Database and Expert System Technology - Information Systems Reengineering, Integration and Normalization - page 76

Fig. 2.18 A slot-filler in KAPPA frame based system

OR, and AND in the formulation of restrictions on slots. For example, you can put
the following restriction on the gender slot associated with the member frame to
represent a school for girls. Members of school are students and staff. Most of them
are female.

( gender (default female) (restrict (OR male female) ))

Procedural attachment may also be used here for constraints or monitors. There
is one type of procedure called a “demon” which is a restriction (constraint) or
integrity function that is called whenever the slot in question receives a value or is
updated.
Implementing reasoning is a complex process in frame-based systems. Most
frame-based inference mechanisms are based on the structural properties of frames
and taxonomies. There are five major mechanisms that can be used for reasoning in
frame-based systems (Reichgelt 1991 ).

• Matching

This mechanism concerns taking a decision as to which of the many frames in
the knowledge base is applicable to the current situation. The system must com-