50,477 research outputs found

    TEMPUS: A proposal for international time transfer and precision tracking satellite

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    Very Long Baseline Interferometry (pulsars), Television relay via satellite, portable clocks, Navigation Technology Satellite, and Loran C are described and compared

    A decision-theoretic approach for segmental classification

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    This paper is concerned with statistical methods for the segmental classification of linear sequence data where the task is to segment and classify the data according to an underlying hidden discrete state sequence. Such analysis is commonplace in the empirical sciences including genomics, finance and speech processing. In particular, we are interested in answering the following question: given data yy and a statistical model π(x,y)\pi(x,y) of the hidden states xx, what should we report as the prediction x^\hat{x} under the posterior distribution π(xy)\pi (x|y)? That is, how should you make a prediction of the underlying states? We demonstrate that traditional approaches such as reporting the most probable state sequence or most probable set of marginal predictions can give undesirable classification artefacts and offer limited control over the properties of the prediction. We propose a decision theoretic approach using a novel class of Markov loss functions and report x^\hat{x} via the principle of minimum expected loss (maximum expected utility). We demonstrate that the sequence of minimum expected loss under the Markov loss function can be enumerated exactly using dynamic programming methods and that it offers flexibility and performance improvements over existing techniques. The result is generic and applicable to any probabilistic model on a sequence, such as Hidden Markov models, change point or product partition models.Comment: Published in at http://dx.doi.org/10.1214/13-AOAS657 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Towards a More Inclusive Music Education: Experiences of LGBTQQIAA Students in Music Teacher Education Programs Across Pennsylvania

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    During the past decade, the field of music education has seen an increase in the amount of scholarship surrounding LGBTQ studies in music teaching and learning. For example, the University of Illinois hosted three symposia for the field of music education dedicated to LGBTQ studies (2010, 2012, 2016), and proceedings from these symposia were published in three separate issues of the of the Bulletin of the Council for Research in Music Education (2011, 2014, 2016). Other notable scholarship has been published in Action, Criticism, and Theory for Music Education (Gould 2005); the Music Educators Journal (Bergonzi, 2009; Carter, 2011; McBride, 2016); the Journal of Research in Music Education (Carter, 2013; Nicholas, 2013); and UPDATE: Applications of Research in Music Education (Garrett, 2012). (excerpt

    Why Do REITs Repurchase Stock? Extricating the Effect of Managerial Signaling in Open Market Share Repurchase Announcements

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    This paper explores the effect of stock repurchase announcements on equity returns for publicly traded real estate investment trusts (REITs). In addition to providing analysis of the corporate decision to repurchase shares, the study of share repurchases in the context of REITs provides a novel opportunity to disentangle the impact of competing theories for the abnormal returns observed around repurchase announcements. Prior literature advances six hypotheses to explain the stock price reaction associated with repurchases. Given that the theories all predict the same stock price reaction, existing studies are unable to disentangle the competing hypotheses. The intent of this research is to extricate the signaling hypothesis from the competing explanations to determine whether the managerial signaling hypothesis is a credible explanation for the abnormal returns observed around share repurchase announcements. After controlling for relevant economic variables, we provide evidence for the efficacy of the managerial signaling hypothesis.

    Application and sensitivity investigation of Fourier transforms for microwave radiometric inversions

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    Existing microwave radiometer technology now provides a suitable method for remote determination of the ocean surface's absolute brightness temperature. To extract the brightness temperature of the water from the antenna temperature equation, an unstable Fredholm integral equation of the first kind was solved. Fast Fourier Transform techniques were used to invert the integral after it is placed into a cross-correlation form. Application and verification of the methods to a two-dimensional modeling of a laboratory wave tank system were included. The instability of the Fredholm equation was then demonstrated and a restoration procedure was included which smooths the resulting oscillations. With the recent availability and advances of Fast Fourier Transform techniques, the method presented becomes very attractive in the evaluation of large quantities of data. Actual radiometric measurements of sea water are inverted using the restoration method, incorporating the advantages of the Fast Fourier Transform algorithm for computations

    Elastic and plastic stresses at weld sinkages and other discontinuities in pressure vessels

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    Mismatch and weld sinkage problems of pressure vessel geometric discontinuities studied in design graphs and test progra

    The metal finds and their implications

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    Major interdisciplinary study of metal artefacts from major Norse site in Orkney
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