720 research outputs found

    Adaptive appearance learning for visual object tracking

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    This paper addresses online learning of reference object distribution in the context of two hybrid tracking schemes that combine the mean shift with local point feature correspondences, and the mean shift under the Bayesian framework, respectively. The reference object distribution is built up by a kernel-weighted color histogram. The main contributions of the proposed schemes includes: (a) an adaptive learning strategy that seeks to update the reference object distribution when the changes are caused by the intrinsic object dynamic without partial occlusion/ intersection; (b) novel dynamic maintenance of object feature points by exploring both foreground and background sets; (c) integration of adaptive appearance and local point features in joint object appearance similarity and local point features correspondences-based tracker to improve [7]; (d) integration of adaptive appearance in joint appearance similarity and particle filter tracker under the Bayesian framework to improve [10]. Experimental results on a range of videos captured by a dynamic/stationary camera demonstrate the effectiveness of the proposed schemes in terms of robustness to partial occlusions, tracking drifts and tightness and accuracy of tracked bounding box. Comparisons are also made with the two hybrid trackers together with 3 existing trackers

    Visual Tracking and Dynamic Learning on the Grassmann Manifold with Inference from a Bayesian Framework and State Space Models

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    We propose a novel visual tracking scheme that exploits both the geometrical structure of Grassmann manifold and piecewise geodesics under a Bayesian framework. Two particle filters are alternatingly employed on the manifold. One is used for online updating the appearance subspace on the manifold using sliding-window observations, and the other is for tracking moving objects on the manifold based on the dynamic shape and appearance models. Main contributions of the paper include: (a) proposing an online manifold learning strategy by a particle filter, where a mixture of dynamic models is used for both the changes of manifold bases in the tangent plane and the piecewise geodesics on the manifold. (b) proposing a manifold object tracker by incorporating object shape in the tangent plane and the manifold prediction error of object appearance jointly in a particle filter framework. Experiments performed on videos containing significant object pose changes show very robust tracking results. The proposed scheme also shows better performance as comparing with three existing trackers in terms of tracking drift and the tightness and accuracy of tracked boxes

    Followership moderation between the relationship of transactional leadership style and employees reactions towards organizational change

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    The purpose of the present study is to analyze the relationship between transactional leadership style and factors of employees’ reactions towards organizational change in the telecommunication companies of Pakistan. Furthermore, to understand the importance of followership this study has also incorporated followership as a moderating variable. Quantitative methodology is applied to investigate the underline relationships. The Pearson correlation results have identified that transactional leadership is positively related to all three factors (frequency of change, trust in management, and employees’ participation) of employees’ reactions towards change. The moderation results further clarify that followership significantly moderates the relationship between transactional leadership style, frequency of change and employees participation. However, there is no moderation effect found between transactional leadership style and trust in management.Celem niniejszego badania jest analiza związku między stylem przywĂłdztwa transakcyjnego a czynnikami reakcji pracownikĂłw na zmiany organizacyjne w przedsiębiorstwach telekomunikacyjnych w Pakistanie. Ponadto, aby zrozumieć znaczenie podÄ…ĆŒania za przywĂłdcą, zostaƂo ono wƂączone jako zmienna moderująca. W celu zbadania istniejących zaleĆŒnoƛci, zastosowana zostaƂa metodologia iloƛciowa. Wyniki korelacji Pearsona wykazaƂy, ĆŒe przywĂłdztwo transakcyjne jest pozytywnie powiązane ze wszystkimi trzema czynnikami (częstoƛcią zmian, zaufaniem do zarządzania i udziaƂem pracownikĂłw) reakcji pracownikĂłw na zmiany. Uzyskane wyniki pozwoliƂy stwierdzić, ĆŒe wyniki moderacji dodatkowo wyjaƛniƂy, ĆŒe podÄ…ĆŒanie za przywĂłdcą znacząco moderowaƂo związek pomiędzy stylem przywĂłdztwa transakcyjnego, częstotliwoƛcią zmian a udziaƂem pracownikĂłw. Jednak nie znaleziono efektu powiązania pomiędzy stylem przywĂłdztwa transakcyjnego a zaufaniem do zarządzania

