scholarly journals Estimation and Testing for Varying Coefficients in Additive Models With Marginal Integration

2006 ◽  
Vol 101 (475) ◽  
pp. 1212-1227 ◽  
Author(s):  
Lijian Yang ◽  
Byeong U Park ◽  
Lan Xue ◽  
Wolfgang Härdle
Keyword(s):  
Additive Models ◽  
Varying Coefficients ◽  
Marginal Integration

scholarly journals NONPARAMETRIC ESTIMATION AND TESTING OF INTERACTION IN ADDITIVE MODELS

2002 ◽  
Vol 18 (2) ◽  
pp. 197-251 ◽  
Author(s):  
Stefan Sperlich ◽  
Dag Tjøstheim ◽  
Lijian Yang
Keyword(s):  
Production Function ◽  
Test Procedure ◽  
Additive Model ◽  
Asymptotic Distributions ◽  
Additive Models ◽  
Local Power ◽  
Test Statistics ◽  
Interaction Terms ◽  
General Test ◽  
Marginal Integration

We consider an additive model with second-order interaction terms. Both marginal integration estimators and a combined backfitting-integration estimator are proposed for all components of the model and their derivatives. The corresponding asymptotic distributions are derived. Moreover, two test statistics for testing the presence of interactions are proposed. Asymptotics for the test functions and local power results are obtained. Because direct implementation of the test procedure based on the asymptotics would produce inaccurate results unless the number of observations is very large, a bootstrap procedure is provided, which is applicable for small or moderate sample sizes. Further, based on these methods a general test for additivity is developed. Estimation and testing methods are shown to work well in simulation studies. Finally, our methods are illustrated on a five-dimensional production function for a set of Wisconsin farm data. In particular, the separability hypothesis for the production function is discussed.

scholarly journals Marginal integration M-estimators for additive models

Test ◽  
2016 ◽  
Vol 26 (2) ◽  
pp. 231-260 ◽  
Author(s):  
Graciela Boente ◽  
Alejandra Martínez
Keyword(s):  
Additive Models ◽  
Marginal Integration

Relationships between temperature and Pacific hake distribution vary across latitude and life-history stage

2020 ◽  
Vol 639 ◽  
pp. 185-197 ◽  
Author(s):  
MJ Malick ◽  
ME Hunsicker ◽  
MA Haltuch ◽  
SL Parker-Stetter ◽  
AM Berger ◽  
...  
Keyword(s):  
Life History ◽  
Environmental Effects ◽  
Environmental Conditions ◽  
Vancouver Island ◽  
Additive Models ◽  
Life History Stage ◽  
Fish Stocks ◽  
Merluccius Productus ◽  
Multiple Dimensions ◽  
Effects Of Temperature

Environmental conditions can have spatially complex effects on the dynamics of marine fish stocks that change across life-history stages. Yet the potential for non-stationary environmental effects across multiple dimensions, e.g. space and ontogeny, are rarely considered. In this study, we examined the evidence for spatial and ontogenetic non-stationary temperature effects on Pacific hake Merluccius productus biomass along the west coast of North America. Specifically, we used Bayesian additive models to estimate the effects of temperature on Pacific hake biomass distribution and whether the effects change across space or life-history stage. We found latitudinal differences in the effects of temperature on mature Pacific hake distribution (i.e. age 3 and older); warmer than average subsurface temperatures were associated with higher biomass north of Vancouver Island, but lower biomass offshore of Washington and southern Vancouver Island. In contrast, immature Pacific hake distribution (i.e. age 2) was better explained by a nonlinear temperature effect; cooler than average temperatures were associated with higher biomass coastwide. Together, our results suggest that Pacific hake distribution is driven by interactions between age composition and environmental conditions and highlight the importance of accounting for varying environmental effects across multiple dimensions.

Association of the CD14 C159T and the Toll-like receptor 4 Asp299Gly polymorphisms with various phenotypes of asthma in adults from Crimea

2020 ◽  
Vol 41 (2) ◽  
pp. 134-140
Author(s):  
Yuriy Bisyuk ◽  
Andrew Dubovyi ◽  
Ilona DuBuske ◽  
Viktor Litus ◽  
Lawrence M. DuBuske
Keyword(s):  
Late Onset ◽  
Adult Population ◽  
Additive Models ◽  
Atopic Asthma ◽  
Control Group ◽  
Nucleotide Polymorphisms ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Single Nucleotide ◽  
Gender And Age

Background: This study assessed gene polymorphisms of the CD14 receptor (C-159T) and Toll-like receptor 4 (Asp299Gly) in a patient population in Crimea, Ukraine, stratified by clinical (early versus late onset; frequent versus occasional relapses; fixed versus reversible obstruction) and immunologic (atopic versus nonatopic; eosinophilic; neutrophilic or paucigranulocytic inflammation) subtype. Methods: Two polymorphisms, CD14 C-159T and TLR4 Asp299Gly, were assessed in 331 patients with asthma. The control group included 285 volunteers who were nonatopic. The single nucleotide polymorphisms were studied by using polymerase chain reaction with electrophoretic detection. Results: There were increased odds of asthma development in patients with the Asp299Gly TLR4 mutation compared with the general population underdominant odds ratio (OR) 1.52 [95% confidence interval (CI), 1.00‐2.32] and overdominant (OR 1.55 [95% CI, 1.01‐2.38]) models after adjustment for gender and age. In addition, mutations in this gene decreased the odds of nonatopic asthma in underdominant (OR 0.26 [95% CI, 0.07‐0.93]; p = 0.027), overdominant (OR 0.27 [95% CI, 0.07‐0.96]; p = 0.033), and log-additive models (OR 0.26 [95% CI, 0.07‐0.93]; p = 0.026) compared with the atopic subgroup after adjustment for gender, age, number of exacerbations, and type of airway inflammation. Allele frequencies for CD14 and TLR4 polymorphisms did not show statistical differences between the patients with asthma and the control subjects. Conclusion: CD14 C-159T polymorphisms were not associated with asthma in the adult population in Crimea. TLR4 Asp299Gly polymorphisms were associated with asthma and with decreased odds of nonatopic asthma compared with atopic asthma in the adult population in Crimea.

scholarly journals Joint Semantic Synthesis and Morphological Analysis of the Derived Word

2018 ◽  
Vol 6 ◽  
pp. 33-48 ◽  
Author(s):  
Ryan Cotterell ◽  
Hinrich Schütze
Keyword(s):  
Neural Networks ◽  
Recurrent Neural Networks ◽  
Probabilistic Model ◽  
Morphological Analysis ◽  
Semantic Representation ◽  
English Word ◽  
Word Formation ◽  
Additive Models ◽  
Segmentation Accuracy ◽  
Morphological Productivity

Much like sentences are composed of words, words themselves are composed of smaller units. For example, the English word questionably can be analyzed as question+ able+ ly. However, this structural decomposition of the word does not directly give us a semantic representation of the word’s meaning. Since morphology obeys the principle of compositionality, the semantics of the word can be systematically derived from the meaning of its parts. In this work, we propose a novel probabilistic model of word formation that captures both the analysis of a word w into its constituent segments and the synthesis of the meaning of w from the meanings of those segments. Our model jointly learns to segment words into morphemes and compose distributional semantic vectors of those morphemes. We experiment with the model on English CELEX data and German DErivBase (Zeller et al., 2013) data. We show that jointly modeling semantics increases both segmentation accuracy and morpheme F1 by between 3% and 5%. Additionally, we investigate different models of vector composition, showing that recurrent neural networks yield an improvement over simple additive models. Finally, we study the degree to which the representations correspond to a linguist’s notion of morphological productivity.

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