1. Introduction to Ontologies

2. Reusable Specifications as Ontologies An ontology is a partial specification of a conceptual vocabulary to be used for formulating knowledge-level theories about a domain of discourse. The fundamental role of an ontology is to support knowledge sharing and reuse. Example: Ontology Simple-Time Defines classes, relations and axioms to support the modelling of time-dependent activities

3. Classes and Relations in Simple Time Classes Day-Name Day-Number Duration Hour-Number Minute-Number Month-Name Month-Number Second-Number Time-Point Calendar-Date Calendar-Year Universal-Time-Spec Time-Range Year-Number Relations < > After After= Before Before= Disjoint-Time-Ranges During During= Equals Finishes Finishes= Meets Overlaps Overlaps= Start= Starts

4. Definition of Time Point (def-class TIME-POINT (time-position) "A point in time" ((second-of :type second-in-time :max-cardinality 1 ) (minute-of :type minute-in-time :max-cardinality 1 ) (hour-of :type hour-in-time :max-cardinality 1 ) (day-of :type day-in-time :max-cardinality 1) (month-of :type month-in-time :max-cardinality 1) (year-of :type year-in-time :max-cardinality 1 )) :constraint (and (not (and (month-of ?x 2) (> (the ?day (day-of ?x ?day)) 29))) (not (and (member-of ?x (4 6 9 11)) (> (the ?day (day-of ?x ?day)) 30)))))

5. Ontology for medical guidelines What is a medical guideline? – A specification (often partial) of a protocol of care –Aims to define “best practice” –Examples Protocols for treating AIDS patients Protocols for the prevention of bed sores The Ontology –Defines classes, relations and axioms to support the specification of medical guidelines –Builds on a generic medical ontology –Supports both guideline design and execution.

6. Advantages of Ontologies (1): Reuse base-ontology simple-time common-concepts bibliographic-data generic-events medical-ontology medical-guidelines generic-technologies organization-ontology

7. Class Hierarchy for Medical Guidelines Temporal-thing Plan Medical-Guideline Therapeutic-GuidelinePreventive-GuidelineDiagnostic-Guideline Simple-time Ontology Common Concepts Ontology Medical-Guidelines Ontology

8. Advantages of Ontologies (2) Formal Community View –Make it possible to formalise a shared viewpoint over a certain universe of discourse –E.g., agreement on how to model time Interoperability –Can support communication and cooperation between systems developed at different sites –The ontological commitments made by a system are made explicit –E.g., diagnostic and therapy-control medical systems may share the same underlying generic medical ontology e.,g., notion of pathological state, therapeutic procedure

9. Advantages of Ontologies (3) Model-based knowledge acquisition –E.g., use the medical guideline ontology to acquire knowledge about particular medical guidelines in a structured way Knowledge-level validation and verification –E.g., use the medical guideline ontology to check guideline documents

11. (Gruber, 1995) Criteria for Ontology Design Clarity –User-centred definitions –Documentation –Alternative choices Coherence –Logical consistency –Coherent Style (e.g., naming conventions) Minimal ontological commitments –Do not impede extensibility by making unnecessary knowledge-level commitments Minimal encoding bias –Do not pre-judge reuse by making symbol-level commitments

12. Physical Quantity = Example: Example of not-so-good definition (defrelation PHYSICAL-QUANTITY ( (PHYSICAL-QUANTITY ?q) (and (defined (quantity.magnitude ?q)) (double-float (quantity.magnitude ?q)) (defined (quantity.unit ?q)) (member (quantity.unit ?q) (setof meter second kilogram ampere kelvin mole candela)))

13. Physical Quantity = Example: Example of not-so-good definition (defrelation PHYSICAL-QUANTITY ( (PHYSICAL-QUANTITY ?q) (and (defined (quantity.magnitude ?q)) (double-float (quantity.magnitude ?q)) (defined (quantity.unit ?q)) (member (quantity.unit ?q) (setof meter second kilogram ampere kelvin mole candela))) Encoding Bias Unnecessary Ontological Commitment

14. AKT Reference Ontology Task: Develop a common ontology to describe academic resources Rationale: –Ontology to provide a common semantic basis to support variety of AKT services –Gather data about collaborative development –Test tools –Take Integration and Collaboration seriously AKT is a 6-year UK €11M focusing on knowledge technologies, involving 5 universities

15. Organization of AKT Reference Ontology 100% self-contained Two-subontologies –AKT-Support Frames, Sets, Numbers, Lists, Relations, Time, Micro Top Level –AKTive-Portal Technologies, Events, People & Organizations, Documents, Research Areas and Projects

16. Publishing through D3E

17. Setup for collaborative ontology design Screen 1 Ontology Browsers Screen 2 Discussion/Rationale Capture in Compendium

18. Capturing ontology design, discussions, and rationale

19. Publishing through D3E

21. Typology of Comments

22. AKT-2 Architecture Southampton Edinburgh. Aberdeen. Sheffield. OU OKBC Triple Store RDF Wilbur Freaky Aktive Portal Server AKT Reference OntologyAKT Portal KB OCML E-print server Amilcare News server AKT Portal Client AKT Reference Ontology

23. Exercise: Analysis of AKT Reference Ontology

25. Class Medical-Guideline (def-class medical-guideline (plan) "Each guideline is associated with a medical condition. It also targets a particular population" ((outcome-measure :type string) (target-population :type population-specification) (full-name :type string) (associated-medical-condition :type medical-condition) (temporal-constraints :type string) (location-constraints :type guideline-application-location) (associated-documents :type document-reference) (has-guideline-user-type :type guideline-user-type)))