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: 26/06/2024

  • ASTUDILLO GUTIERREZ, CARLOS SALVADOR: Posidonia oceanica: A Perspective From Coastal Protection
    Author: ASTUDILLO GUTIERREZ, CARLOS SALVADOR
    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 MARINE SCIENCES
    Department: (DECA)
    Mode: Article-based thesis
    Deposit date: 23/04/2024
    Reading date: 26/06/2024
    Reading time: 11:00
    Reading place: Edifici C1 Aula 002, ETSECCPB, Campus nord, Universitat Politècnica de Catalunya
    Thesis director: GRACIA GARCIA, VICENTE | CACERES RABIONET, IVAN
    Committee:
         PRESIDENT: COLOMER FELIU, JORDI
         SECRETARI: GIRONELLA I COBOS, FRANCESC XAVIER
         VOCAL: FERNÁNDEZ MORA, MARIA DE LOS ANGELES
    Thesis abstract: Over the decades, the global coastlines have been a key indicator of the development of actual societies. However, the cost of this growth has resulted in the depredation of natural environments. The increased frequency of storms, rising temperatures or rising sea levels are clear symptoms that the environment is responding to the increased pressure that the coasts have been subjected to. In recent years, the degradation of coastal habitats has accelerated, indicating that traditional engineering solutions alone will not be able to solve the problem in the long term. IThis approach enables nature to be reintroduced as a potential element capable of confronting and counteracting the adverse changes that the coastal landscape is undergoing. In order to achieve this goal, it is essential to conduct a comprehensive analysis of the natural elements that comprise the coastline, with a particular focus on identifying strategies that enhance environmental stability. This study aims to gain a deeper understanding of the impact of Posidonia oceanica seagrass meadows on the coastline, both in their submerged and emerged states.A novel experiment was conducted in the experimental flume CIEM of the LIM/UPC Barcelona. The objective was to evaluate the protective effect of submerged meadows against irregular erosive waves on a sandy beach with a 1:15 slope. A real meadow model was used with plastic substitutes carefully selected to accurately reflect the dimensions, movements and habitats of a real Posidonia oceanica plant. The submergence ratio and density of the meadow were kept constant. The work has focused on measuring the attenuation of wave height, changes in velocity, involvement in sediment transport and shore erosion. The results showed a persistent decrease in wave height from the area behind the meadow to the breaker zone, which was directly correlated with meadow length and wave energy. Consequently, there was less shoreline erosion as a function of wave height attenuation in cases where meadow was present, and even less when the meadow was longer. Behind the longer meadow, there was a notable change in velocity, resulting in an imbalance of peak velocities. This included a decrease in negative peak velocities and an increase in positive peak velocities. This resulted in an increase in the skewness value of the velocity in this area. The orbital velocities exhibited a decrease only for the long meadow case, which contributed to a decrease in sediment transport volume and the formation of a breaker bar closer to the coast.The emerged part of the meadows was evaluated through field work, analysing the accumulations on the shoreline. Several routes were taken along the southern Catalan coast in order to identify the most frequent accumulation sectors associated with the position of the submerged meadow. Areas with seagrass meadows were identified at depths greater than 5 m, and it was found that these areas exhibited a low frequency of occurrence of banquette events. Information on the management of the accumulations was obtained through interviews with the relevant personnel in each coastal municipality. The aim was to ascertain the manner in which the banquette is dealt with during periods of high tourism demand. Furthermore, this work presents a characterisation of parameters such as penetration resistance and permeability of the accumulations. Additionally, a methodology based on thermal oxidation has been presented to accurately quantify the amount of sediment that can accumulate in the banquettes. The results indicate that the banquettes situated in close proximity to the shoreline accumulated less sediment than those positioned at a greater distance from the coast.

