Hal - Université Grenoble Alpes
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Formal Verification of Borrow-Checking by Local Commutation Diagrams
No full textInternational audienceThe Rust programming language provides a safe alternative to C and C++ for system programming. In particular, it achieves memory safety with an ownership-based typing discipline, providing a notion of borrows as a restriction on aliasable pointers. The discipline of borrows is statically enforced by a component of the compiler called the borrow-checker. In their article published at the ICFP conference in 2024, Ho, Fromherz and Protzenko prove that LLBC, a borrow-centric model of Rust, can be equipped with a symbolic semantics that plays the role of a borrow-checker. They also prove that LLBC is a sound model with respect to an operational semantics over a standard memory model à la CompCert.In this article, we initiate the formalization of this work in the Rocq proof assistant. In particular, we found a flaw in the proofs of some of their fundamental lemmas. We repair their methodology using techniques from rewriting theory. We finally present the current state of our formalization, and how we use a rewriting system to automate proofs.</p
Wadsley-Roth FeNb11O29 as negative electrode material for lithium solid-state batteries
No full textInternational audienceFeNb 11 O 29 and Li 6 PS 5 Cl but revealed an interfacial degradation, with a resistive Li 2 S/oxide-rich interface, consistent with impedance growth. These findings highlight the critical role of microstructural and interfacial optimisation in the electrode composites and establish FeNb 11 O 29 as a promising candidate for high-rate solidstate batteries.</div
Environmental Assessment for Upscaling: an LCA-based eco-design process for design teams
No full textInternational audienceThe upscaling of technologies is a socio-technical phenomenon covering technological development and deployment in society to meet societal imperatives (e.g. sustainability). It is characterized by five archetypes, each encompassing specific design practices and models referring to a great variety of consequences on industrial systems. However, these upscaling archetypes are not addressed in current eco-design practices, and even less so in a unified way. This research paper, based on a literature review on LCA, upscaling, and eco-design, presents a new LCA-based design process, titled Environmental Assessment for Upscaling (EAU). This methodological contribution constitutes upscaling environmental assessment guidelines for design team stakeholders (e.g. technical expert, lifecycle expert, company manager). Its originality is to propose a structure favouring the emergence of an accurate consideration of the environmental aspects of the upscaling with an aggregated approach of the upscaling archetype modelling. The EAU process clarifies the main points of interest in the LCA practices related to upscaling assessment from various LCA communities. This methodology follows six necessary steps, and relies on original and interlinked categories of upscaling parameters, enabling design teams to consider the upscaling as a whole during the eco-design process. Four additional resources to guide design team stakeholder collaboration are presented in parallel, with a focus on lifecycle engineering. Finally, the operationalization of the EAU process is discussed considering the LCA standard as a vector of integration in companies. Reinforcing the EAU process’ use could help design teams manage sustainability consistently and support the necessary ecological shifts at the company level
Equations of motion of the mass centers in a scalar theory of gravity with a preferred frame
No full textThe theory considered interprets gravity as a pressure force. Thus, the scalar gravitational field defines the gravity acceleration field. However, it also determines the relation between the flat "background metric" and a curved "physical metric". Here we derive the equations of motion of the mass centers of a system of weakly gravitating bodies in the second version of that theory. We use the framework which was built and used for the first version. Namely, we use an asymptotic scheme of post-Newtonian (PN) approximation to derive the local (field) PN equations, and by integration inside the bodies we deduce from those local equations the equations of motion of the mass centers, using also an asymptotic framework for the good separation between the different bodies
Passivity Preservation in Interconnections of Linear Cone Complementarity Systems with State Jumps
No full textInternational audienceThis article is largely concerned with generic interconnections of a class of passive nonsmooth nonlinear dynamical systems, namely linear cone complementarity systems (LCCS). We stipulate that each subsystem admits a positive definite storage function that characterizes the passivity of an underlying nonsmooth mapping. We provide algebraic criteria in terms of these individual storage functions to find the storage function which guarantees passivity of the overall interconnected system. State jumps in the interconnections are studied in detail. Examples from dynamic feedback control, switching DAEs and nonsmooth circuits are included as an illustration of the theoretical developments
Surface ice texture mapping of Planpincieux glacier reveals spatial mechanical heterogeneities
