Publications

2025

• Private Data Analysis over Encrypted Databases : Mixing Functional Encryption with Computational Differential Privacy
  
  • Alborch Escobar Ferran
  , 2025. In our current digitalized society, data is ruling the world. But as it is most of the time related to individuals, its exploitation should respect the privacy of the latter. This issue has raised the differential privacy paradigm, which permits to protect individuals when querying databases containing data about them. But with the emergence of cloud computing, it is becoming increasingly necessary to also consider the confidentiality of "on-cloud'' storage confidentiality of such vast databases, using encryption techniques. This thesis studies how to provide both privacy and confidentiality of such outsourced databases by mixing two primitives: computational differential privacy and functional encryption. First, we study the relationship between computational differential privacy and functional encryption for randomized functions in a generic way. We analyze the privacy of the setting where a malicious analyst may access the encrypted data stored in a server, either by corrupting or breaching it, and prove that a secure randomized functional encryption scheme supporting the appropriate family of functions guarantees the computational differential privacy of the system. Second, we construct efficient randomized functional encryption schemes for certain useful families of functions, and we prove them secure in the standard model under well-known assumptions. The families of functions considered are linear functions, used for example in counting queries, histograms and linear regressions, and quadratic functions, used for example in quadratic regressions and hypothesis testing. The schemes built are then used together with the first result to construct encrypted databases for their corresponding family of queries. Finally, we implement both randomized functional encryption schemes to analyze their efficiency. This shows that our constructions are practical for databases with up to 1 000 000 entries in the case of linear queries and databases with up to 10 000 database entries in the case of quadratic queries. (10.70675/7fd3987az3c65z4befz98f3zc4201f35a247)
  DOI : 10.70675/7fd3987az3c65z4befz98f3zc4201f35a247
• Laser Guard: Efficiently Detecting Laser-Based Physical Adversarial Attacks in Autonomous Driving
  
  • Chi Lijun
  • Msahli Mounira
  IEEE Access, IEEE, 2025, 13, pp.35219-35229. <div><p>The fast development of deep learning (DL) enables even resource-constrained devices to tackle complex artificial intelligence (AI) tasks, especially those related to environment perception in autonomous driving systems (ADS). However, AI models deployed in the real world are exposed to the threats of adversarial examples (AE). One specific type of physical attack utilizes laser beams or spots planted on images rather than crafted pixel-level perturbations to manipulate the victim deep neural networks (DNN) prediction. These attacks easily mislead traffic sign recognition and object detection in ADS. Laser-based adversarial attacks are cognitively stealthy but visually conspicuous, invalidating the previous defenses designed for digital attacks. This study considers two state-of-the-art (SOTA) laser-based attacks and establishes a benchmark comprising thousands of AEs. Such AEs have distinct pattern features, significant occupation, high contrast, and low variance. Based on the observation, a lightweight detection framework, Laser Guard, is proposed. Specifically, preprocessing methods are used to approximate the laserperturbed areas, followed by a statistics-based strategy to determine abnormalities in the given samples. This framework can be applied in a plug-and-play manner with DNNs in intelligent vehicles. Extensive experimental results show that the framework can effectively filter out about 70-75% of laser-based street sign AEs, and extends well to other objects, successfully filtering out 80%. The detection latency of objects AEs is marginal, with the average detection time for laser spots being approximately 24 ms, and for laser beams, it is around 57 ms.</p><p>INDEX TERMS Deep learning, adversarial attacks, detection-based defense, laser-based attacks, preprocessing.</p></div> (10.1109/ACCESS.2025.3540653)
  DOI : 10.1109/ACCESS.2025.3540653
• Ambiguity and Invariance in Machine Listening
  
