Doctoral School

Reading date: 22/05/2026

• BRUERA MÉNDEZ, RENZO: Stable solutions to some local and nonlocal elliptic problems
  
  Author: BRUERA MÉNDEZ, RENZO
  Programme: DOCTORAL DEGREE IN APPLIED MATHEMATICS
  Department: School of Mathematics and Statistics (FME)
  Mode: Normal
  Deposit date: 28/04/2026
  Reading date: 22/05/2026
  Reading time: 16:30
  Reading place: Sala d'Actes de l'FME, Edifici U, Campus SudEnllaç videoconferència: https://meet.google.com/faf-egfq-rsq
  Thesis director: CABRE VILAGUT, XAVIER
  Thesis abstract: This thesis concerns stable solutions to some variational elliptic partial differential and integro-differential equations. Stable solutions are critical points of the energy functional associated to the equation at which the second variation of the energy is nonnegative. That is to say, essentially, they are local minimizers of the energy functional. As such, stable solutions usually constitute the observed state of many physical systems. From a mathematical perspective, they enjoy interesting properties that are not shared by general solutions.The thesis is divided into two parts.In the first part, we address the issue of the regularity of stable solutions to a class of semilinear elliptic reaction-diffusion equations with singular nonlinearities (i.e., nonlinearities that are unbounded). They are usually called MEMS-type equations. Our main contribution is to show that stable solutions to such problems are smooth up to the optimal dimension n = 6 whenever the nonlinearity f satisfies a convexity assumption. Moreover, we prove, for the first time in the literature, interior a priori estimates for solutions to these problems that hold regardless of the boundary condition satisfied by the solution. We also give global estimates for the Dirichlet problem with vanishing boundary condition.In the second part, we first study the existence of periodic constant nonlocal anisotropic mean curvature surfaces of revolution, which we call anisotropic nonlocal Delaunay surfaces. We show that such surfaces arise as minimizers of a periodic version of the anisotropic nonlocal perimeter, and we also construct them as perturbations of straight cylinders in the plane—we call these near-cylinders. Finally, in the last chapter, we characterize the stability of these near-cylinders in the homogeneous and isotropic case, and we show that the only minimizers in R2 of the periodic nonlocal perimeter that are close to straight cylinders are, possibly, straight cylinders themselves.
  

• OLIVA FELIPE, LUIS JAVIER: Artificial Virtuous Agents in water management scenarios
  
  Author: OLIVA FELIPE, LUIS JAVIER
  Programme: DOCTORAL DEGREE IN ARTIFICIAL INTELLIGENCE
  Department: Department of Computer Science (CS)
  Mode: Normal
  Deposit date: 24/03/2026
  Reading date: 22/05/2026
  Reading time: 11:00
  Reading place: FIB Sala d'actes Manuel Martí Recober B6-planta 0Campus Nord
  Thesis director: CORTÉS GARCÍA, CLAUDIO ULISES | CORTÉS MARTÍNEZ, ATIA
  Thesis abstract: As human populations continue to grow, resource consumption rises inexorably, leading to eventual depletion, as stated by Malthus and especially by Hardin's Tragedy of the commons. To maintain resource sustainability, coordinating the collective action of those who seek benefit from consuming that resource is necessary. However, there is a small part of the whole set of participants which may act selfishly and ignore any norm or social convention that constrains overconsumption or regulates the way it is consumed. This occurs because collective action, as explained by Olson in Logics of Collective Action (Olson, 1971), can face two different social dilemmas: The prisoner's dilemma and the free-rider dilemma. The former explains how individual choice leads to a local optimal (i.e., personal benefit) but at the cost of a bad global result (i.e., common good gets depleted and, finally, nobody benefits any longer). The latter explains how free-riders, i.e., selfish or rogue agents, can burden the maintenance of the common good as the group of consumers grow since avoiding paying the cost to preserve it may not be perceived (e.g., reducing the consumption rate or paying taxes) while the common good is still provided and consumers cannot be excluded.This thesis explores the use of virtue ethics in the decision-making process of agents. Virtues are usually associated with moral excellence or a conformity to a standard of right. In our case, the goal is to represent, to some extent, virtuosity according to classic ethics, concretely, Plato’s and Aristotle’s ethical schools of thought. In Plato and Aristotle's writings, virtues are usually defined as character traits that drive how an agent should behave in the world. In both approaches the goal of the agent is to act in the right way, according to virtues, to achieve a state of eudaimonia (having a plentiful and fulfilling life). We understand that the rightness of an agent is not only determined by what they want to do but also by how they balance their actions to perform them (i.e., acting according to your values and virtues). We would like to analyse how to model values and virtues to represent, to some extend, a Platonic and Eudaimonistic form of virtue ethics. Our model of values and virtues uses Swanton’s target-centered approach to virtue ethics.In both ethical approaches, it is not only necessary to consider the individual but also the society these individuals live within. These societies should foster their individuals to be virtuous. Since values and virtues are considered incommensurable, we decided to focus on a specific context to which is water consumption. For this reason, the thesis is divided into two main chapters: one focusing on the individual consumption of fresh water in households in a mid-size Mediterranean town, and another at the societal level, which uses a model of industrial wastewater management in the besos river basin, whose catchment is located in Barcelona, and is a typical example of a Mediterranean complex catchment. The catchment area is one of the most populated catchments in Catalonia, having more than 2M people connected, whose working population is mainly occupied in industrial activities and the services sector. These industries are of various activities with an important presence of the chemical, metallurgical, plastics, textile, paper and food sectors. Each of these sectors has different needs with regard to water usage.We raise the hypothesis that artificial virtue agents may perform better than classic utilitarian agents with regards to common-pool resource sustainable consumption. We think that both approaches (Platonic and Aristotelian) are not better to each other but depending on the context it is possible that significant differences become relevant. That is, both are two different ways to act rightfully.
  

