Atualmente, os computadores pessoais são equipados com processadores de vários núcleos possuem alto poder de processamento. Algumas pesquisas realizadas indicam que estes mesmos computadores permanecem em média 80% do tempo ociosos. A união destas duas informações fomenta à pesquisa de um tipo de computação distribuída, conhecida como grades oportunistas. A utilização de um ambiente de grade oportunista permite a implementação de um computador paralelo capaz de processar grandes volumes de tarefas, com baixo custo financeiro. Apesar do baixo custo financeiro proporcionado por este ambiente, tem-se um alto custo computacional devido a utilização de recursos não dedicados. Estes ambientes sofrem de um problema que tem servido de objeto de diversas pesquisas, a indisponibilidade de recursos. O problema da indisponibilidade de recursos deve-se a volatilidade deste recursos. A volatilidade deve-se a liberdade de tornarem-se ociosos ou ocupados a qualquer instante, sem a necessidade de aviso prévio ao servidor. A volatilidade é a responsável por gerar uma série de interrupções de execução de tarefas e a consequente necessidade de novos escalonamentos desta mesma tarefa. Para reduzir o impacto deste problema, o escalonador de tarefas poderia considerar informações sobre o comportamento futuro dos recursos, ou seja, poderia considerar informações provenientes de um preditor de disponibilidade. Este trabalho propõe o modelo AvSchedP, modelo este capaz de realizar a previsão de disponibilidade baseando-se em dados binários e de forma dinâmica. O modelo AvSchedP foi projetado para ser integrado a escalonadores de grades oportunistas. O AvSchedP foi implementado e diversos experimentos foram realizados. Os experimentos foram realizados para avaliar a qualidade de previsão e a adequação do modelo a um sistema de grade oportunista, o XtremWeb. Os resultados obtidos demonstram que o AvSchedP apresenta bons resultados ao realizar previsões de duração de disponibilidade em ambientes formados por recursos voláteis. / Nowadays, personal computers have multi-core processors with high processing power. Some researches show that these computers remain 80 % of the time idle. The union of these two information instigates a kind of distributed computing, known as opportunistic grids. The opportunistic grid environment usage allows the implementation of a parallel computer like, capable of processing large volumes of tasks, with a low cost. Despite the low financial cost, it has a high computational cost due to use of nondedicated resources. Opportunistic grid environments have a problem that has been the subject of several researches: the resource availability. The resource availability problem is caused by the volatility of resources. The resource is free to become idle or busy at any time without notice the server. The volatility is responsible for generating a lot of task execution interruptions and consequently, task rescheduling. To alleviate this problem, the task scheduler could consider information about the future behavior of resources provided by an avalibility predictor. This paper proposes a new model, called AvSchedP , to perform dynamic resource availability prediction based on binary data. The model was designed to be integrated into opportunistic grid schedulers. The AvSchedP was implemented and several experiments were performed. These experiments were conducted to evaluate the prediction quality and the model integrability to the XtremWeb opportunistic grid system. The results show that the AvSchedP has good results when making availability duration predictions for environments composed by volatile resources.

Atualmente, os computadores pessoais são equipados com processadores de vários núcleos possuem alto poder de processamento. Algumas pesquisas realizadas indicam que estes mesmos computadores permanecem em média 80% do tempo ociosos. A união destas duas informações fomenta à pesquisa de um tipo de computação distribuída, conhecida como grades oportunistas. A utilização de um ambiente de grade oportunista permite a implementação de um computador paralelo capaz de processar grandes volumes de tarefas, com baixo custo financeiro. Apesar do baixo custo financeiro proporcionado por este ambiente, tem-se um alto custo computacional devido a utilização de recursos não dedicados. Estes ambientes sofrem de um problema que tem servido de objeto de diversas pesquisas, a indisponibilidade de recursos. O problema da indisponibilidade de recursos deve-se a volatilidade deste recursos. A volatilidade deve-se a liberdade de tornarem-se ociosos ou ocupados a qualquer instante, sem a necessidade de aviso prévio ao servidor. A volatilidade é a responsável por gerar uma série de interrupções de execução de tarefas e a consequente necessidade de novos escalonamentos desta mesma tarefa. Para reduzir o impacto deste problema, o escalonador de tarefas poderia considerar informações sobre o comportamento futuro dos recursos, ou seja, poderia considerar informações provenientes de um preditor de disponibilidade. Este trabalho propõe o modelo AvSchedP, modelo este capaz de realizar a previsão de disponibilidade baseando-se em dados binários e de forma dinâmica. O modelo AvSchedP foi projetado para ser integrado a escalonadores de grades oportunistas. O AvSchedP foi implementado e diversos experimentos foram realizados. Os experimentos foram realizados para avaliar a qualidade de previsão e a adequação do modelo a um sistema de grade oportunista, o XtremWeb. Os resultados obtidos demonstram que o AvSchedP apresenta bons resultados ao realizar previsões de duração de disponibilidade em ambientes formados por recursos voláteis. / Nowadays, personal computers have multi-core processors with high processing power. Some researches show that these computers remain 80 % of the time idle. The union of these two information instigates a kind of distributed computing, known as opportunistic grids. The opportunistic grid environment usage allows the implementation of a parallel computer like, capable of processing large volumes of tasks, with a low cost. Despite the low financial cost, it has a high computational cost due to use of nondedicated resources. Opportunistic grid environments have a problem that has been the subject of several researches: the resource availability. The resource availability problem is caused by the volatility of resources. The resource is free to become idle or busy at any time without notice the server. The volatility is responsible for generating a lot of task execution interruptions and consequently, task rescheduling. To alleviate this problem, the task scheduler could consider information about the future behavior of resources provided by an avalibility predictor. This paper proposes a new model, called AvSchedP , to perform dynamic resource availability prediction based on binary data. The model was designed to be integrated into opportunistic grid schedulers. The AvSchedP was implemented and several experiments were performed. These experiments were conducted to evaluate the prediction quality and the model integrability to the XtremWeb opportunistic grid system. The results show that the AvSchedP has good results when making availability duration predictions for environments composed by volatile resources.

