A non parametric linear feature extraction approach to texture classification

A non parametric approach to linear feature extraction is presented . The theoretical background is introduced with a new derivation of the equation that gives the best scalar extractor according to the Patrick-Fischer distance [17] . The main characteristics of the implementation are given. The application of the method to the classification of some binary synthetic textures with a natural visual aspect [15] leads to results better than those based on the Fisher discriminant analysis [7] .On présente une approche non paramétrique de l'extraction linéaire de caractéristiques et son application à la classification de textures. Le cadre théorique de l'étude est rappelé et on donne une nouvelle présentation de l'équation de l'extracteur optimal de caractéristiques selon la distance de Patrick-Fischer [17] . Les grandes lignes de la mise en oeuvre de cette méthode sont présentées . La classification de textures synthétiques binaires ayant un aspect visuel naturel [15] est ensuite abordée ; sur les exemples étudiés, on constate que la méthode proposée est meilleure, en terme de taux de bonne classification, que le classifieur basé sur l'analyse discriminante de Fisher [7]

An optical mechanism for aberration of starlight

We present a physical-optics based theory of the physical mechanism for aberration of starlight. We apply non-relativistic and relativistic theories for wavefront image formation and include the effects of optically transmitting media within the sensor. We show that the sensors imaging properties combined with finite velocity of light fully accounts for aberration. That is, the influence of the moving sensor on the incident wavefront from the star fully explains aberration. Our treatment differs from all previous derivations because we include wavefront-imaging physics within the sensor model. Our predictions match Earth-sensor based measurements, but differ at larger sensor speeds from predictions of the special relativistic-based theory. While experimental uncertainty resulting from the low Earth-orbital velocity prevents experimental confirmation of the special relativistic model of aberration, we find that Earth-based sensors containing refractive optical media could experimentally differentiate between these competing descriptions and, in addition, yield an independent test of time dilation. We derive and present the details of such an experiment

Deux méthodes de comparaison d'images pour l'identification d'objets à partir de données prospectives

Cette étude aborde le problème de l'identification d'objets mobiles à partir de données délivrées par un senseur prospectif dont la conception est actuellement en cours. Le but est d'estimer la faisabilité d'une telle identification à l'aide d'outils disponibles à ce jour en reconnaissance des formes. On présente dans ce papier la réalisation complète d'une chaîne de simulation, comprenant à la fois la génération des données (non disponibles) et la mise en place de processus capables de les exploiter dans un but d'identification. Des paramètres variables contrôlent la nature des images (richesse, niveau de bruit) tout au long de la simulation, ceci afin de pouvoir prendre en compte des données de qualité variable

Bottom-up strategies for the assembling of magnetic systems using nanoclusters

International audienceIn the frame of the 20th Anniversary of the Journal of Nanoparticle Research (JNR), our aim is to start from the historical context twenty, years ago and to give some recent results and perspectives concerning nanomagnets prepared from clusters preformed in the gas phase using the Low Energy Cluster Beam Deposition (LECBD) technique. In this paper, we focus our attention on the typical case of Co clusters embedded in various matrices to study interface magnetic anisotropy and magnetic interactions as a function of volume concentrations, and on still current and perspectives through two examples of binary metallic 3d-5d TM (namely CoPt and FeAu) clusters assemblies to illustrate size-related and nanoalloy phenomena on magnetic properties in well-defined mass-selected clusters. The structural and magnetic properties of these cluster assemblies were investigated using various experimental techniques that include High Resolution Transmission Electron Microscopy (HRTEM), Superconducting Quantum Interference Device (SQUID) magnetometry, as well as synchrotron techniques such as Extended X-Ray Absorption Fine Structure (EXAFS) and X-Ray Magnetic Circular Dichroism (XMCD). Depending on the chemical nature of both NPs and matrix, we observe different magnetic responses compared to their bulk counterparts. In particular, we show how finite size effects (size reduction) enhance their magnetic moment and how specific relaxation in nanoalloys can impact their magnetic anisotropy

