541 research outputs found

    Modeling Web Services by Iterative Reformulation of Functional and Non-Functional Requirements

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    Abstract. We propose an approach for incremental modeling of composite Web services. The technique takes into consideration both the functional and nonfunctional requirements of the composition. While the functional requirements are described using symbolic transition systems—transition systems augmented with state variables, function invocations, and guards; non-functional requirements are quantified using thresholds. The approach allows users to specify an abstract and possibly incomplete specification of the desired service (goal) that can be realized by selecting and composing a set of pre-existing services. In the event that such a composition is unrealizable, i.e. the composition is not functionally equivalent to the goal or the non-functional requirements are violated, our system provides the user with the causes for the failure, that can be used to appropriately reformulate the functional and/or non-functional requirements of the goal specification.

    Brane decay of a (4+n)-dimensional rotating black hole: spin-0 particles

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    In this work, we study the `scalar channel' of the emission of Hawking radiation from a (4+n)-dimensional, rotating black hole on the brane. We numerically solve both the radial and angular part of the equation of motion for the scalar field, and determine the exact values of the absorption probability and of the spheroidal harmonics, respectively. With these, we calculate the particle, energy and angular momentum emission rates, as well as the angular variation in the flux and power spectra -- a distinctive feature of emission during the spin-down phase of the life of the produced black hole. Our analysis is free from any approximations, with our results being valid for arbitrarily large values of the energy of the emitted particle, angular momentum of the black hole and dimensionality of spacetime. We finally compute the total emissivities for the number of particles, energy and angular momentum and compare their relative behaviour for different values of the parameters of the theory.Comment: 24 pages, 13 figure

    Brane Decay of a (4+n)-Dimensional Rotating Black Hole. III: spin-1/2 particles

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    In this work, we have continued the study of the Hawking radiation on the brane from a higher-dimensional rotating black hole by investigating the emission of fermionic modes. A comprehensive analysis is performed that leads to the particle, power and angular momentum emission rates, and sheds light on their dependence on fundamental parameters of the theory, such as the spacetime dimension and angular momentum of the black hole. In addition, the angular distribution of the emitted modes, in terms of the number of particles and energy, is thoroughly studied. Our results are valid for arbitrary values of the energy of the emitted particles, dimension of spacetime and angular momentum of the black hole, and complement previous results on the emission of brane-localised scalars and gauge bosons.Comment: Latex file, JHEP style, 34 pages, 16 figures Energy range in plots increased, minor changes, version published in JHE

    Viabilidade de uso do híbrido Hawaii 7996 como porta-enxerto de cultuvares comerciais de tomate.

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    A técnica de enxertia é utilizada em algumas hortaliças, principalmente em áreas infestadas, para atribuir resistência a patógenos do solo, minimizando as perdas de produção de cultivares suscetíveis. Este trabalho teve como objetivo avaliar o desenvolvimento e a produtividade de plantas de tomateiro enxertadas em híbrido, tido como resistente a Ralstonia solanacearum, em comparação a pés-francos. O experimento foi desenvolvido em viveiro (produção de mudas e enxertia) e em céu aberto, no município de Cruz das Almas, Bahia, no período de outubro de 2003 a fevereiro de 2004. Utilizou-se o método de enxertia de fenda cheia, com o híbrido ‘Hawaii 7996’ como porta-enxerto e as cultivares Santa Clara, Santa Cruz Kada e Débora Plus, suscetíveis a R. solanacearum, como enxerto. O delineamento experimental foi em blocos ao acaso, com seis tratamentos (3 enxertados e 3 pés-francos), 5 repetições e 6 plantas por parcela útil. Avaliaram-se os caracteres: diâmetro do caule, altura da planta e da primeira inflorescência, distância entre inflorescências e produtividade comercial de frutos. O desenvolvimento das plantas, a produção total e a massa média dos frutos foram semelhantes para os tratamentos enxertados em relação a seus respectivos pés-francos e não houve incompatibilidade entre porta-enxerto e enxerto. A cultivar Santa Cruz Kada foi mais sensível às condições agroecológicas do município de Cruz das Almas, refletindo negativamente na produção e no peso médio dos frutos. Observou-se na enxertia com o híbrido ‘Hawaii 7996’ potencial para viabilizar a produção de tomateiros comerciais suscetíveis à murcha bacteriana, em áreas infestadas com R. solanacearum

    BB flavour tagging using charm decays at the LHCb experiment

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    An algorithm is described for tagging the flavour content at production of neutral BB mesons in the LHCb experiment. The algorithm exploits the correlation of the flavour of a BB meson with the charge of a reconstructed secondary charm hadron from the decay of the other bb hadron produced in the proton-proton collision. Charm hadron candidates are identified in a number of fully or partially reconstructed Cabibbo-favoured decay modes. The algorithm is calibrated on the self-tagged decay modes B+J/ψK+B^+ \to J/\psi \, K^+ and B0J/ψK0B^0 \to J/\psi \, K^{*0} using 3.0fb13.0\mathrm{\,fb}^{-1} of data collected by the LHCb experiment at pppp centre-of-mass energies of 7TeV7\mathrm{\,TeV} and 8TeV8\mathrm{\,TeV}. Its tagging power on these samples of BJ/ψXB \to J/\psi \, X decays is (0.30±0.01±0.01)%(0.30 \pm 0.01 \pm 0.01) \%.Comment: All figures and tables, along with any supplementary material and additional information, are available at http://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-027.htm

    Evidence for the strangeness-changing weak decay ΞbΛb0π\Xi_b^-\to\Lambda_b^0\pi^-

