Preamble
PAULA XML or PAULA for short (Potsdamer AUstauschformat Linguistischer Annotationen, 'Potsdam Exchange Format for Linguistic Annotations') is a standoff XML format designed to represent a wide range of linguistically annotated textual and multi-modal corpora. The format was created at Potsdam University and developed within SFB 632, the collaborative research centre "Information Structure", subproject D1, "Linguistic Database" at Potsdam University and Humboldt-Universität zu Berlin (see Dipper 20051, Dipper and Goetze 20052, Chiarcos et al. 20083). The description below represents the normative documentation for PAULA version 1.1, with some notes on previous versions of PAULA. For the latest documentation always check the PAULA Website which also contains an online HTML version of this documentation.
The standoff nature of PAULA refers to the fact that each layer of linguistic annotation, such as part-of-speech annotations, lemmatizations, syntax trees, coreference annotation etc. are stored in separate XML files which refer to the same raw data. In this manner annotations can easily be added, deleted and updated without disturbing independent annotation layers, and discontinuous or hierarchically conflicting structures can be represented. Additionally the format ensures the retainment of unaltered raw data, including white space and other elements often lost due to restrictions of the encoding format. As a generalized XML format, PAULA is indifferent to particular names or semantics of annotation structures. It concentrates instead on the representation of corpus data as a set of arbitrarily labeled directed acyclic graphs (so called multi-DAGs, wherein annotation projects may contain cycles as long as these are on different annotation levels).
This documentation is structured as follows: the next chapter gives an overview of the overall data model of the current PAULA format, followed by a chapter on corpus structure for XML files and folders. Further chapters review different file types: the minimal necessary files for PAULA documents, metadata, primary text data, tokenizations and span annotations, hierarchical graphs and pointing relations. The final chapters give additional information on the optional use of namespaces, some special scenarios such as building parallel corpora, dialogue corpora and multimodal corpora, recommendations for file naming conventions and information on older/deprecated elements of the PAULA XML standard focusing on differences to the current version.
Dipper, S. (2005), XML-based Stand-off Representation and Exploitation of Multi-Level Linguistic Annotation. In: Proceedings of Berliner XML Tage 2005 (BXML 2005). Berlin, Germany, 39-50.
Dipper, S. & Götze, M. (2005), Accessing Heterogeneous Linguistic Data - Generic XML-based Representation and Flexible Visualization . In: Proceedings of the 2nd Language & Technology Conference: Human Language Technologies as a Challenge for Computer Science and Linguistics. Poznan, Poland, 206-210.
Chiarcos, C., Dipper, S., Götze, M., Leser, U., Lüdeling, A., Ritz, J. & Stede, M. (2008), A Flexible Framework for Integrating Annotations from Different Tools and Tag Sets. Traitment automatique des langues 49, 271-293.