Human resource allocation management in multiple projects using sociometric techniques

This article describes a new application of key psychological concepts in the area of Sociometry for the selection of workers within organizations in which projects are developed. The project manager can use a new procedure to determine which individuals should be chosen from a given pool of resources and how to combine them into one or several simultaneous groups/projects in order to assure the highest possible overall work efficiency from the standpoint of social interaction. The optimization process was carried out by means of matrix calculations performed using a computer or even manually, and based on a number of new ratios generated ad-hoc and composed on the basis of indices frequently used in Sociometry.

Use of Information Visualization Methods Eliminating Cross Talk in Multiple Sensing Units Investigated for a Light-Addressable Potentiometric Sensor

The integration of nanostructured films containing biomolecules and silicon-based technologies is a promising direction for reaching miniaturized biosensors that exhibit high sensitivity and selectivity. A challenge, however, is to avoid cross talk among sensing units in an array with multiple sensors located on a small area. In this letter, we describe an array of 16 sensing units, of a light-addressable potentiometric sensor (LAPS), which was made with layer-by-Layer (LbL) films of a poly(amidomine) dendrimer (PAMAM) and single-walled carbon nanotubes (SWNTs), coated with a layer of the enzyme penicillinase. A visual inspection of the data from constant-current measurements with liquid samples containing distinct concentrations of penicillin, glucose, or a buffer indicated a possible cross talk between units that contained penicillinase and those that did not. With the use of multidimensional data projection techniques, normally employed in information Visualization methods, we managed to distinguish the results from the modified LAPS, even in cases where the units were adjacent to each other. Furthermore, the plots generated with the interactive document map (IDMAP) projection technique enabled the distinction of the different concentrations of penicillin, from 5 mmol L(-1) down to 0.5 mmol L(-1). Data visualization also confirmed the enhanced performance of the sensing units containing carbon nanotubes, consistent with the analysis of results for LAPS sensors. The use of visual analytics, as with projection methods, may be essential to handle a large amount of data generated in multiple sensor arrays to achieve high performance in miniaturized systems.

Improved score tests in symmetric linear regression models

The class of symmetric linear regression models has the normal linear regression model as a special case and includes several models that assume that the errors follow a symmetric distribution with longer-than-normal tails. An important member of this class is the t linear regression model, which is commonly used as an alternative to the usual normal regression model when the data contain extreme or outlying observations. In this article, we develop second-order asymptotic theory for score tests in this class of models. We obtain Bartlett-corrected score statistics for testing hypotheses on the regression and the dispersion parameters. The corrected statistics have chi-squared distributions with errors of order O(n(-3/2)), n being the sample size. The corrections represent an improvement over the corresponding original Rao`s score statistics, which are chi-squared distributed up to errors of order O(n(-1)). Simulation results show that the corrected score tests perform much better than their uncorrected counterparts in samples of small or moderate size.

Improved likelihood inference in Birnbaum-Saunders regressions

The Birnbaum-Saunders regression model is commonly used in reliability studies. We address the issue of performing inference in this class of models when the number of observations is small. Our simulation results suggest that the likelihood ratio test tends to be liberal when the sample size is small. We obtain a correction factor which reduces the size distortion of the test. Also, we consider a parametric bootstrap scheme to obtain improved critical values and improved p-values for the likelihood ratio test. The numerical results show that the modified tests are more reliable in finite samples than the usual likelihood ratio test. We also present an empirical application. (C) 2009 Elsevier B.V. All rights reserved.

Improved testing inference in mixed linear models

Mixed linear models are commonly used in repeated measures studies. They account for the dependence amongst observations obtained from the same experimental unit. Often, the number of observations is small, and it is thus important to use inference strategies that incorporate small sample corrections. In this paper, we develop modified versions of the likelihood ratio test for fixed effects inference in mixed linear models. In particular, we derive a Bartlett correction to such a test, and also to a test obtained from a modified profile likelihood function. Our results generalize those in [Zucker, D.M., Lieberman, O., Manor, O., 2000. Improved small sample inference in the mixed linear model: Bartlett correction and adjusted likelihood. Journal of the Royal Statistical Society B, 62,827-838] by allowing the parameter of interest to be vector-valued. Additionally, our Bartlett corrections allow for random effects nonlinear covariance matrix structure. We report simulation results which show that the proposed tests display superior finite sample behavior relative to the standard likelihood ratio test. An application is also presented and discussed. (C) 2008 Elsevier B.V. All rights reserved.

Determinantes do crescimento das gestoras independentes de recursos no Brasil, pós plano real

A dissertação objetivou identificar os principais determinantes que exercem influência no número de gestoras independentes de recursos de terceiros (Assets) em funcionamento no Brasil, um segmento que apresentou franco crescimento na última década. O método de análise empregado foi quantitativo, utilizando o modelo de regressão linear múltipla, e teve, como base de dados analisados, dados históricos de 15 variáveis macroeconômicas da economia brasileira. O período analisado contempla 14 anos (de 1994 a 2008). Dado o enfoque deste trabalho, considerou-se necessária uma revisão das principais mudanças ocorridas na economia e no setor financeiro do país, bem como seus reflexos nas taxas de juros, níveis de poupança, endividamento interno e externo e no setor bancário. Através da análise realizada foi possível perceber, através do emprego da análise de correlação, que as variáveis macroeconômicas são altamente relacionadas entre si, bem como identificar que as principais variáveis que têm impacto no mercado de Assets em funcionamento são: bancos em funcionamento no país; volume de recursos depositados em poupança e expectativa de inflação.