Atualmente, os computadores pessoais são equipados com processadores de vários núcleos possuem alto poder de processamento. Algumas pesquisas realizadas indicam que estes mesmos computadores permanecem em média 80% do tempo ociosos. A união destas duas informações fomenta à pesquisa de um tipo de computação distribuída, conhecida como grades oportunistas. A utilização de um ambiente de grade oportunista permite a implementação de um computador paralelo capaz de processar grandes volumes de tarefas, com baixo custo financeiro. Apesar do baixo custo financeiro proporcionado por este ambiente, tem-se um alto custo computacional devido a utilização de recursos não dedicados. Estes ambientes sofrem de um problema que tem servido de objeto de diversas pesquisas, a indisponibilidade de recursos. O problema da indisponibilidade de recursos deve-se a volatilidade deste recursos. A volatilidade deve-se a liberdade de tornarem-se ociosos ou ocupados a qualquer instante, sem a necessidade de aviso prévio ao servidor. A volatilidade é a responsável por gerar uma série de interrupções de execução de tarefas e a consequente necessidade de novos escalonamentos desta mesma tarefa. Para reduzir o impacto deste problema, o escalonador de tarefas poderia considerar informações sobre o comportamento futuro dos recursos, ou seja, poderia considerar informações provenientes de um preditor de disponibilidade. Este trabalho propõe o modelo AvSchedP, modelo este capaz de realizar a previsão de disponibilidade baseando-se em dados binários e de forma dinâmica. O modelo AvSchedP foi projetado para ser integrado a escalonadores de grades oportunistas. O AvSchedP foi implementado e diversos experimentos foram realizados. Os experimentos foram realizados para avaliar a qualidade de previsão e a adequação do modelo a um sistema de grade oportunista, o XtremWeb. Os resultados obtidos demonstram que o AvSchedP apresenta bons resultados ao realizar previsões de duração de disponibilidade em ambientes formados por recursos voláteis. / Nowadays, personal computers have multi-core processors with high processing power. Some researches show that these computers remain 80 % of the time idle. The union of these two information instigates a kind of distributed computing, known as opportunistic grids. The opportunistic grid environment usage allows the implementation of a parallel computer like, capable of processing large volumes of tasks, with a low cost. Despite the low financial cost, it has a high computational cost due to use of nondedicated resources. Opportunistic grid environments have a problem that has been the subject of several researches: the resource availability. The resource availability problem is caused by the volatility of resources. The resource is free to become idle or busy at any time without notice the server. The volatility is responsible for generating a lot of task execution interruptions and consequently, task rescheduling. To alleviate this problem, the task scheduler could consider information about the future behavior of resources provided by an avalibility predictor. This paper proposes a new model, called AvSchedP , to perform dynamic resource availability prediction based on binary data. The model was designed to be integrated into opportunistic grid schedulers. The AvSchedP was implemented and several experiments were performed. These experiments were conducted to evaluate the prediction quality and the model integrability to the XtremWeb opportunistic grid system. The results show that the AvSchedP has good results when making availability duration predictions for environments composed by volatile resources.