  • Perera David
  , 2025. Machine listening is a growing field with applications in security (audio surveillance), health (sound-based diagnosis), transportation (autonomous driving), manufacturing (predictive maintenance), and bioacoustics (ecosystem tracking). It addresses tasks like sound event detection, sound source localization, and speech separation. This thesis tackles two key challenges: first, the lack of training data in this field, which hinders deep neural networks, typically most effective using large data sets; second, the ambiguity in many tasks, where input-target relations are non-deterministic, which challenges the use of single-prediction models. To address the data shortage, we apply semi supervised invariance-based learning, which penalizes model variations near training data and enforces invariance, enhancing data efficiency and generalization capabilities. Using sound event detection as a case study, we investigate the impact of different data augmentations, their intensity, and the layer of the neural network used for penalization.To tackle ambiguity, we use Multiple Choice Learning (MCL), a framework that trains a multi-head neural network to produce a small set of plausible and diverse predictions, using a competitive training scheme that promotes the specialization of the predictions in different regions of the prediction space. We investigate the efficiency of MCL for machine listening, addressing two key challenges. First, MCL suffers from hypothesis collapse, where some network heads stop being updated by gradient descent. We mitigate this by introducing annealing, which ensures that collapsed heads receive gradients and guides the optimization toward better solutions. Second, we extend MCL’s discrete predictions to create a non-sparse estimator of the target probability distribution. We find that usual approaches fail to converge to the true target distribution when the number of predictions grows large. We identify the cause of this issue—kernel density leakage between heads—and propose kernel truncation as a solution, proving that it guarantees the convergence of the estimators. These methods are shown to improve performance in speech separation tasks. (10.70675/164092fdz865cz4fe7za2a9z2f88f6f38360)
  DOI : 10.70675/164092fdz865cz4fe7za2a9z2f88f6f38360
• POLSAR2POLSAR: A SEMI-SUPERVISED DESPECKLING ALGORITHM FOR POLARIMETRIC SAR IMAGES
  
  • Mendes Cristiano Ulondu
  • Dalsasso Emanuele
  • Zhang Yi
  • Denis Loïc
  • Tupin Florence
  ISPRS Journal of Photogrammetry and Remote Sensing, Elsevier, 2025, 220 (0924-2716), pp.783-798. <div><p>Polarimetric Synthetic Aperture Radar (PolSAR) imagery is a valuable tool for Earth observation. This imaging technique finds wide application in various fields, including agriculture, forestry, geology, and disaster monitoring. However, due to the inherent presence of speckle noise, filtering is often necessary to improve the interpretability and reliability of PolSAR data. The effectiveness of a speckle filter is measured by its ability to attenuate fluctuations without introducing artifacts or degrading spatial and polarimetric information. Recent advancements in this domain leverage the power of deep learning. These approaches adopt a supervised learning strategy, which requires a large amount of speckle-free images that are costly to produce. In contrast, this paper presents PolSAR2PolSAR, a semi-supervised learning strategy that only requires, from the sensor under consideration, pairs of noisy images of the same location and acquired in the same configuration (same incidence angle and mode as during the revisit of the satellite on its orbit). Our approach applies to a wide range of sensors. Experiments on Radarsat-2 and RCM data demonstrate the capacity of the proposed method to effectively reduce speckle noise and retrieve fine details. The code of the trained models is made freely available at https://gitlab.telecom-paris.fr/ring/polsar2polsar. The repository additionally contains a model fine-tuned on SLC PolSAR images from NASA's UAVSAR sensor.</p></div>
• Graph-based Moving Object Segmentation for underwater videos using semi-supervised learning
  
  • Kapoor Meghna
  • Prummel Wieke
  • Giraldo Jhony
  • Subudhi Badri Narayan
  • Zakharova Anastasia
  • Bouwmans Thierry
  • Bansal Ankur
  Computer Vision and Image Understanding, Elsevier, 2025, 252, pp.104290. Moving object segmentation (MOS) using passive underwater image processing is an important technology for monitoring marine habitats. It aids marine biologists studying biological oceanography and the associated fields of chemical, physical, and geological oceanography to understand marine organisms. Dynamic backgrounds due to marine organisms like algae and seaweed, and improper illumination of the environment pose challenges in detecting moving objects in the scene. Previous graph-learning methods have shown promising results in MOS, but are mostly limited to terrestrial surface videos such as traffic video surveillance. Traditional object modeling fails in underwater scenes, due to fish shape and color degradation in motion and the lack of extensive underwater datasets for deep-learning models. Therefore, we propose a semi-supervised graph-learning approach (GraphMOS-U) to segment moving objects in underwater environments. Additionally, existing datasets were consolidated to form the proposed Teleost Fish Classification Dataset, specifically designed for fish classification tasks in complex environments to avoid unseen scenes, ensuring the replication of the transfer learning process on a ResNet-50 backbone. GraphMOS-U uses a six-step approach with transfer learning using Mask R-CNN and a ResNet-50 backbone for instance segmentation, followed by feature extraction using optical flow, visual saliency, and texture. After concatenating these features, a k-NN Graph is constructed, and graph node classification is applied to label objects as foreground or background. The foreground nodes are used to reconstruct the segmentation map of the moving object from the scene. Quantitative and qualitative experiments demonstrate that GraphMOS-U outperforms state-of-the-art algorithms, accurately detecting moving objects while preserving fine details. The proposed method enables the use of graph-based MOS algorithms in underwater scenes. (10.1016/j.cviu.2025.104290)
  DOI : 10.1016/j.cviu.2025.104290
• LayerFold: A Python library to reduce the depth of neural networks
  