• PAVO FERNÁNDEZ, EVA: Coastal dynamics and resilience in the low-engineered coast of Mozambique
  
  Author: PAVO FERNÁNDEZ, EVA
  Programme: DOCTORAL DEGREE IN MARINE SCIENCES
  Department: Department of Civil and Environmental Engineering (DECA)
  Mode: Normal
  Deposit date: 23/03/2026
  Reading date: 22/05/2026
  Reading time: 11:30
  Reading place: ETSETB Sala TeleensenyamentEdifici B3 - Ricardo Valle Sala 103 Planta 1Campus Nord Jordi Girona, 1-308034 Barcelona
  Thesis director: GRACIA GARCIA, VICENTE | GRIFOLL COLLS, MANUEL
  Thesis abstract: Coastal areas are crucial and sensitive environments that are increasingly at risk due to climate change. Yet, a significant research gap persists in integrating the various scales of coastal analysis, from long-term geomorphological settings to short-term (extreme events), in regions with limited information, as is the case of Mozambique.This thesis tackles this gap by utilizing a comprehensive, multiscale approach to study the dynamic and under-researched coastline of Mozambique. The region serves as a compelling case study, presenting a diverse geomorphology and high vulnerability to tropical cyclones within a data-scarce context. The research uses high-resolution satellite imagery, hydrodynamic data, geomorphological mapping, and process-based numerical modelling to provide a holistic assessment of coastal processes.By bridging the scales between remote sensing, geomorphological context, and process-based modelling, this thesis aims to advance the predictive understanding of coastal change in Mozambique. The outcomes provide a scientific foundation for informed coastal management, support coastal resilience, and offer a transferable template for studying other vulnerable, data-scarce coastlines globally.
  

• SÁNCHEZ-ARCILLA ROSANAS, AGUSTÍN: PREDICTIVE MAINTENANCE OF HARBOUR STRUCTURES AND COASTAL SYSTEMS
  
  Author: SÁNCHEZ-ARCILLA ROSANAS, AGUSTÍN
  Programme: DOCTORAL DEGREE IN MARINE SCIENCES
  Department: Department of Civil and Environmental Engineering (DECA)
  Mode: Article-based thesis
  Deposit date: 26/03/2026
  Reading date: 22/05/2026
  Reading time: 11:30
  Reading place: Place: ETSECCPBUPC, Campus NordBuilding C1. Classroom: 002C/Jordi Girona, 1-308034 Barcelona
  Thesis director: SANCHEZ-ARCILLA CONEJO, AGUSTIN | ALTOMARE, CORRADO
  Thesis abstract: This PhD thesis contributes to the understanding and maintenance of Mediterranean and Atlantic coastal systems under accelerating climatic and human pressures. For that purpose a new methodology has been developed, combining beach morphodynamics, adaptation pathways with tipping points, and considering relevant institutional barriers to coastal restoration. The developed methodology focuses on combining process-based coastal engineering, machine learning techniques and adaptation governance frameworks to get a systemic approach for an adaptation based on restoration.Such an approach considers the barriers to coastal restoration, along with the necessary “enablers” to overcome them, always supported by coastal engineering techniques, process-based models, predictions using machine learning, and adaptation governance frameworks. In this way, a systemic approach to coastal dynamics is obtained, making it possible to make decisions based on predicting and analyzing how a typical beach may evolve under future climate scenarios and what the most appropriate responses are.Mediterranean beaches are highly dynamic albeit constrained systems often with scarcity of sediments, encroachment of urban areas, and limited accommodation space. These factors, together with growing human pressures, are expected to increase the risk of erosion and reduce the resilience of the considered beaches. The first contribution of this thesis is developed in the paper “Coastal Adaptation Pathways and Tipping Points for Typical Mediterranean Beaches under Future Scenarios”. This paper identifies adaptation tipping points for typical Mediterranean beach types, subject to 50- and 100-year storms, combined with the projected sea-level rise. The research quantifies when conventional measures such as shoreface nourishment, dune reinforcement, or structural protection are bound to lose effectiveness, suggesting the application of adaptation pathways. The results present a time-sequenced approach for proactive decisions, enabling a flexible coastal management and avoiding reactive protection with high impacts and carbon footprint.Based on the improved systemic understanding of beach systems, the second contribution of the thesis is presented in the article “Morphodynamic Predictions Based on Machine Learning: Performance and Limits for Pocket Beaches near the Bilbao Port.” This work analyzes the use of artificial intelligence (machine learning or ML) in coastal morphodynamics. Using high-resolution datasets associated with pocket beaches affected by port interventions, the predictive performance of machine learning models has been compared with conventional methodologies that apply process-based models or traditional statistical techniques. The results show that ML-based models exhibit a high short- and medium-term predictive capacity for capturing complex coastal responses, although their performance is more limited under extrapolated or extreme conditions. This study contributes to integrating coastal engineering with artificial intelligence, providing scalable tools for early warning systems and adaptive coastal monitoring.The cornerstone for sustainable coastal restoration is presented in the third contribution of the Thesis, developed in the article “Coastal Restoration Agreements under Climate Change: Barriers and Enablers.” This work links the analysis of physical processes with governance mechanisms to address the adaptation deficit present in coastal areas. Even when the technical or physical adaptation pathways are known, their implementation faces institutional fragmentation, regulatory rigidity, and social perception. Through an analysis based on application cases, this research identifies the main barriers and enabling factors for coastal restoration under climate uncertainty.
  

