Mehdi Yousfi-Monod
Contact: mehdi.yousfi *at* gmail *dot* com

Ph.D Thesis

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Title (translated from French)

Automatic or semi-automatic text compression through removable constituent pruning: an interactive and corpus-free approach


This research belongs to the Natural Language Processing field and more specifically focuses on text summarization. The originality of this thesis leads in tackling a type of summarization that has not been studied much, text compression using an unsupervised method. This work presents an interactive and incremental system for syntagmatic tree pruning, while preserving the syntactic coherence and the main informational contents. On the theoretical side, this work is based on the Government and Biding theory of Noam Chomsky and more precisely on the formal representation of the X-bar theory, to aims at a strong foundation for a computational model compatible with syntactic compression of sentences. This work led to an operational software, currently working exclusively on French texts and named CoLin, which proposes two modalities: an automated compression and an assistance to summarization in a semi-automated form, directed through a tight interaction with the user. This software has been evaluated thanks to a quite complex protocol using 25 volunteers. Experiment results show that 1) the notion of reference abstract which is the basic of classical evaluation is at least questionable, 2) semi-automated compression has been given a high value by users 3) fully automated compressions also get honourable satisfaction levels. With a compression ratio of over 40% for all genres of text, CoLin offers an appreciable support as an assistance to text compression, without resorting on a learning corpus, and with a user-friendly interface.


NLP; automatic summarization; semi-automatic summarization; sentence compression; government and binding theory; syntactic tree; constituent grammar; interactive tool


Jacques CHAUCHÉProfessor, University of Montpellier 2Chairman
Jacques VERGNEProfesseur, University of CaenExaminer
Jean-Luc MINELResearch Engineer, University of Paris 10Examiner
Juan Manuel TORRES-MORENOProfessor Assistant, University of AvignonReviewer
Augusta MELAProfessor Assistant, University of Montpellier 3Reviewer
Violaine PRINCEProfesseur, University of Montpellier 2PhD Advisor