Browsing by Issue Date, starting with "2012-09"
Now showing 1 - 10 of 15
Results Per Page
Sort Options
- Using Nonlinear Static Procedures for the Seismic Assessment of Irregular RC BuildingsPublication . Sousa, Romain; Eroglu, T; Kazantzidou, D.; Kohrangi, M.; Sousa, L.; Nascimbene, Roberto; Pinho, R.The application of Nonlinear Static Procedures (NSPs) to assess the seismic vulnerability of existing structures has become widely accepted and extensively used in the literature as well as in engineering practice. Nevertheless, their success in predicting the response of irregular buildings is not yet fully verified. The main goal of the present study is to evaluate the capability and accuracy of some of the existing nonlinear static procedures (N2 and ACSM, in this case) to estimate the seismic performance of irregular structures. In order to accomplish this objective, four existing buildings, irregular in plan and elevation, were subjected to an extensive number of nonlinear static and dynamic analyses. The comparisons, focused on both global and local response parameters provide first indications on the reliability of static procedures to estimate the actual response of irregular RC buildings.
- Controlo da qualidade e segurança alimentar do polvo - Octopus VulgarisPublication . Pereira, MarcelA captura do polvo-comum (Octopus vulgaris) em Portugal apresenta uma enorme importância económica por ser uma das 5 espécies mais comercializadas em lota em todo o continente (Docapesca, 2012). Com o aparecimento da ASAE – Autoridade de Segurança Alimentar e Económica em 2006 através do Decreto-Lei nº 237/2005, de 30/12, e tendo em consideração o seu modo bastante activo de actuação foram tornadas públicas inúmeras situações que colocaram em causa a qualidade assim como a segurança alimentar dos alimentos (ASF – ASAE, 2009). Desde então o consumidor tem vindo a demonstrar uma voz ativa no que respeita à qualidade e segurança alimentar, sendo esta uma situação impulsionadora para a elaboração desta dissertação, assim como a necessidade de elaboração de estudos ao nível da qualidade e segurança alimentar em cefalópodes a nível nacional. Os objectivos da presente dissertação passam pela avaliação da qualidade microbiológica e química, assim como do índice de frescura adaptado ao polvo por Vaz-Pires & Barbosa (2004). Comparar a qualidade e segurança alimentar do polvo Octopus Vulgaris à saída da lota com o polvo-comum Octopus Vulgaris que se encontra disponível ao consumidor final na grande distribuição, avaliando o possível decréscimo de qualidade ao longo do tempo. Verificar se existe uma relação direta entre a contaminação do gelo utilizado na refrigeração e a contaminação presente nos mesmos, de acordo com estudo desenvolvido no âmbito do Projeto Lotaçor 2011 (Geada et al., 2011). Os resultados permitem concluir que o polvo-comum – Octopus Vulgaris transacionado na lota de Peniche, assim como o vendido na grande distribuição ao nível local são de elevada qualidade, contudo existe uma necessidade emergente de implementar/cumprir códigos boas práticas de higiene no sector especialmente na venda em lota.
- Effect of Different Modelling Assumptions on the Seismic Response of RC StructuresPublication . Sousa, Romain; Eroglu, T; Kazantzidou, D.; Kohrangi, M.; Sousa, Luís; Nascimbene, Roberto; Pinho, RuiThe introduction of new regulations for seismic assessment of structures established stricter performance requirements for existing buildings. In order to account for the poor seismic behaviour of such buildings, recent seismic codes, namely Eurocode 8 (EC8), introduce a number of prescriptions regarding issues such as analysis type, load distribution, accidental eccentricity, etc. At the same time, these codes give room for engineering judgment to be used with reference to the definition of structural and non-structural elements such as slabs or infill walls, and obviously leave the modelling assumptions, such as Finite Elements typology, meshing, mass modelling, etc. to the analyst decision. As such, four existing RC buildings, representative of traditional Mediterranean construction, considering different modelling assumptions, were subjected to an extensive number of nonlinear static analyses. The interpretation of possible deviations in the results will hopefully provide indications on the relative importance of each modelling parameter or decision.
- Federalismo Na União EuropeiaPublication . Lucas, EugénioNa UE - União Europeia o federalismo esteve presente de uma forma muito clara na sua origem. A palavra “federalismo” não surgiu nos Tratados constitutivos, mas no espírito de muitos dos fundadores era esse o projecto. Neste artigo pretendemos, recorrendo a análise de bibliografia de referência, investigar se existe ou não federalismo na UE. O processo de crescimento da UE, de avanços e recuos, sem uma linha de orientação bem definida, com discussão quanto à sua natureza e das suas instituições é muito idêntica ao que aconteceu nos EUA, no período entre 1789 e o fim da guerra civil.
- A psicologia do esporte na formação de técnicos desportivosPublication . Dias, Isabel SimõesEste artigo procura dar a conhecer a metodologia de ensino/aprendizagem utilizada na unidade curricular de Psicologia do Esporte do 2.º ano do curso de formação inicial de Esporte e Bem Estar (Instituto Politécnico de Leiria – Escola Superior de Educação e Ciências Sociais) no ano letivo 2010/2011. Adotando-se uma metodologia ativa, incentivou-se a avaliação contínua focalizada na participação nas sessões, na avaliação individual e na realização de um trabalho de grupo. De um universo de 82 estudantes, 43 optaram pela avaliação contínua, tendo sido realizados 14 trabalhos. Neste contexto, propomo-nos partilhar os dados dos trabalhos de grupo de índole investigativo e o percurso formativo dos estudantes na sua elaboração.
