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2012 Apr 01
1
[GSoC2012] Learning to Rank: few thoughts/issues
...here and researching a bit
about the issues myself. I wanted to discuss about a few issues/thoughts:
*Doubt1:*
*Feature Extraction/Selection:*
The various datasets listed on MSR's LETOR have a limited set of features.
Current implementation in xapian's LETOR has 5
features[tf,idf,doc_len,coll_tf,coll_len]. While algorithms for learning
ranking models have been intensively studied, this is not the case for
feature selection, despite of its importance. In a paper presented at
SIGIR'07 [Tier1 in IR domain], the authors have highlighted the
effectiveness of feature selection methods for ra...
2011 Jun 07
0
Introduction and Discussion for Learning to Rank Framework
...[methods] of the
Xapian::Letor class and then will explain the whole flow of the 'Letor'
ranking.
Structure of the Xapian::Letor class
methods:
Following Five methods basically prepare the statistical information needed
to generate the values of desired features.
tf()
idf()
doc_len()
coll_tf()
coll_len()
Following six methods will calucate the particular feature values with the
help of above statistical information. Here char ch plays a roll to tell the
method that this features value is to be calculated for which documents
part. For example [ ch = 't' says calculate feature...