47,609 research outputs found

    Using Qualitative Hypotheses to Identify Inaccurate Data

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    Identifying inaccurate data has long been regarded as a significant and difficult problem in AI. In this paper, we present a new method for identifying inaccurate data on the basis of qualitative correlations among related data. First, we introduce the definitions of related data and qualitative correlations among related data. Then we put forward a new concept called support coefficient function (SCF). SCF can be used to extract, represent, and calculate qualitative correlations among related data within a dataset. We propose an approach to determining dynamic shift intervals of inaccurate data, and an approach to calculating possibility of identifying inaccurate data, respectively. Both of the approaches are based on SCF. Finally we present an algorithm for identifying inaccurate data by using qualitative correlations among related data as confirmatory or disconfirmatory evidence. We have developed a practical system for interpreting infrared spectra by applying the method, and have fully tested the system against several hundred real spectra. The experimental results show that the method is significantly better than the conventional methods used in many similar systems.Comment: See http://www.jair.org/ for any accompanying file

    Hawking Radiation of an Arbitrarily Accelerating Kinnersley Black Hole: Spin-Acceleration Coupling Effect

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    The Hawking radiation of Weyl neutrinos in an arbitrarily accelerating Kinnersley black hole is investigated by using a method of the generalized tortoise coordinate transformation. Both the location and temperature of the event horizon depend on the time and on the angles. They coincide with previous results, but the thermal radiation spectrum of massless spinor particles displays a kind of spin-acceleration coupling effect.Comment: 8 pages, no figure, revtex 4.0, revisted version with typesetting errors and misprint correcte

    Bagging evolutionary feature extraction algorithm for classification

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    Author name used in this publication: David ZhangBiometrics Research Centre, Department of ComputingVersion of RecordPublishe

    Tracers of chromospheric structure. I. CaII H&\&K emission distribution of 13000 F, G and K stars in SDSS DR7 spectroscopic sample

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    We present chromospheric activity index SHKS\rm_{HK} measurements for over 13,000 F, G and K disk stars with high signal-to-noise ratio (>> 60) spectra in the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) spectroscopic sample. A parameter ÎŽ\deltaS is defined as the difference between SHKS\rm_{HK} and a `zero' emission line fitted by several of the most inactive stars. The SHKS\rm_{HK} indices of subgiant stars tend to be much lower than dwarfs, which provide a way to distinguish dwarfs and giants with relatively low resolution spectra. Cooler stars are generally more active and display a larger scatter than hotter stars. Stars associated with the thick disk are in general less active than those of the thin disk. The fraction of K dwarfs that are active drops with vertical distance from the Galactic plane. Metallicity affects SHKS\rm_{HK} measurements differently among F, G and K dwarfs in this sample. Using the open clusters NGC 2420, M67 and NGC6791 as calibrations, ages of most field stars in this SDSS sample range from 3-8 Gyr.Comment: 9 pages, 11 figures, AJ, 2013, 145, 14

    Non-existence of New Quantum Ergosphere Effect of a Vaidya-type Black Hole

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    Hawking evaporation of Dirac particles and scalar fields in a Vaidya-type black hole is investigated by the method of generalized tortoise coordinate transformation. It is shown that Hawking radiation of Dirac particles does not exist for P1,Q2P_1, Q_2 components but for P2,Q1P_2, Q_1 components in any Vaidya-type black holes. Both the location and the temperature of the event horizon change with time. The thermal radiation spectrum of Dirac particles is the same as that of Klein-Gordon particles. We demonstrates that there is no new quantum ergosphere effect in the thermal radiation of Dirac particles in any spherically symmetry black holes.Comment: Latex, 9 pages, no figure, submitted to Mod. Phys. Lett.

    Two Kinds of Iterative Solutions for Generalized Sombrero-shaped Potential in NN-dimensional Space

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    Based on two different iteration procedures the groundstate wave functions and energies for N-dimensional generalized Sombrero-shaped potentials are solved. Two kinds of trial functions for the iteration procedure are defined. The iterative solutions are convergent nicely to consistent results for different choices of iteration procedures and trial functions.Comment: 16 pages, 3 figure

    Relations Between Low-lying Quantum Wave Functions and Solutions of the Hamilton-Jacobi Equation

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    We discuss a new relation between the low lying Schroedinger wave function of a particle in a one-dimentional potential V and the solution of the corresponding Hamilton-Jacobi equation with -V as its potential. The function V is ≄0\geq 0, and can have several minina (V=0). We assume the problem to be characterized by a small anhamornicity parameter g−1g^{-1} and a much smaller quantum tunneling parameter Ï”\epsilon between these different minima. Expanding either the wave function or its energy as a formal double power series in g−1g^{-1} and Ï”\epsilon, we show how the coefficients of g−mÏ”ng^{-m}\epsilon^n in such an expansion can be expressed in terms of definite integrals, with leading order term determined by the classical solution of the Hamilton-Jacobi equation. A detailed analysis is given for the particular example of quartic potential V=1/2g2(x2−a2)2V={1/2}g^2(x^2-a^2)^2.Comment: LaTex, 48 pages, no figur

    Chemical composition of 90 F and G disk dwarfs

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    High resolution, high S/N spectra have been obtained for a sample of 90 F and G main-sequence disk stars covering the metallicity range -1.0 < [Fe/H] < +0.1, and have been analysed in a parallel way to the work of Edvardsson et al. (1993). Effective temperatures are based on the Alonso et al. (1996) calibration of color indices and surface gravities are calculated from Hipparcos parallaxes, which also allow more accurate ages to be calculated. In addition, more reliable kinematical parameters are derived from Hipparcos distances and proper motions. Finally, a larger spectral coverage, 5600 - 8800 A, makes it possible to improve the abundance accuracy by studying more lines and to discuss several elements not included in the work of Edvardsson et al. The present paper provides the data and discusses some general results of the abundance survey. A group of stars in the metallicity range of -1.0 < [Fe/H] < -0.6 having a small mean Galactocentric distance in the stellar orbits, Rm < 7 kpc, are shown to be older than the other disk stars and probably belong to the thick disk. Excluding these stars, a slight decreasing trend of [Fe/H] with increasing Rm and age is found, but a large scatter in [Fe/H] (up to 0.5 dex) is present at a given age and Rm. The derived trends of O, Mg, Si, Ca, Ti, Ni and Ba as a function of [Fe/H] agree rather well with those of Edvardsson et al., but the overabundance of Na and Al for metal-poor stars found in their work is not confirmed. Furthermore, the Galactic evolution of elements not included in Edvardsson et al., K, V and Cr, is studied.Comment: 16 pages with 10 figures. Accepted for publication in A&A
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