14,815 research outputs found

    Multilevel governance and control of the Covid-19 pandemic in the Democratic Republic of Congo: Learning from the four first waves

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    The COVID-19 pandemic continues to impose a heavy burden on people around the world. The Democratic Republic of the Congo (DRC) has also been affected. The objective of this study was to explore national policy responses to the COVID-19 pandemic in the DRC and drivers of the response, and to generate lessons for strengthening health systems’ resilience and public health capacity to respond to health security threats. This was a case study with data collected through a literature review and in-depth interviews with key informants. Data analysis was carried out manually using thematic content analysis translated into a logical and descriptive summary of the results. The management of the response to the COVID-19 pandemic reflected multilevel governance. It implied a centralized command and a decentralized implementation. The centralized command at the national level mostly involved state actors organized into ad hoc structures. The decentralized implementation involved state actors at the provincial and peripheral level including two other ad hoc structures. Non-state actors were involved at both levels

    A Design Science Research Approach to Smart and Collaborative Urban Supply Networks

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    Urban supply networks are facing increasing demands and challenges and thus constitute a relevant field for research and practical development. Supply chain management holds enormous potential and relevance for society and everyday life as the flow of goods and information are important economic functions. Being a heterogeneous field, the literature base of supply chain management research is difficult to manage and navigate. Disruptive digital technologies and the implementation of cross-network information analysis and sharing drive the need for new organisational and technological approaches. Practical issues are manifold and include mega trends such as digital transformation, urbanisation, and environmental awareness. A promising approach to solving these problems is the realisation of smart and collaborative supply networks. The growth of artificial intelligence applications in recent years has led to a wide range of applications in a variety of domains. However, the potential of artificial intelligence utilisation in supply chain management has not yet been fully exploited. Similarly, value creation increasingly takes place in networked value creation cycles that have become continuously more collaborative, complex, and dynamic as interactions in business processes involving information technologies have become more intense. Following a design science research approach this cumulative thesis comprises the development and discussion of four artefacts for the analysis and advancement of smart and collaborative urban supply networks. This thesis aims to highlight the potential of artificial intelligence-based supply networks, to advance data-driven inter-organisational collaboration, and to improve last mile supply network sustainability. Based on thorough machine learning and systematic literature reviews, reference and system dynamics modelling, simulation, and qualitative empirical research, the artefacts provide a valuable contribution to research and practice

    The stumbling block in ‘the race of our lives’: transition-critical materials, financial risks and the NGFS climate scenarios

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    Several ‘critical’ raw materials, including metals, minerals and Rare Earth Elements (REEs), play a central role in the low-carbon transition and are needed to expand the deployment of low-carbon technologies. The reliable and affordable supply of these resources is subject to supply-side risks and demand-induced pressures. This paper empirically estimates the material demand requirements for ‘Transition-Critical Materials’ (TCMs) implied under two NGFS Climate Scenarios, namely the ‘Net Zero by 2050’ and ‘Delayed Transition’ scenarios. We apply material intensity estimates to the underlying assumptions on the deployment of low-carbon technologies to determine the implied material demand between 2021 and 2040 for nine TCMs. We find several materials to be subject to significant demand-induced pressures under both scenarios. Subsequently, the paper examines the possible emergence of material bottlenecks for three materials, namely copper, lithium and nickel. The results indicate possible substantial mismatches between supply and demand, which would be further exacerbated if the transition is delayed rather than realised immediately. We discuss these findings in the context of different possible transmission channels through which these bottlenecks could affect financial and price stability, and propose avenues for future research

    Reinforcement Learning-based User-centric Handover Decision-making in 5G Vehicular Networks

