967 resultados para Least-Squares estimation


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Este estudo analisa a contribuição da centralidade em redes de negócios, na elevação da complexidade da estrutura organizacional de supermercados e os possíveis efeitos dessa mudança no processo decisório empreendedor. Causation e Effectuation são processos decisórios distintos que possuem sua hora adequada de utilização. Porém, faltam estudos sobre quando os empreendedores utilizam tais processos em ambientes de redes interorganizacionais. Para preencher esse gap, a pesquisa centra-se na tipologia de rede de cooperação associativa (BALESTRIN; VARGAS, 2004; BALESTRIN; VERSCHOORE, 2008). O referencial teórico foi construído a partir dos conceitos de centralidade (FREEMAN, 1979; WASSERMAN; FAUST, 1994), laços relacionais (BURT, 1992; GRANOVETTER, 1973), complexidade da estrutura organizacional (HALL, 2004), e dos processos decisórios de Causation e Effectuation (SARASVATHY, 2001a). Inicialmente, os dados foram coletados de forma indutiva em seis casos de micros e pequenos supermercados em redes de negócios no estado do Ceará. Após analisar o conteúdo de cada caso, o pesquisador procedeu uma Análise Qualitativa Comparativa (Qualitative Comparative Analysis – QCA). As condições necessárias à adoção dos processos decisórios foram: a) a centralidade contribui para elevar a complexidade da estrutura organizacional e/ou adoção de mecanismos de controle gerencial, quando as relações são conduzidas mais por laços sociais do que por laços estratégicos; b) empreendedores adotam Effectuation e Causation independentemente da complexidade da estrutura organizacional dos supermercados. Um novo achado foi que, além dos empreendedores novatos, os experientes também variam o uso de Effectuation e Causation no início dos novos empreendimentos. Mas ao longo do tempo, ao implementarem mecanismos de controle gerencial, eles tendem a reduzir a utilização de algumas práticas efetuais, como as capacidades de experimentar e aceitar riscos e perdas. Dados complementares foram coletados e testes foram realizados por meio de Modelagem de Equações Estruturais (MEE) baseada em partial least squares (PLS). Os resultados confirmaram que: c) os laços sociais exercem mais influência que os estratégicos, na transformação da estrutura organizacional dos supermercados; d) essa transformação influencia positivamente na implantação de mecanismos de controle gerencial; e) supermercados com mecanismos de controle gerencial terão empreendedores mais propensos a adotarem o processo de Causation, e menos propensos a experimentar e aceitar riscos e perdas. Os resultados contribuem para entender quando as relações geradas em redes de cooperação, afetam a fundação e o crescimento de pequenas empresas, e onde ocorre a evolução do comportamento decisório empreendedor no tempo. De forma prática, a pesquisa demonstra aos micros e pequenos empreendedores que eles não precisam gerar muitas relações para desenvolverem seus negócios, ou seja, a posição relativa do supermercado na rede não é importante, desde que os laços sociais estejam ativos e haja engajamento nas atividades das associações. Também ensina que os empreendedores tendem a desenvolver o raciocínio causal em redes de negócios.

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O mercado de securitização através de Fundos de Investimento em Direitos Creditórios (FIDCs) no Brasil ainda não é tão desenvolvido quando comparado aos mercados internacionais. O desenvolvimento desse mercado facultaria a bancos e empresas acesso a fontes de financiamento além da sua geração de caixa ou da emissão de novas ações. Bancos e empresas devem manter a busca por formas alternativas de financiamento, obtendo, assim, diversificação de suas fontes de recursos. O objetivo desse trabalho é avaliar como as características dos FIDCs afetam a taxa de captação de suas cotas sênior. Para isso foram avaliadas 151 séries de cotas, emitidas entre 2002 e 2014. Na análise foram usadas análises multivariadas através da regressão linear múltipla, usando o método de Mínimos Quadrados Ordinários (MQO), para avaliar o efeito das variáveis sobre o spread das cotas. Os resultados apontaram que o volume de emissão afeta a forma como outras variáveis afetam o spread. Os fundos com tamanho de oferta maior têm seu spread influenciado por características de seus cedentes e por características de sua estruturação, enquanto que fundos menores são apreçados por negociações entre emissor e investidores.

