10,312 research outputs found

    The Metaverse: Survey, Trends, Novel Pipeline Ecosystem & Future Directions

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    The Metaverse offers a second world beyond reality, where boundaries are non-existent, and possibilities are endless through engagement and immersive experiences using the virtual reality (VR) technology. Many disciplines can benefit from the advancement of the Metaverse when accurately developed, including the fields of technology, gaming, education, art, and culture. Nevertheless, developing the Metaverse environment to its full potential is an ambiguous task that needs proper guidance and directions. Existing surveys on the Metaverse focus only on a specific aspect and discipline of the Metaverse and lack a holistic view of the entire process. To this end, a more holistic, multi-disciplinary, in-depth, and academic and industry-oriented review is required to provide a thorough study of the Metaverse development pipeline. To address these issues, we present in this survey a novel multi-layered pipeline ecosystem composed of (1) the Metaverse computing, networking, communications and hardware infrastructure, (2) environment digitization, and (3) user interactions. For every layer, we discuss the components that detail the steps of its development. Also, for each of these components, we examine the impact of a set of enabling technologies and empowering domains (e.g., Artificial Intelligence, Security & Privacy, Blockchain, Business, Ethics, and Social) on its advancement. In addition, we explain the importance of these technologies to support decentralization, interoperability, user experiences, interactions, and monetization. Our presented study highlights the existing challenges for each component, followed by research directions and potential solutions. To the best of our knowledge, this survey is the most comprehensive and allows users, scholars, and entrepreneurs to get an in-depth understanding of the Metaverse ecosystem to find their opportunities and potentials for contribution

    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

    Deep Learning for Scene Flow Estimation on Point Clouds: A Survey and Prospective Trends

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    Aiming at obtaining structural information and 3D motion of dynamic scenes, scene flow estimation has been an interest of research in computer vision and computer graphics for a long time. It is also a fundamental task for various applications such as autonomous driving. Compared to previous methods that utilize image representations, many recent researches build upon the power of deep analysis and focus on point clouds representation to conduct 3D flow estimation. This paper comprehensively reviews the pioneering literature in scene flow estimation based on point clouds. Meanwhile, it delves into detail in learning paradigms and presents insightful comparisons between the state-of-the-art methods using deep learning for scene flow estimation. Furthermore, this paper investigates various higher-level scene understanding tasks, including object tracking, motion segmentation, etc. and concludes with an overview of foreseeable research trends for scene flow estimation

    Machine Learning Research Trends in Africa: A 30 Years Overview with Bibliometric Analysis Review

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    In this paper, a critical bibliometric analysis study is conducted, coupled with an extensive literature survey on recent developments and associated applications in machine learning research with a perspective on Africa. The presented bibliometric analysis study consists of 2761 machine learning-related documents, of which 98% were articles with at least 482 citations published in 903 journals during the past 30 years. Furthermore, the collated documents were retrieved from the Science Citation Index EXPANDED, comprising research publications from 54 African countries between 1993 and 2021. The bibliometric study shows the visualization of the current landscape and future trends in machine learning research and its application to facilitate future collaborative research and knowledge exchange among authors from different research institutions scattered across the African continent

    Développement d’un système intelligent de reconnaissance automatisée pour la caractérisation des états de surface de la chaussée en temps réel par une approche multicapteurs

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    Le rôle d’un service dédié à l’analyse de la météo routière est d’émettre des prévisions et des avertissements aux usagers quant à l’état de la chaussée, permettant ainsi d’anticiper les conditions de circulations dangereuses, notamment en période hivernale. Il est donc important de définir l’état de chaussée en tout temps. L’objectif de ce projet est donc de développer un système de détection multicapteurs automatisée pour la caractérisation en temps réel des états de surface de la chaussée (neige, glace, humide, sec). Ce mémoire se focalise donc sur le développement d’une méthode de fusion de données images et sons par apprentissage profond basée sur la théorie de Dempster-Shafer. Les mesures directes pour l’acquisition des données qui ont servi à l’entrainement du modèle de fusion ont été effectuées à l’aide de deux capteurs à faible coût disponibles dans le commerce. Le premier capteur est une caméra pour enregistrer des vidéos de la surface de la route. Le second capteur est un microphone pour enregistrer le bruit de l’interaction pneu-chaussée qui caractérise chaque état de surface. La finalité de ce système est de pouvoir fonctionner sur un nano-ordinateur pour l’acquisition, le traitement et la diffusion de l’information en temps réel afin d’avertir les services d’entretien routier ainsi que les usagers de la route. De façon précise, le système se présente comme suit :1) une architecture d’apprentissage profond classifiant chaque état de surface à partir des images issues de la vidéo sous forme de probabilités ; 2) une architecture d’apprentissage profond classifiant chaque état de surface à partir du son sous forme de probabilités ; 3) les probabilités issues de chaque architecture ont été ensuite introduites dans le modèle de fusion pour obtenir la décision finale. Afin que le système soit léger et moins coûteux, il a été développé à partir d’architectures alliant légèreté et précision à savoir Squeeznet pour les images et M5 pour le son. Lors de la validation, le système a démontré une bonne performance pour la détection des états surface avec notamment 87,9 % pour la glace noire et 97 % pour la neige fondante

