Made available in DSpace on 2014-06-12T17:17:24Z (GMT). No. of bitstreams: 2 arquivo6079_1.pdf: 1109326 bytes, checksum: 06554ffc43cc34d3905460ae38378f7a (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2006 / A partir dos microdados dos Censos Demográficos de 1980, 1991 e 2000, o trabalho descreve os padrões de migração em várias dimensões: inter-regional, interestadual, rural-urbano e urbanourbano. Em termos da migração interestadual, Minas Gerais é o estado com maior participação relativa na emissão de migrantes, embora, a participação diminua ao longo do período analisado. Em uma outra dimensão da migração a migração inter-regional, os resultados apontam para um aumento no estoque líquido negativo de migrantes do Nordeste para as demais regiões brasileiras, passando de pouco mais de 4 milhões em 1980 para mais de 8 milhões em 2000. Neste mesmo período, a região Sul passa de um saldo líquido positivo de mais de 200 mil migrantes para um saldo líquido negativo de mais de hum milhão e duzentos mil migrantes. No que se refere à migração rural-urbana, destaca-se o Nordeste, como fonte emissora principal deste tipo de migração, embora haja uma tendência de diminuição deste fluxo ao longo do tempo, não somente oriundo do Nordeste, mas de todas as regiões brasileiras. Buscou-se, também, fornecer evidências a respeito dos determinantes dos fluxos migratórios procurando explorar duas dimensões pouco enfatizadas por estudos sobre fluxos migratórios no Brasil: a importância da incerteza quanto à renda na decisão de migrar e a importância de características do mercado de trabalho. Nesse sentido, buscou-se, sempre com base nos microdados dos Censos, ressaltar a importância da variável renda esperada (renda ponderada pela possibilidade de conseguir emprego), o efeito da distância e população (através da matriz de transformação espacial). Os resultados obtidos a partir de dados em painel e de uma transformação espacial das variáveis indicam que o controle espacial é fundamental para apreender o efeito das variáveis sobre o fluxo migratório. Ainda tendo como base os microdados censitários, o trabalho fornece evidências a respeito do perfil do migrante interno brasileiro de acordo com a região de destino. Através da estimação de um modelo logit multinomial para a decisão de migração e de escolha do destino, os resultados permitiram apontar as diferenças entre migrantes e não-migrantes e entre os próprios migrantes de acordo com a região de destino para todos os anos censitários. Entre as evidências obtidas mostra-se que qualquer que seja a região de destino e o período de migração entre 1980 e 2000, o migrante brasileiro apresenta perfil distinto daquele do não-migrante: é mais escolarizado, mais jovem sobretudo do sexo masculino e provém com maior probabilidade de UF em condição social relativamente precária. Enquanto no período 1980 -1991, há elevação das diferenças entre migrantes de acordo com a região de destino, entre 1991 e 2000, os migrantes tornam-se regionalmente mais semelhantes. Por fim, novamente utilizando-se os microdados censitários, o trabalho procurou testar se os migrantes brasileiros formam um grupo positivamente selecionado (ou seja, em média mais apto, empreendedor, motivado e ambicioso que o grupo dos nãomigrantes). Os resultados permitem apontar que há, em média, uma diferença de renda favorável aos migrantes em relação aos não-migrantes que moram nos estados que os recebem, assim como em relação aos não-migrantes dos seus estados de origem, mesmo quando controlados por uma série de variáveis importantes na determinação da renda. Desta forma, os resultados sugerem que os migrantes brasileiros constituem um grupo positivamente selecionado

Made available in DSpace on 2014-06-12T17:21:57Z (GMT). No. of bitstreams: 2 arquivo6466_1.pdf: 414575 bytes, checksum: b3762dbf01db298f4b18db77da682cd6 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2002 / O presente trabalho tem como objetivo a avaliação do Jardim Botânico da cidade de João Pessoa, cuja efetivação visa a preservação de uma das maiores riquezas naturais dessa Cidade: a Mata do Buraquinho. A avaliação do Jardim Botânico é feita a partir do método de avaliação contingente. São apresentados ainda aspectos fundamentais do mesmo, tais como: as bases microeconômicas, sua definição, suas vantagens e desvantagens etc. São apresentadas também considerações a respeito de outros instrumentos de valoração ambiental, de modo a permitir uma comparação que justifique a escolha do método de avaliação contingente. A necessidade da aplicação de métodos de valoração ambiental deve-se ao fato de que os ativos ambientais, por possuírem característica de bens públicos, não são transacionados no mercado. A base de mensuração utilizada aqui foi a máxima disposição a pagar (DAP), captada a partir do método referendo. A estimação dos valores foi feita a partir da aplicação do modelo logit em dados primários, obtidos a partir da aplicação de questionários

