Chern-Simons dilaton black holes in 2+1 dimensions

We construct rotating magnetic solutions to the three-dimensional Einstein-Maxwell-Chern-Simons-dilaton theory with a Liouville potential. These include a class of black hole solutions which generalize the warped AdS black holes. The regular black holes belong to two disjoint sectors. The first sector includes black holes which have a positive mass and are co-rotating, while the black holes of the second sector have a negative mass and are counter-rotating. We also show that a particular, non-black hole, subfamily of our three-dimensional solutions may be uplifted to new regular non-asymptotically flat solutions of five-dimensional Einstein-Maxwell-Chern-Simons theory.Comment: 26 pages, 3 figures, published versio

Automatic Temperature Extraction from Arresters’ Thermal Images with Artificial Intelligence

Os para-raios são fundamentais para garantir a confiabilidade, a economia e a segurança dos sistemas elétricos. Entretanto, a degradação que ocorre naturalmente ao longo do tempo representa um problema que leva a um desafio ainda em aberto, no qual vários estudos científicos propuseram e exploraram técnicas inovadoras de diagnóstico. Um novo método de diagnóstico manual está sendo empregado atualmente em subestações elétricas. O método emprega uma lógica anotada paraconsistente de dois valores, usando medições de temperatura por termografia infravermelha e dados de corrente de fuga resistiva como entrada para uma avaliação precisa da condição do para-raios. Tal método baseia-se em campanhas de coleta para obter imagens térmicas de para-raios de alta tensão em operação, exigindo posteriormente a extração manual dos dados de temperatura máxima e média e suas diferenças (delta) ao longo do eixo principal de cada para-raios por meio de um software de câmera digital. Nesse contexto, este estudo tem como objetivo aprimorar e automatizar o diagnóstico de para-raios por meio do cálculo automático da temperatura delta, introduzindo um novo método, cuja abordagem é baseada em Inteligência Artificial Deep Learning. O método proposto neste estudo emprega um modelo de Rede Neural Convolucional de Região de Máscara (Mask R-CNN) para segmentação dos para-raios a partir da imagem térmica, seguido de um algoritmo para extração de dados de temperatura dos para-raios, que são usados para diagnóstico de degradação. O processo de segmentação de para-raios com Mask R-CNN, em imagens térmicas, mostrou se viável, com uma precisão média de 83,85%. A análise comparativa da precisão média entre o método manual (original) e o método proposto (automatizado), a partir de 195 imagens térmicas processadas, revelou um Erro Percentual Absoluto Médio (MAPE) de 11,48% na temperatura delta, que é usada na análise da degradação do para-raios. Esse resultado demonstra que o método proposto neste estudo é viável e permite automatizar a inspeção de para-raios. Investigações futuras consistem em refinar o processo de segmentação por meio do ajuste fino dos hiperparâmetros e do uso da técnica de validação cruzad

Computational Modeling of Propeller Noise: NASA SR-7A propeller

The aerospace industry has been concerned with propeller noise levels for years. This interest is two-fold: government regulation and comfort in cabin. This report attempts to create a simulation mechanism needed to evaluate the far-field noise generation levels. However, in order to do that, the tandem cylinder case was evaluated first as a validation step before the SR-7A propeller case was performed. Both cases use STAR-CCM+, a commercial software, to perform the simulations

Chern-Simons dilaton black holes in 2+1 dimensions

International audienceWe construct rotating magnetic solutions to the three-dimensionalEinstein-Maxwell-Chern-Simons-dilaton theory with a Liouvillepotential. These include a class of black hole solutions whichgeneralize the warped AdS black holes. The regular black holesbelong to two disjoint sectors. The first sector includes blackholes which have a positive mass and are co-rotating, while theblack holes of the second sector have a negative mass and arecounter-rotating. We also show that a particular, non-black hole,subfamily of our three-dimensional solutions may be uplifted to newregular non-asymptotically flat solutions of five-dimensionalEinstein-Maxwell-Chern-Simons theory

Estudo das Propriedades Físico-Químicas do CaCu3-xSrxTi4O12 (0 < X < 3,00), Modificados com Óxido de Grafeno e Óxido de Grafeno Reduzido, como Material de Eletrodo para Supercapacitores

