Document Level Time-Anchoring For Timeline Extraction

This paper investigates the contribution of document level processing of time-anchors for TimeLine event extraction. We developed and tested two different systems. The first one is a baseline system that captures explicit time-anchors. The second one extends the baseline system by also capturing implicit time relations. We have evaluated both approaches in the SemEval 2015 task 4 TimeLine: Cross-Document Event Ordering. We empirically demonstrate that the document-based approach obtains a much more complete time anchoring. Moreover, this approach almost doubles the performance of the systems that participated in the task.