Partial Classification of Lorenz Knots: Syllable Permutations of Torus Knots Words

We define families of aperiodic words associated to Lorenz knots that arise naturally as syllable permutations of symbolic words corresponding to torus knots. An algorithm to construct symbolic words of satellite Lorenz knots is defined. We prove, subject to the validity of a previous conjecture, that Lorenz knots coded by some of these families of words are hyperbolic, by showing that they are neither satellites nor torus knots and making use of Thurston's theorem. Infinite families of hyperbolic Lorenz knots are generated in this way, to our knowledge, for the first time. The techniques used can be generalized to study other families of Lorenz knots

Role of reconnection in inertial kinetic-Alfvén turbulence

In a weakly collisional, low-electron-beta plasma, large-scale Alfvén turbulence transforms into inertial kinetic-Alfvén turbulence at scales smaller than the ion microscale (gyroscale or inertial scale). We propose that at such kinetic scales, the nonlinear dynamics tends to organize turbulent eddies into thin current sheets, consistent with the existence of two conserved integrals of the ideal equations, energy and helicity. The formation of strongly anisotropic structures is arrested by the tearing instability that sets a critical aspect ratio of the eddies at each scale a in the plane perpendicular to the guide field. This aspect ratio is defined by the balance of the eddy turnover rate and the tearing rate, and varies from (d [subscript]e / a)¹ / ² to d [subscript]e / a depending on the assumed profile of the current sheets. The energy spectrum of the resulting turbulence varies from k -⁸ / ³ to k -³ , and the corresponding spectral anisotropy with respect to the strong background magnetic field from [mathematical equation; see source] to [mathematical equation; see source].NSF (Grant no. NSF PHY-1707272)NASA (Grant no. NASA 80NSSC18K0646)DOE (Grant no. DE-SC0018266)NSF CAREER (Award no. 1654168)NSF-DOE Partnership in Basic Plasma Science and Engineering (Award no. DE-SC0016215

Demonstrador de mobilidade heterogénea

No âmbito da cadeira de projecto do curso de Engenharia de Computadores e Telemática, desenvolveu-se um demonstrador de mobilidade heterogénea tendo por base o projecto Europeu Moby Dick. Para além da construção do mesmo desenvolveram-se alguns pacotes de software que constituem uma mais valia para o demontrador. Por fim realizaram-se vários testes sobre o demonstrador cujos resultados são aqui apresentados.Integrated in Computers and Telematics Engineer final project, a Heterogenity and Mobility Demo was setup, using as it base the European Project Moby Dick. Having the Demo setup further software packages were developed constituting an increased value to the Demo. All done several tests were performed on the Demo whose results are presented here

Síntese e implementação de circuitos digitais reconfiguráveis dinamicamente (projecto 2)

The paper presents the results of the project proposed to the authors (who are the 4th year students of LECT) and shows how the specified problem has been solved. The description of the project and the basic requirements have been considered in the papers [1,2

Flexible manufacturing field trial

Within the European project R-Fieldbus (http://www.hurray.isep.ipp.pt/activities/rfieldbus/), an industrial manufacturing field trial was developed. This field trial was conceived as a demonstration test bed for the technologies developed during the project. Because the R-Fieldbus field trial included prototype hardware devices, the purpose of this equipment changed and since the conclusion of the project, several new technologies also emerged, therefore an update of the field trial was required. This document describes an update of the manufacturing field trial. The purpose of this update, the changes and improvements introduced are described in the document. Additionally, this document also provides a reliable source of documentation for the equipment, configuration and software components of the manufacturing field trial

Corporate social responsibility: an empirical analysis of portuguese SMEs

Mestrado em MarketingCorporate Social Responsibility has been a topic of academic and managerial discussion for several years. This subject gave birth to an extensive field of study and literature that has been gradually developing to a modern view, characterized by a broad view of social responsibility and a perception of benefits resulting from social action initiatives. Can CSR, in fact, affect an organization's performance indicators? Findings seem to unveil a positive answer concerning this issue. This quantitative study uses data gathered through a self-administered postal questionnaire to 108 small and medium-sized Portuguese organizations, concerning their orientation towards CSR. A two dimensional CSR model was used to classify the organizations in clusters related to their orientation. Organizational performance indicators were then used to uncover any differences between clusters' performance. Findings reveal that Portuguese SMEs context is characterized by two clusters of organizations - a modern view and a classical view cluster. Organizational performance indicators revealed that modern view organizational performed better in every indicator although statistical significance was only found in two of six indicators.A Responsabilidade Social das Empresas tem sido, há bastante tempo, um tópico de discussão, tanto académica como de gestão. Este tópico deu origem a um campo de literatura e estudo que gradualmente se desenvolveu até à visão moderna que prevalece hoje, caracterizando-se por uma visão alargada da responsabilidade social e uma percepção de benefícios decorrentes das acções de responsabilidade social. Pode a RSE influenciar os indicadores de performance de uma organização? A análise empírica revela uma resposta positiva relativamente a esta questão. Este estudo, de natureza quantitativa utiliza a informação recolhida de um questionário administrado por correio a uma amostra de 108 pequenas e médias empresas portuguesas, inquirindo a sua orientação em relação à Responsabilidade Social das Empresas. É utilizado um modelo bidimensional de RSE para classificar as organizações em clusters representativos da sua orientação. Posteriormente, indicadores de performance das organizações são utilizados para revelar diferenças e comparar as performances entre estes clusters. A análise empírica revela que o contexto das PMEs Portuguesas é caracterizado por dois clusters distintos de organizações - representando uma visão moderna e uma visão clássica da RSE. Os indicadores de performance organizacional revelam que o cluster representando a visão moderna demonstra um melhor desempenho em todos os indicadores, no entanto foi encontrada significância estatística apenas em dois dos indicadores

A study on the prediction of flight delays of a private aviation airline

The delay is a crucial performance indicator of any transportation system, and flight delays cause financial and economic consequences to passengers and airlines. Hence, recognizing them through prediction may improve marketing decisions. The goal is to use machine learning techniques to predict an aviation challenge: flight delay above 15 minutes on departure of a private airline. Business and data understanding of this particular segment of aviation are revised against literature revision, and data preparation, modelling and evaluation are addressed to lead towards a model that may contribute as support for decision-making in a private aviation environment. The results show us which algorithms performed better and what variables contribute the most for the model, thereafter delay on departure.O atraso de voo é um indicador fulcral em toda a indútria de transporte aéreo e esses atrasos têm consequências económicas e financeiras para passageiros e companhias aéras. Reconhecê- los através de predição poderá melhorar decisões estratégicas e operacionais. O objectivo é utilizar técnicas de aprendizagem de máquina (machine learning) para prever um eterno desafio da aviação: atraso de voo à partida, utilizando dados de uma companhia aérea privada. O conhecimento do contexto do negócio e dos dados adquiridos, num segmento singular da aviação, são revistos à luz das literatura vigente e a preparação dos dados, a modelização e respectiva avaliação são conduzidos de modo a contribuir para uma ferramenta de apoio à decisão no contexto da aviação privada. Os resultados obtidos revelam quais dos algoritmos utilizados demonstra uma melhor performance e quais as variáveis dos dados obtidos que mais contribuem para o modelo e consequentemente para o atraso à partida