Comparison of inverse planning systems based on biological or physical factors: Pinnacle®, Corvus® and Monaco®

Radiotherapy (RT) is one of the most important approaches in the treatment of cancer and its performance can be improved in three different ways: through the optimization of the dose distribution, by the use of different irradiation techniques or through the study of radiobiological initiatives. The first is purely physical because is related to the physical dose distributiuon. The others are purely radiobiological because they increase the differential effect between the tumour and the health tissues. The Treatment Planning Systems (TPS) are used in RT to create dose distributions with the purpose to maximize the tumoral control and minimize the complications in the healthy tissues. The inverse planning uses dose optimization techniques that satisfy the criteria specified by the user, regarding the target and the organs at risk (OAR’s). The dose optimization is possible through the analysis of dose-volume histograms (DVH) and with the use of computed tomography, magnetic resonance and other digital image techniques.

Maintenance of fire sprinkler systems based on the dynamic assessment of its condition

Safety is one of the major concerns of process safety engineers in most industrial facilities all over the world. To this scope, some events play an important role once the effect of their consequences can be assumed as totally undesirable. One of these events refers to the occurrence of a fire. Such event can result in catastrophic consequences for life, equipment, and continuity of activities or even leading to environmental damage. A fire protection equipment with low reliability means that this equipment are often unavailable and thus the risk of a fire increases. Maintenance of fire protection equipment is very important because this kind of systems is mostly in a dormant mode, which gives uncertainty about their operability when demanded in a real situation of fire. This article outlines the importance of tests, inspection, and maintenance operations in the context of a fire sprinkler system and proposes a methodology based on international standards and supported by test/inspection reports to correct the frequency of these actions according to the level of degradation of the components and regarding safety purposes. © 2015 American Institute of Chemical Engineers.

Otimização de estruturas de destilação azeotrópica com recurso a planeamento experimental

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Química e Biológica

Modelos de simulação em MATSim aplicados à análise de sistemas de transporte

Dissertação para obtenção do grau de Mestre em Engenharia Civil na Área de Especialização de Vias de Comunicação e Transportes

(Virtual) Agents for running electricity markets

This paper describes a multi-agent based simulation (MABS) framework to construct an artificial electric power market populated with learning agents. The artificial market, named TEMMAS (The Electricity Market Multi-Agent Simulator), explores the integration of two design constructs: (i) the specification of the environmental physical market properties and (ii) the specification of the decision-making (deliberative) and reactive agents. TEMMAS is materialized in an experimental setup involving distinct power generator companies that operate in the market and search for the trading strategies that best exploit their generating units' resources. The experimental results show a coherent market behavior that emerges from the overall simulated environment.

Estudo e desenvolvimento de um sensor de chuva piezoelétrico para automóveis

A presença de sistemas eletrónicos nos veículos automóveis tem vindo a aumentar de forma considerável nos últimos 30 anos, tornando possível o aumento dos padrões de eficiência, segurança e conforto dos mesmos. Os sistemas de acionamento automático dos limpa-para-brisas, baseados em sensores de chuva óticos, têm registado um crescimento quase exponencial nos últimos 10 a 15 anos; no ano 2000, apenas 5 % dos veículos novos produzidos na Europa estavam equipados com este sistema, hoje é um equipamento amplamente difundido na oferta automóvel existente. O presente trabalho consistiu no estudo de uma solução para deteção de chuva em veículos automóveis com a aplicação de um sensor piezoelétrico, tendo em vista a obtenção de uma solução mais versátil e aplicável em vários pontos do veículo. As reduzidas dimensões, a elevada sensibilidade do sensor e a facilidade de aplicação nas superfícies de ensaio foram fatores que motivaram a escolha deste tipo de equipamento como elemento sensorial. As hipóteses definidas para o procedimento laboratorial basearam-se nas conclusões obtidas em estudos anteriormente desenvolvidos no campo dos sensores de chuva para automóveis e nas capacidades dos materiais piezoelétricos para medição de pluviosidade. Os sensores foram instalados sob as superfícies do veículo que apresentavam, simultaneamente, uma maior exposição à pluviosidade, quando este está em movimento, e um menor risco de sofrer danos. Os resultados obtidos permitiram concluir que a utilização deste tipo de sensores permite detetar elevados níveis de pluviosidade e em superfícies com considerável capacidade de deformação elástica. A sua implementação futura em veículos automóveis exige mais algum trabalho de melhoria dos processos de fixação dos sensores e do condicionamento de sinal utilizados.

