Publications

2024

• TEE-Time: A Dynamic Cache Timing Analysis Tool for Trusted Execution Environments
  
  • Forcioli Quentin
  • Chaudhuri Sumanta
  • Danger Jean-Luc
  , 2024 (25), pp.1-8. In this article, we present a tool to analyze cache timing vulnerabilities in trusted execution environments. First, we present a platform based on the well-known gem5 simulator capable of booting GlobalPlatform Compliant TEEs for ARMV8 architecture. Next, we present the associated GDB instrumentation which allows us to dynamically reconfigure the gem5 simulator and access detailed micro-architectural state after each simulation step. Unmodified Linux/TEE binaries can be run on this platform, from which detailed execution and cache access traces are gathered and analyzed on-the-fly.We demonstrate the usage of this tool, first with an in-vitro experiment to explain the concepts of Key-Cache lines, Key-Execution Points, a method to rank these lines in an increasing order of vulnerability, and code coverage. We show that real vulnerabilities can be detected with our tool, in an otherwise constant-time RSA implementation inside an open Source TEE called OP-TEE. (10.1109/ISQED60706.2024.10528744)
  DOI : 10.1109/ISQED60706.2024.10528744
• A fully differentiable model for unsupervised singing voice separation
  
  • Richard Gael
  • Chouteau Pierre
  • Torres Bernardo
  , 2024. A novel model was recently proposed by Schulze-Forster et al. in [1] for unsupervised music source separation. This model allows to tackle some of the major shortcomings of existing source separation frameworks. Specifically, it eliminates the need for isolated sources during training, performs efficiently with limited data, and can handle homogeneous sources (such as singing voice). But, this model relies on an external multipitch estimator and incorporates an Ad hoc voice assignment procedure. In this paper, we propose to extend this framework and to build a fully differentiable model by integrating a multipitch estimator and a novel differentiable assignment module within the core model. We show the merits of our approach through a set of experiments, and we highlight in particular its potential for processing diverse and unseen data. (10.1109/ICASSP48485.2024.10447244)
  DOI : 10.1109/ICASSP48485.2024.10447244
• Alvolution - al and digital technologies in the European Union
  
  • Poptcheva Eva
  • Vanderborght Bram
  • Colom Miguel
  • Binkytė Rūta
  • Balalau Oana
  • Goga Oana
  • Debar Hervé
  • Coupechoux Marceau
  • Herrera Juan
  , 2024. This document compiles the extended versions of the main contributions presented in the scientific event 'AIvolution', on AI and digital technologies in the EU, organized by MEP Eva-Maria Poptcheva (Renew Europe) and Juan-Antonio Cordero-Fuertes (IP Paris), and hosted at the European Parliament (EP), on November 16th, 2023.
• MERLIN-Seg: self-supervised despeckling for label-efficient semantic segmentation
  
  • Dalsasso Emanuele
  • Rambour Clément
  • Trouvé Nicolas
  • Thome Nicolas
  Computer Vision and Image Understanding, Elsevier, 2024, 241. Remote sensing satellites acquire a continuous stream of data on a daily basis. As most of those data are unlabeled, the development of algorithms requiring weak supervision is of paramount importance. In this paper, we show that the need for annotation for Synthetic Aperture Radar data can be reduced by coupling a despeckling task (self-supervised) and a segmentation task (supervised). The proposed self-supervised learning framework, called MERLIN-Seg, has been trained for building footprint extraction and achieves favorable performances even with 1% of annotated data. We show that conditioning the network on despeckling without labels is beneficial for supervised segmentation. Our experiments demonstrate that the joint training of the two tasks achieves better performances than a vanilla segmentation network in terms of IoU, F1 score, and accuracy on both simulated and real SAR images. (10.1016/j.cviu.2024.103940)
  DOI : 10.1016/j.cviu.2024.103940
• Structure-informed Positional Encoding for Music Generation
  
