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Tools for Developing and Using DAML-Based Ontologies and Documents Richard Fikes Deborah McGuinness Sheila McIlraith
Jessica Jenkins Son Cao Tran Gleb Frank Scott Sanner Honglei Zeng
Knowledge Systems Laboratory, Computer Science Department, Stanford University The Chimaera Ontology Tool Suite A Knowledge Evolution Environment
Tools for ontology diagnosis and merging
Available as a Web service
Usable from a Web browser
Online user manual, tutorial, and demonstration movie
www.ksl.stanford.edu/software/chimaera
Performs ontology diagnostics in batch mode
Uploads and analyzes user’s ontology
Accepts KBs in DAML+OIL, DAML ONT, RDF, XML, KIF, OKBC, …
Provides results as HTML pages linked to frames and axioms
Provides user selectable set of diagnostic tests
Analyzes both the structure and content of an ontology
Uses reasoners to analyze content
Currently runs 28 diagnostic tests
Is an OKBC client that runs with any OKBC server
OKBC – Open Knowledge Base Connectivity
We use our Ontolingua OKBC knowledge server
Ontology editor supports –
>
Editing object-oriented descriptions (frames)
>
Inclusion of ontologies from any Web sites
Ontology browser shows –
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Frames with inherited values and constraints
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Ontology inclusion structure
>
Class-subclass taxonomy
Uses our JTP theorem prover to perform reasoning tests
Enables heterogeneous reasoners to interoperate
Contains general purpose theorem prover
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Uses Model Elimination reasoning method
Contains special purpose reasoners for ontology descriptions
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Being customized for DAML+OIL
Reports –
Errors
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Logical inconsistencies E.g., contradictory type and cardinality constraints object an instance of disjoint classes
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Content structure errors E.g., terms used but not defined
Anomalies
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Missing information E.g., No type constraints on property Class contains no local information
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Redundancies E.g., Redundant superclass and type links
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Extraneous structure or content E.g., Terms defined but not used
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Irregularities E.g., Cyclic subclass links Class with a single subclass Object an instance of a non-leaf class
Summaries E.g., Counts of term references
Suggestions E.g., Use consistent naming conventions Include disjointness constraints
Next steps in our development of Chimaera
Provide interactive follow-up to diagnostics
>
Identify KB content on which diagnosis result is based
>
Suggest repairs or repair strategies; provide user guidance through repair
Reasoning tests that may take substantial time
>
Performed in background
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Results incrementally posted on Web page
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Result summaries sent to user via e-mail when ready
Extend for greater scalability
Axiomatic Semantics for DAML+OIL, RDFS, and RDF
Formal specification of intended meaning
Translates DAML+OIL and RDF into first order logic (FOL)
Produces a logically equivalent ontology in FOL
Facilitates query answering and constraint checking
By traditional theorem provers and problem solvers
Provides specs for special purpose reasoners
Translation method –
Translate DAML+OIL descriptions into RDF statements I.e., into “
Property P of resource R has value V
”
Translate each RDF statement into an FOL sentence I.e., into “
(PropertyValue P S O)
”
Simplify property typing sentences using relation
type
I.e., simplify “
(PropertyValue type S O)
” to “
(type S O)
”
Add axioms from the semantics document
Example –
DAML+OIL description of class
Person
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