  • Pilo Giommaria
  • Hezbri Nour
  • Pereira E Ferreira André
  • Quétu Victor
  • Tartaglione Enzo
  SoftwareX, Elsevier, 2025, 29, pp.102030. Large-scale models are the backbone of Computer Vision and Natural Language Processing, and their generalizability allows for transfer learning and deployment in different scenarios. However, their large size means that reducing their computational and memory demands remains a challenge. Recent research proposes to achieve “layer collapse”, a condition where multiple layers can be combined due to the collapse of non-linearities to linear operators. While this is an important discovery, most studies remain theoretical, often replacing non-linearities with simple identity functions and not providing a real implementation of the more compact architecture. Our contribution is LayerFold, a library that studies and implements the merging of collapsed layers. We address typical cases, from fully connected to convolutional layers, discussing constraints and prospective challenges. Our tests on edge devices reveal that merely reducing network depth does not always result in faster computation, even when GPU-equipped. This work raises important warnings and opens the door to further advances in efficient model deployment. (10.1016/j.softx.2024.102030)
  DOI : 10.1016/j.softx.2024.102030
• Learning on graphs : from algorithms to socio-technical analyses on AI
  
  • Delarue Simon
  , 2025. This thesis addresses the dual challenge of advancing Artificial Intelligence (AI) methods while critically assessing their societal impact. With AI technologies now embedded in high-stake decision sectors like healthcare and justice, their growing influence demands thorough examination, reflected in emerging international regulations such as the AI Act in Europe. To address these challenges, this work leverages attributed-graph based methods and advocates for a shift from performance-focused AI models to approaches that also prioritise scalability, simplicity, and explainability.The first part of this thesis develops a toolkit of attributed graph-based methods and algorithms aimed at enhancing AI learning techniques. It includes a software contribution that leverages the sparsity of complex networks to reduce computational costs. Additionally, it introduces non-neural graph models for node classification and link predictions tasks, showing how these methods can outperform advanced neural networks while being more computationally efficient. Lastly, it presents a novel pattern mining algorithm that generates concise, human-readable summaries of large networks. Together, these contributions highlight the potential of these approaches to provide efficient and interpretable solutions to AI's technical challenges.The second part adopts an interdisciplinary approach to study AI as a socio-technical system. By framing AI as an ecosystem influenced by various stakeholders and societal concerns, it uses graph-based models to analyse interactions and tensions related to explainability, ethics, and environmental impact. A user study explores the influence of graph-based explanations on user perceptions of AI recommendations, while the building and analysis of a corpus of AI ethics charters and manifestos quantifies the roles of key actors in AI governance. A final study reveals that environmental concerns in AI are primarily framed technically, highlighting the need for a broader approach to the ecological implications of digitalisation. (10.70675/9b959076z9900z480ez90b4z48f18740c846)
  DOI : 10.70675/9b959076z9900z480ez90b4z48f18740c846
• Strong Converse for Classical-Quantum Degraded Broadcast Channels
  
  • Cheng Hao-Chung
  • Datta Nilanjana
  • Rouzé Cambyse
  , 2019. We consider the transmission of classical information through a degraded broadcast channel, whose outputs are two quantum systems, with the state of one being a degraded version of the other. Yard et al. proved that the capacity region of such a channel is contained in a region characterized by certain entropic quantities. We prove that this region satisfies the strong converse property, that is, the maximal probability of error incurred in transmitting information at rates lying outside this region converges to one exponentially in the number of uses of the channel. In establishing this result, we prove a second-order Fano-type inequality, which might be of independent interest. A powerful analytical tool which we employ in our proofs is the tensorization property of the quantum reverse hypercontractivity for the quantum depolarizing semigroup. (10.48550/arXiv.1905.00874)
  DOI : 10.48550/arXiv.1905.00874
• GraphRAG: Leveraging Graph-Based Efficiency to Minimize Hallucinations in LLM-Driven RAG for Finance Data
  
