<s>
In	O
logic	O
,	O
a	O
four-valued	B-Language
logic	I-Language
is	O
any	O
logic	O
with	O
four	O
truth	O
values	O
.	O
</s>
<s>
Several	O
types	O
of	O
four-valued	B-Language
logic	I-Language
have	O
been	O
advanced	O
.	O
</s>
<s>
Nuel	O
Belnap	O
considered	O
the	O
challenge	O
of	O
question	B-Algorithm
answering	I-Algorithm
by	O
computer	O
in	O
1975	O
.	O
</s>
<s>
Belnap	O
proposed	O
a	O
four-valued	B-Language
logic	I-Language
as	O
a	O
means	O
of	O
containing	O
contradiction	O
.	O
</s>
<s>
The	O
logic	O
associated	O
with	O
two-bit	O
variables	O
can	B-Protocol
be	O
incorporated	O
into	O
computer	O
hardware	O
.	O
</s>
<s>
Nine	O
further	O
logical	O
matrices	O
need	O
description	O
to	O
fill	O
out	O
the	O
finite	B-Architecture
state	I-Architecture
machine	I-Architecture
represented	O
by	O
logical	O
matrices	O
acting	O
on	O
X	O
.	O
</s>
<s>
Excluding	O
C	O
,	O
inputs	O
A	O
,	O
B	O
,	O
and	O
D	O
are	O
considered	O
in	O
order	O
and	O
the	O
output	O
in	O
X	O
expressed	O
as	O
a	O
triple	O
,	O
for	O
example	O
ABD	O
for	O
commonly	O
known	O
as	O
the	O
identity	B-Algorithm
matrix	I-Algorithm
.	O
</s>
<s>
A	O
four-valued	B-Language
logic	I-Language
was	O
established	O
by	O
IEEE	O
with	O
the	O
standard	O
IEEE	B-Language
1364	I-Language
:	O
It	O
models	O
signal	O
values	O
in	O
digital	O
circuits	O
.	O
</s>
<s>
This	O
logic	O
is	O
itself	O
a	O
subset	O
of	O
the	O
9-valued	O
logic	O
standard	O
called	O
IEEE	O
1164	O
and	O
implemented	O
in	O
Very	B-Language
High	I-Language
Speed	I-Language
Integrated	I-Language
Circuit	I-Language
Hardware	I-Language
Description	I-Language
Language	I-Language
,	O
VHDL	B-Language
's	O
std_logic	O
.	O
</s>
<s>
One	O
should	O
not	O
confuse	O
four-valued	O
mathematical	O
logic	O
(	O
using	O
operators	O
,	O
truth	O
tables	O
,	O
syllogisms	O
,	O
propositional	O
calculus	O
,	O
theorems	O
and	O
so	O
on	O
)	O
with	O
communication	O
protocols	O
built	O
using	O
binary	O
logic	O
and	O
displaying	O
responses	O
with	O
four	O
possible	O
states	O
implemented	O
with	O
boolean-like	O
type	O
of	O
values	O
:	O
for	O
instance	O
,	O
the	O
SAE	B-Application
J1939	I-Application
standard	O
,	O
used	O
for	O
CAN	B-Protocol
data	O
transmission	O
in	O
heavy	O
road	O
vehicles	O
,	O
which	O
has	O
four	O
logical	O
(	O
boolean	O
)	O
values	O
:	O
False	O
,	O
True	O
,	O
Error	O
Condition	O
,	O
and	O
Not	O
installed	O
(	O
represented	O
by	O
values	O
0	O
–	O
3	O
)	O
.	O
</s>
<s>
On	O
CAN	B-Protocol
,	O
usually	O
fixed	O
data	O
messages	O
are	O
sent	O
containing	O
many	O
signal	O
values	O
each	O
,	O
so	O
a	O
signal	O
representing	O
a	O
not-installed	O
feature	O
will	O
be	O
sent	O
anyway	O
.	O
</s>
<s>
An	O
anticipated	O
demand	O
for	O
data	O
storage	O
in	O
the	B-Operating_System
Internet	I-Operating_System
of	I-Operating_System
Things	I-Operating_System
(	O
IoT	B-Operating_System
)	O
provides	O
a	O
motivation	O
.	O
</s>
<s>
A	O
proposal	O
has	O
been	O
made	O
for	O
32	B-Algorithm
nm	I-Algorithm
process	I-Algorithm
application	O
using	O
a	O
split	O
bit-gate	O
:	O
"	O
By	O
using	O
CNFET	O
technology	O
in	O
32	B-Algorithm
nm	I-Algorithm
node	O
by	O
the	O
proposed	O
SQI	O
gate	O
,	O
two	O
split	O
bit-lines	O
QSRAM	O
architectures	O
have	O
been	O
suggested	O
to	O
address	O
the	O
issue	O
of	O
increasing	O
demand	O
for	O
storage	O
capacity	O
in	O
IoT/IoVT	O
applications	O
.	O
</s>
