514 research outputs found

    On price convergence in Eurozone

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    We investigate price level convergence with Germany in eleven countries belonging to the Eurozone between January 1970 and July 2011. Relying on smooth transition regression models, we show that the price convergence process is nonlinear, depending on the size of the price differential: for most countries, price convergence occurs only when price differentials with Germany exceed a certain threshold. Moreover, our findings put forward some heterogeneity across the Eurozone members in terms of price convergence speed, that can be explained by the evolution of price-competitiveness, rigidities in labor markets, but also by specialization patterns.price convergence, Eurozone, smooth transition regression models, half-life

    Is the European debt crisis a mere balance of payments crisis?

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    This paper is interested in linking formally external disequilibriums to the sovereign debt crisis the EMU is experiencing since 2009. Relying on the CHEER approach that connects the goods market to the capital market, we show that when a country belonging to a monetary union faces external disequilibrium relative to its main partner, the corresponding interest rate differential increases. Moreover, when these imbalances are persistent, it may trigger a balance of payments crisis. Our findings indicate that this phenomenon seems to be at play for the European countries under international assistance

    Is price dynamics homogeneous across Eurozone countries?

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    The aim of this paper is to investigate whether price dynamics is homogeneous across the Eurozone countries. Relying on monthly data over the January 1970-July 2011 period, we test for the absolute purchasing power parity (PPP) hypothesis through the implementation of second-generation panel unit root and cointegration tests. Our results show that price dynamics are heterogeneous depending on both the time period and the considered group of countries. More specifically, while PPP is validated for the core EMU countries, this hypothesis does not hold for Northern peripheral economies. Turning to the Southern countries, PPP is observed only before the launch of the euro.price convergence, Eurozone, panel unit root tests, half-life

    Virtual sensor networks: collaboration and resource sharing

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    This thesis contributes to the advancement of the Sensing as a Service (SeaaS), based on cloud infrastructures, through the development of models and algorithms that make an efficient use of both sensor and cloud resources while reducing the delay associated with the data flow between cloud and client sides, which results into a better quality of experience for users. The first models and algorithms developed are suitable for the case of mashups being managed at the client side, and then models and algorithms considering mashups managed at the cloud were developed. This requires solving multiple problems: i) clustering of compatible mashup elements; ii) allocation of devices to clusters, meaning that a device will serve multiple applications/mashups; iii) reduction of the amount of data flow between workplaces, and associated delay, which depends on clustering, device allocation and placement of workplaces. The developed strategies can be adopted by cloud service providers wishing to improve the performance of their clouds. Several steps towards an efficient Se-aaS business model were performed. A mathematical model was development to assess the impact (of resource allocations) on scalability, QoE and elasticity. Regarding the clustering of mashup elements, a first mathematical model was developed for the selection of the best pre-calculated clusters of mashup elements (virtual Things), and then a second model is proposed for the best virtual Things to be built (non pre-calculated clusters). Its evaluation is done through heuristic algorithms having such model as a basis. Such models and algorithms were first developed for the case of mashups managed at the client side, and after they were extended for the case of mashups being managed at the cloud. For the improvement of these last results, a mathematical programming optimization model was developed that allows optimal clustering and resource allocation solutions to be obtained. Although this is a computationally difficult approach, the added value of this process is that the problem is rigorously outlined, and such knowledge is used as a guide in the development of better a heuristic algorithm.Esta tese contribui para o avanço tecnológico do modelo de Sensing as a Service (Se-aaS), baseado em infraestrutura cloud, através do desenvolvimento de modelos e algoritmos que resolvem o problema da alocação eficiente de recursos, melhorando os métodos e técnicas atuais e reduzindo os tempos associados `a transferência dos dados entre a cloud e os clientes, com o objetivo de melhorar a qualidade da experiência dos seus utilizadores. Os primeiros modelos e algoritmos desenvolvidos são adequados para o caso em que as mashups são geridas pela aplicação cliente, e posteriormente foram desenvolvidos modelos e algoritmos para o caso em que as mashups são geridas pela cloud. Isto implica ter de resolver múltiplos problemas: i) Construção de clusters de elementos de mashup compatíveis; ii) Atribuição de dispositivos físicos aos clusters, acabando um dispositivo físico por servir m´ múltiplas aplicações/mashups; iii) Redução da quantidade de transferência de dados entre os diversos locais da cloud, e consequentes atrasos, o que dependente dos clusters construídos, dos dispositivos atribuídos aos clusters e dos locais da cloud escolhidos para realizar o processamento necessário. As diferentes estratégias podem ser adotadas por fornecedores de serviço cloud que queiram melhorar o desempenho dos seus serviços.(…

