Urchade Zaratiana


2024

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GLiNER: Generalist Model for Named Entity Recognition using Bidirectional Transformer
Urchade Zaratiana | Nadi Tomeh | Pierre Holat | Thierry Charnois
Proceedings of the 2024 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)

Named Entity Recognition (NER) is essential in various Natural Language Processing (NLP) applications. Traditional NER models are effective but limited to a set of predefined entity types. In contrast, Large Language Models (LLMs) can extract arbitrary entities through natural language instructions, offering greater flexibility. However, their size and cost, particularly for those accessed via APIs like ChatGPT, make them impractical in resource-limited scenarios. In this paper, we introduce a compact NER model trained to identify any type of entity. Leveraging a bidirectional transformer encoder, our model, GLiNER, facilitates parallel entity extraction, an advantage over the slow sequential token generation of LLMs. Through comprehensive testing, GLiNER demonstrate strong performance, outperforming both ChatGPT and fine-tuned LLMs in zero-shot evaluations on various NER benchmarks.

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FI Group at SemEval-2024 Task 8: A Syntactically Motivated Architecture for Multilingual Machine-Generated Text Detection
Maha Ben-fares | Urchade Zaratiana | Simon Hernandez | Pierre Holat
Proceedings of the 18th International Workshop on Semantic Evaluation (SemEval-2024)

In this paper, we present the description of our proposed system for Subtask A - multilingual track at SemEval-2024 Task 8, which aims to classify if text has been generated by an AI or Human. Our approach treats binary text classification as token-level prediction, with the final classification being the average of token-level predictions. Through the use of rich representations of pre-trained transformers, our model is trained to selectively aggregate information from across different layers to score individual tokens, given that each layer may contain distinct information. Notably, our model demonstrates competitive performance on the test dataset, achieving an accuracy score of 95.8%. Furthermore, it secures the 2nd position in the multilingual track of Subtask A, with a mere 0.1% behind the leading system.

2023

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Filtered Semi-Markov CRF
Urchade Zaratiana | Nadi Tomeh | Niama El Khbir | Pierre Holat | Thierry Charnois
Findings of the Association for Computational Linguistics: EMNLP 2023

Semi-Markov CRF has been proposed as an alternative to the traditional Linear Chain CRF for text segmentation tasks such as Named Entity Recognition (NER). Unlike CRF, which treats text segmentation as token-level prediction, Semi-CRF considers segments as the basic unit, making it more expressive. However, Semi-CRF suffers from two major drawbacks: (1) quadratic complexity over sequence length, as it operates on every span of the input sequence, and (2) inferior performance compared to CRF for sequence labeling tasks like NER. In this paper, we introduce Filtered Semi-Markov CRF, a variant of Semi-CRF that addresses these issues by incorporating a filtering step to eliminate irrelevant segments, reducing complexity and search space. Our approach is evaluated on several NER benchmarks, where it outperforms both CRF and Semi-CRF while being significantly faster. The implementation of our method is available on Github.

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Sélection globale de segments pour la reconnaissance d’entités nommées
Urchade Zaratiana | Niama El Khbir | Pierre Holat | Nadi Tomeh | Thierry Charnois
Actes de CORIA-TALN 2023. Actes de la 30e Conférence sur le Traitement Automatique des Langues Naturelles (TALN), volume 4 : articles déjà soumis ou acceptés en conférence internationale

La reconnaissance d’entités nommées est une tâche importante en traitement automatique du langage naturel avec des applications dans de nombreux domaines. Dans cet article, nous décrivons une nouvelle approche pour la reconnaissance d’entités nommées, dans laquelle nous produisons un ensemble de segmentations en maximisant un score global. Pendant l’entraînement, nous optimisons notre modèle en maximisant la probabilité de la segmentation correcte. Pendant l’inférence, nous utilisons la programmation dynamique pour sélectionner la meilleure segmentation avec une complexité linéaire. Nous prouvons que notre approche est supérieure aux modèles champs de Markov conditionnels et semi-CMC pour la reconnaissance d’entités nommées.

