# Web Science/Part2: Emerging Web Properties/Modelling Similarity of Text/Probabilistic Similarity Measures Kullback Leibler Divergence

# Probabilistic Similarity Measures Kullback Leibler Divergence

- Be aware of a unigram Language Model
- Know Laplacian (aka +1) smoothing
- Know the query likelihood model
- The Kullback Leibler Divergence
- See how a similarity measure can be derived from Kullback Leibler Divergence

The slides can be found at File:Probabilistic-Similarity-Measures-Kullback-Leibler-Divergence.pdf