  • Agarwal Manvi
  • Wang Changhong
  • Richard Gaël
  , 2024. Music generated by deep learning methods often suffers from a lack of coherence and long-term organization. Yet, multi-scale hierarchical structure is a distinctive feature of music signals. To leverage this information, we propose a structure-informed positional encoding framework for music generation with Transformers. We design three variants in terms of absolute, relative and non-stationary positional information. We comprehensively test them on two symbolic music generation tasks: next-timestep prediction and accompaniment generation. As a comparison, we choose multiple baselines from the literature and demonstrate the merits of our methods using several musically-motivated evaluation metrics. In particular, our methods improve the melodic and structural consistency of the generated pieces. (10.1109/ICASSP48485.2024.10448149)
  DOI : 10.1109/ICASSP48485.2024.10448149
• Cybersécurité des maisons intelligentes : architectures, solutions et technologies
  
  • Khatoun Rida
  , 2024, pp.1-314. Les maisons intelligentes utilisent des dispositifs connectés à Internet, l’intelligence artificielle, des protocoles et de multiples technologies afin de permettre à leurs résidents de surveiller à distance leurs maisons et de les gérer à l’aide d’un Smartphone. Amazon, Apple et Google, entre autres, ont lancé leurs propres dispositifs pour maisons intelligentes et de nouvelles solutions sont en cours de développement. Cependant, le nombre de cyberattaques à l’encontre des maisons intelligentes est en augmentation, et ce dans le but d’accéder à des informations privées ou de commettre des actes de vandalisme numérique. Par conséquent, choisir une bonne architecture de cybersécurité pour la maison et comprendre les risques sont autant de points essentiels à étudier avant de connecter une maison à Internet. Cet ouvrage s’adresse aux personnes qui souhaitent comprendre les architectures, les protocoles et les différentes technologies utilisés dans une maison intelligente. Il présente également des solutions proposées par la communauté de recherche pour contrer ces risques.
• Effets environnementaux de la 5G (Partie 1) : La technologie 5G
  
  • Ciblat Philippe
  • Combaz Jacques
  • Coupechoux Marceau
  • Marquet Kevin
  • Orgerie Anne-Cécile
  1024 : Bulletin de la Société Informatique de France, Société Informatique de France, 2024 (23), pp.53-72. Ce document a pour objectif de rassembler les connaissances actuelles liées aux effets environnementaux de la 5G. Il s’articule autour de questions liées à ces effets. Pour cela, il est organisé en trois partie. La première présentée ici donne les bases nécessaires à la compréhension de la technologie elle-même. La deuxième détaillera les services rendus possibles par la 5G. La dernière se penchera enfin sur les effets environnementaux du déploiement de la 5G. (10.48556/SIF.1024.23.53)
  DOI : 10.48556/SIF.1024.23.53
• Absorptive nature of scattering coefficients in stress-energy tensor formalism for room acoustics
  
  • Polack Jean-Dominique
  • Dujourdy Hugo
  • Badeau Roland
  Journal of the Acoustical Society of America, Acoustical Society of America, 2024, 155 (4), pp.2339 - 2346. In the stress-energy tensor formalism, the symmetry between absorption and scattering coefficients, as proven by measurements combined with simulations, is counterintuitive. By introducing the wall admittance, we show that the scattering coefficient is partly created by the real part of the wall admittance combined with the active intensity, that is, is partly due to absorption. However, for curved surfaces or finite source distances, it also depends on the imaginary part of the wall admittance in combination with the reactive intensity, which confers its genuine scattering properties inversely proportional to the distances to the sources. Thus, for plane waves impinging on plane boundaries, or purely real admittances, scattering reduces to absorption. (10.1121/10.0025468)
  DOI : 10.1121/10.0025468
• Device-independent quantum key distribution based on routed Bell tests
  
