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Simplifying OWL

BioHealth Informatics Group. Simplifying OWL. Learning lessons from Anaesthesia Nick Drummond. Overview. IOTA Requirements Challenges Separating language from identity Referencing non-OWL resources Hiding complexity Optionality in OWL Conclusion. Guinea Pig - IOTA.

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Simplifying OWL

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  1. BioHealthInformaticsGroup Simplifying OWL Learning lessons from Anaesthesia Nick Drummond

  2. Overview • IOTA • Requirements • Challenges • Separating language from identity • Referencing non-OWL resources • Hiding complexity • Optionality in OWL • Conclusion

  3. Guinea Pig - IOTA • International Organisation for Terminology in Anaesthesia • Part of the Anaesthesia Patient Safety Foundation • 2 parallel efforts: • official feed of anaesthesia terms to SNOMED-CT • Ontology required for AIMS systems

  4. IOTA Tools • Had DATAMS browser/editor • Simple interface • Completely designed for single task • But • Non standard solution – no semantics defined • Limited functionality • Restricted support • Not extensible • Only 2 relationships (isa, hasa)

  5. Requirements • Simple browsing/editing environment • Standards for reuse • Heavily concerned with language and references to external resources (for SNOMED) • Simple structure but above and beyond sub/superclass (more properties wanted)

  6. OWL Subset • Subsumption • Primitive classes only (so far) • Existential / Complement / Cardi restrictions (identified through competency questions) • No complex fillers – only Named Classes • No disjoints (yet) – likely to be added automatically • Lots of annotations

  7. Challenges • Separating language from identity • Referencing non-OWL resources • Hiding complexity • Optionality in OWL

  8. Separating language from identity vin wine • Resources are referred to by their URI • rdfs:label or other properties can be used to hold the human-readable name • IDs remain constant when renaming • Can have multiple names (in different languages) • Label string values less restricted (can use spaces etc) • Can use the same label for multiple resources (disadvantage??) plonk

  9. Separating ID from language in Protege • Meaningless IDs generated automatically • conceptName is human readable • Protégé supports idea of “Browser Slot” • ie the property that is displayed to the user • Extra search support needed

  10. Referencing non-OWL resources • owl:seeAlso • Have no URI to point to in SNOMED • Create an individual in which to store any SNOMED info (such as name etc) • Can be refactored later to point to the actual concept (if SNOMED ever published in OWL)

  11. Hiding Complexity • Backward Es and upside-down As best left to the logicians • Not all expressivity of OWL required • eg “simple” fillers – just named classes • Currently no defined classes

  12. Disguising OWL • Protégé forms are customisable • forms design for purpose • plugin form widgets • Use min/max qualified cardinality • Display “compound” restrictions

  13. Using qualified cardinality and compound restrictions

  14. Optionality • Common requirement • 2 use cases: • Reasoning – using ontological knowledge – an object may or may not have this feature • Driving Forms – using epistemic knowledge – an object has this feature. The value may or not need to be specified

  15. Representing optionality in OWL • No inbuilt notion in OWL • Because of the open world assumption, possible to say anything about anything unless it has been explicitly discounted • Several “patterns”, “workarounds” or “botches” – could be subject in themselves • We are considering a mixture to help make INTENT obvious and simple to manage but allow for CORRECT modelling in OWL

  16. Options (overview) • State nothing (Open World) • Using domain of property • Use of “possibly…” superproperty • Universal/Existential restrs on inverse • Reification • Tool specific annotations • Qualified Min Cardinality 0 • Define a subclass that has the property

  17. Defined Subclass Person (some people own hats) • Ontologically correct • Can infer membership / check consistency PersonThatOwnsAHat { complete Person and owns some Hat } • Hard to maintain • Loses intent – conceptually we are saying something about members of Person

  18. Min Cardi 0 (Qualified) • QCRs standard in OWL1.1 • Means nothing to reasoners, but… • Captures intent • matches our conceptual model and close to other representations – relational models • Simple to add/manage in OWL • Easy to use as hints for GUI generation

  19. Transform • Allow user to maintain intent – ie min cardi • Provide transform to create subclasses only WHEN REQUIRED • Throw away when finished ? ? www

  20. Conclusion • IOTA have some common problems • Many can be overcome – even in OWL  • Open environments like Protégé can help create simpler interfaces • General requirements found for Protégé-OWL

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