Table of Contents
Formal Aspects Of Protege
Overview
Proposed HPKB Scenario
Knowledge Bases in HPKB
Interoperability requires Semantics
Knowledge Models
Knowledge Models at SMI
Example: Protégé and Loom
Frame-Based Knowledge Models
What’s a Slot ?
What’s an Instance ?
Interoperation ?
Protégé-2000 Is Like HPKB
Components
Widgets
Storage Models
Axioms and Constraints
The Actual Knowledge Model
Knowledge Models
The Role of Logic
KIF
Frames
Classes
Defining Subclasses
Multiple Inheritance
Slots
Attaching a Slot
Slots Propagation
Restating this in KIF
Restating this in English
Restating this in Swedish
Instances
Facets
Facet Restrictions
Facet Propagation
Canonical Facets
OKBC Revisited
Desiderata for a Constraint Language
Overview
Constraints
Desiderata for the Language
The Big Modular Picture of Protege
Full and formal semantics
Compatibility with the OKBC knowledge model
Ease of Translation
Supported by a reasonable default implementation
A Deficient Syllogism
Human Readability is a Red Herring
The Constraint Language
A Single Constraint Language
Logic
Sorted Logic
Reified Constraints
The Constraint KB
PPT Slide
Constraints and Axioms
Multiple Interpretations of a Single Theory:
New functions and predicates are implemented
procedurally
PPT Slide
Universal Implementation Decisions
The Language is defined in a Knowledge-Base
Enforcement of constraints is not necesarily
real-time
Enforcement via plug-ins (and tabs)
Two Important Consequences of these Decisions
What is a knowledge base ?
We have evolved from OKBC to some extent
The Default Implementation
Model-checking, rather than theorem proving
Envisioned: Constraints are mostly Local
Dimensions for Evolution
Richer axiom ontology
More Predicates and Functions
Other engines
Support for Knowledge-Acquisition
Subclassing the PAL Ontology to provide hooks for
widgets ?
“No A is a B”
Let’s write it in PAL
This is really a Venn Diagram
Widgets play a role here:
Things that are done:
Things that we will do: |