Information Technology Reference
In-Depth Information
5.4.2 Dc-specific Inversion
The Dc-specific inversion is similar to the inversion operator that works in the
heads of genes, with the difference that it is restricted to the Dc domain.
Thus, this operator randomly chooses the chromosome, the gene with its
respective Dc to be modified, and the start and termination points of the
sequence to be inverted. Typically, a small inversion rate of 0.1 is used as
this operator is seldom used as the only source of genetic variation.
Consider, for instance, the two-genic chromosome below with
h
= 5:
0123456789012345601234567890123456
*+/+/a?a??a
4073
09+++*+??a???737256
(5.8)
and its arrays of random numerical constants:
C
1
= {1.227, 1.361, 0.512, 1.467, 1.666, 1.901, -1.583, 1.338, 0.620, -1.180}
C
2
= {-0.286, -1.551, -1.165, 0.783, -1.872, 0.064, 1.152, -1.066, 1.343, 1.851}
Suppose now that the sequence “4073” in gene one was chosen to be in-
verted, giving:
0123456789012345601234567890123456
*+/+/a?a??a
3704
09+++*+??a???737256
(5.9)
As you can see in Figure 5.5, the program encoded in this new chromosome
is slightly different from the one encoded in the parent chromosome. Note
that, as a result of this event of inversion, not only a new numerical constant
(the constant 1.467) is incorporated in the daughter tree but also a different
combination of old numerical constants is tested (constants 1.338 and 1.277).
5.4.3 Dc-specific Transposition
The Dc-specific transposition is similar to the IS transposition that operates in
the head/tail domain of genes, with the difference that it is restricted to the
Dc domain. Thus, this operator randomly chooses the chromosome, the gene
with its respective Dc to be subjected to transposition, the start and termina-
tion points of the transposon, and the target site; then it moves the transposon
from the place of origin to the target site. Typically, a small transposition rate
of 0.1 is used as this operator is usually used together with other, more pow-
erful genetic operators.
