Suchergebnisse

Doutoramento em Informática ; Internet users consume online targeted advertising based on information collected about them and voluntarily share personal information in social networks. Sensor information and data from smart-phones is collected and used by applications, sometimes in unclear ways. As it happens today with smartphones, in the near future sensors will be shipped in all types of connected devices, enabling ubiquitous information gathering from the physical environment, enabling the vision of Ambient Intelligence. The value of gathered data, if not obvious, can be harnessed through data mining techniques and put to use by enabling personalized and tailored services as well as business intelligence practices, fueling the digital economy. However, the ever-expanding information gathering and use undermines the privacy conceptions of the past. Natural social practices of managing privacy in daily relations are overridden by socially-awkward communication tools, service providers struggle with security issues resulting in harmful data leaks, governments use mass surveillance techniques, the incentives of the digital economy threaten consumer privacy, and the advancement of consumergrade data-gathering technology enables new inter-personal abuses. A wide range of fields attempts to address technology-related privacy problems, however they vary immensely in terms of assumptions, scope and approach. Privacy of future use cases is typically handled vertically, instead of building upon previous work that can be re-contextualized, while current privacy problems are typically addressed per type in a more focused way. Because significant effort was required to make sense of the relations and structure of privacy-related work, this thesis attempts to transmit a structured view of it. It is multi-disciplinary - from cryptography to economics, including distributed systems and information theory - and addresses privacy issues of different natures. As existing work is framed and discussed, the contributions to the ...

Dissertação de Mestrado Integrado em Engenharia Civil apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra. ; As inundações afectam milhões de pessoas e causam incontáveis prejuízos económicos e socias todos os anos, perfazendo mais de metade do número de desastres naturais em todo o Mundo (WMO, 2009). As inundações urbanas e suas metodologias de previsão, prevenção e mitigação são um assunto cada vez mais preocupante para a sociedade de hoje, devido ao aumento de casos de condições hidrológicas extremas, à cada vez maior urbanização do ambiente, e à elevada concentração de consumos de água e habitantes em centros urbanos. Nos últimos anos, esta combinação de um aumento contínuo de urbanização de espaços e eventos de precipitação extrema tem mostrado que os sistemas de drenagem nem sempre conseguem responder adequadamente ao aumento de caudal resultante destes fenómenos(Lima et al, 2013), levando a uma subida do nível de risco de inundação. Consequentemente, esta situação leva à necessidade de se criarem medidas para contrariar este problema grave na drenagem urbana: a União Europeia publicou em Outubro de 2007 a Directiva 2007/60/CE, na qual são realçadas as razões que levam a este aumento de probabilidade de ocorrência de inundações e as suas consequências sob a população e ambiente. Esta Directiva recomenda também a elaboração de mapas de risco de inundação por parte dos Estados-Membros. O objectivo deste trabalho é elaborar mapas de risco de inundação usando modelos de drenagem dual 1D2D no software Inforworks ICM, e quantificar o risco com uma metodologia quantitativa. A metodologia será aplicada a um caso de estudo numa bacia urbana de Coimbra. O impacto das inundações é demonstrado em mapas de risco de inundação baseados em curvas altura-prejuízos e altura-velocidade, através da análise dos resultados no software ArcGIS. ; Floods affect millions of people and cause uncountable economic and social losses every year, making up more than half of the natural disasters in the World (WMO, 2009). Urban floods and their prevision, prevention and mitigation methodologies are increasingly worrying topic for today's society, due to the raise of extreme hydrological condition cases (Furumai and Matsuura, 2006), the ever-increasing urbanization of the environment, and the high concentration of inhabitants in urban centres. In the last years, this combination of a continuous increase of urbanization of spaces and extreme rainfall events have shown that drainage systems do not always respond appropriately to the resulting increase of flow (Lima et al, 2013), leading to an intensification of flood risk. Consequently, this situation caused the need to create measures to undermine this serious problem in urban drainage: in October 2007, the European Union published the 2007/60/CE Directive, in which the reasons that lead to this increase of likelihood of floods were highlighted, as well as its consequences over the population and environment. The Directive also recommends the elaboration of flood hazard and flood risk maps by all the Member-States. The objective of this dissertation is to use a dual drainage 1D/2D model on the software Infoworks ICM to create flood risk maps, and to assess the risk with a quantitative methodology. The methodology will be applied to a study case in the Zona Central catchment in Coimbra. The impact of the floods is displayed as flood risk maps based on depth-damage and depth-velocity curves by analysing the results in the software ArcGIS.

