An empirical comparison of two approaches for CDPCA in high-dimensional data

Statistical Methods & Applications - Modified principal component analysis techniques, specially those yielding sparse solutions, are attractive due to its usefulness for interpretation...     

Ridge Regression and Generalized Maximum Entropy: An improved version of the Ridge–GME parameter estimator

In this article, the Ridge–GME parameter estimator, which combines Ridge Regression and Generalized Maximum Entropy, is improved in order to eliminate the subjectivity in the analysis of the ridge trace. A serious concern with the visual inspection of the ridge trace to define the supports for the parameters in the Ridge–GME parameter estimator is the misinterpretation of some ridge traces, in particular where some of them are very close to the axes. A simulation study and two empirical applications are used to illustrate the performance of the improved estimator. A MATLAB code is provided as supplementary material.     

Regularization with Maximum Entropy and Quantum Electrodynamics: The Merg(E) Estimators

It is well-known that under fairly conditions linear regression becomes a powerful statistical tool. In practice, however, some of these conditions are usually not satisfied and regression models become ill-posed, implying that the application of traditional estimation methods may lead to non-unique or highly unstable solutions. Addressing this issue, in this paper a new class of maximum entropy estimators suitable for dealing with ill-posed models, namely for the estimation of regression models with small samples sizes affected by collinearity and outliers, is introduced. The performance of the new estimators is illustrated through several simulation studies.     

Interwoven migration narratives: identity and social representations in the Lusophone world

This article provides an exploratory analysis of the life narratives of migrants in the Portuguese-speaking world. By interweaving the life experiences of eight participants in three thematic clusters – ‘shared past’, language and sense of community – we propose a critique of the deep-seated idea of the Lusophone space as a community constructed by the harmonious conviviality of different countries and people. Drawing on contributions from cultural studies, social psychology, anthropology and sociology, we first aim to give voice to the human subjects who embark on migrations and then to understand how the engendered process of identity construction is framed by their social world, simultaneously reframing it. Thus, we aim at shedding light on the ways in which aspects of the political discourses on Lusophony are used (and are instrumental) to the migrants’ identity narrative (re)construction.     

Avian biotic homogenization driven by airport-affected environments

Urban Ecosystems - Building and operating airports are human activities associated with adverse changes in the natural environment, resulting in threats to the biodiversity in airport surroundings....     

Macroergonomic intervention for work design improvement and raw materials waste reduction in a small footwear components company in Rio Grande do Sul-Brazil

This article presents a macroergonomic intervention carried out in a small footwear components company located in the state of Rio Grande do Sul, Brazil. The company's demand was related to the waste of the expensive raw-material (thermoplastic polyurethane or TPU) used to manufacture the components (high heels pegs). According to the managerial staff, the waste was workers responsibility due to the craft characteristic of the process. A participative method was used to evaluate the problems, propose and implement solutions, as well as evaluate their impact on the workers and the Company. Improvements in the work conditions resulted in increase of workers' satisfaction with the work and in 31.5% waste reduction.     

Accidents related to the use of products and services in the city of São Luis, Brazil

This article presents a study on the accidents related to the use of products and services, as recorded at two emergency hospitals at the city S?o Luís, Brazil. The goal of the study was to evaluate the main types and causes of unintentional accidents as well as the more frequent injuries for further improvement of products and services. The study evaluated the victims profile (gender and age), the circumstances (activity, local and time) that lead to the accidents and the type of resulted injury. Non-parametric statistics showed that 83.64% of the accidents were related to products (57.6% of them being consumer products) and 8.6% are related to maintenance services. 57.6% of the victims were children under 15 years old, and 58.4% were male. 50.2% of accidents occurred at home, more often (44.7%) in the afternoon. The most common injury was musculoesqueletal (48.6%), 49.0% being cranioencephalic trauma and 15.2% fractures.     

Wood, management and dust: analysis of the Context of Production of Goods and Services (CPGS) of an academic woodwork

The CGPS of the woodwork of a public university was observed and analyzed. Apart from what is usual in the field of Ergonomics' studies, it is an academic context, where there is not a direct implication of profit, productivity and clientele. The group tried to sever negative and broadcasted opinions about the place by analyzing it from a different point of view. This work was considered relevant, since it is related to neglect of education and citizenship. For this case study, it was used the Ergonomics Analysis of Work with all workers at the woodwork. The instruments were documental analysis, free observation with photographic register, semi-structured interview with the workers and survey Pontos de Verica??o Ergon?mica. The results are presented by the perspective of work conditions, work organization and social-professional work relationship. The present study brought several contributions, such as the complementation of the theory and a new perspective of the analyzed context, o bserved now by the worker's point of view. As a result of the analysis, it was questioned about citizenship and the neglect with the public good, even though the relevant social role that this academic institution plays. In conclusion, the group suggests some proposals that modify positively the CGPS of this academic woodwork.     

Macroergonomic analysis of two different work organizations in a same sector of a luminary manufacturer

This article presents the analysis of the effect of two different types of work organization (the traditional and a new mechanized, more segmented one) in the packing sector of a luminary manufacturing company in Curitiba, Brazil. A macroergonomic analysis was conducted to evaluate the workers satisfaction with the job; the possible associated postural risk, the level of body pain/discomfort and to compare the two models (traditional and mechanized). The mechanized model showed to involve higher postural risk, to generate more pain and less satisfaction, even in relation to the temperature, illumination, uniform and salary, which are the same for the two groups. Excluding job rotation that was well evaluated and should be adopted for all workers, the new model proved to be worse than the traditional although it also needs improvements.     

A General Class of Estimators for the Linear Regression Model Affected by Collinearity and Outliers

In this article, a general class of estimators for the linear regression model affected by outliers and collinearity is introduced and studied in some detail. This class of estimators combines the theory of light, maximum entropy, and robust regression techniques. Our theoretical findings are illustrated through a Monte Carlo simulation study.