EEAS 2.0: draft recommendations for the 2013 EEAS Review

This document offers recommendations for the amendment of Council Decision 2010/427/EU establishing the organisation and functioning of the European External Action Service (hereinafter ‘EEAS Decision’). These recommendations have been distilled from discussions between academics and practitioners during a two-day workshop held at the European University Institute in March 2013 in the framework of the so-called ‘EEAS 2.0’ project. This research project is a collaboration between independent scholars brought together by SIEPS, the EUI and CEPS. In February 2013, the team published a legal commentary on the EEAS Decision, available on the websites of the participating research centres. The current paper and its recommendations should be read in the light thereof. In formulating the recommendations, attention has been paid to policy papers, non-papers and recommendations that have been initiated by EU institutions, member states, think tanks and academia, notably in the context of the on-going review. As such, we hope to be able to inform, in a precise and legal way, the discussions in preparation of the High Representative’s own report. The current paper is work in progress and will be revisited for publication after the summer, taking into account the High Representative’s report of July and feedback from other stakeholders The current paper sheds light on possible adjustments in the operation of the Decision/Service ‘à droit constant’, but also includes proposals that could be considered in the context of an amendment of the EEAS Decision. With regard to the latter, several levels of revision may be envisaged: (i) a mere toilettage (e.g. deleting out-dated provisions and securing terminological consistency), (ii) technical changes in the text without reopening the political discussion that predated the adoption of the Decision and (iii) a more ambitious revision that could require more extensive legal modifications of collateral secondary measures (e.g. Staff and/or Financial regulations), if not of the founding treaties

Somatic stem cell differentiation is regulated by PI3K/Tor signaling in response to local cues

Stem cells reside in niches that provide signals to maintain self-renewal, and differentiation is viewed as a passive process that depends on loss of access to these signals. Here, we demonstrate that the differentiation of somatic cyst stem cells (CySCs) in the Drosophila testis is actively promoted by PI3K/Tor signaling, as CySCs lacking PI3K/Tor activity cannot differentiate properly. We find that an insulin peptide produced by somatic cells immediately outside of the stem cell niche acts locally to promote somatic differentiation through Insulin-like receptor (InR) activation. These results indicate that there is a local ‘differentiation' niche that upregulates PI3K/Tor signaling in the early daughters of CySCs. Finally, we demonstrate that CySCs secrete the Dilp-binding protein ImpL2, the Drosophila homolog of IGFBP7, into the stem cell niche, which blocks InR activation in CySCs. Thus, we show that somatic cell differentiation is controlled by PI3K/Tor signaling downstream of InR and that the local production of positive and negative InR signals regulates the differentiation niche. These results support a model in which leaving the stem cell niche and initiating differentiation are actively induced by signaling

Superluminal X-shaped beams propagating without distortion along a coaxial guide

In a previous paper [Phys. Rev. E64 (2001) 066603; e-print physics/0001039], we showed that localized Superluminal solutions to the Maxwell equations exist, which propagate down (non-evanescence) regions of a metallic cylindrical waveguide. In this paper we construct analogous non-dispersive waves propagating along coaxial cables. Such new solutions, in general, consist in trains of (undistorted) Superluminal "X-shaped" pulses. Particular attention is paid to the construction of finite total energy solutions. Any results of this kind may find application in the other fields in which an essential role is played by a wave-equation (like acoustics, geophysics, etc.). [PACS nos.: 03.50.De; 41.20;Jb; 83.50.Vr; 62.30.+d; 43.60.+d; 91.30.Fn; 04.30.Nk; 42.25.Bs; 46.40.Cd; 52.35.Lv. Keywords: Wave equations; Wave propagation; Localized beams; Superluminal waves; Coaxial cables; Bidirectional decomposition; Bessel beams; X-shaped waves; Maxwell equations; Microwaves; Optics; Special relativity; Coaxial metallic waveguides; Acoustics; Seismology; Mechanical waves; Elastic waves; Guided gravitational waves.]Comment: plain LaTeX file (22 pages), plus 15 figures; in press in Phys. Rev.