No full textInternational audienceCrystallographic textures or Crystal Preferred Orientations (CPO) of glacier ice significantly influence its mechanical behavior by transferring mechanical anisotropy from the single-crystal scale to the macroscopic scale. However, their spatial variability and impact on fluidity remain poorly constrained in temperate glaciers. This study presents a detailed mapping of surface crystallographic textures on the Planpincieux Glacier (Mont Blanc Massif, Italy), combining field measurements, surface velocity data, and numerical modeling to assess mechanical heterogeneities. Six sampling zones were analyzed using an Automatic Ice Texture Analyser (AITA), revealing distinct crystallographic texture patterns linked to local strain configurations and boundary conditions. Weak crystallographic textures in zones near the glacier margins and crevasse areas suggest limited viscous deformation, while stronger crystallographic textures indicate deformation under various shear boundary conditions with impact of dynamic recrystallization. The resulting textures are associated with a fluidity enhancement factor reaching up to 2.3 and a fluidity anisotropy up to 5.4. These findings underscore the importance of integrating texture impact into glacier flow models, particularly in temperate environments where recrystallization and complex stress regimes prevail
Domaine public global : une ferme sans fermage (obs. sous CAA Versailles, 6 nov. 2025, n° 23VE02793, A. c./ Domaine national de Chambord)
No full textInternational audienc
Nature-based solutions for water management: Pluridisciplinary state-of-the-art and research needs
No full textInternational audienceNature-based Solutions (NbS) offer a way to preserve, manage and restore ecosystems so as to better meet today's societal challenges, by combining benefits for society and the environment, including biodiversity. They are a response to current climate change-related challenges for water management. However, various barriers exist to the implementation of NbS, such as a lack of appropriation of the concept, as well as needs for knowledge and know-how. Focusing on societal challenges linked to water, we highlight the importance of implementing pluridisciplinary and transdisciplinary projects when trying to implement NbS projects. This requires new approaches in research, practice, and governance. This discussion allows identifying levers for a widespread use of NbS for water management
A semi-automated sensitivity-based approach for simplifying marine biogeochemical models for targeted applications: A case study with the Eco3M-MED model
No full textInternational audienceMarine biogeochemical models are being increasingly used to support scenario-based analyses of climate change and ecosystem dynamics. However, their high structural complexity and large parameter space often limit computational efficiency, interpretability, and adaptability in applications requiring the exploration of many scenarios. To address these issues, we propose a Semi-Automated Iterative Simplification (SAIS) approach that integrates local sensitivity analysis with model mechanistic guidance and Kling-Gupta Efficiency (KGE) metrics to evaluate each simplification step. Using the marine biogeochemical model Eco3M-MED as an example, we specified three objectives for model simplification: (1) fidelity of state variables, (2) fidelity of marine ecosystem indicators, and (3) applicability for coupling with higher trophic level models. For each objective, we assessed model sensitivity to parameters and applied the SAIS approach to simplify the model, and obtained three simplified models. KGE-based fidelity evaluations are used to validate each final simplified model against the reference model. The results show that computational time can be reduced by up to approximately 30% without compromising the model's mechanistic foundation. Overall, this method offers a flexible and scalable approach for generating simplified versions of complex biogeochemical models, suitable for applications in regional marine ecosystem assessments, climate scenario explorations, and model coupling frameworks
Diffusion-based Frameworks for Unsupervised Speech Enhancement
No full textThis paper addresses unsupervised diffusion-based single-channel speech enhancement (SE). Prior work in this direction combines a score-based diffusion model trained on clean speech with a Gaussian noise model whose covariance is structured by non-negative matrix factorization (NMF). This combination is used within an iterative expectation–maximization (EM) scheme, in which a diffusion-based posterior-sampling E-step estimates the clean speech. We first revisit this framework and propose to explicitly model both speech and acoustic noise as latent variables, jointly sampling them in the E-step instead of sampling speech alone as in previous approaches. We then introduce a new unsupervised SE framework that replaces the NMF noise prior with a diffusion-based noise model, learned jointly with the speech prior in a single conditional score model. Within this framework, we derive two variants: one that implicitly accounts for noise and one that explicitly treats noise as a latent variable. Experiments on WSJ0–QUT and VoiceBank–DEMAND show that explicit noise modeling systematically improves SE performance for both NMF-based and diffusion-based noise priors. Under matched conditions, the diffusion-based noise model attains the best overall quality and intelligibility among unsupervised methods, while under mismatched conditions the proposed NMF-based explicit-noise framework is more robust and suffers less degradation than several supervised baselines. Our code will be publicly available at https://github.com/jeaneudesAyilo/enudiffuse