Techniques of knowledge representation

Semantic networks may be used to represent knowledge. Each node represents a concept and arcs are used to define relations between the concepts.

From the 1960s, the knowledge frame or just frame has been used. A frame consists of slots which contain values; for instance, the frame for house might contain a color slot, number of floors slot, etc.

Frames can behave something like object-oriented programming languages, with inheritance of features described by the "is-a" link. However, there has been no small amount of inconsistency in the usage of the "is-a" link: Ronald J. Brachman wrote a paper titled "What IS-A is and isn't", wherein 29 different semantics were found in projects whose knowledge representation schemes involved an "is-a" link. Other links include the "has-part" link.

Frame structures are well-suited for the representation of schematic knowledge and stereotypical cognitive patterns. The elements of such schematic patterns are weighted unequally, attributing higher weights to the more typical elements of a schema. A pattern is activated by certain expectations: If a person sees a big bird, he or she will classify it rather as a sea eagle than a golden eagle, assuming that his or her "sea-scheme" is currently activated and his "land-scheme" is not.

Frames representations are more object-centers than semantic networks: All the facts and properties of a concept are located in one place - there is no need for costly search processes in the database.

Frames suffer from the frame problem of knowledge linking.

A script is a type of frame that describes what happens temporally; the usual example given is that of describing going to a restaurant. The steps include waiting to be seated, receiving a menu, ordering, etc.

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