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    Using a pppp collision data sample corresponding to an integrated luminosity of 3.0~fb1^{-1}, collected by the LHCb detector, we present the first search for the strangeness-changing weak decay ΞbΛb0π\Xi_b^-\to\Lambda_b^0\pi^-. No bb hadron decay of this type has been seen before. A signal for this decay, corresponding to a significance of 3.2 standard deviations, is reported. The relative rate is measured to be fΞbfΛb0B(ΞbΛb0π)=(5.7±1.80.9+0.8)×104{{f_{\Xi_b^-}}\over{f_{\Lambda_b^0}}}{\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-) = (5.7\pm1.8^{+0.8}_{-0.9})\times10^{-4}, where fΞbf_{\Xi_b^-} and fΛb0f_{\Lambda_b^0} are the bΞbb\to\Xi_b^- and bΛb0b\to\Lambda_b^0 fragmentation fractions, and B(ΞbΛb0π){\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-) is the branching fraction. Assuming fΞb/fΛb0f_{\Xi_b^-}/f_{\Lambda_b^0} is bounded between 0.1 and 0.3, the branching fraction B(ΞbΛb0π){\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-) would lie in the range from (0.57±0.21)%(0.57\pm0.21)\% to (0.19±0.07)%(0.19\pm0.07)\%.Comment: 7 pages, 2 figures, All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-047.htm

    ICA vs. PCA Active Appearance Models: Application to Cardiac MR Segmentation

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    Abstract. Statistical shape models generally use Principal Component Analysis (PCA) to describe the main directions of shape variation in a training set of ex-ample shapes. However, PCA has the restriction that the input data must be drawn from a Gaussian distribution and is only able to describe global shape variations. In this paper we evaluate the use of an alternative shape decomposi-tion, Independent Component Analysis (ICA), for two reasons. ICA does not require a Gaussian distribution of the input data and is able to describe localized shape variations. With ICA however, the resulting vectors are not ordered, therefore a method for ordering the Independent Components is presented in this paper. To evaluate ICA-based Active Appearance Models (AAMs), 10 leave-15-out models were trained on a set of 150 short-axis cardiac MR Images with PCA-based as well as ICA-based AAMs. The median values for the aver-age and maximal point-to-point distances between the expert drawn and auto-matically segmented contours for the PCA-based AAM were 2.95 and 8.39 pix-els. For the ICA-based AAM these distances were 1.86 and 5.01 pixels respec-tively. From this, we conclude that the use of ICA results in a substantial im-provement in border localization accuracy over a PCA-based model.

    Absolute luminosity measurements with the LHCb detector at the LHC

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    Absolute luminosity measurements are of general interest for colliding-beam experiments at storage rings. These measurements are necessary to determine the absolute cross-sections of reaction processes and are valuable to quantify the performance of the accelerator. Using data taken in 2010, LHCb has applied two methods to determine the absolute scale of its luminosity measurements for proton-proton collisions at the LHC with a centre-of-mass energy of 7 TeV. In addition to the classic "van der Meer scan" method a novel technique has been developed which makes use of direct imaging of the individual beams using beam-gas and beam-beam interactions. This beam imaging method is made possible by the high resolution of the LHCb vertex detector and the close proximity of the detector to the beams, and allows beam parameters such as positions, angles and widths to be determined. The results of the two methods have comparable precision and are in good agreement. Combining the two methods, an overall precision of 3.5% in the absolute luminosity determination is reached. The techniques used to transport the absolute luminosity calibration to the full 2010 data-taking period are presented.Comment: 48 pages, 19 figures. Results unchanged, improved clarity of Table 6, 9 and 10 and corresponding explanation in the tex

    Absolute luminosity measurements with the LHCb detector at the LHC

    Get PDF
    Absolute luminosity measurements are of general interest for colliding-beam experiments at storage rings. These measurements are necessary to determine the absolute cross-sections of reaction processes and are valuable to quantify the performance of the accelerator. Using data taken in 2010, LHCb has applied two methods to determine the absolute scale of its luminosity measurements for proton-proton collisions at the LHC with a centre-of-mass energy of 7 TeV. In addition to the classic "van der Meer scan" method a novel technique has been developed which makes use of direct imaging of the individual beams using beam-gas and beam-beam interactions. This beam imaging method is made possible by the high resolution of the LHCb vertex detector and the close proximity of the detector to the beams, and allows beam parameters such as positions, angles and widths to be determined. The results of the two methods have comparable precision and are in good agreement. Combining the two methods, an overall precision of 3.5% in the absolute luminosity determination is reached. The techniques used to transport the absolute luminosity calibration to the full 2010 data-taking period are presented.Comment: 48 pages, 19 figures. Results unchanged, improved clarity of Table 6, 9 and 10 and corresponding explanation in the tex

    Absolute luminosity measurements with the LHCb detector at the LHC

    Get PDF
    Absolute luminosity measurements are of general interest for colliding-beam experiments at storage rings. These measurements are necessary to determine the absolute cross-sections of reaction processes and are valuable to quantify the performance of the accelerator. Using data taken in 2010, LHCb has applied two methods to determine the absolute scale of its luminosity measurements for proton-proton collisions at the LHC with a centre-of-mass energy of 7 TeV. In addition to the classic "van der Meer scan" method a novel technique has been developed which makes use of direct imaging of the individual beams using beam-gas and beam-beam interactions. This beam imaging method is made possible by the high resolution of the LHCb vertex detector and the close proximity of the detector to the beams, and allows beam parameters such as positions, angles and widths to be determined. The results of the two methods have comparable precision and are in good agreement. Combining the two methods, an overall precision of 3.5% in the absolute luminosity determination is reached. The techniques used to transport the absolute luminosity calibration to the full 2010 data-taking period are presented.Comment: 48 pages, 19 figures. Results unchanged, improved clarity of Table 6, 9 and 10 and corresponding explanation in the tex
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