July 2002CSM2002, AB + HS1 Ontologies to structure models and modeling tasks Adrie J.M. Beulens and Huub Scholten Wageningen Universiteit, Toegepaste Informatiekunde

July 2002 CSM2002, AB + HS2 The Message n An ontology is a body of structured knowledge, shared by all stakeholders for (re-)use by man and computer n To define knowledge on modeling: Ontology of the modeling process (modeling tasks) n To define knowledge on the problem Ontology of the object system n To develop and exchange models : need for a common model representation format --> develop first: Ontology of (quantitative, algebraic) models

July 2002 CSM2002, AB + HS3 Topics n Introduction n Why ontologies? n What are ontologies? n Why ontologies to solve modeling problems n An overall picture n Discussion

July 2002 CSM2002, AB + HS4 Introduction n 20 years ago: –Ontology: esoteric part of philosophy, about being, about what can be mentioned (Gruninger & Lee, 2002) –Aristotele distinguished in his system theoretical philosophy (physics, ontology, logics) and practical philosophy (ethics, politics, poetics). –The ontology studies ‘what is’ as such, their nature, characteristics and mutual relations n Now (May 2002): –Google finds websites on ‘ontology’ –Term borrowed from knowledge engineering –examples

July 2002 CSM2002, AB + HS5 Example sites on ‘Ontology’ n Gene ontology consortium Gene ontology consortium n What is an ontology? What is an ontology? n Ontology.Org - enabling virtual business Ontology.Org - enabling virtual business n Ontology - descriptive and formal Ontology - descriptive and formal n The ontology page The ontology page n Buffalo ontology site Buffalo ontology site n W3C web ontology (webont) working group W3C web ontology (webont) working group n KR/DB conferences and journal cfps KR/DB conferences and journal cfps n Enterprise project: The enterprise ontology Enterprise project: The enterprise ontology n Kbs/ontology projects worldwide Kbs/ontology projects worldwide

July 2002 CSM2002, AB + HS6 Why ontologies? (1) n A help in structuring complex definitions and arrive at shared understanding n Here: –what elements are needed/allowed in a model definition –what knowledge of an object system is required/essential/relevant to solve a problem using models –what knowledge/expertise on modeling is required for a Good Modeling Practice n Used for: –defining knowledge in general: Internet/WWW –defining protocols in medics and other guidelines –hierarchical knowledge (ecosystems, car repair, ….)

July 2002 CSM2002, AB + HS7 Why ontologies? (2) n Communication: –Between people –Between computers/systems –Between man and computer n Re-use of knowledge n Make assumptions Explicit n Ordering and structuring of knowledge n Analysing of knowledge

July 2002 CSM2002, AB + HS8 What are ontologies? n Two definitions: –Gruber 1994 (for AI systems): A formal specification of a shared conceptualisation (Concept = what “exists” is that which can be represented) –Borst, 1997: An ontology is a formal specification of a shared conceptualisation n Ontologies consists of –Concepts (things you can discuss) –Relations between concepts (consists of, must be preceded by, etc.) –Functions (relations with 1 result) –Instants (specific concept, not generic) –Axiomata (knowledge on concepts/relations that can be checked on its logics)

July 2002 CSM2002, AB + HS9 Representations of ontologies n Languages: –Old: ontolingua, KIF, OKBC, etc. –New (xml-based): XOL, RDF, OIL, DAML+OIL n Tools: –Old: server in Stanford University Knowledge Systems Laboratory –New: Protegé2000 OilEd OntoEdit n Examples ‘formats’: internet

July 2002 CSM2002, AB + HS10 The role of ontologies in MBDS n MB-DS = Model Based Decision Support n Discussed here ontologies on –Problem/object-system ontology –Model ontology –Modeling ontology –How are these related

Example (greenhouse): diagram

Example (greenhouse): ontology in XML/RDF

July 2002 CSM2002, AB + HS13 Problem/object system ontology n Making explicit: –What we are interested in in the OS + reason (problem) –Application domain (which knowledge / science / theories etc.) –Problem owner –Problem: type of application –planning –design –research –operational management description –Existing models

July 2002 CSM2002, AB + HS14 Model ontology n What is a model ontology? –ontology of concepts and mutual relations describing the structure of models (within a modeling paradigm?) n What part of a OS ontology is reflected in a model (paradigm) ontology and how is it reflected? n Examples of model ontologies: –Jan Top (ATO): physical models –to be done (Huub Scholten) ontology on eco-physiological processes of bivalves (+instances) –RWS/RIKZ: generic model for estuarine ecosystems

July 2002 CSM2002, AB + HS15 Modeling ontology n Examples of preliminary steps towards a modeling ontology: –GMP handbook –NEN-norms for modeling water management in the Netherlands n Process oriented: tasks and mutual dependencies –name of task –what?definition –who?modeller, client stakeholder –how?(advice on) methods –which problems to be expected?pitfalls & sensitivities

MB-DS-ontology

July 2002 CSM2002, AB + HS17 Projects related to MB-DS-ontology n Dutch GMP handbook n Norms for model use for Dutch water management n HarmoniQuA n ATO n AMEPS

July 2002 CSM2002, AB + HS18 Discussion n How consistent is the presented approach? –Object system ontology –Model ontology –Modeling ontology n How to deal with domain specific aspects? n Representation formats important?