Symmetrical and Non-Symmetrical Variants of Three-Way Correspondence Analysis for Ordered Variables

In the framework of multi-way data analysis, this paper presents symmetrical and non-symmetrical variants of three-way correspondence analysis that are suitable when a three-way contingency table is constructed from ordinal variables. In particular, such variables may be modelled using general recurrence formulae to generate orthogonal polynomial vectors instead of singular vectors coming from one of the possible three-way extensions of the singular value decomposition. As we shall see, these polynomials, that until now have been used to decompose two-way contingency tables with ordered variables, also constitute an alternative orthogonal basis for modelling symmetrical, non-symmetrical associations and predictabilities in three-way contingency tables. Consequences with respect to modelling and graphing will be highlighted

Variants of Simple Correspondence Analysis

This paper presents a description of the R package CAvariants. It performs six variants of correspondence analysis on a two-way contingency table. The main function that shares the same name as the package - CAvariants - allows the user to choose (via a series of input parameters) from six different correspondence analysis procedures. These include the classical approach to (symmetrical) correspondence analysis, singly ordered correspondence analysis, doubly ordered correspondence analysis, non symmetrical correspondence analysis, singly ordered non symmetrical correspondence analysis and doubly ordered non symmetrical correspondence analysis. The code provides the flexibility for constructing either a classical correspondence plot or a biplot graphical display. It also allows the user to consider other important features that allow for one to assess the reliability of the graphical representations, such as the inclusion of algebraically derived elliptical confidence regions. This paper provides R functions that elaborates more fully on the code presented in Beh and Lombardo (2014)

A Geneaology of Correspondence Analysis: Part 2 - The Variants

In 2012, a comprehensive historical and genealogical discussion of correspondence analysis was published in Australian and New Zealand Journal of Statistics. That genealogy consisted of more than 270 key books and articles and focused on an historical development of the correspondence analysis,a statistical tool which provides the analyst with a visual inspection of the association between two or more categorical variables. In this new genealogy, we provide a brief overview of over 30 variants of correspondence analysis that now exist outside of the traditional approaches used to analysethe association between two or more categorical variables. It comprises of a bibliography of a more than 300 books and articles that were not included in the 2012 bibliography and highlights the growth in the development ofcorrespondence analysis across all areas of research

Bootstrap selection of Multivariate Additive PLS Spline models

EnMultivariate Additive PLS Splines, in short MAPLSS, are Partial Least-Squares models that study the dependence of a set of responses on spline transformations of the predictor variables which permit to capture additively non linear main effects and interactions. The aim of this paper is to present a way of selecting MAPLSS models through an adaptive incremental selection of training samples by a bootstrap procedure. This approach is attractive in the case of expensive data thus implying to construct efficient models based on small training data sets

Identity and Labor Market Outcomes of Immigrants

This paper explores the relationship between social identity and labor market outcomes of immigrants. Using survey data from Italy, we provide robust evidence that immigrants with stronger feelings of belonging to the societies of both the host and home country have higher employment rates, while those who exclusively identify with the host country culture do not have a net occupational advantage. Analysis of the potential mechanisms suggests that, although simultaneous identification with host and home country groups can be costly, the positive effect of multiple social identities is especially triggered by the enlarged information transmission and in-group favoritism that identification with, and membership of, extended communities ensure

Silicon Quasi‐One‐Dimensional Nanostructures for Photovoltaic Applications

Thanks to the silicon abundance, stability, non-toxicity and well known electronic properties, Si based solar cells have represented the leading actors in the photovoltaic market and future projections confirm this predominance. However, half of the module cost is due to the material consumption and processing. In order to decrease the costs, a cut in the Si consumption must be operated, with consequent decrement in the optical absorption, generated current and device efficiency. To keep the performance level, a proper Si surface design with the objective to trap the light, has been developed. One of the most popular approaches is to use silicon nanowires embedded in the solar cell emitter where they play the role of optically and electrically active layer, thanks to their excellent optical absorption properties. However, also another material has been the terminus of the light-trapping materials, the silicon nanoholes. Their mechanical robustness is superior, making their integration inside the cell easier and cost-effective. The review will bring about all of the most common methods to fabricate these two types of nanostructures when used for solar cells applications, their optical properties and some critical aspects related to their high surface to volume ratio which modify the recombination processes

A nonlinear generalization of Arbitrage Pricing Theory

EnArbitrage Pricing Theory (APT) leads good estimates of expected utility stock returns by means of k factors. Notwithstanding initial skepticism the idea of using multiple risk factors to explain the relationship between expected return and asset risk has been winning. In literature the APT has been seen as a generalization of single risk factor approach of Capital Asset Pricing Model (CAPM). The APT provides a better indication of asset risk and a better estimate of expected return than CAPM does. In this paper we propose a generalization of APT to non-linear case. In order to study the relationships which occur between return and multiple risk factors, we propose non-linear principal components. To find justifications for embracing a more complicated model than traditional APT we evaluate the consistency of results by known real data

Geophysical measurements for site response investigation : preliminary results on the island of Malta

The main goal of this study is to investigate the dynamic properties of main lithotypes outcropping on the island of Malta and to evaluate the general features of the local seismic response through the combined use of geophysical methods based on Rayleigh waves and horizontal to vertical noise spectral ratios. These kind of studies have unfortunately never been undertaken in Malta and, therefore, no shear wave velocity values and fundamental frequency of outcropping lithotypes have been published. The proposed preliminary results represent a valid set of data useful for evaluating seismic hazard and risk for the Maltese islands. Even if the seismic activity around the archipelago is generally of low to moderate magnitude the islands in the past were struck by large events in Sicily and the Hellenic arc resulting in considerable damage.peer-reviewe

The Rise and Fall of Family Firms in the Process of Development

This paper explores the causes and the consequences of the evolution of family firms in the growth process. The theory suggests that in early stages of development, valuable family specific human capital stimulated the productivity of family firms and the development process. However, in light of the rise in the importance of managerial talents for firms' productivity in later stages, family firms generated a misallocation of managerial talents, curbing productivity and economic growth. Evidence supports the dual impact of family firms in the development process and the role of socio-cultural characteristics in observed variations in the productivity of family firms