    Augmented classification for electrical coil winding defects

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    A green revolution has accelerated over the recent decades with a look to replace existing transportation power solutions through the adoption of greener electrical alternatives. In parallel the digitisation of manufacturing has enabled progress in the tracking and traceability of processes and improvements in fault detection and classification. This paper explores electrical machine manufacture and the challenges faced in identifying failures modes during this life cycle through the demonstration of state-of-the-art machine vision methods for the classification of electrical coil winding defects. We demonstrate how recent generative adversarial networks can be used to augment training of these models to further improve their accuracy for this challenging task. Our approach utilises pre-processing and dimensionality reduction to boost performance of the model from a standard convolutional neural network (CNN) leading to a significant increase in accuracy

    Terapia fotodinâmica na inativação de bacteriófagos com porfirina e potenciadoresem águas residuais

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    Pathogenic viruses are frequently introduced into marine and estuarine waters through the discharge of treated and untreated sewage, since current treatments are unable to provide virus-free wastewater (WW) effluents, affecting the receiving waters quality and, consequently, human health. The removal of harmful constituents by the conventional treatments comprises a combination of chemical, physical and biological methods. Usually, WW from urban areas is secondarily, rarely tertiary, treated. Although the secondary effluent contains high concentrations of microorganisms, the effect of water dilution makes it acceptable in terms of quality indicators. In tertiary treatment, chlorination is the most common method used to ensure microbiological safety in tertiarily treated effluents. However, its massive utilization, both in free and combined chlorine forms, may lead to the formation of chemical disinfection by-products though the reaction with organic matter present in the effluents, being those chemicals toxic to aquatic organisms, representing potential health hazards. Unfortunately, these conventional methods are limited and may not be adequate to reach the quality levels specified by the guidelines. Photodynamic therapy (PDT) with porphyrins may be a promising approach for the inactivation of pathogens as they are effective in inactivating microorganisms without the formation of potentially toxic products. Some studies have reported an enhancer effect on antimicrobial photodynamic therapy (aPDT) by the combined used of some photosensitizer (PS) with potassium iodide (KI) and hydrogen peroxide (H2O2). The main objective of this study was to evaluate the aPDT efficacy of a PS based on a low-cost formulation constituted by five cationic porphyrins (Form) and its potentiation effect by KI and H2O2 in the inactivation of a T4-like bacteriophage in WW. The experiments were done in phosphate buffered saline and in filtered and non-filtered contaminated wastewater. The aPDT assays in filtered WW (0.45 μm pore-size) were performed with different concentrations of Form (1.0 to 10 μM). In a second phase was evaluated the effect of KI (100 mM) in the photodynamic action of Form (1.0 to 10 μM). The results of these experiments demonstrated that Form is efficient in filtered WW treatment and that the efficacy of bacteriophage photoinactivation is correlated with the concentration of the used PS. When combined with KI, the Form is clearly less effective to inactivate the bacteriophage. To evaluate if the organic matter present in water influences the efficiency of PS, the WW was filtered using three different pore-sized membranes (0.45, 0.30 and 0.22 μm). The results demonstrated that the increase of organic matter promote a significant decrease in the efficiency of Form. In order to evaluate if the efficiency of aPDT to inactivate bacteriophages is maintained when the treatments are performed in non-filtrated WW, the effect of Form alone (10 μM) and combined with H2O2 (2, 5 and 9%) in non-filtered WW was evaluated. The Form alone