Encoding Sentences with Graph Convolutional Networks for Semantic Role Labeling
Diego Marcheggiani, Ivan S. Titov · 2017
Semantic role labeling (SRL) is the task of identifying the predicate-argument structure of a sentence.It is typically regarded as an important step in the standard NLP pipeline.As the semantic representations are closely related to syntactic ones, we exploit syntactic information in our model.We propose a version of graph convolutional networks (GCNs), a recent class of neural networks operating on graphs, suited to model syntactic dependency graphs.GCNs over syntactic dependency trees are used as sentence encoders, producing latent feature representations of words in a sentence.We observe that GCN layers are complementary to LSTM ones: when we stack both GCN and LSTM layers, we obtain a substantial improvement over an already state-of-theart LSTM SRL model, resulting in the best reported scores on the standard benchmark (CoNLL-2009) both for Chinese and English.