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Curiosity-driven exploration: Diversity of mechanisms and functions
No full textInternational audienceIntrinsically motivated information-seeking, also called curiositydriven exploration, is widely believed to be a key ingredient for autonomous learning in the real world. Such forms of spontaneous exploration have been studied in multiple independent lines of computational research, producing a diverse range of algorithmic models that capture different aspects of these processes. These algorithms resolve some of the limitations of neurocognitive theories by formally describing computational functions and algorithmic implementations of intrinsically motivated learning. Moreover, they reveal a high diversity of effective forms of intrinsically motivated information-seeking that can be characterized along different mechanistic and functional dimensions. This chapter aims at reviewing different classes of algorithms and highlighting several important dimensions of variation among them. Identifying these dimensions provides means for structuring a comprehensive taxonomy of approaches. We believe this exercise to be useful in working towards a general computational account of information-seeking. Such an account should facilitate the proposition of new hypotheses about informationseeking in humans and complement the existing psychological theory of curiosity
Économie de la puissance : quel impact de l’intelligence artificielle
No full textTable Ronde 3 : Les avancées technologiques au sein de la bataille multi- domaine : multiplicatrices de puissances ou nouveau talon d’Achille des armées connectées ?International audienc
Mechanical behavior of a chromium coating on a zirconium alloy substrate at room temperature
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Vapor-liquid equilibria of α-tocopherol in transportation fuels surrogates: An experimental and modeling study
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Multidirectional sweeping preconditioners with non-overlapping checkerboard domain decomposition for Helmholtz problems
No full textInternational audienceThis paper explores a family of generalized sweeping preconditionners for Helmholtz problems with non-overlapping checkerboard partition of the computational domain. The domain decomposition procedure relies on high-order transmission conditions and cross-point treatments, which cannot scale without an efficient preconditioning technique when the number of subdomains increases. With the proposed approach, existing sweeping preconditioners, such as the symmetric Gauss-Seidel and parallel double sweep preconditioners, can be applied to checkerboard partitions with different sweeping directions (e.g. horizontal and diagonal). Several directions can be combined thanks to the flexible version of GMRES, allowing for the rapid transfer of information in the different zones of the computational domain, then accelerating the convergence of the final iterative solution procedure. Several two-dimensional finite element results are proposed to study and to compare the sweeping preconditioners, and to illustrate the performance on cases of increasing complexity
Simulation of ductile tearing during a full size test using a non local Gurson-Tvergaard-Needleman (GTN) model
No full textInternational audienceDuctile tearing of a full size precracked pipe is experimentally investigated. In order to model and interpret the test, the pipe material is characterized using smooth and notched tensile bars and precracked C(T) specimens. This experimental database is used to fit the parameters of the non local Gurson-Tvergaard-Needleman (GTN) proposed in [? ? ]. The model is used in finite element simulations using specific elements allowing for the control of strain/damage localization as well as volumetric locking. Mesh size independence is checked on notched tensile bars. The model is then able to represent the early stages of crack propagation in the pipe. In particular, experimentally observed crack branching is reproduced, whereas this appeared much more difficult to obtain using a local GTN model
Identification of the Damage Scenarios under Cyclic Loading of a Coated 300M Steel by Infrared Thermography Measurements
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Sub-laser-cycle control of relativistic plasma mirrors
No full textLetter - Open AccessInternational audienceWe present measurements of high-order harmonics and relativistic electrons emitted into the vacuum from a plasma mirror driven by temporally-shaped ultra-intense laser waveforms, produced by collinearly combining the main laser field with its second harmonic. We experimentally show how these observables are influenced by the phase delay between these two frequencies at the attosecond timescale, and relate these observations to the underlying physics through an advanced analysis of 1D/2D Particle-In-Cell simulations. These results demonstrate that sub-cycle shaping of the driving laser field provides fine control on the properties of the relativistic electron bunches responsible for harmonic and particle emission from plasma mirrors