On-light: optical social network

Social networks are a recent phenomenon of communication, with a high prevalence of young users. This concept serves as a motto for a multidisciplinary project, which aims to create a simple communication network, using light as the transmission medium. Mixed team, composed by students from secondary and higher education schools, are partners on the development of an optical transceiver. A LED lamp array and a small photodiode are the optical transmitter and receiver, respectively. Using several transceivers aligned with each other, this con guration creates a ring communication network, enabling the exchange of messages between users. Through this project, some concepts addressed in physics classes from secondary schools (e.g. photoelectric phenomena and the properties of light) are experimentally veri ed and used to communicate, in a classroom or a laboratory

Módulo expositivo e interactivo sobre fenómenos ópticos

As experiências interactivas são um veículo atractivo de disseminação do conhecimento, em particular no domínio da óptica e das suas aplicações. Este artigo descreve um módulo expositivo e interactivo, destinado a explicar os fenómenos físicos relacionados com a luz. O sistema assemelha-se a uma máquina de jogos, que tem no topo um conjunto de seis experiências e vem equipado com um sistema com informação visual e auditiva. Permite ao utilizador escolher qual a experiência que irá decorrer, criando um ambiente multimédia motivador para demonstrar efeitos ópticos. Pode ser utilizado tanto em ambiente de aula, como em eventos científicos ou culturais abertos à comunidade em geral. O resultado final é um módulo didáctico fiável e robusto, que integra diversas experiências e inclui soluçõesde hardware e software numa solução integrada

Bragg grating tuning techniques for interferometry applications

Fiber bragg grating is widely used in optical fiber applications as a filter or a sensor due to its compact size and high sensitivity to physical conditions, such as temperature and strain. The purpose of this chapter is to describe the implementation and characterization of two tuning methods for optical fiber Bragg gratings, varying the temperature or the length of the fiber. Among the methods using mechanical deformation, compression of the fiber by bending a flexible sheet aggregated with the Bragg grating has shown very interesting tuning results, reaching 19.0 nm with minimum reflection bandwidth variation over the entire tuning range. Stretching the fiber has presented several drawbacks, including breaking of the fiber and a lower tuning range of 4.9 nm. Temperature tuning technique presents good linearity between tuning range and temperature variation but at the cost of a low tuning range (0.4 nm) and a permanent high current electrical source.info:eu-repo/semantics/publishedVersio

Spectrum Engineering Towards 5G: Helping to Ensure Efficient and Interference-free Wireless Communications

With the current use of mobile devices across the world, with increasing demands on bandwidth resources, solving the congestion in the radio spectrum is becoming a challenging task to spectrum regulators. Radiocommunication systems must share the resources efficiently using different multiplexing techniques using space, frequency or time dimension. Sharing and compatibility studies are required to assess the possibilities for radio systems to coexist in the same or in adjacent frequency bands. SEAMCAT  (www.seamcat.org) is a software tool based on the Monte-Carlo simulation method, which is developed within the frame of European Conference of Postal and Telecommunication administrations (CEPT). This tool permits statistical modelling of different radio interference scenarios for performing sharing and compatibility studies between radio-communications systems in the same or adjacent frequency. SEAMCAT is used by many regulatory agencies across the world for various spectrum sharing and compatibility studies such as between mobile systems and terrestrial broadcasting networks.IEEE Latvia sectioninfo:eu-repo/semantics/publishedVersio

