Public display of deposited theses

DOCTORAL DEGREE IN AEROSPACE SCIENCE AND TECHNOLOGY

• SURAPANENI, ANURAG: Multi-regime combustion modelling in high-fidelity numerical simulations of reacting flows
  
  Author: SURAPANENI, ANURAG
  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: 01/10/2024
  Deposit END date: 14/10/2024
  Thesis director: MIRA MARTÍNEZ, DANIEL
  Committee:
       PRESIDENT: DOMINGO, PASCALE
       SECRETARI: ESCOFET MARTÍN, DAVID
       VOCAL: GRENGA, TEMISTOCLE
  Thesis abstract: The quest to reduce carbon-based emissions has led to the use of alternative fuels and combustion systems. The aviation industry presents unique challenges due to the need for high-energy fuels, with e-fuels and hydrogen among the early candidates to facilitate net-carbon neutrality. To this end, LES simulations of turbulent reacting flows have emerged as key design and analysis tools. Capturing the complexities of realistic burner configurations poses a multi-scale, multi-physics problem. The inherent flow complexities and multi-fuel systems often result in practical systems operating in multi-regime combustion, a consequence of mixture inhomogeneity that promotes a complex response of burning rates and pollutant formation. It is therefore fundamental that the models reacting flows capture this complex response. Combustion can be solved using a variety of methods that balance generality and computational cost. Finite rate chemistry methods are the most general but also prohibitively expensive, while manifold-based methods offer a feasible option but with limited generality. This study addresses the problem of multi-regime combustion from both perspectives and advances the current state-of-the-art in these methods.Acceleration in the FRC solver is achieved by focusing on the most computationally expensive task: chemical integration. The two fold strategy reduces chemistry and utilises solvers that take advantage of the reduction. After briefly discussing chemistry reduction methods, a novel dynamic adaptive chemistry (TRAC), which is based on the dynamic tabulation of reactions in a low-order manifold space is presented. TRAC is analysed in canonical combustion problems, where a speedup of around 30 % was achieved at a negligible loss in accuracy. Despite the gains in computational performance complete description of turbulent reacting flows in the limit of the current computational resources is unfeasible, this leads naturally to the other facet of the study, which is to include generality in manifold based methods. Regarding manifold based methods, two strategies were analysed, namely, the multi-regime flamelet and the multi-mode combustion model. The models were tested in 1-D and 2-D benchmark problems, where the multi-mode combustion method excels at highly stratified flows. Though, for low and moderately stratified flows both the methods show better prediction than conventional manifold methods. The multi-model combustion model is applied to the multi-regime burner (MRB), where it reproduces global and conditional flame statistics. Overall, the objectives of realising multi-regime combustion at various levels of complexity was achieved using the different strategies studied. Lastly, concluding remarks are given for the usability of the methods in context of current HPC scenario.
  

DOCTORAL DEGREE IN APPLIED MATHEMATICS

• SAMANIEGO VIDAL, DANIEL: On decision functions and dichotomous voting systems
  
  Author: SAMANIEGO VIDAL, DANIEL
  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 APPLIED MATHEMATICS
  Department: Department of Mathematics (MAT)
  Mode: Article-based thesis
  Deposit date: 26/09/2024
  Deposit END date: 10/10/2024
  Thesis director: FREIXAS BOSCH, JOSEP | KURZ, SASCHA
  Committee:
       PRESIDENT: SÁNCHEZ SORIANO, JOAQUÍN
       SECRETARI: MOLINERO ALBAREDA, XAVIER
       VOCAL: ALONSO MEIJIDE, JOSÉ MARÍA
  Thesis abstract: Many real world situations involve a set of players (or agents) negotiating and taking a decision among a set of options an expecting a final result, e.g. a vote to pass a bill or a law, making decisions in committees, resource allocations, rankings of athletes or teams in sports subjected to evaluation by judges, grading aggregations, etc. The rules that define the game are crucial for the strategies that the players will adopt and the final outcome of the game. Cooperative Game Theory studies these rules and the relation among the players. In this Thesis we achieve the following goals: We enumerate several important subclasses of simple games in terms of classes of equivalent players and minimal winning models (contributing to the so-called Dedekind’s problem). This objective is achieved through the parameterization of the game as a matrix and a vector satisfying algebraic properties. We axiomatize subclasses of resolute majority functions and enumerate some of them. We characterize the Felsenthal power index and generalize several properties related to this index previously defined for weighted games, and we show a family of indexes satisfying these compelling properties as well an incompatibility result among some of these coherent properties.
  

DOCTORAL DEGREE IN ARTIFICIAL INTELLIGENCE

• NANDI, ARIJIT: Multimodal data stream classification and prediction of e-learner’s emotional states
  
  Author: NANDI, ARIJIT
  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 ARTIFICIAL INTELLIGENCE
  Department: Department of Computer Science (CS)
  Mode: Normal
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: XHAFA XHAFA, FATOS | SUBIRATS MATÉ, LAIA
  Committee:
       PRESIDENT: CABALLÉ LLOBET, SANTIAGO
       SECRETARI: ESCUDERO BAKX, GERARD
       VOCAL: JUAN PEREZ, ANGEL ALEJANDRO
  Thesis abstract: Emotions and emotional intelligence are crucial for students' success both in traditional learning environments (face-to-face classroom), online education (or E-Learning/distance learning), and in more recently developed technological environments such as augmented workspaces (i.e., adaptive training systems based on augmented or virtual reality). Many researchers have examined the role of emotions in improving and optimizing the outcomes of those learning scenarios. Several approaches (ranging from machine learning/ deep learning models) have also been proposed to use one or more data modalities for emotion classification. However, those ML/DL models so far are suitable for offline mode, where data for emotion classification is stored and can be accessed infinitely. In addition, the recent technical developments and emerging Internet of Things (IoT) technologies have added a new dimension to those learning environments, with numerous feedback instruments (such as webcams, fit-bands, and so on) for engagement with learners. This new layer offers immense quantities of data with volume, diversity, and velocity, referred to as multi-modal data streams, as well as additional complexities in real-time data classification. Thus, the core scientific challenge involves systematically designing, developing, and evaluating a system for real-time emotion classification of learners using multi-modal data streams in those learning scenarios.Initially, this thesis investigates and answers the fundamental research questions by concentrating on the construction of a real- time emotion classification system employing multi-modal data streams, with a major focus on physiological signals (such as Electroencephalogram( EEG ), Electrocardiogram ( ECG), Electrodermal Activity ( EDA) and Respiratory Belt (RB)). Then, to address the fundamental questions raised in this thesis, we have devised a series of distinct methodologies, including Real-time Emotion Classification System (RECS ), Real-time Multi-modal Emotion classification System (ReMECS), and Reward Penalty Based Weighted Ensemble ( RPWE). Furthermore, the thesis extends the ReMECS approach to handle decentralized multi- modal data stream processing for real-time emotion classification with users privacy protection, called Federated Learning based ReMECS ( Fed-ReMECS). In addition, the solution of easy deployment of the federated learning-based approach (Docker- enabled Federated Learning ( DFL)) across distributed devices has also been proposed. All these proposed approaches performance is rigorously evaluated using two benchmark datasets, A Database for Emotion Analysis using Physiological Signals ( DEAP) and A Dataset for Affect, Personality and Mood Research on Individuals and Groups ( AMIGOS), demonstrating the superiority over existing state-of-the-art models. Note that these datasets are accessible after signing the End User License Agreement (EULA).As a result, this thesis contributes fundamentally to the core knowledge base in real-time emotion classification using multi-modal data streaming as a necessary prerequisite to precise and robust emotional interaction in different environments in the context of E-Learning.
  

