Doctoral School

2024 EUA-CDE Annual Meeting
EUA: European University Association

"The role of data in shaping doctoral education", hosted by the UPC from 26 to 28 June 2024

Theses for defense agenda

Reading date: 14/06/2024

  • GÓMEZ DUEÑAS, SANTIAGO: Unraveling Hydrological Dynamics: Climate and Human Implications in the Magdalena River Streamflow and its Interaction with Ciénaga Grande de Santa Marta Wetland
    Author: GÓMEZ DUEÑAS, SANTIAGO
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN CIVIL ENGINEERING
    Department: (DECA)
    Mode: Normal
    Deposit date: 16/04/2024
    Reading date: 14/06/2024
    Reading time: 16:00
    Reading place: Sala Actes, edifici Vèrtex, Campus Nord, Gran Capitan S/N 08034 Barcelona, Spain
    Thesis director: BATEMAN PINZON, ALLEN | SANTOS GRANADOS, GERMÁN RICARDO
    Committee:
         PRESIDENT: SOLÉ, AURELIA
         SECRETARI: DE MEDINA IGLESIAS, VICENTE CÉSAR
         VOCAL: LA ROCCA, MICHELE
    Thesis abstract: This study offers a comprehensive understanding of the hydrological dynamics of the Magdalena River (MR) basin, located in Colombia. Multiple elements that affect streamflow were analyzed, such as climate-forcing drivers and human-induced ones, to understand the complex interactions that shape the region's hydrology.Firstly, the influence of many factors on the flow of water downstream of the Magdalena River was studied. The research identified El Niño southern oscillation (ENSO) episodes as crucial climate-forcing drivers and human-induced modifications such as reservoir evaporation. The complex nature of streamflow changes over time was highlighted by showing the variations in the average, volume, and maximum streamflow, as well as oscillations in evaporation and minimum streamflow, especially during positive ENSO episodes. These findings offer important insights into the changing hydrological regime of the MR basin, emphasizing the complex combination of elements that influence its flow patterns throughout time.Moreover, the study explored the hydrological connection between the MR and the Ciénaga Grande de Santa Marta (CGSM) wetland, revealing the interdependence of these two ecosystems. For this, the study explores the vulnerability of downstream habitats, especially wetlands, to changes in streamflow inputs by taking a broad approach that views the entire wetland as a unified unit. It identified crucial threshold ranges where the inflow from the Magdalena River to the CGSM becomes uncertain. This analysis highlights the urgent need to understand the interactions between water flow and wetland ecosystems and their significant impact. Furthermore, the present research utilizes Long Short-Term Memory (LSTM) neural network models to predict streamflow changes at the Calamar gauging station. The goal was to improve the precision of streamflow predictions by combining data from several gauging stations and reservoir evaporation records. Finally, this study can help enhance the comprehension of the intricate hydrological processes in the MR basin, revealing the interconnected effects of climate fluctuations, human actions, and ecosystem dynamics. In this context, this research sets the foundation for creating well-informed water resource management strategies in Colombia that protect wetland ecosystems' ecological health and adaptability in the face of ongoing environmental changes.
  • LÁZARO LUNA, LUCY LAURA: Strategic use of austenitic stainless steel in dissipative zones of eccentrically braced frames.
    Author: LÁZARO LUNA, LUCY LAURA
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN CONSTRUCTION ENGINEERING
    Department: (DECA)
    Mode: Normal
    Deposit date: 16/05/2024
    Reading date: 14/06/2024
    Reading time: 11:00
    Reading place: Sala de Tesines C1 002 - ETSECCCPB - Jordi Girona 1-3 Campus Nord - UPC
    Thesis director: CHACÓN FLORES, ROLANDO ANTONIO
    Committee:
         PRESIDENT: NASTRI, ELIDE
         SECRETARI: BARBU, LUCIA GRATIELA
         VOCAL: BOCK MONTERO, MARINA
    Thesis abstract: It is widely demonstrable that metals exhibit higher ductility and certain strain hardening beyond the yield strength. Carbon steel has been extensively used in the construction industry due to its several advantageous characteristics. This material exhibits a defined yield strength followed by a plateau and subsequently strain hardening. Attention has also been drawn to different alloys to address natural phenomena such as seismic events. These two aforementioned features are important in seismic design, and stainless steel is one of the novel materials being studied for this purpose, as it offers higher ductility and strain hardening.Based on experimental evaluations of all types of stainless steel, austenitic stainless steel has demonstrated high levels of ductility. Therefore, austenitic stainless steel EN 1.4307 is selected for this research. An extensive experimental program was developed to understand its behaviour in low-cycle fatigue, a main concern for seismic episodes in order to obtain the main characteristics and parameters needed to accurately model this behaviour.Cyclic strain hardening is the main feature of this evaluation. Parameters to describe the cyclic hardening and Bauschinger effect are calibrated using the numerical Chaboche model, which combines isotropic and kinematic hardening, two widely known approaches for the modelling of the material cyclic behaviour.The behaviour of structures against earthquakes can be characterised by low-cycle fatigue. Therefore, it is possible to capitalize on the cyclic properties found, namely strain hardening and ductility of austenitic stainless steel. The most well-known seismic-resistant frames are moment-resistant frames (MRFs), concentrically braced frames (CBFs), eccentrically braced frames (EBFs), and combinations thereof. All of these frames dissipate energy through various mechanisms of failure in specific zones. MRFs dissipate energy through bending moments in beams; CBFs do so via forces developed in braces; and EBFs dissipate energy through shear forces developed in strategically placed links.In this work. EBFs are analysed and designed using austenitic stainless steel EN 1.4307 in links as dissipative elements whereas, structural carbon steel is used for non-dissipative elements (i.e., beams, columns, and braces). The analysis reveals the importance of correctly selecting the set of cyclic parameters, as non-dissipative elements could achieve the plastic state before the link due to the excessive overstrength of the stainless steel.A correct value for overstrength is necessary to adopt to verify the capacity design of EBFs. Therefore, EBF designs are verified according to prEN1998 1-2:2022. However, this standard does not consider specific values for austenitic stainless steel, taking into account its overstrength more realistically.

