Presentation on theme: "The Immediate Prospects for the Application of Ontologies in Digital Libraries Jody DeRidder Spring 2007 IS 565, Digital Libraries Dr. Suzie Allard, Professor."— Presentation transcript:
The Immediate Prospects for the Application of Ontologies in Digital Libraries Jody DeRidder Spring 2007 IS 565, Digital Libraries Dr. Suzie Allard, Professor
What are Ontologies? Thesaurus: …. And MORE!! Parent Child Instance: Andy is a child. Sarah is a child. NT Father NT Daughter Relation: “fight” NT Mother NT Son Axiom: Sarah and Andy always fight. RT Child RT Parent Constraint: Until their parents stop them! An ontology is like an expanded thesaurus. Methods of encoding our concepts and their relationships so computers can understand us, and help us find what we need.
Ontology components (constructs) concepts (and their properties) instances (examples of concepts) relations axioms (always true) constraints (only true if) Wine Beringer White Zinfandel Grapes Zinfandel Grapes Type of Made From BUT!! Only when produced by Beringer Corp. White Zinfandel Type of Produces Always Made From Type of Made From
Lightweight Ontologies: are little more than taxonomies, and include: concepts, properties that describe concepts, and relationships. An example of this would be Dublin Core Heavyweight ontologies: also include axioms and logic constraints An example of this would be Cyc Ontology Types: Depth of Territory The more heavyweight the ontology is, the more expressive and powerful – and the more complex and costly to create, implement, and maintain.
Global Ontologies Domain Ontologies Application Ontologies Ontology Types: Breadth of Territory Simpler for computer applications if we can all map to a single global ontology – but MUCH more difficult for humans to agree on, implement, and maintain. BotanyArtHistory Creating Lesson Plans Identifying Diseases By Symptomology
An Audio Tape Ontology Example
An example use of an ontology in education… Alexandria Digital Earth Prototype
-- where you can select a food and the software will choose appropriate wines to accompany your meal. An example you can play with: Wine Agent 1.0 How does it work? If seafood is tagged as having the property of requiring a dry white wine; and swordfish is listed as an instance (type) of seafood; and a certain Swiss Chardonnay has been added as an instance (type) of dry white wine– then when you ask what wine to serve with swordfish, this Chardonnay would be suggested to accompany your dinner.
Ontology Mapping So… we all speak different “languages” or ontologies; to support searching across the variation of terms, we need to map each ontology onto the others… a form of translation. One such ontology mapping language is XeOml, which allows one-to-one or one-to-many mappings between elements of two ontologies. From: Harebell Downiniga elegans showy downinig a Purple flower
Problems in Ontology Mapping Michael Klein,
How do query engines use ontology mapping? An example from OBSERVER [Mena, 2000]
Standards, the bottom line for interoperability To represent knowledge so that computers can “understand” us, we need to use formats they can process, and a language they can understand. For applications to be interoperable, we need agreed-upon standards: Resource Description Framework (RDF) is a simple notation for representing relationships between and among concepts. Each concept is represented by a URL. Web Ontology Language (OWL) is a more complex artificial language for the exact description of things and their relationships.
RDFRDF: Resource Description Framework Eric Miller
OWLOWL: Web Ontology Language OWL and RDF have similarities, but OWL is a much stronger language with greater machine interpretability than RDF. Three Sublanguages: * OWL Lite Hierarchical Classification, simple constraints. Three Sublanguages * OWL DL Description Logic: as expressive as is possible while maintaining the logic needed for computers to reason and make inferences. * OWL Full Maximum expressiveness with no computational guarantees. Think of this OWL and RDF as frameworks for concepts and their possible relations. You use the framework to encode the Ontology.
Ontologies… who needs them? Findability Query Expansion Reasoning …to help us sift through the exponential growth of digital materials We do!!!
Ontology Implementation Tasks Simperl and Tempich, 2006
What are the costs? Product factors complexity of the domain analysis, conceptualization, implementation, instantiation, evaluation, integration, reusability, and documentation Personnel factors ontologist/domain expert capability & experience, language and tool experience, and personnel continuity Project factors tool support, multi-site development, required development schedule Reuse/maintenance factors ontology understandability, domain/expert unfamiliarity, complexity of evaluation, modifications, and translations ONTOCOM: How complex is your ontology? Heavyweight or lightweight? And how broad is your domain?
Where are ontologies most feasible? Commercial Ventures and Commercially Funded Research Example: Xyleme Government (especially Defense) Example: Ontology Works Possibly Education ? If you work in one of these areas, * you * will likely be using ontologies!
For the rest of us… If you are in a general purpose digital library, and you have the funding: start the research (what is your target audience’s terminology, versus the terminology of your content descriptions?) watch the tools develop, and test them watch for domain and global ontologies that are given the W3C stamp of approval!... IT WON’T BE LONG NOW! Until the development, application, and maintenance becomes cheaper and easier, ontologies will not be feasible for general purpose digital libraries without major ongoing funding.
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