  • Barry Mariam
  • Caillaut Gaëtan
  • Halftermeyer Pierre
  • Qader Raheel
  • Mouayad Mehdi
  • Cariolaro Dimitri
  • Deit Fabrice Le
  • Gesnouin Joseph
  , 2025. This study explores the integration of graphbased methods into Retrieval-Augmented Generation (RAG) systems to enhance efficiency, reduce hallucinations, and improve explainability, with a particular focus on financial and regulatory document retrieval. We propose two strategies-FactRAG and HybridRAG-which leverage knowledge graphs to improve RAG performance. Experiments conducted using Finance Bench, a benchmark for AI in finance, demonstrate that these approaches achieve a 6% reduction in hallucinations and an 80% decrease in token usage compared to conventional RAG methods. Furthermore, we evaluate HybridRAG by comparing the Digital Operational Resilience Act (DORA) from the European Union with the Federal Financial Institutions Examination Council (FFIEC) guidelines from the United States. The results reveal a significant improvement in computational efficiency, reducing contradiction detection complexity from O(n 2 ) to O(k •n)-where n is the number of chunks-and a remarkable 734-fold decrease in token consumption. Graph-based retrieval methods can improve the efficiency and cost-effectiveness of large language model (LLM) applications, though their performance and token usage depend on the dataset, knowledge graph design, and retrieval task.
• Rapid thermalization of dissipative many-body dynamics of commuting Hamiltonians
  
  • Kochanowski Jan
  • Alhambra Alvaro
  • Capel Angela
  • Rouzé Cambyse
  , 2024. Quantum systems typically reach thermal equilibrium rather quickly when coupled to a thermal environment. The usual way of bounding the speed of this process is by estimating the spectral gap of the dissipative generator. However the gap, by itself, does not always yield a reasonable estimate for the thermalization time in many-body systems: without further structure, a uniform lower bound on it only constrains the thermalization time to grow polynomially with system size. Here, instead, we show that for a large class of geometrically-2-local models of Davies generators with commuting Hamiltonians, the thermalization time is much shorter than one would naïvely estimate from the gap: at most logarithmic in the system size. This yields the so-called rapid mixing of dissipative dynamics. The result is particularly relevant for 1D systems, for which we prove rapid thermalization with a system size independent decay rate only from a positive gap in the generator. We also prove that systems in hypercubic lattices of any dimension, and exponential graphs, such as trees, have rapid mixing at high enough temperatures. We do this by introducing a novel notion of clustering which we call "strong local indistinguishability" based on a max-relative entropy, and then proving that it implies a lower bound on the modified logarithmic Sobolev inequality (MLSI) for nearest neighbour commuting models. This has consequences for the rate of thermalization towards Gibbs states, and also for their relevant Wasserstein distances and transportation cost inequalities. Along the way, we show that several measures of decay of correlations on Gibbs states of commuting Hamiltonians are equivalent, a result of independent interest. At the technical level, we also show a direct relation between properties of Davies and Schmidt dynamics, that allows to transfer results of thermalization between both. (10.48550/arXiv.2404.16780)
  DOI : 10.48550/arXiv.2404.16780
• Quasi-optimal sampling from Gibbs states via non-commutative optimal transport metrics
  
  • Capel Ángela
  • Gondolf Paul
  • Kochanowski Jan
  • Rouzé Cambyse
  , 2024. We study the problem of sampling from and preparing quantum Gibbs states of local commuting Hamiltonians on hypercubic lattices of arbitrary dimension. We prove that any such Gibbs state which satisfies a clustering condition that we coin decay of matrix-valued quantum conditional mutual information (MCMI) can be quasi-optimally prepared on a quantum computer. We do this by controlling the mixing time of the corresponding Davies evolution in a normalized quantum Wasserstein distance of order one. To the best of our knowledge, this is the first time that such a non-commutative transport metric has been used in the study of quantum dynamics, and the first time quasi-rapid mixing is implied by solely an explicit clustering condition. Our result is based on a weak approximate tensorization and a weak modified logarithmic Sobolev inequality for such systems, as well as a new general weak transport cost inequality. If we furthermore assume a constraint on the local gap of the thermalizing dynamics, we obtain rapid mixing in trace distance for interactions beyond the range of two, thereby extending the state-of-the-art results that only cover the nearest neighbor case. We conclude by showing that systems that admit effective local Hamiltonians, like quantum CSS codes at high temperature, satisfy this MCMI decay and can thus be efficiently prepared and sampled from. (10.48550/arXiv.2412.01732)
  DOI : 10.48550/arXiv.2412.01732
• STanH : Parametric Quantization for Variable Rate Learned Image Compression
  