- Evaluation of Analytical Methodologies to Derive Vulnerability FunctionsPublication . Silva, Vitor; Varum, Humberto; Crowley, Helen; Sousa, Romain; Pinho, RuiThe recognition of fragility functions as a fundamental tool in seismic risk assessment has led to the development of more and more complex and elaborate procedures for their computation. Although vulnerability functions have been traditionally produced using observed damage and loss data, more recent studies propose the employment of analytical methodologies as a way to overcome the frequent lack of post-earthquake data. The variation of the structural modelling approaches on the estimation of building capacity has been the target of many studies in the past, however, its influence in the resulting vulnerability model, impact in loss estimations or propagation of the uncertainty to the seismic risk calculations has so far been the object of restricted scrutiny. Hence, in this paper, an extensive study of static and dynamic procedures for estimating the nonlinear response of buildings has been carried out in order to evaluate the impact of the chosen methodology on the resulting vulnerability and risk outputs. Moreover, the computational effort and numerical stability provided by each approach were evaluated and conclusions were obtained regarding which one offers the optimal balance between accuracy and complexity.
- Aesthetic Terrain Programs database for creativity assessmentPublication . Frade, Miguel; Vega, F. Fernandez de; Cotta, CarlosTo speed up content creation video game industry is increasingly turning to procedural content generation methods. However, creating and fine tuning procedural algorithms is a time consuming task. To address this issue several Search-Based Procedural Content Generation (SBPCG) techniques have been devised. They propose to automatically search the right input parameters or to generate the procedure itself to produce content with the desired characteristics. In this paper we present a database with 17820 procedures generated by Genetic Terrain Programming (GTP), a SBPCG technique. Those procedures were evolved using the weighted sum of two morphological metrics to generate terrains with aesthetic appeal for video games. With this database we aim to establish a comparison base for future research regarding creativity of GTP and aesthetic terrains diversity.
- Inter-vehicle sensor fusion for accurate vehicle localization supported by V2V and V2I communicationsPublication . Conde Bento, Luis; Parafita, Ricardo; Nunes, UrbanoCooperative driving system techniques aim to minimize accidents, traffic congestion and consequently the environmental costs of road traffic. An accurate vehicle's pose is of extreme importance for the inner working of the traffic management systems. An agent based traffic simulator was developed integrating typical automotive sensors, vehicle-tovehicle (V2V) and vehicle-to-infrastructure (V2I) communications, vehicle's agent and infrastructure agent. In this paper, we propose to further enhance a multi-sensor localization algorithm in environments where V2V and V2I communication is possible. This paper describes an inter-vehicle sensor fusion for an accurate vehicle positioning, where each vehicle is modeled by an agent, and each agent provides information depending on its vehicle sensors. In the first fusion stage, data from four wheel encoders and one steering encoder are fused by means of an EKF, providing robust odometric information, namely in face of undesirable effects of wheels slippage. Next, a second fusion stage is processed for integrating odometric and inter-vehicle absolute positioning data.
- Intelligent traffic management at intersections supported by V2V and V2I communicationsPublication . Conde Bento, Luis; Parafita, Ricardo; Nunes, UrbanoThis paper describes an intelligent traffic management system applied to road intersections, namely round-about and crossroads. A microscopic traffic simulator was developed to study intelligent traffic management techniques and evaluate their performance. The intelligent management techniques are aimed to minimize accidents, traffic congestion and consequently the environmental costs of road traffic. Each vehicle is modeled by an agent and each agent provides information depending on its vehicle sensors. Two intersection types, roundabout and crossroads, were simulated each using its intelligent traffic management system. Both intersections use an algorithm based on a spatio-temporal reservation scheme. The envisioned intelligent traffic management algorithm is supported by vehicle-to-vehicle and vehicle-to-infrastructure communications, allowing the exchange of information between vehicles and the intersection intelligent traffic management system. The developed intelligent traffic management system is very well suited for autonomous vehicles, it can also be used by human drivers if they follow accurately the proposed speed profile along the path.
- Efficient depth map coding using linear residue approximation and a flexible prediction frameworkPublication . Lucas, Luis F. R.; Rodrigues, Nuno M. M.; Pagliari, Carla L.; Silva, Eduardo A. B. da; Faria, Sérgio M. M. deThe importance to develop more efficient 3D and multiview data representation algorithms results from the recent market growth for 3D video equipments and associated services. One of the most investigated formats is video+depth which uses depth image based rendering (DIBR) to combine the information of texture and depth, in order to create an arbitrary number of views in the decoder. Such approach requires that depth information must be accurately encoded. However, methods usually employed to encode texture do not seem to be suitable for depth map coding. In this paper we propose a novel depth map coding algorithm based on the assumption that depth images are piecewise-linear smooth signals. This algorithm is designed to encode sharp edges using a flexible dyadic block segmentation and hierarchical intra-prediction framework. The residual signal from this operation is aggregated into blocks which are approximated using linear modeling functions. Furthermore, the proposed algorithm uses a dictionary that increases the coding efficiency for previously used approximations. Experimental results for depth map coding show that synthesized views using the depth maps encoded by the proposed algorithm present higher PSNR than their counterparts, demonstrating the method’s efficiency.