nÃo hà / The main objective of this thesis was to investigate the factors determining success in an aptitude test for admission in a public bank in the Northeast of Brazil. The data set is based in a questionnaire for 232,771 Candidates which is composed of the result of the test and a number of questions about some attributes of the candidate. Attributes selected were personal monthly income; household monthly income; education level; type of school attended (public or private); marital status; occupation and age. A logit model was used to estimate a regression of success in the test against the attributes defined above. Results of the estimated model show that all the coefficients but marital status were significant and with the expected sign. The marginal effects inform that a high school level (a requirement to take the test) had the strongest and negative impact on the probability of success. Specification tests for functional form and unobserved heterogeneity show that the model was correctly specified. / O concurso pÃblico para provimento de cargos do aparelho do Estado brasileiro à um forte atrator de recursos humanos, e no qual se observa uma grande demanda de pessoas buscando uma carreira atravÃs da aprovaÃÃo num conjunto de provas. A principal preocupaÃÃo deste trabalho foi a de investigar os determinantes da aprovaÃÃo de um candidato num concurso pÃblico. Para tanto fez-se um estudo de caso com base em dados e resultados de um concurso para provimento de cargo administrativo de nÃvel mÃdio para o Banco do Nordeste do Brasil, do qual participaram 232.771 candidatos. Discute-se ainda o problema paralelo da super-educaÃÃo como forma de ilustrar uma possÃvel mà alocaÃÃo de recursos no mercado de trabalho. Na base de dados utilizada, alÃm do resultado do concurso, constam informaÃÃes referentes à renda, educaÃÃo e outros atributos mais gerais como faixa de idade, estado civil e local de origem do candidato. Na regressÃo o resultado do candidato no concurso (aprovado ou reprovado) à a variÃvel a ser explicada, e o vetor de variÃveis explicativas à formado pelos atributos dos candidatos. Utiliza-se inicialmente o modelo logit de escolha binÃria e a estimaÃÃo à baseada no mÃtodo de mÃxima verossimilhanÃa. Resultados padrÃes foram obtidos nos testes de razÃo de mÃxima verossimilhanÃa e de significÃncia estatÃstica de cada um dos parÃmetros estimados, onde somente uma variÃvel, referente ao estado civil, nÃo se mostrou estatisticamente significativa. As que se mostraram significativas apresentaram os sinais esperados quanto ao efeito marginal sobre a chance de aprovaÃÃo. Quanto à magnitude dos coeficientes, o dado relevante à que a condiÃÃo do candidato ter o grau de escolaridade requerido para a funÃÃo a ser exercida (nÃvel mÃdio) foi o que apresentou maior impacto (negativo) na chance do candidato ser aprovado. Para avaliar problemas de especificaÃÃo do modelo dois tipos de teste foram realizados. O primeiro foi um teste de heterocedasticidade, cujo objetivo foi detectar erro de especificaÃÃo para o caso de heterogeneidade nÃo observada. Detectou-se ausÃncia de erro de especificaÃÃo. O segundo teste foi quanto a forma funcional, onde confrontou-se os modelos logit e probit e, em seguida, cotejou-se o melhor dentre esses modelos simÃtricos versus um com distribuiÃÃo gompit, como representativa da classe assimÃtrica. Como resultado obteve-se uma razoÃvel confianÃa de que o modelo logit à bem especificado. As principais conclusÃes do trabalho apontam o ensino mÃdio pÃblico como um possÃvel locus de aÃÃo e polÃticas que atuem para reduzir as desigualdades de condiÃÃes iniciais de cada candidato a concursos pÃblicos. Por outro lado, o preenchimento de postos de trabalho que requerem apenas uma educaÃÃo de nÃvel mÃdio com detentores de tÃtulo universitÃrio, e atà mesmo com pÃs-graduaÃÃo, aponta para uma mà alocaÃÃo dos recursos pÃblicos conjugada com uma possÃvel deficiÃncia estrutural do mercado de trabalho regional.

