EventGraph at CASE 2021 Task 1: A General Graph-based Approach to Protest Event Extraction
This work addresses protest event extraction for multilingual text analysis, but it is incremental as it applies an existing graph-based method to a specific shared task.
The paper tackled protest event extraction by adapting a graph-based semantic parser, specifically testing labeled-edge and node-centric graphs, with the node-centric approach achieving best results, ranking 3rd for English and Portuguese and 4th for Spanish in the CASE 2021 shared task.
This paper presents our submission to the 2022 edition of the CASE 2021 shared task 1, subtask 4. The EventGraph system adapts an end-to-end, graph-based semantic parser to the task of Protest Event Extraction and more specifically subtask 4 on event trigger and argument extraction. We experiment with various graphs, encoding the events as either "labeled-edge" or "node-centric" graphs. We show that the "node-centric" approach yields best results overall, performing well across the three languages of the task, namely English, Spanish, and Portuguese. EventGraph is ranked 3rd for English and Portuguese, and 4th for Spanish. Our code is available at: https://github.com/huiling-y/eventgraph_at_case