Merging PropBank, NomBank, TimeBank, Penn Discourse Treebank and Coreference

Proceedings of the Workshop on Frontiers in Corpus Annotation II: Pie in the Sky, pages 5–12, Ann Arbor, June 2005. c⃝2005 Association for Computational Linguistics Merging PropBank, NomBank, TimeBank, Penn Discourse Treebank and Coreference James Pustejovsky, Adam Meyers, Martha Palmer, Massimo Poesio Abstract Many recent annotation efforts for English have focused on pieces of the larger problem of semantic annotation, rather than initially producing a single unified representation. This paper discusses the issues involved in merging four of these efforts into a unified linguistic structure: PropBank, NomBank, the Discourse Treebank and Coreference Annotation undertaken at the University of Essex. We discuss resolving overlapping and conflicting annotation as well as how the various annotation schemes can reinforce each other to produce a representation that is greater than the sum of its parts. 1. Introduction The creation of the Penn Treebank (Marcus et al, 1993) and the word sense-annotated SEMCOR (Fellbaum, 1997) have shown how even limited amounts of annotated data can result in major improvements in complex natural language understanding systems. These annotated corpora have led to high-level improvements for parsing and word sense disambiguation (WSD), on the same scale as previously occurred for Part of Speech tagging by the annotation of the Brown corpus and, more recently, the British National Corpus (BNC) (Burnard, 2000). However, the creation of semantically annotated corpora has lagged dramatically behind the creation of other linguistic resources: in part due to the perceived cost, in part due to an assumed lack of theoretical agreement on basic semantic judgments, in part, finally, due to the understandable unwillingness of research groups to get involved in such an undertaking. As a result, the need for such resources has become urgent. Many recent annotation efforts for English have focused on pieces of the larger problem of semantic annotation, rather than producing a single unified representation like Head-driven Phrase Structure Grammar (Pollard and Sag 1994) or the Prague Dependency Tecto- gramatical Representation (Hajicova & Kucer- ova, 2002). PropBank (Palmer et al, 2005) annotates predicate argument structure anchored by verbs. NomBank (Meyers, et. al., 2004a) annotates predicate argument structure anchored by nouns. TimeBank (Pustejovsky et al, 2003) annotates the temporal features of propositions and the temporal relations between propositions. The Penn Discourse Treebank (Miltsakaki et al 2004a/b) treats discourse connectives as predicates and the sentences being joined as arguments. Researchers at Essex were responsible for the coreference markup scheme developed in MATE (Poesio et al, 1999; Poesio, 2004a) and have annotated corpora using this scheme including a subset of the Penn Treebank (Poesio and Vieira, 1998), and the GNOME corpus (Poesio, 2004a). This paper discusses the issues involved in creating a Unified Linguistic Annotation (ULA) by merging annotation of examples using the schemata from these efforts. Crucially, all individual annotations can be kept separate in order to make it easy to produce alternative annotations of a specific type of semantic information without need to modify the annotation at the other levels. Embarking on separate annotation efforts has the advantage of allowing researchers …

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