  • Le Roy-Deloison Tristan
  • Lobo Edwin Peter
  • Pauwels Jef
  • Pironio Stefano
  PRX Quantum, APS Physics, 2024, 6 (2), pp.020311. Photon losses are the main obstacle to fully photonic implementations of device-independent quantum key distribution (DIQKD). Motivated by recent work showing that routed Bell scenarios offer increased robustness to detection inefficiencies for the certification of long-range quantum correlations, we investigate DIQKD protocols based on a routed setup. In these protocols, in some of the test rounds, photons from the source are routed by an actively controlled switch to a nearby test device instead of the distant one. We show how to analyze the security of these protocols and compute lower bounds on the key rates using non-commutative polynomial optimization and the Brown-Fawzi-Fazwi method. We determine lower bounds on the asymptotic key rates of several simple two-qubit routed DIQKD protocols based on CHSH or BB84 correlations and compare their performance to standard protocols. We find that in an ideal case routed DIQKD protocols can significantly improve detection efficiency requirements, by up to $\sim 30\%$, compared to their non-routed counterparts. Notably, the routed BB84 protocol achieves a positive key rate with a detection efficiency as low as $50\%$ for the distant device, the minimal threshold for any QKD protocol featuring two untrusted measurements. However, the advantages we find are highly sensitive to noise and losses affecting the short-range correlations involving the additional test device. (10.1103/PRXQuantum.6.020311)
  DOI : 10.1103/PRXQuantum.6.020311
• Software countermeasures against the multiple instructions skip fault model
  
  • Khuat Vanthanh
  • Dutertre Jean-Max
  • Danger Jean-Luc
  Microelectronics Reliability, Elsevier, 2024, 155, pp.115370. In this work, we proposed two software countermeasures (CMs) for the detection of multiple instructions skips caused by Fault Injection (FI). The first CM is based on code duplication and uses a hardware dedicated counter. The implementation of this method consists in the duplication of instructions previously turned into an idempotent form and the insertion of dedicated instructions incrementing a hardware counter in between the groups of duplicated instructions. The second CM is based on the insertion of Sensitive instruction (SI)s into a block of instructions as sensors of instruction skips. The SI is chosen based on the observed Fault Model (FM) at bit level. We experimentally validated the effectiveness of the two CMs in a 32-bit Microcontroller Unit (MCU) using Laser Fault Injection (LFI) and Electromagnetic Fault Injection (EMFI). First, the skip of multiple instructions was obtained with a fault rate of 100%. The FM at bit level was identified to be bit-reset rather than bit-set. Second, we carried out LFI and EMFI experiments to the protected codes to validate the effectiveness of the CMs. In both cases, the results showed that the proposed methods are effective to detect multiple instructions skip faults. (10.1016/j.microrel.2024.115370)
  DOI : 10.1016/j.microrel.2024.115370
• A Highly Flexible Passive/Active Discrete-Time Delta-Sigma Receiver
  
  • Nguyen Minh Tien
  • Jabbour Chadi
  • Ben Kalaia Karim
  • Le Hanh-Phuc
  • Nguyen Ngoc
  • Nguyen Van-Tam
  Electronics, MDPI, 2024, 13 (7), pp.1295. This paper presents a fourth-order discrete-time direct RF-to-digital Delta-Sigma receiver architecture for flexible receivers with a wide frequency range. The use of a current-driven passive mixer with RF feedback enables high-Q bandpass filtering and relaxes the linearity requirement of the RF amplifier. In addition, the reconfigurable passive/active loop filter offers a good compromise between power consumption, linearity, and dynamic range. The other important feature of the proposed architecture is the use of a sampling frequency that is a divisor of the LO frequency. This solves several problems such as the upmixing of quantization noise, the need to reconfigure the Delta-Sigma loop when changing the LO frequency, and the use of two independent clocks for the LO and the sampling frequency. The circuit was implemented using 65 nm CMOS technology. The I/Q Direct Delta-Sigma receiver has an RF bandwidth of 20 MHz and a sampling frequency of 400 MHz. Measurement results show a very high dynamic range of up to 80 dB with a peak SNDR of 46 dB for a power consumption of 46 mW at 800 MHz. (10.3390/electronics13071295)
  DOI : 10.3390/electronics13071295
• Grandes Constellations de Satellites : Enjeux et Impacts
  