  • Presta Alberto
  • Tartaglione Enzo
  • Fiandrotti Attilio
  • Grangetto Marco
  IEEE Transactions on Image Processing, Institute of Electrical and Electronics Engineers, 2025, 34, pp.639-651. In end-to-end learned image compression, encoder and decoder are jointly trained to minimize a R+λD cost function, where λ controls the trade-off between rate of the quantized latent representation and image quality. Unfortunately, a distinct encoder-decoder pair with millions of parameters must be trained for each λ , hence the need to switch encoders and to store multiple encoders and decoders on the user device for every target rate. This paper proposes to exploit a differentiable quantizer designed around a parametric sum of hyperbolic tangents, called STanH, that relaxes the step-wise quantization function. STanH is implemented as a differentiable activation layer with learnable quantization parameters that can be plugged into a pre-trained fixed rate model and refined to achieve different target bitrates. Experimental results show that our method enables variable rate coding with comparable efficiency to the state-of-the-art, yet with significant savings in terms of ease of deployment, training time, and storage costs. (10.1109/TIP.2025.3527883)
  DOI : 10.1109/TIP.2025.3527883
• Zero-Knowledge Proofs of Quantumness
  
  • Phan Duong Hieu
  • Wen Weiqiang
  • Yan Xingyu
  • Zheng Jinwei
  IACR Communications in Cryptology, International Association for Cryptologic Research (IACR), 2025, 1 (4), pp.1-19. With the rapid development of quantum computers, proofs of quantumness have recently become an interesting and intriguing research direction. However, in all current schemes for proofs of quantumness, quantum provers almost invariably face the risk of being maliciously exploited by classical verifiers. In fact, through malicious strategies in interaction with quantum provers, classical verifiers could solve some instances of hard problems that arise from the specific scheme in use. In other words, malicious verifiers can break some schemes (that quantum provers are not aware of) through interaction with quantum provers. All this is due to the lack of formalization that prevents malicious verifiers from extracting useful information in proofs of quantumness. To address this issue, we formalize zero-knowledge proofs of quantumness. Intuitively, the zero-knowledge property necessitates that the information gained by the classical verifier from interactions with the quantum prover should not surpass what can be simulated using a simulated classical prover interacting with the same verifier. As a result, the new zero-knowledge notion can prevent any malicious verifier from exploiting quantum advantage. Interestingly, we find that the classical zero-knowledge proof is sufficient to compile some existing proofs of quantumness schemes into zero-knowledge proofs of quantumness schemes. Due to some technical reason, it appears to be more general to require zero-knowledge proof on the verifier side instead of the prover side. Intuitively, this helps to regulate the verifier's behavior from malicious to be honest-but-curious. As a result, both parties will play not only one role in the proofs of quantumness but also the dual role in the classical zero-knowledge proof. Specifically, the two principle proofs of quantumness schemes: Shor's factoring-based scheme and learning with errors-based scheme in [Brakerski et al, FOCS, 2018], can be transformed into zero-knowledge proofs of quantumness by requiring an extractable non-interactive zero-knowledge argument on the verifier side. Notably, the zero-knowledge proofs of quantumness can be viewed as an enhanced security notion for proofs of quantumness. To prevent malicious verifiers from exploiting the quantum device's capabilities or knowledge, it is advisable to transition existing proofs of quantumness schemes to this framework whenever feasible. (10.62056/ayiv4fe-3)
  DOI : 10.62056/ayiv4fe-3
• Masked Computation of the Floor Function and Its Application to the FALCON Signature
  
  • Berthet Pierre-Augustin
  • Paillet Justine
  • Tavernier Cédric
  • Colombier Brice
  • Bossuet Lilian
  IACR Communications in Cryptology, International Association for Cryptologic Research (IACR), 2025, 1 (4), pp.1-23. FALCON is a signature selected for standardisation of the new Post-Quantum Cryptography (PQC) primitives by the National Institute of Standards and Technology (NIST). However, it remains a challenge to define efficient countermeasures against side-channel attacks (SCA) for this algorithm. FALCON is a lattice-based signature that relies on rational numbers, which is unusual in the cryptography field. Although recent work proposed a solution to mask the addition and the multiplication, some roadblocks remain, most noticeably, how to protect the floor function. In this work, we propose to complete the first existing tests of hardening FALCON against SCA. We perform the mathematical proofs of our methods as well as formal security proofs in the probing model by ensuring Multiple Input Multiple Output Strong Non-Interference (MIMO-SNI) security. We provide performances on a laptop computer of our gadgets as well as of a complete masked FALCON. We notice significant overhead in doing so and discuss the deployability of our method in a real-world context. (10.62056/ay73zl7s)
  DOI : 10.62056/ay73zl7s
• A Circus of Circuits: Connections Between Decision Diagrams, Circuits, and Automata
  