This thesis is based on three essays in corporate credit risk and economic performance analysis. Corporate bankruptcy prediction using past financial information is well established in the literature. Early studies of corporate bankruptcy prediction mainly applied statistical techniques such as discriminant analysis, logit and probit. Although, some of these models such as logit is still widely popular amongst the academics and practitioners due to its simplicity, the shortcomings of such models for bankruptcy prediction have been noticed and criticised in the literature. One of the main shortcomings is that these models as linear classification approach can not explain the possible non-linear relationship between some accounting ratios and the probability of default (PD). This issue has been addressed in the literature by introducing non-linear statistical techniques such as support vector machines (SVM). The first essay of this thesis, presented in Chapter 2, investigates the performance of SVM in corporate bankruptcy prediction and compares its performance with that of logit. This essay analyses bankruptcy risk for firms in the Asian and Pacific region using a list of financial ratios which covers different aspects of a firm's performance. The financial and credit event information for this analysis is provided by the Risk Management Institute of National University of Singapore (RMI NUS). With respect to forecasting accuracy, the findings of this analysis reveal that on average the SVM displays a higher forecasting accuracy and a more robust performance than the logit. Among several financial ratios suggested as predictors of default, leverage ratios and firm size display a higher discriminating power compared to others. Additionally, an analysis of the relationship between PD and financial ratios is provided. The accounting based models in bankruptcy analysis are mostly based on a set of measures which represents current financial position of the firms. However, these models have no indication of the status of the technology competency of a firm amongst its peers, which could be a more significant factor in the survival of a firm. Therefore, a new measure about level of firm's technological knowledge is required for a more precise assessment of firms future financial performance. Considering the rise in the technological competition and patenting activities since the 1990s and also the important role of accurate credit rating modeling in the financial stability, second essay of this thesis examined in Chapter 3 focuses on the relationship between patent applications, as an output of a firm's technological development, and financial survival. Applying a survival analysis model, this relationship is empirically tested on a longitudinal firm-level data set for the listed firms in the US which matches the patent application data from European Patent Offi ce (EPO) against a set of financial variables provided by RMI NUS. The results of this analysis reveal that patent applications are strong identifiers of low default risk companies. In a further analysis, third essay of this thesis presented in Chapter 4 focuses on the impact of patent applications on firm's economic performance. In contrast to the studies which study the overall patent portfolio indicators as proxy for innovation, on a few aspects of firm performance this essay provides a comprehensive analysis of the effect of individual patent applications on several aspects of firm performance including including profitability, leverage, liquidity, size, credit rating quality and stock return. Using the matched data set of patent application data and economic variables for the US listed firms explained earlier, this essay examines whether changing from non-patenting to patenting status when a firm files its first and subsequent applications is associated with significant changes in its firm's performance and stability. The empirical findings of this essay indicates a higher capitalisation, increased liquidity, a lower leverage and an improve in credit quality for the patenting firms.

<p> The logit format for a modal split model, which has previously been used for only binary cases, is used to build a new set of behavioural, probabilistic, multi-mode models. The models and the testing were carried out on a CDC 6400 Computer. </p> <p> A program developed at Chicago was used to construct the models while a separate program was developed to analyze the results. The type and number of variables to be used in the different sections of the model were investigated and an attempt was made to find the best method of aggregation. An inferred 'value of time' was also calculated and statistical testing of the individual and aggregate models was made. </p> <p> It is shown that this method of modelling is indeed feasible in terms of the significance of the models and the accuracy of the predictions on a separate data set. </p> / Thesis / Master of Engineering (ME)

No description available.

This dissertation explores the persistent gap between rural and urban areas in the percentage of households that access the Internet at home (a discrepancy commonly known as the "digital divide"). The theoretical framework underlying a household's Internet adoption decision is examined, with emphasis on the roles that household characteristics, network externalities, and digital communication technology (DCT) infrastructure potentially play. This framework is transferred into a statistical model of household Internet access, where non-linear decomposition techniques are employed to estimate the contributions of these variables to the digital divide in a given year. Differences in Internet access rates between years are also analyzed to understand the importance of temporal resistance to the continuing digital divide. The increasing prevalence of "high-speed" or broadband access is also taken into account by modeling a decision process where households that choose to have Internet access must decide between dial-up and high-speed access. This nested process is also decomposed in order to estimate the contributions of household characteristics, network externalities, DCT infrastructure, and temporal resistance to the high-speed digital divide. The results suggest that public policies designed to alleviate digital divides in both general and high-speed access should focus more on the broader income and education inequities between rural and urban areas. The results also imply that the current policy environment of encouraging DCT infrastructure investment in rural areas may not be the most effective way to close the digital divide in both general and high-speed Internet access. / Ph. D.

