Portugal: o caminho entre o real e o virtual

A revolução tecnológica que se verificou a partir da década de 1980 e o fenómeno da globalização geraram alterações profundas nas sociedades contemporâneas. Desde então, praticamente todos os aspetos do seu quotidiano passaram a depender dos sistemas computorizados, que numa primeira fase estavam ligados em pequenas redes e começaram depois a ficar interligados através da Internet. Esta evolução para a Era da Informação mudou drasticamente o modo como se lida com os riscos. A virtualização do mundo real fez com que surgissem novas ameaças à segurança com origem no domínio cibernético, bem como por seu intermédio. Entretanto, o mundo Pós-Guerra Fria também alterou profundamente o sistema internacional e também viu surgir um conjunto de novos atores, estatais e não estatais, que vieram provocar instabilidade ao sistema, fosse por vontade própria ou como consequência dos acontecimentos. Atualmente, as ameaças à segurança são múltiplas e de natureza variada, sendo o ciberespaço um domínio utilizado pelos vários atores no sentido de desestabilizar a ordem instalada, como por exemplo através do ativismo político, mas também como meio para infringir danos. As capacidades cibernéticas passaram também a ser consideradas como mais uma opção para atuar em conflitos, principalmente pelas grandes potências. Neste contexto, o presente trabalho tem como objetivo analisar a abordagem em Portugal a esta nova realidade, em que a maioria, se não todas, das suas infraestruturas críticas dependem do bom funcionamento das ligações em rede, e em que estas são utilizadas por mais de metade da população portuguesa de forma regular.

Wiki: Plataforma Colaborativa para uma Comunicade de Prática Virtual Lusófona

Com este trabalho procura-se encontrar uma solução através de um modelo para a gestão do conhecimento numa organização internacional com base em tecnologia web 2.0 que sirva de plataforma colaborativa na criação e disseminação de conhecimento para uma comunidade de prática virtual, mas também que sirva de repositório da memória organizacional. Pretende-se, igualmente, demonstrar um novo modelo de organização social e económico, no qual se assume uma orientação para as pessoas enquanto elemento de um sistema social mais amplo, globalizado e disperso, ligado pelas tecnologias de participação e colaboração através do acesso à internet, que encontra na utilização destas ferramentas um interface para participação que vai desde a cidadania, à produção intelectual, criação de conhecimento e ao negócio, neste caso relacionado com uma prática, a gestão de recursos humanos nos países lusófonos. No decurso do projeto, estabeleceram-se contactos e reuniões de trabalho na sede da comunidade interessada, a CRHLP – Confederação de Profissionais de Recursos Humanos de Língua Portuguesa, cujos resultados constam do presente relatório para explicação das várias fases do projeto. O projeto culmina com uma proposta de um site colaborativo com base num Wiki (site Wiki), tecnologia de colaboração online, a Wiki-CRHLP – Plataforma de colaboração para a partilha do conhecimento de uma rede de prática virtual (rede profissional internacional).

The Visual and Virtual in Contemporary European Learning Contexts

Special issue of Anthropology in Action originated from the Working Images Conference, a joint meeting of TAN and VAN EASA networks

ENERGÍA EÓLICA Y PAISAJES PROTEGIDOS: CONTROVERSIAS EN EL PARQUE NATURAL DE MONTESINHO

As one of the case studies developed under the international project “Eoliennes et paysage” we could follow the controversial issue of wind power and protected areas in the Montesinho Natural Park, Northeast Portugal, where the local populations demand the setting up of a wind farm in unproductive communal lands, aspiring to benefi t economically from it, while the preservationist claims against wind power within the protected area are sensed by them as an external and illegitimate interference in the communitarian management of a local heritage. Although wind power installation in Montesinho mountains is yet only a virtual possibility (facing hard administrative and technical barriers), this case study contributed to shed light into the kind of negotiations that are being promoted at local and regional levels, and how the present banning of wind power in the region due to conservation restrictions is reactivating ancient antagonisms.

Wind Power in the Portuguese Landscape: Global Concerns and Local Costs

Wind turbines and solar panels are becoming second nature in Portugal, as its occurrence in the country becomes ubiquitous. Somehow, one could argue that renewable energy in Portugal is in the process of ‘naturalisation’ as part of a new – mechanised, but environmentally benign – landscape. Portuguese Institute for the Conservation of Nature and Biodiversity (ICNB) has shown an ambiguous stance on this issue, defending global concerns towards renewable energy, while at the same time attempting to engage locals in the preservation of extensive ‘classified areas’. In the course of this research, we tried to focus on these incongruities and to analyse how they are impacting local communities during the process of wind power installation.

Desenvolvimento de uma interface de visualização de conectividade cerebral usando realidade virtual e controlo por gestos

A presente dissertação foi desenvolvida em colaboração com o Instituto de Biofísica e Engenharia Biomédica(IBEB/FCUL)

Is low worker mobility evidence for monopsony power?

Major in Competition and Regulation

Simplified wind turbine models for wind energy integration into power systems

This paper analyses the boundaries of simplified wind turbine models used to represent the behavior of wind turbines in order to conduct power system stability studies. Based on experimental measurements, the response of recent simplified (also known as generic) wind turbine models that are currently being developed by the International Standard IEC 61400-27 is compared to complex detailed models elaborated by wind turbine manufacturers. This International Standard, whose Technical Committee was convened in October 2009, is focused on defining generic simulation models for both wind turbines (Part 1) and wind farms (Part 2). The results of this work provide an improved understanding of the usability of generic models for conducting power system simulations.

