Historic and potential technology transition paths of grid battery storage: Co-evolution of energy grid, electric mobility and batteries

Scarcity of fuels, changes in environmental policy and in society increased the interest in generating electric energy from renewable energy sources (RES) for a sustainable energy supply in the future. The main problem of RES as solar and wind energy, which represent a main pillar of this transition, is that they cannot supply constant power output. This results inter alia in an increased demand of backup technologies as batteries to assure electricity system safety. The diffusion of energy storage technologies is highly dependent on the energy system and transport transition pathways which might lead to a replacement or reconfiguration of embedded socio-technical practices and regimes (by creating new standards or dominant designs, changing regulations, infrastructure and user patterns). The success of this technology is dependent on hardly predictable future technical advances, actor preferences, development of competing technologies and designs, diverging interests of actors, future cost efficiencies, environmental performance, the evolution of market demand and design and evolution of our society.

Medium access control design for distributed opportunistic radio networks

Existing wireless networks are characterized by a fixed spectrum assignment policy. However, the scarcity of available spectrum and its inefficient usage demands for a new communication paradigm to exploit the existing spectrum opportunistically. Future Cognitive Radio (CR) devices should be able to sense unoccupied spectrum and will allow the deployment of real opportunistic networks. Still, traditional Physical (PHY) and Medium Access Control (MAC) protocols are not suitable for this new type of networks because they are optimized to operate over fixed assigned frequency bands. Therefore, novel PHY-MAC cross-layer protocols should be developed to cope with the specific features of opportunistic networks. This thesis is mainly focused on the design and evaluation of MAC protocols for Decentralized Cognitive Radio Networks (DCRNs). It starts with a characterization of the spectrum sensing framework based on the Energy-Based Sensing (EBS) technique considering multiple scenarios. Then, guided by the sensing results obtained by the aforementioned technique, we present two novel decentralized CR MAC schemes: the first one designed to operate in single-channel scenarios and the second one to be used in multichannel scenarios. Analytical models for the network goodput, packet service time and individual transmission probability are derived and used to compute the performance of both protocols. Simulation results assess the accuracy of the analytical models as well as the benefits of the proposed CR MAC schemes.

The financial leverage of large Portuguese Firms in the European context

The Financial Leverage of Large Portuguese Firms in the European Context This paper studies the leverage, cost of debt servicing ability and structure of debt maturity of large Portuguese firms, over the pre-crisis (2006-2009) and post-crisis (2010-2013) periods through a comparative analysis with other European peers. We document that large Portuguese firms have been reducing their leverage since the end of 2009. We find that this decrease in leverage is not a consequence higher Equity levels but rather a result of asset’s downsizing. We also document that Portuguese firms are still more leveraged than their European peers, even though this difference has decreased over time. High corporate debt levels are transversal across industries.

The weilburg painting showing the lisbon entry of 1619 in its historical and pictorial context

This article deals with the splendid panoramic painting depicting the Joyeuse Entrée of King Philipp III (Filipe II de Portugal) in Lisbon in 1619 which the author discovered at Weilburg castle in Germany. The author places the painting in its historical and pictorial context by comparing it to the written reports of the entry and comparable 16th and 17th century views of Lisbon. Apparently, the painting is based on a strictly planned choreography that largely follows the previous entry of Philipp II, and is identical in the painted, engraved and written descriptions of the event published between 1619 and 1622.

How servant leadership is perceiver by leaders and followers in a Portuguese organizational context

Servant leadership theory has been the subject of great academic discussion, namely in what concerns reaching a consensus for its definition. As many frameworks have been designed in order to define the servant leader’s characteristics, we based ourselves in van Dierendonck’s review and synthesis on servant leadership (2011) to assess how it is perceived in a Portuguese organizational context. After performing several interviews in a private health care organization, we conclude that the perception of servant leadership is generally positive and that its characteristics seem to be in line with academic literature. However, some issues arose such as a seemingly lack of relevance given to authenticity and humility, the latter being a unique attribute of servant leadership. Also, we found a discrepancy between hierarchical levels’ perception of servant leadership characteristics as well as questioning if an over emphasis on service can diminish the servant leader’s impact on organizational performance.

Critical incident study on forgiveness in the organizational context

Forgiveness has been subject of interest, mainly in the psychology fields of study. Relatively to the organizational context, this topic has been somehow put aside and settled as something that is purely an intra-individual phenomenon which organizations cannot force, or even stimulate. As conflicts are common within organizations and being often difficult to overcome, eyes have turned into the role forgiveness might take in this scenario. Despite forgiveness being accepted as an intrapersonal decision and a result of predisposition as it is a result of education and culture. This study, as some already done, refuses to accept forgiveness as an unchangeable behavior that cannot be manipulated or induced by managers or by organizational context. Therefore, offering a set of incidents as well as their classification, that have been identified by individuals performing different types organizational roles in different organization which is believed as being a genuine way of delivering to the reader a set of actions and behaviors that if taken, may incentivize or inhibit forgiveness.

