Maximin Coavoux


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BERT Is Not The Count: Learning to Match Mathematical Statements with Proofs
Weixian Waylon Li | Yftah Ziser | Maximin Coavoux | Shay B. Cohen
Proceedings of the 17th Conference of the European Chapter of the Association for Computational Linguistics

We introduce a task consisting in matching a proof to a given mathematical statement. The task fits well within current research on Mathematical Information Retrieval and, more generally, mathematical article analysis (Mathematical Sciences, 2014). We present a dataset for the task (the MATcH dataset) consisting of over 180k statement-proof pairs extracted from modern mathematical research articles. We find this dataset highly representative of our task, as it consists of relatively new findings useful to mathematicians. We propose a bilinear similarity model and two decoding methods to match statements to proofs effectively. While the first decoding method matches a proof to a statement without being aware of other statements or proofs, the second method treats the task as a global matching problem. Through a symbol replacement procedure, we analyze the “insights” that pre-trained language models have in such mathematical article analysis and show that while these models perform well on this task with the best performing mean reciprocal rank of 73.7, they follow a relatively shallow symbolic analysis and matching to achieve that performance.

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PROPICTO: Developing Speech-to-Pictograph Translation Systems to Enhance Communication Accessibility
Lucía Ormaechea | Pierrette Bouillon | Maximin Coavoux | Emmanuelle Esperança-Rodier | Johanna Gerlach | Jerôme Goulian | Benjamin Lecouteux | Cécile Macaire | Jonathan Mutal | Magali Norré | Adrien Pupier | Didier Schwab
Proceedings of the 24th Annual Conference of the European Association for Machine Translation

PROPICTO is a project funded by the French National Research Agency and the Swiss National Science Foundation, that aims at creating Speech-to-Pictograph translation systems, with a special focus on French as an input language. By developing such technologies, we intend to enhance communication access for non-French speaking patients and people with cognitive impairments.

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Pretrained Language Models v. Court Ruling Predictions: A Case Study on a Small Dataset of French Court of Appeal Rulings
Olivia Vaudaux | Caroline Bazzoli | Maximin Coavoux | Géraldine Vial | Étienne Vergès
Proceedings of the Natural Legal Language Processing Workshop 2023

NLP systems are increasingly used in the law domain, either by legal institutions or by the industry. As a result there is a pressing need to characterize their strengths and weaknesses and understand their inner workings. This article presents a case study on the task of judicial decision prediction, on a small dataset from French Courts of Appeal. Specifically, our dataset of around 1000 decisions is about the habitual place of residency of children from divorced parents. The task consists in predicting, from the facts and reasons of the documents, whether the court rules that children should live with their mother or their father. Instead of feeding the whole document to a classifier, we carefully construct the dataset to make sure that the input to the classifier does not contain any ‘spoilers’ (it is often the case in court rulings that information all along the document mentions the final decision). Our results are mostly negative: even classifiers based on French pretrained language models (Flaubert, JuriBERT) do not classify the decisions with a reasonable accuracy. However, they can extract the decision when it is part of the input. With regards to these results, we argue that there is a strong caveat when constructing legal NLP datasets automatically.

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Analyse sémantique AMR pour le français par transfert translingue
Jeongwoo Kang | Maximin Coavoux | Didier Schwab | Cédric Lopez
Actes de CORIA-TALN 2023. Actes de la 30e Conférence sur le Traitement Automatique des Langues Naturelles (TALN), volume 2 : travaux de recherche originaux -- articles courts

Abstract Meaning Representation (AMR) est un formalisme permettant de représenter la sémantique d’une phrase sous la forme d’un graphe, dont les nœuds sont des concepts sémantiques et les arcs des relations typées. Dans ce travail, nous construisons un analyseur AMR pour le français en étendant une méthode translingue zéro-ressource proposée par Procopio et al. (2021). Nous comparons l’utilisation d’un transfert bilingue à un transfert multi-cibles pour l’analyse sémantique AMR translingue. Nous construisons également des données d’évaluation pour l’AMR français. Nous présentons enfin les premiers résultats d’analyse AMR automatique pour le français. Selon le jeu de test utilisé, notre parseur AMR entraîné de manière zéro-ressource, c’est-à-dire sans données d’entraînement, obtient des scores Smatch qui se situent entre 54,2 et 66,0.