Reading date: 27/05/2026

• RUIZ CARREGAL, GERARD: High-Resolution Drone-Based Repeat-pass SAR Interferometry for 3D displacement estimation
  
  Author: RUIZ CARREGAL, GERARD
  Programme: DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS
  Department: Department of Signal Theory and Communications (TSC)
  Mode: Article-based thesis
  Deposit date: 15/04/2026
  Reading date: 27/05/2026
  Reading time: 11:00
  Reading place: Sala D4 012, UPC Campus Nord.
  Thesis director: LOPEZ MARTINEZ, CARLOS | IGLESIAS GONZÁLEZ, RUBÉN | LORT CUENCA, MARC
  Thesis abstract: The precise characterization of ground deformation processes is essential for risk assessment and early-warning applications, since displacement is often a precursor to catastrophic failures. Over the past two decades, Synthetic Aperture Radar (SAR) and Multi-Temporal Differential SAR Interferometry (MT-DInSAR) have enabled millimetric displacement estimation over wide areas with dense spatial sampling. Within this context, satellite-based SAR offers regular, long-term global coverage, while Ground-Based SAR (GBSAR) provides near real-time monitoring, enabling the observation of localized rapid deformation processes. Despite these strengths, both systems present inherent limitations. Satellite SAR cannot capture rapid displacements due to multi-day revisit intervals and provides no sensitivity to displacement along the North-South (NS) direction due to its near-polar orbits. GBSAR provides excellent temporal resolution, but its deployment is limited in inaccessible areas, and its fixed geometry often leads to displacement underestimation.Airborne SAR systems mitigate several of these limitations by offering controlled revisit times and multi-view imaging, allowing the retrieval of the three-dimensional (3D) displacement vector. In this context, multirotor drones have emerged as a cost-effective and adaptable platform for airborne SAR. Drone-borne SAR inherits airborne challenges related to platform motion and navigation uncertainties, together with additional constraints such as payload limitations, and requires the adaptation of MT-DInSAR algorithms to low-altitude platforms and non-regular revisit times.The objective of this dissertation is to demonstrate the capability of drone-based SAR systems to estimate ground displacement time-series using multi-temporal interferometric stacks in real operational scenarios. To this end, the thesis develops an end-to-end framework encompassing sensor development, interferometric processing, and MT-DInSAR methodologies. A Ku-band dual-channel Frequency-Modulated Continuous-Wave (FMCW) radar is developed and integrated into a multirotor platform. An interferometric processing chain is further proposed to generate phase-calibrated repeat-pass interferograms, combining Digital Elevation Model (DEM) refinement from single-pass interferometry with a dedicated coregistration strategy, where the MTCD-MSQ algorithm is introduced as a new coregistration approach designed for high-frequency airborne acquisitions. Furthermore, two complementary MT-DInSAR workflows are proposed to address distinct deformation regimes. SD-MT-DInSAR retrieves cumulative displacement time-series when interferometric coherence is preserved between consecutive acquisitions, while SDVEL-MT-DInSAR exploits the flexibility of drones to perform repeated intra-day flights to estimate displacement velocity time-series in rapidly deforming areas, where decorrelation occurs in a few hours. Finally, the thesis employs multi-geometry acquisitions to retrieve the full 3D displacement vector.The framework is validated in controlled experiments with Corner Reflectors (CR) and in real operational conditions over an active open-pit mine, demonstrating submillimetric sensitivity, meter-scale displacement monitoring over several days, and 3D displacement retrieval in complex scenarios.The dissertation confirms that drone-based SAR is a reliable deformation monitoring tool that complements satellite and GBSAR systems, opening new opportunities in geotechnics, mining, and natural hazard assessment.