Centralized allocation in multiple markets

We study the problem of centralized allocation of indivisible objects in multiple markets. We show that the set of allocation rules that are group strategy-proof and Pareto-efficient are sequential dictatorships. Therefore, the solution of the joint al-location in multiple markets is significantly narrower than in the single-market case. Our result also applies to dynamic allocation problems. Finally, we provide conditions under which the solution of the single-market allocation coincides with the multiple-market case, and we apply this result to the study of the school choice problem with sibling priorities.

Influência da soma térmica e da chuva durante o desenvolvimento de laranjas-'Valência' e 'Natal' na relação entre sólidos solúveis e acidez e no índice tecnológico do suco

Este trabalho foi realizado com o objetivo de conhecer a influência que algumas variáveis meteorológicas exercem na razão entre sólidos solúveis totais e acidez total titulável (ratio) e no índice tecnológico dos frutos da primeira florada das laranjeiras-'Natal' e 'Valência', na região de Bebedouro-SP, mediante a utilização de métodos estatísticos de regressão. Foram utilizados dados de amostragens de rotina para o processamento industrial durante 4 anos, os quais permitiram desenvolver equações de regressão linear e quadrática, com a soma térmica (graus-dia) como variável independente, e de regressão múltipla, utilizando graus-dia e chuva como variáveis independentes. A equação de melhor ajuste para o índice tecnológico foi a quadrática, enquanto para o ratio a equação linear apresentou o melhor ajuste. A temperatura do ar, representada por graus-dia, foi a variável que exerceu maior influência nos indicadores de qualidade dos frutos.

Estimação da demanda de instalações elétricas de edificações com múltiplas unidades de consumo

This work aims to predict the total maximum demand of a transformer that will be used in power systems to attend a Multiple Unit Consumption (MUC) in design. In 1987, COSERN noted that calculation of maximum total demand for a building should be different from that which defines the scaling of the input protection extension in order to not overestimate the power of the transformer. Since then there have been many changes, both in consumption habits of the population, as in electrical appliances, so that this work will endeavor to improve the estimation of peak demand. For the survey, data were collected for identification and electrical projects in different MUCs located in Natal. In some of them, measurements were made of demand for 7 consecutive days and adjusted for an integration interval of 30 minutes. The estimation of the maximum demand was made through mathematical models that calculate the desired response from a set of information previously known of MUCs. The models tested were simple linear regressions, multiple linear regressions and artificial neural networks. The various calculated results over the study were compared, and ultimately, the best answer found was put into comparison with the previously proposed model

Parameter-dependent Lyapunov functions for state-derivative feedback control in polytopic linear systems

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fatores socioeconômicos contextuais associados à condição bucal de adolescentes no Brasil

Many surveys are conducted comparing oral health conditions with individual variables, such as socioeconomic and demographic factors. However, in the same way that individuals differ among themselves, the groups also have their own characteristics and the effects of this differentiation must be researched. Brazil, despite being one of the major economic powers of the world and shows an improvement in the average value of its health indicators, is also one of the most unequal and remains among the countries with the greatest health inequities. The purpose of this study was to investigate the importance of social determinants on the contextual level oral health among Brazilian adolescents, population not much researched by the literature. The research was made using an ecological approach in order to identify possible inequalities between cities and capitals. Using data from SBBrasil 2010 it was evaluated less common outcomes (loss of first molar, dental care index and T-Health) which provide information on the degree of morbidity of caries and health level of dental tissues, in addition to analyze the related services. The association of these oral health indicators with socioeconomic factors such as income, employment, education and inequality, collected from Census 2010, was analyzed by simple and multiple linear regressions. The study included the 27 state capitals and four clusters representing the municipalities of the country. It was possible to see better access to services in locations with better income distribution. However, the strong association of contextual factors related to poverty, low levels of education and poor housing and jobs with poorer levels of oral health in adolescents seems to overshadow the effects of income inequalities on dental caries in the country. In some locations, particularly within the North and Northeast, whichever one keeps dentistry mutilating, whose effects are already noticeable in its adolescent population. Access to restorative services in Brazil remains limited and unequal. The results of this study highlight the inequities in oral health in the country and show the need of the inclusion of new perspectives on the traditional approach of Preventive Dentistry and education models in Dentistry. Tackling health inequalities in oral health in the country requires the cooperation of various actors involved in the process and the inclusion of oral health in the context of overall health. The social determinants approach, as well as evaluating the distribution of oral diseases in the country and its inclusion in the context of overall health, should guide the implementation of programs and oral health practices in order to contribute to the reduction of inequalities