Next: Objects and agents
Up: The range of representable
Previous: Actions
In addition to actions, a variety of states are
representable within this knowledge scheme.
There are two forms to the states which are represented
in the knowledge system. First, states can simply
indicate that there is a relationship between other
objects in the knowledge structure. Consider the
Zoo spaceship. The concepts of
spaceship and hugo are related by the
state owner-of. Thus, there needs to be a
frame in the system which captures this concept, as
shown in Figure 8.
Each state which acts only as a relation merely
contains two
primary attributes, a domain
and a co-domain.
Figure 8:
Partial representation of the owner-of state relation
|
The other form of state which is representable are descriptions
of objects which act to enable or stop various actions
from occurring. For example, in Figure 9,
the state concept of alert is shown. For these
states, it is necessary to know what actions they
have been instrumental in helping to achieve; thus,
they contain a participated-in primary
attribute. It is also necessary to maintain a link
to the entity which contained this state; this
is accomplished through the object attribute.
Figure 9:
Partial representation of the alert state
|
Next: Objects and agents
Up: The range of representable
Previous: Actions
Kenneth Moorman
11/4/1997