LX-DepParser's documentation

LX-DepParser

LX-DepParser is a free online service for the syntactic analysis of Portuguese. It allows the automatic parsing of sentences in Portuguese in terms of the grammatical functions of their words.

This service was developed and is maintained at the University of Lisbon by the NLX-Speech and Natural Language Group, Department of Informatics.

Parser

LX-DepParser is a MSTParser trained with Portuguese data.

For the training of the parser, 22,118 sentences were used (comprising 250,056 word tokens). The sentences were taken from the CINTIL-DependencyBank. This treebank is being developed and maintained at the University of Lisbon by the NLX-Speech and Natural Language Group of the Department of Informatics. In terms of evaluation, LX-DepParser's UAS (unlabeled attachment score) is 94.42 and its LAS (labeled attachment score) is 91.23. Scores were obtained through 10-fold cross-validation.

Consequently, the parser output complies with the design options adopted for the construction of the CINTIL-DependencyBank (see "Annotation Guidelines" below). The output of the parser can be obtained also in the format of Google's so-called Universal Dependencies, which results from the conversion of the original CINTIL output format by means of a set of regular expression rules over dependency trees, from which some residual distortion cases may happen to be introduced.

Tagset

Gramatical function tagset

Part-of-speech tags (high granularity)

Inflection tags

Annotation guidelines

The analyses produced by LX-DepParser are similar to the dependency representations found in the CINTIL-DependencyBank on which LX-DepParser was trained. This dependency treebank was designed along the principles described in the following handbook:

• Branco António, Sérgio Castro, João Silva, Francisco Costa, 2011, CINTIL DepBank Handbook: Design options for the representation of grammatical dependencies. Department of Informatics, University of Lisbon, Technical Reports series, nb. di-fcul-tr-11-03.

Authorship

LX-DepParser was developed by Rúben Reis, under the direction of António Branco at the NLX-Group on Natural Language and Speech.

Publications

Irrespective of the most recent version of this tool you may use, when mentioning it, please cite this reference:

• Branco António, Sérgio Castro, João Silva, Francisco Costa, 2011, CINTIL DepBank Handbook: Design options for the representation of grammatical dependencies. Department of Informatics, University of Lisbon, Technical Reports series, nb. di-fcul-tr-11-03.

Contact us

You can contact us at the following email address: 'nlx' followed by '@' followed by 'di.fc.ul.pt'.

Acknowledgments

LX-DepParser was partially funded by FCT-Foundation for Science and Technology, under the contract FCT/PTDC/PLP/81157/2006 for the project SemanticShare.