Frames

Frames

Organize property and ISA knowledge by subject concept rather than independent triples, in a frame hierarchy.

(bird isa animal)
(bird can-fly yes)
(canary isa bird)
(canary color yellow))
(tweety isa canary)

(bird (animal) (can-fly yes))

(canary (bird) (color yellow))

(tweety (canary))

Frame structure

(name (...abstractions) ...slots)

• Name, e.g., Tweety
• Immediate abstractions, e.g., bird and pet
• Slots. Each slot has
  • a role, e.g., age, color, ...
  • a filler, e.g., 12, yellow, ...
  • filler can be the name of another frame

Frames not just for objects

• Things: dog, human, John, Tweety
• Actions: flying, eating, writing
• Events: tweety-flew, clyde-ate-peanuts
• States and state changes: is-ill, rates-rising
• Causal sequences: bottle-fell-caused-bottle-broke
• Scripts: going-to-restaurant, visit-patient-in-hospital
• ...and everything else

Event frames

General event pattern:

(eat-event (event) (actor animal) (object food))

Specific event

(eat-event-1 (eat-event) (actor clyde-1) (object peanuts-1))

Causal sequence

(causal-1 (causal)
  (antecedent eat-event-1) (consequent ill-state-1))

Similarity

• When is a frame A is more similar to frame B than to frame C?
• Many methods used (see this article)
• An important idea is the "most specific common abstraction" (MSCA)
  • The MSCA of A and B is the most specific concept above A and B
  • There may be several MSCAs when multiple inheritance is involved

Generalization

• Given similar frames A and B, form a new frame that
  • has the MSCAs of A and B as its abstractions
  • becomes an abstraction of A and B
  • contains the slots shared by A and B
    • slot fillers are the MSCA's of the fillers in A and B