System-on-chip field-programmable gate array design for onboard real-time hyperspectral unmixing

Hyperspectral instruments have been incorporated in satellite missions, providing large amounts of data of high spectral resolution of the Earth surface. This data can be used in remote sensing applications that often require a real-time or near-real-time response. To avoid delays between hyperspectral image acquisition and its interpretation, the last usually done on a ground station, onboard systems have emerged to process data, reducing the volume of information to transfer from the satellite to the ground station. For this purpose, compact reconfigurable hardware modules, such as field-programmable gate arrays (FPGAs), are widely used. This paper proposes an FPGA-based architecture for hyperspectral unmixing. This method based on the vertex component analysis (VCA) and it works without a dimensionality reduction preprocessing step. The architecture has been designed for a low-cost Xilinx Zynq board with a Zynq-7020 system-on-chip FPGA-based on the Artix-7 FPGA programmable logic and tested using real hyperspectral data. Experimental results indicate that the proposed implementation can achieve real-time processing, while maintaining the methods accuracy, which indicate the potential of the proposed platform to implement high-performance, low-cost embedded systems, opening perspectives for onboard hyperspectral image processing.

Sistema de contagem de tráfego e classificação automática de veículos, em tempo real e sem fios

Esta tese tem por objectivo o desenho e avaliação de um sistema de contagem e classificação de veículos automóveis em tempo-real e sem fios. Pretende, também, ser uma alternativa aos actuais equipamentos, muito intrusivos nas vias rodoviárias. Esta tese inclui um estudo sobre as comunicações sem fios adequadas a uma rede de equipamentos sensores rodoviários, um estudo sobre a utilização do campo magnético como meio físico de detecção e contagem de veículos e um estudo sobre a autonomia energética dos equipamentos inseridos na via, com recurso, entre outros, à energia solar. O projecto realizado no âmbito desta tese incorpora, entre outros, a digitalização em tempo real da assinatura magnética deixada pela passagem de um veículo, no campo magnético da Terra, o respectivo envio para servidor via rádio e WAN, Wide Area Network, e o desenvolvimento de software tendo por base a pilha de protocolos ZigBee. Foram desenvolvidas aplicações para o equipamento sensor, para o coordenador, para o painel de controlo e para a biblioteca de Interface de um futuro servidor aplicacional. O software desenvolvido para o equipamento sensor incorpora ciclos de detecção e digitalização, com pausas de adormecimento de baixo consumo, e a activação das comunicações rádio durante a fase de envio, assegurando assim uma estratégia de poupança energética. Os resultados obtidos confirmam a viabilidade desta tecnologia para a detecção e contagem de veículos, assim como para a captura de assinatura usando magnetoresistências. Permitiram ainda verificar o alcance das comunicações sem fios com equipamento sensor embebido no asfalto e confirmar o modelo de cálculo da superfície do painel solar bem como o modelo de consumo energético do equipamento sensor.

Reconfigurable antenna for mobile devices

O trabalho descrito nesta dissertação de mestrado foca-se em geral na investigação de antenas impressas. São apresentados conceitos básicos, em conjunto com alguns exemplos desenvolvidos. No entanto, o principal foco prende-se com técnicas de miniaturização e reconfigurabilidade de antenas. A miniaturização de antenas é um tema de investigação de longa data, no entanto, novas técnicas e soluções são apresentadas regularmente. Nesta tese, é aplicada uma técnica recente, baseada na introdução de indutores encapsulados no elemento ressonante de uma antena, que permite miniaturizar um monopólio impresso com uma frequência de ressonância de 2.5 GHz. Outro assunto abordado neste trabalho é a reconfigurabilidade de antenas. Algumas das técnicas mais comuns na investigação actual são apresentadas e debatidas. Uma solução com recurso a díodos PIN é usada para estudar esta capacidade. Os conceitos e características deste tipo de componentes são apresentadas sendo feito o desenho e fabrico de um possível monopólio impresso reconfigurável para operação em dupla banda. Por fim, são combinadas as técnicas de miniaturização com inductor encapsulado e reconfigurabilidade através de díodos PIN, por forma a projectar uma antena reconfigurável muito pequena, para operação em duas bandas distintas. Os resultados são discutidos e com base nestes, algumas possíveis otimizações são propostas. The work reported in this dissertation is focused in the printed antenna research. Basic concepts of printed antennas are presented, along with a few examples that were developed. The main focus however, is around miniaturization and reconfigurability of antennas. Antenna miniaturization is a long time research subject, however, new techniques and solutions are presented everyday. In this thesis, a recent technique based on the introduction of chip inductors in the resonating element of a printed antenna is used in order to miniaturize a monopole with a resonating frequency at 2.5 GHz. Another issue approached in this work is antenna reconfigurability. Some common techniques used in antenna reconfiguration are presented and debated. A solution with PIN diodes is used to study this capability. The concepts and characteristics of this type of components are presented and an example of a reconfigurable printed monopole for dual-band operation is designed and fabricated. At last, miniaturization with chip inductor and reconfigurability through PIN diodes are used together to create a very small antenna for dual-band operation. The simulated and measured results are discussed and upon these, some possible optimizations are proposed.

