Radio frequency identification: o futuro da gestão de stocks na grande distribuição

Dissertação apresentada como requisito parcial para obtenção do grau de Mestre em Estatística e Gestão de Informação

ECG wave detector and delineation with wavelets

Proceedings of the International Conference on Computational Intelligence in Medicine Healthcare, CIMED 2005, Costa da Caparica, June 29 - July 1, 2005

Automated image tagging through tag propagation

Trabalho apresentado no âmbito do Mestrado em Engenharia Informática, como requisito parcial Para obtenção do grau de Mestre em Engenharia Informática

Selection of a co-operation agreement between EMOVE – Innovative Technologies and WavEC – Wave Energy Center

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Implementation of a cognitive radio access system

Dissertação apresentada para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores, pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

Spectrum sensing through software defined radio

Dissertação apresentada para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores, pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

On and off air: an ethnographic exploration of minority radio in Portugal

Taking a Media Anthropology’s approach to dynamics of mediated selfrepresentation in migratory contexts, this thesis starts by mapping radio initiatives produced by, for and/or with migrants in Portugal. To further explore dynamics of support of initial settlement in the country, community-making, cultural reproduction, and transnational connectivity - found both in the mapping stage and the minority media literature (e.g. Kosnick, 2007; Rigoni & Saitta, 2012; Silverstone & Georgiou, 2005) - a case study was selected: the station awarded with the first bilingual license in Portugal. The station in question caters largely to the British population presenting themselves as “expats” and residing in the Algarve. The ethnographic strategy to research it consisted of “following the radio” (Marcus, 1995) beyond the station and into the events and establishments it announces on air, so as to relate production and consumption realms. The leading research question asks how does locally produced radio play into “expats” processes of management of cultural identity – and what are the specificities of its role? Drawing on conceptualizations of lifestyle migration (Benson & O’Reilly, 2009), production of locality (Appadurai 1996) and the public sphere (Butsch, 2007; Calhoun & et al, 1992; Dahlgren, 2006), this thesis contributes to valuing radio as a productive gateway to research migrants’ construction of belonging, to inscribe a counterpoint in the field of minority media, and to debate conceptualizations of migratory categories and flows. Specifically, this thesis argues that the station fulfills similar roles to other minority radio initiatives but in ways that are specific to the population being catered to. Namely, unlike other minority stations, radio facilitates the process of transitioning between categories along on a continuum linking tourists and migrants. It also reflects and participates in strategies of reterritorialization that rest on functional and partial modes of incorporation. While contributing to sustain a translocality (Appadurai, 1996) it indexes and fosters a stance of connection that is symbolically and materially connected to the UK and other “neighborhoods” but is, simultaneously, oriented to engaging with the Algarve as “home”. Yet, besides reifying a British cultural identity, radio’s oral, repetitive and ephemeral discourse particularly trivializes the reproduction of an ambivalent stance of connection with place that is shared by other “expats”. This dynamic is related to migratory projects driven by social imaginaries fostered by international media that stimulate the search for idealized ways of living, which the radio associates with the Algarve. While recurrently localizing and validating the narrative projecting an idealized “good life”, radio amplifies dynamics among migrants that seem to reaffirm the migratory move as a good choice.

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.

A wave of change: Labor market and social security impacts of the EU refugee inflow

The recent massive inflow of refugees to the European Union (EU) raises a number of unanswered questions on the economic impact of this phenomenon. To examine these questions, we constructed an overlapping-generations model that describes the evolution of the skill premium and of the welfare benefit level in relevant European countries, in the aftermath of an inflow of asylum-seekers. In our simulation, relative wages of skilled workers increase between 8% and 11% in the period of the inflow; their subsequent time path is dependent on the initial skill premium. The entry of migrants creates a fiscal surplus of about 8%, which can finance higher welfare benefits in the subsequent periods. These effects are weaker in a scenario where refugees do not fully integrate into the labor market.