DOCTORAL DEGREE IN AUTOMATIC CONTROL, ROBOTICS AND VISION

• DUARTE MEJÍA, JOSUÉ NEFTALÍ: Power Control and Voltage Quality Enhancement on Inverter-Based AC Microgrids
  
  Author: DUARTE MEJÍA, JOSUÉ NEFTALÍ
  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 AUTOMATIC CONTROL, ROBOTICS AND VISION
  Department: Department of Automatic Control (ESAII)
  Mode: Article-based thesis
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: VELASCO GARCIA, MANUEL | MARTI COLOM, PAU
  Committee:
       PRESIDENT: REY LÓPEZ, JUAN MANUEL
       SECRETARI: DORIA CEREZO, ARNAU
       VOCAL: ACOSTA RODRÍGUEZ, JOSÉ ÁNGEL
  Thesis abstract: Nowadays, the environmental concerns for conventional fossil fuel-based power generation are transforming the energy landscape into a more sustainable system. To this end, distributed generation (DG) units have gradually become more important in modern energy systems with an increasing integration of renewable energy resources (RES). However, this transformation also implies new challenges for operating and controlling the network safely and efficiently, given the variability and intermittency inherent to these resources.Microgrids (MGs) are small-scale power systems that have emerged as promising solutions for integrating RES such as photovoltaic, wind turbines, fuel cells, biogas digestors, etc. However, given the heterogeneous nature of RES, power electronic devices are required to enable their integration into the AC systems. The incorporation of power converters increases the controllability of these resources but also brings new challenges regarding control and protection. In inverter-based AC MGs, the scope of this thesis, the DG units are interfaced with the MG by inverters, which require to be controlled to ensure the correct operation, stability, and voltage quality of the AC system. To solve these challenges, several inverter control approaches have been proposed in the state-of-the-art. Nevertheless, there remain significant challenges, limitations, and research gaps. In particular, the main shortcomings found in the state-of-the-art can be gathered into two main control areas: a) Power sharing and voltage regulation (Power management), and b) voltage unbalance compensation (Voltage quality).On one hand, power sharing and voltage regulation control approaches aim to ensure the voltage amplitude and frequency stability and its regulation within desired limits in islanded AC MGs. However, existing literature exhibits the following shortcomings: line impedance performance dependency, scalability issues, and control loop coupling. On the other hand, voltage unbalance compensation control approaches aim to increase the voltage quality of the MG. However, a lack of robustness and limitations on the place of compensation were found in the state-of-the-art strategies.This thesis aims to investigate novel control strategies to improve the power control performance and increase the voltage quality on inverter-based AC MGs, focusing on addressing the research gaps in the existing literature. The thesis is presented as a compendium of three peer-reviewed papers that collect the main contributions and results of the thesis.These papers propose three novel control approaches that outperform and overcome most of the identified state-of-the-art shortcomings and limitations. The main contributions of the thesis can be summarized as follows:On one hand, regarding power sharing and voltage regulation, the proposed approach exhibits the following key properties, a) the control performance is independent of the line impedance nature, b) scalability with respect to the number of inverters within the MG, and c) decoupling between the voltage regulation control loop and the power sharing control loop.On the other hand, regarding voltage unbalance compensation, the two proposed approaches exhibit the following outstanding properties, a) fair control effort distribution without control data exchange between inverters, b) robustness to connection and disconnection of inverters and loads, c) reduction of communication burden, and d) flexibility to compensate for multiple local/remote nodes.
  
• MASIP ALVAREZ, ALBERT: Contribució a la identificació de models LTI intervalars en el domini de la freqüència
  
  Author: MASIP ALVAREZ, ALBERT
  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 AUTOMATIC CONTROL, ROBOTICS AND VISION
  Department: Department of Automatic Control (ESAII)
  Mode: Normal
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: PUIG CAYUELA, VICENÇ | QUEVEDO CASIN, JOSEBA-JOKIN
  Committee:
       PRESIDENT: VEHI CASELLAS, JOSEP
       SECRETARI: ESCOBET CANAL, TERESA
       VOCAL: BONDIA COMPANY, JORGE
  Thesis abstract: The main objective of this Thesis is to provide an algorithm for the robust identification of models in the form of a transfer function with interval parameters. The starting uncertain data are in the frequency domain; its representation will consist of bands of uncertainty, polygons or other flat figures in the complex plane.To reach the main objective of the work, firstly an extensive analysis of the mathematical tools and the characteristic measures of the candidate signals to excite the process is made. Different alternatives are studied to conveniently excite a process and it is verified that, whenever possible, it is necessary to apply band-limited harmonic signals to obtain information rich in spectral content. Thus, the model obtained will be able to represent the plant's behavior as faithfully as possible.Before proceeding to the robust identification itself, a historical review of nominal identification techniques is carried out. Emphasis is placed on the approach in the form of regressor of the problem. The approximation of the time delay of the plant and a method to decide the most suitable order for the model to be identified are studied.Given the inadequacy of the nominal model when looking at the data, it is proposed to incorporate uncertainty about the identified model in the form of interval parameters.The entire robustness study of the model pivots around Kharitonov's theorem, which assumes independence between the parameters of the polynomials. A chapter is dedicated to determining the frequency response of a transfer function with interval parameters based on this theorem.Within the algorithms proposed for robust identification, the work begins by extending the linear approach in parameters in the case of intervals. But this way of approaching the problem, despite presenting guarantees of convergence and optimality, shows an important fault when considering the frequency response of the identified model: it turns out to be insufficient to guarantee the inclusion of all observed data, since it omits part of the response when it establishes the restrictions of the problem.For this reason it is necessary to reformulate the problem as a non-linear optimization problem. The approach will have as its objective function to obtain the parameters of the model with the least dilation possible and that the response of the model adjusts in the most adapted way possible to the uncertain source data. The constraints will consider the property of inclusion of the data on the part of the model or vice versa. But these restrictions are given in the form of rules or in the form of a nested optimization problem. It is for this reason that it is necessary to properly condition the problem from the beginning.Since it is a non-convex optimization problem, without guarantee of a solution even though the appropriate order of the model is guessed, a previous study of stability and sensitivity is made to provide a seed and limits of the intervals to be found that ease to get the best possible solution.Throughout the Thesis there are application examples, synthetic and experimental, that show the wide scope of the proposed method and the diversity of plants on which it is applied.The thesis covers only linear, continuous and time-invariant (LTI) models. A future investigation would be to extend the results of this Thesis to the linear case with variable parameters (LPV). This would allow to put the interval coefficients of the polynomials of the identified transfer function as a function of one or several parameters that depend, for example, on the operating point of the plant.To avoid the inconvenience of the jumps caused by the restrictions in the form of rules in the optimization problem raised, it is proposed, as future work, to translate the rules as propositional logic.
  
• OLIVARES ALARCOS, ALBERTO: Foundations of ontology-based explainable robots
  
  Author: OLIVARES ALARCOS, ALBERTO
  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 AUTOMATIC CONTROL, ROBOTICS AND VISION
  Department: Institute of Robotics and Industrial Informatics (IRI)
  Mode: Normal
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: ALENYÀ RIBAS, GUILLEM | FOIX SALMERON, SERGIO
  Committee:
       PRESIDENT: BEETZ, MICHAEL
       SECRETARI: RODRIGUEZ AGUILAR, JUAN ANTONIO
       VOCAL: SRIDHARAN, MOHAN
  Thesis abstract: A critical challenge in the design of robots that operate while interacting with humans is to ensure mutual understanding, which contributes to build reliable human-robot interactions. It is an arduous task since interactive scenarios are often uncertain, exposing robots to exogenous situations that affect their ongoing activities. In those cases, robots shall perceive and recognize unexpected changes in the environment, represent and reason about them, and decide how to adapt to them. This will certainly modify robots' internal knowledge, and it is fair to assume that part of the new robot beliefs might be hidden from other agents such as humans. Hence, robots shall also be capable of communicating or explaining the relevant knowledge about those beliefs updates. In this context, this thesis investigates the use of ontologies as an integrative framework for the construction of robot explanations, particularly within interactive settings involving humans. To this end, the thesis starts formulating the scope of the relevant domain knowledge to conceptualize, and it continues proposing novel ontological models and methods for ontology-based robot explanation generation. The first part of the thesis discusses two main contributions: a systematic review and classification of the state-of-the-art that narrows down the target set of reality phenomena to be conceptualized, and the investigation and development of novel robot perception methods to extract from realistic robot experiences the common patterns of the target conceptualization. The second part discusses the two remaining contributions: ontological analysis and modeling of the target domain knowledge, and the design and development of algorithms to construct ontology-based robot explanations. Note that the different ontological models and algorithms were mainly validated in collaborative and adaptive robotic scenarios. However, they were conceived from a foundational perspective, and we think that their scientific value extrapolates to other application domains (e.g. assistive robotics). Overall, the scientific contributions of this thesis set a solid foundational basis for the ontology-based explainable robots domain, boosting the design of trustworthy interactive robots.
  

