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instead of just enumerating the operable predicates. Rules and facts (premises)
are needed to make inferences. This involves some techniques about meta-level
programming and the system should be capable of treating with meta-rule. But
Turbo Prolog does not support meta-level programming, if operationality
criterion is defined as dynamic; some meta-level predicates should be
implemented in the system which makes the system support meta-level
knowledge. Thereafter we define the operationality criterion as static temporally
and store some predefined predicates into inner database.
The aim of operationality criterion is that the learned concept is expected to
improve the efficiency of system. Someone believes that if a concept description
can be effectively applied to recognize corresponding instance, it will be operable.
However the concept description can not only be applied to recognize instance
but also space index and so on thus the above viewpoint is not perfect.
Keller defined operationality criterion as follows(Keller, 1987)
Given
A concept description
A performance system that makes use of the description to improve
performance
Performace
objectives
specifying
the
type
and
extent
of
system
improvement desired.
Then the concept description is operable if it satisfies the following
conditions:
(1) Useable: the execution system can take advantage of the concept description.
(2) Effectiveness: when the concept description is adopted by the execution
system, the execution of system can be improved according to the requirements.
Figure 9.13 illustrates a generalization explanation structure of Safe-to-
Stack(
x, y
).
Safe-to-Stack
(x, y)
Lighter
(x, y)
Weight
(x, w)
<(w, 10)
Weight
(y, 10)
Operationality
criterion
volume
(x, y)
Density
(x, d)
X
(v, d, w)
Isn
(y, rect-solid)
Made-of
(y, lucite)
Made-of
(x, m)
Sepc-Grav
(m, d)
Figure 9.13. Prune of operationality criterion
