Looking through the eyes of the painter: from visual perception to non-photorealistic rendering

In this paper we present a brief overview of the processing in the primary visual cortex, the multi-scale line/edge and keypoint representations, and a model of brightness perception. This model, which is being extended from 1D to 2D, is based on a symbolic line and edge interpretation: lines are represented by scaled Gaussians and edges by scaled, Gaussian-windowed error functions. We show that this model, in combination with standard techniques from graphics, provides a very fertile basis for non-photorealistic image rendering.

A three-dimensional hydrodynamic model with generic vertical coordinate

A three-dimensional primitive equation model and its application to a tidal estuary is described. The model solves the primitive equations for incompressible fluids with Boussinesq and hydrostatic approximations. The discretization is based on the finite volume method and allows a general vertical coordinate. The computational code is implemented in such a way that different vertical coordinates can be used in different parts of the domain. The model was designed to be able to simulate the flow both in the open ocean and in coastal and estuarine zones and can be coupled in a simple way to ecological models. The model was implemented successfully in several estuarine and coastal areas. Results are show for the Sado estuary in Portugal to illustrate model accuracy and potential. Quantitative validation is based on field data (water levels and velocities) while qualitative verification is based on the analysis of secondary flows.

Modelação hidrológica da bacia drenante da albufeira de Pracana

O uso inadequado do solo assim como práticas agrícolas incorrectas podem ter como consequência a contaminação dos recursos hídricos por poluição de origem difusa.Na perspectiva de identificar possíveis fontes de poluição, o objectivo deste trabalho é quantificar as cargas de nutrientes de origem natural, urbana e agrícola que chegam à albufeira de Pracana. Pretende-se efectuar a análise das alterações de carga resultantes de diferentes cenários do uso do solo, recorrendo à modelação matemática. Este conhecimento vai contribuir para a compreensão dos processos que dão origem à poluição existente na albufeira e os factores que condicionam o seu estado trófico.A ferramenta utilizada para a realização do estudo foi o modelo SWAT (Soil Water Assessment Tool, USDA Agricultural Research Service).

ECTS o euro dos créditos

A Comunidade Europeia tem vindo a incentivar a cooperação entre instituições de ensino superior como uma forma de melhoramento da qualidade do ensino, com os correspondentes benefícios para os estudantes e para estas instituições. A mobilidade de estudantes é um elemento predominante desta cooperação, a qual, dentro da Europa, é organizada em torno do programa Socrates/Erasmus (European Community Action System for the Mobility of University Students). O sucesso deste programa fez com que o mesmo fosse, a partir do ano académico de 1992/93, alargado á cooperação com qualquer país pertencente à Associação Europeia de Comércio Livre (EFTA).

A methodology to estimate the residence time of estuaries

The residence time has long been used as a classification parameter for estuaries and other semi- enclosed water bodies. It aims to quantify the time water remains inside the estuary, being used as an indicator both for pollution assessment and for ecological processes. Estuaries with a short residence time will export nutrients from upstream sources more rapidly then estuaries with longer residence time. On the other hand the residence time determines if micro-algae can stay long enough to generate a bloom. As a consequence, estuaries with very short residence time are expected to have much lower algae blooms, then estuaries with longer residence time. In addition, estuaries with residence times shorter than the doubling time of algae cells will inhibit formation of algae blooms (EPA, 2001). The residence time is also an important issue for processes taking place in the sediment. The fluxes of particulate matter and associated adsorbed species from the water column to the sediment depends of the particle’s vertical velocity, water depth and residence time. This is particularly important for the fine fractions with lower sinking velocities. The question is how to compute the residence time and how does it depend on the computation method adopted.

Valorização de aguardentes de fruto e licores tradicionais como suporte de desenvolvimento na Serra Algarvia

Durante séculos, os segredos envolvidos no fabrico de produtos tradicionais, passaram verbalmente de geração em geração. Contudo, a busca de melhores condições sociais levou, nas últimas décadas, ao desenvolvimento de grandes centros urbanos, onde praticamente tudo o que se consome provém de outras regiões do país ou do estrangeiro.

