In this paper, we describe HeidelTime, a system for the extraction and normalization of temporal expressions. HeidelTime is a rule-based system mainly using regular expression patterns for the extraction of temporal expressions and knowledge resources as well as linguistic clues for their normalization. In the TempEval-2 challenge, HeidelTime achieved the highest FScore (86%) for the extraction and the best results in assigning the correct value attribute, i.e., in understanding the semantics of the temporal expressions.
For English language in the context of TempEval-2, HeidelTime REF gained the best F1 score of 0.86 by introducing a rule based system, which used regular expressions for extracting time expression and knowledge resources as well as linguistic clues for their normalization.
HeidelTime: High Quality Rule-Based Extraction and Normalization of Temporal Expressions
Workshop on Semantic Evaluations (SemEval)
Computer Science