  • Amarilli Antoine
  • Arenas Marcelo
  • Choi Yoojung
  • Monet Mikaël
  • Broeck Guy van Den
  • Wang Benjie
  , 2024. This document is an introduction to two related formalisms to define Boolean functions: binary decision diagrams, and Boolean circuits. It presents these formalisms and several of their variants studied in the setting of knowledge compilation. Last, it explains how these formalisms can be connected to the notions of automata over words and trees.
• Edge-Minimum Walk of Modular Length in Polynomial Time
  
  • Amarilli Antoine
  • Groz Benoit
  • Wein Nicole
  , 2025, 325, pp.5:1-5:23. We study the problem of finding, in a directed graph, an st-walk of length r mod q which is edge-minimum, i.e., uses the smallest number of distinct edges. Despite the vast literature on paths and cycles with modularity constraints, to the best of our knowledge we are the first to study this problem. Our main result is a polynomial-time algorithm that solves this task when r and q are constants. We also show how our proof technique gives an algorithm to solve a generalization of the well-known Directed Steiner Network problem, in which connections between endpoint pairs are required to satisfy modularity constraints on their length. Our algorithm is polynomial when the number of endpoint pairs and the modularity constraints on the pairs are constants. (10.4230/LIPIcs.ITCS.2025.5)
  DOI : 10.4230/LIPIcs.ITCS.2025.5
• Survey of Results on the ModPath and ModCycle Problems
  
  • Amarilli Antoine
  , 2024. This note summarizes the state of what is known about the tractability of the problem ModPath, which asks if an input undirected graph contains a simple st-path whose length satisfies modulo constraints. We also consider the problem ModCycle, which asks for the existence of a simple cycle subject to such constraints. We also discuss the status of these problems on directed graphs, and on restricted classes of graphs. We explain connections to the problem variant asking for a constant vertex-disjoint number of such paths or cycles, and discuss links to other related work.
• Somewhat homomorphic encryption based on random codes
  
  • Aguilar-Melchor Carlos
  • Dyseryn Victor
  • Gaborit Philippe
  Designs, Codes and Cryptography, Springer Verlag, 2025, 93 (6), pp.1645-1669. We present a secret-key encryption scheme based on random rank metric ideal linear codes with a simple decryption circuit. It supports unlimited homomorphic additions and plaintext multiplications (i.e. the homomorphic multiplication of a clear plaintext with a ciphertext) as well as a fixed arbitrary number of homomorphic multiplications. We study a candidate bootstrapping algorithm that requires no multiplication but additions and plaintext multiplications only. This latter operation is therefore very efficient in our scheme, whereas bootstrapping is usually the main reason which penalizes the performance of other fully homomorphic encryption schemes. However, the security reduction of our scheme restricts the number of independent ciphertexts that can be published. In particular, this prevents to securely evaluate the bootstrapping algorithm as the number of ciphertexts in the key switching material is too large. Our scheme is nonetheless the first somewhat homomorphic encryption scheme based on random ideal codes and a first step towards full homomorphism. Random ideal codes give stronger security guarantees as opposed to existing constructions based on highly structured codes. We give concrete parameters for our scheme that shows that it achieves competitive sizes and performance, with a key size of 3.7 kB and a ciphertext size of 0.9 kB when a single multiplication is allowed. (10.1007/s10623-024-01555-y)
  DOI : 10.1007/s10623-024-01555-y
• Functional analysis of multivariate max-stable distributions
  
  • Costacèque-Cecchi Bruno
  • Decreusefond Laurent
  , 2025. <div><p>We study the connections existing between max-infinitely divisible distributions and Poisson processes from the point of view of functional analysis. More precisely, we derive functional identities for the former by using well-known results of Poisson stochastic analysis. We also introduce a family of Markov semigroups whose stationary measures are the so-called multivariate max-stable distributions. Their generators thus provide a functional characterization of extreme valued distributions in any dimension. Additionally, we give a few functional identities associated to those semi-groups, namely a Poincaré identity and commutation relations. Finally, we present a stochastic process whose semigroup corresponds to the one we introduced and that can be expressed using extremal stochastic integrals.</p></div>
• Small Yet Configurable: Unveiling Null Variability in Software
  