  • Baccelli François
  • Candel Sébastien
  • Perrin Guy
  • Puget Jean-Loup
  , 2024. Le nouvel âge spatial (NewSpace) marque l’avènement d’une ère nouvelle dans l’utilisation de l’espace caractérisée par une ouverture de l’espace à de nouveaux acteurs fondée sur de nouvelles technologies spatiales, par de nouvelles fonctionnalités pour les satellites mis en orbite et par le développement de constellations de satellites, principalement dans les domaines des communications et de l’observation de la Terre. Ces développements s’appuient sur des avancées scientifiques et technologiques de premier plan ainsi que sur des investissements publics et privés considérables, notamment aux États-Unis, en Chine et dans une moindre mesure en Europe. Des flottes de petits satellites en orbite basse ou moyenne viennent remplacer ou s’ajouter aux grands satellites géostationnaires qui prédominaient dans la phase précédente. Alors que l’espace était auparavant réservé à un petit nombre d’États et de grands groupes industriels, on observe actuellement l’émergence de nouveaux États spatiaux, de nouveaux groupes industriels comme SpaceX ou Amazon, ainsi que d’un grand nombre de jeunes pousses. On note l’émergence d’entreprises disposant de capacités de lancement, de fabrication de satellites et qui prennent également le rôle d’opérateurs de télécommunications et de producteurs de contenu. Le résultat le plus visible du déploiement de ces nouveaux réseaux spatiaux est de permettre des connexions Internet à haut débit et faible latence en tout point du globe terrestre. Combinés à des capacités d’observation de la Terre, ces nouveaux moyens de communications permettent aussi d’agir en temps-réel dans toute région, y compris dans celles dépourvues d’équipements autres que les terminaux. Ces réseaux spatiaux ont, de plus, de remarquables propriétés de résilience en comparaison des réseaux terrestres. Des considérations géostratégiques et militaires se combinent donc avec des modèles économiques en évolution rapide pour expliquer les investissements massifs en cours dans ce domaine. Toutefois, l’absence de régulation internationale du domaine conduit à une course pour l’occupation des orbites et des fréquences, course qui a déjà de graves conséquences sur tout un ensemble de domaines. Ces constellations auront potentiellement un impact très négatif sur l’astronomie dans le domaine optique visible et infrarouge ainsi que sur la radioastronomie. Elles posent aussi un problème majeur qui est celui de l’encombrement de l’espace avec l’augmentation du nombre des débris satellisés issus des lancements ou des collisions entre satellites et avec la possible atteinte d’une phase de collisions en chaîne. De plus, d’un point de vue environnemental, les conséquences d’une multiplication des lancements et des rentrées incontrôlées dans l’atmosphère sont, elles aussi, préoccupantes. Par ailleurs, cette absence de régulation du domaine conduit aussi à une perte de souveraineté puisque ces nouveaux réseaux de communications satellitaires n’appliquent aucune des règles que les États imposent aux réseaux de communications terrestres opérant sur leurs territoires. Une solution durable et globale doit être apportée à ces problèmes, avant que des dommages majeurs et potentiellement irréversibles soient infligés à l’environnement de la planète, aux équilibres géostratégiques, à la démocratie et à la science. Si l’Académie des sciences considère que la France et l’Europe doivent renforcer leurs actions scientifiques et industrielles dans ce domaine pour pouvoir bénéficier des avancées remarquables de ces nouveaux réseaux et disposer à terme d’un réseau de communication résilient et sécurisé, elle recommande aussi de travailler en parallèle au renforcement de la régulation du domaine dans le but de garantir un accès durable aux ressources orbitales et fréquentielles, ainsi qu’une protection des domaines négativement impactés, au premier rang desquels l’astronomie et l’environnement. (10.62686/2)
  DOI : 10.62686/2
• Large Satellite Constellations: Challenges and Impact
  
