Let N R (x) represent the denominator of Equation (2), that is the normalization factor of R. We can rearrange Equation (2) as follows: where V D i,s represents the potential function of the s-th position of the sequence in the i-th CRF and V G j,s represents the probability of the s-th position in the j-th HMM, that is, xs , respectively.
to these previous studies, this paper proposes a semi-supervised SOL framework based on a hybrid generative and discriminative approach.