11,909 research outputs found

    THE COST OF INACCURATE AUTOMOBILE MILEAGE INFORMATION

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    The model in this paper integrates the possibility of misinformation into consumer utility theory. If the utility realized from a good differs from the utility anticipated at time of purchase, shifts in demand would occur, and thus changes in consumer surplus. These changes provide a measure of the cost of misinformation or value of improved information. The empirical analysis yields estimates of the private and social cost of inaccuracies in automobile buyers; pre-purchase mileage estimates. If automobile purchases are based on imperfect gasoline mileage information, a discrepancy results between expected and actual fuel-efficiency. The data source is a survey of 1980 model car buyers conducted by the authors.Consumer/Household Economics,

    THE COST OF INACCURATE CONSUMER INFORMATION: THE CASE OF THE EPA MILEAGE FIGURES

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    In this study a utility maximizing model is developed which accommodates changing states of information. Rational consumer choices in one state of information can lead to realizing different levels of utility than anticipated. Differences between these levels of utility suggest a measure for the value of information. This framework is applied to estimating the potential cost of possible inaccuracies in the EPA fuel-economy ratings. Survey data collected from new car buyers then are used to infer the magnitude of the actual costs that may be caused by the present EPA information.Consumer/Household Economics,

    Unification of some advection schemes in two dimensions

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    The relationship between two approaches towards construction of genuinely two-dimensional upwind advection schemes is established. One of these approaches is of the control volume type applicable on structured cartesian meshes. It resulted in the compact high resolution schemes capable of maintaining second order accuracy in both homogeneous and inhomogeneous cases. Another one is the fluctuation splitting approach, which is well suited for triangular (and possibly) unstructured meshes. Understanding the relationship between these two approaches allows us to formulate here a new fluctuation splitting high resolution (i.e. possible use of artificial compression, while maintaining positivity property) scheme. This scheme is shown to be linearity preserving in inhomogeneous as well as homogeneous cases

    Direct measurement of the size of 2003 UB313 from the Hubble Space Telescope

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    We have used the Hubble Space Telescope to directly measure the angular size of the large Kuiper belt object 2003 UB313. By carefully calibrating the point spread function of a nearby field star, we measure the size of 2003 UB313 to be 34.3±\pm1.4 milliarcseconds, corresponding to a diameter of 2400±\pm100 km or a size 5\sim5% larger than Pluto. The V band geometric albedo of 2003 UB313 is 86±786\pm7%. The extremely high albedo is consistent with the frosty methane spectrum, the lack of red coloring, and the lack of observed photometric variation on the surface of 2003 UB313. Methane photolysis should quickly darken the surface of 2003 UB313, but continuous evaporation and redeposition of surface ices appears capable of maintaining the extreme alebdo of this body

    Evaluation of Euler Fluxes for Hypersonic Flow Computations

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76462/1/AIAA-33735-324.pd

    Inference for bounded parameters

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    The estimation of signal frequency count in the presence of background noise has had much discussion in the recent physics literature, and Mandelkern [1] brings the central issues to the statistical community, leading in turn to extensive discussion by statisticians. The primary focus however in [1] and the accompanying discussion is on the construction of a confidence interval. We argue that the likelihood function and pp-value function provide a comprehensive presentation of the information available from the model and the data. This is illustrated for Gaussian and Poisson models with lower bounds for the mean parameter

    High Order Upwind Schemes for Multidimensional Magnetohydrodynamics

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    A general method for constructing high order upwind schemes for multidimensional magnetohydrodynamics (MHD), having as a main built-in condition the divergence-free constraint \divb=0 for the magnetic field vector \bb, is proposed. The suggested procedure is based on {\em consistency} arguments, by taking into account the specific operator structure of MHD equations with respect to the reference Euler equations of gas-dynamics. This approach leads in a natural way to a staggered representation of the \bb field numerical data where the divergence-free condition in the cell-averaged form, corresponding to second order accurate numerical derivatives, is exactly fulfilled. To extend this property to higher order schemes, we then give general prescriptions to satisfy a (r+1)th(r+1)^{th} order accurate \divb=0 relation for any numerical \bb field having a rthr^{th} order interpolation accuracy. Consistency arguments lead also to a proper formulation of the upwind procedures needed to integrate the induction equations, assuring the exact conservation in time of the divergence-free condition and the related continuity properties for the \bb vector components. As an application, a third order code to simulate multidimensional MHD flows of astrophysical interest is developed using ENO-based reconstruction algorithms. Several test problems to illustrate and validate the proposed approach are finally presented.Comment: 34 pages, including 14 figure
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