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Fine-tuning pre-trained models for Automatic Speech Recognition, experiments on a fieldwork corpus of Japhug (Trans-Himalayan family)
Séverine Guillaume | Guillaume Wisniewski | Cécile Macaire | Guillaume Jacques | Alexis Michaud | Benjamin Galliot | Maximin Coavoux | Solange Rossato | Minh-Châu Nguyên | Maxime Fily
Proceedings of the Fifth Workshop on the Use of Computational Methods in the Study of Endangered Languages

This is a report on results obtained in the development of speech recognition tools intended to support linguistic documentation efforts. The test case is an extensive fieldwork corpus of Japhug, an endangered language of the Trans-Himalayan (Sino-Tibetan) family. The goal is to reduce the transcription workload of field linguists. The method used is a deep learning approach based on the language-specific tuning of a generic pre-trained representation model, XLS-R, using a Transformer architecture. We note difficulties in implementation, in terms of learning stability. But this approach brings significant improvements nonetheless. The quality of phonemic transcription is improved over earlier experiments; and most significantly, the new approach allows for reaching the stage of automatic word recognition. Subjective evaluation of the tool by the author of the training data confirms the usefulness of this approach.


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Contribution d’informations syntaxiques aux capacités de généralisation compositionelle des modèles seq2seq convolutifs (Assessing the Contribution of Syntactic Information for Compositional Generalization of seq2seq Convolutional Networks)
Diana Nicoleta Popa | William N. Havard | Maximin Coavoux | Eric Gaussier | Laurent Besacier
Actes de la 28e Conférence sur le Traitement Automatique des Langues Naturelles. Volume 1 : conférence principale

Les modèles neuronaux de type seq2seq manifestent d’étonnantes capacités de prédiction quand ils sont entraînés sur des données de taille suffisante. Cependant, ils échouent à généraliser de manière satisfaisante quand la tâche implique d’apprendre et de réutiliser des règles systématiques de composition et non d’apprendre simplement par imitation des exemples d’entraînement. Le jeu de données SCAN, constitué d’un ensemble de commandes en langage naturel associées à des séquences d’action, a été spécifiquement conçu pour évaluer les capacités des réseaux de neurones à apprendre ce type de généralisation compositionnelle. Dans cet article, nous nous proposons d’étudier la contribution d’informations syntaxiques sur les capacités de généralisation compositionnelle des réseaux de neurones seq2seq convolutifs.

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BERT-Proof Syntactic Structures: Investigating Errors in Discontinuous Constituency Parsing
Maximin Coavoux
Findings of the Association for Computational Linguistics: ACL-IJCNLP 2021

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Self-Supervised and Controlled Multi-Document Opinion Summarization
Hady Elsahar | Maximin Coavoux | Jos Rozen | Matthias Gallé
Proceedings of the 16th Conference of the European Chapter of the Association for Computational Linguistics: Main Volume

We address the problem of unsupervised abstractive summarization of collections of user generated reviews through self-supervision and control. We propose a self-supervised setup that considers an individual document as a target summary for a set of similar documents. This setting makes training simpler than previous approaches by relying only on standard log-likelihood loss and mainstream models. We address the problem of hallucinations through the use of control codes, to steer the generation towards more coherent and relevant summaries.


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FlauBERT: Unsupervised Language Model Pre-training for French
Hang Le | Loïc Vial | Jibril Frej | Vincent Segonne | Maximin Coavoux | Benjamin Lecouteux | Alexandre Allauzen | Benoit Crabbé | Laurent Besacier | Didier Schwab
Proceedings of the Twelfth Language Resources and Evaluation Conference

Language models have become a key step to achieve state-of-the art results in many different Natural Language Processing (NLP) tasks. Leveraging the huge amount of unlabeled texts nowadays available, they provide an efficient way to pre-train continuous word representations that can be fine-tuned for a downstream task, along with their contextualization at the sentence level. This has been widely demonstrated for English using contextualized representations (Dai and Le, 2015; Peters et al., 2018; Howard and Ruder, 2018; Radford et al., 2018; Devlin et al., 2019; Yang et al., 2019b). In this paper, we introduce and share FlauBERT, a model learned on a very large and heterogeneous French corpus. Models of different sizes are trained using the new CNRS (French National Centre for Scientific Research) Jean Zay supercomputer. We apply our French language models to diverse NLP tasks (text classification, paraphrasing, natural language inference, parsing, word sense disambiguation) and show that most of the time they outperform other pre-training approaches. Different versions of FlauBERT as well as a unified evaluation protocol for the downstream tasks, called FLUE (French Language Understanding Evaluation), are shared to the research community for further reproducible experiments in French NLP.

