Sharing knowledge between information extraction tasks has always been a challenge due to the diverse data formats and task variations. Meanwhile, this divergence leads to information waste and increases difficulties in building complex applications in real scenarios. Recent studies often formulate IE tasks as a triplet extraction problem. However, such a paradigm does not support multi-span and n-ary extraction, leading to weak versatility. To this end, we reorganize IE problems into unified multi-slot tuples and propose a universal framework for various IE tasks, namely Mirror. Specifically, we recast existing IE tasks as a multi-span cyclic graph extraction problem and devise a non-autoregressive graph decoding algorithm to extract all spans in a single step. It is worth noting that this graph structure is incredibly versatile, and it supports not only complex IE tasks, but also machine reading comprehension and classification tasks. We manually construct a corpus containing 57 datasets for model pretraining, and conduct experiments on 30 datasets across 8 downstream tasks. The experimental results demonstrate that our model has decent compatibility and outperforms or reaches competitive performance with SOTA systems under few-shot and zero-shot settings. The code, model weights, and pretraining corpus are available at https://github.com/Spico197/Mirror .

“事件要素抽取(Event Argument Extraction, EAE)旨在从非结构化文本中提取事件参与要素。编码器—解码器(Encoder-Decoder)框架是处理该任务的一种常见策略,此前的研究大多只向编码器端输入文本的字词信息,导致模型泛化和远程依赖处理能力较弱。为此,本文提出一种融入句法信息的事件要素抽取模型。首先对文本分析得到成分句法解析树,将词性标签和各节点的句法成分标签编码,增强模型的文本表征能力。然后,本文提出了一种基于树结构的注意力机制(Tree-Attention)辅助模型更好地感知结构化语义信息,提高模型处理远距离依赖的能力。实验结果表明,本文所提方法相较于基线系统F1值提升2.02%,证明该方法的有效性。”