Reading date: 27/06/2024

  • CID ESCOBAR, DANIELA: Methodologies for improving groundwater access in rural areas: "Towards the improvement of human development in low and middle-income countries
    Author: CID ESCOBAR, DANIELA
    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 GEOTECHNICAL ENGINEERING
    Department: (DECA)
    Mode: Normal
    Deposit date: 10/05/2024
    Reading date: 27/06/2024
    Reading time: 11:00
    Reading place: ETSECCPB. UPC, Campus Nord Building D2. Classroom: 216 C/Jordi Girona, 1-3 08034 Barcelona
    Thesis director: FOLCH SANCHO, ALBERT | SANCHEZ VILA, FRANCISCO JAVIER
    Committee:
         PRESIDENT: SAWYER, AUDREY
         SECRETARI: FERNANDEZ GARCIA, DANIEL
         VOCAL NO PRESENCIAL: PALTAN LOPEZ, HOMERO
    Thesis abstract: Sustainable groundwater management in rural areas presents multifaceted challenges stemming from hydrogeological complexities, socio-economic disparities, and governance issues. This thesis aims to provide quantitative tools for addressing some of the groundwater access problems in rural areas of low- and middle-income countries by promoting an interdisciplinary approach and the understanding of the expertise of each discipline. The first part of the thesis focuses on developing a comprehensive methodology to assess individual user risk of groundwater shortage. After a preliminary multifactorial analysis incorporating a range of variables from technical to societal, it was found that most of the overall risk of water shortage for an individual household could be attributed to three factors: Proximity, specified as the distance to the closest supply well. Availability of good quality water in the wells, and Sustainability. The factors are mapped onto indicators in the range of [0 - 1] and then represented in a Geographical Information System based on the partition of the entire spatial domain. The three indicators are then combined in a final index based on the product of the three factors, thus mapping time-dependent overall risk and allowing the assessment of temporal risk-evolution scenarios. The methodology is applied to Kwale County, Kenya, where community handpumps and groundwater points comprise the main water supply system. Apart from mapping the present situation, the methodology is also used to assess the impact on hypothetical scenarios. The second part of the thesis extends the analysis to four Eastern African countries, as an attempt to address the complexity and heterogeneity that characterise the human-groundwater interaction in rural water supply systems, we propose a multivariate approach that combines many different variables, such as water point functionality and groundwater quality characteristics, social and economic parameters, such as water point maintenance, finance, and governance system. The combination of variables of very different types and ranges of values is better suited using Multiple Factor Analysis (MFA) as a way to determine formally the main variables that affect water access and the relationship amongst them. The methodology was applied in four different countries of Eastern Africa supplied mainly with hand-pumps. The analysis was performed on datasets collected during a waterpoint census by the UPGro "Hidden Crises" and "Grow for Good" Projects from Kenya, Uganda, Malawi, and Ethiopia. The results of the analysis show the existence of common trends, indicating that water access in Eastern African rural areas can be described mainly by three main components: one representing the hydrogeological environment, a second comprising water point management agreements, and a third component linked to the sustainable functionality of hand-pumps. Finally, the thesis explores into household water usage patterns and the impact of groundwater salinity on (ground)water source selection. A mixed-methods approach combining household surveys and physicochemical analysis of groundwater was employed across Kwale County during the dry season. Co-occurrence matrices were used to analyse usage patterns, while logistic regression models were used to understand the influence of salinity, demographic and socio-economic factors on water source preferences. Despite limited changes in drinking water sources between wet and dry seasons, significant shifts occur in non-drinking water uses, demonstrating the community's adaptability in utilizing available water sources. Factors such as taste, safety, and proximity play significant roles in households' decisions regarding their main drinking water source. Moreover, the study highlights the significant impact of groundwater salinity levels on usage patterns, identifying threshold salinity levels beyond which households are less likely to choose certain water sources.

Reading date: 28/06/2024

  • GASPARINO FERREIRA DA SILVA, LUCAS: High-performance low-dissipation algorithms for simulation of turbulent compressible flows
    Author: GASPARINO FERREIRA DA SILVA, LUCAS
    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 AEROSPACE SCIENCE AND TECHNOLOGY
    Department: Department of Physics (FIS)
    Mode: Normal
    Deposit date: 03/04/2024
    Reading date: 28/06/2024
    Reading time: 11:00
    Reading place: BSC Auditorium, Planta -1, Plaça Eusebi Güell 1-3, Barcelona
    Thesis director: LEHMKUHL BARBA, ORIOL | MIRA MARTÍNEZ, DANIEL
    Committee:
         PRESIDENT: RUBIO CALZADO, GONZALO
         SECRETARI: JOFRE CRUANYES, LLUÍS
         VOCAL: COLOMBO, ALESSANDRO
    Thesis abstract: Motivated by recent advances in computational technology aiming at exascale capabilities, which implies a need for applicationscapable of taking advantage of these new supercomputing architectures, this work will present two algorithms aimed at implementing an efficient and low-dissipation algorithm focused on LESand DNS of turbulent compressible flows.The basis for the algorithms is the Continuous Galerkin method applied to elements whose nodes and quadrature points areformed from the Gauss-Lobatto-Legendre roots, resulting in a SpectralElements Method. Throughout this work, it will be evidenced that this formulation leads to highly efficient kernels for discretizingthe convective and diffusive terms of the compressible Navier-Stokes equations, with the added benefit that the order of the scheme is coupled with the order of the shape functionpolynomials employed by the elements themselves, significantly simplifying the process of increasing the order of the scheme.To achieve a stable Total Variational Diminishing algorithm, the \acrshort{sem} scheme will be paired with an EntropyViscosity-based stabilization model and a suitable splitting of the nonlinear convective terms will be employed to eliminate aliasing issues that occur in the \acrshort{sem} formulation.This spatial discretization is then coupled with both an explicit and a semi-implicit scheme to account for the temporal nature ofthe flow equations. The explicit version of the algorithm is expected to be simple and efficient per time step, but due to its \acrshort{cfl} condition limitation, the semi-implicit version is alsoproposed to allow for better overall performance incases where the time-step becomes overly limited, such as in wall-bounded flows.Considering the focus on producing a \acrshort{cfd} application towards the exascale future, an important aspect of this work isthat both algorithms are proposed with a full \acrshort{gpu}implementation in mind: the use of accelerators is expected to be a key aspect of future supercomputing architectures, and thus itis important to design these algorithms with this in mind.Examples detailing the performance of both algorithms will be presented both in the case of a single device and when distributedarchitectures using multiple devices are employed.

