Roaming service for electric vehicle charging using blockchain-based digital identity

We present a suitable approach to address the electric vehicle charging roaming problem (e-roaming). Blockchain technologies are applied to support the identity management process of users charging their vehicles and to record energy transactions securely. At the same time, off-chain cloud-based storage is used to record the transaction details. A user wallet settled on a mobile application stores user verified credentials; a backend application in the vehicle charging station validates the user credentials to authorize the energy transaction. The current model can be applied to similar contexts where the user may be required to keep several credentials from different providers to authenticate digital transactions.info:eu-repo/semantics/publishedVersio

Afilamento e forma do tronco de árvores de Eucalyptus grandis e Eucalyptus saligna e suas variações com a adubação.

Este trabalho analisa possíveis alterações no afilamento médio e fator de forma de árvores de Eucalyptus saligna e Eucalyptus grandis pelo efeito de aplicação de fertilizantes no momento de plantio e parcelada durante a rotação. Os experimentos de adubação, com estas espécies foram implantados na região dos cerrados, nos municípios de Brotas e Altinópolis, Estado de São Paulo. Os tratamentos foram selecionados devido à elevada resposta à adubação obtida ao final da rotação. Os resultados obtidos para afilamento médio e fator de forma, de parcelas e árvores adubadas e não adubadas, possibilitaram as seguintes conclusões: a) O afilamento médio das parcelas diminuiu do quarto para o sexto ano e posteriormente aumentou para o oitavo ano. Aparentemente, estas variações deveram-se a uma redução na taxa de crescimento em altura e um aumento na taxa de crescimento em diâmetro, durante o mesmo período. b) A adubação melhorou levemente a forma das árvores do Eucalyptus grandis, e este efeito está indiretamente relacionado com as diferentes quantidades de fertilizantes devido ao seu efeito no crescimento em altura das árvores. c) As variações no afilamento médio das árvores podem ser atribuídas às alterações nos padrões de crescimento em altura e diâmetro. Variáveis diferentes que alteram a conicidade das árvores, devem ser primeiramente analisadas em relação à sua influência no crescimento em altura e diâmetro, antes de serem consideradas como fatores isolados. d) Nenhuma alteração foi verificada, na relação entre o diâmetro à altura do peito e na metade da altura da árvore, que pudesse ser atribuída às doses ou métodos de aplicação de fertilizantes. e) Não foi possível obter-se uma regressão precisa para estimar fatores de forma baseada nas variáveis estudadas neste trabalho

Mudanças, mitos e incertezas da produção de feijão: 1985 a 2010.

O presente trabalho tem por objetivo apresentar análises de movimentos e quantidade ofertada por estado e safra, considerando apenas a produção do feijão comum.CONAFE

Acervo do herbário IAN. 1. Meliaceae Ventenat.

bitstream/item/65644/1/CPATU-Doc120.pd

Curves and surfaces making a constant angle with a parallel transported direction in Riemannian spaces

In the last two decades, much effort has been dedicated to studying curves and surfaces according to their angle with a given direction. How- ever, most findings were obtained using a case-by-case approach, and it is often unclear what is a consequence of specificities of the ambient manifold and what could be generic. In this work, we propose a theo- retical framework to unify parts of these findings. We study curves and surfaces by prescribing the angle they make with a parallel transported vector field. We show that the characterization of Euclidean helices in terms of their curvature and torsion is also valid in any Riemannian manifold. Among other properties, we prove that surfaces making a con- stant angle with a parallel transported direction are extrinsically flat ruled surfaces. We also investigate the relation between their geodesics and the so-called slant helices. We prove that surfaces of constant angle are the rectifying surface of a slant helix, i.e., the ruled surface with rulings given by the Darboux field of the directrix. We characterize recti- fying surfaces of constant angle or, equivalently, when their geodesics are slant helices. As a corollary, we show that if every geodesic of a surface of constant angle is a slant helix, the ambient manifold is flat. Finally, we characterize surfaces in the product of a Riemannian surface with the real line making a constant angle with the vertical real direction

Does cultural background influence the dissemination and severity of the COVID-19 pandemic?

The COVID-19 pandemic has spread throughout the globe affecting countries worldwide. However, several differences have been observed in the number of daily new cases, the COVID-19 reproduction rate, and the severity of the disease in different countries. Previous studies have mostly highlighted government restriction policies to mitigate the pandemic effects as reasons for such differences. This study focuses on 101 countries and proposes that each country’s cultural background is also accountable for such differences. We considered the six Hofstede’s cultural dimensions (power distance, individualism, masculinity, uncertainty avoidance, long term orientation, and indulgence) and statistically analyzed their correlation with several COVID-19 impact metrics in comparison to several restriction policies. Our results support our claim that national culture influences both acceptance and subsequent adoption of restriction policies and the implementation by each government of those policies. We highlight that the attitudes towards and trust in political institutions, policies and governance is influenced by the cultural background, which is reflected in the pandemic numbers. As a main takeaway from this study, we conclude that data-driven models which aim at predicting the pandemic impact evolution at a global scale should also include variables that reflect the cultural background of each nation.info:eu-repo/semantics/publishedVersio