Neste trabalho focamos na preparação e investigação de sistemas de CaCu3-xSrxTi4O12 (0 x 3,00), puros e modificados com óxido de grafeno (OG) e óxido de grafeno reduzido (OGr), direcionados à aplicação como eletrodos em supercapacitores. O material matriz é um composto multifuncional com aplicações em dispositivos de armazenamento de energia devido à sua alta constante dielétrica. A difração de raios X, a microscopia eletrônica de varredura e a voltametria cíclica foram usados para examinarmos tanto as propriedades eletroquímicas quanto estruturais desses materiais. Os resultados indicam que a adição de 6% de OGr ao CCTO resulta em um aumento significativo da capacitância específica em todas as velocidades de varredura, o que implica que o OGr melhora a capacidade de armazenamento de carga do CCTO. Entretanto, a adição de OG aparentemente diminui a capacitância específica em relação ao CCTO puro. Observamos também que o CCTO 0.15 com 6% de OGr exibe os valores mais altos de capacitância específica. Por outro lado, a adição de OG parece não contribuir positivamente para as propriedades eletroquímicas do CCTO 0.15, resultando em uma redução da capacitância específica. No caso do CCTO 0.30, encontramos uma ligeira melhoria na capacitância específica com a adição de 6% de OG. Por fim, em relação ao SCTO, a adição de OG ou OGr gera valores de capacitância específica semelhantes ou levemente superiores ao SCTO puro, o que indica que a influência desses materiais nas propriedades eletroquímicas do SCTO pode ser limitada. Esses resultados iniciais oferecem insights valiosos sobre o potencial de uso do CCTO e suas variações como materiais de eletrodos para supercapacitores, abrindo caminho para futuras investigações nesse sentido. Ainda assim, entendemos que há espaço para otimizar a síntese e a resposta elétrica desses sistemas, apresentando oportunidades adicionais para melhorar o desempenho dos supercapacitores baseados em CCTO

Chiffrement authentifié sur FPGAs de la partie reconfigurable à la partie static

Communication systems need to access, store, manipulate, or communicate sensitive information. Therefore, cryptographic primitives such as hash functions and block ciphers are deployed to provide encryption and authentication. Recently, techniques have been invented to combine encryption and authentication into a single algorithm which is called Authenticated Encryption (AE). Combining these two security services in hardware produces better performance compared to two separated algorithms since authentication and encryption can share a part of the computation. Because of combining the programmability with the performance ofcustom hardware, FPGAs become more common as an implementation target for such algorithms. The first part of this thesis is devoted to efficient and high-speed FPGA-based architectures of AE algorithms, AES-GCM and AEGIS-128, in order to be used in the reconfigurable part of FPGAs to support security services of communication systems. Our focus on the state of the art leads to the introduction of high-speed architectures for slow changing keys applications like Virtual Private Networks (VPNs). Furthermore, we present an efficient method for implementing the GF(2¹²⁸) multiplier, which is responsible for the authentication task in AES-GCM, to support high-speed applications. Additionally, an efficient AEGIS-128is also implemented using only five AES rounds. Our hardware implementations were evaluated using Virtex-5 and Virtex-4 FPGAs. The performance of the presented architectures (Thr./Slices) outperforms the previously reported ones.The second part of the thesis presents techniques for low cost solutions in order to secure the reconfiguration of FPGAs. We present different ranges of low cost implementations of AES-GCM, AES-CCM, and AEGIS-128, which are used in the static part of the FPGA in order to decrypt and authenticate the FPGA bitstream. Presented ASIC architectures were evaluated using 90 and 65 nm technologies and they present better performance compared to the previous work.Les systèmes de communication ont besoin d'accéder, stocker, manipuler, ou de communiquer des informations sensibles. Par conséquent, les primitives cryptographiques tels que les fonctions de hachage et le chiffrement par blocs sont déployés pour fournir le cryptage et l'authentification. Récemment, des techniques ont été inventés pour combiner cryptage et d'authentification en un seul algorithme qui est appelé authentifiés Encryption (AE). La combinaison de ces deux services de sécurité dans le matériel de meilleures performances par rapport aux deux algorithmes séparés puisque l'authentification et le cryptage peuvent partager une partie du calcul. En raison de la combinaison de la programmation de l'exécution de matériel personnalisé, FPGA deviennent plus communs comme cible d'une mise en œuvre de ces algorithmes. La première partie de cette thèse est consacrée aux architectures d'algorithmes AE, AES-GCM et AEGIS-128 à base de FPGA efficaces et à grande vitesse, afin d'être utilisé dans la partie reconfigurable FPGA pour soutenir les services de sécurité des systèmes de communication. Notre focalisation sur l'état de l'art conduit à la mise en place d'architectures à haute vitesse pour les applications lentes touches changeantes comme les réseaux privés virtuels (VPN). En outre, nous présentons un procédé efficace pour mettre en œuvre le GF(2¹²⁸) multiplicateur, qui est responsable de la tâche d'authentification en AES-GCM, pour supporter les applications à grande vitesse. En outre, un système efficace AEGIS-128 est également mis en œuvre en utilisant seulement cinq tours AES. Nos réalisations matérielles ont été évaluées à l'aide Virtex-5 et Virtex-4 FPGA. La performance des architectures présentées (Thr. / Parts) surpasse ceux signalés précédemment. La deuxième partie de la thèse présente des techniques pour des solutions à faible coût afin de garantir la reconfiguration du FPGA. Nous présentons différentes gammes de mises en œuvre à faible coût de AES-GCM, AES-CCM, et AEGIS-128, qui sont utilisés dans la partie statique du FPGA afin de décrypter et authentifier le bitstream FPGA. Architectures ASIC présentées ont été évaluées à l'aide de 90 et 65 technologies nm et présentent de meilleures performances par rapport aux travaux antérieurs