Reading date: 17/06/2024

  • AKAZZIM, YOUNESS: Microwave Imaging for Brain Functional Monitoring
    Author: AKAZZIM, YOUNESS
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS
    Department: Department of Signal Theory and Communications (TSC)
    Mode: Article-based thesis
    Deposit date: 16/05/2024
    Reading date: 17/06/2024
    Reading time: 11:00
    Reading place: Defensa pública a l'Aula MERIT 010 edifici D5 del Depart. TSC secció Barcelona (Teoria Senyals i Comunicacions) de la UPC
    Thesis director: JOFRE ROCA, LUIS | EL MRABET, OTMAN
    Committee:
         PRESIDENT: SEGOVIA VARGAS, DANIEL
         SECRETARI: BROQUETAS IBARS, ANTONI
         VOCAL: BOLOMEY, JEAN CHARLES
    Thesis abstract: The use of microwave imaging techniques in medical applications has gained significant interest because of its non-ionizing character, low cost, and body penetrability. Different techniques and systems for microwave imaging have been successfully developed and tested for the diagnosis and monitoring of different parts of the human body to detect certain diseases by means of determining their complex permittivity distribution representing the electrical biological condition. This thesis proposes to open a new avenue adding to the previous biological condition imaging capabilities some trace of its biological activity. With this goal, a novel microwave technique oriented to locate and detect the low-frequency signals approaching the functional activity of a certain biological organ. These electrical signals, responsible for the different biological phenomena, are normally identified as action or membrane potential. Due to their low-frequency character (f ≃ 1 kHz), they stay mostly confined inside the human body and different kinds of contact electrodes are normally employed to measure them. In this work, we propose a novel technique to extract (from the inside of the human body) and wirelessly monitor these low-frequency signals (generated by a number of basic microorganisms as cells or bacteria mimicking the activity of the organ under study) based on the use of an illuminating microwave signal. Differently from the low-frequencies, the microwave signals are able to propagate inside (in and out) of the human body, being focused (with a Ultra-Wideband (UWB) - 0.5 to 2.5 GHz- multi-probe geometry) on a specific zone, and eventually becoming affected (modulated) by the low-frequency functional biological signals. Once extracted (de-modulated) from the interrogative microwave signal, the information of the action potential signal representing the functional activity, is spatially located inside the region of interest using a microwave differential imaging technique. In this work it has been specifically studied, the capability of monitoring localized action potential signals in the brain representing a Parkinson’s disease (PD), characterized by electrical signals generated in the subthalamic nucleus (STN) and the globus pallidus (GPi) with specific action potential patterns. Three main points have been developed: * Design of an optimized imaging geometry consisting of four (sequentially Tx and Rx) UWB Extended Gap Ridge Horn (EGRH) antennas disposed on two orthogonal sets.* Design of an UWB-Pulse Amplitude Modulation (PAM) monitoring system producing a nsec interrogation pulse * Modeling and validation of the UWB Microwave Functional Brain Activity Extraction for Parkinson’s Disease Monitoring concept.
  • CEDEÑO MATA, KRISTEL MICHELLE: Use of nanoparticles for energy and sensing applications
    Author: CEDEÑO MATA, KRISTEL MICHELLE
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN ELECTRONIC ENGINEERING
    Department: Department of Electronic Engineering (EEL)
    Mode: Article-based thesis
    Deposit date: 16/05/2024
    Reading date: 17/06/2024
    Reading time: 11:00
    Reading place: Defensa pública a la sala multimedia de l'edifici B3 del campus nord de la ETSETB
