Relevance feedback using query-logs Gaurav Pandey Supervisors: Prof. Gerhard Weikum Julia...
-
Upload
milo-eaton -
Category
Documents
-
view
229 -
download
3
Transcript of Relevance feedback using query-logs Gaurav Pandey Supervisors: Prof. Gerhard Weikum Julia...
Relevance feedback using query-logs
Gaurav Pandey
Supervisors:Prof. Gerhard Weikum
Julia Luxenburger
Motivation
Results
Search Engine
Query
“One size fits all”
Motivation
Results
Search Engine
User infoQuery
Motivation
Python
Motivation
PythonCGI code Debugging programming
Usage of Query Logs
Clickthrough data
•Past queries
• Documents clicked
Usage of Query Logs
Query
Clicked Documents
History Instance
Query Reformulation
Result Query: “python information CGI code examples program code debugging bug removal programming”
But,
p(python/query)=? p(CGI)/query)=? p(code)/query)=?
…………………………..
Language ModelNormally(without using history), w:term
d: document q:query
Importance of term w in current query
Considers only the current query
But, not history instances
Language ModelNormally(without using history), w:term
d: document q:query
Importance of term w in current query
Now, using history:
Importance of term w in current query + history instances
?
Language Model+History
Importance of the term w at one instance in the history
Importance of term w in history instances
History query: “CGI code”
Documents: “CGI examples”,
“program code”
History query: “CGI code”
Documents: “CGI examples”, “program
code”
Equal Weighting
Works,but can be improved
Discriminative Weighting
Choose different for every history instance.. How?
Overlap
if a history query has common terms with the current query then
λi= 1,
Else if there is no common term
λi=0
Example:
Current query “python information”
History query:”python code” λi= 1
History query:”world cup” λi= 0
Soft overlap
if a history query has common terms with the current query then
λi= a,
Else if there is no common term
λi=b (a>b)
Example:
Current query “python information”
History query:”python code” λi= 8
History query:”world cup” λi= 2
Decrease with time
Use uniformly decreasing values
If there are n history instances,1 =n2 =n-13 =n-2……n-1 =2n =1
Decrease with time
Use geometrically decreasing values
If there are n history instances,1 =n2 =n/23 =n/3……n-1 =n/(n-1)n =1
Experiment Comparison of the 4 techniques Equal weighting Basic model (without history) Use similar techniques for: Probabilistic model Vector space model
Thanks