DOCTORAL DEGREE IN BIOMEDICAL ENGINEERING

• SHIRZADI, MEHDI: Neuromuscular function assessment through EMG in using hybrid learning in real-time
  
  Author: SHIRZADI, MEHDI
  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 BIOMEDICAL ENGINEERING
  Department: Department of Automatic Control (ESAII)
  Mode: Article-based thesis
  Deposit date: 01/10/2024
  Deposit END date: 14/10/2024
  Thesis director: MAÑANAS VILLANUEVA, MIGUEL ANGEL | MARATEB, HAMIDREZA
  Committee:
       PRESIDENT: ROCÓN DE LIMA, EDUARDO
       SECRETARI: ALONSO LÓPEZ, JOAN FRANCESC
       VOCAL: GAZZONI, MARCO
  Thesis abstract: Understanding and accurately analyzing electromyography (EMG) signals is paramount for a multitude of applications ranging from muscular function assessment to neural decoding and interfacing. The general objective of this thesis is to obtain novel, detailed and precise information from EMG signals and solving the problem in real time for its future usefulness and application in mobility assistive devices or in motor rehabilitation technologies.This comprehensive study delves into the intricate task of resolving superimposed motor unit action potentials (MUAPs) within EMG signals, evaluating existing algorithms and proposing novel methodologies to enhance accuracy and efficiency.The investigation begins with a comparative analysis of various algorithms proposed in the literature for decomposing intra-muscular EMG signals to extract MUAP waveforms and firing times. Peel-Off (PO), branch and bound (BB), genetic algorithm (GA), and particle swarm optimization (PSO) algorithms are scrutinized for their efficacy in handling superimposed MUAPs. Two sets of MUAP templates are utilized, each designed to challenge the algorithms differently in terms of energy range and similarity, thereby providing a comprehensive evaluation framework. Simulations of 1000 superpositions for each template are conducted, with subsequent resolution using the aforementioned algorithms. The comparison employs the generalized estimating equation and overall rank product to discern significant performance differences and establish an overall ranking, revealing BB as the top performer in the entire dataset, albeit with limitations in real-time applications.Building upon this foundation, a novel algorithm is introduced for resolving superimposed action potentials in both intramuscular EMG (iEMG) and intracortical recordings. The proposed algorithm, termed Discrete Brute force Correlation (DBC) coupled with High-Resolution BC (HRBC) and Fusion HRBC (FHRBC), demonstrates promising results in terms of accuracy and efficiency. Performance assessments on extensive simulated datasets and experimental iEMG signals highlight the superiority of the DBC algorithm, paving the way for real-time neural decoding applications crucial in neural and muscular interfacing domains.Expanding the scope further, the study addresses surface electromyography (sEMG) and its application in muscle force estimation. A novel real-time convex model is proposed, offering interpretability and efficiency in estimating force from sEMG signals. Validation on upper and lower limb datasets showcases remarkable performance, with the proposed method outperforming state-of-the-art techniques across various metrics. The model's applicability extends to load sharing, robotics, rehabilitation, and prosthesis control for both upper and lower limbs, underscoring its potential impact in diverse fields.In summation, this study presents a comprehensive exploration of EMG signal analysis, from resolving superimposed MUAPs to real-time force estimation, offering novel methodologies and insights that advance the frontiers of neural and muscular decoding and their practical applications.
  
• TOST ABADÍAS, ANA: Cognitive function evaluation in pediatric patients with neurodevelopmental disorders by means of EEG data
  
  Author: TOST ABADÍAS, ANA
  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 BIOMEDICAL ENGINEERING
  Department: Department of Automatic Control (ESAII)
  Mode: Article-based thesis
  Deposit date: 01/10/2024
  Deposit END date: 14/10/2024
  Thesis director: MAÑANAS VILLANUEVA, MIGUEL ANGEL | BACHILLER MATARRANZ, ALEJANDRO
  Committee:
       PRESIDENT: POZA CRESPO, JESÚS
       SECRETARI: TAUSTE CAMPO, ADRIÁN FRANCISCO
       VOCAL: SOLE CASALS, JORDI
  Thesis abstract: Neurodevelopmental disorders encompass diverse conditions characterized by delays or impairments in motor, social, language, and cognitive skills. These disordersshare clinical features, making biomarker identification and validation crucial for diagnosis, outcome prediction, and treatment monitoring. Brain research seeks tounderstand normal and abnormal functions by analyzing brain activity in spatial and temporal domains, advancing our knowledge.Electroencephalography (EEG) is a key tool for studying neurodevelopmental disorders. This non-invasive technique offers excellent temporal resolution, enablingthe direct measurement of brain activity and evaluation of neurophysiological oscillations on a millisecond scale. EEG’s portability allows recordings in varioussettings, including with infants and young children, aiding in understanding typical and atypical brain development.This study focuses on EEG-based biomarkers for Rett syndrome (RTT), a rare neurodevelopmental disorder involving global psychomotor development degeneration.RTT primarily affects females due to mutations in the MECP2 gene on the X chromosome, with an occurrence rate of 1 in 10,000-15,000 newborns. Symptomsemerge between 6 and 18 months, progressing to cause developmental delays, seizures, coordination and movement difficulties, and social and communicationimpairments.Assessing cognitive and social aspects in RTT patients is challenging due to the absence of speech, declining purposeful hand movements, and emerging autismsymptoms. However, research shows that RTT patients can communicate through pre-intentional methods, with eye gaze being particularly effective when usingeye-tracking technology. This allows for quantifiable assessments of cognitive and social aspects.The study investigated neural responses in RTT patients during cognitive tasks using eye-tracking and wireless EEG to measure brain activity. The goal was toenhance neuropsychological abilities and provide cognitive training to improve communication deficits. However, EEG registration in awake pediatric patients withintellectual and motor disabilities is challenging due to artifacts from uncontrolled movements and muscle activity, necessitating the development of an optimalartifact rejection method for reliable results.The thesis developed an artifact rejection strategy effective across all signal types, exploring energy-based and distribution-based methods. Performance validationinvolved classifying data by variability and using density estimators for visualization and probabilistic categorization.The second objective was to assess brain activation changes from cognitive training over four days using spectral EEG analysis during resting state with eyes open(EO-RS), active training (AT), and passive training (PT). This aimed to understand how cognitive training influences brain activity patterns over time and betweenstates.The third objective was to evaluate connectivity during a single session, comparing AT and PT with EO-RS. Connectivity was assessed using magnitude squaredcoherence (MSC) and cross mutual information function (CMIF) to determine whether cognitive stimulation improves brain connectivity and information flow, aimingto identify the most effective protocol and provide insights into RTT pathophysiology and therapeutic interventions.In conclusion, this thesis advances the understanding of RTT and its therapeutic interventions. The effective artifact rejection strategy addressed challenges in EEGdata analysis for pediatric patients with neurodevelopmental and motor disorders. Findings from spectral and connectivity analyses showed cognitive trainingbenefits, including shifts in power to fast frequency bands, increased connectivity, and reduced brain asymmetry. These insights support developing targetedinterventions and therapies for improved outcomes in RTT.
  

