Representation without Reason:

Slow Progress toward the Semantic Web

Jim GreerARIES Laboratory

Computer Science, University of Saskatchewan

The Attraction of Ontologies

Shared meanings Nice formal representationSound reasoning facilityOnce built, they remain stableBuilding an ontology brings deep

understanding and requires reflection

Concept Maps and Taxonomies

Historically useful in educationLearning is strengthened by

constructing concept mapsSocial construction of knowledgeA small leap from taxonomy to

ontology?

Formal models and meaning

Semantics through links, rules, and propagation

RDF triples for micro-content Foundation of our MUMS systemAggregation and abstraction

Our early work on granularity

Indexing content

Ontologies are convenient to useSimple representationTrivial inference needed

Propagation through link semantics

Natural to attach metadataBut can we all agree? Must we?Do we need more than taxonomies?

Our Ontology work

Debate over “the” representationDomain concepts are fluidFall back to concept mappingSemantics weakenTop-down reasoning vanishesResort to folksonomies/data-

mining

Tempting E-Learning Illusions

Concept maps => OntologiesTeachers / learners can understand

ontologiesTeachers, learners and machines have a

common understanding of an ontologyUsers will embrace ontologiesEasy to build an ITS once the ontology is

right

“My own” ontology

Formal modelling tool based on consensus

Gaining popularity in MDA (formal specification)

Shared meanings in a small closed community

My ontology is better than yours!

Ontology mapping

Translate one ontology to anotherAppealing notion if no agreement

can be reachedTougher than it looks…

All-too-common use case

Ontology is built by a group with much effort

Every user wants to tweak the ontology

Ontology becomes primarily a representation tool (taxonomy)

No sophisticated reasoning happens

Is there enough benefit?

Why is the semantic web proceeding so slowly?

Where did the agents go?Are ontologies really promoting

interoperability?How much prototyping and informal

modelling is needed prior to building an ontology?

What does the ontology really do for learners?

Jim’s SWEL Challenge

Tools for the emergent ontologyLearning an ontology from associations

Substantial reasoning with ontology Use cases where reasoning is key

Make ontologies truly usefulToo many people “can’t be bothered”Formal structures must pay off.