1 Frame Theory A vague paradigm - to organize knowledge in high-level structures “A Framework for Representing Knowledge” - Minsky, 1974 Knowledge is encoded in packets, called frames (single frames in a film) Frame name + slots

2 Frame Theory Example: (defineType Animals (alive T) (flies F) ) (defineInstance Tweety (type Animals) (name "Tweety") )

3 Frame Theory (defineType Birds (super-typeAnimals (legs 2) (flies T) ) (defineType Mammals (super-type Animals) (legs 4) )

4 Frame Theory (defineType Penguins (super-typeBirds (flies F) ) (defineType Cats (super-type Mammals) ) (defineType Bats (super-type Mammals) (legs2) (fliesT) )

5 Frame Theory (defineInstance Opus (typePenguins (name "Opus") (friendBill) ) (defineInstance Bill (type Cats) (name"Bill") (friend Opus) ) (defineInstance Pat (typeBats (name "Pat") )

6 Frame Theory Overriding Inheritance Multiple Inheritance (defineType Pigeons (super-typeBirds )

7 Frames and Semantic Networks Animals Alive Flies T F Birds Legs Flies 2 T Mammals Legs 4 Penguins Flies F CatsBats Legs Flies 2 T Opus Name Friend Opus Bill Name Friend Bill Pat Name Pat member subset

8 Frames and FOL (defineType Animals (alive T) (flies F) ) Rel(Animals, alive, T) Rel(Animals, flies, F)

9 Frames and FOL (defineInstance Opus (typePenguins (name "Opus") (friendBill) ) type(Opus, Penguins) name(Opus, "Opus") friend(Opus, Bill)

10 Frames and FOL Hybrid systems:  Frame component: to define terminologies (predicates and terms)  Predicate calculus component: to describe individual objects and rules

11 Frames and OO Languages Parallel developments:  Frames: languages to construct AI knowledge bases  OO Languages: practical programming languages OO languages encapsulate object declarations and object operations.

12 Exercises Reading: Sections in Sowa’s KR Exercise 3 - Chapter 3 - in Sowa’s KR