A importância da comunicação estratégica na alteração de comportamentos na sociedade : o caso Sociedade Ponto Verde

A comunicação estratégica poderá ser entendida como a comunicação alinhada com a estratégia global de uma organização para alcançar o seu posicionamento estratégico. Ou seja, para alcançar o sucesso, uma organização precisa de ter uma comunicação consistente com a sua identidade e, ao mesmo tempo, adequada ao seu público-alvo e ao tipo de sector onde se insere. Só desta forma consegue conquistar a confiança e fidelidade dos consumidores, essenciais para o alcance dos objectivos. Em relação à alteração comportamentos, é essencial que as empresas costruam uma estratégia de comunicação coerente e consistente, adaptando as mensagens e os públicos-alvo escolhidos. Neste âmbito da alteração de comportamentos, estudou-se neste trabalho a Sociedade Ponto Verde (SPV), uma associação portuguesa sem fins lucrativos, que actua no âmbito da gestão e reciclagem de resíduos de embalagens. Procurou estudar-se a evolução da sua comunicação ao longo dos anos e a forma como adaptou as suas mensagens, de forma a conseguir incutir na sociedade portuguesa a importância do comportamento de reciclagem de resíduos. Neste estudo, procedeu-se a uma análise individualizada de cada uma das campanhas de comunicação da SPV e, posteriormente, aplicou-se um inquérito por questionário, para verificar a eficácia das mesmas campanhas perante o público-alvo. A metodologia utilizada neste trabalho consistiu na distribuição de um inquérito por questionário online, que permitiu recolher uma amostra probabilística por conveniência. Em seguida, recolhidos e tratados os dados referentes às 482 respostas recebidas, utilizou-se o programa SPSS (Stastitical Package for the Social Sciences) para analisar, tratar e discutir os resultados obtidos. Estes resultados demonstraram que, de facto, não houve uma grande percentagem de inquiridos que se lembram das campanhas da SPV. Os resultados são positivos e não desmentem a qualidade e coerência das mensagens, mas a verdade é que a percentagem de indivíduos que não se lembra de algumas campanhas chega a ser elevada (em especial nas campanhas iniciais da organização, quando existia falta de uma estratégia coerente). Justifica-se este facto, em parte, pelo excesso de informação e estímulos a que as pessoas estão sujeitas, pelo que a informação que retêm não fica para sempre, acabando por dar lugar a outras informações. Os indivíduos são inconscientemente selectivos com a informação que processam e guardam, pois não seria possível guardar toda a informação que lhes é transmitida. No que diz respeito à comunicação estratégica que visa alterar uma atitude e, posteriormente, um comportamento, conclui-se que, no geral, o comportamento das pessoas inquiridas aparenta ter sido influenciado pela comunicação da SPV, caso contrário, as respostas afirmativas quanto à reciclagem e de concordância com algumas das afirmações teriam sido inferiores. Ou seja, mesmo reconhecendo o carácter um pouco enviesado da amostra (não deverá ser considerada representativa da população portuguesa), é possível dizer que a estratégia de comunicação da SPV (em especial a partir de 2005) foi eficiente. Palavras-

Distributed solar micro generation

Taking into account the fact that the sun’s radiation is estimated to be enough to cover 10.000 times the world’s total energy needs (BRAKMANN & ARINGHOFF, 2003), it is difficult to understand how solar photovoltaic systems (PV) are still such a small part of the energy source matrix across the globe. Though there is an ongoing debate as to whether energy consumption leads to economic growth or whether it is the other way around, the two variables appear correlated and it is clear that ensuring the availability of energy to match a country’s growth targets is one of the prime concerns for any government. The topic of centralized vs distributed electricity generation is also approached, especially in what regards the latter fit to developing countries needs, namely the lack of investment capabilities and infrastructure, scattered population, and other factors. Finally, Brazil’s case is reviewed, showing that the current cost of electricity from the grid versus the cost from PV solutions still places an investment of this nature with 9 to 16 years to reach breakeven (from a 25 year panel lifespan), which is too high compared to the required 4 years for most Brazilians. Still, recently passed legislation opened the door, even if unknowingly, to the development of co-owned solar farms, which could reduce the implementation costs by as much as 20% and hence reduce the number of years to breakeven by 3 years.

Context costs and comparative advantages in the telecommunications sector in Portugal and China

This Work Project aims to discuss the Context Costs and Comparative Advantages of the Telecommunications sector both in Portugal and China. The work was built mostly on primary research by interviews with relevant people (business persons, University Professors and Agencies directors), and by economic data publicly available. A list of context costs and comparative advantages was drawn for each country and possible resolutions suggestions were made in the end. The context costs depend heavily on the economic situation of the countries and it should be taken into account when assessing the degree of magnitude of each cost of context. The competitive advantages of each country were drawn in comparison with one another. Some key results stand out: firstly, Portugal’s costs of context depend mainly on governmental decisions, uncertainties and instability and China’s cost of context depend primarily on cultural norms, mainly the Guanxi; second, the telecommunications sector shares most of its context costs and advantages with other sectors; third, China as an economic power could use the telecommunications sector as a way to further develop and boost its economy.

