227 research outputs found

    Applying method of phase plane to a fuzzy trend when predicting the project metrics presented by time series

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    In the article is proposed the method of applying the entropy measure to the fuzzy trend of time series of design metrics. An analysis of project performance is described. A prediction algorithm has been developed and implemented. The algorithm is based on the indices of fuzzy trends in time series. The formula for the entropy measure according to the fuzzy trend for a fuzzy time series is defined. The measure of entropy uses statistical information on the behavior of a fuzzy trend on the phase plane. The hypothesis of trend stability is used for forecasting. Experiments based on this approach are presented.The article was supported by the Russian Foundation for Basic Research (grant No. 19-07-00999)

    Application of the anomaly pattern in forecasting time series of project activity metrics

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    This article describes the method of application of an anomaly template of time series of project metrics based on entropy. The analysis of project activity metrics is described. The forecasting algorithm based on the fuzzy trends of time series of indicators was developed and implemented. The formula for the entropy measure for the fuzzy time series is determined. The algorithm uses the dependence of the forecast on the measures of entropy. The hypothesis of trend stability is used for forecasting. Experiments based on this approach are presented.The article was supported by the Russian Foundation for Basic Research (grant No. 16-47-732070)

    NMR in Superfluid A-like Phase of 3^3He Confined in Globally Deformed Aerogel in Tilted Magnetic Field

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    NMR spectra in superfluid A-like phases confined in axially deformed aerogel in presence of a magnetic field inclined with respect to deformation axis is considered. The characteristic features of dipole frequency shift in axially compressed and axially stretched cases are compared. In particular, it is shown that in axially stretched aerogel environment the stability region of coherently spin precessing mode is rather narrow due to the U(1)LIM effect.Comment: 8 pages, 2 figure

    Spin Transistor and Quantum Spin Hall Effects in CdBxF2-x - p-CdF2 - CdBxF2-x Sandwich Nanostructures

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    Planar CdBxF2-x - p-CdF2 - CdBxF2-x sandwich nanostructures prepared on the surface of the n-type CdF2 bulk crystal are studied to register the spin transistor and quantum spin Hall effects. The current-voltage characteristics of the ultra-shallow p+-n junctions verify the CdF2 gap, 7.8 eV, and the quantum subbands of the 2D holes in the p-type CdF2 quantum well confined by the CdBxF2-x delta-barriers. The temperature and magnetic field dependencies of the resistance, specific heat and magnetic susceptibility demonstrate the high temperature superconductor properties for the CdBxF2-x delta-barriers. The value of the superconductor energy gap, 102.06 meV, determined by the tunneling spectroscopy method appears to be in a good agreement with the relationship between the zero-resistance supercurrent in superconductor state and the conductance in normal state at the energies of the 2D hole subbands. The results obtained are evidence of the important role of the multiple Andreev reflections in the creation of the high spin polarization of the 2D holes in the edged channels of the sandwich device. The high spin hole polarization in the edged channels is shown to identify the mechanism of the spin transistor and quantum spin Hall effects induced by varying the top gate voltage, which is revealed by the first observation of the Hall quantum conductance staircase.Comment: 5 pages, 9 figure

    The magnetic ordering in the mixed valence compound beta-Na0.33V2O5

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    The low-temperature electron spin resonance (ESR) spectra and the static magnetization data obtained for the stoichiometric single crystals of β\beta-Na0.33_{0.33}V2_2O5_5 indicate that this quasi-one-dimensional mixed valence (V4+/V5+) compound demonstrates at TN=22T_N=22 K the phase transition into the canted antiferromagnetically ordered state. The spontaneous magnetization of 3.4×1033.4\times 10^{-3} μB\mu_B per V4+^{4+} ion was found to be oriented along the two-fold bb axis of the monoclinic structure, the vector of antiferromagnetism is aligned with the aa axis and the Dzyaloshinsky vector is parallel to the cc-axis. The experimental data were successfully described in the frame of the macroscopic spin dynamics and the following values for the macroscopic parameters of the spin system were obtained: the Dzyaloshinsky field HD=6H_D=6 kOe, the energy gaps of two branches of the spin wave spectrum Δ1=48\Delta_1=48 GHz and Δ2=24\Delta_2=24 GHz.Comment: 5 pages, 6 figure

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

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    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

    Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

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    The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

    Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

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    We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters
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