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This thesis presents a novel distributed control method which allows a collection of independently mobile robotic units, with two or three dimensional movement, to self-assemble into self-repairing hierarchical structures. The proposed method utilises a simple model of the cellular adhesion mechanisms observed in biological cells, allowing the robotic units to form virtually bonded aggregates which behave as predicted by Steinberg’s differential adhesion hypothesis. Simulated robotic units based on the design of the subaquatic HYDRON module are introduced as a possible platform on which the model can be implemented. The units are used to carry out a detailed investigation of the model behaviour and parameter space focusing on the two main tasks of rounding and sorting in both two and three dimensions. These tasks assess the model’s ability to reach a thermodynamically stable configuration when the aggregates consist of either a single population of units or multiple populations of units with differing adhesive properties. The results are analysed in detail with particular attention given to the role of random movements in determining the overall performance, and demonstrate that this model provides a very robust solution to these complex tasks. Finally, a possible extension of this work is presented in which the original model is combined with a genetic regulatory network controller. The performance of this composite is evaluated, and the benefits of this hybrid approach, in which a powerful control system manipulates a robust self-organising behaviour, are discussed.

This thesis explains a method based on the homogenisation of zeta potential charges on carbon supports for the production of hierarchical structured zeolitic composites. The modification of carbons’ surface chemistry allowed zeolite particles to be fixed to the support by electrostatic interactions. In order to achieve this, the size reduction of zeolite particles was carried out by two different methods: a) ball milling and b) a synthetic route to produce zeolite colloidal dispersions. Also, the seeding method, based on hydrothermal growth was compared. The prepared materials in this work were designed to be used in the sorption of cations, and to allow vitrification and thereby reduce the final adsorbent volume. Results showed that a large pollutant amount can be trapped using a lower volume of material reducing costs and final waste disposal. The zeolites used in this work were selected based on their low density framework and low Si/Al ratio. Synthetic zeolites A, Y and clinoptilolite were successfully produced. Natural clinoptilolite was also utilised in this work. Also, zeolite A was produced at nanometre scale following the clear solutions method. All materials were successfully incorporated onto supports to produce multimodal porosity materials. The hierarchical modification of natural clinoptilolite, following a straightforward and nonexpensive methodology, is one the most significant contributions of this work. Carbons are used as supports due to their high surface area, they can be obtained from low-cost sources such as agroindustrial wastes and carbons allow volume reduction if materials are vitrified at high temperatures. In this work, carbons were produced from corn cob and husk, sugar cane bagasse, cherry stones, date stones and hazelnut shells. The prepared composite materials were tested in the removal of toxic ions from water solutions: cobalt, copper and caesium ions were effectively removed from aqueous media. Adsorption experiments showed that the distribution of supported zeolite particles improved their uptake efficiency and capacity. The kinetic studies revealed an enhanced rate constant for carbon-zeolites composites in comparison with pure zeolites. Diffusivity results suggested that mass transfer characteristics are modified by using hierarchical porous materials; results showed that particle size or support nature can modify diffusion resistances, reducing intraparticle diffusion and accelerating the overall kinetic processes. Adsorption equilibrium data was correlated using Langmuir and Freundlich models.

