Information Technology Reference
In-Depth Information
Glands
Receptors
Enzymes
…
…
…
θ
θ
1
n
1
n
Gene
Activity
strength
…
shape
shape
strength
Specificity List
Figure 3.8
Genotype layout. The genotype defines which enzymes are present in
an enzyme system. All genotypes declare a full set of terminal enzymes (glands and
receptors). Note that glands do not have specificities, for they receive no input from
other enzymes.
transfer and remove
, attempts to capture some of the evolutionary behaviors
induced by biological reproduction but does not use a biomimetic mechanism.
Uniform crossover is a two-stage process of gene recombination followed
by gene shuffling (Figure 3.10). Gene recombination resembles meiosis, the bi-
ological process whereby maternal and paternal DNA is recombined to produce
germ cells. Gene recombination involves selecting and recombining a number
of pairs of similar genes from the parent genomes. Pairs of genes are selected
according to the similarity of the functionalities of their enzyme products. Re-
combination involves specificity recombination, where pairs of functionalities
are recombined using standard GA uniform crossover, followed by specificity
shuffling, where the recombined specificities are divided uniformly between
the child genes. Gene shuffling then divides the recombined genes uniformly
between the child genotypes.
A general view of recombination in natural systems is that it changes the
genetic makeup of a parent genome by adding some new genes and removing
some existing genes. Transfer and remove (TR) crossover is based on this idea.
A TR crossover event generates a child solution by either copying a contiguous
Population
Crossover
Mutation
>
elite
m
emigrant
OUT
IN
X
immigrant
Figure 3.9
Genetic algorithm structure, showing the processing that occurs in each
cell of the distributed population during each generation.
