257,746 research outputs found

    Effect of single-value response styles on latent factor model convergence and measures of fit

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    This research examines the effects of single-value response style contamination on measures of model fit and model convergence issues. A simulation study examines the effects resulting from percentage of contamination, number of manifest, number of reverse coded items, magnitude of standardized factor loadings, response scale granularity, and sample size. Initial results indicate that sample size, scale granularity, factor loadings and number of manifest items had little to no effect on measures of fit. Both percent contamination and number of reverse coded items had a large effect on measures of fit. Measures of fit were more readily effected by percent contamination in models with higher standardized factor loadings. Model convergence issues were most strongly related to percent contamination and factor loadings

    Random contamination and select response styles affecting measures of fit and reliability in factor analysis

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    This research examines the effects of nonattending response pattern contamination and select response style patterns on measures of model fit (CFI) and internal reliability (Cronbach's α). A simulation study examines the effects resulting from percentage of contamination, number of manifest items measured and sample size. Initial results indicate that sample size very mildly affects CFI but does not influence α. Percent contamination decreases both CFI and α in a nearly linear fashion over a limited range of contamination. Finally, whereas an increase in the number of manifest items increases resilience to random contamination for α, the opposite was observed for CFI. An increase in the number of manifest items resulted in larger decreases in CFI. Implications are briefly discussed

    Second-order SM approach to SISO time-delay system output tracking

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    A fully linearizable single-input-single-output relative-degree n system with an output time delay is considered in this paper. Using the approach of Pade approximation, system center approach, and second-order sliding-mode (SM) control, we have obtained good output tracking results. The Smith predictor is used to compensate the difference between the actual delayed output and its approximation. A second-order supertwisting SM observer observes the disturbance in the plant. A nonlinear example is studied to show the effect of this methodology

    Phase Retrieval by Linear Algebra

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    The null vector method, based on a simple linear algebraic concept, is proposed as a solution to the phase retrieval problem. In the case with complex Gaussian random measurement matrices, a non-asymptotic error bound is derived, yielding an asymptotic regime of accurate approximation comparable to that for the spectral vector method

    On length spectrum metrics and weak metrics on TeichmĂŒller spaces of surfaces with boundary

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    We define and study metrics and weak metrics on the TeichmĂŒller space of a surface of topologically finite type with boundary. These metrics and weak metrics are associated to the hyperbolic length spectrum of simple closed curves and of properly embedded arcs in the surface. We give a comparison between the defined metrics on regions of TeichmĂŒller space which we call Δ0\varepsilon_0-relative Ï”\epsilon-thick parts} for Ï”>0\epsilon >0 and Δ0≄ϔ>0\varepsilon_0\geq \epsilon>0

    Virtual Compton Scattering from the Proton and the Properties of Nucleon Excited States

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    We calculate the N∗N^* contributions to the generalized polarizabilities of the proton in virtual Compton scattering. The following nucleon excitations are included: N∗(1535)N^*(1535), N∗(1650)N^*(1650), N∗(1520)N^*(1520), N∗(1700)N^*(1700), Δ(1232)\Delta(1232), Δ∗(1620)\Delta^*(1620) and Δ∗(1700)\Delta^*(1700). The relationship between nucleon structure parameters, N∗N^* properties and the generalized polarizabilities of the proton is illustrated.Comment: 13 pages of text (Latex) plus 4 figures (as uuencoded Z-compressed .tar file created by csh script uufiles

    Water resources planning for rivers draining into Mobile Bay. Part 2: Non-conservative species transport models

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    Total coliform group bacteria were selected to expand the mathematical modeling capabilities of the hydrodynamic and salinity models to understand their relationship to commercial fishing ventures within bay waters and to gain a clear insight into the effect that rivers draining into the bay have on water quality conditions. Parametric observations revealed that temperature factors and river flow rate have a pronounced effect on the concentration profiles, while wind conditions showed only slight effects. An examination of coliform group loading concentrations at constant river flow rates and temperature shows these loading changes have an appreciable influence on total coliform distribution within Mobile Bay
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