Information Technology Reference
In-Depth Information
the tuples and make consistent filtering to them. Those filtered here are denoted
by W.
According to DERIV(
Y,V
):
(I
4
,I
5
)
C
(I
8
,I
5
)
W
(I
4
,I
6
)
C
(I
8
,I
6
)
(I
4
,I
7
)
(I
8
,I
7
)
C
(I
4
,I
9
)
W
(I
8
,I
9
)
C
According to DERIV(
V,A
):
(I
5
,I
1
)
C
(I
7
,I
1
)
(I
6
,I
1
)
(I
9
,I
1
)
C
Among that, in tuple(I
4
,I
5
), I
4
makes the qualitative state of Y transit to
<(0,
¯
),inc>, while I
5
makes the qualitative state of V transit to <0,std>, which is
not consistent with constraint(Y,V). So (I
4
,I
5
) is filtered out. The I
9
in tuple (I
4
,I
9
)
and (I
9
,I
1
) are both the transitions to V . As (I
9
,I
1
) has already been filtered out,
(I
4
,I
9
) is also filtered out.
The left tuples have formed two global explanations as following:
Y V A
I
4
I
7
I
1
I
8
I
6
I
1
The first explanation has no transition and is filtered out. The second
explanation is the only subsequent state. Now:
QS(
A,t
1
)<
g
, std>
QS(
V,t
1
)<0,dec>
Y
max
,std>
Among that, Y
max
is the new landmark value.
QS(
Y,t
1
)<
4.6 Algebra Approach
Williams has built a mixed algebra combined qualitative with quantitative and
realized the corresponding symbol algebra program MINIMA, which is the
qualitative simulation of MACSYMAproviding a tool for simplifying,
decomposing and combining qualitative equations(Williams, 1988). The design
of one kind of physical problems can be handled by this algebra system.