    Measurement of the W+W-gamma Cross Section and Direct Limits on Anomalous Quartic Gauge Boson Couplings at LEP

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    The process e+e- -> W+W-gamma is analysed using the data collected with the L3 detector at LEP at a centre-of-mass energy of 188.6GeV, corresponding to an integrated luminosity of 176.8pb^-1. Based on a sample of 42 selected W+W- candidates containing an isolated hard photon, the W+W-gamma cross section, defined within phase-space cuts, is measured to be: sigma_WWgamma = 290 +/- 80 +/- 16 fb, consistent with the Standard Model expectation. Including the process e+e- -> nu nu gamma gamma, limits are derived on anomalous contributions to the Standard Model quartic vertices W+W- gamma gamma and W+W-Z gamma at 95% CL: -0.043 GeV^-2 < a_0/Lambda^2 < 0.043 GeV^-2 0.08 GeV^-2 < a_c/Lambda^2 < 0.13 GeV^-2 0.41 GeV^-2 < a_n/Lambda^2 < 0.37 GeV^-2

    Production of Single W Bosons at \sqrt{s}=189 GeV and Measurement of WWgamma Gauge Couplings

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    Single W boson production in electron-positron collisions is studied with the L3 detector at LEP. The data sample collected at a centre-of-mass energy of \sqrt{s} = 188.7GeV corresponds to an integrated luminosity of 176.4pb^-1. Events with a single energetic lepton or two acoplanar hadronic jets are selected. Within phase-space cuts, the total cross-section is measured to be 0.53 +/- 0.12 +/- 0.03 pb, consistent with the Standard Model expectation. Including our single W boson results obtained at lower \sqrt{s}, the WWgamma gauge couplings kappa_gamma and lambda_gamma are determined to be kappa_gamma = 0.93 +/- 0.16 +/- 0.09 and lambda_gamma = -0.31 +0.68 -0.19 +/- 0.13

    Search for an invisibly decaying Higgs boson in e^+e^- collisions at \sqrt{s} = 183 - 189 GeV

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    A search for a Higgs boson decaying into invisible particles is performed using the data collected at LEP by the L3 experiment at centre-of-mass energies of 183 GeV and 189 GeV. The integrated luminosities are respectively 55.3 pb^-1 and 176.4 pb^-1. The observed candidates are consistent with the expectations from Standard Model processes. In the hypothesis that the production cross section of this Higgs boson equals the Standard Model one and the branching ratio into invisible particles is 100%, a lower mass limit of 89.2 GeV is set at 95% confidence level

    Search for Neutral Higgs Bosons of the Minimal Supersymmetric Standard Model in e+e- Interactions at \sqrt{s} = 189 GeV

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    A search for the lightest neutral scalar and neutral pseudoscalar Higgs bosons in the Minimal Supersymmetric Standard Model is performed using 176.4 pb^-1 of integrated luminosity collected by L3 at a center-of-mass energy of 189 GeV. No signal is observed, and the data are consistent with the expected Standard Model background. Lower limits on the masses of the lightest neutral scalar and pseudoscalar Higgs bosons are given as a function of tan(beta). Lower mass limits for tan(beta)>1 are set at the 95% confidence level to be m_h > 77.1 GeV and m_A > 77.1 GeV

    Measurement of Bose-Einstein Correlations in e+e- -> W+W- at root(s)=189GeV

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    We investigate Bose-Einstein correlations (BEC) in W-pair production at root(s)=189GeV using the L3 detector at LEP. We observe BEC between particles from a single W decay in good agreement with those from a light-quark Z decay sample. We investigate their possible existence between particles coming from different W's. No evidence for such inter-W BEC is found
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