DOCTORAL DEGREE IN BUSINESS ADMINISTRATION AND MANAGEMENT

• RICO FLOR, CRISTINA: Un planteamiento metodológico acerca de la mejora en el sector público del Principado de Andorra. La tramitación administrativa
  
  Author: RICO FLOR, CRISTINA
  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 BUSINESS ADMINISTRATION AND MANAGEMENT
  Department: Department of Management (OE)
  Mode: Normal
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: CAÑABATE CARMONA, ANTONIO
  Committee:
       PRESIDENT: PEÑA LÓPEZ, ISMAEL
       SECRETARI: COLL BERTRAN, JOSEP
       VOCAL: ALET VILAGINES, JOSEP
  Thesis abstract: Administrative procedures are the most common form of interaction between citizens and the Administration, serving as the mechanism through which public services are provided. The aim of this thesis is to demonstrate that administrative procedures can be improved by applying process management and game theory.The research question posed is: Can administrative procedures be improved through the application of process management and the definition of a Nash equilibrium for the strategies that the Administered and the Administration can follow? As we will see, the application of the proposed methodology allows us to identify significant improvement opportunities that will be useful for enhancing administrative procedures. From this experience, fundamental knowledge will be obtained that will serve both for its application in future projects to improve processes in other areas of this Administration, as well as in other public administrations.The research has three objectives: 1) To identify which aspects of administrative procedures could be improved to increase user satisfaction, 2) To define the best strategy for the citizen to follow to successfully complete the procedure, and 3) To define the best strategy for the Administration to follow to increase the satisfaction of users of the service, with the priority of optimizing the management of public resources.The work is structured into two parts, each applying a different methodology. This approach to research is based on current methodological trends used in the evaluation of public policies.In the first part of the research, improvement in the service provider is addressed through the application of Process Management for Public Administration (PMPA). This methodology has been specifically created to design improvement processes in Public Administration.The second part of the thesis focuses on considering administrative procedures as a strategic situation involving two agents: the Administration (A) and the Administered (U). Based on this consideration, the following hypothesis was defined: “Given the strategic situation between the Administration and the Administered, which involves carrying out the administrative procedure, the optimal solution will be reached when neither the Administration nor the Administered have reasons to change their strategy, finding themselves in a state of equilibrium.”The identification of the improvement is resolved through the development of a mathematical model obtained from the application of game theory. This model serves to identify a Nash equilibrium and analyze how this equilibrium point varies depending on the different strategies that the Administration and the Administered can adopt when facing administrative procedures.The results of the first part of the research allow for the identification of specific aspects of the processes that can be improved and how to do so. In the second part, identifying the strategies that lead to a Nash equilibrium allows for specifying what the user should do when facing administrative procedures to achieve a satisfactory result and what is the best strategy for the Administration to provide the best service to citizens, considering the limitations of its resources.The research focuses on improving administrative procedures within the framework of a simplified administration, such as that of Andorra, and in the realm of public policy evaluation, which is increasingly becoming a key aspect for public managers.
  

DOCTORAL DEGREE IN CHEMICAL PROCESS ENGINEERING

• LECHTENBERG, FABIAN: Multi-actor multi-criteria decision-making methods and tools for the implementation of industrial symbiosis and circular economy solutions in the process industry
  
  Author: LECHTENBERG, FABIAN
  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 CHEMICAL PROCESS ENGINEERING
  Department: Department of Chemical Engineering (EQ)
  Mode: Normal
  Deposit date: 01/10/2024
  Deposit END date: 14/10/2024
  Thesis director: GRAELLS SOBRE, MOISES | ESPUÑA CAMARASA, ANTONIO
  Thesis abstract: The quest for sustainable development is both urgent and complex. Paradigms like circular economy (CE) and industrial symbiosis (IS) aim to address this challenge by promoting strategies to achieve a more efficient use of available resources and a reduction of generated waste. However, the implementation of these paradigms faces significant practical challenges that hinder their widespread application. Despite the availability of process integration (PI) methods and tools to identify opportunities for sharing resources and closing material loops in the process industry, and the growing computational power to handle increasingly complex problems, the practical challenge remains to quantitatively, fairly, and transparently demonstrate that the proposed solutions satisfy the objectives of all decision-makers involved.Driven by this challenge, this Thesis aims to bridge the gap by developing frameworks that facilitate multi-actor multi-criteria decision-making. To achieve this, appropriate methods from game theory (GT) are identified to address the multi-actor problem, evaluating the alternatives based on Life Cycle Assessment (LCA) that allows for obtaining quantitative, comparable, and transparent indicators for the multi-criteria problem. Focusing on the process industry, all developed solution methods leverage process systems concepts and mathematical programming. In the first part of this Thesis, GT is utilized as a tool to find solutions that are fair and acceptable for all actors involved. To that end, cooperative profit allocation approaches are applied to PI problems, which have been designed using a proposed framework to reach targeted benefits (economic and environmental) through the introduction of waste-to-resource technologies. Moreover, a Stackelberg competition based framework for the identification of stable outcomes of non-cooperative bargaining between the actors in waste-to-resource pathways, in the absence of a regulatory authority, is proposed and applied a plastic waste recycling case. The second part employs LCA as a tool to quantify the environmental benefits of implementing CE and IS solutions, as a procedure to systematically consider interlinked phenomena such as burden-shifting. Furthermore, this Thesis advances life cycle optimization (LCO) by integrating mathematical programming with LCA to leverage extensive data from commercial Life Cycle Inventory (LCI) databases. Practical contributions include the development of the ``Python-based User-defined Lifecycle Product Optimization'' (PULPO) method, which exploits LCI databases to globally evaluate the individual decisions of the involved processes and their interdependencies. This approach allows the consideration of global supply chain targets in the decision-making of specific links in the chain.The third part synthesizes the insights and approaches developed in the previous two parts and proposes the cooperative PI-MAMCA framework, which includes quantitative procedures for evaluating the stability in the allocation of benefits, based on previously established approaches for multi-actor multi-criteria decision-making. For the first time, simultaneous allocation of various benefits among multiple actors is proposed, demonstrating that, even when considering multiple criteria, fair and acceptable solutions exist.
  

DOCTORAL DEGREE IN CIVIL ENGINEERING

• CORTELLESSA, DAVIDE: A face-centred finite volume solver for viscous laminar incompressible flows using OpenFOAM
  
  Author: CORTELLESSA, DAVIDE
  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: Barcelona School of Civil Engineering (ETSECCPB)
  Mode: Normal
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: HUERTA CEREZUELA, ANTONIO | GIACOMINI, MATTEO
  Thesis abstract: Incompressible flow simulations are crucial for numerous scientific and engineering applications, from automotive aerodynamics to biomedical device design. Traditional finite volume (FV) methods, such as the cell-centered finite volume (CCFV) approach used by OpenFOAM, face significant challenges related to mesh quality, particularly non-orthogonality and skewness. These issues often result in accuracy loss and lead to a complex and time-consuming mesh generation procedure, especially for complex geometries. This thesis addresses these issues by developing and implementing a face-centered finite volume (FCFV) solver for viscous laminar incompressible flows within the OpenFOAM framework.The FCFV method can be seen as a hybridisable discontinuous Galerkin (HDG) method using the lowest order approximation. It achieves first-order convergence for velocity, pressure, and velocity gradient without requiring reconstruction, thus significantly reducing mesh sensitivity. Additionally, the face-centered finite volume method circumvents the Ladyzhenskaya-Babuška-Brezzi (LBB) condition, enabling monolithic solution strategies that solve for velocity and pressure simultaneously or staggered approaches based on algebraic splitting that avoid the introduction of non-physical boundary conditions, unlike standard OpenFOAM solvers.The primary contribution of this thesis is the seamless integration of an efficient FCFV solver into OpenFOAM, offering a robust alternative for cases dealing with complex geometries and/or distorted meshes. This development includes both steady-state and transient formulations and introduces a novel hybrid pressure FCFV formulation to enhance accuracy for higher Reynolds number simulations.Extensive benchmarking and validation against well-known test problems, always compared with standard OpenFOAM solvers, demonstrate the robustness and accuracy of the FCFV solvers, particularly on meshes with high non-orthogonality and skewness. The results indicate that the FCFV method always maintains optimal first-order convergence for all variables and outperforms the standard CCFV solvers currently available within OpenFOAM in cases with distorted meshes. The developed FCFV solvers offer a valuable alternative for OpenFOAM users dealing with complex geometries, enabling the use of unstructured and stretched meshes without sacrificing accuracy or stability.
  
