Experimental assessment of RRM techniques in 5 GHz dense WiFi networks using REMs

“© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.”The increasing acceptance of WiFi has created unprecedented levels of congestion in the unlicensed frequency bands, especially in densely populated areas. This results mainly because of the unmanaged interference and uncoordinated op- eration between WiFi access points. Radio Environment Maps (REM) have been suggested as a support for coordination strategies that optimize the overall WiFi network performance. In this context, the main objective of this experiment is to assess the benefit of a coordinated management of radio resources in dense WiFi networks at 5 GHz band, using REMs for indoor scenarios. It was shown that REMs can detect the presence of interfering links on the network or coverage holes, and a suitable coordination strategy can use this information to reconfigure Access Points (AP) channel assignment and re-establish the client connection, at a cost of diminishing the aggregate throughput of the network. The technique of AP hand-off was tested to balance the load from one AP to another. Using REMs, the Radio Resource Management (RRM) strategy could reconfigure the network to optimize the client distribution among available APs. Although the aggregate throughput is lower after load balancing, the RRM could increase the throughput of the overloaded AP.info:eu-repo/semantics/publishedVersio

Resposta a incidentes de segurança da informação: uma abordagem DOTMLPI-I

O conceito de ciberespaço resulta da interligação das redes de comunicações e de diferentes sistemas de informação à escala global. A abstração deste espaço de comunicações apresenta evidentes vantagens para a sociedade de informação em que vivemos. A sua utilização maciça por indivíduos e organizações fez com que ele se tornasse crítico para as empresas e para o próprio estado, pois a exploração das vulnerabilidades dos diferentes sistemas que o utilizam podem afetar as infraestruturas que prestam serviços críticos à sociedade. Para assegurar a qualidade da informação que nele circula é necessário que existam mecanismos de monitorização permanentes, com capacidade de prevenção e resposta aos incidentes que coloquem em causa a segurança da informação. Existem já vários modelos e normativos para a organização desta capacidade de resposta a incidentes de segurança da informação. Neste artigo iremos apresentar a metodologia utilizada pela OTAN para a edificação de capacidades operacionais, aplicando-a à identificação dos elementos críticos a considerar na edificação de uma capacidade de resposta a incidentes de segurança da informação no ciberespaço.The concept of Cyberspace results from - on a global scale - the interconnection of communication networks and different information systems. This immense communication space produces clear benefits for the information society in which we live. Its massive use by individuals and organizations made him critical for companies and for the state itself, since exploiting vulnerabilities of different systems that they use may affect the infrastructures that deliver critical services to society. There has to be permanent monitoring mechanisms - capable in prevention and response to incidents that may undermine the security of information - to ensure the quality of the information that flows. There are already several models and standards for organizing the capacity to respond to information security incidents. In this article we will present the methodology used by NATO to the edification ofoperational capabilities and apply it to the identification of critical elements to consider when building onecapacity to respond to information security incidents incyberspace.info:eu-repo/semantics/publishedVersio

Cross-platform demonstrator combining spectrum sensing and a geo-location database

“Copyright © [2012] IEEE. Reprinted from ICT Future Network & Mobile Summit 2012. ISBN: 978-1-4673-0320-0. This material is posted here with permission of the IEEE. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.”After the digital switchover, a secondary access of the so-called TV White Spaces should not interfere with primary users, such as DVB-T systems and local wireless microphone devices. One consensual method for secondary spectrum users to avoid interference is to combine geo-location database with spectrum sensing. This paper describes an experimental platform that combines wireless microphone sensors with a web-based geo-location database access. Software defined radios and Internet technologies are the enabling tools in use. From test trials in a real scenario, the platform was capable to update a list of vacant channel from the geo-location database, using reliable information from blind sensing algorithms

Implementation of a Communication Protocol between a Geo-location Database and TV White Space Devices

