The Importance of Automatic Syntactic Features in Vietnamese Named Entity Recognition
Table 5: Performance of our model when using one and two layers
['Entity', 'Two layers Pre.', 'Two layers Rec.', 'Two layers  [ITALIC] F1', 'One layer Pre.', 'One layer Rec.', 'One layer  [ITALIC] F1']
S4SS3SSS0Px3 Number of Bi-LSTM Layers In the third experiment, we investigate the improvement when adding more Bi-LSTM layers. We observe a significant improvement when using two layers of Bi-LSTM. The performance is increased from 71.74% to 74.02%