How to improve urban mobility in Lisbon: intermodality and information and ticketing systems

Urban mobility is one of the main challenges facing urban areas due to the growing population and to traffic congestion, resulting in environmental pressures. The pathway to urban sustainable mobility involves strengthening of intermodal mobility. The integrated use of different transport modes is getting more and more important and intermodality has been mentioned as a way for public transport compete with private cars. The aim of the current dissertation is to define a set of strategies to improve urban mobility in Lisbon and by consequence reduce the environmental impacts of transports. In order to do that several intermodal practices over Europe were analysed and the transport systems of Brussels and Lisbon were studied and compared, giving special attention to intermodal systems. In the case study was gathered data from both cities in the field, by using and observing the different transport modes, and two surveys were done to the cities users. As concluded by the study, Brussels and Lisbon present significant differences. In Brussels the measures to promote intermodality are evident, while in Lisbon a lot still needs to be done. It also made clear the necessity for improvements in Lisbon’s public transports to a more intermodal passenger transport system, through integration of different transport modes and better information and ticketing system. Some of the points requiring developments are: interchanges’ waiting areas; integration of bicycle in public transport; information about correspondences with other transport modes; real-time information to passengers pre-trip and on-trip, especially in buses and trams. After the identification of the best practices in Brussels and the weaknesses in Lisbon the possibility of applying some of the practices in Brussels to Lisbon was evaluated. Brussels demonstrated to be a good example of intermodality and for that reason some of the recommendations to improve intermodal mobility in Lisbon can follow the practices in place in Brussels.

Multifunctional converter to interface renewable energy sources and electric vehicles with the power grid in smart grids context

This paper proposes a multifunctional converter to interface renewable energy sources (e.g., solar photovoltaic panels) and electric vehicles (EVs) with the power grid in smart grids context. This multifunctional converter allows deliver energy from the solar photovoltaic panels to an EV or to the power grid, and exchange energy in bidirectional mode between the EV and the power grid. Using this multifunctional converter are not required multiple conversion stages, as occurs with the traditional solutions, where are necessary two power converters to integrate the solar photovoltaic system in the power grid and also two power converters to integrate an off-board EV battery charger in the power grid (dc-dc and dc-ac power converters in both cases). Taking into account that the energy provided (or delivered) from the power grid in each moment is function of the EV operation mode and also of the energy produced from the solar photovoltaic system, it is possible to define operation strategies and control algorithms in order to increase the energy efficiency of the global system and to improve the power quality of the electrical system. The proposed multifunctional converter allows the operation in four distinct cases: (a) Transfer of energy from the solar photovoltaic system to the power grid; (b) Transfer of energy from the solar photovoltaic system and from the EV to the power grid; (c) Transfer of energy from the solar photovoltaic system to the EV or to the power grid; (d) Transfer of energy between the EV and the power grid. Along the paper are described the system architecture and the control algorithms, and are also presented some computational simulation results for the four aforementioned cases. It is also presented a comparative analysis between the traditional and the proposed solution in terms of operation efficiency and estimated cost of implementation.

The economic assessment of health benefits of active transport

Purpose:This chapter addresses the economic assessment of health benefits of active transport and presents most recent valuation studies with an overview of progresses made towards the inclusion of health benefits in the cost-benefit analysis (CBA) of active transport. Methodology/approach: It is built upon the contracted study for the World Health Organization (WHO) on the economic appraisal of health benefits of walking and cycling investments at the city of Viana do Castelo, the former pilot study in Portugal for evaluating the health benefits of non-motorized transport using the WHO Health Economic Assessment Tool (HEAT). The relative risk values adopted in the HEAT for walking refer to adult population of the age group 20â 74 years and the assessment focus in on average physical activity/regular behaviour of groups of pedestrians and all-cause mortality health impacts. During the case study, it was developed and implemented a mobility survey which aimed to collect behavioural data before and after a street intervention in the historic centre. Findings: Most recent appraisal guidance of walking and cycling and health impact modelling studies reviewed confirm that further research is expected before a more comprehensive appraisal procedure can be adopted in Europe, able to integrate physical activity effects along with other health risks such as those related to road traffic injuries and exposure to air pollution. Social implications: The health benefits assessment of walking investments helped local decision-makers to progress towards sustainable mobility options in the city. Making the population aware of the potential health benefits of regular walking can encourage more people to uptake active transport as part of their daily activities. Originality/value: This study provides a useful review of the health benefits of active transport with a comprehensive analysis of valuation studies, presenting value-added information. It then reports a former assessment of the health effects of active transport in the Portuguese context (case study) using the state-of-the-art economic analysis tool (HEAT) of the World Health Organization which is believed to contribute to a paradigm shift in the transport policy and appraisal practice given the need of shaping future cities (and their citizens) for health through more investments in active transport.

Epidemic store for massive scale systems

The MAP-i doctoral program of the Universities of Minho, Aveiro and Porto

Ensino, aprendizagem e avaliação no Ensino Superior: Perspetivas e práticas

Tese de Doutoramento em Ciências da Educação - Especialidade de Desenvolvimento Curricular