Many other studies (Titov and McDonald, 2008;Wang et al., 2010;Wang et al., 2011;Diao et al., 2014;Pappas and Popescu-Belis, 2014;Pontiki et al., 2016;Toh and Su, 2016) solve multiaspect sentiment classification as a subproblem by utilizing heuristic based methods or topic models.
these approaches often rely on strict assumptions about words and sentences, for example, word syntax has been used to distinguish aspect word or sentiment word, or appending an specific aspect to a sentence.