Information Technology Reference
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A semantic network
is a graph
<
V
,
E
>
with labeled nodes and arcs, where
V
and
E
are sets of
nodes and arcs, respectively. The nodes can represent objects (concepts, events, actions, etc.)
of a problem domain, and the arcs represent relations between them.
By
Pv
, we denote the set of properties of an object
v
∈
V
.
Objects
v
,
v
'
∈
V
intersect
each other on SN if and only if
Pvv
' =
Pv
∩
Pv
' ≠ , where
Pvv
'
is a
set of common properties of objects
v
and
v
'.
By
Vp
, we denote a set of SN objects that have a property
p
.
By
Vv
,
Vv
V
, we denote an object set of objects that intersect
v
∈
V
.
The object
C
is
an intersection for
A
if and only if there is (
C
V
) & (
p
PC
) & (
nR
nC
) &
(
nR
<<
nC
) & (
nRC
<
nR
) & (
nRC
>1), where
nR
and
nC
are the numbers of properties of the
receiver
R
and the intersection
C,
respectively;
nRC
is the number of their common
properties,
￢
(
nR
<<
nC
) denotes that receiver
R
should not be much smaller than
intersection
C
(i.e., the possibility of absorbing the receiver
R
by the intersection
C
, since
here the probability of receiving a false analogy increases).
The object
O
is
the source for analogy
A
if and only if there is (
O
V
) & (
p
PO
) & (
nO
nC
) &
(
nO
<<
nC
) & (
nOC
<
nO
) & (
nOC
>1), where
nO
is the number of properties of the source
O
;
nOC
is the number of common properties of the source
O
and intersection
C
; and other
notations are analogous to the previous definition.
By
VC
,
VC
Vp
, we denote the set of objects that are candidates for the role of intersection
C
for analogy
A
.
By
VO
Vp
, we denote the set of objects that are candidates for the role of source
O
for
analogy
A
.
By
VA
, we denote the set of analogies
A
.
The set
POCR
=
PO
PC
PR
denotes
the context
, with respect to which analogy
A
is
considered.
We consider the structure of the SN in detail (for Metalevel and for Situation 1) using the
example from power engineering - operation control of the nuclear power unit (Fig. 3)
[Eremeev et al., 2006a].
Let us give a semantic interpretation of the information given in the SN for Situation 1:
It is recommended to supply the pump TH11D01 with boric concentrate 40g/kg caused
by switching off automatic cooling system ACS 1 due to closing the gates TH11S24 and
TH11S25;
ACS 2 is switched off due to the closed gates TH12S24 and TH12S25;
The upper setting T517B01 is equal to 63;
The lower setting T517B01 is equal to 56;
The upper setting TH11T500 is equal to 60;
The lower setting TH11T500 is equal to 20.
Analogously, the fragments of the SNs, which illustrates Situations 2,3,4, are represented in
Fig. 4.
2.2 Algorithm of reasoning by structural analogy
An SN with information about the problem domain, a receiver
R
, and the property for
defining the original context
p
provide input data for this algorithm.
The algorithm for the problem solution on the basis of analogy taking into account the context
consists of the following steps:
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