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Qu’apporte BERT à l’analyse syntaxique en constituants discontinus ? Une suite de tests pour évaluer les prédictions de structures syntaxiques discontinues en anglais (What does BERT contribute to discontinuous constituency parsing ? A test suite to evaluate discontinuous constituency structure predictions in English)
Maximin Coavoux
Actes de la 6e conférence conjointe Journées d'Études sur la Parole (JEP, 33e édition), Traitement Automatique des Langues Naturelles (TALN, 27e édition), Rencontre des Étudiants Chercheurs en Informatique pour le Traitement Automatique des Langues (RÉCITAL, 22e édition). Volume 2 : Traitement Automatique des Langues Naturelles

Cet article propose d’analyser les apports d’un modèle de langue pré-entraîné de type BERT (bidirectional encoder representations from transformers) à l’analyse syntaxique en constituants discontinus en anglais (PTB, Penn Treebank). Pour cela, nous réalisons une comparaison des erreurs d’un analyseur syntaxique dans deux configurations (i) avec un accès à BERT affiné lors de l’apprentissage (ii) sans accès à BERT (modèle n’utilisant que les données d’entraînement). Cette comparaison s’appuie sur la construction d’une suite de tests que nous rendons publique. Nous annotons les phrases de la section de validation du Penn Treebank avec des informations sur les phénomènes syntaxiques à l’origine des discontinuités. Ces annotations nous permettent de réaliser une évaluation fine des capacités syntaxiques de l’analyseur pour chaque phénomène cible. Nous montrons que malgré l’apport de BERT à la qualité des analyses (jusqu’à 95 en F1 ), certains phénomènes complexes ne sont toujours pas analysés de manière satisfaisante.

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FlauBERT : des modèles de langue contextualisés pré-entraînés pour le français (FlauBERT : Unsupervised Language Model Pre-training for French)
Hang Le | Loïc Vial | Jibril Frej | Vincent Segonne | Maximin Coavoux | Benjamin Lecouteux | Alexandre Allauzen | Benoît Crabbé | Laurent Besacier | Didier Schwab
Actes de la 6e conférence conjointe Journées d'Études sur la Parole (JEP, 33e édition), Traitement Automatique des Langues Naturelles (TALN, 27e édition), Rencontre des Étudiants Chercheurs en Informatique pour le Traitement Automatique des Langues (RÉCITAL, 22e édition). Volume 2 : Traitement Automatique des Langues Naturelles

Les modèles de langue pré-entraînés sont désormais indispensables pour obtenir des résultats à l’état-de-l’art dans de nombreuses tâches du TALN. Tirant avantage de l’énorme quantité de textes bruts disponibles, ils permettent d’extraire des représentations continues des mots, contextualisées au niveau de la phrase. L’efficacité de ces représentations pour résoudre plusieurs tâches de TALN a été démontrée récemment pour l’anglais. Dans cet article, nous présentons et partageons FlauBERT, un ensemble de modèles appris sur un corpus français hétérogène et de taille importante. Des modèles de complexité différente sont entraînés à l’aide du nouveau supercalculateur Jean Zay du CNRS. Nous évaluons nos modèles de langue sur diverses tâches en français (classification de textes, paraphrase, inférence en langage naturel, analyse syntaxique, désambiguïsation automatique) et montrons qu’ils surpassent souvent les autres approches sur le référentiel d’évaluation FLUE également présenté ici.


