1,591 research outputs found

    Quantifying appearance retention in carpets using geometrical local binary patterns

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    Quality assessment in carpet manufacturing is performed by humans who evaluate the appearance retention (AR) grade on carpet samples. To quantify the AR grades objectively, different research based on computer vision have been developed. Among them Local Binary Pattern (LBP) and its variations has shown promising results. Nevertheless, the requirements of quality assessment on a wide range of carpets have not been met yet. One of the difficulties is to distinguish between consecutive AR grades in carpets. For this, we adopt an extension of LBP called Geometrical Local Binary Patterns (GLBP) that we recently proposed. The basis of GLBP is to evaluate the grey scale differences between adjacent points defined on a path in a neighbourhood. Symmetries of the paths in the GLBPs are evaluated. The proposed technique is compared with an invariant rotational mirror based LBP technique. The results show that the GLBP technique performs better to distinguish consecutive AR grades in carpets

    Bayesian Analysis of Individual Level Personality Dynamics

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    A Bayesian technique with analyses of within-person processes at the level of the individual is presented. The approach is used to examine whether the patterns of within-person responses on a 12-trial simulation task are consistent with the predictions of ITA theory (Dweck, 1999). ITA theory states that the performance of an individual with an entity theory of ability is more likely to spiral down following a failure experience than the performance of an individual with an incremental theory of ability. This is because entity theorists interpret failure experiences as evidence of a lack of ability which they believe is largely innate and therefore relatively fixed; whilst incremental theorists believe in the malleability of abilities and interpret failure experiences as evidence of more controllable factors such as poor strategy or lack of effort. The results of our analyses support ITA theory at both the within- and between-person levels of analyses and demonstrate the benefits of Bayesian techniques for the analysis of within-person processes. These include more formal specification of the theory and the ability to draw inferences about each individual, which allows for more nuanced interpretations of individuals within a personality category, such as differences in the individual probabilities of spiraling. While Bayesian techniques have many potential advantages for the analyses of processes at the level of the individual, ease of use is not one of them for psychologists trained in traditional frequentist statistical techniques

    Influence of kNN-Based Load Forecasting Errors on Optimal Energy Production

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    This paper presents a study of the influence of the accuracy of hourly load forecasting on the energy planning and operation of electric generation utilities. First, a k Nearest Neighbours (kNN) classification technique is proposed for hourly load forecasting. Then, obtained prediction errors are compared with those obtained results by using a M5’. Second, the obtained kNN-based load forecast is used to compute the optimal on/off status and generation scheduling of the units. Finally, the influence of forecasting errors on both the status and generation level of the units over the scheduling period is studied

    Probing the Deuteron at Very Large Internal Momenta

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    We measure 2H(e,e′p)n cross sections at 4-momentum transfers of Q2 = 4.5 ± 0.5   (GeV/c)2 over a range of neutron recoil momenta pr, reaching up to ∼1.0  GeV/c. We obtain data at fixed neutron recoil angles θnq = 35°, 45°, and 75° with respect to the 3-momentum transfer →q. The new data agree well with previous data, which reached pr ∼ 500  MeV/c. At θnq = 35° and 45°, final state interactions, meson exchange currents, and isobar currents are suppressed and the plane wave impulse approximation provides the dominant cross section contribution. We compare the new data to recent theoretical calculations, where we observe a significant discrepancy for recoil momenta pr \u3e 700  MeV/c

    Measurement of the 6s - 7p transition probabilities in atomic cesium and a revised value for the weak charge Q_W

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    We have measured the 6s - 7p_{1/2,3/2} transition probabilities in atomic cesium using a direct absorption technique. We use our result plus other previously measured transition rates to derive an accurate value of the vector transition polarizability \beta and, consequently, re-evaluate the weak charge Q_W. Our derived value Q_W=-72.65(49) agrees with the prediction of the standard model to within one standard deviation.Comment: 4 pages, 2 figure

    Parity nonconservation in heavy atoms: The radiative correction enhanced by the strong electric field of the nucleus