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Cross-Dialectal Named Entity Recognition in Arabic
Niama El Elkhbir | Urchade Zaratiana | Nadi Tomeh | Thierry Charnois
Proceedings of ArabicNLP 2023

In this paper, we study the transferability of Named Entity Recognition (NER) models between Arabic dialects. This question is important because the available manually-annotated resources are not distributed equally across dialects: Modern Standard Arabic (MSA) is much richer than other dialects for which little to no datasets exist. How well does a NER model, trained on MSA, perform on other dialects? To answer this question, we construct four datasets. The first is an MSA dataset extracted from the ACE 2005 corpus. The others are datasets for Egyptian, Morocan and Syrian which we manually annotate following the ACE guidelines. We train a span-based NER model on top of a pretrained language model (PLM) encoder on the MSA data and study its performance on the other datasets in zero-shot settings. We study the performance of multiple PLM encoders from the literature and show that they achieve acceptable performance with no annotation effort. Our annotations and models are publicly available (https://github.com/niamaelkhbir/Arabic-Cross-Dialectal-NER).

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LIPN at WojoodNER shared task: A Span-Based Approach for Flat and Nested Arabic Named Entity Recognition
Niama El Khbir | Urchade Zaratiana | Nadi Tomeh | Thierry Charnois
Proceedings of ArabicNLP 2023

The Wojood Named Entity Recognition (NER) shared task introduces a comprehensive Arabic NER dataset encompassing both flat and nested entity tasks, addressing the challenge of limited Arabic resources. In this paper, we present our team LIPN approach to addressing the two subtasks of WojoodNER SharedTask. We frame NER as a span classification problem. We employ a pretrained language model for token representations and neural network classifiers. We use global decoding for flat NER and a greedy strategy for nested NER. Our model secured the first position in flat NER and the fourth position in nested NER during the competition, with an F-score of 91.96 and 92.45 respectively. Our code is publicly available (https://github.com/niamaelkhbir/LIPN-at-WojoodSharedTask).

2022

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GNNer: Reducing Overlapping in Span-based NER Using Graph Neural Networks
Urchade Zaratiana | Nadi Tomeh | Pierre Holat | Thierry Charnois
Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics: Student Research Workshop

There are two main paradigms for Named Entity Recognition (NER): sequence labelling and span classification. Sequence labelling aims to assign a label to each word in an input text using, for example, BIO (Begin, Inside and Outside) tagging, while span classification involves enumerating all possible spans in a text and classifying them into their labels. In contrast to sequence labelling, unconstrained span-based methods tend to assign entity labels to overlapping spans, which is generally undesirable, especially for NER tasks without nested entities. Accordingly, we propose GNNer, a framework that uses Graph Neural Networks to enrich the span representation to reduce the number of overlapping spans during prediction. Our approach reduces the number of overlapping spans compared to strong baseline while maintaining competitive metric performance. Code is available at https://github.com/urchade/GNNer.

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Named Entity Recognition as Structured Span Prediction
Urchade Zaratiana | Nadi Tomeh | Pierre Holat | Thierry Charnois
Proceedings of the Workshop on Unimodal and Multimodal Induction of Linguistic Structures (UM-IoS)

Named Entity Recognition (NER) is an important task in Natural Language Processing with applications in many domains. While the dominant paradigm of NER is sequence labelling, span-based approaches have become very popular in recent times but are less well understood. In this work, we study different aspects of span-based NER, namely the span representation, learning strategy, and decoding algorithms to avoid span overlap. We also propose an exact algorithm that efficiently finds the set of non-overlapping spans that maximizes a global score, given a list of candidate spans. We performed our study on three benchmark NER datasets from different domains. We make our code publicly available at https://github.com/urchade/span-structured-prediction.

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Global Span Selection for Named Entity Recognition
Urchade Zaratiana | Niama El khbir | Pierre Holat | Nadi Tomeh | Thierry Charnois
Proceedings of the Workshop on Unimodal and Multimodal Induction of Linguistic Structures (UM-IoS)

Named Entity Recognition (NER) is an important task in Natural Language Processing with applications in many domains. In this paper, we describe a novel approach to named entity recognition, in which we output a set of spans (i.e., segmentations) by maximizing a global score. During training, we optimize our model by maximizing the probability of the gold segmentation. During inference, we use dynamic programming to select the best segmentation under a linear time complexity. We prove that our approach outperforms CRF and semi-CRF models for Named Entity Recognition. We will make our code publicly available.