1,301 research outputs found

    Handwritten and Printed Text Separation in Real Document

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    The aim of the paper is to separate handwritten and printed text from a real document embedded with noise, graphics including annotations. Relying on run-length smoothing algorithm (RLSA), the extracted pseudo-lines and pseudo-words are used as basic blocks for classification. To handle this, a multi-class support vector machine (SVM) with Gaussian kernel performs a first labelling of each pseudo-word including the study of local neighbourhood. It then propagates the context between neighbours so that we can correct possible labelling errors. Considering running time complexity issue, we propose linear complexity methods where we use k-NN with constraint. When using a kd-tree, it is almost linearly proportional to the number of pseudo-words. The performance of our system is close to 90%, even when very small learning dataset where samples are basically composed of complex administrative documents.Comment: Machine Vision Applications (2013

    Spitzer Observations of Transient, Extended Dust in Two Elliptical Galaxies: New Evidence of Recent Feedback Energy Release in Galactic Cores

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    Spitzer observations of extended dust in two optically normal elliptical galaxies provide a new confirmation of buoyant feedback outflow in the hot gas atmospheres around these galaxies. AGN feedback energy is required to prevent wholesale cooling and star formation in these group-centered galaxies. In NGC 5044 we observe interstellar (presumably PAH) emission at 8 microns out to about 5 kpc. Both NGC 5044 and 4636 have extended 70 microns emission from cold dust exceeding that expected from stellar mass loss. The sputtering lifetime of this extended dust in the ~1keV interstellar gas, ~10^7 yrs, establishes the time when the dust first entered the hot gas. Evidently the extended dust originated in dusty disks or clouds, commonly observed in elliptical galaxy cores, that were disrupted, heated and buoyantly transported outward. The surviving central dust in NGC 5044 and 4636 has been disrupted into many small filaments. It is remarkable that the asymmetrically extended 8 micron emission in NGC 5044 is spatially coincident with Halpha+[NII] emission from warm gas. A calculation shows that dust-assisted cooling in buoyant hot gas moving out from the galactic core can cool within a few kpc in about ~10^7 yrs, explaining the optical line emission observed. The X-ray images of both galaxies are disturbed. All timescales for transient activity - restoration of equilibrium and buoyant transport in the hot gas, dynamics of surviving dust fragments, and dust sputtering - are consistent with a central release of feedback energy in both galaxies about 10^7 yrs ago.Comment: 13 pages. Accepted by ApJ; minor typos correcte

    The influence of twin boundaries on the Flux Line Lattice structure in YBaCuO: a study by Small Angle Neutron Scattering

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    The influence of Twin Boundaries (TB) on the Flux Line Lattice(FLL) structure was investigated by Small Angle Neutron Scattering (SANS). YBaCuO single crystals possessing different TB densities were studied. The SANS experiments show that the TB strongly modify the structure of the FLL. The flux lines meander as soon as the magnetic field makes an angle with the TB direction. According to the value of this angle but also to the ratio of the flux lines density over the TB density, one observes that the FLL exhibits two different unit cells in the plane perpendicular to the magnetic field. One is the classical hexagonal and anisotropic cell while the other is affected by an additional deformation induced by the TB. We discuss a possible relation between this deformation and the increase of the critical current usually observed in heavily twinned samples.Comment: accepted for publication in Phys Rev

    Îș\kappa-Poincar\'e invariant quantum field theories with KMS weight

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    A natural star product for 4-d Îș\kappa-Minkowski space is used to investigate various classes of Îș\kappa-Poincar\'e invariant scalar field theories with quartic interactions whose commutative limit coincides with the usual ϕ4\phi^4 theory. Îș\kappa-Poincar\'e invariance forces the integral involved in the actions to be a twisted trace, thus defining a KMS weight for the noncommutative (C*-)algebra modeling the Îș\kappa-Minkowski space. The associated modular group and Tomita modular operator are characterized. In all the field theories, the twist generates different planar one-loop contributions to the 2-point function which are at most UV linearly diverging. Some of these theories are free of UV/IR mixing. In the others, UV/IR mixing shows up in non-planar contributions to the 2-point function as a polynomial singularity at exceptional zero external momenta while staying finite at non-zero external momenta. These results are discussed together with the possibility for the KMS weight relative to the quantum space algebra to trigger the appearance of KMS state on the algebra of observables.Comment: 32 pages, several paragraphs added, published in PR

    Détermination des substrats lacustres par hydroacoustique : application au suivit de qualité morphologique