  • Baccelli François
  • Candel Sébastien
  • Perrin Guy
  • Puget Jean-Loup
  , 2024. The New Space Age (NewSpace) marks the advent of a new era in the use of space, characterized by the opening of space to new players, the use of new space technologies, new functionalities for satellites in orbit, and the development of satellite constellations, mainly in the fields of communications and Earth observation. These developments are underpinned by first-rate scientific and technological advances, as well as considerable public and private investment, in particular in the USA, China and, to a lesser extent, Europe. Fleets of small low- and medium-orbit satellites are replacing or complementing the large geostationary satellites that predominated in the previous period. Whereas space used to be reserved to a small number of states and major industrial groups, one is now witnessing the emergence of new space states, new industrial groups such as SpaceX or Amazon, and many start-ups. One also observes the emergence of companies with launching and satellite manufacturing capacities, which are also taking on the role of telecommunication operators and content producers. The most visible result of the deployment of these new space networks is the ability to provide high-speed, low-latency Internet connections to any point on the globe. Combined with Earth observation capabilities, these new communications resources also enable real-time action to be taken in any region, including those with no equipment other than terminals. In addition, these space networks are remarkably resilient compared with terrestrial networks. Geostrategic and military considerations combine with rapidly evolving business models to explain the massive investments currently being made in this domain. However, the lack of international regulation in the field is leading to a race to occupy orbits and frequencies, which has already had serious consequences for a whole range of scientific activities. These constellations have a potentially negative impact on astronomy in the visible and infrared optical domains, as well as on radio astronomy. They also raise a major problem in terms of space congestion, with an increase in the amounts of satellite debris resulting from launches or collisions between satellites, and the possibility of reaching a phase of chain reaction collisions. In addition, from an environmental point of view, the consequences of the proliferation of launches and uncontrolled re-entries into the atmosphere are equally worrying. What’s more, the lack of regulation in the field also leads to a loss of sovereignty, since these new satellite communication networks do not comply with any of the rules that states impose on terrestrial communication networks operating on their territories. A sustainable, global solution must be found to these problems, before major and potentially irreversible damage is inflicted on the planet’s environment, geostrategic balances, democracy, and science. While the Acad´emie des Sciences considers that France and Europe need to step up their scientific and industrial actions in this field in order to benefit from the remarkable advances of these new networks, and ultimately leverage the benefits of a resilient and secure communications network, the Acad´emie also recommends working in parallel to strengthen regulation of the field with the aim of assuring sustainable access to orbital and frequency resources, as well as protection for negatively impacted fields, foremost among which are astronomy and the environment. (10.62686/3)
  DOI : 10.62686/3
• Monitoring the Convergence Speed of PDHG to Find Better Primal and Dual Step Sizes
  
  • Fercoq Olivier
  , 2024. Primal-dual algorithms for the resolution of convex-concave saddle point problems usually come with one or several step size parameters. Within the range where convergence is guaranteed, choosing well the step size can make the difference between a slow or a fast algorithm. A usual way to adaptively set step sizes is to ensure that there is a fair balance between primal and dual variable's amount of change. In this work, we show how to find even better step sizes for the primal-dual hybrid gradient. Getting inspiration from quadratic problems, we base our method on a spectral radius estimation procedure and try to minimize this spectral radius, which is directly related to the rate of convergence. Building on power iterations, we could produce spectral radius estimates that are always smaller than 1 and work also in the case of conjugate principal eigenvalues. For strongly convex quadratics, we show that our step size rule yields an algorithm as fast as inertial gradient descent. Moreover, since our spectral radius estimates only rely on residual norms, our method can be readily adapted to more general convex-concave saddle point problems. In a second part, we extend these results to a randomized version of PDHG called PURE-CD. We design a statistical test to compare observed convergence rates and decide whether a step size is better than another. Numerical experiments on least squares, sparse SVM, TV-L1 denoising and TV-L2 denoising problems support our findings.
• Knowledge Graph Extension leveraging Language Models
  
  • Zhang Yang
  • Mimouni Nada
  • Moissinac Jean-Claude Jc
  , 2024. <div><p>The knowledge graph is a structured format for integrating heterogeneous data, enabling comprehensive exploration and reasoning of data from different sources, such as the cultural heritage domain. However, knowledge graphs are typically incomplete, as they model realworld information. Creating and populating such knowledge graphs is a resource-intensive endeavour that requires significant human expertise.</p><p>Knowledge graph completion aims to use machine learning techniques to complete a knowledge graph without the need for human experts. Existing methods such as translation models can automatically predict the missing connections or entities in the knowledge graph, achieving high performance across domains. On the other hand, pre-trained language models, especially large language models, have been really successful in various tasks, showing the possibility of applying the language models in knowledge graph completion tasks.</p><p>In our work, we extend knowledge graph completion techniques to the WJoconde dataset, which is a real French heritage dataset. We exploit the power of both classical embedding models, such as the translation models, and the pre-trained language models. By using these models, we aim to minimise the manual effort required while providing enriched, contextually relevant structures for querying and exploring the heritage data. The developed technique could also be applied to other domains. In this work, we first studied the characteristics of the WJoconde dataset and proposed several steps to clean the dataset. Then, we applied the classical knowledge graph completion models, especially embedding-based translation models and bilinear models, to build baselines for the domain-specific data and discussed the difference between the common datasets and real datasets. Based on this, we constructed a smaller multimodal dataset containing knowledge graph, text description and images. We then explored the pre-trained language models to apply to the knowledge graph completion task, and developed a new pipeline using zero-shot learning with the Llama2 model on heritage data.</p><p>Our work shows the effectiveness of using LLMs, and that image data can help to overcome the shortfall of large language model evaluation by using image understanding models. We have shown that when rich text information is available, large language models can achieve high performance in knowledge graph completion, with the possibility of introducing new entities into the graph, which is not feasible when using classical models. Finally, we proposed several ways to improve our method, such as developing better prompt templates and using image data efficiently.</p></div>
• Conjunctive Queries on Probabilistic Graphs: The Limits of Approximability
  