• GARRIDO SALSAS, FRANCISCO JAVIER: THE IMPACTS OF MAIN TRENDS ON THE PORT SECTOR. EVOLUTION TOWARDS A NEW GENERATION OF GREEN AND DIGITAL PORTS
  
  Author: GARRIDO SALSAS, FRANCISCO JAVIER
  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: Barcelona School of Civil Engineering (ETSECCPB)
  Mode: Normal
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: SAURI MARCHAN, SERGI
  Thesis abstract: Trends in logistics and more broadly across technology and energy are resulting in changes on the traditional business models and roles of ports. Since the port ecosystem is going to be considerably different in the following two decades, decision-makers need to be aware about these trends to prioritize investments and build new and dynamic strategic masterplans. This thesis seeks to analyze some current trends impacting on ports and analyze the changes on their roles to define long-term strategy. The results of this thesis will contribute to the state of the art of Ports of the Future by identifying the main trends impacting on ports in the long term (2040). The impacts are identified by means of the Delphi method process within the Port Community of Barcelona. The research allowed to identify which are the key drivers that are going to transform ports: green measures to decarbonize maritime transport and supply chains; circular economy hubs to produce or customize on site and on demand products in port areas; new physical and digital infrastructures for automated and connected vehicles and port terminals; and finally, a fully digitalization to offer new services (track and trace, call optimization, etc.) as well as an optimized supply chain oriented to offer resiliency for the hinterland clients of the ports. These trends will change the long-term port business ecosystem. The research uses Business Canvas Model methodology to identify the future port management dynamics, role and strategy. The results outline conceptual actions to be considered and introduced in port planning to ensure its sustainable growth in harmony with their nearby societies. The conclusions taken based on the case study of the Port of Barcelona are extended to other European ports. The thesis studies the evolution of the ship size, which is a relevant factor in order to plan the investments needed in port infrastructure. The analysis is focused on the container segment which is one of the most relevant in maritime trade. Since the container ship was born, we have seen an impressive increase in order to get advantage of the economies of scale. In the last two decades, the capacity of vessels has been trebled. Despite the exponential growth experienced in this sector, individuals question if it is possible to reach a peak capacity, as has occurred with bulk cargo vessels and, recently, aircraft. This thesis aims to predict the possible size and dimensions of a new generation of mega container ships. Based on economy of scale, port infrastructure, demand and environmental trends and naval design criteria the limit ship size has been estimated. The results suggest that it is still possible additional slight increases of the ship size. This thesis allows Port Authorities to understand the needs of shipping container industry to plan the expansion and investment necessary in their ports.In terms of social sustainability, the research explores how is going to impact the identified trends in the human capital of ports, focusing on the introduction of new technologies. Among others, ICT, cloud technology, 5G, automation, augmented reality, artificial intelligence, block chain and Big Data Analytics are going to conduct several major changes in the port job market. The thesis analyses the impacts of these changes on the capacities and training of port personnel based on questionnaires and interviews to relevant ports of different continents. Finally, in terms of environmental sustainability, the thesis explores measures for decarbonization of ports, due to the fact that it is expected to be a key strategic factor. In this dimension, the thesis focusses on one of the measures with higher impact on reduction of GHG emissions and air pollution, which is the On Shore Power supply. presenting the current state of the art of OPS in ports and the main challenges and barriers in the future. The analysis is linked with the Energy Transition strategy of ports.
  
• LEMARDELE, CLEMENT: Optimizing Two-Echelon City Logistics with Autonomous Vehicles: An Integrated Assessment Framework for Sustainable Last-Mile Deliveries
  
  Author: LEMARDELE, CLEMENT
  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: Barcelona School of Civil Engineering (ETSECCPB)
  Mode: Article-based thesis
  Deposit date: 30/09/2024
  Deposit END date: 11/10/2024
  Thesis director: ESTRADA ROMEU, MIGUEL ANGEL | PAGES GIRALT, LAIA
  Thesis abstract: As the improvement of last-mile logistics operations becomes a more and more pressing challenge to make our cities more sustainable, both from an economic and environmental perspective, a wide sample of new technologies and innovative distribution schemes are currently being piloted by logistics companies and studied within the research community. Beyond the necessary shift in the powertrain technologies, from internal combustion engine vehicles to electric ones, more efficient delivery strategies and fleet typologies are needed. This is especially flagrant in the particular use case of the courier, express, parcel market, which has surged in the last few years and is the source of many inefficiencies in our neighborhoods.In this context, two-echelon networks appear as potential solutions. In these schemes, the journey of freight is divided into two distinct parts, first from the carrier’s distribution center to a network of micro-hubs and then to its final destination. Nevertheless, even if there is a reduction of the total travelled kilometers and greenhouse gas emissions, two-echelon deliveries using e-cargobikes, which is the most common model at the moment, may result in more operation costs than conventional deliveries with vans because of more complex logistics processes and higher infrastructure costs. In addition, e-cargobikes have a lower capacity, which affects their operational efficiency since more delivery routes are needed, leading to an increase of the vehicle fleet.To make two-echelon delivery schemes economically sustainable, which will eventually lead to large-scale deployments, autonomous vehicles (AVs), both ground ones and air delivery drones, seem to be promising solutions with the potential to reduce the delivery operation costs and, at the same time, the emissions of greenhouse gases. Nevertheless, the exact benefits of AVs, jointly with other technologies, such as intelligent parcel lockers, still need to be assessed at a large scale and from a holistic point of view, beyond purely operational considerations.As a consequence, in this doctoral thesis, we build a complete assessment framework for AV technologies in the context of city logistics, from planning to operations, which combines the continuous approximation methodology and a discrete optimization procedure to efficiently tackle the capacitated multi-trip vehicle routing problem with time windows and battery capacity constraints.More specifically, distinct parsimonious logistics models including the usage of air drones, ground robots and parcel lockers are built considering the characteristics of these different fleets. Moreover, a thorough life-cycle analysis is performed to quantify the environmental impact of these technologies. These different logistics models are then assessed at a large European scale and integrated with discrete optimization methods to give a holistic vision of AV operations for last-mile logistics.This doctoral thesis will help practitioners, researchers and city representatives understand the main challenges at stake with autonomous technologies from a logistics perspective, apart from the social and regulatory aspects, which are not considered. The obtained results are encouraging since the combination of a two-echelon network of delivery micro-hubs with ground autonomous delivery robots has the potential to reduce city logistics costs by around 20% in adequate conditions. Finally, externalities could also be reduced but a very particular focus should be set on the reduction of the greenhouse gas emissions from the autonomous vehicle production, to avoid observing an increase of the global warming potential on a life-cycle basis.
  
• MALIKOSKI VIEIRA, LUAN: Low-order face-based approaches for incompressible computational fluid dynamics
  
  Author: MALIKOSKI VIEIRA, LUAN
  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: Barcelona School of Civil Engineering (ETSECCPB)
  Mode: Change of supervisor
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: HUERTA CEREZUELA, ANTONIO | GIACOMINI, MATTEO | SEVILLA CÁRDENAS, RUBÉN
  Thesis abstract: The fast and accurate simulation of laminar and turbulent incompressible flows is crucial in science and engineering. Low-order numerical strategies, particularly finite-volume (FV) methods based on cell-centred and vertex-centred approaches, remain essential in CFD, especially in industrial settings, due to their favourable trade-off between computational cost and accuracy. However, these methods face challenges such as stabilising convective-dominated flows, handling velocity-pressure coupling, and managing numerical flux reconstruction on distorted and stretched grids. The face-centred finite volume (FCFV) method emerges as an alternative to standard FV methods. Derived from a mixed formulation of the discontinuous Galerkin method, FCFV avoids flux reconstruction at cell faces, making its accuracy and convergence nearly insensitive to grid quality. It also satisfies the Ladyzhenskaya-Babuška-Brezzi (LBB) condition without special treatment for velocity-pressure coupling. This work showcases the FCFV method for simulating laminar and turbulent incompressible flows for the first time. The formulation is based on the Reynolds-averaged Navier-Stokes (RANS) equations coupled with the negative Spalart-Allmaras (SA) model. Three new convective stabilisations inspired by Riemann solvers are proposed, along with monolithic and staggered solution strategies for the RANS-SA system and two relaxation strategies for pseudo-time marching. A new hybrid pressure FCFV formulation is also introduced to improve the FCFV accuracy in laminar flow simulations by enriching the pressure space through relaxed compressibility conditions. Both FCFV and hybrid pressure FCFV achieve first-order convergence of velocity, velocity gradient tensor, and pressure, accurately predicting engineering quantities such as drag and lift on structured and unstructured meshes. By avoiding gradient reconstruction, these methods are less sensitive to mesh quality, even on highly distorted grids. Numerical benchmarks for laminar and turbulent, steady and transient cases assess the performance, accuracy, and robustness of the proposed methodologies. Implemented in Fortran 90, these methods lay the foundation for the integration of FCFV techniques within the CFD community. The work concludes with a detailed discussion of the Fortran 90 FCFV code implementation.
  
