Document-Level Multi-Event Extraction with Event Proxy Nodes and Hausdorff Distance Minimization

Document-level multi-event extraction aims to extract the structural information from a given document automatically. Most recent approaches usually involve two steps: (1) modeling entity interactions; (2) decoding entity interactions into events. However, such approaches ignore a global view of inter-dependency of multiple events. Moreover, an event is decoded by iteratively merging its related entities as arguments, which might suffer from error propagation and is computationally inefficient. In this paper, we propose an alternative approach for document-level multi-event extraction with event proxy nodes and Hausdorff distance minimization. The event proxy nodes, representing pseudo-events, are able to build connections with other event proxy nodes, essentially capturing global information. The Hausdorff distance makes it possible to compare the similarity between the set of predicted events and the set of ground-truth events. By directly minimizing Hausdorff distance, the model is trained towards the global optimum directly, which improves performance and reduces training time. Experimental results show that our model outperforms previous state-of-the-art method in F1-score on two datasets with only a fraction of training time. 1 1 Code is available at https://github.com/xnyuwg/procnet ... [5] Shenkai Petrochemical Co., Ltd. received the receipt from the company's shareholder, Yexiang Investment Management Co., Ltd. on the evening of November 15, 2016 Regarding the notice of the shares being frozen. ... [8] On November 14, 2016, Yexiang Investment received the Notice of Litigation Preservation from the People's Court of Binjiang District, and granted a total of 47,577,481 shares held by Yexiang Investment will be frozen, and the freezing period is from October 31, 2016 to October 30, 2019 ... [10] Yexiang Investment is … holding 47,577,481 shares of the company, accounting for 13.07% of the company's total share capital. ... [12] On February 2, 2016, the 42,000,000 shares held by it are pledged to Haitong Securities Co., Ltd., and the repurchase transaction date was February 1, 2017. ...