Frames add intelligence the data representation

derive d=4. The backward chaining system starts with the goal of finding a value for d and uses the two rules to reduce that to the problem of finding values for a and b.

Forward Chaining

Data		Rules
a=1	IF a=1 & b=2 THEN C=3 IF C=3 THEN d=4			d=4
b=2	IF a=1 & b=2 THEN C=3 IF C=3 THEN d=4			d=4

Subgoals		Rules		Goal
a=1	IF a=1 & b=2 THEN C=3 IF C=3 THEN d=4
b=2	IF a=1 & b=2 THEN C=3 IF C=3 THEN d=4

object	width	color	type

chair #1	3
	2		straight

Frames
mammal

skin

fur	default 4

size	elephant			monkey
size	tusks	type	tail	size

	medium	2

Figure 1.3 Four levels of data representation

Building Expert Systems in Prolog	5

In a furniture placement system each piece of furniture can inherit default values for length. When the piece is placed, demons are activated which automatically adjust the available space where the item was placed.

User Interface

	Chapter 1 - Introduction