1. Ontology Driven Design of EMF
Metamodels and Well-formedness
Constraints
Benedek Izsó, Zoltán Szatmári, Gábor
Bergmann, Ákos Horváth, István Ráth, and
Dániel Varró
Budapest University of Technology and Economics MODELS Conference – OCL Workshop 2012
Fault Tolerant Systems Research Group Innsbruck, Austria, 2012. 09. 30.

2. Overview
 Motivation
 Ontology based language engineering process
 Ontology to DSL mapping
 Results and future work

3. Motivation
Textual
Requirements ? DSM Editor
«instance of»
• early prototyping
• Every Switch is supervisedBy
• satisfy requirements
at least two Sensors.
• (re)validation

4. Motivation
Formalized Prototype
Requirements Auto-derive DSM Editor
«instance of»
satisfy
Automatically build a
DSM editor to design
instance models
satisfying all requirements

5. Modeling techniques
Requirements Ontology DSL spec.
• Textual • Mathematically • Great tool support
• Can be ambiguous, precise semantics • Wide industry usage
inconsistent • Efficient meta level • Efficient instance
• Expectations of consistency checking model validation
stakeholders • Easy schema merg-
ing and refactoring

6. Modeling techniques
Requirements Consistent translation?
Ontology DSL spec.
• Textual • Mathematically • Great tool support
• Can be ambiguous, precise semantics • Wide industry usage
inconsistent • Efficient meta level • Efficient instance
• Expectations of consistency checking model validation
stakeholders • Easy schema merg-
ing and refactoring

7. Ontology-based modeling techniques
Modeling techniques
Controlled English Tools Automatic transformation
Protégé
Requirements Ontology DSL spec.
• Textual • Mathematically • Great tool support
• Can be ambiguous, precise semantics • Wide industry usage
inconsistent • Efficient meta level • Efficient instance
• Expectations of consistency checking model validation
stakeholders • Easy schema merg-
ing and refactoring

8. Overview of the approach
Mapping
Ontology DSL spec.
OWL2 Ecore
SWRL IQPL

9. Mapping OWL2 to Ecore (example)
Mapping
Ontology DSL spec.
OWL2 Ecore
SWRL IQPL

10. Mapping OWL2 to Ecore (example)
Mapping
Ontology DSL spec.
Every Switch is a TrackElement.
Every TrackElement is supervisedBy a Sensor.
OWL2 Ecore
SWRL IQPL

11. Mapping OWL2 to Ecore (example)
Mapping
Ontology DSL spec.
Every Switch is a TrackElement.
Every TrackElement is supervisedBy a Sensor.
Switch ⊑ TrackElement
Switch ⊑
OWL2 (Web Ontology Language):
∃ supervisedBy.Sensor
• W3C Standard for describing
semantic web
• Axiomatic language: decidable
description logic
• Here used for metamodel
constraint description
OWL2 Ecore
SWRL IQPL

12. Mapping OWL2 to Ecore (example)
Mapping
Ontology DSL spec.
Every Switch is a TrackElement.
Every TrackElement is supervisedBy a Sensor.
Switch ⊑ TrackElement
Switch ⊑
∃ supervisedBy.Sensor
OWL2 Ecore
SWRL IQPL

13. Mapping OWL2 to IQPL (example)
Mapping
Ontology DSL spec.
OWL2 Ecore
SWRL IQPL

14. Mapping OWL2 to IQPL (example)
Mapping
Ontology DSL spec.
Every Switch is supervisedBy at least two Sensors.
OWL2 Ecore
SWRL IQPL

15. Mapping OWL2 to IQPL (example)
Mapping
Ontology DSL spec.
Every Switch is supervisedBy at least two Sensors.
Switch ⊑
≥2 supervisedBy.Sensor
OWL2 Ecore
SWRL IQPL

16. Mapping OWL2 to IQPL (example)
Mapping
Ontology DSL spec.
Every Switch is supervisedBy at least two Sensors.
IQPL (IncQuery Pattern Language):
• Graph pattern based model query
language
• EMF-IncQuery evaluates incrementally
Switch ⊑
NEG
supervisedBy
≥2 supervisedBy.Sensor s1:Sensor
OWL2 Ecore s2:Sensor supervisedBy
sw:Switch
SWRL IQPL

17. Mapping OWL2 to IQPL (example)
Mapping
Ontology DSL spec.
Every Switch is supervisedBy at least two Sensors.
Consequent is negated
to match violating
elements
Switch ⊑
NEG
supervisedBy
≥2 supervisedBy.Sensor s1:Sensor
OWL2 Ecore s2:Sensor supervisedBy
sw:Switch
SWRL IQPL

18. Mapping SWRL to IQPL (example)
Mapping
Ontology DSL spec.
OWL2 Ecore
SWRL IQPL

19. Mapping SWRL to IQPL (example)
Mapping
Ontology DSL spec.
Two track elements with same signal must be connected.
OWL2 Ecore
SWRL IQPL