SIC and PIC multiuser detection for prefix-assisted DS-CDMA systems

In this paper we present iterative frequency-domain multiuser detection (MUD) receivers for the uplink transmission of direct sequence code division multiple access systems (DS-CDMA) that combine iterative block decision feedback equalization (IB-DFE) principles with interference cancelation techniques. Both successive interference cancelation (SIC) and parallel interference cancelation (PIC) structures are considered. Our performance results show that the proposed receiver structures have excellent bit error rate (BER) performances, that can be close to the single-user matched filter bound (MFB), even for fully loaded systems and severely time-dispersive channels1.

Fast segmentation of 3D data using an octree

The algorithm developed uses an octree pyramid in which noise is reduced at the expense of the spatial resolution. At a certain level an unsupervised clustering without spatial connectivity constraints is applied. After the classification, isolated voxels and insignificant regions are removed by assigning them to their neighbours. The spatial resolution is then increased by the downprojection of the regions, level by level. At each level the uncertainty of the boundary voxels is minimised by a dynamic selection and classification of these, using an adaptive 3D filtering. The algorithm is tested using different data sets, including NMR data.

Spatial and temporal assessment of sediment contamination in Sado estuary: a methodological approach

For better management of estuarine ecosystems their contamination assessment should be easily communicated to local managers and decision makers. The problem is the lack of available data and the search of methodologies to enable that assessment using only few data. The Sado estuary in Portugal is as good example of a site where human pressures and ecological values collide with each other and where the degree of metal and organic contamination has not been subject to an overall assessment, either in terms of spatial or temporal variability, in a way that managers can understand.

Region segregation and saliency using colour information

Saliency maps determine the likelihood that we focus on interesting areas of scenes or images. These maps can be built using several low-level image features, one of which having a particular relevance: colour. In this paper we present a new computational model, based only on colour features, which provides a sound basis for saliency maps for static images and video, plus region segregation and cues for local gist vision.

Análise comparativa da casualidade sísmica do Algarve

In this paper we compared the seismic hazard of Algarve obtained with two different models: a point-source model (proposed by McGuire) and a fault-rupture model (proposed by Der Kiureghian and Ang).

Modelação hidrodinâmica de escoamentos costeiros

As zonas costeiras, os estuários e os sistemas lagunares são regiões de elevada importância do ponto de vista económico devido à intensa actividade nelas desenvolvida. Encontram-se por esse motivo sujeitas a fortes pressões do tipo ambiental. A correcta gestão dos seus recursos deve ser apoiada em ferramentas que possibilitem uma análise precisa dos fenómenos que nelas ocorrem e permitam a previsão da evolução desses sistemas. A recente evolução na capacidade de cálculo dos computadores de pequeno porte tornou viável a utilização de modelos hidrodinâmicos como ferramentas de apoio à decisão.

Simulating water mixing in a barotropic estuary: the effect of vertical discretization

Mixing between estuarine and coastal waters is strongly dependent on the processes that occur in the vertical direction. This applies both for stratified and homogeneous estuaries. In homogeneous estuaries important recirculation flows in the vertical plane can arise, in regions with strong batimetry gradients, produced by the combined action of inertia and friction. On the Platform close to the inlet this structures can trap estuarine water during the ebb period, releasing it to the interior again during the flood.

Início do estudo do envelhecimento da aguardente de medronho

A cor nos destilados indica geralmente um prévio envelhecimento. Os consumidores associam tal facto a um produto de qualidade. Refiram-se os casos dos whiskies e dos brandies. A aguardente de medronho não foge à regra, sendo preferida nos casos em que apresenta cor. No entanto a qualidade deve ser confirmada pelo aroma e sabor, bem como pelas análises químicas. Com efeito, o processo da obtenção da cor nem sempre é o mais adequado. Com o duplo objectivo de estudar o processo mais adequado para obter uma aguardente medronheira velha de qualidade e de a tipificar de modo a identificar eventuais fraudes, a Escola Superior de Tecnologia da Universidade do Algarve (EST-UAlg) em parceria com a Direcção Regional de Agricultura do Algarve (DRAALG) candidataram-se a um projecto PAMAF-IE

Influência da modelação de elementos não estruturais no dimensionamento à acção sísmica

Realizou-se um estudo paramétrico sobre a influência de elementos não estruturais, executados em betão, no dimensionamento de elementos estruturais de betão armado, face às acções sísmicas regulamentares.