ESTG - Mestrado em Engenharia Eletrotécnica - Telecomunicações
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- MILLMETER WAVE SOFTWARE DEFINED RADIOPublication . Silva, João Gonçalo Cruz; Mendes, Luís Miguel Moreira; Vaz, João Manuel Torres Caldinhas SimõesThis study presents the design, implementation, and evaluation of an advanced SDR platform that significantly enhances flexibility, performance, and expandability in wireless communication systems. The research encompasses the development of a base SDR platform operating from 100 MHz to 6 GHz, complemented by a mmWave expansion card extending the frequency range up to 40 GHz. The platform’s architecture integrates a powerful signal processing core, featuring both FPGA-based hardware processing and a quad-core ARM CPU, enabling efficient handling of complex signal processing tasks. Key features of the developed SDR platform include a wide frequency range, high bandwidth capabilities of up to 56 MHz, and flexible sampling rates up to 60 MSPS (with potential for 120 MSPS). The system incorporates MIMO 2x2 functionality and an on-board frequency synthesizer operating up to 18 GHz, enhancing its versatility for various wireless applications. The platform’s expandability is demonstrated through the successful integration of the mmWave expansion card, showcasing its readiness for next-generation wireless technologies, including 5G and beyond. Additionally, the SDR’s modular design approach, coupled with multiple power options, such as USB-PD and a high-speed PCIe interface for data offloading, ensures adaptability to diverse research scenarios and future technological advancements. Extensive laboratory and real-environment assessments validate the SDR plat form’s performance, confirming its compliance with and, in some instances, surpass ing initial design specifications. The research highlights the platform’s potential for exploring new modulation schemes, investigating spectrum sharing techniques, and developing novel wireless protocols. This work significantly contributes to the field of software defined radio, providing a robust foundation for future research in wireless communications, from IoT to fixed and cellular communications and radar systems.
- M U LT I - S E N S O R S M A RT PA C K A G E T R A C K I N G D E V I C E F O R L O G I S T I C SPublication . Susano, Rúben Rafael Pinto; Fernandes, Telmo Rui Carvalhinho Cunha; Faria, Sérgio Manuel Maciel de; Ventura, Paulo Jorge da CruzA embalagem comum tem recentemente vindo a demonstrar insuficiências na aptidão para satisfazer as expectativas do público em relação a produtos frescos, de alta qualidade e seguros. Com isto, a indústria obteve motivação para inovar e procurar novas soluções para corrigir esta lacuna. Através de estudos nesta área, a Embalagem Inovadora surgiu como uma solução viável. Este conceito foca-se principalmente em melhorar embalagens, através da integração de tecnologias de diversas áreas. O seu principal desafio reside em melhorar as embalagens, enquanto preserva ou melhora o fluxo de trabalho da cadeia de abastecimento e logística. Esta dissertação apresenta uma solução de Embalagem Inovadora, baseada em eletrónica, para monitorizar e rastrear embalagens numa cadeia de distribuição. O estudo aborda tanto o projeto como o desenvolvimento do hardware e do firmware, apresentando também os testes de desempenho realizados com vista à validação da solução desenvolvida. A solução desenvolvida consiste num sistema capaz de monitorizar temperatura, humidade, pressão atmosférica, impactos e localização das embalagens. O sistema está dividido em Package Tags e Gateways. As Package Tags encontram-se situadas dentro da embalagem e mantêm o registo de todos os valores mencionados, excluindo a localização. Os Gateways funcionam como pontes entre várias Package Tags e o servidor remoto, servindo igualmente para determinar a localização a ser associada à Package Tag. A comunicação entre as Package Tags e os Gateways é realizada utilizando o recurso PAwR do protocolo BLE. Embora este recurso tenha sido originalmente desenvolvido para etiquetas de preço ESL em supermercados, foi adaptado, durante este trabalho, para a sua aplicação em logística dentro deste sistema.
