Information Technology Reference
In-Depth Information
Example 2.6.3.
The electric circuit of Example 2.3.2, depicted in Fig. 2.4,
is slightly modied and further augmented by a light detecting device that
becomes and stays activated as soon as light turns on; see Fig. 2.8. Accord-
ingly, the basic action domain of Example 2.3.2 is extended by fluent name
detect
0
. The new arrangement is formalized by these four state constraints:
light
up
(
s
1
)
^
up
(
s
2
)
relay
up
(
s
1
)
^
up
(
s
3
)
(2.13)
relay
:
up
(
s
2
)
light
detect
Obviously, potential influence is as in our predecessor circuit but with
additionally having that the state of the light bulb may aect the de-
tector. After enhancing influence information
I
of Example 2.3.2 by pair
(
light
;
detect
), the above state constraints determine the following causal
relationships
R
according to our generation procedure.
up
(
s
1
) causes
light
if
up
(
s
2
)
up
(
s
2
) causes
light
if
up
(
s
1
)
:
(
s
1
) causes
:
if
>
:
(
s
2
) causes
:
if
>
up
light
up
light
up
(
s
1
) causes
relay
if
up
(
s
3
)
up
(
s
3
) causes
relay
if
up
(
s
1
)
:
up
(
s
1
) causes
:
relay
if
>
:
up
(
s
3
) causes
:
relay
if
>
relay
causes
:
up
(
s
2
)if
>
light
causes
detect
if
>
Now, suppose we toggle the rst switch,
s
1
, in the state depicted in Fig. 2.8.
What is the expected outcome? Obviously, the relay gets activated and, then,
:
up
(
s
1
)
up
(
s
2
)
:
light
R
:
detect
:
relay
up
(
s
3
)
Figure 2.8.
A modied electric circuit (c.f. Fig. 2.4) augmented by a device, repre-
sented by fluent
detect
, which registers an activation of the light bulb (this device
combines a phototransistor and flipflop). It is assumed that no action of light has
occurred yet.
