Discriminant coordinates analysis for multivariate functional data

Abstract

One of the basic statistical methods of dimensionality reduction is analysis of discriminant coordinates given by Fisher (1936 Fisher, R. A. 1936. The use of multiple measurements in taxonomic problem. Annals of Eugenics 7 (2):179–88. doi:10.1111/j.1469-1809.1936.tb02137.x.[Crossref] , [Google Scholar]) and Rao (1948). The space of discriminant coordinates is a space convenient for presenting multidimensional data originating from multiple groups and for the use of various classification methods (methods of discriminant analysis). In the present paper, we adapt the classical discriminant coordinates analysis to multivariate functional data. The theory has been applied to analysis of textural properties of apples of six varieties, measured over a period of 180?days, stored in two types of refrigeration chamber.     

Regression Methods for Combining Multiple Classifiers

As no single classification method outperforms other classification methods under all circumstances, decision-makers may solve a classification problem using several classification methods and examine their performance for classification purposes in the learning set. Based on this performance, better classification methods might be adopted and poor methods might be avoided. However, which single classification method is the best to predict the classification of new observations is still not clear, especially when some methods offer similar classification performance in the learning set. In this article we present various regression and classical methods, which combine several classification methods to predict the classification of new observations. The quality of the combined classifiers is examined on some real data. Nonparametric regression is the best method of combining classifiers.     

Call for papers: ESPE 1992

Call for papers: ESPE 1992     

Insulin resistance,oxidative stress markers and the blood antioxidant system in overweight elderly men

The purpose of the study was to examine in the blood of overweight men aged from 62 to 83 years, the relationships between age and insulin resistance, selected parameters of the oxidative stress, and the antioxidant defense system. The population studied was divided into two groups: the group ‘young-old’ consisted of men aged 62 to 74 years old, and the group ‘old-old’– of men aged between 75 and 83 years. The total antioxidative status (TAS) and concentrations of thiobarbituric acid reactive substances (TBARS) were measured in the blood plasma. In the serum samples, the levels of antibodies against oxidized LDL (oLAB), glucose, total cholesterol, HDL-cholesterol, triglycerides and insulin were measured. Homeostasis Model Assessment of Insulin Resistance (HOMA_IR) was calculated. Concentration of reduced glutathione (GSH) and glutathione peroxidase activity (GPx) were determined in the red blood cells hemolysate. The results of the study did not show significant differences between groups investigated with respect to concentrations of TBARS, TAS, GSH and GPx. However, significantly higher concentrations of glucose and antibodies against oxLDL (p < 0.05) were observed in the group of men over 74 years old in comparison to the group of ‘young-old’ men. It was indicated that the increased insulin resistance and hyperglycemia in elderly men are related to body mass and that they cause intensified oxidative modifications of LDL.     

Forecasting environmental migration to the United Kingdom: an exploration using Bayesian models

Over the next 50 years, the potential impact of environmental change on human livelihoods could be considerable, with one possible consequence being increased levels of human mobility. This paper explores how uncertainty about the level of immigration to the United Kingdom as a consequence of environmental factors elsewhere may be forecast using a methodology involving Bayesian models. The conceptual understanding of forecasting is advanced in three ways. First, the analysis is believed to be the first time that the Bayesian modelling approach has been attempted in relation to environmental mobility. Second, the paper considers the expediency of this approach by comparing the responses to a Delphi survey with conventional expectations about environmental mobility in the research literature. Finally, the values and assumptions of the expert evidence provided in the Delphi survey are interrogated to illustrate the limited set of conditions under which forecasts of environmental mobility, as set out in this paper, are likely to hold.     

Fiscal harmonization in view of the Euro adoption: Economic implications for Poland

In this paper, we investigate the ex ante effects of fiscal policy harmonization that might be necessary for the adoption of the common currency on economic growth in Poland using a neoclassical dynamic two-sector general equilibrium model. We study two fiscal policy scenarios. In the first one, we adjust all taxes to German and EU-27 levels, respectively, while in the second one, we change only consumption taxes to German and EU-27 levels. We find that in the first scenario, the current Polish taxes yield the highest rate of growth due to lower capital taxation. However, in the second scenario, German and EU-27 taxes yield the highest rate of growth due to the lower consumption tax on capital-intensive good. From a policy perspective, our results suggest that fiscal policy with lower taxes on capital and capital-intensive goods can generate a higher rate of growth in the long-run. In the case of fiscal harmonization, our findings propose adopting only German or EU-27 consumption tax structure into the Polish tax system.     

Management innovation,pro-innovation organisational culture and enterprise performance: testing the mediation effect

The interest in management innovation (MI) is growing and the conviction about its significant role in boosting an enterprise’s competitive advantage and performance has recently gained ground. The studies on MI and its relationships with enterprise performance, which are relatively scarce in literature, indicate the complexity of these relationships. This inspired us to propose the management innovation construct and its operationalisation, which allowed for the empirical verification of the relationships between management innovation and enterprise performance. Simultaneously, we adopted the hypothesis on the mediating role of pro-innovation organisational culture. The aim of this article, therefore, is to study the relationships between MI and enterprise performance as well as to determine what role is played by pro-innovation organisational culture in these relationships. In order to do that, we conducted a survey of 301 companies based in Poland. Our research results confirmed the existence of relationships between management innovation and enterprise performance in the survey sample, although they were not very strong. Additionally, the hypothesis about the mediating role of organisational culture was also partially supported. The results of our study enrich the knowledge about the role of MI in stimulating enterprise performance and the role of pro-innovation organisational culture. We also discuss the implications for further research and management practice.