Self-Attention Guided Copy Mechanism for Abstractive Summarization
Song Xu, Haoran Li, Peng Yuan, Youzheng Wu, Xiaodong He, Bowen Zhou · 2020
Copy module has been widely equipped in the recent abstractive summarization models, which facilitates the decoder to extract words from the source into the summary.Generally, the encoder-decoder attention is served as the copy distribution, while how to guarantee that important words in the source are copied remains a challenge.In this work, we propose a Transformer-based model to enhance the copy mechanism.Specifically, we identify the importance of each source word based on the degree centrality with a directed graph built by the self-attention layer in the Transformer.We use the centrality of each source word to guide the copy process explicitly.Experimental results show that the self-attention graph provides useful guidance for the copy distribution.Our proposed models significantly outperform the baseline methods on the CNN/Daily Mail dataset and the Gigaword dataset.