Information Technology Reference
In-Depth Information
10.2.1 Domain-specific Inversion
Domain-specific inversion is similar to the inversion operator that works in
the heads of genes, with the difference that it operates either within Dw
(Dw-specific inversion) or Dt (Dt-specific inversion). Thus, these operators
randomly choose the chromosome, the gene with its Dw/Dt to be modified,
and the start and termination points of the sequence to be inverted.
Consider, for instance, the chromosome below with
h
= 6 (Dw and Dt are
shown in different shades):
0123456789012345678
901234567890123456
789012
TDUDcTddccabdddadbd
806945439040167431
793
0
59
where “U” represents a function of one argument and “T” represents a func-
tion of three arguments. Suppose that the sequence “5439” in Dw and the
sequence “93” in Dt were chosen to be inverted, giving:
0123456789012345678
901234567890123456
789012
TDUDcTddccabdddadbd
806949345040167431
739
0
59
Suppose now that the arrays below represent the weights and the thresholds
of both chromosomes:
W = {0.701, 1.117, 0.148, -0.94, -0.044, 1.124, -1.575, 0.877, -1.22, 1.614}
T = {-1.756, -1.776, 0.825, 0.628, -0.263, 0.127, 0.965, -1.651, -0.894, -1.078}
As you can see by their expression in Figure 10.1, they encode very different
neural networks because the weights and the thresholds are moved around
by the inversion operator, creating new neurons with different strengths and
responses.
10.2.2 Domain-specific Transposition
Domain-specific transposition is restricted to the NN-specific domains, that
is, Dw and Dt. Its mechanism, however, is similar to IS transposition. This
operator randomly chooses the chromosome, the gene with its respective
Dw or Dt, the first and last positions of the transposon, and the target site
(obviously also chosen within Dw or Dt). Then it moves the transposon from
the place of origin to the target site.
Consider, for instance, the chromosome below with
h
= 4 (Dw and Dt are
shown in different shades):
