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65 647 (0,17s) •

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Model-based replacement of rounded zeros in compositional data: Classical and robust approaches

, the equivalence of the method based on additive and isometric log-ratio transformationsThe log-ratio methodology represents a powerful set of methods and techniques the underlying data are compositional ...

BB - Aplikovaná statistika, operační výzkum

  • 2012
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  • Jx
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Result

A new method for correlation analysis of compositional (environmental) data – a worked example

analysis, for which the data need to be appropriately log-ratio transformed. A newapproach based on the isometric log-ratio (ilr) transformation, leading to so-called analysis based on log

Statistics and probability

  • 2017
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  • Jimp
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Result

Practical aspects of log-ratio coordinate representations in regression with compositional response

orthonormal coordinates and centred log-ratio coordinates can be utilized to simplify with orthonormal and centred log-ratio coordinates are presented. Further we discuss squared error (MSE) for orthonormal coordi...

BA - Obecná matematika

  • 2016
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Result

Covariance-based variable selection for compositional data

Omitting variables in compositional data analysis may lead to a substantial change in results from that of multivariate statistical analysis. In particular, this is the case for principal component analysis and the compositional biplot, where both th...

BB - Aplikovaná statistika, operační výzkum

  • 2013
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  • Jx
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Result

Bayesian-multiplicative treatment of count zeros in compositional data sets

techniques based on the log-ratio methodology are appropriate in those cases where with a larger number of trials or with a different sampling design. Because the log-ratio transformations require data wi...

BA - Obecná matematika

  • 2015
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  • Jx
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Result

Correlation analysis for compositional data

Compositional data need a special treatment prior to correlation analysis. In this paper we argue why standard transformations for compositional data are not suitable for computing correlations, and why the use of raw or log-tra...

BA - Obecná matematika

  • 2009
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  • Jx
Result

Separating provenance and palaeoclimatic signals from particle size and geochemistry of loess-palaeosol sequences using log-ratio transformation: Central European loess belt, Czech Republic

analysis, including log-ratio transformation and scalar-on-function regression, can analysed in this study. Centered log-ratio transformation was applied to the key) distribution. Centered lo...

Geology

  • 2021
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  • Jimp
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Result

Simplicial regression. The normal model

Regression models with compositional response have been studied from the beginning of the log-ratio approach for analysing compositional data. These early approaches suggested the statistical hypothesis of logistic-normality of the ...

BB - Aplikovaná statistika, operační výzkum

  • 2011
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  • Jx
Result

Robust biomarker identification in a two-class problem based on pairwise log-ratios

A new method, robust Pair-wise Log-Ratios (rPLR), is proposed can cope with the size effect problem, since it is based on log-ratios between the values of all pairs of variables. rPLR makes use of the variance of p...

Statistics and probability

  • 2017
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  • Jimp
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Result

Total least squares solution for compositional data using linear models

in variables, calibration problem), performed after an appropriate log-ratio transformation...

BA - Obecná matematika

  • 2010
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  • Jx
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