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...

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...

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...

This dissertation presents a framework for the application of compositional modularity a module model that facilitates extensive reuse of highly decomposed software Compositional modularity supports not only the traditional notions of program decomposition and encapsulation but also e ective mechanisms for module recom position Based on a previously developed model a suite of operators individu...

The aim of this contribution is to show how the R-package robCompositions can be applied to estimate missing values in compositional data. Two procedures are summarized, one of them being highly stable also in presence of outlying observations. Measures for information loss are presented, and it is demonstrated how they can be applied. Moreover, we introduce new diagnostic tools that are useful...

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...

Social network items have been included in several cross-national surveys (e.g., Generations and Gender Programme, European Quality of Life Survey, International Social Survey Programme). In these surveys, several different methods and questionnaire items are applied to measure similar or identical constructs. These methods are the name generator method and the simplified role relation method. ...

[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 ...

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....

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...