The log-likelihood of the whole data set D in Equation (1) can be defined as follows: Replacing P (w,d,r) by the values computed using the bridged model in Equation 2results in: The above optimization problems are hard to compute due to the log of sum.
-0.4-0.5) value for sentiment orientation (Neviarouskaya et al., 2007;Neviarouskaya et al., 2009).