Uncertain Spaces: Virtual Configurations in Contemporary Art and Museums

Contém artigos apresentados na International Conference “Uncertain Spaces: Virtual Configurations in Contemporary Art and Museums”, na Fundação Calouste Gulbenkian (Lisboa), 31 Outubro - 1 de Novembro de 2014) de: Helena Barranha e Susana S. Martins - Introduction: Art, Museums and Uncertainty (pp.1-12); Alexandra Bounia e Eleni Myrivili - Beyond the ‘Virtual’: Intangible Museographies and Collaborative Museum Experiences (pp.15-32); Annet Dekker - Curating in Progress. Moving Between Objects and Processes (pp.33-54); Giselle Beiguelman - Corrupted Memories. The aesthetics of Digital Ruins and the Museum of the Unfinished (pp.55-82); Andrew Vaas Brooks - The Planetary Datalinks (pp.85-110); Sören Meschede - Curators’ Network: Creating a Promotional Database for Contemporary Visual Arts (pp.11-130); Stefanie Kogler - Divergent Histories and Digital Archives of Latin American and Latino Art in the United States – Old Problems in New Digital Formats (pp.131-156); Luise Reitstätter e Florian Bettel - Right to the City! Right to the Museum!(pp.159-182); Roberto Terracciano - On Geo-poetic systems: virtual interventions inside and outside the museum space (pp.183-210); e, Catarina Carneiro de Sousa e Luís Eustáquio - Art Practice in Collaborative Virtual Environments (pp.211-240).

Experimental and modeling studies on reverse electrodialysis for sustainable power generation

A potentially renewable and sustainable source of energy is the chemical energy associated with solvation of salts. Mixing of two aqueous streams with different saline concentrations is spontaneous and releases energy. The global theoretically obtainable power from salinity gradient energy due to World’s rivers discharge into the oceans has been estimated to be within the range of 1.4-2.6 TW. Reverse electrodialysis (RED) is one of the emerging, membrane-based, technologies for harvesting the salinity gradient energy. A common RED stack is composed by alternately-arranged cation- and anion-exchange membranes, stacked between two electrodes. The compartments between the membranes are alternately fed with concentrated (e.g., sea water) and dilute (e.g., river water) saline solutions. Migration of the respective counter-ions through the membranes leads to ionic current between the electrodes, where an appropriate redox pair converts the chemical salinity gradient energy into electrical energy. Given the importance of the need for new sources of energy for power generation, the present study aims at better understanding and solving current challenges, associated with the RED stack design, fluid dynamics, ionic mass transfer and long-term RED stack performance with natural saline solutions as feedwaters. Chronopotentiometry was used to determinate diffusion boundary layer (DBL) thickness from diffusion relaxation data and the flow entrance effects on mass transfer were found to avail a power generation increase in RED stacks. Increasing the linear flow velocity also leads to a decrease of DBL thickness but on the cost of a higher pressure drop. Pressure drop inside RED stacks was successfully simulated by the developed mathematical model, in which contribution of several pressure drops, that until now have not been considered, was included. The effect of each pressure drop on the RED stack performance was identified and rationalized and guidelines for planning and/or optimization of RED stacks were derived. The design of new profiled membranes, with a chevron corrugation structure, was proposed using computational fluid dynamics (CFD) modeling. The performance of the suggested corrugation geometry was compared with the already existing ones, as well as with the use of conductive and non-conductive spacers. According to the estimations, use of chevron structures grants the highest net power density values, at the best compromise between the mass transfer coefficient and the pressure drop values. Finally, long-term experiments with natural waters were performed, during which fouling was experienced. For the first time, 2D fluorescence spectroscopy was used to monitor RED stack performance, with a dedicated focus on following fouling on ion-exchange membrane surfaces. To extract relevant information from fluorescence spectra, parallel factor analysis (PARAFAC) was performed. Moreover, the information obtained was then used to predict net power density, stack electric resistance and pressure drop by multivariate statistical models based on projection to latent structures (PLS) modeling. The use in such models of 2D fluorescence data, containing hidden, but extractable by PARAFAC, information about fouling on membrane surfaces, considerably improved the models fitting to the experimental data.

Enel green power: Equity research

UNL - NSBE

Analysis and implementation of a multi-ratio switched capacitor DC-DC converter for a supercapacitor power supply

An energy harvesting system requires an energy storing device to store the energy retrieved from the surrounding environment. This can either be a rechargeable battery or a supercapcitor. Due to the limited lifetime of rechargeable batteries, they need to be periodically replaced. Therefore, a supercapacitor, which has ideally a limitless number of charge/discharge cycles can be used to store the energy; however, a voltage regulator is required to obtain a constant output voltage as the supercapacitor discharges. This can be implemented by a Switched-Capacitor DC-DC converter which allows a complete integration in CMOS technology, although it requires several topologies in order to obtain a high efficiency. This thesis presents the complete analysis of four different topologies in order to determine expressions that allow to design and determine the optimum input voltage ranges for each topology. To better understand the parasitic effects, the implementation of the capacitors and the non-ideal effect of the switches, in 130 nm technology, were carefully studied. With these two analysis a multi-ratio SC DC-DC converter was designed with an output power of 2 mW, maximum efficiency of 77%, and a maximum output ripple, in the steady state, of 23 mV; for an input voltage swing of 2.3 V to 0.85 V. This proposed converter has four operation states that perform the conversion ratios of 1/2, 2/3, 1/1 and 3/2 and its clock frequency is automatically adjusted to produce a stable output voltage of 1 V. These features are implemented through two distinct controller circuits that use asynchronous time machines (ASM) to dynamically adjust the clock frequency and to select the active state of the converter. All the theoretical expressions as well as the behaviour of the whole system was verified using electrical simulations.