Recognition and normalisation of temporal expressions using conditional random fields and cascade of partial rules

This article introduces the issue of recognition and normalisation of temporal expressions for the Polish language. We describe what temporal information is and we present TimeML specification, adapted to Polish as a model for the description of temporal expressions. Classes of temporal expressions are presented as well as guidelines for annotation, normalisation of these expressions and our approach to corpus annotation and temporal expressions recognition. The key aspect of the work is the description of the features used for the recognition, the use of the method for selection and creation of feature templates for the model of Conditional Random Fields. We demonstrate the experiments and conclusions drawn from them.