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Unlexicalized Transition-based Discontinuous Constituency Parsing
Maximin Coavoux | Benoît Crabbé | Shay B. Cohen
Transactions of the Association for Computational Linguistics, Volume 7

Lexicalized parsing models are based on the assumptions that (i) constituents are organized around a lexical head and (ii) bilexical statistics are crucial to solve ambiguities. In this paper, we introduce an unlexicalized transition-based parser for discontinuous constituency structures, based on a structure-label transition system and a bi-LSTM scoring system. We compare it with lexicalized parsing models in order to address the question of lexicalization in the context of discontinuous constituency parsing. Our experiments show that unlexicalized models systematically achieve higher results than lexicalized models, and provide additional empirical evidence that lexicalization is not necessary to achieve strong parsing results. Our best unlexicalized model sets a new state of the art on English and German discontinuous constituency treebanks. We further provide a per-phenomenon analysis of its errors on discontinuous constituents.

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Unsupervised Aspect-Based Multi-Document Abstractive Summarization
Maximin Coavoux | Hady Elsahar | Matthias Gallé
Proceedings of the 2nd Workshop on New Frontiers in Summarization

User-generated reviews of products or services provide valuable information to customers. However, it is often impossible to read each of the potentially thousands of reviews: it would therefore save valuable time to provide short summaries of their contents. We address opinion summarization, a multi-document summarization task, with an unsupervised abstractive summarization neural system. Our system is based on (i) a language model that is meant to encode reviews to a vector space, and to generate fluent sentences from the same vector space (ii) a clustering step that groups together reviews about the same aspects and allows the system to generate summary sentences focused on these aspects. Our experiments on the Oposum dataset empirically show the importance of the clustering step.

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Discontinuous Constituency Parsing with a Stack-Free Transition System and a Dynamic Oracle
Maximin Coavoux | Shay B. Cohen
Proceedings of the 2019 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 1 (Long and Short Papers)

We introduce a novel transition system for discontinuous constituency parsing. Instead of storing subtrees in a stack –i.e. a data structure with linear-time sequential access– the proposed system uses a set of parsing items, with constant-time random access. This change makes it possible to construct any discontinuous constituency tree in exactly 4n–2 transitions for a sentence of length n. At each parsing step, the parser considers every item in the set to be combined with a focus item and to construct a new constituent in a bottom-up fashion. The parsing strategy is based on the assumption that most syntactic structures can be parsed incrementally and that the set –the memory of the parser– remains reasonably small on average. Moreover, we introduce a provably correct dynamic oracle for the new transition system, and present the first experiments in discontinuous constituency parsing using a dynamic oracle. Our parser obtains state-of-the-art results on three English and German discontinuous treebanks.


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Privacy-preserving Neural Representations of Text
Maximin Coavoux | Shashi Narayan | Shay B. Cohen
Proceedings of the 2018 Conference on Empirical Methods in Natural Language Processing

This article deals with adversarial attacks towards deep learning systems for Natural Language Processing (NLP), in the context of privacy protection. We study a specific type of attack: an attacker eavesdrops on the hidden representations of a neural text classifier and tries to recover information about the input text. Such scenario may arise in situations when the computation of a neural network is shared across multiple devices, e.g. some hidden representation is computed by a user’s device and sent to a cloud-based model. We measure the privacy of a hidden representation by the ability of an attacker to predict accurately specific private information from it and characterize the tradeoff between the privacy and the utility of neural representations. Finally, we propose several defense methods based on modified training objectives and show that they improve the privacy of neural representations.


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Cross-lingual RST Discourse Parsing
Chloé Braud | Maximin Coavoux | Anders Søgaard
Proceedings of the 15th Conference of the European Chapter of the Association for Computational Linguistics: Volume 1, Long Papers

Discourse parsing is an integral part of understanding information flow and argumentative structure in documents. Most previous research has focused on inducing and evaluating models from the English RST Discourse Treebank. However, discourse treebanks for other languages exist, including Spanish, German, Basque, Dutch and Brazilian Portuguese. The treebanks share the same underlying linguistic theory, but differ slightly in the way documents are annotated. In this paper, we present (a) a new discourse parser which is simpler, yet competitive (significantly better on 2/3 metrics) to state of the art for English, (b) a harmonization of discourse treebanks across languages, enabling us to present (c) what to the best of our knowledge are the first experiments on cross-lingual discourse parsing.

