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Haptic Rendering Using Reality-Based Force Profiles in Surgical Simulation
No full textInternational audienceThis paper presents a novel method for simplifying kinesthetic haptic rendering of complex contact interactions in arthroscopic surgery training simulators using reality-based force profiles. We demonstrate continuous kinesthetic feedback for applications to arthroscopic knee portal creation and diagnostic meniscus examination. This involves measuring characteristic force profiles in ex vivo experiments, simulator implementation in SOFA, and performing user validation experiments. When comparing the method with linear-elastic-based haptic feedback for meniscus stiffness discrimination, novices had difference thresholds of 1.80 MPa (linear-elastic) and 1.47 MPa (reality-based), while experts showed thresholds of 0.99 MPa and 1.39 MPa, respectively, indicating finer sensitivity among experts. Experts also used significantly less force (p<0.05) and had shorter decision times (p<0.05) than novices across both methods, indicating construct validity. Although kinesthetic feedback was verified with ex vivo experiments for portal creation, user validation was here inconclusive due to minor inconsistencies in the integration of visual and haptic feedback. Limitations include triggering material removal via instrument penetration instead of haptic force limits, as well as omitting contact vibrations. The method gives only a minor reduction in computation speed. Examples are available on GitHub
Le travail plutôt que l’école d’ingénieurs ? Les formes masculines et féminines d’adhésion à l’apprentissage ingénieur
No full textInternational audienceCommunication lors de la Table ronde IV : Les produits de l’alternance. Ce que l’alternance fait aux apprentis (1), animée par Barbara Duc (HEFP, Université de Lausanne) le deuxième jou
The accountability of ethnographers: the views of Paolo Virno
No full textFNEGE 4, ABS 2International audiencePurpose - Ethnography produces accounts; the critical reflection of accounts produces accountability. Ethnography requires accountability if meaningful conclusions and/or observations are to be made. Accountability requires ethnography if is to address lived experiences. Virno argues that the principles of “languaging” make ethnographies and accountability possible. This papers aims to describe an instance of the circularity of accountability and use this to explore Virno’s insights. Doing this helps us to see the connections between accountability and ethnography, and reflect on the nature of these interconnections. Design/methodology/approach - Inspired by Paulo Virno’s philosophy, the authors assert that an ethnographer typically produces an account of a chosen “Other” in which this “Other” is held to account. But at the same time, the ethnographer needs to be held to account by the very same “Other” and by the “Other” of the (research) community. Furthermore, ethnographers are accountable to themselves. All these moments of accountability can endlessly circle, as responsibilization of the researchers by their Other(s) continues. For ethnography to function, this must be tamed as a (research) account ultimately has to be produced for an academic project to be considered complete. Drawing on Virno’s principle of the “negation of the negation” by the “katechon,” by the “katechon,” the authors propose a potentially valuable intervention that would enable ethnography – and by extension, ethnographers – to prosper. Findings - The authors apply Virno’s philosophical reflections to propose a positive feedback cycle between ethnography and accountability. Virno’s ideation centers on two key concepts: (i) the multitude of social relatedness and (ii) the ontology of the languaging of individuation. Hereby, a positive circle of causality between ethnography and accountability can be realized, whereby the authors can respect but also break the causal circle(s) of ethnography and accountability. This might be achieved via a reflection on Virno’s concept of the “katechon.” Originality/value - The authors illuminate the accountability–ethnography dynamic, providing an illustration of the circularity of ethnography and accountability and showing how Virno provides us with tools to help us deal with it. Hence, ultimately, the paper focuses on the accountability as ethnographers
An integration model for the mapping of BPMN to smart contract: MCQ case study
No full textInternational audienceBlockchain technology and BPMN (Business Process Model and Notation) hold great promise for revolutionizing a wide range of industries by improving transparency, security, and efficiency. In this paper, we propose an integration model for the systematic translation of any BPMN process into a Blockchain with smart contracts. Essentially, our approach aims to support smart contract practitioners working on complex business cases or those new to Solidity by simplifying the language and providing a clear, user-friendly path to translate business processes into effective Solidity code. Our model was applied in a real-world case study to streamline multiple-choice question (MCQ) creation and management in education. Finally, this paper discusses the potential impact of this integrated approach on educational assessment practices and suggests avenues for future research and development
Has AlphaFold 3 achieved success for RNA?