- S I S T E M A D E M O N I T O R I Z A Ç Ã O AVA N Ç A D O PA R A A Q U A P O N I APublication . Pereira, Fernando de Jesus Santos; Faria, Sérgio Manuel Maciel de; Vieira, Judite dos Santos; Fernandes, Telmo Rui Carvalhinho CunhaA monitorização da qualidade da água em sistemas de aquaponia é essencial para garantir o equilíbrio entre os organismos aquáticos e as plantas nele inserido, permitindo a deteção de variações nos parâmetros essenciais ao bom funcionamento do sistema. Neste contexto, esta dissertação apresenta o desenvolvimento e validação de dois sistemas complementares de monitorização, um para a qualidade da água na estufa e outro para a água fornecida à estufa, ambos recorrendo a sensores e comunicação sem fios para permitir uma análise contínua e remota dos parâmetros monitorizados. O primeiro sistema, instalado na estufa, integra sensores para a medição da temperatura da água, pH, condutividade elétrica (CE), sólidos dissolvidos totais (TDS) e potencial de oxidação-redução (ORP), garantindo a monitorização das condições da água utilizada na produção. Além disso, foi implementado um sistema de monitorização visual, baseado em ESP32-CAM, para acompanhar o crescimento das plantas e detetar a presença de insetos. O segundo sistema, responsável pela monitorização da água antes da sua entrada na estufa, apresenta uma arquitetura semelhante, mas foi projetado para operar em ambientes externos, exigindo uma caixa à prova de água e comunicação via NB-IoT para transmissão remota dos dados. Os sensores utilizados foram submetidos a um processo de calibração regular, assegurando medições fiáveis e dentro dos valores recomendados para sistemas de aquaponia. A análise dos dados recolhidos demonstrou que os sistemas apresentam um desempenho estável ao longo do tempo, permitindo a deteção de variações nos parâmetros indicadores da qualidade da água e facilitando a tomada de decisões para a manutenção do equilíbrio do sistema. A integração da monitorização vi sual mostrou-se uma ferramenta complementar importante, permitindo validar as condições do crescimento das plantas e a presença de pragas de forma remota. Os resultados confirmam a eficácia dos sistemas desenvolvidos, reduzindo a necessidade de intervenções manuais e proporcionando uma solução eficiente e modular para a monitorização de ambientes aquapónicos.
- ROI -BASED CODING OF BIOMEDICAL IMAGES FOR MACHINE ANALYSISPublication . Nicolau, Daniel Filipe da Silva; Faria, Sérgio Manuel Maciel de; Távora, Luís Miguel de Oliveira Pegado de Noronha e; Thomaz, Lucas ArrabalThe increasing volume of data acquired and generated daily in the healthcare sector, driven by technological advancements, brings significant benefits to patient diagnosis and research. However, this growth also presents considerable challenges in the analysis and processing of such data. To address these difficulties, computer vision algorithms have emerged as powerful tools, capable of automating repetitive and time-consuming tasks, enabling faster and more accurate processing. At the same time, the growing volume of data places pressure on storage and transmission capabilities, demanding efficient compression methods to minimise its size. In the literature, various approaches are found, primarily divided into two categories: lossy and lossless compression. While lossless methods ensure data integrity, they do not achieve compression rates as high as lossy algorithms. The latter, despite significantly reducing file sizes, introduces distortions that may compromise image quality, affecting the accuracy of automated systems. This dissertation focuses on two main challenges: first, evaluating the impact of image compression on the performance of biomedical computer vision systems, and second, improving compression efficiency without compromising the accuracy of these algorithms. To this end, detection and segmentation models, such as YOLOv8 and SAM, were used to analyse the effect of distortion caused by encoding on the localisation and segmentation of mitochondria in two datasets of electron microscopy images. To enhance model performance at higher compression levels, two methodologies were implemented. The first focuses on domain adaptation, fine-tuning the models to recognise and compensate for distortions introduced by compression, specifically in HEVC/H.265 and VVC/H.266 encoders. The second approach proposes contentaware encoder adaptation, allowing the assignment of different quality levels to selected regions of interest. This method aims to reduce storage and bandwidth requirements without significantly compromising the performance of deep learningbased models. Experimental results demonstrate that region-of-interest-based encoding strategies effectively reduce compression rates while maintaining model accuracy. In particular, the proposed methodologies allowed to achieve an average performance improvement of up to 23.70% for the same bpp range and a data size reduction of up to 74.96%. Additionally, a Pareto-based optimisation algorithm was proposed to determine the most suitable encoding configurations for different standards and models, ensuring a balance between compression efficiency and object detection performance.