  • Amarilli Antoine
  • van Bremen Timothy
  • Meel Kuldeep
  , 2024, 27th International Conference on Database Theory. Query evaluation over probabilistic databases is a notoriously intractable problem - not only in combined complexity, but for many natural queries in data complexity as well [Antoine Amarilli et al., 2017; Nilesh N. Dalvi and Dan Suciu, 2012]. This motivates the study of probabilistic query evaluation through the lens of approximation algorithms, and particularly of combined FPRASes, whose runtime is polynomial in both the query and instance size. In this paper, we focus on tuple-independent probabilistic databases over binary signatures, which can be equivalently viewed as probabilistic graphs. We study in which cases we can devise combined FPRASes for probabilistic query evaluation in this setting. We settle the complexity of this problem for a variety of query and instance classes, by proving both approximability and (conditional) inapproximability results. This allows us to deduce many corollaries of possible independent interest. For example, we show how the results of [Marcelo Arenas et al., 2021] on counting fixed-length strings accepted by an NFA imply the existence of an FPRAS for the two-terminal network reliability problem on directed acyclic graphs: this was an open problem until now [Rico Zenklusen and Marco Laumanns, 2011]. We also show that one cannot extend a recent result [Timothy van Bremen and Kuldeep S. Meel, 2023] that gives a combined FPRAS for self-join-free conjunctive queries of bounded hypertree width on probabilistic databases: neither the bounded-hypertree-width condition nor the self-join-freeness hypothesis can be relaxed. Finally, we complement all our inapproximability results with unconditional lower bounds, showing that DNNF provenance circuits must have at least moderately exponential size in combined complexity. (10.4230/LIPIcs.ICDT.2024.15)
  DOI : 10.4230/LIPIcs.ICDT.2024.15
• Informed Speech Self-supervised Representation Learning
  
  • Zaiem Mohamed Salah
  , 2024. Feature learning has been driving machine learning advancement with the recently proposed methods getting progressively rid of handcrafted parts within the transformations from inputs to desired labels. Self-supervised learning has emerged within this context, allowing the processing of unlabeled data towards better performance on low-labeled tasks. The first part of my doctoral work is aimed towards motivating the choices in the speech selfsupervised pipelines learning the unsupervised representations. In this thesis, I first show how conditional-independence-based scoring can be used to efficiently and optimally select pretraining tasks tailored for the best performance on a target task. The second part of my doctoral work studies the evaluation and usage of pretrained self-supervised representations. I explore, first, the robustness of current speech self-supervision benchmarks to changes in the downstream modeling choices. I propose, second, fine-tuning approaches for better efficicency and generalization. (10.70675/dc53ad72z177fz4bb4z91fbzd00576ba3f2e)
  DOI : 10.70675/dc53ad72z177fz4bb4z91fbzd00576ba3f2e
• Skyline Operators for Document Spanners
  
