Time-scale analysis non-local diffusion systems, applied to disease models

The objective of the present paper is to use the well known Ross-Macdonald models as a prototype, incorporating spatial movements, identifying different times scales and proving a singular perturbation result using a system of local and non-local diffusion. This results can be applied to the prototype model, where the vector has a fast dynamics, local in space, and the host has a slow dynamics, non-local in space

'Technical Safety’ or ‘System Safety’? Why Names Matter

By providing safety and risk management consulting services, we have the opportunity to be regularly involved with clients from a number of different industries. We often interact with professionals of varied trajectories and backgrounds, many of whom have never received comprehensive training in system safety. Those individuals are by no means less competent in their jobs; however, their schooling in system safety often comes from a senior colleague or mentor who held a safety-related position during a long career in a single industry. More often than not, the individual’s understanding of system safety is reduced to his or her limited exposure to this rich and diverse field

Reduction of total harmonic distortion in power inverters

The output voltage of PWM power inverters shows harmonic distortion due to several causes; the main ones are the modulation algorithm, nonlinearities in the output filter, dead times, voltage drops across the switches and modulation of the dc bus voltage. The distortion is more evident when using low dc bus voltages. As a result, motors driven by these inverters have important torque pulsations. This work proposes to reduce the distortion produced by dead times and voltage drops across the switches using a simple algorithm that recalculates the width of each PWM pulse, while preserving the ideal area. By simulation, the THD was reduced from 18% to 0.29% in a single-phase inverter. The proposed algorithm only needs products and sums, so it is suitable for being implemented on a DSP with a very low processing load.Fil: Oliva, Alejandro Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Chiacchiarini, Hector Gerardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Aymonino, Oscar Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; ArgentinaFil: Mandolesi, Pablo Sergio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages". Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras. Instituto de Investigaciones en Ingeniería Eléctrica "Alfredo Desages"; Argentin

Improvements of Pan-European IDM Architecture to Enable Identity Delegation Based on X.509 Proxy Certificates and SAML

To foster the secure use of telematic services provided by public institutions, most European countries – and others in the rest of the world – are promoting electronic identification systems among their citizens to enable fully reliable identification. However, in today’s globalized environment, it is becoming more common for citizens and entities of a given country, with their own electronic credentials under the legal framework of their country, to seek access to the public services provided by other countries with different legal frameworks and credentials. At present, a number of projects in the European Union are attempting to solve the problem through the use of pan-European identity management systems that ensure interoperability between the public institutions of different Member States. However, the solutions adopted to date are inadequate, for they do not envision all possible cases of user interaction with institutions. Specifically, they fail to address a very important aspect provided in different national legal systems, namely delegation of identity, by which a citizen can authorize another to act on his or her behalf in accessing certain services provided by public institutions. This paper provides a thorough analysis of problems of delegation and proposes an architecture based on X.509 Proxy Certificates and SAML assertions to enable delegation in provision of services in the complex and heterogeneous environment presented by the public institutions of the European Union as a whole

Minimization procedure of experimental tests for calibration purposes, within HVAC&R energy efficiency framework

Simulation models and predictive tools need to be fast, accurate and robust at the same time. The models that have to provide numerical solutions under transient conditions for a long period of time need to be simple with the aim of minimizing the time respond, without losing the accuracy. Thus, previous experimental data and a calibration methodology are necessary to assure this objective, both are strictly necessary to reproduce the behaviour with accuracy expected. Consequently, even accurate information (e.g. look-up tables) for HVAC&R components (e.g. heat exchangers, fan/compressor, auxiliary elements, etc.) is known and all coupling system is developed, the minimization of experimental tests for calibration purposed based scattered data interpolation is now an important aspect, which looks for reducing the quantity of experiments necessary to assure the accuracy expected from an optimization point of view. The present work shows an optimization procedure based on test number minimization according detailed error comparison against existing previous data. Illustrative results for a specific component are presented highlighting test number reduction without losing accuracy.This project has received funding from the Clean Sky 2 Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 755517.Peer ReviewedPostprint (published version

Asymptotic behavior of a reaction-diffusion problem with delay and reaction term concentrated in the boundary

In this work we analyze the asymptotic behavior of the solutions of a reaction-diffusion problem with delay when the reaction term is concentrated in a neighborhood of the boundary and this neighborhood shrinks to boundary, as a parameter goes to zero. This analysis of the asymptotic behavior uses, as a main tool, the convergence result found in [3]. Here, we prove the existence of a family of global attractors and that this family is upper semicontinuous at = 0. We also prove the continuity of the set of equilibria at = 0. 

