472 research outputs found

    Does Data Splitting Improve Prediction?

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    Data splitting divides data into two parts. One part is reserved for model selection. In some applications, the second part is used for model validation but we use this part for estimating the parameters of the chosen model. We focus on the problem of constructing reliable predictive distributions for future observed values. We judge the predictive performance using log scoring. We compare the full data strategy with the data splitting strategy for prediction. We show how the full data score can be decomposed into model selection, parameter estimation and data reuse costs. Data splitting is preferred when data reuse costs are high. We investigate the relative performance of the strategies in four simulation scenarios. We introduce a hybrid estimator called SAFE that uses one part for model selection but both parts for estimation. We discuss the choice to use a split data analysis versus a full data analysis

    Backscoring in principal coordinates analysis

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    The Exact and Asymptotic Distributions of Cramérâ Von Mises Statistics

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146839/1/rssb02077.pd

    Time series forecasting with neural networks: a comparative study using the air line data

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73285/1/1467-9876.00109.pd

    Does data splitting improve prediction

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    Modeling continuous shape change for facial animation

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    The movement of landmarks on the human face can be recorded in 3D using motion capture equipment. We describe methods for the analysis of data collected on groups of subjects with a view to describing and assessing the differences between the facial motions of those groups. We focus on the smile motion in particular. The methods presented can be used more generally for continuous shape change data.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47977/1/11222_2004_Article_5273891.pd

    Modelling three-dimensional trajectories by using BÉzier curves with application to hand motion

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72561/1/j.1467-9876.2007.00592.x.pd

    Regression for non-Euclidean data using distance matrices

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    Local attitudes toward Apennine brown bears: Insights for conservation issues

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    Human-carnivore coexistence is a multi-faceted issue that requires an understanding of the diverse attitudes and perspectives of the communities living with large carnivores. To inform initiatives that encourage behaviors in line with conservation goals, we focused on assessing the two components of attitudes (i.e., feelings and beliefs), as well as norms of local communities coexisting with Apennine brown bears (Ursus arctos marsicanus) for a long time. This bear population is under serious extinction risks due to its persistently small population size, which is currently confined to the long-established protected area of Abruzzo, Lazio and Molise National Park (PNALM) and its surrounding region in central Italy. We interviewed 1,611 residents in the PNALM to determine attitudes and values toward bears. We found that support for the bear's legal protection was widespread throughout the area, though beliefs about the benefits of conserving bears varied across geographic administrative districts. Our results showed that residents across our study areas liked bears. At the same time, areas that received more benefits from tourism were more strongly associated with positive feelings toward bears. Such findings provide useful information to improve communication efforts of conservation authorities with local communities
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