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

Desenvolvimento e teste de uma smartbox versátil para o chão de fábrica

O surgimento de várias inovações tecnológicas permitiu a digitalização e a transformação da indústria, acompanhando o paradigma da Indústria 4.0. Tecnologias ligadas à robótica, aos sensores inteligentes, ao fabrico assistido por computador, à Internet das Coisas ou à Inteligência Artificial permitem a interligação entre os mundos físicos e virtuais. A interoperação entre todos estes domínios do saber é o princípio para transformar o processo de produção e criar uma fábrica inteligente. O foco deste artigo centra-se no desenvolvimento e teste de uma smartBox, capaz de comunicar eficientemente com os equipamentos no chão de fábrica e integrá-los em plataformas de IIOT (Industrial Internet of Things). À smartBox estão acopladas cartas e módulos de sensores e atuadores adequados às especificidades de cada máquina. esta tem de ser capaz de operar em tempo-real, ter uma boa performance e escalabilidade e bons canais de comunicação. O hardware da smartBox tem, por isso, de ser robusto, flexível, escalável, funcional, suportar diferentes tecnologias e permitir atualizações futuras, características essenciais a uma disseminação do conceito de Indústria 4.0 no chão de fábrica. Atualmente, existe no mercado uma diversidade de plataformas de hardware capazes de suportar o desenvolvimento da smartBox e servir de Gateway com qualquer equipamento no chão de fábrica. Por sua vez, os controladores lógicos programáveis e as suas plataformas de programação atuais são cada vez mais versáteis e intuitivos de programar, facilitando o processo de desenvolvimento, no sentido em que cada equipamento do chão de fábrica tem a sua especificidade, processo e tecnologia. Dado que muitas instalações industriais têm alguns anos de existência, por vezes as linhas de comunicação andam a par com as linhas de potência e é necessário prestar atenção às questões das interferências e formas de as minimizar. Nesse caso, os protocolos de comunicação a utilizar devem corresponder aos requisitos necessários em comunicações industriais, tal como a redundância, tolerância a interferências, reduzida latência, e minimizar as retransmissões e a perda de pacotes de dados. Nesse âmbito, apresentamos um caso de estudo em que é analisada a vibração de um motor elétrico; testamos duas soluções distintas para a smartBox: uma é baseada num sistema de aquisição de dados da National Instruments, onde o software LabVIEW é usado para adquirir, processar e armazenar os dados num servidor OPC (Object Linking and Embedding for Process Control). A outra solução incorpora as plataformas Arduino e EtherCAT. As características de ambas as propostas são analisadas e comparadas.info:eu-repo/semantics/publishedVersio

Design-With-IoT and Design-For-Automation: A Proposal for Product Development Oriented for Excellence

This paper presents two methodologies for the design and development of new products called Design-with- IoT (DwIoT) that aims to integrate IoT technology into products, focusing on a set of guidelines for its implementation, and the concept of Design-for-Automation (DFA), important in the development of new automation oriented products in an industry 4.0 context.info:eu-repo/semantics/publishedVersio

Distributed sensing network using ultra low-power lora nodes: a case study in intensive almond groves

The digitization of various agricultural processes is a growing reality in Portugal and in the world. Some of the application areas use sensor networks to monitor several parameters, including monitoring plant growth, atmospheric conditions or optimizing the irrigation process. However, in the agricultural environment where energy sources may be scarce, the implementation of an autonomous sensor network must consider the limitations imposed by the energy consumption of sensor nodes, powered by batteries. Moreover, spatial distribution models must be tested to optimize the number of sensors and their placement in the field. This paper presents an ongoing work, being developed in partnership with a company, owner of an extensive almond grove in the region of Idanha-a-Nova and Fundão, Portugal. The objective is to implement a sensor network, making use of a LoRa technology and battery-powered nodes, and collect information on various parameters associated with intensive almond trees groves. The proposed sensor network is part of an IoT middleware framework that captures multiple data from different sources. Through smart farming, precision agriculture, real time monitoring and business intelligence solutions, the expected results are productivity increase and optimization of the use of resources in the almond cultivation process and a significative reduction of the environmental impact.N/

MOVELETUR - Turismo sustentável e mobilidade elétrica em espaços naturais

Programa de Financiamento: Programa EP INTERREG V A España-Portugal (POCTEP).MOVELETUR - Turismo Sustentável e Mobilidade Elétrica em Espaços Naturais.info:eu-repo/semantics/publishedVersio

TV white spaces maps computation through interference analysis

“Copyright © [2011] IEEE. Reprinted from ICT Future Network & Mobile Summit 2011. ISBN: 978-1-4577-0928-9. 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.”For the characterization of TV White Spaces (TVWS), an extensive simulation of the impact of interfering signals was undertaken in a generalized scenario. The simulation for these investigations was derived from a Monte Carlo methodology using SEAMCAT, and the results include the computation of TVWS maps as it can be done with the access to a geo-location database, or based on autonomous sensing only. Geo-location database approach is shown to utilize TVWS spectrum more efficiently. The impact of Professional Wireless Microphone Systems (PWMS) devices on the availability of TVWS is also analyzed and imposes additional limitations of the maximum power emitted by secondary spectrum users