20. Mapping SWRL to IQPL (example)
Mapping
Ontology DSL spec.
Two track elements with same signal must be connected.
TrackElement(?te1),
TrackElement(?te2),
Signal(?sig),
hasSignal(?te1, ?sig),
hasSignal(?te2, ?sig), SWRL (Semantic Web Rule Language):
DifferentFrom (?te1, ?te2) • Extension of OWL2
->
connectedTo(?te1, ?te2) • Variables and property expressions
can be used
OWL2 Ecore • DL-Safe rules maintain decidability
SWRL IQPL

21. Mapping SWRL to IQPL (example)
Mapping
Ontology DSL spec.
Two track elements with same signal must be connected.
TrackElement(?te1),
TrackElement(?te2),
Signal(?sig),
hasSignal(?te1, ?sig),
hasSignal(?te2, ?sig),
DifferentFrom (?te1, ?te2) ?te1:TrackElement
hasSignal
-> NEG
connectedTo(?te1, ?te2) ?sig:Signal connectedTo
hasSignal
OWL2 Ecore ?te2:TrackElement
SWRL IQPL

22. Mapping SWRL to IQPL (example)
Mapping
Ontology DSL spec.
Two track elements with same signal must be connected.
pattern invalidWiring(te1, te2, sig) {
TrackElement(?te1), TrackElement(te1);
TrackElement(?te2), TrackElement(te2);
Signal(?sig), Signal(sig);
hasSignal(?te1, ?sig), TrackElement.hasSignal(te1, sig);
hasSignal(?te2, ?sig), TrackElement.hasSignal(te2, sig);
DifferentFrom (?te1, ?te2) te1 != te2;
-> neg find connected(te1, te2);
connectedTo(?te1, ?te2) }
pattern connected(te1, te2) {
OWL2 Ecore TrackElement.connectedTo(te1, te2);
}
SWRL IQPL

23. Language Differences
OWL2+SWRL Ecore + IQPL Solution
Multityped instances Object has exactly one Multiple inheritance
direct type can be used
Relation inheritance No relation Mapped to GP,
allowed inheritance relation instances
must be inserted
Multiple syntax can Transformed to Ecore
have one semantics or GP depending on
the syntax
Open world Closed world OWA → tolerates
assumption assumption incomplete models
CWA → complete
knowledge assumed

24. Language Differences (OWA → CWA)
Ontology DSL spec.
Every Switch is supervisedBy at least two Sensors.
s2:Sensor supervisedBy
sw:Switch

25. Language Differences (OWA → CWA)
Ontology DSL spec.
Every Switch is supervisedBy at least two Sensors.
Open World Assumption:
Tolerates incomplete knowledge
✓ Valid
s2:Sensor supervisedBy
sw:Switch

26. Language Differences (OWA → CWA)
Ontology DSL spec.
Every Switch is supervisedBy at least two Sensors.
Open World Assumption: Closed World Assumption:
Tolerates incomplete knowledge Complete knowledge assumed
✓ Valid ✘Invalid
s2:Sensor supervisedBy
sw:Switch

27. Language Differences (OWA → CWA)
Ontology DSL spec.
Every Switch is supervisedBy at least two Sensors.
Open World Assumption: Closed World Assumption:
Tolerates incomplete knowledge Complete knowledge assumed
✓ Valid ✘Invalid
s2:Sensor supervisedBy
sw:Switch
Mapped graph patterns return invalid elements
following the close world assumption

28. Implementation
Transform
Ontology DSL spec.
 Large part of the language was mapped (~50 axioms
and 45 expressions)
 Transformation is implemented in the VIATRA2
framework with the required ontology importer,
Ecore and IQPL exporter
 Traceability between source and target model
 An Eclipse plug-in automates the process
o Converts ontology with 50 axiom in 30 sec. (code
generation dominates)

29. Results
Consistent Automatic transformation
formalization
Requirements Ontology DSM Editor
(textual) (formal) (prototype)
«instance of»
Efficiently check
consistent requirements of
large, continuously
evolving models

30. Results
Consistent Automatic transformation
formalization
Requirements Ontology DSM Editor
(textual) (formal) (prototype)
«instance of»
Efficiently check
consistent requirements of
large, continuously
evolving models

31. Future work
Requirements Ontology DSL spec.
(textual) (OWL2+SWRL) (Ecore+IQPL)
«instance of»

32. Future work
Requirements Ontology DSL spec.
(textual) (OWL2+SWRL) (Ecore+IQPL)
«instance of» «instance of»
Ontology
instance
Instance model
mapping

33. Future work
Reverse mapping
(expressivity!)
Requirements Ontology DSL spec.
(textual) (OWL2+SWRL) (Ecore+IQPL)
«instance of» «instance of»
Ontology
instance
Instance model
mapping

34. Future work
Reverse mapping
(expressivity!)
Requirements Ontology DSL spec.
(textual) (OWL2+SWRL) (Ecore+IQPL) OCL
«instance of» «instance of»
Ontology
instance
Instance model
mapping

35. Summary
Consistent Automatic transformation
formalization Mapping
Requirements Ontology DSM Editor
«instance of»
Efficiently check
large models on-the-fly