19,567 research outputs found

    A stronger topology for the Brownian web

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    We propose a metric space of coalescing pairs of paths on which we are able to prove (more or less) directly convergence of objects such as the persistence probability in the (one dimensional, nearest neighbor, symmetric) voter model or the diffusively rescaled weight distribution in a silo model (as well as the equivalent output distribution in a river basin model), interpreted in terms of (dual) diffusively rescaled coalescing random walks, to corresponding objects defined in terms of the Brownian web.Comment: 22 page

    Method of tracing contour patterns for use in making gradual contour resin matrix composites

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    The invention relates to methods for making alminate patterns for a resin matrix composite structural component. A sheet of paper is temporarily adhered to a model of the structrual component. A pen is positioned on the paper with a spindle touching the model surface opposite the pen. The pen and spindle are moved along the path that maintains the aforementioned contacts. The resulting line traced on paper is a model constant-thickness locus and provides a pattern for a single lamination of resin-impregnated fabric. The steps are repeated to make other patterns and each time the steps are repeated the distance between the tracer and the spindle is changed to correspond to the thickness of a lamination

    Youth and Unions

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    [Excerpt] Following a suggestion from the Cornell ILR Labor Advisory Counsel in early 2009 Cornell ILR began studying the relationships between young workers and unions. Marlena Fontes, a Cornell student, worked with Cornell Extension Faculty Ken Margolies and others during the summer of 2009 on the study. The study is based on a literature review, survey research, observations and focus groups. The report provides a glimpse into the issues that are facing young people and unions and how unions are seeking to organize and involve young workers and members. The table on page 9 summarizes the survey research conducted by Ms. Fontes and two other Cornell summer Fellows

    A framework for list representation, enabling list stabilization through incorporation of gene exchangeabilities

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    Analysis of multivariate data sets from e.g. microarray studies frequently results in lists of genes which are associated with some response of interest. The biological interpretation is often complicated by the statistical instability of the obtained gene lists with respect to sampling variations, which may partly be due to the functional redundancy among genes, implying that multiple genes can play exchangeable roles in the cell. In this paper we use the concept of exchangeability of random variables to model this functional redundancy and thereby account for the instability attributable to sampling variations. We present a flexible framework to incorporate the exchangeability into the representation of lists. The proposed framework supports straightforward robust comparison between any two lists. It can also be used to generate new, more stable gene rankings incorporating more information from the experimental data. Using a microarray data set from lung cancer patients we show that the proposed method provides more robust gene rankings than existing methods with respect to sampling variations, without compromising the biological significance

    Time-Periodic Solutions of the Burgers Equation

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    We investigate the time periodic solutions to the viscous Burgers equation ut−μuxx+uux=fu_t -\mu u_{xx} + uu_x = f for irregular forcing terms. We prove that the corresponding Burgers operator is a diffeomorphism between appropriate function spaces

    Estimating Learning Models with Experimental Data

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    We study the statistical properties of three estimation methods for a model of learning that is often tted to experimental data: quadratic deviation measures without unobserved heterogeneity, and maximum likelihood with and without unobserved heterogeneity. After discussing identi cation issues, we show that the estimators are consistent and provide their asymptotic distribution. Using Monte Carlo simulations, we show that ignoring unobserved heterogeneity can lead to seriously biased estimations in samples which have the typical length of actual experiments. Better small sample properties are obtained if unobserved heterogeneity is introduced. That is, rather than estimating the parameters for each individual, the individual parameters are considered random variables, and the distribution of those random variables is estimated
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