SUTIME: A Library for Recognizing and Normalizing Time Expressions

Paper Link

Detecting Temporal Expressions

There are 2 steps for extracting time from natural language expressions -

1. Detecting temporal expressions.
2. Extracting normalized time expressions from natural language phrases.

This paper is about the latter. They use TIMEX representation of time expression.

Types of Temporal Expressions

There are 4 types of temporal expressions -

1. Time - A time point indicating a particular instance on a time scale. Examples include Nov 20 1988, 5:30 PM, now, next weekend or Sunday Evening.

2. Duration - The amount of intervening time between the two end-points of a time interval. Examples include 5 days, 10 months, a decade, few years or 2-3 months.

3. Interval - A range of time defined by a start and end time points. Examples include Jan 2021 to Feb 2022.

4. Set - A set of temporals. Examples include “every 3rd Sunday”.

Datasets and Evaluation

• A popular dataset is TempEval-2. SUTime had the best Recall and F1 on this dataset but HeidelTime had the best precision. They’ve incorporated the work into Stanford CoreNLP.

Kaushik Rangadurai

Code. Learn. Explore

Share this post