Information Technology Reference
In-Depth Information
W
θ
' = W
ξθ
, then (Q,
θ
) is more intensive than (Q',
θ
'), written as (Q,
θ
)
≥
(Q',
ȶ
').
Definition 5.4
(Maximal Partial Match ) (Q,
θ
) is a maximal partial match of
s × t if for any partial match of s × t, (Q',
θ
') such that (Q,
θ
)
²
(Q',
θ
').
Definition 5.5
(Analogical Learning)
Suppose s
1
, s
2
∈
S, t
1
∈
T,
β
∈
S × S, s
1
×
s
2
∈
Ȳ
, and m is a maximal partial match of s
1
× t
1
. Analogical learning is the
process of finding a t
2
such that t
2
∈
T on the basis of facts t
1
× t
2
∈
β
and that
m is a maximal partial match of s
2
× t
2
.
5.3 Process Model
CBR is a kind of analogical reasoning. When a new problem is encountered, a
set of similar cases are retrieved from memory according to some properties
of the target case. But the result is coarse, might not be correct, we must
verify their similarities, which makes us further explore more details of the
target and potential base cases. Actually, some analogical mapping has
already been carried out locally and tentatively at this stage. After this process,
the potential base cases have already been arranged in an partial order
according to the similarity with the target cases. We enter the stage of
analogical mapping. We choose the most similar base case from the potential
base case set, and construct a one-to-one mapping between them. In the next
step, we get a complete (or partial) solution to the new problem by utilizing
this mapping and the solution of the base case. If the solution is a partial one,
then add it to the initial descriptions of the target case and restart a new round
of the whole analogy course. In the case that the suggested solution is not a
valid solution to the target case, an explanation on the reason why it fails is
given and the system will evoke the mending module to revise the suggested
solution to get an confirmed one, which provides an opportunity to learn from
failure. The system should record reasons to fail, in order to avoid the same
mistakes in future. Finally, the evaluation on the validity of the analogical
reasoning should be given. The whole analogy course is carried on in an
accumulative manner. Fig. 5.2 sketches the general structure of CBR.
