Multi-Task Learning for Boosting with Application to Web Search Ranking Olivier Chapelle et al....
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Transcript of Multi-Task Learning for Boosting with Application to Web Search Ranking Olivier Chapelle et al....
Multi-Task Learning for Boosting with Application to Web Search Ranking
Olivier Chapelle et al.
Presenter: Wei Cheng
Outline
• Motivation• Backgrounds• Algorithm– From svm to boosting using L1 regularization– Є-boosting for optimization– Overall algorithm
• Evaluation• Overall review and new research points
discussion
Motivation
Different/same search engine(s) for different
countries?
Domain specific engine is better!e.g. ‘gelivable’ (very useful)
Motivation
• Should we train ranking model separately?– Corps in some domains might be too small to train
a good model– Solution:
Multi-task learning
Algorithm
• The algorithm aims at designing an algorithm based on gradient boosted decision trees
• Inspired by svm based multi-task solution and boosting-trick.
• Using Є-boosting for optimization
Algorithm
• Svm(kernel-trick)---boosting (boosting trick)
Pick set of non-linear functions(e.g., decision trees,
regression trees,….)
H|H|=J
Apply every single function to each data point
1( )
.( )
.
( )J
h x
x
h x
Xф(X)
Overall review and new research point discussion
• Contributions:– Propose a novel multi-task learning method based
on gradient boosted decision tree, which is useful for web-reranking applications. (e.g., personalized search).
– Have a thorough evaluation on we-scale datasets.• New research points:– Negative transfer:– Effective grouping: flexible domain adaptation