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Quantifying Vein Patterns in Growing LeavesAssaf, Rebecca 16 May 2011 (has links)
How patterns arise from an apparently uniform group of cells is one of the classical problems in developmental biology. The mechanism is complicated by the fact that patterning occurs on a growing medium. Therefore, changes in an organism’s size and shape affect the patterning processes. In turn, patterning itself may affect growth. This interaction between growth and patterning leads to the generation of complex shapes and structures from simpler ones. Studying such interactions requires the possibility to monitor both processes in vivo. To this end, we developed a new technique to monitor and quantify vein patterning in a growing leaf over time using the leaves of Arabidopsis thaliana as a model system. We used a transgenic line with fluorescent markers associated with the venation. Individual leaves are followed in many samples in vivo through time-lapse imaging. Custom-made software allowed us to extract the leaf surface and vein pattern from images of each leaf at each time point. Then average spatial maps from multiple samples that were generated revealed spatio-temporal gradients. Our quantitative description of wild type vein patterns during leaf development revealed that there is no constant size at which a part of tissue enclosed by vasculature will become irrigated by a new vein. Instead, it seemed that vein formation depends on the growth rate of the tissue. This is the first time that vein patterning in growing leaves was quantified. The techniques developed will later be used to explore the interaction between growth and patterning through a variety of approaches, including mutant analysis, pharmacological treatments and variation of environmental conditions.
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Quantifying Vein Patterns in Growing LeavesAssaf, Rebecca 16 May 2011 (has links)
How patterns arise from an apparently uniform group of cells is one of the classical problems in developmental biology. The mechanism is complicated by the fact that patterning occurs on a growing medium. Therefore, changes in an organism’s size and shape affect the patterning processes. In turn, patterning itself may affect growth. This interaction between growth and patterning leads to the generation of complex shapes and structures from simpler ones. Studying such interactions requires the possibility to monitor both processes in vivo. To this end, we developed a new technique to monitor and quantify vein patterning in a growing leaf over time using the leaves of Arabidopsis thaliana as a model system. We used a transgenic line with fluorescent markers associated with the venation. Individual leaves are followed in many samples in vivo through time-lapse imaging. Custom-made software allowed us to extract the leaf surface and vein pattern from images of each leaf at each time point. Then average spatial maps from multiple samples that were generated revealed spatio-temporal gradients. Our quantitative description of wild type vein patterns during leaf development revealed that there is no constant size at which a part of tissue enclosed by vasculature will become irrigated by a new vein. Instead, it seemed that vein formation depends on the growth rate of the tissue. This is the first time that vein patterning in growing leaves was quantified. The techniques developed will later be used to explore the interaction between growth and patterning through a variety of approaches, including mutant analysis, pharmacological treatments and variation of environmental conditions.
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Quantifying Vein Patterns in Growing LeavesAssaf, Rebecca 16 May 2011 (has links)
How patterns arise from an apparently uniform group of cells is one of the classical problems in developmental biology. The mechanism is complicated by the fact that patterning occurs on a growing medium. Therefore, changes in an organism’s size and shape affect the patterning processes. In turn, patterning itself may affect growth. This interaction between growth and patterning leads to the generation of complex shapes and structures from simpler ones. Studying such interactions requires the possibility to monitor both processes in vivo. To this end, we developed a new technique to monitor and quantify vein patterning in a growing leaf over time using the leaves of Arabidopsis thaliana as a model system. We used a transgenic line with fluorescent markers associated with the venation. Individual leaves are followed in many samples in vivo through time-lapse imaging. Custom-made software allowed us to extract the leaf surface and vein pattern from images of each leaf at each time point. Then average spatial maps from multiple samples that were generated revealed spatio-temporal gradients. Our quantitative description of wild type vein patterns during leaf development revealed that there is no constant size at which a part of tissue enclosed by vasculature will become irrigated by a new vein. Instead, it seemed that vein formation depends on the growth rate of the tissue. This is the first time that vein patterning in growing leaves was quantified. The techniques developed will later be used to explore the interaction between growth and patterning through a variety of approaches, including mutant analysis, pharmacological treatments and variation of environmental conditions.