• NAZARETH LOPEZ, RAFAEL: Continuous-discrete numerical modeling of the thermomechanical behavior of granular media supported by experimental campaign
  
  Author: NAZARETH LOPEZ, RAFAEL
  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: Barcelona School of Civil Engineering (ETSECCPB)
  Mode: Normal
  Deposit date: 01/10/2024
  Deposit END date: 14/10/2024
  Thesis director: FRANCI, ALESSANDRO | OÑATE IBAÑEZ DE NAVARRA, EUGENIO
  Thesis abstract: Granular materials, ranging from soils and food grains to construction aggregates and pharmaceutical powders, are prevalent in both natural and industrial contexts. Their complex physical behavior, which can exhibit both solid- and fluid-like properties depending on several external and internal factors, arises from their discrete composition, characterized by intricate particle interactions. This complexity is further amplified by thermal effects, which explains the current gaps in achieving a comprehensive understanding of the thermomechanics of granular matter. This thesis explores the thermomechanical behavior of granular media from different perspectives, including numerical and experimental analyses. In particular, two key thermal effects are addressed throughout the research, namely, heat generation from mechanical energy dissipation and thermal expansion in confined systems. In the physical experiments, the heat generation phenomenon is studied for granular mixing operations using two widely-used industrial devices: a rotating drum and a bladed mixer. In both setups, the temperature rise of granular flows is measured under varying operational conditions. Regarding numerical investigations, two approaches are developed. An efficient Discrete Element Method (DEM) framework is used to investigate heat generation mechanisms and provide insights into the thermomechanical behavior of granular flows. Additionally, a novel multiscale numerical framework is developed, coupling continuous and discrete methods through a machine-learning-based surrogate model, to efficiently simulate thermal expansion in confined granular media. In both strategies, the underlying objective is to reduce the high computational cost of simulating granular media, allowing for large-scale analyses in terms of both time and space.
  
• SANZ RAMOS, MARCOS: Numerical modelling of non-Newtonian shallow flows
  
  Author: SANZ RAMOS, MARCOS
  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: Barcelona School of Civil Engineering (ETSECCPB)
  Mode: Article-based thesis
  Deposit date: 30/09/2024
  Deposit END date: 11/10/2024
  Thesis director: BLADE CASTELLET, ERNEST
  Thesis abstract: Numerical modelling of natural phenomena, particularly weather-related which are the 90 % of global disasters, is essential to analyse and predict hazardous situations for the people, the economy and the environment. The evolution of these numerical tool, from simple one-dimensional to complex three-dimensional models, to simulate hydrological hazards like floods, mass movements, and avalanches is challenging, especially those in which the fluid can be characterized as non–Newtonian flows.This PhD thesis focusses on the extension of Iber, a depth-averaged two-dimensional hydrodynamic numerical tool, to simulate non–Newtonian shallow flows. To that end, a particular numerical scheme based on an upwind discretisation to ensure for the non–velocity-dependent terms of the shear stresses has been developed to counterbalance the pressure forces. This ensures the stop of the fluid according to the rheological properties of the fluid, even in steep slopes and complex geometries. The code besides being validated and applied in theoretical, analytical, and in common and non–common non–Newtonian shallow flows in real situations, it has been fully integrated in the graphical user interface of Iber. This facilitates the model build-up, setup and results visualization converting the new code in a software suite fully operational for all practitioners.
  
• SARWAR, SAMRA: Transport Planning Strategies in the Context of Autonomous Vehicles
  
  Author: SARWAR, SAMRA
  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: Department of Civil and Environmental Engineering (DECA)
  Mode: Normal
  Deposit date: 01/10/2024
  Deposit END date: 14/10/2024
  Thesis director: SAURI MARCHAN, SERGI
  Committee:
       PRESIDENT: VASALLO MAGRO, JOSÉ MANUEL
       SECRETARI: ESTRADA ROMEU, MIGUEL ANGEL
       VOCAL: MASEGOSA ARREDONDO, ANTONIO DAVID
  Thesis abstract: With the constant advancements in autonomous drive technologies and the growing popularity of tactical urbanism in street reorganization, it is essential to conduct research to evaluate the effects of these new forms of mobility on transportation networks. This research thesis explores their effects on different variables of transportation systems, such as congestion pricing and parking pricing during peak commute times. It also investigates how superblocks and autonomous vehicles impact traffic flow on a larger scale. Furthermore, it evaluates the effectiveness of public transportation by integrating shared autonomous vehicles to reduce congestion at critical locations.This thesis uses Vickery's bottleneck model to calculate the total travel cost for dynamic traffic patterns during morning and evening commutes in the presence of automated vehicles. To achieve the system's optimum, this research employs a time-dependent congestion toll and social parking pricing strategy. This thesis applies the formulated model to a numerical study with an assumed network link. The numerical case study's conclusions clarified the importance of AVs in the network to reduce congestion toll and parking pricing.This thesis proposes the superblock model as a way to make the streets liveable in the presence of AVs. The research employs a genetic algorithm to implement the superblock model in a network with a grid structure. It addresses the dynamic user equilibrium assignment for demand and topology segmentation. In this context, the thesis analyzes the performance of a network with superblocks and AVs through a macroscopic fundamental diagram.Furthermore, in terms of sustainable public transport planning, AVs also play an important role in increasing the system's performance. Therefore, this thesis formulated a methodology for multimodal transport that combines public transport and shared AVs to improve network efficiency. In this context, the research measures public transport performance metrics, such as passengers' total travel time (which includes walking, waiting, and vehicle time), after implementing the optimal multimodal transport strategy. The results suggest that integrating shared AVs at critical locations of public transport improves the overall efficiency and connectivity of the network.Finally, the numerical studies presented in this thesis add value to the current state of the art in terms of optimal toll pricing, parking pricing, superblock model, shared AVs, and public transport performance in the presence of emerging technologies such as "Autonomous Vehicles." The methodologies designed in this thesis can be used by other researchers, mobility planners, and policymakers to achieve the optimal congestion tolls, to optimize the network having superblocks, and to improve the public transport network performance.
  

DOCTORAL DEGREE IN COMPUTATIONAL AND APPLIED PHYSICS

• DUQUE GIJON, MARIA: Experimental study of the coherence of the light emitted by a semiconductor laser with optical feedback
  
