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TL;DR: In this paper, transmission electron microscopy observations were made on several coexisting spinel-garnet assemblies: alkremite xenolith; pyrope-rich spinel assembly deformed at 1173K, 800 MPa in a Griggs apparatus; (Mg,Fe)3(Al,Mg-Si,Si)2Si3O12 majorite-spinel assembly synthesized in a laser heated diamond anvil cell.
Abstract: In order to better identify the mineral phase which controls the rheology of the transition zone (between 410 and 660 km depth) transmission electron microscopy observations were made on several coexisting spinel-garnet assemblies: alkremite xenolith; pyrope-rich – MgO:1.1Al2O3 spinel assembly deformed at 1173K, 800 MPa in a Griggs apparatus; (Mg,Fe)3(Al,Mg,Si)2Si3O12 majorite – (Mg,Fe)2SiO4 spinel assembly synthesized in a laser heated diamond anvil cell. It was found that garnet crystals systematically remain undeformed while spinel crystals are plastically deformed. These results are in accord with the assumption that the rheology of majorite is stronger than the rheology of spinel, in the conditions of the transition zone.
17 citations
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TL;DR: In this article, a metallic bandgap material (EBG) is realized by combining 4/spl times/4 unit cells in a square geometry and excited by a microstrip line through a slot-aperture.
Abstract: A metallic electromagnetic bandgap material (EBG) is realised by combining 4/spl times/4 unit cells in a square geometry and excited by a microstrip line through a slot-aperture. It is shown that this structure is a radiating one, called an EBG patch, resonating at a lower frequency than the plain patch showing the same dimensions. An analytical model for the wavenumber of the EBG material facilitates the design of the EBG patch.
17 citations
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26 May 2013TL;DR: This paper designs more sophisticated non-local TV constraints which are derived from the structure tensor and shows that the proposed epigraphical projection method leads to significant improvements in terms of convergence speed over existing numerical solutions.
Abstract: TV-like constraints/regularizations are useful tools in variational methods for multicomponent image restoration. In this paper, we design more sophisticated non-local TV constraints which are derived from the structure tensor. The proposed approach allows us to measure the non-local variations, jointly for the different components, through various l1,p matrix norms with p ≥ 1. The related convex constrained optimization problems are solved through a novel epigraphical projection method. This formulation can be efficiently implemented thanks to the flexibility offered by recent primal-dual proximal algorithms. Experiments carried out for color images demonstrate the interest of considering a Non-Local Structure Tensor TV and show that the proposed epigraphical projection method leads to significant improvements in terms of convergence speed over existing numerical solutions.
17 citations
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22 Sep 2004TL;DR: Recent results about polynomial matrices in several indeterminates are used to prove the invertibility of the mixing process and an iterative blind source separation method is extended to the multi-dimensional case and it is shown that it still applies if the source spectra vanish on an interval.
Abstract: The paper deals with blind source separation of images. The model which is adopted here is a convolutive multi-dimensional one. Recent results about polynomial matrices in several indeterminates are used to prove the invertibility of the mixing process. We then extend an iterative blind source separation method to the multi-dimensional case and show that it still applies if the source spectra vanish on an interval. Based on experimental observations we then discuss problems arising when we want to separate natural images: the sources are non i.i.d. and have a band limited spectrum; a scalar filtering indeterminacy thus remains after separation.
17 citations
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TL;DR: In this article, a cell-centered collocated finite volume scheme for incompressible flows is presented and analyzed, and the convergence of the approximate solution toward the solution to the continuous problem is proven, provided, in particular, that the approximation of the mass balance flux is second order accurate.
Abstract: We present and analyse in this paper a novel cell-centered collocated finite volume scheme for incompressible flows. Its definition involves a partition of the set of control volumes; each element of this partition is called a cluster and consists in a few neighbouring control volumes. Under a simple geometrical assumption for the clusters, we obtain that the pair of discrete spaces associating the classical cell-centered approximation for the velocities and cluster-wide constant pressures is inf-sup stable; in addition, we prove that a stabilization involving pressure jumps only across the internal edges of the clusters yields a stable scheme with the usual collocated discretization (i.e. , in particular, with control-volume-wide constant pressures), for the Stokes and the Navier-Stokes problem. An analysis of this stabilized scheme yields the existence of the discrete solution (and uniqueness for the Stokes problem). The convergence of the approximate solution toward the solution to the continuous problem as the mesh size tends to zero is proven, provided, in particular, that the approximation of the mass balance flux is second order accurate; this condition imposes some geometrical conditions on the mesh. Under the same assumption, an error analysis is provided for the Stokes problem: it yields first-order estimates in energy norms. Numerical experiments confirm the theory and show, in addition, a second order convergence for the velocity in a discrete L2 norm.
17 citations
Authors
Showing all 831 results
Name | H-index | Papers | Citations |
---|---|---|---|
Dapeng Yu | 94 | 745 | 33613 |
Daniel Azoulay | 78 | 510 | 23979 |
Mehmet A. Oturan | 77 | 261 | 22682 |
Alfred O. Hero | 73 | 899 | 29258 |
Nihal Oturan | 64 | 174 | 12092 |
Jean-Christophe Pesquet | 50 | 364 | 13264 |
Eric D. van Hullebusch | 50 | 265 | 9030 |
Christian Soize | 48 | 529 | 9932 |
Maxime Crochemore | 47 | 314 | 9836 |
Jean-Yves Thibon | 42 | 191 | 6398 |
Marie-France Sagot | 41 | 191 | 5972 |
François Farges | 41 | 111 | 6349 |
Laurent Najman | 40 | 233 | 9238 |
Renaud Keriven | 39 | 108 | 6330 |
Robert Eymard | 39 | 171 | 6964 |