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Quantifying Vein Patterns in Growing LeavesAssaf, Rebecca January 2011 (has links)
How patterns arise from an apparently uniform group of cells is one of the classical problems in developmental biology. The mechanism is complicated by the fact that patterning occurs on a growing medium. Therefore, changes in an organism’s size and shape affect the patterning processes. In turn, patterning itself may affect growth. This interaction between growth and patterning leads to the generation of complex shapes and structures from simpler ones. Studying such interactions requires the possibility to monitor both processes in vivo. To this end, we developed a new technique to monitor and quantify vein patterning in a growing leaf over time using the leaves of Arabidopsis thaliana as a model system. We used a transgenic line with fluorescent markers associated with the venation. Individual leaves are followed in many samples in vivo through time-lapse imaging. Custom-made software allowed us to extract the leaf surface and vein pattern from images of each leaf at each time point. Then average spatial maps from multiple samples that were generated revealed spatio-temporal gradients. Our quantitative description of wild type vein patterns during leaf development revealed that there is no constant size at which a part of tissue enclosed by vasculature will become irrigated by a new vein. Instead, it seemed that vein formation depends on the growth rate of the tissue. This is the first time that vein patterning in growing leaves was quantified. The techniques developed will later be used to explore the interaction between growth and patterning through a variety of approaches, including mutant analysis, pharmacological treatments and variation of environmental conditions.
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Demands of Autonomous Vehicles on Urban Infrastructure : A Study of required transformations and global adaptability to AVsWaqas, Apsara, Shishore, Esayas January 2021 (has links)
This paper aims to assess the limits of urban fabric for the autonomous vehicles and demands of AVs on the infrastructure. It includes the existing road situation and required transformation for successful adaptability of this smart mobility in future. It is predictable that the cities ought to be reshaped before this advanced autonomous technology takes over our roads and makes the current vehicular mobility less popular or perhaps obsolete. To host AV´s, the future city will have to be smart and data-driven. This paper also discusses different aspects of autonomous vehicle technology and their suitability. For the roads and networks to be suitable for self-driving vehicles, the infrastructure will surely be upgraded according to the level of automation that will rule the roads in a specific location. Three standard models are developed in attempt to create different scenarios for successful operation of driverless cars on roads of various functional natures. First of all, the paper introduces the concept of smart cities and its components. Then it unfolds the technological aspects of autonomous mobility and its related challenges. After a brief overview of the basic concepts, the paper primarily discusses the demands of autonomous vehicles on infrastructure in terms of standard road widths, lanes, geometry, complexity, parking needs and trafficability. The paper further proceeds with case studies from three different geographical locations. The model scenarios are implemented on these cities to evaluate possibility of their existing infrastructure to accommodate self-driving cars. These hybrid model scenarios are crucially important part of this research as they contribute to final conclusions and suggestions. However, they need further development and work in near future for further research in this field.
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Cálculo de perdas técnicas em sistemas de distribuição - modelos adequáveis às características do sistema e à disponibilidade de informações. / Technical losses estimation in distribution systems - adaptative models to the system characteristics and availability of information.André Méffe 19 December 2006 (has links)
Este trabalho tem por objetivo apresentar e discutir alguns modelos para cálculo de perdas técnicas e não técnicas em sistemas de distribuição, considerando diversas alternativas em função da disponibilidade de dados. A discussão é de fundamental importância, na medida que o setor elétrico passa a enfrentar novos desafios, tais como o cálculo de redes de baixa tensão com cadastro incompleto e o cálculo de perdas não técnicas com sua respectiva parcela de perdas técnicas. Para o cálculo das perdas em redes de baixa tensão com cadastro incompleto, duas situações são consideradas. Na primeira, a rede é conhecida, porém não se conhece a localização de seus consumidores. Na segunda situação, também a rede é desconhecida. Neste último caso, para superar o problema de ausência de informações, são utilizadas técnicas de classificação para definir um conjunto de padrões de redes típicas e posterior associação de cada rede a um padrão previamente estabelecido. Também são utilizados alguns modelos de distribuição da carga e a consideração de incertezas é contemplada a partir de números difusos. Para calcular as perdas não técnicas com sua respectiva parcela de perdas técnicas, propõe-se um método para corrigir a energia faturada dos consumidores a partir do conhecimento da energia medida e das perdas técnicas calculadas. Uma extensão desse método ainda permite calcular as perdas de forma rápida e sem grandes esforços computacionais (método expedito), partindo do resultados de um cálculo realizado com um método convencional. Todos os modelos propostos são aplicados a redes