Evaluating Centering for Information Ordering Using Corpora

In this article we discuss several metrics of coherence defined using centering theory and investigate the usefulness of such metrics for information ordering in automatic text generation. We estimate empirically which is the most promising metric and how useful this metric is using a general methodology applied on several corpora. Our main result is that the simplest metric (which relies exclusively on NOCB transitions) sets a robust baseline that cannot be outperformed by other metrics which make use of additional centering-based features. This baseline can be used for the development of both text-to-text and concept-to-text generation systems. </jats:p

Generating plural NPs in discourse : evidence from the GNOME corpus

Research on the automatic generation of referring expressions has extended algorithms for the generation of full definite NPs to deal with anaphoric references. However, there has been relatively little work on the specific problems raised by plural anaphora. In particular, since plurals involve a reference to a set rather than an individual, one of the interesting questions concerns the extent to which elements of the set introduced by a plurality are salient, as compared to the plurality itself. This paper offers a preliminary exploration of these questions through a study of a small, richly annotated corpus. We discuss the implications of some of the findings for automatic referring expression generation, and also identify some fruitful avenues for future work.peer-reviewe