- ADDITIVE MANUFACTURING FOR ANTENNA TECHNOLOGIESPublication . Carvalho, Saúl dos Santos; Caldeirinha, Rafael Ferreira da Silva; Reis, João Ricardo VitorinoThis dissertation explores the use of Additive Manufacturing (AM) technology, commonly known as Three-dimensional (3D) printing, for fabricating antennas, focusing on both static 3D and dynamic Four-dimensional (4D) printing techniques. It evaluates the cost-effectiveness and performance of these antennas compared to the ones fabricated using traditional methods (e.g. commercially available antennas). The study begins with the characterisation of dielectric properties of 3D printed materials through various extraction methods, which is crucial for accurate simulation and performance prediction. With this research several antennas were 3D printed and analysed, including pyramidal horn antennas, which were fully dielectric, with metallised polymers, with metal composites, and fully metallic, operating at K-Band. Additive manufacturing techniques, such as Laser Powder Bed Fusion (LPBF), were employed, with findings indicating that the resultant full metal horn antennas offered the best performance in terms of gain, impedance matching, and bandwidth. Additionally, the study examines 3D printed C-Band microstrip rectangular patch antennas. Results show that while 3D printed microstrip patch antennas can achieve reasonable efficiency and gain, they still lag behind traditional laminate-based antennas. A novel aspect of this research is the design of an X-Band pneumatic-deployable 4D petal horn antenna, which demonstrates potential for real-time adaptability through computational fluid dynamics and electromagnetic simulations. The dissertation concludes that 3D printing technology offers significant advantages for antenna fabrication, particularly in rapid prototyping and customisation. The emergence of 4D printing presents new possibilities for dynamic, adaptable antennas, though further research is needed to address material and fabrication challenges to fully harness its potential.
- Automotive 4D Radar Imaging with Field of ViewPublication . Jesus, Samuel Viegas Reigota de; Caldeirinha, Rafael Ferreira da Silva; Reis, João Ricardo VitorinoRadio Detection And Ranging (Radar) technology has been around for many decades. Initially developed for military purposes, radar technology has now grown into a larger set of applications. It is used in aviation, to detect other aircrafts and give accurate altitude readings, in marine navigation, to prevent collision with other ships and monitor ship movements in busy waters, in weather forecast, to monitor precipitation and wind, in factories, to enable manufacturing robots to perceive their environment and navigate/position themselves according to it, and even in health care, to monitor breathing and blood pressure, to name a few. In recent years, improvements in integrated circuitry and Radio Frequency (RF) electronics have made radar-on-chip possible, significantly reducing production costs and therefore enabling a wider adoption of radar technology, now commonly used in many civil applications. In the automotive industry for instance, Millimeter Wave (mmWave) radar sensors are being implemented in everyday vehicles for purposes such as Collision Warning System (CWS), Blind Spot Detection (BSD), Autonomous Cruise Control (ACC), Parking Assistance Systems (PAS) and many more, thus being integrated in systems such as Advanced Driver Assistance Systems (ADAS) and Autonomous Driving Systems (ADS). These systems comprise a suite of electronic automotive technologies designed to assist drivers in various driving scenarios, enhance safety, and improve the overall driving experience by providing real-time data through a combination of software algorithms and sensors, including cameras, ultrasonic sensors, Light Detection And Ranging (Lidar) and radar. Using real-time data from each component, ADAS and ADS can perceive the environment, plan a response, and control the vehicle’s mechanical systems to execute the intended action. As the market pushes for higher levels of vehicle autonomy, both ADAS and ADS are becoming increasingly more complex and sophisticated, requiring improvements in radar technology to meet the evolving demands of these advanced systems. Therefore, this dissertation presents the work on the development of a 4 Dimensions (4D) Multiple-Input-Multiple-Output (MIMO) automotive imaging radar with a 360◦ Field-of- View (FoV). After a brief description of the proposed architecture, using three mmWave 4D imaging radar sensors (AWR1843BOOST) by Texas Instruments (TI), disposed in a equilateral triangular prism shape, this dissertation presents the first results on the implementation of a real-time and high resolution radar sensor with a 360◦ FoV. To conclude the performance evaluation of the presented 360◦ radar, experimental results obtained in a controlled environment, i.e. inside an anechoic chamber, are presented to validate the proposed concept. A mmWave Compact Antenna Test Range (CATR) anechoic chamber was also designed and built in order to properly calibrate the radar. Successful target detection is achieved by multi-point point-cloud. The proposed radar architecture may be seen as an opportunity to augment and improve ADAS and ADS.
