl:Class .
:Patient rdf:type owl:Class .

35. Some RDF Standard Properties - Turtle Representation Continues…
:ID_JPN rdf:type :Patient ,
owl:NamedIndividual ;
rdfs:label "Jan Pettersen Nytun" ;
:hasName "Jan Pettersen Nytun"^^xsd:string .
:eHealtRecord_Jan rdf:type :EHealthRecord ,
rdfs:label "Health Record for Jan Pettersen Nytun" ;
:hasPatient :ID_JPN .

36. References
[1] Book: David Poole and Alan Mackworth, Artificial Intelligence: Foundations of Computational Agents, Cambridge University Press, 2010, [2] [3] RDF 1.1 Primer, W3C Working Group Note, 24 June 2014