Keyphrases
- constrained least squares
- regularized least squares
- regularization parameter
- negative matrix factorization
- higher order
- basis vectors
- nonnegative matrix factorization
- image restoration
- least squares
- dimensionality reduction
- special case
- linear combination
- sparse representation
- document collections
- feature selection
- unsupervised learning
- pairwise
- objective function
- image processing