  Author: DUQUE GIJON, MARIA
  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 COMPUTATIONAL AND APPLIED PHYSICS
  Department: Department of Physics (FIS)
  Mode: Normal
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: MASOLLER, CRISTINA | TIANA ALSINA, JORDI
  Committee:
       PRESIDENT: CORNELLES SORIANO, MIGUEL
       SECRETARI: VILASECA RICART, MERITXELL
       VOCAL: HONG, YANHUA
  Thesis abstract: Semiconductor lasers are part of our daily lives, finding applications in telecommunications, sensing, metrology, and biomedicine due to their compact size, efficiency, and versatility. This thesis explores how optical feedback influences the temporal and spatial coherence of semiconductor lasers through a technique based on random intensity patterns, i.e., speckle. Optical feedback involves reinjecting part of the emitted laser light through an external reflector, inducing various nonlinear dynamics operating regimes. While much research has focused on optical feedback's effects on temporal coherence, its impact on spatial coherence is less studied. This thesis proposes the speckle contrast analysis to study the coherence of semiconductor laser light under optical feedback. Speckle patterns arise from the interference of coherent light when it propagates through a diffusive medium. This technique enables the quantification of the coherence of the light providing, valuable insights into the spatial coherence of laser light. High speckle contrast patterns reveal valuable information about both the laser light and the diffusive medium. However, speckle can degrade image quality in imaging applications, requiring speckle mitigation. The thesis aims to study how optical feedback affects the coherence of the light emitted by a semiconductor laser, with the particular goal of identifying conditions where feedback reduces the light coherence and, consequently, the speckle contrast.The first part of this thesis investigates the emergence and evolution of coherence during the laser turn-on transition under different optical feedback scenarios with respect to the non feedback scenario, using a mirror and a diffractive grating as reflectors, and using a multimode fiber as a diffusive medium.The second part proposes a procedure to differentiate between temporal and spatial coherence using speckle pattern analysis with three different diffusive mediums: multimode fiber, multimode fiber and a diffuser, and single-mode fiber and a diffuser. By analyzing speckle contrast and relating it with optical spectrum measurements, we reveal the evolution of the coherence in a solitary and optically fed back semiconductor laser across a huge range of pump currents, highlighting the difference between temporal and spatial coherence. Complementary to speckle contrast technique we have made use of the spatial entropy measure to unveil nonlinear spatial correlations between pixel values of speckle images.This thesis also investigates the impact of sinusoidal modulation in the pump current on the coherence of semiconductor lasers with optical feedback. The modulation amplitude and frequency play a crucial role in influencing coherence. The goal is to identify the optimal modulation conditions under which a fed back semiconductor laser emits light with lower spatial and temporal coherence compared to scenarios without modulation.Finally, this thesis includes a chapter on the impact of optical injection on the timing jitter of a semiconductor laser. Timing jitter refers to the variability in the timing of emitted light pulses from the semiconductor laser, which can significantly impact the precision of optical systems, as the optical analog-to-digital converters.This study was carried out at the Photonics Laboratory at IFCA under the supervision of Dr. Ana Quirce, as a secondment.This thesis is devoted to an experimental study of the effects of Optical feedback or optical injection on the temporal and spatial characteristics of the output emission of semiconductor lasers.
  
• VURGUN, EDA: Compact Binary Millisecond Pulsars: X-ray Observations and Numerical Simulations
  
  Author: VURGUN, EDA
  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 COMPUTATIONAL AND APPLIED PHYSICS
  Department: Department of Physics (FIS)
  Mode: Normal
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: GARCÍA SENZ, DOMINGO | LINARES ALEGRET, MANUEL
  Committee:
       PRESIDENT: CASARES VELÁZQUEZ, JORGE
       SECRETARI: JOSE PONT, JORDI
       VOCAL NO PRESENCIAL: YAVUZ EKSI, KAZIM
  Thesis abstract: The thesis deals with millisecond pulsars (MSPs), a fascinating group of neutron stars distinguished by their exceptionally fast rotation periods (Ps < 30 milliseconds) and their strong magnetic fields (of the order of 10^8 to 10^9 Gauss). These cosmic objects are thought to form through a process in which mass transfer from a companion star in a binary system accelerates or "recycles" the neutron star to these rapidly rotating periods. This recycling process not only rejuvenates the pulsar, but also provides insights into the complex mechanisms of stellar evolution. The thesis is divided into two parts, both focused on the phenomena associated with MSPs. The first part explores a population of neutron stars using X-ray observational data. Globular clusters (GCs) are known to be particularly efficient at forming MSPs and low-mass X-ray binaries (LMXBs). due to their high stellar densities. The study presents a detailed investigation of the globular cluster M28 (NGC 6626) using the complete Chandra ACIS ensemble data (2002-2015). The X-ray (LX) luminosity, spectrum and orbital modulation of 7 compact MSP binaries in the cluster were examined. Among the outstanding results, an orbital flux modulation was discovered in the X-rays of M28I (IGR J18245–2452), centered around the lower conjunction of the pulsar. In addition, analysis of the spectrum of the neutron star in the inactive LMXB allowed us to constrain its mass and radius, finding radii between 9.2 and 11.5 km for atmospheric models of 'hydrogen and 13.0 to 17.5 km for helium models, with a mass of 1.4M⊙ (68% confidence interval). The long-term variability of the 46 brightest X-ray sources was also investigated, discovering six new low-luminosity variable X-ray sources in M28. The second part of the thesis studies the interaction of the magnetic field of the neutron star with the nearby accretion disk, performing detailed magnetohydrodynamic (MHD) simulations that incorporate realistic disk structures into the numerical simulations. The aim is to elucidate the mechanism that drives state transitions in transition MSPs, whose physical origin is still poorly understood. The simulations use a newly developed MHD axisymmetric smoothed particle dynamics (SPH) code, exploring four interaction scenarios based on the distance between the neutron star and the inner disc radius. Surface magnetic fields typical of MSPs (B0 = 9.6 × 10^7 G), similar to the known value for the MSP PSR J1023 + 0038, were used and the field-disc interaction was investigated as a function of angle of tilt between the axis of rotation and the magnetic axis of the neutron star. The thesis focuses on numerical simulations of disk structures, with and without magnetic fields. Initial simulations without magnetic fields established a stable disk configuration, which served as a basis for further studies. Simulations that introduced a magnetic field with varying tilt angles revealed that the aligned rotators maintained stability over several orbits, while higher tilt angles led to disk instability. Altogether, this thesis contributes significantly to the understanding of stellar life cycles, binary interactions and extreme physical conditions in these extraordinary celestial objects, the MSPs.
  

DOCTORAL DEGREE IN COMPUTER ARCHITECTURE

• DEVIGILI, MARIANO: Applications of the OCATA optical layer digital twin
  
  Author: DEVIGILI, MARIANO
  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: Department of Computer Architecture (DAC)
  Mode: Normal
  Deposit date: 01/10/2024
  Deposit END date: 14/10/2024
  Thesis director: VELASCO ESTEBAN, LUIS DOMINGO | NAPOLI, ANTONIO
  Committee:
       PRESIDENT: CASELLAS REGI, RAMON
       SECRETARI: COMELLAS COLOME, JAUME
       VOCAL: SAMBO, NICOLA
  Thesis abstract: Optical transport networks (OTNs) are a core infrastructure and key-enabler of today’s hyper-connected society as most of the Internet data traffic is transferred over optical fibers. Traffic demand is experiencing rest-less growth as Internet-services are reaching increasing audience and capacity-hungry applications are arising (e.g., industry 4.0). In view of this, constant innovation is required in OTNs to accommodate the requested capacity while minimizing the cost. In this scenario, digital twins (DTs) – intended as a combination of models self-adjusting with their physical counterpart and of algorithms acting on the network for specific applications – are being proposed as a solution for: 1) maximizing the transport capacity by reducing the network margins; 2) pave the way towards optical network automation. The main objective of this PhD Thesis is to improve network operation based on the use of DTs algorithms and models for failure management, lightpath provisioning and optical amplifier control. To achieve this goal, different machine learning (ML) algorithms were investigated and the capabilities of the OCATA DT were extended. This main goal is achieved by the following three specific goals:1. Applications of Optical Layer DT During Network Operation. The OCATA capabilities are extended for quality of transmission (QoT) estimation and failure management. Tailor-made features are extracted from IQ constellation samples, which show correlations with QoT metrics and with failures-induced signal degradations. Next, specific ML-based models and algorithms for QoT estimation, soft-failure detection, identification and severity estimation are proposed. Results from both simulation and experiments show noticeable accuracy on the estimation of QoT and on the prediction of failures affecting the transmitter, optical filters and amplifiers. Furthermore, this approach was confirmed also for detecting and identifying spectrum anomalies. 2. Applications of Optical Layer DT for Lightpath Provisioning. OCATA capabilities are extended for modulation formats besides 16-quadrature amplitude modulation (QAM) and for digital subcarrier multiplexing signals (DSCM). Firstly, an algorithm for lightpath provisioning is proposed and evaluated based on simulations. Secondly, I experimentally evaluate its accuracy to predict the impact of optical filtering penalties. The simulations show an overall high accuracy for different signal formats and demonstrate their viability for lightpath provisioning. Moreover, the models showed the most advantageous trade-off between accuracy and execution time when compared with other existing methods. Finally, the experimental results demonstrate the feasibility of implementing such models to perform quality of transmission estimation for DSCM signals.3. Application of Optical Layer DT for Amplifier Control. DT models were designed to assist a network controller in performing informed decisions when re-configuring dynamically optical amplifiers under varying channel loadings. Experimental characterization processes were performed on pluggable EDFAs. Then, ML models based on deep learning (DL) and ensemble methods were compared in terms of accuracy and computation speed. After time-consuming hyper parameter optimization (HPO) procedures, DL models showed to achieve both the best performance on the training data set and the best generalizability on unknown dataset. Furthermore, it was shown that substantial generalization error reduction can be achieved employing transfer learning (TL) techniques.
  