A definição das estruturas hierárquicas envolve uma estrutura que pode ser observada em escalas de diversos comprimentos, sendo que um elemento estrutural de certa escala é formado por subestruturas periódicas de uma escala menor. Utilizando o método bidirecional de otimização topológica evolucionária BESO (Bi-directional Evolutionary Structural Optimization) em estruturas contínuas compostas por materiais únicos e por vários materiais, modeladas através do método dos elementos finitos, este trabalho implementa os procedimentos computacionais necessários com o objetivo de otimizar o comportamento dinâmico do sistema estrutural, através da maximização da frequência fundamental bem como da separação de um ou dois pares de frequências adjacentes de forma simultânea ou não, sujeita a restrições de volume estrutural nas diversas fases. Cada nível hierárquico é assumido como um meio contínuo composto por um ou mais materiais homogêneos, cada um destes com uma microestrutura associada. No projeto simultâneo com múltiplas fases, as informações foram transferidas entre a micro e a macroescala através do método da homogeneização, enquanto que as técnicas de otimização topológica visaram encontrar a melhor distribuição de fases em ambas as escalas para a maximização das propriedades desejadas Dessa forma se alcançaram uma série de topologias associadas às diversas funções objetivo utilizadas, decorrentes da maximização da frequência fundamental, do intervalo entre um par de frequências naturais consecutivas, da separação das frequências naturais a partir de uma frequência prescrita e da separação de dois pares de frequências consecutivas concomitantemente. Experimentos numéricos também foram realizados buscando o melhor leiaute na macroescala, na microescala, ou em ambas de forma acoplada, apresentando-se as discussões correspondentes. Conjunto de soluções ótimas foram gerados, baseado no método dos pesos, os quais possibilitaram por exemplo a identificação da perda de integridade estrutural em alguns casos otimizados. Foram obtidas estruturas com valores de separação entre duas frequências consecutivas muito maiores do que nas topologias não otimizadas. Por exemplo quando da otimização utilizando microestrutura única com dois materiais, a maximização do intervalo entre a terceira e a segunda frequências naturais supera em aproximadamente 520% a diferença entre as mesmas frequências na topologia não otimizada. / Hierarchical structures are structures that can be observed at different length scales, where typically a structural element at a certain scale is composed by periodic substructures at a smaller scale. Applying the Bi-directional Evolutionary Structural Optimization (BESO) method to continuous structures made of a single or multiple materials modelled via the finite element method, this work implements the computational procedures needed in order to optimize the dynamic behavior of the structural system. The optimization is achieved either via maximization of the fundamental frequency, or via separation of adjacent natural frequencies, as well as via separation of one or two pairs of adjacent frequencies, simultaneously or not, all former cases subjected to volume restrictions in the different material phases. Each hierarchical level is treated as a continuous medium occupied by one or more homogeneous material, each material having an associated microstructure. In the simultaneous project with multiple phases, the information is transferred from the microstructure to the macrostructure through the homogenization method, while topology optimization techniques are employed to reach the best material distribution such that the chose objective function is maximized. In this way, a series of topologies associated to each optimization type were found, from the maximization of either the fundamental frequency, the gap between a pair of adjacent natural frequencies, the distance of all natural frequencies from a prescribed frequency, or the gap of two pairs of adjacent natural frequencies concurrently Numerical experiments were conducted in order to find the best layout for the macrostructure, microstructure, or both simultaneously via a coupled formulation. Following the results a discussion is presented. Sets of optimal solutions based on the weighed method were generated, making possible to identify the loss of structural integrity in some optimized cases. It was possible to obtain structures with separation values between two consecutive frequencies much higher than the initial values in unoptimized topologies. For example, the optimization of a single microstructure containing two materials reached a gap maximization between the third and second natural frequencies approximately 520% bigger than the difference between these same frequencies in the unoptimized topology.

Computing surface and/or object intersections is a cornerstone of many algorithms in Geometric Modeling and Computer Graphics, for example Set Operations between solids, or surface Ray Casting display. We present an object centered, information preserving, hierarchical representation for polyhedra called Prism Tree. We use the representation to decompose the intersection algorithms into two steps: the localization of intersections, and their processing. When dealing with polyhedra with many faces (typically more than one thousand), the first step is by far the most expensive. The Prism Tree structure is used to compute efficiently this localization step. A preliminary implementation of the Set Operations and Ray casting algorithms has been constructed.

<p>As the development of the Internet and the rapid increase of data, information visualization is becoming more and more popular. Since human eyes receive visual information very quick and easy, the visualization can make complex and large data more understandable.</p><p>Describing sensory perceptions, such as taste, is a challenging task. For a customer, the visualization of the taste of a specific wine together with the other wine attributes such as color and grape type would help him/her choose the right one.    In the thesis, two suitable representations of wine attributes are implemented. And, the final system contains two parts. One is a user interface generating his/her fingerprint based on the two representations. The other one is generating the fingerprints of all wines in a database, and save these fingerprints as images. If the user compares his/her wine fingerpr</p>

