Keyphrases
- query performance prediction
- post retrieval
- query difficulty
- retrieval effectiveness
- query expansion
- microblog posts
- hot topics
- topic specific
- query suggestion
- relevance judgments
- average precision
- information retrieval systems
- information retrieval
- test collection
- retrieval model
- document retrieval
- topic models
- smoothing methods
- recent approaches
- web search
- probabilistic model
- image retrieval