Representation of the
Data Documentation Initiative using
Semantic Web Technologies
IASSIST 2011
02.06.2011
Thomas Bosch
(research associate, GESIS Leibniz Institute for the Social Sciences)

Agenda
• What is the Semantic Web (SW)?
• Why should the SW be applied in the context of DDI?
• Take-aways and Discussion
2

RDF Triples
Age
Subject
references
Predicate
What age?
Object
3

Ontologies
class property class
domain range
Variable references Question
type type type
Age What age?
references
resource resource resource
4

Agenda
• What is the Semantic Web (SW)?
• Why should the SW be applied in the context of DDI?
• Take-aways and Discussion
5

Publish and Link DDI Data and Metadata
Linking Open Data cloud diagram, by Richard Cyganiak and Anja Jentzsch. http://lod-cloud.net/ 6

Semantic Queries
• What kinds of problems can be solved?
• Queries on multiple, distributed and merged DDI instances
• Formulation using DDI domain concepts
?question
contains
questionScheme ?question
SELECT ?question ?question
WHERE { questionScheme contains ?question. } 7

Integration of Other Ontologies
• Ontology domain classes can relate to
similar concepts of external ontologies
• Reasoner may use additional
semantic information
DDI Other
Ontology Ontologies
(Question) (Question)
8

DDI Consistency Check
• Definition of 'consistency'
• OWL reasoning techniques
• Class consistency
• Global consistency
• Global consistency of DDI ontology
Global consistency of DDI data model
9

Concept Hierarchy
Variable Concept Concept
Concept
SimilarConcept
Reference
SimilarConcept
Difference
Reference
text + html
(superClassOf)
10

Concept Hierarchy
Concept subConceptOf
hasConcept
Variable
11

DDI Elements‘ Comparability
Grade_USA
hasCode
subClassOf
A subClassOf
Variable Code
subClassOf
1.0
subClassOf
hasCode
Grade_Germany
• Necessary conditions (equality, inequality, similarity, …)
12

References
OtherMaterial type
ExternalURL
Citation Relationship
Reference
RelatedTo
DCElements ...
Reference
Title Creator URN
… … ...
13

References
OtherMaterial type
Drawbacks:
ExternalURL
Citation Relationship
Reference
• Complex data model
• No intuitive semantics
RelatedTo
DCElements ... • Bibliographic citation
Reference
limits
• Ensure reusability?
Title Creator URN
… … ...
14

Semantic References
referencesPublication
Referencing
Publication ID
Publication
subClassOf
X
publicationReferencedBy
Variable Title Creator Date URL
15

Agenda
• What is the Semantic Web (SW)?
• Why should the SW be applied in the context of DDI?
• Take-aways and Discussion
16

http://ddiandsemanticweb.blogspot.com
Subject
Predicate Assertional
RDFTriple
Ontology
Terminological
Object