<s>
Stochastic	O
Approach	O
for	O
Link-Structure	O
Analysis	O
(	O
SALSA	O
)	O
is	O
a	O
web	O
page	B-Algorithm
ranking	I-Algorithm
algorithm	O
designed	O
by	O
R	O
.	O
Lempel	O
and	O
S	O
.	O
Moran	O
to	O
assign	O
high	O
scores	O
to	O
hub	O
and	O
authority	O
web	O
pages	O
based	O
on	O
the	O
quantity	O
of	O
hyperlinks	O
among	O
them	O
.	O
</s>
<s>
SALSA	O
is	O
inspired	O
by	O
two	O
other	O
link-based	O
ranking	O
algorithms	O
,	O
namely	O
HITS	B-Application
and	O
PageRank	B-Algorithm
,	O
in	O
the	O
following	O
ways	O
:	O
</s>
<s>
like	O
HITS	B-Application
,	O
the	O
algorithm	O
assigns	O
two	O
scores	O
to	O
each	O
web	O
page	O
:	O
a	O
hub	O
score	O
and	O
an	O
authority	O
score	O
.	O
</s>
<s>
like	O
HITS	B-Application
,	O
SALSA	O
also	O
works	O
on	O
a	O
focused	O
subgraph	O
which	O
is	O
topic-dependent	O
.	O
</s>
<s>
like	O
PageRank	B-Algorithm
,	O
the	O
algorithm	O
computes	O
the	O
scores	O
by	O
simulating	O
a	O
random	O
walk	O
through	O
a	O
Markov	O
chain	O
that	O
represents	O
the	O
graph	O
of	O
web	O
pages	O
.	O
</s>
<s>
This	O
is	O
a	O
departure	O
from	O
HITS	B-Application
's	O
notions	O
of	O
hubs	B-Application
and	I-Application
authorities	I-Application
based	O
on	O
a	O
mutually	O
reinforcing	O
relationship	O
.	O
</s>
<s>
SALSA	O
can	O
be	O
seen	O
as	O
an	O
improvement	O
of	O
HITS	B-Application
.	O
</s>
<s>
The	O
computational	O
cost	O
of	O
the	O
algorithm	O
is	O
a	O
crucial	O
factor	O
since	O
HITS	B-Application
and	O
SALSA	O
are	O
computed	O
at	O
query	O
time	O
and	O
can	O
therefore	O
significantly	O
affect	O
the	O
response	O
time	O
of	O
a	O
search	O
engine	O
.	O
</s>
<s>
This	O
should	O
be	O
contrasted	O
with	O
query-independent	O
algorithms	O
like	O
PageRank	B-Algorithm
that	O
can	O
be	O
computed	O
off-line	O
.	O
</s>
<s>
SALSA	O
is	O
less	O
vulnerable	O
to	O
the	O
Tightly	O
Knit	O
Community	O
(	O
TKC	O
)	O
effect	O
than	O
HITS	B-Application
.	O
</s>
<s>
The	O
presence	O
of	O
TKCs	O
in	O
a	O
focused	O
subgraph	O
is	O
known	O
to	O
negatively	O
affect	O
the	O
detection	O
of	O
meaningful	O
authorities	O
by	O
HITS	B-Application
.	O
</s>
<s>
The	O
Twitter	B-Application
Social	O
network	O
uses	O
a	O
SALSA	O
style	O
algorithm	O
to	O
suggest	O
accounts	O
to	O
follow	O
.	O
</s>