proved to be an efficient PS to photoinactivate the bacteriophage in non-filtered WW, but the presence of H2O2 enhanced the photodynamic effect. The FORM can be an effective alternative to control viruses in WW, particularly if combined with H2O2.Os vírus patogénicos são frequentemente introduzidos nas águas marinhas e estuarinas através da descarga de esgoto tratado e não tratado, uma vez que os tratamentos atuais não inativam os vírus presentes nas águas residuais (WW), afetando a qualidade das águas recetoras e, consequentemente, a saúde humana. Nos tratamentos convencionais, a remoção de constituintes nocivos consiste no uso de métodos químicos, físicos e biológicos. Geralmente, a WW de áreas urbanas é tratada secundariamente e não terciariamente. Embora o efluente secundário contenha altas concentrações de microrganismos, o efeito da diluição na água torna-o aceitável em termos de indicadores de qualidade. A cloração é o método mais comum usado para garantir a segurança microbiológica em efluentes tratados terciariamente. No entanto, a sua utilização maciça, tanto na forma de cloro livre como combinada, pode levar à formação de subprodutos químicos como resultado da reação com a matéria orgânica presente nos efluentes, sendo esses produtos químicos tóxicos para os organismos aquáticos, apresentando riscos para a saúde. Os métodos convencionais são limitados e podem não ser adequados para manter os níveis de qualidade especificados nas diretrizes. As porfirinas quando usadas como fotossensibilizadores (PS) na terapia fotodinâmica (PDT) podem ser desinfetantes promissores para a inativação de microrganismos patógenicos, pois são eficazes na inativação de microrganismos sem formação de produtos tóxicos. Alguns estudos mostraram efeito potenciador de alguns PS usados em terapia fotodinâmica antimicrobiana (aPDT) quando estes são usados em combinação com iodeto de potássio (KI) e peróxido de hidrogénio (H2O2). O principal objetivo deste estudo foi avaliar a eficácia da aPDT de um PS baseado numa formulação de baixo custo constituída por cinco porfirinas catiónicas (Form) e o seu efeito potenciador por KI e H2O2 na inativação de um bacteriófago tipo T4. As experiências foram realizadas em solução salina tamponada com fosfato e em água residual contaminada filtrada e não filtrada. Os ensaios de aPDT em WW filtrada (tamanho do poro de 0,45 μm) foram realizados com diferentes concentrações de Form (1,0 a 10 μM). Numa segunda fase foi avaliado o efeito do KI (100 mM) na ação fotodinâmica da FORM (1,0 a 10 μM). Os resultados dessas experiências demonstraram que a Form é eficiente no tratamento de WW filtrada e que a eficácia da fotoinativação de bacteriófagos está correlacionada com a concentração do PS usado. Quando combinada com o KI, a Form é claramente menos eficaz na inativação do bacteriófago. Para avaliar se a matéria orgânica presente na água influencia a eficiência do PS, a WW foi filtrada usando três membranas com tamanho de poros diferentes (0,45, 0,30 e 0,22 μm). Os resultados mostraram que o aumento da matéria orgânica promove uma diminuição significativa na eficiência da Form. Para avaliar se a eficiência da aPDT para inativar bacteriófagos é mantida quando os tratamentos são realizados em WW não filtrada, o efeito da Form sozinha (10 μM) e combinado com H2O2 (2, 5 e 9%) em WW não filtrada foi avaliado. A Form por si só provou ser um PS eficiente para fotoinativar o bacteriófago em WW não filtrada, mas a presença de H2O2 aumentou significativamente o efeito fotodinâmico. A Form pode ser uma alternativa eficaz para controlar vírus na WW, principalmente se combinada com H2O2.This work was supported by funding FEDER through COMPETE – Programa Operacional Factores de Competitividade, and by National funding through Fundação para a Ciência e Tecnologia (FCT) and Marine Studies (CESAM).Mestrado em Biologia Molecular e Celula

    Annals [...].

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    Pedometrics: innovation in tropics; Legacy data: how turn it useful?; Advances in soil sensing; Pedometric guidelines to systematic soil surveys.Evento online. Coordenado por: Waldir de Carvalho Junior, Helena Saraiva Koenow Pinheiro, Ricardo Simão Diniz Dalmolin

    Physical phenomena controlling quiescent flame spread in porous wildland fuel beds