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Allergic asthma represents an important public health issue, most common in the paediatric population, characterized by airway inflammation that may lead to changes in volatiles secreted via the lungs. Thus, exhaled breath has potential to be a matrix with relevant metabolomic information to characterize this disease. Progress in biochemistry, health sciences and related areas depends on instrumental advances, and a high throughput and sensitive equipment such as comprehensive two-dimensional gas chromatography–time of flight mass spectrometry (GC × GC–ToFMS) was considered. GC × GC–ToFMS application in the analysis of the exhaled breath of 32 children with allergic asthma, from which 10 had also allergic rhinitis, and 27 control children allowed the identification of several hundreds of compounds belonging to different chemical families. Multivariate analysis, using Partial Least Squares-Discriminant Analysis in tandem with Monte Carlo Cross Validation was performed to assess the predictive power and to help the interpretation of recovered compounds possibly linked to oxidative stress, inflammation processes or other cellular processes that may characterize asthma. The results suggest that the model is robust, considering the high classification rate, sensitivity, and specificity. A pattern of six compounds belonging to the alkanes characterized the asthmatic population: nonane, 2,2,4,6,6-pentamethylheptane, decane, 3,6-dimethyldecane, dodecane, and tetradecane. To explore future clinical applications, and considering the future role of molecular-based methodologies, a compound set was established to rapid access of information from exhaled breath, reducing the time of data processing, and thus, becoming more expedite method for the clinical purposes.

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When a company desires to invest in a project, it must obtain resources needed to make the investment. The alternatives are using firm s internal resources or obtain external resources through contracts of debt and issuance of shares. Decisions involving the composition of internal resources, debt and shares in the total resources used to finance the activities of a company related to the choice of its capital structure. Although there are studies in the area of finance on the debt determinants of firms, the issue of capital structure is still controversial. This work sought to identify the predominant factors that determine the capital structure of Brazilian share capital, non-financial firms. This work was used a quantitative approach, with application of the statistical technique of multiple linear regression on data in panel. Estimates were made by the method of ordinary least squares with model of fixed effects. About 116 companies were selected to participate in this research. The period considered is from 2003 to 2007. The variables and hypotheses tested in this study were built based on theories of capital structure and in empirical researches. Results indicate that the variables, such as risk, size, and composition of assets and firms growth influence their indebtedness. The profitability variable was not relevant to the composition of indebtedness of the companies analyzed. However, analyzing only the long-term debt, comes to the conclusion that the relevant variables are the size of firms and, especially, the composition of its assets (tangibility).This sense, the smaller the size of the undertaking or the greater the representation of fixed assets in total assets, the greater its propensity to long-term debt. Furthermore, this research could not identify a predominant theory to explain the capital structure of Brazilian

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In recent decades the public sector comes under pressure in order to improve its performance. The use of Information Technology (IT) has been a tool increasingly used in reaching that goal. Thus, it has become an important issue in public organizations, particularly in institutions of higher education, determine which factors influence the acceptance and use of technology, impacting on the success of its implementation and the desired organizational results. The Technology Acceptance Model - TAM was used as the basis for this study and is based on the constructs perceived usefulness and perceived ease of use. However, when it comes to integrated management systems due to the complexity of its implementation,organizational factors were added to thus seek further explanation of the acceptance of such systems. Thus, added to the model five TAM constructs related to critical success factors in implementing ERP systems, they are: support of top management, communication, training, cooperation, and technological complexity (BUENO and SALMERON, 2008). Based on the foregoing, launches the following research problem: What factors influence the acceptance and use of SIE / module academic at the Federal University of Para, from the users' perception of teachers and technicians? The purpose of this study was to identify the influence of organizational factors, and behavioral antecedents of behavioral intention to use the SIE / module academic UFPA in the perspective of teachers and technical users. This is applied research, exploratory and descriptive, quantitative with the implementation of a survey, and data collection occurred through a structured questionnaire applied to a sample of 229 teachers and 30 technical and administrative staff. Data analysis was carried out through descriptive statistics and structural equation modeling with the technique of partial least squares (PLS). Effected primarily to assess the measurement model, which were verified reliability, convergent and discriminant validity for all indicators and constructs. Then the structural model was analyzed using the bootstrap resampling technique like. In assessing statistical significance, all hypotheses were supported. The coefficient of determination (R ²) was high or average in five of the six endogenous variables, so the model explains 47.3% of the variation in behavioral intention. It is noteworthy that among the antecedents of behavioral intention (BI) analyzed in this study, perceived usefulness is the variable that has a greater effect on behavioral intention, followed by ease of use (PEU) and attitude (AT). Among the organizational aspects (critical success factors) studied technological complexity (TC) and training (ERT) were those with greatest effect on behavioral intention to use, although these effects were lower than those produced by behavioral factors (originating from TAM). It is pointed out further that the support of senior management (TMS) showed, among all variables, the least effect on the intention to use (BI) and was followed by communications (COM) and cooperation (CO), which exert a low effect on behavioral intention (BI). Therefore, as other studies on the TAM constructs were adequate for the present research. Thus, the study contributed towards proving evidence that the Technology Acceptance Model can be applied to predict the acceptance of integrated management systems, even in public. Keywords: Technology

