Contribution of the evaluation strategy and the use of hearing protection for the uncertainty associated with occupational exposure to noise

Doctoral Thesis for PhD degree in Industrial and Systems Engineering

A geographic opportunistic forwarding strategy for vehicular named data networking

Studies in Computational Intelligence, 616

Specification and testing of multiplicative time-varying GARCH models with applications

In this article, we develop a specification technique for building multiplicative time-varying GARCH models of Amado and Teräsvirta (2008, 2013). The variance is decomposed into an unconditional and a conditional component such that the unconditional variance component is allowed to evolve smoothly over time. This nonstationary component is defined as a linear combination of logistic transition functions with time as the transition variable. The appropriate number of transition functions is determined by a sequence of specification tests. For that purpose, a coherent modelling strategy based on statistical inference is presented. It is heavily dependent on Lagrange multiplier type misspecification tests. The tests are easily implemented as they are entirely based on auxiliary regressions. Finite-sample properties of the strategy and tests are examined by simulation. The modelling strategy is illustrated in practice with two real examples: an empirical application to daily exchange rate returns and another one to daily coffee futures returns.

Three-phase three-level current-source converter for EVs fast battery charging systems

This paper presents a three-phase three-level fast battery charger for electric vehicles (EVs) based in a current-source converter (CSC). Compared with the traditional voltage-source converters used for fast battery chargers, the CSC can be seen as a natural buck-type converter, i.e., the output voltage can assume a wide range of values, which varies between zero and the maximum instantaneous value of the power grid phase-to-phase voltage. Moreover, using the CSC it is not necessary to use a dc-dc back-end converter in the battery side, and it is also possible to control the grid current in order to obtain a sinusoidal waveform, and in phase with the power grid voltage (unitary power factor). Along the paper is described in detail the proposed CSC for EVs fast battery charging systems: the circuit topology, the power control theory, the current control strategy and the grid synchronization algorithm. Several simulation results of the EV fast battery charger operating with a maximum power of 50 kW are presented.

Three-phase current-source shunt active power filter with solar photovoltaic grid interface

This paper presents the proposal of a three phase current source shunt active power filter (CS-SAPF) with photovoltaic grid interface. The proposed system combines the compensation of reactive power and harmonics with the injection of energy from a solar photovoltaic array into the electrical power grid. The proposed equipment presents the advantage of giving good use to the current source inverter, even when the solar photovoltaic array is not producing energy. The paper describes the control system of the CS SAPF, the energy injection control strategy, and the current harmonics and power factor compensation strategy. Simulation results to assess the performance of the proposed system are also presented.

O lúdico como estratégia de consolidação e revisão de conhecimentos na aula de Língua Estrangeira

Relatório de estágio de mestrado em Ensino do Português no 3º Ciclo do Ensino Básico e no Ensino Secundário e de Espanhol nos Ensinos Básico e Secundário

Documentação pedagógica: estratégia de escuta e resposta a diferentes interesses em interação

Relatório de estágio de mestrado em Educação Pré-Escolar

A comunicação do compromisso para com o desenvolvimento sustentável, das organizações portuguesas certificadas em qualidade, ambiente e segurança

Dissertação de mestrado em Engenharia Industrial (área de especialização em Qualidade, Segurança e Manutenção)

Using balanced scorecards to evaluate the data warehouse system utility

Dissertação de mestrado em Systems Engineering

Innovation in “low-tech” industries: Portuguese footwear industry

ICEIM – International Conference in Entrepreneurship and Innovation Management, Roma, 17-18 de setembro de 2015.

Desenvolvimento de um filtro ativo paralelo com CSI e controlo de corrente no barramento CC

Dissertação de mestrado integrado em Engenharia Eletrónica Industrial e Computadores

Plano de revitalização do centro histórico de Braga

Dissertação de mestrado em Políticas Comunitárias e Cooperação Territorial

Lazer e autorregulação emocional: contributos para o bem-estar e felicidade dos adolescentes

Dissertação de mestrado em Psicologia Aplicada

A utilização de materiais didáticos diversificados como estratégia de motivação

Relatório de estágio de mestrado em Ensino da Filosofia no Ensino Secundário

Síntese e caracterização de nanopartículas vetorizadas para células tumorais com possível aplicação na entrega controlada de fármacos

Dissertação de mestrado em Química Medicinal