On-Demand Mobility (ODM) is a concept to address congestion problems. Using electric aircraft and vertical take-off with limited landing (VTOL) capabilities, the ODM concept offers on demand transportation service between designated landing sites at a fraction of driving time. The purpose of this research is to estimate the potential ODM demand and understand the challenges of introducing ODM using the Northern California region (including major cities like San Francisco, Sacramento, and San Jose) as an area of study and a second, less rigorous analysis for the Washington-Baltimore region. A conditional logit model was developed to estimate mode choice behavior and to estimate ODM demand; presenting automobile and public transportation as the two competing modes to ODM. There are significant challenges associated with the service including ability to operate in bad weather, vehicle operating cost, siting and cost of landing sites, and overall public acceptance of small, remotely operated aircraft. Nine scenarios were run varying the input for a base fare, landing fare, cost per-passenger-mile, auto operational costs, and ingress (waiting) times. The results yielded sensitivity of demand to all these parameters and especially showed a great difference in demand when auto costs were decreased from the standard American Automobile Association (AAA) cost per mile to a likely, future auto operating cost. The challenge that aerospace engineers face is designing an aircraft capable of achieving lower operational costs. The results showed that in order for the ODM to be a competitive mode, the cost per passenger-mile should be kept at $1. / Master of Science / On-Demand Mobility (ODM) is a concept to address congestion problems. Using an electric propulsion aircraft, the ODM concept offers on demand transportation service between designated landing sites at a fraction of driving time; an “air taxi” or “air Uber” as coined by media outlets. The purpose of this research is to estimate the potential ODM demand and understand the challenges of introducing ODM using the Northern California region (including major cities like San Francisco, Sacramento, and San Jose) as an area of study and a second, less rigorous analysis for the Washington-Baltimore region. A model was developed to estimate mode choice behavior and to estimate ODM demand based on existing travel behavior and patterns in the Northern California region. There are significant challenges associated with the service including ability to operate in bad weather, vehicle operating cost, siting and cost of landing sites, and overall public acceptance of small, remotely operated aircraft. The results from the model yielded sensitivity of demand to these challenges and especially showed a great difference in demand as the cost of operating the car decreases in the future, making it a great competitor to the ODM concept. The major challenge that aerospace engineers face is designing an aircraft capable of achieving lower operational costs. The results showed that in order for the ODM to be a competitive mode, the cost per passenger-mile should be kept at $1.

Improper pesticide use on crops causes adverse effects on humans, livestock, crops and the environment. Integrated pest management practices emphasize minimal use of pesticides in controlling pests, and their adoption by farmers can reduce the use of pesticides and their adverse impacts. The introduction of IPM CRSP activities in Uganda to institutionalize IPM methods focused on priority crops in the country. This study analyzed adoption of eight IPM technologies on cowpea, sorghum and groundnuts. Low levels of adoption (<25%) were found with five of these technologies while three technologies had high adoption levels (>75%). Results indicate that farmers' participation in on-farm trial demonstrations, accessing agricultural knowledge through researchers, and prior participation in pest training were associated with increased adoption of most IPM practices. Size of farmer's land holdings did not affect IPM adoption suggesting that IPM technologies are mostly scale neutral, implying that IPM dissemination may take place regardless of farmer's scale of operation. Farmers' perception of harmful effects of chemicals did not influence farmers' decisions in regard to IPM technology adoption despite their high knowledge of this issue, suggesting that these farmers did not consider environmental and health impacts important factors when choosing farming practices. Farmers' managerial capabilities were not important in explaining cowpea IPM technology adoption. / Master of Science

Este trabalho procurou avaliar as correlações existentes entre as características dos docentes, da escola, dos diretores, além da percepção dos professores e do diretor, e da conjuntura econômica sobre a decisão do professor de abandonar a rede pública estadual paulista. Os resultados indicam que as características dos docentes exercem uma forte influência sobre a decisão destes de evadir. Em relação às características da escola, tanto para o PEB I quanto para o PEB II o número de matrículas foi estatisticamente significantes para explicar a evasão, assim como, a experiência do diretor. Apenas para o PEB II o resultado da escola no Saresp foi relevante, a característica familiar dos alunos diferiu no seu comportamento entre os modelos. As variáveis de percepção também apresentaram significância em alguns dos quesitos analisados. Desta forma, conclui-se, neste estudo, que diferentes aspectos intervêm na decisão do docente de permanecer na rede e, ainda que com alguns resultados contraditórios, o ambiente de trabalho parece ser um fator relevante nesta decisão / This study aimed to evaluate the correlation between the characteristics of teachers, school, directors, the perception of teachers and the director, and the economic environment on the decision of the teacher to abandon the São Paulo State public schools. The results indicate that the characteristics of teachers has a strong influence on the dropout decision. In relation to the characteristics of the school, its enrollment number and principal experience were statistically significant to explain the teacher\'s dropout. Only for those teachers who attends students from 5th grade or more, the performance of students in the SARESP test was important. In addition the family background was also important, but with different results according to types of teachers. In some dimensions, the perception of the Director and of the teachers also was significant. So we conclude that different variables influence the dropout decision of teachers. The characteristics of the teachers itself, as well as characteristics of the school can explain why teachers get out their Jobs in the São Paulo state schools