A major challenge in ecology is to understand intraspecific variation in life histories. Variation in resource availability can lead to differences in reproductive allocation and life histories. Grasshoppers are a good organism for the study of variation in life histories, since they exhibit life history plasticity in response to biotic and environmental factors. An optimality model for grasshoppers was developed that predicts optimal total allocation to reproduction and optimal effort-per-offspring as functions of resource availability and mortality. Relative allocation to reproduction is predicted to increase with resource availability, while relative allocation to survival declines. A resource-based trade-off between egg size and number does not exist, as optimal egg size is predicted to be independent of resource intake. I examined if changes in reproductive allocation and survival of Melanoplus sanguinipes (Fabricus) under a range of resource availabilities fit the predictions of the model. The patterns of reproductive allocation and survival in the field were in qualitative agreement with the predictions. I examined the importance of density, resources, and parasitism on the life history patterns of grasshoppers. I conducted an experiment to examine if differences in reproductive allocation of M. sanguinipes are primarily explained by exploitative competition. Per capita resource availability explained a significant amount of the variation in reproduction , as expected with exploitative competition. M. sanguinpes grasshoppers appeared to trade off resource allocation to reproduction for that of allocation to survival, because per capita resource availability did not affect survival. Careful examinations of changes in life history characteristics in response to parasitism are lacking, despite the fact that parasites often influence resource availability for the host. I investigated the effects of a grasshopper ectoparasitic mite on grasshopper reproduction and survival. Mites had small effects on grasshopper survival. As predicted, both species had reduced initial and total reproduction, and completed development of a lower percentage of ovarioles initiated when parasitized. These experiments act to expand our knowledge of life history theory and further our understanding of grasshopper life history variation and population fluctuations.

Agricultural literacy has been a topic of concern as most of the population have little to no understanding of agriculture, and the impact it has on society. Agricultural literacy can be defined as “having knowledge and understanding of agriculturally related scientific and technologically based concepts and processes required for personal decision making” (Meischen & Trexler, 2003, p.44). Numerous studies have been conducted to determine the significance of agricultural literacy beginning with elementary aged children and continuing through high school. The majority of studies conducted focus on public school students and teachers. This has led to a gap in the knowledge of students’ agricultural literacy in private schools. There are few studies that indicate if agriculture is being taught in private schools, subsequently there is little known about private school teachers’ willingness to incorporate agriculture into their classrooms. To improve agricultural literacy, it is necessary to place an emphasis on agricultural education.

Master of Science / Division of Biology / John M. Blair / Temperate grasslands are among the most threatened biomes in the world, with the largest historical losses due to conversion to agricultural land. While much of this biome has already been converted, there is concern the last remaining remnants in North America will be converted in response to increasing demand for crops used for ethanol production. Thus, restoring grasslands post-anthropogenic disturbance is increasingly important for conserving grassland biodiversity. Two major challenges for prairie restorations are establishing the many subdominant and rarer species found in native prairie, and offsetting the typical decline in richness and diversity over time as restorations age. Repeated seed addition of targeted species is commonly used to override low and declining plant richness and diversity. While this is generally effective early in restoration (i.e., as communities are establishing), its effectiveness in later stages (i.e., when established communities are often losing diversity) remains unknown. I investigated plant community responses to combinations of resource manipulations and disturbances coupled with a seed addition in a 15-yr old restored grassland to test the hypothesis that spatial resource heterogeneity increases the rate of colonization into established prairie restoration communities. Seeds were added to a long-term restoration experiment involving soil depth manipulations (deep, shallow) crossed with nutrient manipulations (reduced N, ambient N, enriched N). Seedling emergence was generally low and only 8 of the 14 forb species added were detected in the first growing season. I found no effect of increased resource heterogeneity on the abundance or richness of seedlings. There was a significant nutrient effect (p<0.1, α=0.1) on seedling abundance, with higher emergence in the enriched N than the ambient N treatment. I also found unexpected nutrient effects on richness, diversity and Mean C (Mean C = Σ CoCi*Ai, where CoC=Coefficient of Conservatism and A=relative abundance of the ith species). All values, except Mean C, were higher in the enriched N treatment than in either the reduced or ambient N treatments. Mean C was lowest in the enriched N treatment, and highest in the whole-plot control, suggesting that the majority of species contributing to higher richness and diversity in the enriched N treatment were “weedier” species. In a separate experiment, I found no effect of small-scale disturbances (aboveground biomass removal or soil disturbance) on seedling abundance or seedling richness. I did find a marginal effect of disturbance type on seedling richness (p=0.11, α=0.1), with higher seedling richness in the soil disturbance than the aboveground biomass removal treatment. I did not find any disturbance effects on community response variables. These results indicate that recruitment from seed additions into well-established restored communities is relatively low in the first year following a seed addition, regardless of resource availability and heterogeneity. Follow-up studies to determine recruitment rates in subsequent years are needed to elucidate whether recruitment responses are driven more by individual species differences or by environmental mechanisms.

