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Computación y Sistemas

Print version ISSN 1405-5546

Comp. y Sist. vol.18 n.3 México Jul./Sep. 2014 

Artículos regulares


Paraphrase and Textual Entailment Generation in Czech


Zuzana Nevěřilová


Natural Language Processing Centre, Faculty of Informatics, Masaryk University, Brno, Czech Republic.


Article received on 07/01/2014.
Accepted on 01/02/2014.



Paraphrase and textual entailment generation can support natural language processing (NLP) tasks that simulate text understanding, e.g., text summarization, plagiarism detection, or question answering. A paraphrase, i.e., a sentence with the same meaning, conveys a certain piece of information with new words and new syntactic structures. Textual entailment, i.e., an inference that humans will judge most likely true, can employ real-world knowledge in order to make some implicit information explicit. Paraphrases can also be seen as mutual entailments. We present a new system that generates paraphrases and textual entailments from a given text in the Czech language. First, the process is rule-based, i.e., the system analyzes the input text, produces its inner representation, transforms it according to transformation rules, and generates new sentences. Second, the generated sentences are ranked according to a statistical model and only the best ones are output. The decision whether a paraphrase or textual entailment is correct or not is left to humans. For this purpose we designed an annotation game based on a conversation between a detective (the human player) and his assistant (the system). The result of such annotation is a collection of annotated pairs text-hypothesis. Currently, the system and the game are intended to collect data in the Czech language. However, the idea can be applied for other languages. So far, we have collected 3,321 H-T pairs. From these pairs, 1,563 were judged correct (47.06 %), 1,238 (37.28 %) were judged incorrect entailments, and 520 (15.66 %) were judged non-sense or unknown.

Keywords: Games with a purpose, paraphrase, textual entailment, natural language generation.





This work has been partly supported by the Ministry of Education of CR within the LINDAT-Clarin project LM2010013 and by the Ministry of the Interior of CR within the project VF20102014003.

The access to computing and storage facilities owned by parties and projects contributing to the National Grid Infrastructure MetaCentrum, provided under the programme "Projects of Large Infrastructure for Research, Development, and Innovations" (LM2010005) is appreciated.



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