This document discusses representing Data Documentation Initiative (DDI) metadata using Semantic Web technologies. It describes how DDI elements like variables, concepts, and references can be modeled as RDF triples and integrated with other ontologies. Using Semantic Web techniques allows for linked, distributed querying of DDI data and consistency checking of the DDI model and instances.

1. 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)

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

3. RDF Triples
Age
Subject
references
Predicate
What age?
Object
3

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

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

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

7. 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

8. 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

9. 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

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

11. Concept Hierarchy
Concept subConceptOf
hasConcept
Variable
11

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

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

14. 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

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

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

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