A definição das estruturas hierárquicas envolve uma estrutura que pode ser observada em escalas de diversos comprimentos, sendo que um elemento estrutural de certa escala é formado por subestruturas periódicas de uma escala menor. Utilizando o método bidirecional de otimização topológica evolucionária BESO (Bi-directional Evolutionary Structural Optimization) em estruturas contínuas compostas por materiais únicos e por vários materiais, modeladas através do método dos elementos finitos, este trabalho implementa os procedimentos computacionais necessários com o objetivo de otimizar o comportamento dinâmico do sistema estrutural, através da maximização da frequência fundamental bem como da separação de um ou dois pares de frequências adjacentes de forma simultânea ou não, sujeita a restrições de volume estrutural nas diversas fases. Cada nível hierárquico é assumido como um meio contínuo composto por um ou mais materiais homogêneos, cada um destes com uma microestrutura associada. No projeto simultâneo com múltiplas fases, as informações foram transferidas entre a micro e a macroescala através do método da homogeneização, enquanto que as técnicas de otimização topológica visaram encontrar a melhor distribuição de fases em ambas as escalas para a maximização das propriedades desejadas Dessa forma se alcançaram uma série de topologias associadas às diversas funções objetivo utilizadas, decorrentes da maximização da frequência fundamental, do intervalo entre um par de frequências naturais consecutivas, da separação das frequências naturais a partir de uma frequência prescrita e da separação de dois pares de frequências consecutivas concomitantemente. Experimentos numéricos também foram realizados buscando o melhor leiaute na macroescala, na microescala, ou em ambas de forma acoplada, apresentando-se as discussões correspondentes. Conjunto de soluções ótimas foram gerados, baseado no método dos pesos, os quais possibilitaram por exemplo a identificação da perda de integridade estrutural em alguns casos otimizados. Foram obtidas estruturas com valores de separação entre duas frequências consecutivas muito maiores do que nas topologias não otimizadas. Por exemplo quando da otimização utilizando microestrutura única com dois materiais, a maximização do intervalo entre a terceira e a segunda frequências naturais supera em aproximadamente 520% a diferença entre as mesmas frequências na topologia não otimizada. / Hierarchical structures are structures that can be observed at different length scales, where typically a structural element at a certain scale is composed by periodic substructures at a smaller scale. Applying the Bi-directional Evolutionary Structural Optimization (BESO) method to continuous structures made of a single or multiple materials modelled via the finite element method, this work implements the computational procedures needed in order to optimize the dynamic behavior of the structural system. The optimization is achieved either via maximization of the fundamental frequency, or via separation of adjacent natural frequencies, as well as via separation of one or two pairs of adjacent frequencies, simultaneously or not, all former cases subjected to volume restrictions in the different material phases. Each hierarchical level is treated as a continuous medium occupied by one or more homogeneous material, each material having an associated microstructure. In the simultaneous project with multiple phases, the information is transferred from the microstructure to the macrostructure through the homogenization method, while topology optimization techniques are employed to reach the best material distribution such that the chose objective function is maximized. In this way, a series of topologies associated to each optimization type were found, from the maximization of either the fundamental frequency, the gap between a pair of adjacent natural frequencies, the distance of all natural frequencies from a prescribed frequency, or the gap of two pairs of adjacent natural frequencies concurrently Numerical experiments were conducted in order to find the best layout for the macrostructure, microstructure, or both simultaneously via a coupled formulation. Following the results a discussion is presented. Sets of optimal solutions based on the weighed method were generated, making possible to identify the loss of structural integrity in some optimized cases. It was possible to obtain structures with separation values between two consecutive frequencies much higher than the initial values in unoptimized topologies. For example, the optimization of a single microstructure containing two materials reached a gap maximization between the third and second natural frequencies approximately 520% bigger than the difference between these same frequencies in the unoptimized topology.