Reading date: 01/07/2024

  • ALZATE MEJIA, NESTOR: Modelado de la incertidumbre humana en la asignación de recursos para redes de comunicaciones
    Author: ALZATE MEJIA, NESTOR
    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 COMPUTER ARCHITECTURE
    Department: (DAC)
    Mode: Normal
    Deposit date: 03/06/2024
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: DE ALMEIDA AMAZONAS, JOSÉ ROBERTO | PERELLO MUNTAN, JORDI
    Committee:
         PRESIDENT: MARZO LAZARO, JOSE LUIS
         SECRETARI: BARLET ROS, PERE
         VOCAL: NIN GUERRERO, JORDI
    Thesis abstract: This research addresses resource allocation in communication networks, with emphasis on the impact of human uncertainty on the performance of these networks, especially those using advanced technologies. The central hypothesis of this thesis is that variations in human behavior influence the operational efficiency of communication networks. To validate this hypothesis, a methodology has been designed that includes an exhaustive review of the specialized literature, complemented with a rigorous qualitative and quantitative analysis in simulated scenarios.In this context, a specific case study is investigated: the use of mobile applications for rented vehicles with driver, such as Uber and Cabify, operating in a network slice of a 5G network. These applications, installed on mobile devices, facilitate the connection between users and drivers, showing the availability of vehicles in real time. The process begins when a user selects an origin and destination point in the app, which proposes an optimal route. However, the driver can modify the proposed route without penalty, introducing uncertainty that can negatively affect network performance.In the simulations, special attention is paid to the Call Drop Rate (CDR) as a function of possible failures during the handover process. The simulations are developed in multiple stages: initially in a minimum scenario, designed to verify the influence of uncertainty on network performance. In the second stage, the model is evaluated in the Simulation of Urban Mobility (SUMO) simulator, which brings more realism to the vehicular environment. This simulator is integrated with the Artery-C framework, which incorporates elements related to 5G technology. In the final phase, data from the InTAS scenario, which models detailed information of the city of Ingolstadt, is used, providing a robust test environment for model validation.The findings show the relevance of developing methodologies that optimize resource allocation and improve network performance, aligned with operators' strategic objectives. This approach represents a promising way to increase efficiency and effectiveness in the implementation of technological solutions in dynamic and complex environments.The main objective of this research is to develop and evaluate a model that captures human uncertainty from multiple perspectives, adopting an interdisciplinary approach. The results indicate that human uncertainty significantly affects the performance of communication networks. Through an interdisciplinary approach, an innovative model has been designed that integrates sociological, psychological and computational aspects, capturing human uncertainty in advanced technology contexts. The adaptability and effectiveness of the model have been corroborated using advanced computational tools.This study contributes to the field of resource allocation in communication networks, demonstrating the importance of adopting adaptive strategies. For future research, it is proposed to extend the model to analyze different network slices, considering unique characteristics and constraints imposed by service providers. This would include the evaluation of resource seasonality to improve the elasticity and responsiveness of the model. In addition, it is suggested to develop an innovative method for dynamic resource allocation that incorporates human uncertainty, allowing adaptive decisions in real time. These approaches would promote more effective management and optimization of network resources in various contexts and temporalities.
  • IRAOLA DE ACEVEDO, EDUARDO: Predictive simulation, active diagnosis and dynamic monitoring for tritium processing systems
    Author: IRAOLA DE ACEVEDO, EDUARDO
    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 NUCLEAR AND IONISING RADIATION ENGINEERING
    Department: Department of Physics (FIS)
    Mode: Normal
    Deposit date: 05/06/2024
    Reading date: 01/07/2024
    Reading time: 11:00
    Reading place: Defensa pública a la LS.12 de l'ETSEIB (campus sud-Avda. Diagonal, 647)
    Thesis director: BATET MIRACLE, LLUIS
    Committee:
         PRESIDENT: PAPATHANASIOU, MARIA
         SECRETARI: SERRA PRAT, MARIA
         VOCAL: MARTELLI, DANIELE
    Thesis abstract: Nuclear fusion has been under development for years, showing consistent advancements toward becoming a clean and efficient energy source. However, significant challenges persist in this field, with tritium handling being a major concern. Tritium, a radioactive form of hydrogen used as fuel for fusion, presents unique issues due to its ability to penetrate walls and interact with water and organic compounds.In ITER, where tritium will be used on a large scale (reaching quantities in the order of kilograms), ensuring plant safety is critical. The plant must periodically halt operations to consolidate all process streams for tritium accounting, a time-consuming process that can last hours. This practice is impractical for future industrial fusion plants aspiring for economic feasibility, especially considering the pulsating nature of tokamak burn phases.This thesis proposes a dynamic monitoring framework to address these challenges and improve static tritium accounting. Leveraging first-principle simulation models and data-driven methodologies such as fault detection and time series forecasting, the framework aims to provide continuous, reliable tritium inventory updates. The framework's effectiveness is verified using the Tennessee Eastman process, a process engineering virtual plant, and validated on a representative tritium processing system: the Tokamak Exhaust Processing system.

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