  • Tërnava Xhevahire
  • Randrianaina Georges Aaron
  • Lesoil Luc
  • Acher Mathieu
  , 2025. Many small-scale software systems, that is, with limited codebase or binary size, are widely used in everyday tasks, yet their configurability remains largely unexplored. At the same time, studies on modern software systems show a trend toward increasing configurability, alongside growing interest in building immutable, specialized, and reproducible software. In this paper, we present the first empirical study on the extent of configurability in small-scale software systems. By analyzing 108 programs from GNU coreutils, we show that even small programs can exhibit significant compile-time and run-time variability, with up to 76 options per program. Then, there is a high correlation (0.78) between run-time variability and codebase size. Furthermore, an analysis of the 20 smallest programs across 85 releases reveals that variability tends to increase over time, primarily due to the added compile-time variability. This suggests that shifting options between run-time and compile-time, removing unnecessary run-time variability, or resolving compile-time variability early, can help reduce codebase complexity and size. We also introduce, for the first time, the concept of null-variable software system, one with no configurability beyond mandatory features. Our findings show that high configurability is not exclusive to largescale systems and that reducing unnecessary variability can lead to lightweight, smaller, and more maintainable software. We hope this effort contributes to designing new software by understanding how to balance its configurability with codebase size.
• Invertibility of functionals of the Poisson process and applications
  
  • Coutin Laure
  • Decreusefond Laurent
  The Annals of Probability, Institute of Mathematical Statistics, 2025, 53 (5). Following previous investigations by Üstünel [22] about the invertibility of some transformations on the Wiener space, we find some entropic conditions under which a random change of time is invertible on the Poisson space. As a consequence, we provide a new construction of Hawkes processes. We also establish a new variational representation of the entropy. (10.1214/24-AOP1748)
  DOI : 10.1214/24-AOP1748
• Integrating Multi-Level Mixed-Criticality into MCTS for Robust Resource Management
  
  • Cordeiro Franco
  • Tardieu Samuel
  • Pautet Laurent
  Leibniz Transactions on Embedded Systems, European Design and Automation Association (EDAA) \ EMbedded Systems Special Interest Group (EMSIG) and Schloss Dagstuhl -- Leibniz-Zentrum für Informatik GmbH, Dagstuhl Publishing., 2025, 2 (10), pp.Article No. 1, pp. 1:1–1:23. Managing actions with uncertain resource costs is a complex challenge, particularly in autonomous robot mission planning. Robots are often assigned multiple objectives with varying criticality levels, ranging from catastrophic to minor impacts, where failures can significantly affect system safety. Uncertainties in worst-case costs of resources, such as energy and operating time - the time it takes to carry out an action - further complicate mission planning and execution. Monte Carlo Tree Search (MCTS) is a powerful tool for online planning, yet it struggles to account for uncertainty in worst-case cost estimations. Optimistic estimates risk resource shortages, while pessimistic ones lead to inefficient allocation. The Mixed-Criticality (MC) approach, originally developed for real-time systems to schedule critical tasks by allocating processing resources under Worst-Case Execution Time (WCET) uncertainty, provides a framework of rules, models and design principles. We claim this framework can be adapted to autonomous robot mission planning, where critical objectives are met through analogous allocation of different kinds of resources such as energy and operating time despite uncertainties. We propose enhancing MCTS with MC principles to handle uncertainty in worst-case costs across multiple resources and criticality of objectives. High-critical objectives must always be completed, regardless of resource constraints, while low-critical objectives operate flexibly, consuming resources within optimistic estimates when possible or being discarded when resources become scarce. This ensures efficient resource reallocation and prioritization of high-critical objectives. To implement this, we present (MC)²TS, a novel variant of MCTS that integrates MC principles for dynamic resource management. It supports more than two criticality levels to ensure that the most critical components meet the most stringent safety and reliability requirements, while also enabling robust resource management. By enabling replanning and mode changes, (MC)²TS improves MCTS’s efficiency and enhances MC systems’ adaptability to both degrading and improving resource conditions. We evaluate (MC)²TS in an active perception scenario, where a drone retrieves data from distributed sensors under unpredictable environmental conditions. (MC)²TS outperforms MCTS by achieving more objectives, adapting plans when costs drop. It explores more objective sequences, minimizes oversizing, and enhances efficiency. Balancing safety and performance, it monitors robot battery, mission and objective resource constraints such as deadlines. Its robustness ensures low-critical objectives do not compromise high-critical objectives, making it a reliable solution for complex systems characterized by uncertain resource costs and critical objectives. (10.4230/LITES.10.2.1)
  DOI : 10.4230/LITES.10.2.1
• POT Python Optimal Transport
  
