NavyTime: Event and Time Ordering from Raw Text
Nathanael Chambers · 2013
This paper describes a complete event/time ordering system that annotates raw text with events, times, and the ordering relations be-tween them at the SemEval-2013 Task 1. Task 1 is a unique challenge because it starts from raw text, rather than pre-annotated text with known events and times. A working system first identifies events and times, then identifies which events and times should be ordered, and finally labels the ordering relation between them. We present a split classifier approach that breaks the ordering tasks into smaller de-cision points. Experiments show that more specialized classifiers perform better than few joint classifiers. The NavyTime system ranked second both overall and in most subtasks like event extraction and relation labeling. 1