<s>
In	O
artificial	B-Application
intelligence	I-Application
,	O
a	O
procedural	B-Application
reasoning	I-Application
system	I-Application
(	O
PRS	O
)	O
is	O
a	O
framework	O
for	O
constructing	O
real-time	O
reasoning	B-Application
systems	I-Application
that	O
can	O
perform	O
complex	O
tasks	O
in	O
dynamic	O
environments	O
.	O
</s>
<s>
It	O
is	O
based	O
on	O
the	O
notion	O
of	O
a	O
rational	O
agent	O
or	O
intelligent	B-General_Concept
agent	I-General_Concept
using	O
the	O
belief	O
–	O
desire	O
–	O
intention	O
software	O
model	O
.	O
</s>
<s>
Each	O
knowledge	O
area	O
is	O
a	O
piece	O
of	O
procedural	O
knowledge	O
that	O
specifies	O
how	O
to	O
do	O
something	O
,	O
e.g.	O
,	O
how	O
to	O
navigate	O
down	O
a	O
corridor	O
,	O
or	O
how	O
to	O
plan	B-Algorithm
a	I-Algorithm
path	I-Algorithm
(	O
in	O
contrast	O
with	O
robotic	O
architectures	O
where	O
the	O
programmer	B-Application
just	O
provides	O
a	O
model	O
of	O
what	O
the	O
states	O
of	O
the	O
world	O
are	O
and	O
how	O
the	O
agent	O
's	O
primitive	O
actions	O
affect	O
them	O
)	O
.	O
</s>
<s>
Such	O
a	O
program	O
,	O
together	O
with	O
a	O
PRS	O
interpreter	B-Application
,	O
is	O
used	O
to	O
control	O
the	O
agent	O
.	O
</s>
<s>
The	O
interpreter	B-Application
is	O
responsible	O
for	O
maintaining	O
beliefs	O
about	O
the	O
world	O
state	O
,	O
choosing	O
which	O
goals	O
to	O
attempt	O
to	O
achieve	O
next	O
,	O
and	O
choosing	O
which	O
knowledge	O
area	O
to	O
apply	O
in	O
the	O
current	O
situation	O
.	O
</s>
<s>
Unlike	O
traditional	O
AI	B-Application
planning	I-Application
systems	O
that	O
generate	O
a	O
complete	O
plan	O
at	O
the	O
beginning	O
,	O
and	O
replan	O
if	O
unexpected	O
things	O
happen	O
,	O
PRS	O
interleaves	O
planning	O
and	O
doing	O
actions	O
in	O
the	O
world	O
.	O
</s>
<s>
PRS	O
is	O
based	O
on	O
the	O
BDI	O
or	O
belief	O
–	O
desire	O
–	O
intention	O
framework	O
for	O
intelligent	B-General_Concept
agents	I-General_Concept
.	O
</s>
<s>
Furthermore	O
,	O
each	O
of	O
these	O
three	O
components	O
is	O
typically	O
explicitly	O
represented	O
somewhere	O
within	O
the	O
memory	O
of	O
the	O
PRS	O
agent	O
at	O
runtime	O
,	O
which	O
is	O
in	O
contrast	O
to	O
purely	O
reactive	O
systems	O
,	O
such	O
as	O
the	O
subsumption	B-Architecture
architecture	I-Architecture
.	O
</s>
<s>
The	O
PRS	O
concept	O
was	O
developed	O
by	O
the	B-Application
Artificial	I-Application
Intelligence	I-Application
Center	O
at	O
SRI	O
International	O
during	O
the	O
1980s	O
,	O
by	O
many	O
workers	O
including	O
Michael	O
Georgeff	O
,	O
Amy	O
L	O
.	O
Lansky	O
,	O
and	O
François	O
Félix	O
Ingrand	O
.	O
</s>
<s>
Their	O
framework	O
was	O
responsible	O
for	O
exploiting	O
and	O
popularizing	O
the	O
BDI	O
model	O
in	O
software	O
for	O
control	O
of	O
an	O
intelligent	B-General_Concept
agent	I-General_Concept
.	O
</s>
<s>
Development	O
on	O
this	O
PRS	O
continued	O
at	O
the	O
Australian	O
Artificial	B-Application
Intelligence	I-Application
Institute	O
through	O
to	O
the	O
late	O
1990s	O
,	O
which	O
led	O
to	O
the	O
development	O
of	O
a	O
C++	B-Language
implementation	O
and	O
extension	O
called	O
dMARS	B-Application
.	O
</s>
<s>
Interpreter	B-Application
or	O
inference	O
mechanism	O
that	O
manages	O
the	O
system	O
.	O
</s>
<s>
As	O
such	O
it	O
specifically	O
addressed	O
the	O
limitations	O
of	O
other	O
contemporary	O
control	O
and	O
reasoning	O
architectures	O
like	O
expert	B-Application
systems	I-Application
and	O
the	O
blackboard	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
It	O
was	O
implemented	O
on	O
the	O
Symbolics	O
3600	O
Series	O
LISP	B-Language
machine	O
and	O
used	O
multiple	O
communicating	O
instances	O
of	O
PRS	O
.	O
</s>