No full textInternational audiencePredicting the 3D structure of RNA is a significant challenge despite ongoing advancements in the field. Although AlphaFold has successfully addressed this problem for proteins, RNA structure prediction raises difficulties due to the fundamental differences between proteins and RNA, which hinder its direct adaptation. The latest release of AlphaFold , AlphaFold 3, has broadened its scope to include multiple different molecules such as DNA, ligands and RNA. While the AlphaFold 3 article discussed the results for the last CASP-RNA data set, the scope of its performance and the limitations for RNA are unclear. In this article, we provide a comprehensive analysis of the performance of AlphaFold 3 in the prediction of 3D structures of RNA. Through an extensive benchmark over five different test sets, we discuss the performance and limitations of AlphaFold 3. We also compare its performance with ten existing state-of-the-art ab initio , template-based and deep-learning approaches. Our results are freely available on the EvryRNA platform at https://evryrna.ibisc.univ-evry.fr/evryrna/alphafold3/
Hoping for the best while preparing for the worst in the face of uncertainty: a new type of incomplete preferences
No full textWe propose and axiomatize a new model of incomplete preferences under uncertainty, which we call hope-and-prepare preferences. Act f is considered more desirable than act g when, and only when, both an optimistic evaluation, computed as the welfare level attained in a best-case scenario, and a pessimistic one, computed as the welfare level attained in a worst-case scenario, rank f above g. Our comparison criterion involves multiple priors, as best and worst cases are determined among sets of probability distributions, and is, generically, less conservative than Bewley preferences and twofold multi-prior preferences, the two ambiguity models that are closest to ours
L'indétermination juridique des institutions du contrôle bancaire en France (1941-1965)
No full textInternational audienceCommunication lors de la session 4 "Les institutions du marché des capitaux et du monde entrepreneurial" lors des sessions parallèles "Les institutions dans les domaines de recherche de l'IDHE.S" (mercredi 8 janvier 2025 ; 9h30 - 11h00
Event-triggered joint adaptive high-gain observer design for delayed output-sampled nonlinear systems with unknown parameters and output injection
No full textInternational audienceThis study presents a novel event-triggered joint adaptive high-gain observer design for delayed output-sampled nonlinear systems with output injection. These systems are characterized by the presence of unknown parameters that influence both the state and output equations. The major difficulty in designing the observer lies in the interplay between event-triggered mechanism, output injection, and time-varying delays. Additionally, the non-affine nature of the parameter's entry into the system states equation further complicates the design. To address these challenges, a new adaptive law for unknown parameter estimation is developed under delay measurement. A novel non-Zeno dynamic event-triggered mechanism coupled with a closed-loop output predictor is proposed. The resulting observer exhibits two main features: the first one provides an input-to-state stable property, and the second one is the establishment of a theoretical condition for the inter-event time of the proposed dynamic event-triggered mechanism. The effectiveness of the designed observer is demonstrated through numerical simulations and performance comparisons with previous works
Transcriptomic response of the picoalga Pelagomonas calceolata to nitrogen availability: new insights into cyanate lyase function
No full textInternational audienceAbstract. Cyanate (OCN − ) is an organic nitrogen compound found in aquatic environments potentially involved in phytoplankton growth. Given the prevalence and activity of cyanate lyase genes in eukaryotic microalgae, cyanate has been suggested as an alternative source of nitrogen in the environment. However, the conditions under which cyanate lyase is expressed and the actual capacity of microalgae to assimilate cyanate remain largely underexplored. Here, we studied the nitrogen metabolism in the cosmopolitan open-ocean picoalga Pelagomonas calceolata (Pelagophyceae and Stramenopiles) in environmental metatranscriptomes and transcriptomes from culture experiments under different nitrogen sources and concentrations. We observed that cyanate lyase is upregulated in nitrate-poor oceanic regions, suggesting that cyanate is an important molecule contributing to the persistence of P. calceolata in oligotrophic environments. Non-axenic cultures of P. calceolata were capable of growing on various nitrogen sources, including nitrate, urea, and cyanate, but not ammonium. RNA sequencing of these cultures revealed that cyanate lyase was downregulated in the presence of cyanate, indicating that this gene is not involved in the catabolism of extracellular cyanate to ammonia. Based on environmental data sets and laboratory experiments, we propose that cyanate lyase is important in nitrate-poor environments to generate ammonia from cyanate produced by endogenous nitrogenous compound recycling rather than being used to metabolize imported extracellular cyanate as an alternative nitrogen source.Importance. Vast oceanic regions are nutrient-poor, yet several microalgae thrive in these environments. While various acclimation strategies to these conditions have been discovered in a limited number of model microalgae, many important lineages remain understudied. Investigating nitrogen metabolism across different microalga lineages is crucial for understanding ecosystem functioning in low-nitrate areas, especially in the context of global ocean warming. This study describes the nitrogen metabolism of Pelagomonas calceolata , an abundant ochrophyte in temperate and tropical oceans. By utilizing both global scale in situ metatranscriptomes and laboratory-based transcriptomics, we uncover how P. calceolata adapts to low-nitrate conditions. Our findings reveal that P. calceolata can metabolize various nitrogenous compounds and relies on cyanate lyase to recycle endogenous nitrogen in low-nitrate conditions. This result paves the way for future investigations into the significance of cyanate metabolism within oceanic trophic webs
Bridging the Gap Between Real and Virtual Touch : Multisensory Avatars for Enhanced Training in Virtual Reality
No full textInternational audienceThis position paper presents our ongoing PhD work exploring the integration of interpersonal haptic interactions into immersive VR training systems for first responders. The research focuses on enhancing user engagement, emotional resilience, and decision-making in high-stress scenarios by leveraging advanced haptic technologies, such as vibrotactile feedback and electromuscular stimulation. The primary goal is to model and simulate haptic interactions, such as touch sensations perceived by individuals in the real world, enhancing the realism of virtual training. This paper details the research objectives and the ongoing work and highlights the critical gaps this work aims to address in thecurrent VR training landscape