COVID-19 disclosure : a novel measurement and annual report uncertainty

This paper provides a unique COVID-19 disclosure measurement and investigates the association between the level of COVID-19 disclosure and uncertainty within annual reports for UK FTSE-All share non-financial firms. We used automated textual analysis to score the sampled annual reports. The results show that the level of COVID-19 disclosure varies from industry to industry. Furthermore, there is a positive relationship between COVID-19 disclosure and uncertainty in annual reports. Firms with larger boards exhibit more significant uncertainty in annual reports with COVID-19 disclosure. However, the significance of uncertainty in annual reports with COVID-19 disclosure remains at the same level with different board independence percentages. The unique findings of this paper are extremely relevant to governments, shareholders, policymakers, suppliers, and creditors.Peer reviewe

On the (im)possibility of a supersymmetric extension of NGT

We investigate the possibility of constructing a locally supersymmetric extension of NGT (Nonsymmetric Gravitation Theory), based on the graded extension of the Poincare group. In the framework of the simple model that we propose, we end up with a no-go result, namely the impossibility of cancelling some linear contribution in the gravitino field. This drawback seems to seriously undermine the construction of a supergravity based on NGT.Comment: 17 pages, Latex,two references added, minor changes for clarity, v3: E-mail changed, v4 : Ref(9) correcte

COVID-19 disclosure : a novel measurement and annual report uncertainty

This paper provides a unique COVID-19 disclosure measurement and investigates the association between the level of COVID-19 disclosure and uncertainty within annual reports for UK FTSE-All share non-financial firms. We used automated textual analysis to score the sampled annual reports. The results show that the level of COVID-19 disclosure varies from industry to industry. Furthermore, there is a positive relationship between COVID-19 disclosure and uncertainty in annual reports. Firms with larger boards exhibit more significant uncertainty in annual reports with COVID-19 disclosure. However, the significance of uncertainty in annual reports with COVID-19 disclosure remains at the same level with different board independence percentages. The unique findings of this paper are extremely relevant to governments, shareholders, policymakers, suppliers, and creditors

Niveau De Contamination Du Poivron (Capsicum L., 1753) Par Les Pesticides

The study was done on two species of peppers capsicumannuum and capsicum fructescens. It concerned ninety samples of these two species, collected during three countrysides in two localities of Côte d’Ivoire (Bouake and Dabou). These samples were handled by means of a liquid-phase leading chromatograph SHIMADZU with the aim of determining the residues of pesticides. The observed results revealed a contamination of both species : capsicum annuum and capsicum fructescens, indeed, six residues of pesticides (chlorothalonil, chlorpyrifos, carbendazim, maneb, dimethoate and lambdacyaholothrine) were detected in these two species distributed in four families of pesticides (organochlorines, organophosphates, carbamates and pyrethrinoïds). The analysis showed that pyrethrinoïdes with respective proportions of 76,17% and 75,95% in capsicum annuum and capsicum fructescens were the most important ; followed organophosphate with respective proportions of 10,93% and 20,04% in capsicum annuum and capsicum fructescens.The study also showed that the concentrations of residues of pesticides detected in the edible part (pericarp ) peppers are appreciably equal those found in the part inedible(pulp). However, the residues of pesticides detected in peppers of both localities have all average concentrations lower than the standards established by the Codex Alimentarius