<s>
Rank	B-General_Concept
SIFT	I-General_Concept
algorithm	O
is	O
the	O
revised	O
SIFT	O
(	O
Scale-invariant	B-Algorithm
feature	I-Algorithm
transform	I-Algorithm
)	O
algorithm	O
which	O
uses	O
ranking	O
techniques	O
to	O
improve	O
the	O
performance	O
of	O
the	O
SIFT	O
algorithm	O
.	O
</s>
<s>
Then	O
the	O
vector	O
set	O
containing	O
labeled	O
elements	O
can	O
be	O
used	O
as	O
a	O
training	O
set	O
for	O
the	O
Ranking	B-Algorithm
SVM	I-Algorithm
problem	O
.	O
</s>
<s>
The	O
Spearman	B-General_Concept
correlation	I-General_Concept
coefficient	O
also	O
refers	O
to	O
Spearman	B-General_Concept
's	I-General_Concept
rank	I-General_Concept
correlation	I-General_Concept
coefficient	I-General_Concept
.	O
</s>
<s>
The	O
Kendall	B-General_Concept
's	I-General_Concept
Tau	I-General_Concept
also	O
refers	O
to	O
Kendall	B-General_Concept
tau	I-General_Concept
rank	I-General_Concept
correlation	I-General_Concept
coefficient	I-General_Concept
.	O
</s>