- Metodologia de análise da atividade microbiana por Laser SpeckleLaserPublication . Gameiro, Marco André de Araújo; Lopes, Nuno Manuel Lucas Vieira; Pinto, Rui Manuel da Fonseca
- LOSSY COMPRESSION OF BIOMEDICAL IMAGES FOR COMPUTER VISION ANALYSISPublication . Paulo, Edgar da Silva; Faria, Sérgio Manuel Maciel de; Távora, Luís Miguel de Oliveira Pegado de Noronha e; Thomaz, Lucas ArrabalThe exponential increase in medical and biomedical data acquisition is compelled by technological advances, namely in the imaging field. However, this exponential growth brings with it challenges in terms of processing capacity, transmission, and data storage. In response to this growing demand, increasingly efficient solutions have emerged, especially through computer vision for automatic image analysis and compression algorithms. This dissertation aims, on the one hand, to evaluate the performance of computer vision systems on previously compressed biomedical images. On the other hand, it increases the useful range of image variations, almost lossless and lossy, decreasing the impact of the change added by this method on the performance of computer vision algorithms in biomedical image analysis. In this sense, YOLO and Detectron2 are employed to evaluate the impact of coding distortion on their ability to detect mitochondria in electron microscopy images. The results of this study reveal that although the distortion introduced by compression affects their detection performance, it is negligible at lower compression ratios. Furthermore, two proposals are presented to improve the useful compression ratio, keeping the images characteristics that allow to perform the automatic detection of mitochondria. On the one hand, it is demonstrated that the proposed training methodology, which incorporates compressed versions of the original data during training, mitigates the impact of distortion on the performance of computer vision algorithms; on the other hand, allocating higher quality levels to regions of interest, compared to background elements, helps to sustain high performance at compression rates where computer vision algorithms typically start to lose effectiveness. These approaches allow the extension of the compression range with little impact on detection performance, thus contributing to the improvement of data processing, storage, and transmission in biomedical applications.
- Sistemas de localização de objetos em processos industriaisPublication . Batista, Alexandre Gaspar Vala; Ferreira, Lino Miguel Moreira; Gomes, Hugo Miguel CravoNum mundo industrializado onde o tempo de produção, a localização e rastreamento de objetos é de extrema importância, o presente projeto aborda o estudo detalhado e a implementação de sistemas de localização indoor de objetos apresentados na literatura e disponíveis no mercado. O objetivo é otimizar os tempos de produção em fábricas, identificando e minimizando os “tempos mortos” entre processos industriais. Para a realização deste tipo de sistema realizou-se um estudo do chão de fábrica, analisando o ambiente fabril, o tipo de máquinas, a composição de um molde, o percurso natural do fabrico de uma peça, a montagem do molde, e o comportamento dos operadores durante todo o processo. Feita a análise, selecionaram-se as melhores metodologias e equipamentos para a implementação de dois sistemas de rastreamento e localização de peças: ASW (Aquisition System with Wi-Fi) e ASL (Aquisition System with LoRa), baseados no microcontrolador ESP32, sendo o que o primeiro comunica diretamente por Wi-Fi para uma API que faz a filtragem dos dados para a base de dados e o segundo tem um módulo central (master) que recebe os dados dos restantes módulos de aquisição (slaves) via LoRa e envia via Wi-Fi os dados para a mesma API. Estes sistemas recolhem os dados de tags RFID lidos por leitores com antenas integradas. Conjuntamente com estes dois sistemas, implementou-se uma solução comercial da marca Zebra de forma a comparar confiabilidade dos sistemas construídos com uma solução comercial. Foi também desenvolvido um software que permitia associar as tags RFID à respetiva peça, visualizar todo o seu percurso durante o processo produtivo e localizar em tempo real em que zona/máquina se encontrava.
- Design and test of RF shielding for beam impedance reduction in CERN acceleratorsPublication . Santos, Miguel Valente dos; Fernandes, Telmo Rui Carvalhinho CunhaCERN, the European Organization for Nuclear Research, is one of the world’s largest laboratories for high-energy particle physics. At CERN, particle accelerators and detectors are used to study the basic constituents of matter. CERN’s flagship accelerator is the Large Hadron Collider (LHC), the most powerful particle accelerator built up to now. However, it would not work without its accelerator injector chain. This chain starts with LINAC4, followed by PSB, PS, and SPS, which inject into the LHC. Relatively new particle accelerators like the LHC were designed from scratch with a limited overall beam coupling impedance budget in mind, but this was not the case for the older accelerators at CERN, designed and built decades ago and originally intended for much lower beam intensities. Currently, one of the limiting factors to increase the beam intensities is instabilities caused by the beam coupling impedance of the older accelerators in the chain, such as the PS. The PS vacuum manifolds were identified as one source of instabilities due to a high beam coupling impedance. The current impedance contribution of the manifolds was simulated and measured. Several possible shielding solutions, aimed at reducing the beam coupling impedance, were studied and simulated, giving promising results. Routine RF measurements of other components of the accelerator were performed, either to complete the accelerator impedance contribution database or to assess whether or not the installed shielding is effective. During one of these measurements, it was found that a spare PS septa magnet had defective RF fingers, and the shielding was not effective.