Publications

DiffVersify: A scalable approach to differentiable pattern mining with coverage regularization

By Thibaut Chataing, Julien Perez, Marc Plantevit, Céline Robardet

2024-01-10

In Machine learning and knowledge discovery in databases. Research track - european conference, ECML PKDD 2024, vilnius, lithuania, september 9-13, 2024, proceedings, part VI

Abstract

Pattern mining addresses the challenge of automatically identifying interpretable and discriminative patterns within data. Recent approaches, leveraging differentiable approach through neural autoencoder with class recovery, have achieved encouraging results but tend to fall short as the magnitude of the noise and the number of underlying features increase in the data. Empirically, one can observe that the number of discovered patterns tend to be limited in these challenging contexts. In this article, we present a differentiable binary model that integrates a new regularization technique to enhance pattern coverage. Besides, we introduce an innovative pattern decoding strategy taking advantage of non-negative matrix factorization (NMF), extending beyond conventional thresholding methods prevalent in existing approaches. Experiments on four realworld datasets exhibit superior performances of DiffVersify in terms of the ROC-AUC metric. On synthetic data, we observe an increase in the similarity between the discovered patterns and the ground truth. Finally, using several metrics to finely evaluate the quality of the patterns in regard to the data, we show the global effectiveness of the approach.

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Additive margin in contrastive self-supervised frameworks to learn discriminative speaker representations

By Theo Lepage, Reda Dehak

2024-01-01

In The speaker and language recognition workshop (odyssey 2024)

Abstract

Self-Supervised Learning (SSL) frameworks became the standard for learning robust class representations by benefiting from large unlabeled datasets. For Speaker Verification (SV), most SSL systems rely on contrastive-based loss functions. We explore different ways to improve the performance of these techniques by revisiting the NT-Xent contrastive loss. Our main contribution is the definition of the NT-Xent-AM loss and the study of the importance of Additive Margin (AM) in SimCLR and MoCo SSL methods to further separate positive from negative pairs. Despite class collisions, we show that AM enhances the compactness of same-speaker embeddings and reduces the number of false negatives and false positives on SV. Additionally, we demonstrate the effectiveness of the symmetric contrastive loss, which provides more supervision for the SSL task. Implementing these two modifications to SimCLR improves performance and results in 7.85% EER on VoxCeleb1-O, outperforming other equivalent methods.

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Apprentissage interprétable de la criminalité en france (2012-2021)

By Nida Meddouri, David Beserra

2024-01-01

In Actes de l’atelier gestion et analyse des données spatiales et temporelles

Abstract

L’activité criminelle en France a connu une évolution significative au cours des deux dernières décennies, marquée par la recrudescence des actes de malveillance, notamment liés aux mouvements sociaux et syndicaux, aux émeutes, ainsi qu’au terrorisme. Dans ce contexte difficile, l’utilisation de techniques issues de l’intelligence artificielle pourrait offrir de nombreuses perspectives pour renforcer la sûreté publique et privée en France. Un exemple de cette approche est l’analyse spatio-temporelle des données de criminalité, déjà couronnée de succès au Brésil (Da Silva et al., 2020), au Proche-Orient (Tolan et al., 2015), et dans d’autres pays. Dans le cadre de ce travail, nous explorons la possibilité d’appliquer cette approche au contexte français.

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Concurrent stochastic lossy channel games

By Daniel Stan, Muhammad Najib, Anthony Widjaja Lin, Parosh Aziz Abdulla

2024-01-01

In Proceedings of the 32nd EACSL annual conference on computer science logic (CSL’24), february 19-23, 2024, naples, italy

Abstract

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Enhanced neonatal screening for sickle cell disease: Human-guided deep learning with CNN on isoelectric focusing images

By Kpangni Alex Jérémie Koua, Cheikh Talibouya Diop, Lamine Diop, Mamadou Diop

2024-01-01

In Journal of Infrastructure, Policy and Development

Abstract

Accurate detection of abnormal hemoglobin variations is paramount for early diagnosis of sickle cell disease (SCD) in newborns. Traditional methods using isoelectric focusing (IEF) with agarose gels are technician-dependent and face limitations like inconsistent image quality and interpretation challenges. This study proposes a groundbreaking solution using deep learning (DL) and artificial intelligence (AI) while ensuring human guidance throughout the process. The system analyzes IEF gel images with convolutional neural networks (CNNs), achieving over 98% accuracy in identifying various SCD profiles, far surpassing the limitations of traditional methods. Furthermore, the system addresses ambiguities by incorporating an “Unconfirmed” category for unclear cases and assigns probability values to each classification, empowering clinicians with crucial information for informed decisions. This AI-powered tool, named SCScreen, seamlessly integrates machine learning with medical expertise, offering a robust, efficient, and accurate solution for SCD screening. Notably, SCScreen tackles the previously challenging diagnosis of major sickle cell syndromes (SDM) in newborns. This research has the potential to revolutionize SCD management. By strengthening screening platforms and potentially reducing costs, SCScreen paves the way for improved healthcare outcomes for newborns with SCD, potentially saving lives and improving the quality of life for affected individuals.

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Exploring WavLM back-ends for speech spoofing and deepfake detection

Abstract

This paper describes our submitted systems to the ASVspoof 5 Challenge Track 1: Speech Deepfake Detection - Open Condition, which consists of a stand-alone speech deepfake (bonafide vs spoof) detection task. Recently, large-scale self-supervised models become a standard in Automatic Speech Recognition (ASR) and other speech processing tasks. Thus, we leverage a pre-trained WavLM as a front-end model and pool its representations with different back-end techniques. The complete framework is fine-tuned using only the trained dataset of the challenge, similar to the close condition. Besides, we adopt data-augmentation by adding noise and reverberation using MUSAN noise and RIR datasets. We also experiment with codec augmentations to increase the performance of our method. Ultimately, we use the Bosaris toolkit for score calibration and system fusion to get better Cllr scores. Our fused system achieves $0.0937$ minDCF, $3.42%$ EER, $0.1927$ Cllr, and $0.1375$ actDCF.

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Towards supervised performance on speaker verification with self-supervised learning by leveraging large-scale ASR models

Abstract

Recent advancements in Self-Supervised Learning (SSL) have shown promising results in Speaker Verification (SV). However, narrowing the performance gap with supervised systems remains an ongoing challenge. Several studies have observed that speech representations from large-scale ASR models contain valuable speaker information. This work explores the limitations of fine-tuning these models for SV using an SSL contrastive objective in an end-to-end approach. Then, we propose a framework to learn speaker representations in an SSL context by fine-tuning a pre-trained WavLM with a supervised loss using pseudo-labels. Initial pseudo-labels are derived from an SSL DINO-based model and are iteratively refined by clustering the model embeddings. Our method achieves 0.99% EER on VoxCeleb1-O, establishing the new state-of-the-art on self-supervised SV. As this performance is close to our supervised baseline of 0.94% EER, this contribution is a step towards supervised performance on SV with SSL.

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