Token-Event-Role Structure-based Multi-Channel Document-Level Event Extraction

TL;DR

This paper presents a novel token-event-role data structure and multi-channel prediction module for document-level event extraction, improving performance and efficiency by modeling token roles across multiple events.

Contribution

It introduces a new data structure and a unified prediction framework that better captures cross-event entity correlations, outperforming existing methods.

Findings

Outperforms state-of-the-art by 9.5 F1 points

Reduces model complexity and parameter size

Ablation study confirms the effectiveness of the data structure

Abstract

Document-level event extraction is a long-standing challenging information retrieval problem involving a sequence of sub-tasks: entity extraction, event type judgment, and event type-specific multi-event extraction. However, addressing the problem as multiple learning tasks leads to increased model complexity. Also, existing methods insufficiently utilize the correlation of entities crossing different events, resulting in limited event extraction performance. This paper introduces a novel framework for document-level event extraction, incorporating a new data structure called token-event-role and a multi-channel argument role prediction module. The proposed data structure enables our model to uncover the primary role of tokens in multiple events, facilitating a more comprehensive understanding of event relationships. By leveraging the multi-channel prediction module, we transform entity and multi-event extraction into a single task of predicting token-event pairs, thereby reducing the overall parameter size and enhancing model efficiency. The results demonstrate that our approach outperforms the state-of-the-art method by 9.5 percentage points in terms of the F1 score, highlighting its superior performance in event extraction. Furthermore, an ablation study confirms the significant value of the proposed data structure in improving event extraction tasks, further validating its importance in enhancing the overall performance of the framework.