École normale supérieure de Cachan

About: École normale supérieure de Cachan is a education organization based out in Cachan, Île-de-France, France. It is known for research contribution in the topics: Decidability & Finite element method. The organization has 2717 authors who have published 5585 publications receiving 175925 citations.

Motivating Human–Agent Interaction: Transferring Insights from Behavioral Marketing to Interface Design

Abstract: The understanding of consumer interaction with online EC Websites is one of the big current challenges for online marketers. The present paper investigates what drives and impedes Net customers to interact with a marketer's websites and, more specifically, with decision support interface systems (DSISs) employed in these sites to assist users when shopping or searching for high-involvement consumer goods. DSIS are considered as a predecessor or partially already integrator of more elaborated agent systems that may be used in future EC environments. It is shown that the design of today's DSISs is sub-optimal for both marketers and consumers, because it fails to motivate user interaction. One reason for this might be that little effort has been made to transfer the insights from consumer behavior to the design of EC user interfaces. The current paper aims to address this gap by proposing a number of new DSIS design principles, all of which are based on insights from traditional marketing search- and perceived risk theory. The main contribution of this paper is that it proposes a design approach for EC Websites that intuitively “makes the user model available to the user” [Shneiderman and Maes, 36].

Two scale damage model and related numerical issues for thermo-mechanical High Cycle Fatigue

Abstract: On the idea that fatigue damage is localized at the microscopic scale, a scale smaller than the mesoscopic one of the Representative Volume Element (RVE), a three-dimensional two scale damage model has been proposed for High Cycle Fatigue applications. It is extended here to anisothermal cases and then to thermo-mechanical fatigue. The modeling consists in the micromechanics analysis of a weak micro-inclusion subjected to plasticity and damage embedded in an elastic meso-element (the RVE of continuum mechanics). The consideration of plasticity coupled with damage equations at microscale, altogether with Eshelby–Kroner localization law, allows to compute the value of microscopic damage up to failure for any kind of loading, 1D or 3D, cyclic or random, isothermal or anisothermal, mechanical, thermal or thermo-mechanical. A robust numerical scheme is proposed in order to make the computations fast. A post-processor for damage and fatigue (DAMAGE_2005) has been developed. It applies to complex thermo-mechanical loadings. Examples of the representation by the two scale damage model of physical phenomena related to High Cycle Fatigue are given such as the mean stress effect, the non-linear accumulation of damage. Examples of thermal and thermo-mechanical fatigue as well as complex applications on real size testing structure subjected to thermo-mechanical fatigue are detailed.

Repulsive contact interactions make jammed particulate systems inherently nonharmonic.

Abstract: Many jammed particulate systems, such as granular and colloidal materials, interact via repulsive contact forces. We find that these systems possess no harmonic regime in the large system limit (N→∞) for all compressions Δϕ studied, and at jamming onset Δϕ→0 for all N. We perform fixed energy simulations following perturbations with amplitude δ along eigendirections of the dynamical matrix. The fluctuations abruptly spread to all modes for δ≈δ(c) (where a single contact breaks) in contrast to linear and weakly nonlinear behavior. For δ > δ(c), all discrete modes disappear into a continuous frequency band. scales with 1/N and Δϕ, which limits harmonic behavior to only overcompressed systems. The density of vibrational modes deviates strongly from that predicted from the dynamical matrix when the system enters the nonharmonic regime, which significantly affects its mechanical and transport properties.

Differential Evolution for Many-Particle Adaptive Quantum Metrology

Abstract: We devise powerful algorithms based on differential evolution for adaptive many-particle quantum metrology. Our new approach delivers adaptive quantum metrology policies for feedback control that are orders-of-magnitude more efficient and surpass the few-dozen-particle limitation arising in methods based on particle-swarm optimization. We apply our method to the binary-decision-tree model for quantum-enhanced phase estimation as well as to a new problem: a decision tree for adaptive estimation of the unknown bias of a quantum coin in a quantum walk and show how this latter case can be realized experimentally.