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    The advancement of 5G technologies and Vehicular Networks open a new paradigm for Intelligent Transportation Systems (ITS) in safety and infotainment services in urban and highway scenarios. Connected vehicles are vital for enabling massive data sharing and supporting such services. Consequently, a stable connection is compulsory to transmit data across the network successfully. The new 5G technology introduces more bandwidth, stability, and reliability, but it faces a low communication range, suffering from more frequent handovers and connection drops. The shift from the base station-centric view to the user-centric view helps to cope with the smaller communication range and ultra-density of 5G networks. In this thesis, we propose a series of strategies to improve connection stability through efficient handover decision-making. First, a modified probabilistic approach, M-FiVH, aimed at reducing 5G handovers and enhancing network stability. Later, an adaptive learning approach employed Connectivity-oriented SARSA Reinforcement Learning (CO-SRL) for user-centric Virtual Cell (VC) management to enable efficient handover (HO) decisions. Following that, a user-centric Factor-distinct SARSA Reinforcement Learning (FD-SRL) approach combines time series data-oriented LSTM and adaptive SRL for VC and HO management by considering both historical and real-time data. The random direction of vehicular movement, high mobility, network load, uncertain road traffic situation, and signal strength from cellular transmission towers vary from time to time and cannot always be predicted. Our proposed approaches maintain stable connections by reducing the number of HOs by selecting the appropriate size of VCs and HO management. A series of improvements demonstrated through realistic simulations showed that M-FiVH, CO-SRL, and FD-SRL were successful in reducing the number of HOs and the average cumulative HO time. We provide an analysis and comparison of several approaches and demonstrate our proposed approaches perform better in terms of network connectivity

    DT-RRNS: Routing Protocol Design for Secure and Reliable Distributed Smart Sensors Communication Systems

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    A smart city has a complex hierarchical communication system with various components. It must meet the requirements of fast connection, reliability, and security without data compromise. Internet of Things technology is widely used to provide connectivity and control solutions for smart sensors and other devices using heterogeneous networking technologies. In this paper, we propose a routing solution for Wireless Sensor Networks (WSN) and Mobile Ad hoc NETworks (MANET) with increasing speed, reliability, and sufficient security. Many routing protocols have been proposed for WSNs and MANETs. We combine the Secret Sharing Schemes (SSS) and Redundant Residual Number Systems (RRNS) to provide an efficient mechanism for a Distributed dynamic heterogeneous network Transmission (DT) with new security and reliability routing protocol (DT-RRNS). We analyze the concept of data transmission based on RRNS that divides data into smaller encoded shares and transmits them in parallel, protecting them from attacks on routes by adaptive multipath secured transmission and providing self-correcting properties that improve the reliability and fault tolerance of the entire system

    Smart Handover with Predicted User Behavior using Convolutional Neural Networks for WiGig Systems

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    WiGig networks and 60 GHz frequency communications have a lot of potential for commercial and personal use. They can offer extremely high transmission rates but at the cost of low range and penetration. Due to these issues, WiGig systems are unstable and need to rely on frequent handovers to maintain high-quality connections. However, this solution is problematic as it forces users into bad connections and downtime before they are switched to a better access point. In this work, we use Machine Learning to identify patterns in user behaviors and predict user actions. This prediction is used to do proactive handovers, switching users to access points with better future transmission rates and a more stable environment based on the future state of the user. Results show that not only the proposal is effective at predicting channel data, but the use of such predictions improves system performance and avoids unnecessary handovers.Comment: Submitted to IEEE Networ

    Biological impacts of marine heatwaves

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    Climatic extremes are becoming increasingly common against a background trend of global warming. In the oceans, marine heatwaves (MHWs)—discrete periods of anomalously warm water—have intensified and become more frequent over the past century, impacting the integrity of marine ecosystems globally. We review and synthesize current understanding of MHW impacts at the individual, population, and community levels. We then examine how these impacts affect broader ecosystem services and discuss the current state of research on biological impacts of MHWs. Finally, we explore current and emergent approaches to predicting the occurrence and impacts of future events, along with adaptation and management approaches. With further increases in intensity and frequency projected for coming decades, MHWs are emerging as pervasive stressors to marine ecosystems globally. A deeper mechanistic understanding of their biological impacts is needed to better predict and adapt to increased MHW activity in the Anthropocene

    Pattern reconfigurable dielectric resonator antenna using capacitor loading for internet of things applications

