Before revision:  In our work, we (1) propose modelling the hierarchical structure between dialogue policy and natural language generator (NLG) with the option framework, called HDNO  ;
After revision:  In our work, we (1) propose modelling the hierarchical structure between dialogue policy and natural language generator (NLG) with the option framework, called HDNO , where the latent dialogue act is applied to avoid designing specific dialogue act representations ;