Conservatoire national des arts et métiers

About: Conservatoire national des arts et métiers is a education organization based out in Paris, France. It is known for research contribution in the topics: Population & Orthogonal frequency-division multiplexing. The organization has 3573 authors who have published 7127 publications receiving 141430 citations. The organization is also known as: CNAM & Conservatoire des arts et métiers.

A Unified Beam Finite Element Model for Extension and Shear Piezoelectric Actuation Mechanisms

Abstract: This paper presents a finite element model for adaptive sandwich beams to deal with either extension or shear actuation mechanism The former corresponds to an elastic core sandwiched beam between two transversely polarized active surface layers; whereas, the latter consists of an axially polarized core, sandwiched between two elastic surface layers For both configurations, an electric field is applied through thickness of the piezoelectric layers The mechanical model is based on Bernoulli-Euler theory for the surface layers and Timoshenko beam theory for the core It uses three variables, through-thickness constant deflection, and the mean and relative axial displacements of the core's upper and lower surfaces Augmented by the bending rotation, these are the only nodal degrees of freedom of the proposed two-node adaptive sandwich beam finite element The piezoelectric effect is handled through modification of the constitutive equation, when induced electric potential is taken into account, and additio

L'alchimie de la compétence

Abstract: L’entreprise s’efforce aujourd’hui de transformer des actifs et des ressources en profit a travers des competences specifiques. Elle met ainsi en œuvre une nouvelle alchimie de la competence. Apportant des definitions claires et operationnelles de ce concept, souvent utilise de facon confuse dans la litterature en gestion, l’auteur propose ici un modele de la competence articule autour de trois dimensions qui relevent de la connaissance (les savoirs), des pratiques (les savoir-faire) et des attitudes (le savoir etre). Et il inclut dans ce modele non seulement les processus de management mais aussi la structure organisationnelle, la decision strategique et l’identite.

A Novel Filter-Bank Multicarrier Scheme to Mitigate the Intrinsic Interference: Application to MIMO Systems

Abstract: Filter-bank multicarrier (FBMC) transmission system was proposed as an alternative approach to orthogonal frequency division multiplexing (OFDM) system since it has a higher spectral efficiency. One of the characteristics of FBMC is that the demodulated transmitted symbols are accompanied by interference terms caused by the neighboring transmitted data in time-frequency domain. The presence of this interference is an issue for some multiple-input multiple-output (MIMO) schemes and until today their combination with FBMC remains an open problem. We can cite, among these techniques, the Alamouti scheme and the maximum likelihood detection (MLD) with spatial multiplexing (SM). In this paper, we shall propose a new FBMC scheme and transmission strategy in order to avoid this interference term. This proposed scheme (called FFT-FBMC) transforms the FBMC system into an equivalent system formulated as OFDM regardless of some residual interference. Thus, any OFDM transmission technique can be performed straightforwardly to the proposed FBMC scheme with a corresponding complexity growth compared to the classical FBMC. First, we will develop the FFT-FBMC in the case of single-input single-output (SISO) configuration. Then, we extend its application to SM-MIMO configuration with MLD and Alamouti coding scheme. Simulation results show that FFT-FBMC can almost reach the OFDM performance, but it remains slightly outperformed by OFDM.

Determination of the fine structure constant based on bloch oscillations of ultracold atoms in a vertical optical lattice

Abstract: We report an accurate measurement of the recoil velocity of Rb atoms based on Bloch oscillations in a vertical accelerated optical lattice. We transfer about 900 recoil momenta with an efficiency of 99.97 % per recoil. A set of 72 measurements of the recoil velocity, each one with a relative uncertainty of about 33 ppb in 20 min integration time, leads to a determination of the fine structure constant alpha with a statistical relative uncertainty of 4.4 ppb. The detailed analysis of the different systematic errors yields to a relative uncertainty of 6.7 ppb. The deduced value of 1/alpha is 137.03599878(91).