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    This research study presents a cube dielectric resonator antenna (DRA) with four different radiation patterns for internet of things (IoT) applications. The various radiation patterns are determined by the grounded capacitor loading to reduce interference. The DRA is constructed of ceramic material with a dielectric constant of 30 and is fed via a coaxial probe located in the antenna’s center. Capacitors are used to load the four parasitic microstrip feed lines. Each pattern of radiation is adjustable by adjusting the capacitors loading on the feed line. The proposed antenna works at 3.5 GHz with -10 narrow impedance bandwidth of 74 MHz

    Anuário científico da Escola Superior de Tecnologia da Saúde de Lisboa - 2021

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    É com grande prazer que apresentamos a mais recente edição (a 11.ª) do Anuário Científico da Escola Superior de Tecnologia da Saúde de Lisboa. Como instituição de ensino superior, temos o compromisso de promover e incentivar a pesquisa científica em todas as áreas do conhecimento que contemplam a nossa missão. Esta publicação tem como objetivo divulgar toda a produção científica desenvolvida pelos Professores, Investigadores, Estudantes e Pessoal não Docente da ESTeSL durante 2021. Este Anuário é, assim, o reflexo do trabalho árduo e dedicado da nossa comunidade, que se empenhou na produção de conteúdo científico de elevada qualidade e partilhada com a Sociedade na forma de livros, capítulos de livros, artigos publicados em revistas nacionais e internacionais, resumos de comunicações orais e pósteres, bem como resultado dos trabalhos de 1º e 2º ciclo. Com isto, o conteúdo desta publicação abrange uma ampla variedade de tópicos, desde temas mais fundamentais até estudos de aplicação prática em contextos específicos de Saúde, refletindo desta forma a pluralidade e diversidade de áreas que definem, e tornam única, a ESTeSL. Acreditamos que a investigação e pesquisa científica é um eixo fundamental para o desenvolvimento da sociedade e é por isso que incentivamos os nossos estudantes a envolverem-se em atividades de pesquisa e prática baseada na evidência desde o início dos seus estudos na ESTeSL. Esta publicação é um exemplo do sucesso desses esforços, sendo a maior de sempre, o que faz com que estejamos muito orgulhosos em partilhar os resultados e descobertas dos nossos investigadores com a comunidade científica e o público em geral. Esperamos que este Anuário inspire e motive outros estudantes, profissionais de saúde, professores e outros colaboradores a continuarem a explorar novas ideias e contribuir para o avanço da ciência e da tecnologia no corpo de conhecimento próprio das áreas que compõe a ESTeSL. Agradecemos a todos os envolvidos na produção deste anuário e desejamos uma leitura inspiradora e agradável.info:eu-repo/semantics/publishedVersio

    L’Asie du Sud-Est 2023 : bilan, enjeux et perspectives

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    Chaque année, l’Institut de recherche sur l’Asie du Sud-Est contemporaine (IRASEC), basé à Bangkok, mobilise une vingtaine de chercheurs et d’experts pour mieux comprendre l’actualité régionale de ce carrefour économique, culturel et religieux, au cœur de l’Indo-Pacifique. Cette collection permet de suivre au fil des ans l’évolution des grands enjeux contemporains de cette région continentale et archipélagique de plus de 680 millions d’habitants, et d’en comprendre les dynamiques d’intégration régionale et de connectivités avec le reste du monde. L’Asie du Sud-Est 2023 propose une analyse synthétique et détaillée des principaux événements politiques et diplomatiques, ainsi que des évolutions économiques, sociales et environnementales de l’année 2022 dans chacun des onze pays de la région. Ce décryptage est complété pour chaque pays par un focus sur deux personnalités de l’année et une actualité marquante en image. L’ouvrage propose également cinq dossiers thématiques qui abordent des sujets traités à l’échelle régionale sud-est asiatique : les ressorts institutionnels de l’approche de santé intégrée One Health, le vieillissement de la population et sa prise en compte par les politiques publiques, les câbles sous-marins au cœur de la connectivité sud-est asiatique, l’aménagement du bassin du Mékong et ses multiples acteurs, et les enjeux politiques et linguistiques des langues transnationales. Des outils pratiques sont également disponibles : une fiche et une chronologie par pays et un cahier des principaux indicateurs démographiques, sociaux, économiques et environnementaux
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