Damage propagation in composite Materials meso-mechanical models

Composite materials have a complex behavior, which is difficult to predict under different types of loads. In the course of this dissertation a methodology was developed to predict failure and damage propagation of composite material specimens. This methodology uses finite element numerical models created with Ansys and Matlab softwares. The methodology is able to perform an incremental-iterative analysis, which increases, gradually, the load applied to the specimen. Several structural failure phenomena are considered, such as fiber and/or matrix failure, delamination or shear plasticity. Failure criteria based on element stresses were implemented and a procedure to reduce the stiffness of the failed elements was prepared. The material used in this dissertation consist of a spread tow carbon fabric with a 0°/90° arrangement and the main numerical model analyzed is a 26-plies specimen under compression loads. Numerical results were compared with the results of specimens tested experimentally, whose mechanical properties are unknown, knowing only the geometry of the specimen. The material properties of the numerical model were adjusted in the course of this dissertation, in order to find the lowest difference between the numerical and experimental results with an error lower than 5% (it was performed the numerical model identification based on the experimental results).

Comportamentos das famílias portuguesas em épocas de calor e durante a onda de calor de Agosto de 2003

RESUMO - Este estudo teve como principal objectivo a caracterização das atitudes e da adopção de medidas de protecção em períodos de calor e em particular conhecer aquelas que efectivamente foram adoptadas durante a onda de calor de Agosto de 2003 (29 de Julho a 15 de Agosto). Foi realizado um inquérito por via postal, aplicando um questionário aos indivíduos de 18 e mais anos das unidades de alojamento (UA), que constituem a amostra ECOS (Em Casa Observamos Saúde) do Observatório Nacional de Saúde. Estudaram-se 769 indivíduos, o que correspondeu a 25,6% da totalidade dos indivíduos elegíveis nas UA. Uma vez que a amostra ECOS não é autoponderada, foram ponderados os resultados das unidades de alojamento pela variável do Instituto Nacional de Estatística (INE) «número de famílias clássicas» por região e pela «população residente segundo o nível de instrução» obtidas pelos censos de 2001. Os comportamentos referidos como adoptados em épocas de calor que apresentaram maiores percentagens foram «tomar duches ou banhos» (84,6%), «ingestão de líquidos» (79,6%), «uso de roupa leve, larga e clara» (73,2%) e «tomar refeições leves» (53,7%). Durante a onda de calor de 2003, a maior parte da população (92,5%) leu, ouviu ou viu informação sobre os cuidados a ter durante a onda de calor, tendo sido a televisão (95,2%), a rádio (56,3%) e os jornais (49,3%) os meios de comunicação social mais referidos. Cerca de metade da população (51,4%) informou alguém, fundamentalmente a família, sobre os cuidados a ter. Com efeito, durante esta onda de calor verificou-se um maior cuidado em relação a comportamentos mais prejudiciais em épocas de maior calor. Por um lado, a população portuguesa andou menos ao sol (49,4%), fez menos viagens de carro/transportes à hora do calor (39,8%), realizou menos actividades que exigiriam esforço físico (32,5%) e também houve alguma preocupação em beber menos bebidas alcoólicas (26,5%). Por outro lado, aumentaram os comportamentos que já são mais habituais durante o período de Verão, tais como abrir as janelas durante a noite (40,8%), tomar refeições leves (46,7%), tomar mais duches ou banhos (58,5%), o uso de roupas leves largas e claras (42,5%) e o uso de ventoinhas (37,8%). A alteração do comportamento andar ou estar ao sol sem restrições aumenta com o número de meios de comunicação onde se obteve informação. Abrir as janelas de casa durante a noite e tomar duches ou banhos apresentou uma associação com o número de meios de comunicação onde se obteve informação e com o número de pessoas que prestaram informação. Ingerir líquidos e usar roupa leve, larga e clara mostrou também uma dependência do número de meios de comunicação onde se obteve informação.