<s>
Beam	B-Algorithm
stack	I-Algorithm
search	I-Algorithm
is	O
a	O
search	B-Application
algorithm	I-Application
that	O
combines	O
chronological	O
backtracking	B-Algorithm
(	O
that	O
is	O
,	O
depth-first	B-Algorithm
search	I-Algorithm
)	O
with	O
beam	B-Algorithm
search	I-Algorithm
and	O
is	O
similar	O
to	O
depth-first	B-Algorithm
beam	B-Algorithm
search	I-Algorithm
.	O
</s>
<s>
Both	O
search	B-Application
algorithms	I-Application
are	O
anytime	B-Algorithm
algorithms	I-Algorithm
that	O
find	O
good	O
but	O
likely	O
sub-optimal	O
solutions	O
quickly	O
,	O
like	O
beam	B-Algorithm
search	I-Algorithm
,	O
then	O
backtrack	O
and	O
continue	O
to	O
find	O
improved	O
solutions	O
until	O
convergence	O
to	O
an	O
optimal	O
solution	O
.	O
</s>
<s>
Beam	B-Algorithm
stack	I-Algorithm
search	I-Algorithm
uses	O
the	O
beam	B-Algorithm
stack	I-Algorithm
as	O
a	O
data	B-General_Concept
structure	I-General_Concept
to	O
integrate	O
chronological	O
backtracking	B-Algorithm
with	O
beam	B-Algorithm
search	I-Algorithm
and	O
can	O
be	O
combined	O
with	O
the	O
divide	B-Algorithm
and	I-Algorithm
conquer	I-Algorithm
algorithm	I-Algorithm
technique	O
,	O
resulting	O
in	O
divide-and-conquer	O
beam-stack	O
search	O
.	O
</s>
<s>
Beam	B-Algorithm
search	I-Algorithm
using	O
limited	O
discrepancy	O
backtracking	B-Algorithm
(	O
BULB	O
)	O
is	O
a	O
search	B-Application
algorithm	I-Application
that	O
combines	O
limited	O
discrepancy	O
search	O
with	O
beam	B-Algorithm
search	I-Algorithm
and	O
thus	O
performs	O
non-chronological	O
backtracking	B-Algorithm
,	O
which	O
often	O
outperforms	O
the	O
chronological	O
backtracking	B-Algorithm
done	O
by	O
beam	B-Algorithm
stack	I-Algorithm
search	I-Algorithm
and	O
depth-first	B-Algorithm
beam	B-Algorithm
search	I-Algorithm
.	O
</s>
