We measure the similarity between a class X (either O or T) and a cluster C i using the Jensen-Shannon divergence (JSD) (Lin, 1991) on the respective probability distributions.
we define the distance between the language models as the square root of the divergence value, which is a metric, often referred to as Jensen-Shannon distance (Endres and Schindelin, 2003): The assignment of the label X to the cluster C 1 is then supported by both C 1 's proximity to the class X and C 2 's proximity to the other class: C 2 is assigned the complementary label.