Television White Spaces (TVWS) are a spectral opportunity, for secondary users of the spectrum to deliver broadband access to rural areas. Most of the approaches now under test worldwide use a geo-location database to inform secondary users of the available channels, and avoid interference with primary users of the spectrum. The secondary network should follow a approach capable to communicate with a geo-location spectrum database, to store and retrieve information on spectrum occupancy, location of DVB-T broadcast towers and wireless microphones, maximum EIRP of secondary White Space devices (WSDs), sensing activity and other technical parameters. One group from the Internet Engineering Task Force (IETF) is presently working on the definition of a protocol to access white spaces databases – PAWS. The IETF draft protocol was chosen and considered flexible enough to be adapted for the CREW-TV project model and requirements, since it is more comprehensive and less specific on details than other proposals.info:eu-repo/semantics/publishedVersio

A era da frustração: melancolia, contra-utopia e violência em Clube da luta

Este ensaio procura traçar um panorama das polêmicas travadas em torno do filme Clube da luta, abordando algumas temáticas que se interpenetram com a questão da violência na sociedade contemporânea. A partir daí procura estabelecer relações não somente com a estética fílmica produzida pelo diretor David Fincher, mas também com as possíveis perspectivas que este filme pode constituir na problematização mais acurada do que Zizek denominou de "desertificaçao do real".This essay attempts to give an overview of the polemics around the movie Fight Club, treating some issues that intertwine with the question of violence in contemporary society. From there on it attempts to establish relations not only with the movie esthetics produced by director David Fincher, but also with possible perspectives that this movie could become a more accurate problematic of what Zizek called deserting reality

Simulating the effects of mobility restrictions in the spread of SARS-CoV-2 in metropolitan areas in Portugal

Copyright: © 2022 Oliveira et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Commuting flows and long-distance travel are important spreading factors of viruses and particularly airborne ones. Therefore, it is relevant to examine the association among diverse mobility scenarios and the spatial dissemination of SARS-CoV-2 cases. We intended to analyze the patterns of virus spreading linked to different mobility scenarios, in order to better comprehend the effect of the lockdown measures, and how such measures can be better informed. We simulated the effects of mobility restrictions in the spread of SARS-CoV-2 amongst the municipalities of two metropolitan areas, Lisbon (LMA) and Porto (PMA). Based on an adapted SEIR (Suscetible-Exposed-Infected-Removed) model, we estimated the number of new daily infections during one year, according to different mobility scenarios: restricted to essential activities, industrial activities, public transport use, and a scenario with unrestricted mobility including all transport modes. The trends of new daily infections were further explored using time-series clustering analysis, using dynamic time warping. Mobility restrictions resulted in lower numbers of new daily infections when compared to the unrestricted mobility scenario, in both metropolitan areas. Between March and September 2020, the official number of new infections followed overall a similar timeline to the one simulated considering only essential activities. At the municipal level, trends differ amongst the two metropolitan areas. The analysis of the effects of mobility in virus spread within different municipalities and regions could help tailoring future strategies and increase the public acceptance of eventual restrictions.This work was financed by national funds through FCT—Portuguese Foundation for Science and Technology, I.P., under the framework of the project “TRIAD - health Risk and social vulnerability to Arboviral Diseases in mainland Portugal” [PTDC/GES -OUT/30210/2017] and by the Research Unit UIDB/00295/2020 and UIDP/00295/2020. This study was also funded by FEDER through the Operational Programme Competitiveness and Internationalization and national funding from the Foundation for Science and Technology – FCT (Portuguese Ministry of Science, Technology and Higher Education) under the EPIUnit (UIDB/04750/2020). AIR was supported by National Funds through FCT, under the programme of ‘Stimulus of Scientific Employment – Individual Support’ within the contract CEECIND/02386/2018.info:eu-repo/semantics/publishedVersio

Life Cycle Assessment of a Multi-Material Car Component

Background, Aims and Scope. In recent years, the automotive industry has been experiencing an increasing concern with environmental requirements. A particular focus is being given to light-weighting of cars, to reducing fuel consumption and to the use of different recycling materials. Consequently, decisions on product design and development must involve economic and technological as well as environmental considerations. In adequate conditions, the LCA methodology enables one to assist an effective integration of the environmental considerations in the decision- making process [1]. In this paper, a multi-material car component which is part of the current automotive brake system, has been modified by its original manufacturer. Such a modification included the use of a new multi-material injection moulding process and the consumption of recyclable materials. The new and the current component were comparatively assessed throughout their life cycles in order to evaluate their respective environmental impacts and, thus, to verify if the new component offers a lower environmental load. The results described in this paper are part of the outcome of a broader research project involving industrial companies, university, technological centres and research institutes based in Portugal, Spain and Germany