  • Amarilli Antoine
  • Kimelfeld Benny
  • Labbé Sébastien
  • Mengel Stefan
  , 2024, 290, pp.7:1-7:18. When extracting a relation of spans (intervals) from a text document, a common practice is to filter out tuples of the relation that are deemed dominated by others. The domination rule is defined as a partial order that varies along different systems and tasks. For example, we may state that a tuple is dominated by tuples that extend it by assigning additional attributes, or assigning larger intervals. The result of filtering the relation would then be the skyline according to this partial order. As this filtering may remove most of the extracted tuples, we study whether we can improve the performance of the extraction by compiling the domination rule into the extractor. To this aim, we introduce the skyline operator for declarative information extraction tasks expressed as document spanners. We show that this operator can be expressed via regular operations when the domination partial order can itself be expressed as a regular spanner, which covers several natural domination rules. Yet, we show that the skyline operator incurs a computational cost (under combined complexity). First, there are cases where the operator requires an exponential blowup on the number of states needed to represent the spanner as a sequential variable-set automaton. Second, the evaluation may become computationally hard. Our analysis more precisely identifies classes of domination rules for which the combined complexity is tractable or intractable. (10.4230/LIPICS.ICDT.2024.7)
  DOI : 10.4230/LIPICS.ICDT.2024.7
• Ranked Enumeration for MSO on Trees via Knowledge Compilation
  
  • Amarilli Antoine
  • Bourhis Pierre
  • Capelli Florent
  • Monet Mikaël
  , 2024, 290 (25), pp.5:1–25:18. We study the problem of enumerating the satisfying assignments for circuit classes from knowledge compilation, where assignments are ranked in a specific order. In particular, we show how this problem can be used to efficiently perform ranked enumeration of the answers to MSO queries over trees, with the order being given by a ranking function satisfying a subset-monotonicity property. Assuming that the number of variables is constant, we show that we can enumerate the satisfying assignments in ranked order for so-called multivalued circuits that are smooth, decomposable, and in negation normal form (smooth multivalued DNNF). There is no preprocessing and the enumeration delay is linear in the size of the circuit times the number of values, plus a logarithmic term in the number of assignments produced so far. If we further assume that the circuit is deterministic (smooth multivalued d-DNNF), we can achieve linear-time preprocessing in the circuit, and the delay only features the logarithmic term. (10.4230/LIPIcs.ICDT.2024.25)
  DOI : 10.4230/LIPIcs.ICDT.2024.25
• Internal methods for the generation and inpainting of images and videos
  
  • Cherel Nicolas
  , 2024. Image editing and generation are complex problems in image processing. Recently, we have seen a great leap in development by using learning-based approaches that take advantage of large image databases.In this thesis, we study internal methods i.e. methods based on a single image as a data source.This includes patch-based methods, internal learning approaches that train a neural network on a single image, and attention mechanisms that combine patches and deep networks.First, we present a contribution to single image generation with a patch-based method. This classical approach is competitive with recent network-based approaches but does not require a learning phase.Second, attention mechanisms are important for modeling long-range dependencies and are more flexible than convolutions but suffer from poor computational complexity. In fact, the complexity grows quadratically with the number of input elements making such layers unusable for high-resolution images or videos. We propose an efficient approximation based on nearest neighbor search.Finally, we look at the recent diffusion models for image and video inpainting. In the single image setting, we show how very lightweight architectures are competitive with the state-of-the-art. Our models run and train at a fraction of the computational cost of popular models.We also propose an application to video inpainting with a specific training strategy that significantly improves the results over the baseline. This strategy is particularly adapted to these one-shot models. (10.70675/c150b98az8511z4246zb69dz883db7f96d05)
  DOI : 10.70675/c150b98az8511z4246zb69dz883db7f96d05
• Digital Coherent Sensing over Deployed Fibers for Advanced Network Telemetry
  
  • Guerrier Sterenn
  • Dorize Christian
  • Pavani Henrique
  • Mardoyan Haïk
  • Awwad Élie
  • Renaudier Jérémie
  , 2024, pp.Tu2J.1. We discuss the performance of Coherent-MIMO-DFS over deployed optical networks in various configurations and address technological challenges such as adaptation to various fiber types, disturbance identification. (10.1364/OFC.2024.Tu2J.1)
  DOI : 10.1364/OFC.2024.Tu2J.1
• Experimental Disaggregation of Propagation Effects in Optical Links
  