A 5GHz/1.8V CMOS Active Balun Integrated with LNA

The development of high performance monolithic RF front-ends requires innovative RF circuit design to make the best of a good technology. A fully differential approach is usually preferred, due to its well-known properties. Although the differential approach must be preserved inside the chip, there are cases where the input signal is single-ended such as RF image filters and IF filters in a RF receiver. In these situations, a stage able to convert single-ended into differential signals (balun) is needed. The most cited topology, which is capable of providing high gain, consists on a differential stage with one of the two inputs grounded. Unfortunately, this solution has some drawbacks when implemented monolithically. This work presents the design and simulated results of an innovative high-performance monolithic single to differential converter, which overcomes the limitations of the circuits.The integration of the monolithic active balun circuit with an LNA on a 0.18μm CMOS process is also reported. The circuits presented here are aimed at 802.11a. Section 2 describes the balun circuit and section 3 presents its performance when it is connected to a conventional single-ended LNA. Section 4 shows the simulated performance results focused at phase/amplitude balance and noise figure. Finally, the last section draws conclusions and future work.

Sistema de multiprocessamento para simulação de N-corpos em FPGA

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia de Electrónica e Telecomunicações

A aprendizagem da leitura e da escrita partindo de texto

Projeto de Intervenção apresentado à Escola Superior de Educação de Lisboa para a obtenção de grau de Mestre em Didática da Língua Portuguesa no 1º e 2º CEB

Concorrência fiscal prejudicial

Mestrado em Fiscalidade

Enlarging the window for radiative leptogenesis

We investigate the scenario of resonant thermal leptogenesis, in which the leptonic asymmetries are generated through renormalization group corrections induced at the leptogenesis scale. In the framework of the standard model extended by three heavy Majorana neutrinos with masses M(1) = M(2) << M(3) at some high scale, we show that the mass splitting and CP-violating effects induced by renormalization group corrections can lead to values of the CP asymmetries large enough for a successful leptogenesis. In this scenario, the low-energy neutrino oscillation data can also be easily accommodated. The possibility of having an underlying symmetry behind the degeneracy in the right-handed neutrino mass spectrum is also discussed. (c) 2005 Elsevier B.V. All rights reserved.

A SON Enhanced Algorithm for Observed Time Differences Based Geolocation in Real 3G Networks

Conferência - 16th International Symposium on Wireless Personal Multimedia Communications (WPMC)- Jun 24-27, 2013

James W. Carey as critical theorist of the information age

This paper suggests that the thought of the North-American critical theorist James W. Carey provides a relevant perspective on communication and technology. Having as background American social pragmatism and progressive thinkers of the beginning of the 20th century (as Dewey, Mead, Cooley, and Park), Carey built a perspective that brought together the political economy of Harold A. Innis, the social criticism of David Riesman and Charles W. Mills and incorporated Marxist topics such as commodification and sociocultural domination. The main goal of this paper is to explore the connection established by Carey between modern technological communication and what he called the “transmissive model”, a model which not only reduces the symbolic process of communication to instrumentalization and to information delivery, but also politically converges with capitalism as well as power, control and expansionist goals. Conceiving communication as a process that creates symbolic and cultural systems, in which and through which social life takes place, Carey gives equal emphasis to the incorporation processes of communication.If symbolic forms and culture are ways of conditioning action, they are also influenced by technological and economic materializations of symbolic systems, and by other conditioning structures. In Carey’s view, communication is never a disembodied force; rather, it is a set of practices in which co-exist conceptions, techniques and social relations. These practices configure reality or, alternatively, can refute, transform and celebrate it. Exhibiting sensitiveness favourable to the historical understanding of communication, media and information technologies, one of the issues Carey explored most was the history of the telegraph as an harbinger of the Internet, of its problems and contradictions. For Carey, Internet was seen as the contemporary heir of the communications revolution triggered by the prototype of transmission technologies, namely the telegraph in the 19th century. In the telegraph Carey saw the prototype of many subsequent commercial empires based on science and technology, a pioneer model for complex business management; an example of conflict of interest for the control over patents; an inducer of changes both in language and in structures of knowledge; and a promoter of a futurist and utopian thought of information technologies. After a brief approach to Carey’s communication theory, this paper focuses on his seminal essay "Technology and ideology. The case of the telegraph", bearing in mind the prospect of the communication revolution introduced by Internet. We maintain that this essay has seminal relevance for critically studying the information society. Our reading of it highlights the reach, as well as the problems, of an approach which conceives the innovation of the telegraph as a metaphor for all innovations, announcing the modern stage of history and determining to this day the major lines of development in modern communication systems.

Many-core approach to 2D-DCT calculation using an FPGA

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia de Electrónica e Telecomunicações

Estudo sobre a memória longa na volatilidade dos preços do ouro : uma abordagem com base nos modelos de tipo ARCH

Mestrado em Contabilidade e Análise Financeira

Para lá dos jornalistas: influencer relations, uma nova era de Media Relations

Dissertação apresentada à Escola Superior de Comunicação Social como parte dos requisitos para obtenção de grau de mestre em Gestão Estratégica das Relações Públicas.

Compact, frequency reconfigurable, printed monopole antenna

This paper proposes a possible implementation of a compact printed monopole antenna, useful to operate in UMTS and WLAN bands. In order to accomplish that, a miniaturization technique based on the application of chip inductors is used in conjunction with frequency reconfiguration capability. The chip inductors change the impedance response of the monopole, allowing to reduce the resonant frequency. In order to be able to operate the antenna in these two different frequencies, an antenna reconfiguration technique based on PIN diodes is applied. This procedure allows the change of the active form of the antenna leading to a shift in the resonant frequency. The prototype measurements show good agreement with the simulation results.

ALS-Sence: sistema de aquisição e processamento de electromiogramas para pacientes com ALS

Dissertação para obtenção do grau de Mestre em Engenharia de Eletrónica e Computadores