Combination of a geolocation database access with infrastructure sensing in TV bands

This paper describes the implementation and the technical specifications of a geolocation database assisted by a spectrum-monitoring outdoor network. The geolocation database is populated according to Electronic Communications Committee (ECC) report 186 methodology. The application programming interface (API) between the sensor network and the geolocation database implements an effective and secure connection to successfully gather sensing data and sends it to the geolocation database for post-processing. On the other hand, the testbed allows authorized TV white space devices to gain access to the services of the geolocation database, according to a draft implementation of Internet Engineering Task Force (IETF) Protocol to Access White Space (PAWS) Two experimental methodologies are available with the testbed: one focused on coexistence studies with commercial wireless microphones, when the testbed is used for sensing only, and another for demonstration purposes, when the testbed is also used to emulate wireless microphone signals. Overall, this hybrid approach is a promising solution for the effective use of TV white spaces and for the coexistence with digital TV broadcast signals, or dynamic incumbent systems, such as unregistered wireless microphones

Depressão, Suporte Social, Funcionamento Executivo, Funcionalidade, e Qualidade de Vida em Idosos Institucionalizados

Aim: Our aim was to study the executive functioning, functionality, and quality of life of institutionalized old aged persons and to determine the potential roles of self-reported depression and satisfaction with social support on these domains. Method: The sample comprised 36 volunteers (13 males and 23 females) aged between 71 and 94 years. The measures used consisted of well-established battery of neuropsychological tests. A comparative study was performed. Results: Participants with depressive symptoms shown impaired executive functioning. Cognitive flexibility, functionality in instrumental activities of daily living, and quality of life are more affected in participants with higher levels of depression that also report higher levels of satisfaction with social support. Conclusion: This result is intriguing and may highlight the relevance of considering not only depression, but also factors related to social isolation and loneliness in the explanation of cognitive performance, functionality, and quality of life.Objetivo: O nosso objetivo foi estudar o funcionamento executivo, a funcionalidade, e a qualidade de vida em idosos institucionalizados, e determinar o papel da depressão e da satisfação com o suporte social nestes domínios. Método: Participaram 36 voluntários (13 do sexo masculino e 23 do sexo feminino) com idades compreendidas entre 71 e 94 anos. Neste estudo comparativo a avaliação foi realizada através da aplicação de uma bateria constituída por reconhecidos testes neuropsicológicos. Resultados: Os participantes com sintomatologia depressiva demonstraram um nível de funcionamento executivo inferior aos participantes sem depressão. A flexibilidade cognitiva, a funcionalidade, e a qualidade de vida encontram-se mais comprometidas em indivíduos com sintomatologia depressiva que relataram níveis elevados de satisfação com o suporte social. Conclusão: Embora surpreendente, o resultado deste estudo sublinha a importância de, na explicação do funcionamento executivo, funcionalidade, e qualidade de vida das pessoas mais velhas, se considerar não só a depressão, mas também outros fatores relacionados com o isolamento social e a solidão