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The study aims to identify the factors that influence the behavior intention to adopt an academic Information System (SIE), in an environment of mandatory use, applied in the procurement process at the Federal University of Pará (UFPA). For this, it was used a model of innovation adoption and technology acceptance (TAM), focused in attitudes and intentions regarding the behavior intention. The research was conducted a quantitative survey, through survey in a sample of 96 administrative staff of the researched institution. For data analysis, it was used structural equation modeling (SEM), using the partial least squares method (Partial Least Square PLS-PM). As to results, the constructs attitude and subjective norms were confirmed as strong predictors of behavioral intention in a pre-adoption stage. Despite the use of SIE is required, the perceived voluntariness also predicts the behavior intention. Regarding attitude, classical variables of TAM, like as ease of use and perceived usefulness, appear as the main influence of attitude towards the system. It is hoped that the results of this study may provide subsidies for more efficient management of the process of implementing systems and information technologies, particularly in public universities

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There are a great number of evidences showing that education is extremely important in many economic and social dimensions. In Brazil, education is a right guaranteed by the Federal Constitution; however, in the Brazilian legislation the right to the three stages of basic education: Kindergarten, Elementary and High School is better promoted and supported than the right to education at College level. According to educational census data (INEP, 2009), 78% of all enrolments in College education are in private schools, while the reverse is found in High School: 84% of all matriculations are in public schools, which shows a contradiction in the admission into the universities. The Brazilian scenario presents that public universities receive mostly students who performed better and were prepared in elementary and high school education in private schools, while private universities attend students who received their basic education in public schools, which are characterized as low quality. These facts have led researchers to raise the possible determinants of student performance on standardized tests, such as the Brazilian Vestibular exam, to guide the development of policies aimed at equal access to College education. Seeking inspiration in North American models of affirmative action policies, some Brazilian public universities have suggested rate policies to enable and facilitate the entry of "minorities" (blacks, pardos1, natives, people of low income and public school students) to free College education. At the Federal University of the state Rio Grande do Norte (UFRN), the first incentives for candidates from public schools emerged in 2006, being improved and widespread during the last 7 years. This study aimed to analyse and discuss the Argument of Inclution (AI) - the affirmative action policy that provides additional scoring for students from public schools. From an extensive database, the Ordinary Least Squares (OLS) technique was used as well as a Quantile Regression considering as control the variables of personal, socioeconomic and educational characteristics of the candidates from the Brazilian Vestibular exam 2010 of the Federal University of the state Rio Grande do Norte (UFRN). The results demonstrate the importance of this incentive system, besides the magnitude of other variables

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Os efeitos de ano e época de nascimento, propriedade, sexo do bezerro, regime alimentar, idade do bezerro e idade da vaca ao parto, os efeitos aditivos direto e materno da raça Charolesa e o efeito de heterose materna entre as raças Charolesa e zebu foram avaliados pelo método dos quadrados míninos sobre características de importância econômica, como peso, perímetro escrotal e escores visuais de conformação frigorífica, de umbigo e de pelame à desmama em bovinos da raça Canchim. Utilizaram-se dados de 12.334 animais Canchim nascidos de 1999 a 2005. O ano e a época de nascimento, a propriedade, o regime alimentar e a idade da vaca ao parto (linear e quadrático) tiveram efeitos significativos sobre todas as características estudadas. Houve efeitos do sexo sobre o peso do bezerro à desmama e o escore de umbigo; da idade do bezerro sobre peso, perímetro escrotal e escores de conformação frigorífica e de pelame; e das proporções de Charolês no bezerro e na mãe sobre o peso, a conformação frigorífica e a qualidade de pelagem; e da heterozigose materna sobre peso, perímetro escrotal e escores de conformação frigorífica e de umbigo. Os efeitos aditivos diretos da raça Charolesa como desvio do zebu foram negativos sobre peso, conformação frigorífica e qualidade da pelagem à demama, enquanto os efeitos aditivos maternos foram positivos. Os efeitos heteróticos maternos foram positivos sobre peso, perímetro escrotal e escores de conformação frigorífica e de umbigo. em geral, essas fontes de variação devem ser consideradas nas estimativas de parâmetros genéticos e nas avaliações genéticas dos animais Canchim para as características estudadas.

