Dependency or Span, End-to-End Uniform Semantic Role Labeling
Table 6: Effectiveness of ELMo representations and biaffine scorer on the CoNLL 2005 and 2008 WSJ sets.
['System', 'CoNLL-2005', 'CoNLL-2008']
We observe that effect of ELMo is somewhat surprising, where removal of the ELMo dramatically declines the performance by 3.3-3.5 F1 on CoNLL-2005 WSJ. However, our model gives quite stable performance for dependency SRL regardless of whether ELMo is concatenated or not. The results indicate that ELMo is more beneficial to span SRL. In order to better understand how the biaffine scorer influences our model performance, we train our model with different scoring functions. We can see 0.5% and 1.6% F1 performance degradation on CoNLL 2005 and 2008 WSJ respectively. The comparison shows that the biaffine scorer is more effective for scoring the relations between predicates and arguments. Furthermore, these results show that biaffine attention mechanism is applicable to span SRL.