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    La diversitĂ© des Ă©cosystĂšmes lacustres s’explique en partie par la variĂ©tĂ© hydromorphologique des lacs ; la nature et la rĂ©partition du substrat qui tapisse leur fond sont des composantes de ce paramĂštre. C’est pour cela que la Directive Cadre sur l’Eau impose une description de la nature des sĂ©diments des plans d’eau. Plus gĂ©nĂ©ralement, la rĂ©partition des substrats peut ĂȘtre considĂ©rĂ©e comme un facteur de structuration des espĂšces biologiques qu’abrite un lac. Des outils traditionnels comme l’utilisation d’une benne Ă  sĂ©diment ou d’une camĂ©ra subaquatique permettent de dĂ©terminer la nature des substrats de maniĂšre trĂšs ponctuelle mais ces techniques atteignent leurs limites lorsque tout un plan d’eau doit ĂȘtre caractĂ©risĂ©. Depuis les annĂ©es 1980 des mĂ©thodes de caractĂ©risation des sĂ©diments utilisant des outils acoustiques qui permettent d’obtenir des informations en continu le long de parcours rĂ©alisĂ©s par un navire ont Ă©tĂ© dĂ©veloppĂ©es et commercialisĂ©es. Pour l’application aux Ă©cosystĂšmes lacustres, de part leur mise en oeuvre, les systĂšmes utilisant les Ă©chosondeurs mono‐faisceau paraissent les plus appropriĂ©s. Ces appareils permettent de rĂ©aliser des cartes de la rĂ©partition des substrats Ă  l’échelle du lac. Les informations pertinentes qui permettent de dĂ©crire un Ă©tat biologique potentiel ou de dĂ©finir un Ă©tat initial peuvent ĂȘtre ainsi intĂ©grer dans la mise en place des rĂ©seaux de suivi de la qualitĂ© des milieux. / The lake ecosystem diversity is explained, in part, by the hydromorphological diversity of lakes; nature and repartition of the substrata give information about this parameter. That is the reason why the European Water Framework imposes a substrata nature description of lakes. The substrata repartition could be considered as a factor of the biological structuring presents in lakes. Traditional tools like grab samplers or video cameras enable to determine the substrata nature but they are not appropriate for getting a high resolution description for an entire lake. From the beginning of the 80’s, acoustic devices specialized in seabed classification have been developed and commercialized. For lakebed surveys, systems using single beam sounders seem to be more appropriate; they enable to obtain maps of the lakebed at the whole lake scale. Information which describes a potential biological state can be used for the establishment of a quality monitoring

    Les statistiques financiĂšres permettent-elles d’apprĂ©hender les Ă©volutions liĂ©es Ă  la mondialisation ?

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    Les difficultĂ©s d’apprĂ©hension des diverses Ă©volutions liĂ©es Ă  la globalisation financiĂšre invitent Ă  un examen critique des dispositifs statistiques existants.Mondialisation, statistiques financiĂšres, sociĂ©tĂ©s multinationales, Ă©crans statistiques, hedge funds, marchĂ©s de grĂ© Ă  grĂ©, contreparties, rĂ©glementation, centres offshore, obligations dĂ©claratives (reporting requirements), balance des paiements, comptes nationaux financiers.

    The Stellar Population Histories of Early-Type Galaxies. II. Controlling Parameters of the Stellar Populations

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    We analyze single-stellar-population (SSP) equivalent parameters for 50 local elliptical galaxies as a function of their structural parameters. These galaxies fill a two-dimensional plane in the four-dimensional space of [Z/H], log t, log σ\sigma, and [E/Fe]. SSP age and velocity dispersion can be taken as the two independent parameters that specify a galaxy's location in this ``hyperplane.'' The hyperplane can be decomposed into two sub-relations: (1) a ``Z-plane,'' in which [Z/H] is a linear function of log σ\sigma and log t; and (2) a relation between [E/Fe] and σ\sigma in which [E/Fe] is larger in high-σ\sigma galaxies. Cluster and field ellipticals follow the same hyperplane, but their (σ\sigma,t) distributions within it differ. Nearly all cluster galaxies are old; the field ellipticals span a large range in SSP age. The tight Mg--σ\sigma relations of these ellipticals can be understood as two-dimensional projections of the metallicity hyperplane showing it edge-on; the tightness of these relations does not necessarily imply a narrow range of ages at fixed σ\sigma. The relation between [E/Fe] and σ\sigma is consistent with a higher effective yield of Type II SNe elements at higher σ\sigma. The Z-plane is harder to explain and may be a powerful clue to star formation in elliptical galaxies if it proves to be general. Present data favor a ``frosting'' model in which low apparent SSP ages are produced by adding a small frosting of younger stars to an older base population. If the frosting abundances are close to or slightly greater than the base population, simple two-component models run along lines of constant σ\sigma in the Z-plane, as required. This favors star formation from well-mixed pre-enriched gas rather than unmixed low-metallicity gas from an accreted object. (Abridged)Comment: To be published in the June 2000 issue of the Astronomical Journal. 28 pages, 13 figures, uses emulateap

    The Surface Brightness Fluctuations and Globular Cluster Populations of M87 and its Companions

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    Using the surface brightness fluctuations in HST WFPC-2 images, we determine that M87, NGC 4486B, and NGC 4478 are all at a distance of ~16 Mpc, while NGC 4476 lies in the background at ~21 Mpc. We also examine the globular clusters of M87 using archived HST fields. We detect the bimodal color distribution, and find that the amplitude of the red peak relative to the blue peak is greatest near the center. This feature is in good agreement with the merger model of elliptical galaxy formation, where some of the clusters originated in progenitor galaxies while other formed during mergers.Comment: 5 pages, 2 figure
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