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    Parity nonconservation due to the nuclear weak charge is considered. We demonstrate that the radiative corrections to this effect due to the vacuum fluctuations of the characteristic size larger than the nuclear radius r0r_0 and smaller than the electron Compton wave-length λC\lambda_C are enhanced because of the strong electric field of the nucleus. The parameter that allows one to classify the corrections is the large logarithm ln(λC/r0)\ln(\lambda_C/r_0). The vacuum polarization contribution is enhanced by the second power of the logarithm. Although the self-energy and the vertex corrections do not vanish, they contain only the first power of the logarithm. The value of the radiative correction is 0.4% for Cs and 0.9% for Tl, Pb, and Bi. We discuss also how the correction affects the interpretation of the experimental data on parity nonconservation in atoms.Comment: 4 pages, 3 figures, RevTe

    Accuracy and Limitations of Fitting and Stereoscopic Methods to Determine the Direction of Coronal Mass Ejections from Heliospheric Imagers Observations

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    Using data from the Heliospheric Imagers (HIs) onboard STEREO, it is possible to derive the direction of propagation of coronal mass ejections (CMEs) in addition to their speed with a variety of methods. For CMEs observed by both STEREO spacecraft, it is possible to derive their direction using simultaneous observations from the twin spacecraft and also, using observations from only one spacecraft with fitting methods. This makes it possible to test and compare different analyses techniques. In this article, we propose a new fitting method based on observations from one spacecraft, which we compare to the commonly used fitting method of Sheeley et al. (1999). We also compare the results from these two fitting methods with those from two stereoscopic methods, focusing on 12 CMEs observed simultaneously by the two STEREO spacecraft in 2008 and 2009. We find evidence that the fitting method of Sheeley et al. (1999) can result in significant errors in the determination of the CME direction when the CME propagates outside of 60deg \pm 20 deg from the Sun-spacecraft line. We expect our new fitting method to be better adapted to the analysis of halo or limb CMEs with respect to the observing spacecraft. We also find some evidence that direct triangulation in the HI fields-of-view should only be applied to CMEs propagating approximatively towards Earth (\pm 20deg from the Sun-Earth line). Last, we address one of the possible sources of errors of fitting methods: the assumption of radial propagation. Using stereoscopic methods, we find that at least seven of the 12 studied CMEs had an heliospheric deflection of less than 20deg as they propagated in the HI fields-of-view, which, we believe, validates this approximation.Comment: 17 pages, 6 figures, 2 tables, accepted to Solar Physic

    Uncertainty and Urban Life

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    This essay examines the influence of uncertainty on how contemporary cities are planned, built, governed, and inhabited. This influence is demonstrated through the analysis of various domains of urban planning and governance (disaster, security, energy, and transportation) across four cities of the global South (Bogotá, Karachi, Accra, and Johannesburg). In each city, uncertainty is produced by historical conditions and productive of future possibilities

    A comparison of DA white dwarf temperatures and gravities from Lyman and Balmer line studies

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    We present measurements of the effective temperatures and surface gravities for a sample of hot DA white dwarfs, using the Lyman line data available from the HUT, ORFEUS and FUSE far-UV space missions. Comparing the results with those from the standard Balmer line technique, we find that there is a general good overall agreement between the two methods. However, significant differences are found for a number of stars, but not always of a consistent nature in that sometimes the Balmer temperature exceeds that derived from the Lyman lines and in other instances is lower. We conclude that, with the latest model atmosphere calculations, these discrepancies probably do not arise from an inadequate theoretical treatment of the Lyman lines but rather from systematic effects in the observation and data reduction processes, which dominate the statistical errors in these spectra. If these systematic data reduction effects can be adequately controlled, the Lyman line temperature and gravity measurements are consistent with those obtained from the Balmer lines when allowance is made for reasonable observational uncertainties.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Society 14 pages, 13 figure

    High-precision determination of transition amplitudes of principal transitions in Cs from van der Waals coefficient C_6

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    A method for determination of atomic dipole matrix elements of principal transitions from the value of dispersion coefficient C_6 of molecular potentials correlating to two ground-state atoms is proposed. The method is illustrated on atomic Cs using C_6 deduced from high-resolution Feshbach spectroscopy. The following reduced matrix elements are determined < 6S_{1/2} || D || 6P_{1/2} > =4.5028(60) |e| a0 and =6.3373(84) |e| a0 (a0= 0.529177 \times 10^{-8} cm.) These matrix elements are consistent with the results of the most accurate direct lifetime measurements and have a similar uncertainty. It is argued that the uncertainty can be considerably reduced as the coefficient C_6 is constrained further.Comment: 4 pages; 3 fig
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