UIDB/05021/2020 UIDP/05021/2020 ; This study investigates to what extent specific features of news articles about election campaigns impact reader engagement and civility in news comments. Using content analysis of articles (N = 830) and comments (N = 29,421) published during the 2015 Portuguese Legislative elections, we test the impact of negative coverage, issue coverage and game coverage (politics as a game) on the number of comments that an article receives and the level of civility thereof. Additionally, we explore how affective polarisation of a commenter may moderate the effects on incivility. Findings show that negativity towards political actors in an article is tied to both an increase in the number of comments and their level of incivility. Game coverage only led to a significant increase in the number of comments, while actor-related positivity was also related to an increase in incivility. Issue coverage had neither positive nor negative effects. The results inform newsrooms and academics about the implications of different types of election reporting, while accounting for features of news articles that are typically not integrated in a single study. ; publishersversion ; published

O Programa Bolsa Família, considerado referência internacional entre os modelos de condicional cash transfer, surge durante o primeiro governo do Partido dos Trabalhadores como resultado da unificação de diversos programas de transferência de renda anteriores que buscavam, sobretudo, romper com o ciclo da pobreza. O presente artigo tem o objetivo de descrever, por meio de um panorama histórico, o processo de construção do programa com base em suas experiências pregressas. Para tanto, utiliza como principal estratégia metodológica, a análise qualiquantitativa, com foco nos principais programas e iniciativas implementadas entre 1991 e 2003. Durante os 18 anos em que permaneceu em atividade, identifica que o programa contribuiu, em conjunto com as diversas políticas sociais implementadas, na redução dos índices gerais de pobreza e no fortalecimento do pacto federativo brasileiro.

This study investigates to what extent specific features of news articles about election campaigns impact reader engagement and civility in news comments. Using content analysis of articles (N = 830) and comments (N = 29,421) published during the 2015 Portuguese Legislative elections, we test the impact of negative coverage, issue coverage and game coverage (politics as a game) on the number of comments that an article receives and the level of civility thereof. Additionally, we explore how affective polarisation of a commenter may moderate the effects on incivility. Findings show that negativity towards political actors in an article is tied to both an increase in the number of comments and their level of incivility. Game coverage only led to a significant increase in the number of comments, while actor-related positivity was also related to an increase in incivility. Issue coverage had neither positive nor negative effects. The results inform newsrooms and academics about the implications of different types of election reporting, while accounting for features of news articles that are typically not integrated in a single study. ; POCH Programa Operacional Capital Humano, participated by the European Social Fund and by national funds by the MCTES by an individual doctoral scholarship granted by Fundação para a Ciência e Tecnologia (SFRH/BD/103335/2014). Text revision funded by Fundação para a Ciência e Tecnologia through project UIDB/00736/2020

