Protégé-2000:
    A Flexible and Extensible
Ontology-Editing Environment

                       Natalya F. Noy,
     Monica Crubézy, Ray W. Fergerson,
            Samson Tu, Mark A. Musen

            Stanford Medical Informatics
                     Stanford University
                           Stanford, CA
Facts (maybe)
Fact 1: Ontologies are no longer just for
  knowledge engineers
Fact 2: A number of new Semantic-Web
  languages and representation formalisms are
  emerging; no agreement yet
Fact 3: We are developing ontologies, agents, and
  applications today, without waiting for the
  standards
Facts and Requirements
n   Facts:                            n   Requirements:
    n   Ontologies are no longer          n   Domain experts need to
        just for knowledge                    understand and maintain
        engineers                             ontologies
    n   A number of new                   n   We need adaptable tools
        Semantic-Web languages                which we can tune to
        and representation                    support new languages
        formalisms are emerging;              and formalisms quickly
        no agreement yet                  n   We need suites of tools for
    n   We are developing                     ontology development and
        ontologies, agents, and               management
        applications today, without
        waiting for the standards
A Solution
n   Protégé-2000 is an ontology-editing and
    knowledge-acquisition environment, which has
    n   a graphical and easy-to-use interface
    n   a flexible knowledge model
    n   an extensible plugin architecture
    n   an existing set of plugins for
         n   ontology merging
         n   acquisition of information from online knowledge sources
         n   constraint specification and verification
         n   …. (we don’t even know them all)
Protégé-2000 Knowledge-Model
Components
n   Classes
     concepts in a taxonomic hierarchy
n   Instances
     instances of classes
n   Slots
     first-class objects representing properties of classes
     and instances
n   Facets
     constraints on allowed slot values, such as cardinality,
     defaults, allowed classes, and so on.
Ontologies in Protégé-2000
Acquiring instance data
Protégé-2000 Architecture

     Knowledge               Storage
       model                  model




                   User
                 interface
Changing the Knowledge Model
Changing the Knowledge Model
n   Templates for new
    class-level and slot-
    level properties
    n  metaclasses
    n  metaslots
Changing the Knowledge Model
n   Templates for new
    class-level and slot-
    level properties
    n  metaclasses
    n  metaslots
Protégé-2000 Plugin Architecture
• URIs
• Complex expressions
• Primitive and defined classes
• Transitive, symmetric properties

                     Knowledge                   Storage
                       model                      model




                                       User
                                     interface
Changing The User Interface
n   Users can replace any widget on the form with a
    different one.
Changing The User Interface
n   Users can replace any widget on the form with a
    different one.
Protégé-2000 Plugin Architecture
• URIs
• Complex expressions
• Primitive and defined classes
• Transitive, symmetric properties

                       Knowledge                 Storage
                         model                    model




                                       User
                                     interface
• Acquire and verify URIs
• Use a structured editor
   for logical expressions
• Display inferred values
   for transitive properties
Changing The Storage Model
n   Users can change the output file
    format - alternative “back ends”
n   The back-end code can
    n   resolve the remaining differences in
        the knowledge model,
    n   add or remove information,
    n   map between Protégé knowledge
        model and the required knowledge
        model
Protégé-2000 Plugin Architecture
                                                           • RDF Schema
• URIs
                                                           • OIL
• Complex expressions
                                                           • XML
• Primitive and defined classes
                                                           • JDBC database
• Transitive, symmetric properties

                       Knowledge                 Storage
                         model                    model




                                       User
                                     interface
• Acquire and verify URIs
• Use a structured editor
   for logical expressions
• Display inferred values
   for transitive properties
Including New Applications


  Knowledge               Storage
    model                  model    API
                                           Other KB
                                          applications
                User
              interface
Include New Applications
Integration With
A Description
Logics Classifier
(FaCT)
Using A DL Classifier
Other Plugins
n   Diagrammatic knowledge entry
n   Ontology visualization
n   Ontology merging
n   Ontology acquisition from UMLS and
    WordNet
n   Constraint verification

All these plugins become automatically
  available for different languages
As A Result, We Get A Tool That
n   can be used for ontology development in
    different (overlapping) representation formalisms
    n   translate models from one formalism to another
n   can be easily customized to a new language
    n   knowledge model
    n   user interface
    n   persistent storage
n   can incorporate other applications
Our Vision
n   Complex, distributed systems built from plug-
    and-play components
n   Systems that allow evolution throughout their life
    cycles via substitution of new components
n   Repositories of components for use in new
    designs and for updating previous applications

       for both ontologies and components
           of knowledge-based systems!
http://protege.stanford.edu