  • Flamary Rémi
  • Vincent-Cuaz Cédric
  • Courty Nicolas
  • Gramfort Alexandre
  • Kachaiev Oleksii
  • Quang Tran Huy
  • David Laurène
  • Bonet Clément
  • Cassereau Nathan
  • Gnassounou Theo
  • Tanguy Eloi
  • Delon Julie
  • Collas Antoine
  • Mazelet Sonia
  • Chapel Laetitia
  • Kerdoncuff Tanguy
  • Yu Xizheng
  • Feickert Matthew
  • Krzakala Paul
  • Liu Tianlin
  • Fernandes Montesuma Eduardo
  , 2025. (10.5281/ZENODO.17161062)
  DOI : 10.5281/ZENODO.17161062
• Learning and certification of local time-dependent quantum dynamics and noise
  
  • França Daniel Stilck
  • Möbus Tim
  • Rouzé Cambyse
  • Werner Albert
  , 2025. Hamiltonian learning protocols are essential tools to benchmark quantum computers and simulators. Yet rigorous methods for time-dependent Hamiltonians and Lindbladians remain scarce despite their wide use. We close this gap by learning the time-dependent evolution of a locally interacting $n$-qubit system on a graph of effective dimension $D$ using only preparation of product Pauli eigenstates, evolution under the time-dependent generator for given times, and measurements in product Pauli bases. We assume the time-dependent parameters are well approximated by functions in a known space of dimension $m$ admitting stable interpolation, e.g. by polynomials. Our protocol outputs functions approximating these coefficients to accuracy $ε$ on an interval with success probability $1-δ$, requiring only $O\big(ε^{-2}poly(m)\log(nδ^{-1})\big)$ samples and $poly(n,m)$ pre/postprocessing. Importantly, the scaling in $m$ is polynomial, whereas naive extensions of previous methods scale exponentially. The method estimates time derivatives of observable expectations via interpolation, yielding well-conditioned linear systems for the generator's coefficients. The main difficulty in the time-dependent setting is to evaluate these coefficients at finite times while preserving a controlled link between derivatives and dynamical parameters. Our innovation is to combine Lieb-Robinson bounds, process shadows, and semidefinite programs to recover the coefficients efficiently at constant times. Along the way, we extend state-of-the-art Lieb-Robinson bounds on general graphs to time-dependent, dissipative dynamics, a contribution of independent interest. These results provide a scalable tool to verify state-preparation procedures (e.g. adiabatic protocols) and characterize time-dependent noise in quantum devices.
• Certifying and learning quantum Ising Hamiltonians
  
  • Bluhm Andreas
  • Caro Matthias
  • Gutiérrez Francisco Escudero
  • Oufkir Aadil
  • Rouzé Cambyse
  , 2025. In this work, we study the problems of certifying and learning quantum Ising Hamiltonians. Our main contributions are as follows: Certification of Ising Hamiltonians. We show that certifying an Ising Hamiltonian in normalized Frobenius norm via access to its time-evolution operator requires only $\widetilde O(1/\varepsilon)$ time evolution. This matches the Heisenberg-scaling lower bound of $Ω(1/\varepsilon)$ up to logarithmic factors. To our knowledge, this is the first nearly-optimal algorithm for testing a Hamiltonian property. A key ingredient in our analysis is the Bonami Lemma from Fourier analysis. Learning Ising Gibbs states. We design an algorithm for learning Ising Gibbs states in trace norm that is sample-efficient in all parameters. In contrast, previous approaches learned the underlying Hamiltonian (which implies learning the Gibbs state) but suffered from exponential sample complexity in the inverse temperature. Certification of Ising Gibbs states. We give an algorithm for certifying Ising Gibbs states in trace norm that is both sample and time-efficient, thereby solving a question posed by Anshu (Harvard Data Science Review, 2022). Finally, we extend our results on learning and certification of Gibbs states to general $k$-local Hamiltonians for any constant $k$.