Determinação da concentração de radão num estabelecimento de ensino público

O radão é um gás nobre, radioactivo, que tem origem na cadeia de decaimento do urânio. Como não reage quimicamente, ao ser libertado espontaneamente dos maciços rochosos, onde é produzido, ou ao dissolver-se na água contida nos poros de materiais geológicos, mistura-se facilmente com o ar. Em termos geológicos a Guarda pode ser caracterizada pela abundância de diversos tipos de granitos. Em alguns locais, a predominância de determinados minerais uraníferos e a existências de falhas podem ser responsáveis pela presença de uma certa quantidade de radiação natural, semelhante à que é detectável em outras zonas do país. A realização de medidas de actividade alfa e gama, no interior de edifícios, é de vital importância, visto que um elevado teor de radão afecta a qualidade do ar do seu interior, podendo da sua inalação resultar um significativo incremento no aparecimento de cancro do pulmão. A Organização Mundial da Saúde classifica, desde 1988, o radão como cancerígeno e recomenda que a concentração de radão habitacional não ultrapasse os 100Bq/m3. As escolas estão abrangidas pelo disposto no Decreto-Lei 79/2006, que regulamenta a qualidade do ar interior. No que diz respeito ao radão, este decreto estabelece a obrigatoriedade de pesquisa nos distritos endémicos (Braga, Vila Real, Porto, Guarda, Viseu e Castelo Branco), fixando o limite máximo a observar para a sua concentração nos edifícios construídos em 400Bq/m3 (a recomendação 90/143/EURATOM fixa a concentração deste gás no interior dos edifícios em 200Bq/m3 para as novas construções e em 400Bq/m3 para as já existentes). O objectivo deste trabalho consiste em identificar zonas de incidência de concentrações de radão, superiores ao limite máximo estipulado por lei, no interior da Escola Secundária da Sé (Guarda) e identificar áreas prioritárias em termos de aplicação de um eventual Plano de Mitigação. De forma a obter um perfil de densidades, horizontal e vertical, de concentração de radão foram colocados, uniformemente, por toda a área escolar, 120 detectores passivos do tipo LR-115 II (108 detectores LR-115 II da Kodak-Pathé manufacturados e 12 detectores LR-115 II fornecidos pelo Instituto Tecnológico e Nuclear). Para correlacionar a concentração de radão com a emissão de radiação gama, esta medição foi feita em todas as divisões onde foram colocados os detectores passivos. No cálculo da concentração de radão utilizou-se um método, simples e inovador, de contagem da densidade de traços recorrendo ao programa LEOWorks (disponível gratuitamente, na internet, pela Agência Espacial Europeia). Este método revelou-se uma importante ferramenta para se obter a concentração de radão de uma forma mais rápida, simples e económica.Radon is a noble radioactive gas originating in the decay chain of uranium. Since it does not react chemically, it easily mixes with the air as it is released spontaneously from the rock massifs where it is produced, or when it dissolves in the water stored in the pores of geological material. Geologically Guarda can be characterised by the great quantity of several types of granite. In some places, the predominance of certain uranium minerals and the existence of faults may be responsible for the existence of a certain amount of natural radiation, similar to the amount found in other areas of the country. It is vital to measure the alpha and gamma activity indoors, since a high level of radon affects the quality of the air inside buildings, and its inhalation may result in a significant increase of the risk of lung cancer. In 1988 the World Health Organisation classified radon as a carcinogen and they recommend that radon concentration indoors should not exceed 100Bq/m3 . Schools are submitted to Decree 79/2006, which rules the quality of the air indoors. In what concerns radon, this decree mandates research in the endemic districts (Braga, Vila Real, Porto, Guarda Viseu and Castelo Branco). It also establishes that 400Bq/m3 is the maximum limit to the concentration of radon in buildings (recommendation 90/143/ EURATOM establishes the limit to the concentration of this gas in 200Bq/m3 inside new buildings and in 400Bq/m3 inside the old ones). The purpose of this research is to identify areas of incidence of radon concentration above the legal maximum limit inside Sé Secondary School, in Guarda, and to identify priority areas for the use of an eventual Mitigation Plan. 120 passive detectors, type LR-115 II (108 manufactured Kodak-Pathé LR-115 II detectors and 12 LR-115 II detectors supplied by the Technological and Nuclear Institute) were evenly placed all over the school area in order to obtain a horizontal and vertical density profile of the concentration of radon. This measurement was undertaken in all the rooms where the passive detectors had been placed, so that we could correlate the concentration of radon with the emission of gamma radiation. To calculate the concentration of radon we used a simple and innovative method to count the density of traits, with the help of the programme LEOworks (European Space Agency). This method has become an important tool to obtain the concentration of radon in a quicker, simpler and more economic way