We acknowledge the use of MODIS imagery obtained from NASA's Land Processes Distributed Active Archive Center (LP DAAC), available free of charge. The authors would like to thank the anonymous reviewers for providing comments and suggestions that helped to improve the quality of the original manuscript. ; Wildfire disturbances can cause modifications in different dimensions of ecosystem functioning, i.e., the flows of matter and energy. There is an increasing need for methods to assess such changes, as functional approaches offer advantages over those focused solely on structural or compositional attributes. In this regard, remote sensing can support indicators for estimating a wide variety of effects of fire on ecosystem functioning, beyond burn severity assessment. These indicators can be described using intra-annual metrics of quantity, seasonality, and timing, called Ecosystem Functioning Attributes (EFAs). Here, we propose a satellite-based framework to evaluate the impacts, at short to medium term (i.e., from the year of fire to the second year after), of wildfires on four dimensions of ecosystem functioning: (i) primary productivity, (ii) vegetation water content, (iii) albedo, and (iv) sensible heat. We illustrated our approach by comparing inter-annual anomalies in satellite-based EFAs in the northwest of the Iberian Peninsula, from 2000 to 2018. Random Forest models were used to assess the ability of EFAs to discriminate burned vs. unburned areas and to rank the predictive importance of EFAs. Together with effect sizes, this ranking was used to select a parsimonious set of indicators for analyzing the main effects of wildfire disturbances on ecosystem functioning, for both the whole study area (i.e., regional scale), as well as for four selected burned patches with different environmental conditions (i.e., local scale). With both high accuracies (area under the receiver operating characteristic curve (AUC) > 0.98) and effect sizes (Cohen's |d| > 0.8), we found important effects on all four dimensions, especially on primary productivity and sensible heat, with the best performance for quantity metrics. Different spatiotemporal patterns of wildfire severity across the selected burned patches for different dimensions further highlighted the importance of considering the multi-dimensional effects of wildfire disturbances on key aspects of ecosystem functioning at different timeframes, which allowed us to diagnose both abrupt and lagged effects. Finally, we discuss the applicability as well as the potential advantages of the proposed approach for more comprehensive assessments of fire severity. ; Portuguese national funds through FCT-Foundation for Science and Technology, I.P., under the GreenRehab project PCIF/RPG/0077/2017 ; Junta de Andalucia P18-RT-1927 ; European Union Funds for Regional Development ; Project DETECTOR A-RNM-256-UGR18 ; European Commission ; Portuguese Foundation for Science and Technology European Commission ; Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) European Commission ; European Social Fund, within the 2014-2020 EU Strategic Framework, through FCT SFRH/BD/99469/2014 ; Individual Scientific Employment Stimulus Program (2017), through FCT CEECIND/02331/2017

Global environmental changes are rapidly affecting species' distributions and habitat suitability worldwide, requiring a continuous update of biodiversity status to support effective decisions on conservation policy and management. In this regard, satellite-derived Ecosystem Functional Attributes (EFAs) offer a more integrative and quicker evaluation of ecosystem responses to environmental drivers and changes than climate and structural or compositional landscape attributes. Thus, EFAs may hold advantages as predictors in Species Distribution Models (SDMs) and for implementing multi-scale species monitoring programs. Here we describe a modelling framework to assess the predictive ability of EFAs as Essential Biodiversity Variables (EBVs) against traditional datasets (climate, land-cover) at several scales. We test the framework with a multi-scale assessment of habitat suitability for two plant species of conservation concern, both protected under the EU Habitats Directive, differing in terms of life history, range and distribution pattern (Iris boissieri and Taxus baccata). We fitted four sets of SDMs for the two test species, calibrated with: interpolated climate variables; landscape variables; EFAs; and a combination of climate and landscape variables. EFAbased models performed very well at the several scales (AUCmedian from 0.881±0.072 to 0.983±0.125), and similarly to traditional climate-based models, individually or in combination with land-cover predictors (AUCmedian from 0.882±0.059 to 0.995±0.083). Moreover, EFAbased models identified additional suitable areas and provided valuable information on functional features of habitat suitability for both test species (narrowly vs. widely distributed), for both coarse and fine scales. Our results suggest a relatively small scale-dependence of the predictive ability of satellite-derived EFAs, supporting their use as meaningful EBVs in SDMs from regional and broader scales to more local and finer scales. Since the evaluation of species' conservation status and habitat quality should as far as possible be performed based on scalable indicators linking to meaningful processes, our framework may guide conservation managers in decision-making related to biodiversity monitoring and reporting schemes. ; This research was developed as part of the ECOPOTENTIAL project financed by European Union's Horizon 2020 research and innovation program under grant agreement No. 641762. SAC, DAS and JPH received funding from the ECOPOTENTIAL project. JG was supported by FCT (Portuguese Science Foundation) through PhD grant SFRH/BD/90112/2012. DAS received funding from Ministerio de Educación, Cultura y Deporte, JC2015-00316 grant, and Ministerio de Ciencia e Innovación, CGL2014-61610-EXP project.