where Q P (j) ,P e Â Ã Q 0 J s P (j) ,P e Â Ã , Q 0 is a normalization factor, and J s P (1) ,P (2) Â Ã is the Jensen-Shannon's divergence between two probability density functions P (1) and P (2) , which in turn is defined as J s P (1) ,P (2) Â Ã H P (1) zP (2) 2