<s>
In	O
computer	B-General_Concept
science	I-General_Concept
and	O
operations	O
research	O
,	O
Genetic	B-General_Concept
fuzzy	I-General_Concept
systems	I-General_Concept
are	O
fuzzy	B-General_Concept
systems	I-General_Concept
constructed	O
by	O
using	O
genetic	B-Algorithm
algorithms	I-Algorithm
or	O
genetic	O
programming	O
,	O
which	O
mimic	O
the	O
process	O
of	O
natural	O
evolution	O
,	O
to	O
identify	O
its	O
structure	O
and	O
parameter	O
.	O
</s>
<s>
When	O
it	O
comes	O
to	O
automatically	O
identifying	O
and	O
building	O
a	O
fuzzy	B-General_Concept
system	I-General_Concept
,	O
given	O
the	O
high	O
degree	O
of	O
nonlinearity	O
of	O
the	O
output	O
,	O
traditional	O
linear	O
optimization	O
tools	O
have	O
several	O
limitations	O
.	O
</s>
<s>
Therefore	O
,	O
in	O
the	O
framework	O
of	O
soft	B-General_Concept
computing	I-General_Concept
,	O
genetic	B-Algorithm
algorithms	I-Algorithm
(	O
GAs	O
)	O
and	O
genetic	O
programming	O
(	O
GP	O
)	O
methods	O
have	O
been	O
used	O
successfully	O
to	O
identify	O
structure	O
and	O
parameters	O
of	O
fuzzy	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
Fuzzy	B-General_Concept
systems	I-General_Concept
are	O
fundamental	O
methodologies	O
to	O
represent	O
and	O
process	O
linguistic	O
information	O
,	O
with	O
mechanisms	O
to	O
deal	O
with	O
uncertainty	O
and	O
imprecision	O
.	O
</s>
<s>
With	O
such	O
remarkable	O
attributes	O
,	O
fuzzy	B-General_Concept
systems	I-General_Concept
have	O
been	O
widely	O
and	O
successfully	O
applied	O
to	O
control	O
,	O
classification	O
and	O
modeling	O
problems	O
(	O
Mamdani	O
,	O
1974	O
)	O
(	O
Klir	O
and	O
Yuan	O
,	O
1995	O
)	O
(	O
Pedrycz	O
and	O
Gomide	O
,	O
1998	O
)	O
.	O
</s>
<s>
The	O
construction	O
and	O
identification	O
of	O
a	O
fuzzy	B-General_Concept
system	I-General_Concept
can	O
be	O
divided	O
into	O
(	O
a	O
)	O
the	O
structure	O
and	O
(	O
b	O
)	O
the	O
parameter	O
identification	O
of	O
a	O
fuzzy	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
The	O
structure	O
of	O
a	O
fuzzy	B-General_Concept
system	I-General_Concept
is	O
expressed	O
by	O
the	O
input	O
and	O
output	O
variables	O
and	O
the	O
rule	O
base	O
,	O
while	O
the	O
parameters	O
of	O
a	O
fuzzy	B-General_Concept
system	I-General_Concept
are	O
the	O
rule	O
parameters	O
(	O
defining	O
the	O
membership	O
functions	O
,	O
the	O
aggregation	O
operator	O
and	O
the	O
implication	O
function	O
)	O
and	O
the	O
mapping	O
parameters	O
related	O
to	O
the	O
mapping	O
of	O
a	O
crisp	O
set	O
to	O
a	O
fuzzy	O
set	O
,	O
and	O
vice	O
versa	O
.	O
</s>
<s>
Much	O
work	O
has	O
been	O
done	O
to	O
develop	O
or	O
adapt	O
methodologies	O
that	O
are	O
capable	O
of	O
automatically	O
identifying	O
a	O
fuzzy	B-General_Concept
system	I-General_Concept
from	O
numerical	O
data	O
.	O
</s>
<s>
Particularly	O
in	O
the	O
framework	O
of	O
soft	B-General_Concept
computing	I-General_Concept
,	O
significant	O
methodologies	O
have	O
been	O
proposed	O
with	O
the	O
objective	O
of	O
building	O
fuzzy	B-General_Concept
systems	I-General_Concept
by	O
means	O
of	O
genetic	B-Algorithm
algorithms	I-Algorithm
(	O
GAs	O
)	O
or	O
genetic	O
programming	O
(	O
GP	O
)	O
.	O
</s>
<s>
Given	O
the	O
high	O
degree	O
of	O
nonlinearity	O
of	O
the	O
output	O
of	O
a	O
fuzzy	B-General_Concept
system	I-General_Concept
,	O
traditional	O
linear	O
optimization	O
tools	O
do	O
have	O
their	O
limitations	O
.	O
</s>
<s>
Genetic	B-Algorithm
algorithms	I-Algorithm
have	O
demonstrated	O
to	O
be	O
a	O
robust	O
and	O
very	O
powerful	O
tool	O
to	O
perform	O
tasks	O
such	O
as	O
the	O
generation	O
of	O
fuzzy	O
rule	O
base	O
,	O
optimization	O
of	O
fuzzy	O
rule	O
bases	O
,	O
generation	O
of	O
membership	O
functions	O
,	O
and	O
tuning	O
of	O
membership	O
functions	O
(	O
Cordón	O
et	O
al.	O
,	O
2001a	O
)	O
.	O
</s>
<s>
While	O
genetic	B-Algorithm
algorithms	I-Algorithm
are	O
very	O
powerful	O
tools	O
to	O
identify	O
the	O
fuzzy	O
membership	O
functions	O
of	O
a	O
pre-defined	O
rule	O
base	O
,	O
they	O
have	O
their	O
limitation	O
especially	O
when	O
it	O
also	O
comes	O
to	O
identify	O
the	O
input	O
and	O
output	O
variables	O
of	O
a	O
fuzzy	B-General_Concept
system	I-General_Concept
from	O
a	O
given	O
set	O
of	O
data	O
.	O
</s>
