On top of that, specific shared framework use both a shared NN and domain-specific NNs to derive shared and domain-specific features (Ganin et al., 2016;Taigman et al., 2017;Yu et al., 2018).
it may not be ideal to separate shared and specific features, recent studies (Ganin et al., 2016;Taigman et al., 2017;Liu et al., 2017b) consider the adversarial networks to learn more robust shared features across domains.