Demodulation of Spatial Carrier Images: Performance Analysis of Several Algorithms Using a Single Image

Optical full-field techniques have a great importance in modern experimental mechanics. Even if they are reasonably spread among the university laboratories, their diffusion in industrial companies remains very narrow for several reasons, especially a lack of metrological performance assessment. A full-field measurement can be characterized by its resolution, bias, measuring range, and by a specific quantity, the spatial resolution. The present paper proposes an original procedure to estimate in one single step the resolution, bias and spatial resolution for a given operator (decoding algorithms such as image correlation, low-pass filters, derivation tools …). This procedure is based on the construction of a particular multi-frequential field, and a Bode diagram representation of the results. This analysis is applied to various phase demodulating algorithms suited to estimate in-plane displacements.     

Un Theoreme De Finitude Dans Le Spectre Automorphe Pour Les Formes Interieures De GLn Sur Un Corps Global

A proof is given to show that for an inner form of GL_n overa global field of zero characteristic, there exist only a finitenumber of automorphic representations with fixed local factor(up to equivalence) at almost every place. What is new in comparisonto earlier work (see A. I. Badulescu and P. Broussous, ‘Unthéorème de finitude’, Compositio Math.132 (2002) 177–190) is the case when the local factorsare not fixed at the infinite places, as well as the statementof the result for the automorphic spectrum, rather than thecuspidal one. 2000 Mathematics Subject Classification 11F70.     

Orthogonalité des caractères pour GLn sur un corps local de caractéristique non nulle

We prove the orthogonality relations for characters of GL ⁿ (F) with F a local field of positive characteristic. Using this, we establish a Jacquet-Langlands correspondence with the group of invertible elements of a central division algebra of dimension n ² over F, and the transfer of orbital integrals between these two groups. Received: 16 February 1999     

A Procedure for Accurate One-Dimensional Strain Measurement Using the Grid Method

This paper deals with the accurate calculation of strain using the grid method. The strain field is first directly deduced from the fringe pattern without calculating the displacement field. This procedure is validated with two numerical examples. Two types of experiment are then carried out: a translation and a tensile test. It is observed that some additional fictitious strains appear in both cases. They are due to two main reasons which interact with each other: the grid defects and the displacement of the grid lines during testing. A suitable procedure is proposed to cancel out these fictitious strains. This procedure is successfully applied in two cases of fringe patterns.     

Giant magnetoresistive coatings using thermionic vacuum arc technology

Giant magnetoresistive (GMR) coatings on silicon, glass and Kapton were prepared by simultaneous thermionic vacuum arc (TVA) discharges in high vacuum conditions. The magnetic metal or alloy (Fe, Co, Ni, Permalloy) together with the noble non magnetic metal were deposited on substrates having different positions relative to the discharges. Local magnetic interactions and Fe-phase composition were obtained by Mössbauer spectroscopy whereas the magnetoresistance effects were measured by a dc method using a four-point configuration with perpendicular to plane magnetic fields up to 0.8 T. The surface morphology of the coatings was characterized by atomic force microscopy (AFM) in contact mode.     

Correspondance de Jacquet-Langlands pour les corps locaux de caractéristique non nulle

In this article we prove the Jacquet-Langlands local correspondence in non-zero characteristic. Let F be a local field of non-zero charactersitic and G′ an inner form of GL_n(F); then, following [17], we prove relations between the representation theory of G′ and the representation theory of an inner form of GL_n(L), where L is a local field of zero characteristic close to F. The proof of the Jacquet-Langlands correspondence between G′ and GL_n(F) is done using the above results and ideas from the proof by Deligne, Kazhdan and Vignéras [10] of the zero characteristic case. We also get the following, already known in zero characteristic: orthogonality relations for G′, inequality involving conductor and level for representations of G′ and finiteness for automorphic cuspidal representations with fixed component at almost every place for an inner form of GL_n over a global field of non-zero characteristic.     

Global Jacquet–Langlands correspondence,multiplicity one and classification of automorphic representations

In this paper we generalize the local Jacquet-Langlands correspondence to all unitary irreducible representations. We prove the global Jacquet-Langlands correspondence in characteristic zero. As consequences we obtain the multiplicity one and strong multiplicity one Theorems for inner forms of GL(n) as well as a classification of the residual spectrum and automorphic representations in analogy with results proved by Mœglin–Waldspurger and Jacquet–Shalika for GL(n).     

Un théorème de finitude (A Theorem of Finitude)

We prove that, for an inner form of GL _n , the number of classes of cuspidal automorphic representations with fixed central character and fixed factor at almost every place is finite. We also prove, in the local situation, relations between the level and the -factor of an irreducible smooth representation.