Question: What are the baseline methods?
Answer: (1) Naive, (2) mSDA BIBREF7, (3) NaiveNN, (4) AuxNN BIBREF4, (5) ADAN BIBREF16, (6) MMD
Alternative answer: non-domain-adaptive baseline with bag-of-words representations and SVM classifier, mSDA, non-domain-adaptive CNN trained on source domain, neural model that exploits auxiliary tasks, adversarial training to reduce representation difference between domains, variants of deep CNNs are used for encoding images and the MMDs of multiple layers are jointly minimized