Knowledge Representation Formalisms

e.g If we know that Fred is a bird we might deduce that Fred can fly. Later we might discover that Fred is an emu.

  • Modularity is sacrificed. Changes in knowledge base might have far-reaching effects.
  • Cumbersome control information.

The following properties should be possessed by a knowledge representation system.
Representational Adequacy -- the ability to represent the required knowledge;

Inferential Adequacy - the ability to manipulate the knowledge represented to produce new knowledge corresponding to that inferred from the original;

Inferential Efficiency - the ability to direct the inferential mechanisms into the most productive directions by storing appropriate guides;

Acquisitional Efficiency - the ability to acquire new knowledge using automatic methods wherever possible rather than reliance on human intervention.

To date no single system optimises all of the above. We will discuss in this module two formalisms, namely, semantic networks and frames, which trades off representational adequacy for inferential and acquisitional efficiency.