1. 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  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 – >Frames with inherited values and constraints >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 >Uses Model Elimination reasoning method  Contains special purpose reasoners for ontology descriptions >Being customized for DAML+OIL  Reports –  Errors >Logical inconsistencies E.g., contradictory type and cardinality constraints object an instance of disjoint classes >Content structure errors E.g., terms used but not defined  Anomalies >Missing information E.g., No type constraints on property Class contains no local information >Redundancies E.g., Redundant superclass and type links >Extraneous structure or content E.g., Terms defined but not used >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 >Results incrementally posted on Web page >Result summaries sent to user via e-mail when ready  Extend for greater scalability  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 and person Joe  Translation into RDF statements: (type Class Person) (subClassOf Person Animal) (type Restriction R) (restrictedBy Person R) (onProperty R parent) (toClass R Person) (type Joe Person) (parent Joe John)  Translation into first order logic: (Type Class Person) (PropertyValue subClassOf Person Animal) (Type Restriction R) (PropertyValue restrictedBy Person R) (PropertyValue onProperty R parent) (PropertyValue toClass R Person) (Type Joe Person) (PropertyValue Parent Joe John)  Primary axiom for toClass – “If object R is a value of restrictedBy for object C1, object P is a value of onProperty for R, and object C2 is a value of toClass for R, then for all objects I and V, if I is of type C1 and V is a value of P for I, then V is type C2.” (=> (and (PropertyValue restrictedBy ?c1 ?r) (PropertyValue onProperty ?r ?p) (PropertyValue toClass ?r ?c2)) (forall (?i ?v) (=> (and (Type ?i ?c1) (PropertyValue ?p ?i ?v)) (Type ?v ?c2))))  Is John a Person ? >Use axiom to infer – (forall (?i ?v) (=> (and (Type ?i Person) (PropertyValue parent ?i ?v)) (Type ?v Person))) >And then infer – (Type John Person) >“Yes”, John is a Person. The Chimaera Ontology Tool Suite A Knowledge Evolution Environment Axiomatic Semantics for DAML+OIL, RDFS, and RDF