Keyphrases
- negative matrix factorization
- document clustering
- nonnegative matrix factorization
- latent semantic space
- text summarization
- principal component analysis
- document representation
- document collections
- matrix factorization
- constrained least squares
- text documents
- information retrieval
- vector space model
- information retrieval systems
- text mining
- web documents
- document retrieval
- clustering algorithm
- sparse representation
- collaborative filtering
- keywords
- question answering
- input data
- knowledge base