O controlo de gestão com ênfase para o Balanced Scorecard: estudo de caso sobre a implementação do Balanced Scorecard numa empresa do sector automóvel

Mestrado em Contabilidade e Gestão das Instituições Financeiras

Criação de valor - O Cash Value Added como métrica de avaliação da Performance empresarial

Mestrado em Contabilidade e Gestão das Instituições Financeiras

Análise crítica do Regulamento Geral dos Sistemas Públicos e Prediais de Distribuição de Água e de Drenagem de Águas Residuais

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Civil na Área de Especialização de Hidráulica

Estimação de cobertura rádio em GSM-R através de redes neuronais

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia de Eletrónica e Telecomunicações

Eficiência energética e controlo de iluminação em edifícios

Dissertação para obtenção do grau de Mestre em Engenharia Electrotécnica Ramo de Energia

Fractional-order control and simulation of wind energy systems with PMSG/full-power converter topology

This paper presents a new integrated model for the simulation of wind energy systems. The proposed model is more realistic and accurate, considering a variable-speed wind turbine, two-mass rotor, permanent magnet synchronous generator (PMSG), different power converter topologies, and filters. Additionally, a new control strategy is proposed for the variable-speed operation of wind turbines with PMSG/full-power converter topology, based on fractional-order controllers. Comprehensive simulation studies are carried out with matrix and multilevel power converter topologies, in order to adequately assert the system performance in what regards the quality of the energy injected into the electric grid. Finally, conclusions are duly drawn.

Power converter topologies for wind energy conversion systems: Integrated modeling, control strategy and performance simulation

This paper presents new integrated model for variable-speed wind energy conversion systems, considering a more accurate dynamic of the wind turbine, rotor, generator, power converter and filter. Pulse width modulation by space vector modulation associated with sliding mode is used for controlling the power converters. Also, power factor control is introduced at the output of the power converters. Comprehensive performance simulation studies are carried out with matrix, two-level and multilevel power converter topologies in order to adequately assert the system performance. Conclusions are duly drawn.

Hydro energy systems management in Portugal: Profit-based evaluation of a mixed-integer nonlinear approach

In this paper, a novel mixed-integer nonlinear approach is proposed to solve the short-term hydro scheduling problem in the day-ahead electricity market, considering not only head-dependency, but also start/stop of units, discontinuous operating regions and discharge ramping constraints. Results from a case study based on one of the main Portuguese cascaded hydro energy systems are presented, showing that the proposedmixed-integer nonlinear approach is proficient. Conclusions are duly drawn. (C) 2010 Elsevier Ltd. All rights reserved.

Optoelectronic Logic Functions Based on Reconfigurable SiC Multilayer Devices

WDM multilayered SiC/Si devices based on a-Si:H and a-SiC:H filter design are approached from a reconfigurable point of view. Results show that the devices, under appropriated optical bias, act as reconfigurable active filters that allow optical switching and optoelectronic logic functions development. Under front violet irradiation the magnitude of the red and green channels are amplified and the blue and violet reduced. Violet back irradiation cuts the red channel, slightly influences the magnitude of the green and blue ones and strongly amplifies de violet channel. This nonlinearity provides the possibility for selective removal of useless wavelengths. Particular attention is given to the amplification coefficient weights, which allow taking into account the wavelength background effects when a band needs to be filtered from a wider range of mixed signals, or when optical active filter gates are used to select and filter input signals to specific output ports in WDM communication systems. A truth table of an encoder that performs 8-to-1 multiplexer (MUX) function is presented.