    Thesis director: BERMEJO BROTO, ALEXANDRA
    Committee:
         PRESIDENT: CABOT CODINA, ANDREU
         SECRETARI: RAMOS CASTRO, JUAN JOSE
         VOCAL: PLATIKANOV, STEFAN
    Thesis abstract: In this work, different nano, sub-micron, and microparticle materials have been embedded in various types of electrolytes, including ionic liquid gel polymer electrolytes (ILGPEs) and sodium chloride (NaCl), toenhance the performance of the filler-free fabricated capacitive devices for energy and sensing applications. The integration of these particles relies on their properties and beneficial role in devices for energy andsensing applications. In the energy field, this thesis explores the effect of incorporating SiO2 and Si@C sub-micron and nanoparticles into an ILGPE to enhance its energy storage capability. This work highlights the integration of these nanoparticles to improve the physicochemical characteristics of an ILGPE and, hence, its electrical performance, aiming to address the characteristic limitations of liquid electrolytes, such as leakage, or of GPEs, such as restricted ion conduction or high crystallinity. The composite ILGPEs exhibited capacitance improvements of 71% and 42%, for SiO2 and Si@C CGPEs, respectively, thereby demonstrating the beneficial role of these composites. Regarding the sensing field, this thesis explores two novel layers incorporating SiO2 particles into humidity and proximity sensing applications. Firstly, the viability of an ILGPE as a humidity-sensitive layer is assessed, and then different combinations of SiO2 nanoparticles and polyvinylpyrrolidone (PVP) are embedded into the ILGPE to enhance its humidity-sensing performance through increased sensitivity and reduced hysteresis. The results show that the SiO2 filler-ILGPEs achieve higher sensitivities and lower hysteresis. Secondly, a proximity sensor is developed using a dielectric layer formed from a mixture of SiO2 particles and NaCl. The fabricated proximity sensor has revealed a maximum capacitance sensitivity of 47.4 cm-1 and an operation range of 2-14 cm. Both layers exhibit effective potential for sensing applications and leverage the benefits of using environmentally friendly and cost-effective materials.Finally, in this thesis, a new surface modification of a polytetrafluoroethylene (PTFE) layer has been investigated, which allows for change from hydrophilic and hydrophobic characteristics. The proposedmethod can be helpful to optimize the electrospray deposition technique for particle coatings. This study contributes to enabling technology by improving the deposition processes and enhancing the coatings'functionality in energy storage and sensor applications. Summarising, this thesis has suggested the use of SiO2 nanoparticles as a good alternative for tailoringelectrolyte properties, defined a starting point in the use of SiO2 nanoparticles as a proximity-sensitive layer, and revealed novel CILGPEs that can be integrated into humidity sensing and energy
  • FERNÁNDEZ CAPÓN, LARA PILAR: Contribution to the Optimization of Natural Disasters Monitoring: an On-Demand Execution Strategy Approach
    Author: FERNÁNDEZ CAPÓN, LARA PILAR
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS
    Department: Department of Signal Theory and Communications (TSC)
    Mode: Normal
    Deposit date: 17/05/2024
    Reading date: 17/06/2024
    Reading time: 10:30
    Reading place: Defensa pública a la Sala de juntes del departament de TSC D4-012, Campus Nord (Barcelona)
    Thesis director: CAMPS CARMONA, ADRIANO JOSE | CALVERAS AUGE, ANA MARIA
    Committee:
         PRESIDENT: AGUADO AGELET, FERNANDO
         SECRETARI: GOMEZ MONTENEGRO, CARLOS
         VOCAL: TALONE, MARCO