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Incremental Discontinuous Phrase Structure Parsing with the GAP Transition
Maximin Coavoux | Benoît Crabbé
Proceedings of the 15th Conference of the European Chapter of the Association for Computational Linguistics: Volume 1, Long Papers

This article introduces a novel transition system for discontinuous lexicalized constituent parsing called SR-GAP. It is an extension of the shift-reduce algorithm with an additional gap transition. Evaluation on two German treebanks shows that SR-GAP outperforms the previous best transition-based discontinuous parser (Maier, 2015) by a large margin (it is notably twice as accurate on the prediction of discontinuous constituents), and is competitive with the state of the art (Fernández-González and Martins, 2015). As a side contribution, we adapt span features (Hall et al., 2014) to discontinuous parsing.

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Multilingual Lexicalized Constituency Parsing with Word-Level Auxiliary Tasks
Maximin Coavoux | Benoît Crabbé
Proceedings of the 15th Conference of the European Chapter of the Association for Computational Linguistics: Volume 2, Short Papers

We introduce a constituency parser based on a bi-LSTM encoder adapted from recent work (Cross and Huang, 2016b; Kiperwasser and Goldberg, 2016), which can incorporate a lower level character biLSTM (Ballesteros et al., 2015; Plank et al., 2016). We model two important interfaces of constituency parsing with auxiliary tasks supervised at the word level: (i) part-of-speech (POS) and morphological tagging, (ii) functional label prediction. On the SPMRL dataset, our parser obtains above state-of-the-art results on constituency parsing without requiring either predicted POS or morphological tags, and outputs labelled dependency trees.

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Représentation et analyse automatique des discontinuités syntaxiques dans les corpus arborés en constituants du français (Representation and parsing of syntactic discontinuities in French constituent treebanks)
Maximin Coavoux | Benoît Crabbé
Actes des 24ème Conférence sur le Traitement Automatique des Langues Naturelles. Volume 1 - Articles longs

Nous présentons de nouvelles instanciations de trois corpus arborés en constituants du français, où certains phénomènes syntaxiques à l’origine de dépendances à longue distance sont représentés directement à l’aide de constituants discontinus. Les arbres obtenus relèvent de formalismes grammaticaux légèrement sensibles au contexte (LCFRS). Nous montrons ensuite qu’il est possible d’analyser automatiquement de telles structures de manière efficace à condition de s’appuyer sur une méthode d’inférence approximative. Pour cela, nous présentons un analyseur syntaxique par transitions, qui réalise également l’analyse morphologique et l’étiquetage fonctionnel des mots de la phrase. Enfin, nos expériences montrent que la rareté des phénomènes concernés dans les données françaises pose des difficultés pour l’apprentissage et l’évaluation des structures discontinues.


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Prédiction structurée pour l’analyse syntaxique en constituants par transitions : modèles denses et modèles creux [Structured Prediction for Transition-based Constituent Parsing: Dense and Sparse Models]
Maximin Coavoux | Benoît Crabbé
Traitement Automatique des Langues, Volume 57, Numéro 1 : Varia [Varia]

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Neural Greedy Constituent Parsing with Dynamic Oracles
Maximin Coavoux | Benoît Crabbé
Proceedings of the 54th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)


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Comparaison d’architectures neuronales pour l’analyse syntaxique en constituants
Maximin Coavoux | Benoît Crabbé
Actes de la 22e conférence sur le Traitement Automatique des Langues Naturelles. Articles longs

L’article traite de l’analyse syntaxique lexicalisée pour les grammaires de constituants. On se place dans le cadre de l’analyse par transitions. Les modèles statistiques généralement utilisés pour cette tâche s’appuient sur une représentation non structurée du lexique. Les mots du vocabulaire sont représentés par des symboles discrets sans liens entre eux. À la place, nous proposons d’utiliser des représentations denses du type plongements (embeddings) qui permettent de modéliser la similarité entre symboles, c’est-à-dire entre mots, entre parties du discours et entre catégories syntagmatiques. Nous proposons d’adapter le modèle statistique sous-jacent à ces nouvelles représentations. L’article propose une étude de 3 architectures neuronales de complexité croissante et montre que l’utilisation d’une couche cachée non-linéaire permet de tirer parti des informations données par les plongements.