نتایج جستجو برای: compositional data

تعداد نتایج: 2424312  

2011
C. M. Pieters S. Besse J. Boardman B. Buratti L. Cheek R. N. Clark J. P. Combe D. Dhingra J. N. Goswami R. O. Green J. W. Head P. Isaacson R. Klima G. Kramer S. Lundeen E. Malaret T. McCord J. Mustard J. Nettles N. Petro C. Runyon M. Staid J. Sunshine L. A. Taylor K. Thaisen S. Tompkins J. Whitten

[1] High‐resolution compositional data from Moon Mineralogy Mapper (M) for the Moscoviense region on the lunar farside reveal three unusual, but distinctive, rock types along the inner basin ring. These are designated “OOS” since they are dominated by high concentrations of orthopyroxene, olivine, and Mg‐rich spinel, respectively. The OOS occur as small areas, each a few kilometers in size, tha...

2015
Marina Vives-Mestres Josep Daunis-i-Estadella

Nowadays, control of concentrations of elements is of crucial importance in industry. Concentrations are expressed in terms of proportions or percentages which means that they are compositional data (CoDa). CoDa are defined as vectors of positive elements that represent parts of a whole and usually add to a constant sum. Classical T 2 control chart is not appropriate for CoDa, for which is bett...

2005
Devin S. Johnson Jennifer A. Hoeting LeRoy Poff

We develop a model to relate a multivariate compositional response to a number of covariates. We propose a new graphical model, called the Random Effects Discrete Regression (REDR) model, which allows for examination of the complex conditional relationships between a set of covariates and multiple discrete response variables. Our approach offers a number of advantages over previous approaches a...

2006
Rashid Khan J. DeCanio

Sewage sludge is composed of organic and inorganic materials. The organic portion of the sludge is predominantly composed of C, H, ti, and S. On a dry-basis, the heating value of sludge is greater than that of oil shale or tar sand. The volatile matter content of dry sludge can be higher than that of the high volatile bituminous coal. Available correlations in the literature, developed for coal...

Journal: :Neurocomputing 2013
Huiwen Wang Liying Shangguan Junjie Wu Rong Guan

Compositional data, containing relative information, occur regularly inmany disciplines and practical situations. Multivariate statistics methods including regression analysis have been adopted to model compositional data, but the existing research is still scattered and fragmented. This paper contributes to modeling the linear regression relationship for compositional data as both dependent an...

2003
Linda T. Elkins-Tanton Nilanjan Chatterjee Timothy L. Grove

[1] Reanalysis of the Apollo 15 A, B, and C green glass beads from slide 15426,72, led to the discovery of patchy, highly vesicular glass rims adhering to beads. These rims are high in S and Ni and low in MgO, but otherwise compositionally similar to the green glasses. We find that these rims represent a unique melt composition that places constraints on lunar magmatic processes. Combining the ...

2014
Tuomas Virtanen Jort F. Gemmeke Bhiksha Raj Paris Smaragdis

Many classes of data are composed as constructive combinations of parts. By ”constructive” combination, we mean additive combination that do not result in subtraction or diminishment of any of the parts. We will refer to such data as “compositional” data. Typical examples include population or counts data, where the total count of a population is obtained as the sum of counts of subpopulations....

Journal: :Computational Statistics & Data Analysis 2012
J. A. Martín-Fernández Karel Hron Matthias Templ Peter Filzmoser Javier Palarea-Albaladejo

The log-ratio methodology represents a powerful set of methods and techniques for statistical analysis of compositional data. These techniques may be used for the estimation of rounded zeros or values below the detection limit in cases when the underlying data are compositional in nature. An algorithm based on iterative log-ratio regressions is developed by combining a particular family of isom...

Journal: :European Journal of Operational Research 2007
Huiwen Wang Qiang Liu Henry M. K. Mok Linghui Fu Wai Man Tse

Although Aitchison’s [Aitchison, J., 1986. The Statistical Analysis of Compositional Data, Chapman and Hall, London] method of logratio transformation of compositional data is widely used in various domains, it is limited by the assumption of a strict non-negativity of the components and the requirement of special treatments in practice of the zero components. We propose a dimension-reduction a...

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