Open Innovation, Soft Branding and Green Influencers: Critiquing 'Fast Fashion' and 'Overtourism'

This paper explores digital reality replication for cultural consumption and green-digital open-system innovation, along with responsible, sustainable practices fashioned in a post-COVID-19 era. We address these after the dystopian effects of lockdown on global tourism and, in particular, the looming crisis of unsustainable 'overtourism'. The aim of this paper is to disclose problems and policies related to moderating consumption to more sustainable levels. The scope of the article tackles three fields: urban re-branding, fast fashion, and overtourism. Each problem area is analysed against the background of digital surveillance in the attention economy with the aid of a conceptual model. Accordingly, the principal objectives of this paper are to analyse key sustainability problem sources, evolutionary processes, and policy responses. The paper's originality and value lie in its recognition of tractable problem engagement through conceptual and practicable methods. This contribution also explores other consumption modes that tourists appreciate, namely, retail activity and its unsustainable "fast fashion" obsession. Finally, the paper analyses urban soft branding, the third tourism attractor within the niche touristic activity of the creative-cultural and gastronomic kind, which also features impulses that affect the perpetuation of unsustainable touristic practices. Thus, this contribution also assesses various studies on tourism futures that exploit digital media to assist in conserving both natural and cultural environments. Accordingly, we first narrate the soft re-branding of an "Art City" as a "Fashion City" and consider the example of green-digital innovation in the cultural milieu of Florence, Italy, in light of criticism of the unsustainability of "fast fashion". We consider which actions are envisioned or advised in the similarly "over-touristed" city of Venice. In a different vein, we consider whether the mobilisation of 'pop celebrity' performers such as audience engagers or influencers works for sustainable intervention through an assessment of the cultural interventions of Madonna in Lisbon. Finally, we anatomise "green" politics and policies for creative-cultural cities with the support of digital media to influence sustainable actions to moderate or, alternatively, revitalise polluted, congested, or otherwise over-touristed city centres. The greening of central Paris, Barcelona, Milan, and London offer a a series of examples of this type of moderation and revitalisation. Keywords: digital reproduction; open innovation; lockdown; overtourism; soft branding; influencer

Diseño de antenas en tecnología Gap Waveguide

Este proyecto se va a centrar en la realización de un diseño de un array de ranuras en una nueva tecnología denominada Groove Gap Waveguide y a comparar sus prestaciones con un diseño en guía rectangular convencional. La tecnología Gap Waveguide, diseñada para longitudes de onda de milímetros e inferiores, se implementa mediante dos planos conductores perfectos (PEC) sin que exista contacto eléctrico entre ellos, a uno de los planos se le añade una estructura periódica formada por pines, llamada 'bed of nails', para que se cree una región de alta impedancia y se comporte casi como un conductor magnético perfecto (PMC). Teóricamente si se coloca el PMC debajo de un PEC a una distancia menor de λ/4 no existe propagación de ningún modo entre las dos placas. Si se realiza un camino entre los pines, se consigue una propagación por dicho camino sin la necesidad de buen contacto eléctrico y sin afectar a la 'bed of nails'. Una de las características de estas estructuras periódicas es que poseen una banda de frecuencias de corte llamada stopband, en la que no es posible la propagación de ningún tipo de onda electromagnética. Así pues nuestro trabajo comenzará con el diseño de esta superficie, de manera que la frecuencia de trabajo seleccionada para el funcionamiento de la antena (10 GHz) esté dentro de la stopband de la superficie. Su diseño se basa en el cálculo de diagramas de dispersión y los parámetros que definen la posición de la stopband son las dimensiones de los pines utilizados, su periodicidad y la distancia a la tapa superior metálica, denominada GAP que da nombre a esta tecnología. Una vez diseñada esta estructura se procederá a realizar el diseño completo de la antena Groove Gap Waveguide variando el número de filas pines y analizando las prestaciones de las mismas. El diagrama de radiación seguirá unas especificaciones indicadas a priori y radiará a partir de unas aberturas en forma de ranuras realizadas de forma longitudinal en una de las placas de la guía. La distribución de estas ranuras, así como su número y tamaño, se obtendrán a partir del desarrollo de los polinomios de Chebyshev aplicados para cavidades resonantes. Por último se ha realizado un diseño, de muy bajo coste, de nuestra antena Groove Gap Waveguide, adaptándonos a limitaciones de fabricación en un entorno académico.Ingeniería de Sistemas de Comunicacione

An Atomic and Molecular Study of the Interstellar Medium Around the SNR RCW 103

We report on the detection of HCO+ and 12CO emission in the rotational transition J=1-0 in the vicinity of the shock front at the southern border of the supernova remnant RCW 103, where previous infrared observations suggest an interaction with a molecular cloud. The observations were carried out with the Australian Millimeter Radiotelescope at Mopra. We observed a depletion of HCO+ behind the supernova shock front. In addition, we studied the interstellar medium over an extended region towards RCW 103 based on archival 21 cm HI line observations from the Australia Telescope Compact Array (ATCA) and the Parkes Telescope. No atomic gas is observed in emission in coincidence with the molecular feature. This absence is interpreted in terms of self absorption processes.Comment: accepted to be published in Publications of the Astronomical Society of Australi

Aportaciones del Proyecto Votescript a los Esquemas Tradicionales de Voto Electrónico.

This paper hallmarks the most relevant contributions carried out by the authors in the VOTESCRIPT project (TIC2000-1630-C02). The main goal of this project was the analysis, definition and implementation of a system which copes with every phases and elements existing in a process of electronic voting using computer networks. A summary of the main criticisms of electronic voting is presented to disclose that the most relevant voting schemes only take into account a technological perspective, just trying to imitate the conventional voting schemes. Nevertheless in these proposals important aspects such individual and global verification are not properly undertaken. The paper includes the proposed solutions of the project to solve these mentioned problems