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    Despite well-developed solid surface flame spread theories, we still lack a coherent theory to describe flame spread through porous wildland fuel beds. This porosity results in additional complexity, reducing the thermal conductivity of the fuel bed, but allowing in-bed radiative and convective heat transfer to occur. While previous studies have explored the effect of fuel bed structure on the overall fire behaviour, there remains a need for further investigation of the effect of fuel structure on the underlying physical phenomena controlling flame spread. Through an extensive series of laboratory-based experiments, this thesis provides detailed, physics-based insights for quiescent flame spread through natural porous beds, across a range of structural conditions. Measurements are presented for fuel beds representative of natural field conditions within an area of the fire-prone New Jersey Pinelands National Reserve, which compliment a related series of field experiments conducted as part of a wider research project. Additional systematic investigation across a wider range of fuel conditions identified independent effects of fuel loading and bulk density on the spread rate, flame height and heat release rate. However, neither fuel loading nor bulk density alone provided adequate prediction of the resulting fire behaviour. Drawing on existing structural descriptors (for both natural and engineered fuel beds) an alternative parameter ασδ was proposed. This parameter (incorporating the fuel bed porosity (α), fuel element surface-to-volume ratio (σ), and the fuel bed height (δ)) was strongly correlated with the spread rate. One effect of the fuel bed structure is to influence the heat transfer mechanisms both above and within the porous fuel bed. Existing descriptions of radiation transport through porous fuel beds are often predicated on the assumption of an isotropic fuel bed. However, given their preferential angle of inclination, the pine needle beds in this study may not exhibit isotropic behaviour. Regardless, for the structural conditions investigated, horizontal heat transfer through the fuel bed was identified as the dominant heating mechanism within this quiescent flame spread scenario. However, the significance of heat transfer contributions from the above-bed flame generally increased with increasing ασδ value of the fuel bed. Using direct measurements of the heat flux magnitude and effective heating distance, close agreement was observed between experimentally observed spread rates and a simple thermal model considering only radiative heat transfer through the fuel bed, particularly at lower values of ασδ. Over-predictions occurred at higher ασδ values, or where other heat transfer terms were incorporated, which may highlight the need to include additional heat loss terms. A significant effect of fuel structure on the primary flow regimes, both within and above these porous fuel beds, was also observed, with important implications for the heat transfer and oxygen supply within the fuel bed. Independent effects of fuel loading and bulk density on both the buoyant and buoyancy-driven entrainment flow were observed, with a complex feedback cycle occurring between Heat Release Rate (HRR) and combustion behaviour. Generally, increases in fuel loading resulted in increased HRR, and therefore increased buoyant flow velocity, along with an increase in the velocity of flow entrained towards the combustion region. The complex effects of fuel structure in both the flaming and smouldering combustion phases may necessitate modifications to other common modelling approaches. The widely used Rothermel model under-predicted spread rate for higher bulk density and lower ασδ fuel beds. As previously suggested, an over-sensitivity to fuel bed height was observed, with experimental comparison indicating an under-prediction of reaction intensity at lower fuel heights. These findings have important implications particularly given the continuing widespread use of the Rothermel model, which continues to underpin elements of the BehavePlus fire modelling system and the US National Fire Danger Rating System. The physical insights, and modelling approaches, developed for this low-intensity, quiescent flame spread scenario, are applicable to common prescribed fire activities. It is hoped that this work (alongside complimentary laboratory and field experiments conducted by various authors as part of a wider multi-agency project (SERDP-RC2641)) will contribute to the emerging field of prescribed fire science, and help to address the pressing need for further development of fire prediction and modelling tools

    Socio-endocrinology revisited: New tools to tackle old questions

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    Animals’ social environments impact their health and survival, but the proximate links between sociality and fitness are still not fully understood. In this thesis, I develop and apply new approaches to address an outstanding question within this sociality-fitness link: does grooming (a widely studied, positive social interaction) directly affect glucocorticoid concentrations (GCs; a group of steroid hormones indicating physiological stress) in a wild primate? To date, negative, long-term correlations between grooming and GCs have been found, but the logistical difficulties of studying proximate mechanisms in the wild leave knowledge gaps regarding the short-term, causal mechanisms that underpin this relationship. New technologies, such as collar-mounted tri-axial accelerometers, can provide the continuous behavioural data required to match grooming to non-invasive GC measures (Chapter 1). Using Chacma baboons (Papio ursinus) living on the Cape Peninsula, South Africa as a model system, I identify giving and receiving grooming using tri-axial accelerometers and supervised machine learning methods, with high overall accuracy (~80%) (Chapter 2). I then test what socio-ecological variables predict variation in faecal and urinary GCs (fGCs and uGCs) (Chapter 3). Shorter and rainy days are associated with higher fGCs and uGCs, respectively, suggesting that environmental conditions may impose stressors in the form of temporal bottlenecks. Indeed, I find that short days and days with more rain-hours are associated with reduced giving grooming (Chapter 4), and that this reduction is characterised by fewer and shorter grooming bouts. Finally, I test whether grooming predicts GCs, and find that while there is a long-term negative correlation between grooming and GCs, grooming in the short-term, in particular giving grooming, is associated with higher fGCs and uGCs (Chapter 5). I end with a discussion on how the new tools I applied have enabled me to advance our understanding of sociality and stress in primate social systems (Chapter 6)
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