de distribuição reais. Os resultados obtidos são analisados e comparados a valores de referência e é discutida a aplicabilidade dos modelos, bem como suas respectivas faixas de validade. / This work aims at presenting and discussing some models for calculating technical and non-technical losses in distribution systems. The proposed methods comprise several possibilities depending on the available data. This discussion is very important since the electric sector faces new challenges, such as technical loss estimation in low voltage networks with incomplete data. The evaluation of non-technical losses is also herein discussed. Regarding loss estimation with incomplete data, two conditions are considered. In the first one, the network data is known, but the customers location are unavailable. In the second one, the network data is not completely known as well. In this latter condition, in order to overcome the lack of sufficient data, classification techniques are used to establish a set of typical network patterns and to associate each network to a previously established pattern. Some load distribution models are also used and the uncertainties are considered by the use of fuzzy sets. In order to estimate the non-technical losses and their related technical losses, a method to adjust the billed energy in all customers is proposed. This is accomplished by using the computed technical losses and the measured energy at the substation site. This method also makes possible the assessment of technical losses in a quick way with a low computational effort (fast method). Such method is accomplished by using the results of a calculation previously performed using the conventional method. All the proposed methods are applied to real distribution networks. The obtained results are discussed and compared to the results obtained with the conventional method. The applicability of each model is also discussed.
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Cálculo de perdas técnicas em sistemas de distribuição - modelos adequáveis às características do sistema e à disponibilidade de informações. / Technical losses estimation in distribution systems - adaptative models to the system characteristics and availability of information.Méffe, André 19 December 2006 (has links)
Este trabalho tem por objetivo apresentar e discutir alguns modelos para cálculo de perdas técnicas e não técnicas em sistemas de distribuição, considerando diversas alternativas em função da disponibilidade de dados. A discussão é de fundamental importância, na medida que o setor elétrico passa a enfrentar novos desafios, tais como o cálculo de redes de baixa tensão com cadastro incompleto e o cálculo de perdas não técnicas com sua respectiva parcela de perdas técnicas. Para o cálculo das perdas em redes de baixa tensão com cadastro incompleto, duas situações são consideradas. Na primeira, a rede é conhecida, porém não se conhece a localização de seus consumidores. Na segunda situação, também a rede é desconhecida. Neste último caso, para superar o problema de ausência de informações, são utilizadas técnicas de classificação para definir um conjunto de padrões de redes típicas e posterior associação de cada rede a um padrão previamente estabelecido. Também são utilizados alguns modelos de distribuição da carga e a consideração de incertezas é contemplada a partir de números difusos. Para calcular as perdas não técnicas com sua respectiva parcela de perdas técnicas, propõe-se um método para corrigir a energia faturada dos consumidores a partir do conhecimento da energia medida e das perdas técnicas calculadas. Uma extensão desse método ainda permite calcular as perdas de forma rápida e sem grandes esforços computacionais (método expedito), partindo do resultados de um cálculo realizado com um método convencional. Todos os modelos propostos são aplicados a redes de distribuição reais. Os resultados obtidos são analisados e comparados a valores de referência e é discutida a aplicabilidade dos modelos, bem como suas respectivas faixas de validade. / This work aims at presenting and discussing some models for calculating technical and non-technical losses in distribution systems. The proposed methods comprise several possibilities depending on the available data. This discussion is very important since the electric sector faces new challenges, such as technical loss estimation in low voltage networks with incomplete data. The evaluation of non-technical losses is also herein discussed. Regarding loss estimation with incomplete data, two conditions are considered. In the first one, the network data is known, but the customers location are unavailable. In the second one, the network data is not completely known as well. In this latter condition, in order to overcome the lack of sufficient data, classification techniques are used to establish a set of typical network patterns and to associate each network to a previously established pattern. Some load distribution models are also used and the uncertainties are considered by the use of fuzzy sets. In order to estimate the non-technical losses and their related technical losses, a method to adjust the billed energy in all customers is proposed. This is accomplished by using the computed technical losses and the measured energy at the substation site. This method also makes possible the assessment of technical losses in a quick way with a low computational effort (fast method). Such method is accomplished by using the results of a calculation previously performed using the conventional method. All the proposed methods are applied to real distribution networks. The obtained results are discussed and compared to the results obtained with the conventional method. The applicability of each model is also discussed.
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