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Foram investigados os efeitos das características do pelame e da taxa de sudação (TS) sobre o intervalo de partos (IEP, n = 423) e os dias para o parto (DPP, n = 1.202) de vacas da raça Braford criadas em sistema extensivo em região tropical úmida no Mato Grosso do Sul, Brasil. As análises foram realizadas pelo método dos quadrados mínimos considerando para intervalo de partos os seguintes efeitos das classes de idade da vaca ao parto: grupo genético; pai; e regressão sobre a refletância da superfície da capa (R), a espessura da capa (E), o comprimento dos pêlos (C), o número de pêlos por unidade de área (N), o diâmetro dos pêlos (D) e a taxa de sudação. Para dias para o parto, foram considerados os efeitos: R, E, C, N, D, TS, divididos em classes; grupo genético; idade no início da estação de monta; e pai. Os componentes de variância e co-variância foram estimados pelo método de Máxima Verossimilhança Restrita sob o modelo touro. As características adaptativas não foram importantes para a variação do intervalo de parto e dos dias para o parto, mas a taxa de sudação apresentou efeito importante sobre dias ao parto. As estimativas de herdabilidade foram quase nulas para IEP e DPP e maiores para as características adaptativas (E = 0,16 ± 0,09; C = 0,18 ± 0,09; N = 0,08 ± 0,06; D = 0,12 ± 0,07; R = 0,30 ± 0,12; TS = 0,10 ± 0,06). Os resultados obtidos para as correlações genéticas de IEP e DPP com TS e entre as características do pelame indicaram que a seleção simultânea para menores valores de C pode ser favorável à redução do intervalo de partos. em geral, as correlações genéticas entre TS, IEP e DPP apresentaram elevado erro-padrão. Considerando os resultados deste estudo e a importância das características do pelame e da sudação, confirma-se a necessidade de se estudarem as correlações genéticas entre as características adaptativas e o desempenho reprodutivo para o progresso da adaptação de bovinos da raça Braford no Brasil.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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This paper presents a new multi-model technique of dentification in ANFIS for nonlinear systems. In this technique, the structure used is of the fuzzy Takagi-Sugeno of which the consequences are local linear models that represent the system of different points of operation and the precursors are membership functions whose adjustments are realized by the learning phase of the neuro-fuzzy ANFIS technique. The models that represent the system at different points of the operation can be found with linearization techniques like, for example, the Least Squares method that is robust against sounds and of simple application. The fuzzy system is responsible for informing the proportion of each model that should be utilized, using the membership functions. The membership functions can be adjusted by ANFIS with the use of neural network algorithms, like the back propagation error type, in such a way that the models found for each area are correctly interpolated and define an action of each model for possible entries into the system. In multi-models, the definition of action of models is known as metrics and, since this paper is based on ANFIS, it shall be denominated in ANFIS metrics. This way, ANFIS metrics is utilized to interpolate various models, composing a system to be identified. Differing from the traditional ANFIS, the created technique necessarily represents the system in various well defined regions by unaltered models whose pondered activation as per the membership functions. The selection of regions for the application of the Least Squares method is realized manually from the graphic analysis of the system behavior or from the physical characteristics of the plant. This selection serves as a base to initiate the linear model defining technique and generating the initial configuration of the membership functions. The experiments are conducted in a teaching tank, with multiple sections, designed and created to show the characteristics of the technique. The results from this tank illustrate the performance reached by the technique in task of identifying, utilizing configurations of ANFIS, comparing the developed technique with various models of simple metrics and comparing with the NNARX technique, also adapted to identification