  • Girard-Jollet Joana
  • Antona Jean-Christophe
  • Carbo Meseguer Alexis
  • Boitier Fabien
  • Ramantanis Petros
  • Rekaya Ben Othman Ghaya
  , 2024, pp.1-3. We introduce a protocol to evaluate experimentally the fiber nonlinear coefficients for intra- and inter-channel effects. We characterized a three-span transmission using highly dispersed QPSK signals, observing good agreement with the eGN model.
• A Study on Hierarchical Text Classification as a Seq2seq Task
  
  • Torba Fatos
  • Gravier Christophe
  • Laclau Charlotte
  • Kammoun Abderrhammen
  • Subercaze Julien
  , 2024. With the progress of generative neural models, Hierarchical Text Classification (HTC) can be cast as a generative task. In this case, given an input text, the model generates the sequence of predicted class labels taken from a label tree of arbitrary width and depth. Treating HTC as a generative task introduces multiple modeling choices. These choices vary from choosing the order for visiting the class tree and therefore defining the order of generating tokens, choosing either to constrain the decoding to labels that respect the previous level predictions, up to choosing the pre-trained Language Model itself. Each HTC model therefore differs from the others from an architectural standpoint, but also from the modeling choices that were made. Prior contributions lack transparent modeling choices and open implementations, hindering the assessment of whether model performance stems from architectural or modeling decisions. For these reasons, we propose with this paper an analysis of the impact of different modeling choices along with common model errors and successes for this task. This analysis is based on an open framework coming along this paper that can facilitate the development of future contributions in the field by providing datasets, metrics, error analysis toolkit and the capability to readily test various modeling choices for one given model. (10.1007/978-3-031-56063-7_20)
  DOI : 10.1007/978-3-031-56063-7_20
• EME-CNTK: Infinite Limits of Convolutional Neural Network for Urban Electromagnetic Field Exposure Reconstruction
  
  • Mallik Mohammed
  • Allaert Benjamin
  • Egea-Lopez E.
  • Gaillot D.P.
  • Wiart J.
  • Clavier L.
  IEEE Access, IEEE, 2024, 12, pp.49476-49488. Electromagnetic field (EMF) exposure has grown to be a critical concern as a consequence of the ongoing installation of fifth-generation cellular networks (5G). The lack of measurements makes it difficult to accurately assess the EMF in a specific urban area, as Spectrum cartography (SC) relies on a set of measurements recorded by spatially distributed sensors for the generation of exposure maps. However, when the spatial sampling rate is limited, significant estimation errors occur. To overcome this issue, the exposure map estimation is addressed as a missing data imputation task. We compute a convolutional neural tangent kernel (CNTK) for an infinitely wide convolutional neural network whose training dynamics can be completely described by a closed-form formula. This CNTK is employed to impute the target matrix and estimate EMF exposure from few sensors sparsely located in an urban environment. Experimental results show that the kernel, even when only sparse sensor data are available, can produce accurate estimates. It is a promising solution for exposure map reconstruction that does not require large training sets. The proposed method is compared with other deep learning approaches and Gaussian Process regression. (10.1109/ACCESS.2024.3380835)
  DOI : 10.1109/ACCESS.2024.3380835
• A Reconfigurable Programmable Logic Block for a Multi-Style Asynchronous FPGA resistant to Side-Channel Attacks
  
  • Hoogvorst Philippe
  • Guilley Sylvain
  • Chaudhuri Sumanta
  • Danger Jean-Luc
  • Beyrouthy Taha
  • Fesquet Laurent
  , 2008. Side-channel attacks are efficient attacks against cryptographic devices. They use only quantities observable from outside, such as the duration and the power consumption. Attacks against synchronous devices using electric observations are facilitated by the fact that all transitions occur simultaneously with some global clock signal. Asynchronous control remove this synchronization and therefore makes it more difficult for the attacker to insulate \emph{interesting intervals}. In addition the coding of data in an asynchronous circuit is inherently more difficult to attack. This article describes the Programmable Logic Block of an asynchronous FPGA resistant against \emph{side-channel attacks}. Additionally it can implement different styles of asynchronous control and of data representation. (10.48550/arXiv.0809.3942)
  DOI : 10.48550/arXiv.0809.3942