<s>
For	O
holographic	B-Algorithm
data	I-Algorithm
storage	I-Algorithm
,	O
holographic	B-Algorithm
associative	I-Algorithm
memory	I-Algorithm
(	O
HAM	O
)	O
is	O
an	O
information	O
storage	O
and	O
retrieval	O
system	O
based	O
on	O
the	O
principles	O
of	O
holography	B-Algorithm
.	O
</s>
<s>
Holograms	B-Algorithm
are	O
made	O
by	O
using	O
two	O
beams	O
of	O
light	O
,	O
called	O
a	O
"	O
reference	O
beam	O
"	O
and	O
an	O
"	O
object	O
beam	O
"	O
.	O
</s>
<s>
Afterwards	O
,	O
by	O
reproducing	O
the	O
reference	O
beam	O
,	O
the	O
hologram	B-Algorithm
recreates	O
a	O
visual	O
image	O
of	O
the	O
original	O
object	O
.	O
</s>
<s>
It	O
can	O
be	O
thought	O
of	O
as	O
an	O
artificial	B-Architecture
neural	I-Architecture
network	I-Architecture
which	O
mimics	O
the	O
way	O
the	O
brain	O
uses	O
information	O
.	O
</s>
<s>
It	O
can	O
be	O
considered	O
as	O
a	O
complex	O
valued	O
artificial	B-Architecture
neural	I-Architecture
network	I-Architecture
.	O
</s>
<s>
The	O
holographic	B-Algorithm
associative	I-Algorithm
memory	I-Algorithm
exhibits	O
some	O
remarkable	O
characteristics	O
.	O
</s>
<s>
At	O
the	O
heart	O
of	O
this	O
new	O
memory	O
lies	O
a	O
novel	O
bi-modal	O
representation	O
of	O
pattern	O
and	O
a	O
hologram-like	O
complex	O
spherical	O
weight	O
state-space	O
.	O
</s>
<s>
It	O
is	O
based	O
on	O
principle	O
of	O
information	O
storage	O
in	O
the	O
form	O
of	O
stimulus-response	O
patterns	O
where	O
information	O
is	O
presented	O
by	O
phase	B-Application
angle	I-Application
orientations	O
of	O
complex	O
numbers	O
on	O
a	O
Riemann	O
surface	O
.	O
</s>
<s>
The	O
mathematical	O
basis	O
requires	O
no	O
optimization	O
of	O
parameters	O
or	O
error	O
backpropagation	B-Algorithm
,	O
unlike	O
connectionist	O
neural	B-Architecture
networks	I-Architecture
.	O
</s>
<s>
HAM	O
typically	O
employs	O
sigmoid	B-Algorithm
pre-processing	O
where	O
raw	O
inputs	O
are	O
orthogonalized	O
and	O
converted	O
to	O
Gaussian	B-Application
distributions	O
.	O
</s>
<s>
No	O
backpropagation	B-Algorithm
of	O
error	O
terms	O
or	O
iterative	O
processing	O
required	O
.	O
</s>
<s>
The	O
generated	O
phase	B-Application
angle	I-Application
communicates	O
response	O
information	O
,	O
and	O
magnitude	O
communicates	O
a	O
measure	O
of	O
recognition	O
(	O
or	O
confidence	O
in	O
the	O
result	O
)	O
.	O
</s>