Este trabalho propõe uma heurística construtiva determinística e uma heurística construtiva probabilística para resolver o problema de programação de projetos com custo de disponibilidade de recursos e custo de penalidade por atraso no término do projeto (RACPT - Resource Availability Cost Problem with Tardiness). Os algoritmos combinam a flexibilidade da atividade com a flexibilidade do recurso para selecionar a próxima atividade a ser programada. A data de início de uma atividade é a data mais cedo em que sua execução não gera o maior pico de utilização dos recursos ou a data mais cedo na qual o custo total do projeto for menor. A melhor versão das heurísticas foi obtida após o teste de várias regras de prioridade, conforme a revisão bibliográfica realizada. As heurísticas propostas foram testadas em 360 instâncias de testes e seus resultados foram comparados aos obtidos pela formulação matemática baseada em strip packing e restrições disjuntivas implementada no programa CPLEX. A heurística construtiva determinística gera uma solução viável rapidamente, porém de baixa qualidade. Já a heurística construtiva probabilística gera soluções ótimas ou próximas da ótima para problemas pequenos ou para problemas fáceis e gera soluções muito melhores do que o CPLEX na metade do tempo computacional para os problemas médios e grandes ou para problemas difíceis. Dado os bons resultados obtidos e à implementação no programa VBA for Microsoft Excel, a heurística construtiva probabilística proposta é um método bom e prático para resolução do RACPT. / This work proposes a deterministic constructive heuristic and a probabilistic constructive heuristic for solving the resource availability cost problem with tardiness (RACPT). The algorithms combine the flexibility of an activity with the flexibility of a resource to select the next activity to be scheduled. The start time of the activity is the earliest date in which the activity\'s execution does not create resources usage peak or the earliest date with the lowest total project cost. We tested several priority rules according to the literature review and determined the best version of the heuristics. Afterwards, we tested the proposed heuristics in 360 instances and compared its results with the solutions obtained by the optimization software CPLEX. The RACPT implementation on CPLEX utilized a mathematical formulation based on strip packing concepts and disjunctive constraints. The computational results showed that the deterministic constructive heuristic generates feasible solutions of poor quality in low computational time. The probabilistic constructive heuristic achieved better results. For small instances or easy problems, it found optimal or near-optimal solutions. For medium and large instances or hard problems, it obtained better results than CPLEX in half-computational time. We believe that the probabilistic constructive heuristic is a good and practical method for solving the RACPT. The proposed algorithm produced good results in reasonable computational time and was implemented on the popular software VBA for Microsoft Excel.

nÃo hà / Este estudo investiga o impacto dos instrumentos de polÃtica monetÃria e fiscal sobreas os recursos arrecadados pelo Governo Federal e disponÃveis aos demais entes federados do Brasil. As variÃveis dependentes estudadas foram o Imposto de Renda (IR), o Imposto sobre Produtos Industrializados (IPI) e algumas componentes daquele, tais como o Imposto de Renda Retido na Fonte e o Imposto de Renda Pessoa JurÃdica de empresas nÃo financeiras, enquanto os controles foram a taxa SELIC, os meios de pagamento restritos (M1) e a taxa de cÃmbio (real/dÃlar). Modelos economÃtricos tradicionais de sÃries temporais foram estimados com dados mensais entre janeiro de 2008 a dezembro de 2012 e os resultados obtidos permitiram inferir com elevada robustez que: i) variaÃÃes positivas no dÃlar proporcionam diminuiÃÃes nas arrecadaÃÃes de ambos os impostos; ii) elevaÃÃes na taxa SELIC e nos meios de pagamento restritos (M1), diferentemente do observado no cÃmbio, tendem a proporcionar aumentos na arrecadaÃÃo de ambos os impostos. Em conjunto, tais resultados justificam a preocupaÃÃo e a necessidade de intervenÃÃo da autoridade monetÃria no intuito de regular o comportamento desses controles. / This work investigates the impact of the instruments of monetary and fiscal policy on the funds raised by the Federal Government and available to other federal entities (cities and states) in Brazil. The dependent variables were the Income Tax (IT), the Tax on Industrialized Products, while controls were the official interest rate (SELIC), the restricted means of payment (M1) and exchange rate (real / U.S. dollar). Traditional econometric time series models were estimated using monthly data from January 2008 to December 2012 and the results allowed to infer that: i) increases in the dollar provide decreases in both taxes; ii) increases in the interest rate and restricted means of payment (M1) tend to provide increases in both taxes. Together, these results justify the concern and the need for intervention by the monetary authority in order to regulate the behavior of these controls.