    Thesis abstract: Natural disasters suppose a risk to life and assets, and can benefit from better early detection and monitoring systems. Current monitoring systems include in-situ instruments located along the Earth's land, such as the coast lines, or in the oceans. However, the monitoring needs are not met with the current solutions, due to the latency when retrieving the data. Other sensors are located in land, the latency may be negligible provided they are connected to terrestrial networks, but the warning is given when the disaster is already happening in populated areas. Aside from in-situ instruments, also satellite Earth Observation (EO) payloads monitor the extent and risk areas affected by natural disasters. These payloads generate large amounts of data, and it is often impossible to download it through a Ground Station, imposing duty cycle limitations in the executions.The appearance of the 5G paradigm, and the definition of the Non-Terrestrial Networks, has boosted space-to-Earth communications using Internet of Things (IoT) technologies. These systems can contribute to natural disasters early detection and monitoring by placing IoT ground nodes on the Earth's surface, since they are inexpensive to deploy, and can contain different types of sensors depending on the variables to be monitored. Moreover, the ground nodes can provide constant readings, and forward them to a satellite if an anomalous reading is detected, to wake-up the EO payload to perform a continuous monitoring. This paradigm is one of the main contribution of this thesis, called the On-Demand Satellite Payload Execution strategy.The feasibility of this monitoring paradigm is first analyzed by presenting the monitoring needs, defining the requirements in terms of density of ground nodes, update frequency of the measurements, and types of sensors required. After that, a more in depth work related to IoT space-to-Earth communications is conducted, assuming that the Long Range (LoRa) modulation is used. The physical layer is first studied by computing a link budget, considering different payload architectures, assessing the communication limitations for each of them. Then, the effect that ionosphere scintillation has on the overall throughput is evaluated by a set of tests. Following, the Media Access Control (MAC) layer is studied by identifying the optimum protocols for IoT space-to-Earth communications. Then, the maximum density of ground nodes for each protocol, and for different antenna footprint sizes is computed, based on the monitoring requirements defined previously for natural disasters monitoring. Moreover, a set of proof-of-concept experiments are conducted to simulate the scenarios identified in the MAC layer theoretical study. This encompasses the comparison of two different protocols, identifying the limitations of each one. Finally, the design and software development of a Software Defined Radio (SDR)-based LoRa payload is presented. Another contribution of this thesis is related to the antenna design for small satellites and CubeSat payloads. Starting with two different antennas used for satellite communications. The first one being an IoT LoRa patch antenna for the RITA payload. Then, the COMET B2 Probe Inter-Satellite Link (ISL) antenna is presented, this study comprises first a sensitivity study based on simulations on the optimum antenna geometry. Then, an additional analysis is done simulating the optimum position of the final Commercial Off The Shelf (COTS) antenna used for the mission. Afterwards, the requirements definition, theoretical design, simulations, prototyping, and flight model testing and results are presented for the 3Cat-4 L-Band Helix Antenna and for the FSSCat Nadir Antenna. Both of this antenna are for a Global Navigation Satellite Systems Reflectometer (GNSS-R) and Microwave Radiometer (MWR) payload. Finally, a sensitivity analysis of the optimal positioning the L5 Nadir Antenna, for a GNSS-R payload is presented.

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I.M: International Mention, I.D.: Industrial Doctorate, G.C.: Generalitat de Catalunya