    Traces, high powers and one level density for families of curves over finite fields

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    Fado: vocal acoustic characterization

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    Trabalho apresentado no 20th World Congress of the International Federation of Oto-Rhino-Laryngological Societies, 1-5 junho 2013, Seul, Coreia do Su

    Social gaming: A systematic review

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    Digital games often constitute a shared activity where people can spend time together, communicate and socialize. Several commercial titles place social interaction at the center of their design. Prior works have investigated the social outcomes of gaming, and factors that impact the experience. Yet, we lack a comprehensive understanding of how social gaming has been approached and explored before. In this work, we present a systematic review covering 263 publications, gathered in February 2021, that study gaming experiences involving more than one person, with a focus on the social element that emerges among partakers (players and/or spectators). We contribute with a systematized understanding of (1) how the topic is being defined and approached, (2) what facets (mainly in terms of outcomes and determinants of the experience) are being acknowledged and (3) the methodologies leveraged to examine these. Our analysis, based on mixed deductive and inductive coding, reveals relevant gaps and tendencies, including (1) the emphasis in novel technologies and unconventional games, (2) the apparent negligence of player diversity, and (3) lower ecological validity associated with totally mediated evaluations and a lack of established constructs to assess social outcomes

    Plano de negócios: incubadora de investigação e desenvolvimento para a inovação de dispositivos médicos em Portugal - Região Autónoma dos Açores

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    Em Portugal verifica-se a inexistência de uma organização orientada para o desenvolvimento e inovação em Dispositivos Médicos (DMs), neste mercado em constante expansão no setor da saúde. Apresenta-se um projeto-piloto para a implementação de uma incubadora especializada em investigação e desenvolvimento para a inovação de DMs, que concentre serviços, potencie a geração das ideias e motive a capacidade de inovação dos empreendedores e "startups" nesta área. A incubadora proposta localizar-se-á em Portugal, na Região Autónoma dos Açores, tirando partido do seu enquadramento geográfico, económico e das iniciativas de desenvolvimento tecnológico promovidas na região, potenciadoras de sucesso para a implementação de uma incubadora de base nacional a internacionalizar. A AZORES MEDTECH nos diferentes cenários identificados - otimista, realista e pessimista - apresenta como fatores críticos comuns de sucesso e viabilidade a angariação de empresas locais e a captação e fidelização de empreendedores e "startups", que se prevêm de todo o mundo, durante as diversas fases de exploração. As prestações provenientes das empresas locais servirão para adquirir todo o capital fixo e fazer face às despesas resultantes da atividade. A execução deste projeto no cenário realista exigirá um custo inicial de cerca de 87 000 euros em 2018, gerando no primeiro ano de exploração proveitos de 151 280 euros, os quais ascenderão a 176 440 euros em 2021, com um Valor Atual Líquido (VAL) positivo de 110 210 euros. Para os restantes cenários delineados o projeto é rentável para os quatro anos em análise, apresentando um VAL positivo.In Portugal there is a lack of an organization dedicated to the development and innovation in Medical Devices (MDs), a market in constant expansion in the health setor. It is presented a pilot project for the implementation of an incubator specialized in research and development of innovation in MDs that concentrates services, promotes the generation of ideas and motivates the entrepreneurs and startups capacity for innovation in this field. The proposed incubator will be located in Portugal, in the Autonomous Region of the Azores, taking advantage of its geographic, economic environment and of the technological development initiatives promoted in the region, key for the successful implementation of a national-based incubator with internationalization intent. The AZORES MEDTECH in the different scenarios identified - optimistic, realistic and pessimistic - presents as common critical factors of success and viability the capture of local companies and fidelization of entrepreneurs and startups, expected from all over the world during the various phases of exploration. The instalments obtained from these companies will be used to acquire all the fixed capital and cover the activity expenses. The execution of this project in the realistic scenario will require an initial cost of around 87 000 euros in 2018, generating in the first year of operation revenue of 151 280 euros, which will increase to 176 440 euros in 2021, with a positive Net Present Value (NPV) of 110 210 euros. For the remaining outlined scenarios, the project is profitable for the four years under analysis, presenting a positive NPV
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