Coal mining is a significant industry in Appalachia. Herbaceous groundcovers are commonly planted to reduce soil erosion and protect water quality during mine reclamation, but many groundcovers may be too competitive to be compatible with trees. The objectives of this research were to investigate the performance of trees planted within different groundcovers and to measure how different groundcovers influence resource availability, specifically soil moisture and light Two studies were performed; one in a greenhouse and the other on 3 mine sites in east Tennessee where seedlings were planted and grown in competition with different groundcovers. Growth, biomass, leaf area, and foliar transpiration of tree seedlings, percent cover of groundcovers, percent volumetric soil moisture, and photosynthetically active radiation (PAR) were measured. In the greenhouse, root-to-shoot ratios of northern red oak seedlings in the presence of competition from switchgrass and in bare treatments were found to be greater than in alfalfa and annual rye treatments. Specific leaf area of seedlings in the annual rye treatment was found to be lower than the other treatments. Seedlings in the bare and switchgrass treatments were found to have greater transpiration rates than in the annual rye and alfalfa treatments. On the mine sites, growth and transpiration of northern red oak, American chestnut, black cherry, and shagbark hickory seedlings did not differ among groundcover treatments. In both studies, percent soil moisture was found to be greatest in the bare and switchgrass treatments, and percent full PAR at 14 cm was found to be greatest in the bare treatment. In the greenhouse, percent full PAR was lowest in the switchgrass treatment and was lowest in the alfalfa treatment in the field. Many factors may explain differences in seedling growth and performance between the greenhouse study and the field study such as tremendous variability in substrates and percent groundcover in the field, micro-site influence, and other unknown factors. Results from this study suggest that of the groundcover species studied, switchgrass may be the most compatible with the hardwoods studied, but more research is warranted to definitively determine the competitive interactions between the tree and groundcover species studied.

Este trabalho propõe uma heurística construtiva determinística e uma heurística construtiva probabilística para resolver o problema de programação de projetos com custo de disponibilidade de recursos e custo de penalidade por atraso no término do projeto (RACPT - Resource Availability Cost Problem with Tardiness). Os algoritmos combinam a flexibilidade da atividade com a flexibilidade do recurso para selecionar a próxima atividade a ser programada. A data de início de uma atividade é a data mais cedo em que sua execução não gera o maior pico de utilização dos recursos ou a data mais cedo na qual o custo total do projeto for menor. A melhor versão das heurísticas foi obtida após o teste de várias regras de prioridade, conforme a revisão bibliográfica realizada. As heurísticas propostas foram testadas em 360 instâncias de testes e seus resultados foram comparados aos obtidos pela formulação matemática baseada em strip packing e restrições disjuntivas implementada no programa CPLEX. A heurística construtiva determinística gera uma solução viável rapidamente, porém de baixa qualidade. Já a heurística construtiva probabilística gera soluções ótimas ou próximas da ótima para problemas pequenos ou para problemas fáceis e gera soluções muito melhores do que o CPLEX na metade do tempo computacional para os problemas médios e grandes ou para problemas difíceis. Dado os bons resultados obtidos e à implementação no programa VBA for Microsoft Excel, a heurística construtiva probabilística proposta é um método bom e prático para resolução do RACPT. / This work proposes a deterministic constructive heuristic and a probabilistic constructive heuristic for solving the resource availability cost problem with tardiness (RACPT). The algorithms combine the flexibility of an activity with the flexibility of a resource to select the next activity to be scheduled. The start time of the activity is the earliest date in which the activity\'s execution does not create resources usage peak or the earliest date with the lowest total project cost. We tested several priority rules according to the literature review and determined the best version of the heuristics. Afterwards, we tested the proposed heuristics in 360 instances and compared its results with the solutions obtained by the optimization software CPLEX. The RACPT implementation on CPLEX utilized a mathematical formulation based on strip packing concepts and disjunctive constraints. The computational results showed that the deterministic constructive heuristic generates feasible solutions of poor quality in low computational time. The probabilistic constructive heuristic achieved better results. For small instances or easy problems, it found optimal or near-optimal solutions. For medium and large instances or hard problems, it obtained better results than CPLEX in half-computational time. We believe that the probabilistic constructive heuristic is a good and practical method for solving the RACPT. The proposed algorithm produced good results in reasonable computational time and was implemented on the popular software VBA for Microsoft Excel.