A definição das estruturas hierárquicas envolve uma estrutura que pode ser observada em escalas de diversos comprimentos, sendo que um elemento estrutural de certa escala é formado por subestruturas periódicas de uma escala menor. Utilizando o método bidirecional de otimização topológica evolucionária BESO (Bi-directional Evolutionary Structural Optimization) em estruturas contínuas compostas por materiais únicos e por vários materiais, modeladas através do método dos elementos finitos, este trabalho implementa os procedimentos computacionais necessários com o objetivo de otimizar o comportamento dinâmico do sistema estrutural, através da maximização da frequência fundamental bem como da separação de um ou dois pares de frequências adjacentes de forma simultânea ou não, sujeita a restrições de volume estrutural nas diversas fases. Cada nível hierárquico é assumido como um meio contínuo composto por um ou mais materiais homogêneos, cada um destes com uma microestrutura associada. No projeto simultâneo com múltiplas fases, as informações foram transferidas entre a micro e a macroescala através do método da homogeneização, enquanto que as técnicas de otimização topológica visaram encontrar a melhor distribuição de fases em ambas as escalas para a maximização das propriedades desejadas Dessa forma se alcançaram uma série de topologias associadas às diversas funções objetivo utilizadas, decorrentes da maximização da frequência fundamental, do intervalo entre um par de frequências naturais consecutivas, da separação das frequências naturais a partir de uma frequência prescrita e da separação de dois pares de frequências consecutivas concomitantemente. Experimentos numéricos também foram realizados buscando o melhor leiaute na macroescala, na microescala, ou em ambas de forma acoplada, apresentando-se as discussões correspondentes. Conjunto de soluções ótimas foram gerados, baseado no método dos pesos, os quais possibilitaram por exemplo a identificação da perda de integridade estrutural em alguns casos otimizados. Foram obtidas estruturas com valores de separação entre duas frequências consecutivas muito maiores do que nas topologias não otimizadas. Por exemplo quando da otimização utilizando microestrutura única com dois materiais, a maximização do intervalo entre a terceira e a segunda frequências naturais supera em aproximadamente 520% a diferença entre as mesmas frequências na topologia não otimizada. / Hierarchical structures are structures that can be observed at different length scales, where typically a structural element at a certain scale is composed by periodic substructures at a smaller scale. Applying the Bi-directional Evolutionary Structural Optimization (BESO) method to continuous structures made of a single or multiple materials modelled via the finite element method, this work implements the computational procedures needed in order to optimize the dynamic behavior of the structural system. The optimization is achieved either via maximization of the fundamental frequency, or via separation of adjacent natural frequencies, as well as via separation of one or two pairs of adjacent frequencies, simultaneously or not, all former cases subjected to volume restrictions in the different material phases. Each hierarchical level is treated as a continuous medium occupied by one or more homogeneous material, each material having an associated microstructure. In the simultaneous project with multiple phases, the information is transferred from the microstructure to the macrostructure through the homogenization method, while topology optimization techniques are employed to reach the best material distribution such that the chose objective function is maximized. In this way, a series of topologies associated to each optimization type were found, from the maximization of either the fundamental frequency, the gap between a pair of adjacent natural frequencies, the distance of all natural frequencies from a prescribed frequency, or the gap of two pairs of adjacent natural frequencies concurrently Numerical experiments were conducted in order to find the best layout for the macrostructure, microstructure, or both simultaneously via a coupled formulation. Following the results a discussion is presented. Sets of optimal solutions based on the weighed method were generated, making possible to identify the loss of structural integrity in some optimized cases. It was possible to obtain structures with separation values between two consecutive frequencies much higher than the initial values in unoptimized topologies. For example, the optimization of a single microstructure containing two materials reached a gap maximization between the third and second natural frequencies approximately 520% bigger than the difference between these same frequencies in the unoptimized topology.

As the development of the Internet and the rapid increase of data, information visualization is becoming more and more popular. Since human eyes receive visual information very quick and easy, the visualization can make complex and large data more understandable. Describing sensory perceptions, such as taste, is a challenging task. For a customer, the visualization of the taste of a specific wine together with the other wine attributes such as color and grape type would help him/her choose the right one.    In the thesis, two suitable representations of wine attributes are implemented. And, the final system contains two parts. One is a user interface generating his/her fingerprint based on the two representations. The other one is generating the fingerprints of all wines in a database, and save these fingerprints as images. If the user compares his/her wine fingerpr

Land cover mapping is an important part of resource management, planning, and economic predictions. Improvements in remote sensing, machine learning, image processing, and object based image analysis (OBIA) has made the process of identifying land cover types increasingly faster and reliable but these advances are unable to utilize the amount of information encompassed within ultra-high (sub-meter) resolution imagery. Previously, users have typically reduced the resolution of imagery in an attempt to more closely represent the interpretation or object scale in an image and rid the image of any extraneous information within the image that may cause the OBIA process to identify too small of objects when performing semi-automated delineation of objects based on an images’ properties (Mas et al., 2015; Eiesank et al., 2014; Hu et al., 2010). There have been few known attempts to try and maximize this detailed information in high resolution imagery using advanced textural components. In this study we try to circumnavigate the inherent problems associated with high resolution imagery by combining well researched data transformations that aid the OBIA process with a seldom used texture transformation in Geographic Object Based Image Analyses (GEOBIA) known as the Gabor Transform and the hierarchal organization of landscapes. We will observe the difference made in segmentation and classification accuracy of a random forest classifier when we fuse a Gabor transformed image to a Normalized Difference Vegetation Index (NDVI), high resolution multi-spectral imagery (RGB and NIR) and Light Detection and Ranging (LiDAR) derived canopy height model (CHM) within a riparian area in Southeast Iowa. Additionally, we will observe the effects on classification accuracy when adding multi-scale land cover data to objects. Both, the addition of hierarchical information and Gabor textural information, could aid the GEOBIA process in delineating and classifying the same objects that human experts would delineate within this riparian landscape.