• YU, CHENLE: Leveraging the potential of task-based programming with OpenMP task graphs
  
  Author: YU, CHENLE
  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: Department of Computer Architecture (DAC)
  Mode: Normal
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: QUIÑONES MORENO, EDUARDO | ROYUELA ALCÁZAR, SARA
  Committee:
       PRESIDENT: TERBOVEN, CHRISTIAN
       SECRETARI: LABARTA MANCHO, JESUS JOSE
       VOCAL: MARONGIU, ANDREA
  Thesis abstract: The task execution model is widely used in computer engineering, it helps developers to design, develop and understand software systems. OpenMP is the de-facto programming model to parallelize sequential algorithms on shared-memory machines. Coupled with the task parallelization, OpenMP is able to conveniently parallelize structured and non-structured applications, it also allows users to offload work onto accelerators as target tasks. However, the runtime overhead incurred by the OpenMP tasking model is an important concern for users to develop OpenMP task programs. This work focuses on improving OpenMP tasking model.Firstly, we carried out an analysis of the performance overhead and bottleneck of mainstream task implementations and proposed a solution in the OpenMP specification to tackle it. To elaborate, we observe that a significant portion of the overhead in the tasking model stems from thread contention, where multiple threads compete to access shared resources simultaneously, such as task queues, causing these threads to stall. As the number of cores in modern architectures increases, this further hampers the scalability of OpenMP tasking. We propose a mechanism that creates graphs representing sets of OpenMP tasks. Once built, executing such graphs incurs less runtime overhead by drastically reducing the access to shared resources. This mechanism is exposed to the users as a new OpenMP directive, namely Taskgraph.Secondly, we implemented the proposed solution, the taskgraph directive, in both GCC (prototype implementation) and LLVM compilers (complete implementation). Initially, our focus was on the GCC compiler, particularly its runtime system: libgomp. Our prototype implementation in this compiler demonstrated promising performance improvement using taskgraph. However, it also revealed a performance bottleneck in libgomp: all tasks are scheduled into a common queue, leading to significant contention and resulting in poor performance and scalability compared to LLVM.The complete implementation of the taskgraph framework is in the LLVM compiler. Our modifications in the compiler range from the front-end to the middle-end of the compiler, in addition to its runtime library: libomp. This framework allows users to declare taskgraph directives in OpenMP C/C++ code to create graphs conveniently, at either compile time or run-time. The experiments show that the taskgraph framework outperforms the original task implementations from GCC and LLVM. We carried out the experiments on nodes of the Marenostrum4 supercomputer.Finally, we enhance the OpenMP offloading mechanism by leveraging taskgraph. Particularly, we implemented the transformation of taskgraph to CUDA graphs. Consequently, our framework enhances the interoperability of OpenMP with other programming models (in this case, CUDA) and improves the performance of OpenMP accelerator model by alleviating the synchronization overhead.With these contributions, this thesis ameliorates both the OpenMP tasking and accelerator models. The framework has been used by other Ph.D. students to develop their research, for example, Cyril Cetre from Thales Research and Technology successfully improved the performance of a cyber-physical application by utilizing static generation of CUDA graphs, as presented in this manuscript. Furthermore, the OpenMP Language Committee accepted our proposition to include the taskgraph directive into the OpenMP Specification v6.0. This thesis also contributed to the upstream LLVM repository. These commits are mainly focused on the record-and-replay mechanism of taskgraph, serving also as a basis for the official taskgraph implementation in the LLVM. We hope with these endeavors, this work will promote the use of OpenMP task in general.
  

DOCTORAL DEGREE IN COMPUTING

• MOTGER DE LA ENCARNACION, JOAQUIM: Natural Language Processing Methods for Document-based Requirements Specification and Validation Tasks
  
  Author: MOTGER DE LA ENCARNACION, JOAQUIM
  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 COMPUTING
  Department: Department of Computer Science (CS)
  Mode: Article-based thesis
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: FRANCH GUTIÉRREZ, JAVIER | MARCO GOMEZ, JORDI
  Thesis abstract: Requirements engineering (RE) is fundamental to successful software development, especially in modern, large-scale projects. Efficient management of text-based artefacts is key to accurate elicitation, refinement, and validation of requirements. Despite the industrial trend towards adopting natural language processing (NLP) methods, challenges in their pervasiveness, reliability, scalability, and reusability persist. Moreover, the advent of large language models (LLMs) has set the groundwork for further research in automated document analysis in the field of RE.This thesis explores the integration of NLP methods and tools to automate and enhance RE tasks (NLP4RE) in three document-oriented areas: requirements traceability, requirements analysis for information retrieval, and requirements feedback gathering. For requirements traceability, methods for dependency and duplicate detection in text-based requirements documents are proposed and evaluated. In requirements analysis, a knowledge graph-based approach is developed to create adaptive, crowdsourced repositories of RE-related documents. For requirements feedback gathering, techniques for extracting features from user reviews and analyzing feedback are presented and evaluated.This research is shaped in the context of multiple case and sample studies validated empirically, demonstrating their effectiveness in real-world scenarios. The contributions presented in this thesis entail advancements in streamlining RE tasks and improving the accuracy, efficiency and adoption of NLP4RE tools and methods. Ultimately, this thesis aims to provide novel insights, methodologies and technical contributions to the NLP4RE field.
  

DOCTORAL DEGREE IN EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS

• SEGUÉS AGUASCA, EDGAR: New Timber - Steel Construction System for Improved Lateral Resistance Buildings
  
  Author: SEGUÉS AGUASCA, EDGAR
  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 EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS
  Department: Department of Civil and Environmental Engineering (DECA)
  Mode: Normal
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: LOPEZ ALMANSA, FRANCISCO | RODRIGUEZ CANTALAPIEDRA, INMACULADA
  Committee:
       PRESIDENT: ARRIAGA MARTITEGUI, FRANCISCO
       SECRETARI: GIRALDO FORERO, MARIA DEL PILAR
       VOCAL NO PRESENCIAL: BENAVENT CLIMENT, AMADEO
  Thesis abstract: In the proposed technology, the timber elements are set in any traditional or innovative way (e.g., light or heavy frame, CLT) and the steel elements are installed as an exostructure. Both parts shall be installed in such a way that the timber members are rather unaffected by the lateral effects (wind and seismic) and the steel ones are pretty untouched by the major gravity loads. In other words, the timber structure withstands the vast majority of vertical forces and the steel exoskeleton supports the lateral forces. If these conditions are fulfiled, the proper design of the steel members can provide an improved lateral resistance. To develop the proposed new hybrid system, once it was conceived, it began to be theoretical calculate with the aim to size the different parts and analyse the feasibility of the system. To carry out this approximation several full-scale buildings (lab models) tested on a shaking table (Fisher et al., 2001; Christovasilis et al., 2009 and Pei et al., 2010) and a real building designed and built in New Zeeland (Milburn, Banks., 2004) were chosen. The obtained outcomes kept pushing us to develop the design of the new system and to analyse and calculate the belts, corners and energy dissipators. As the results were still positive, the process was extended to CLT buildings. Moreover, to ensure sufficient ductility and easy repairability, failure (under extreme seismic events) should arise either in ductile steel members or in straightforwardly replaceable timber parts. Yet more, sacrifice elements (energy dissipators) might be disposed to absorb most of the input energy. In addition, an economical energy dissipator have been designed and analysed during this research such could be installed between the steel exoskeleton and the timber structure. Its application on a building built in New Zealand (Milburn, Banks., 2004) was theoretically analysed with a positive outcome paper published by the authors in (López-Almansa et al., 2015). We applied without success to a European grant to build and test a real scale model. Despite we did not obtained, we decided to carry out the experimental part of this research with available resources and finally, we built and tested 2 scaled models in the shaking table of the “Laboratori d’Enginyeria Sismica i Geofísica” of “Escola Tècnica Superior d’Enginyeria de Camins, Canals i Ports de Barcelona”. Although scale factors do not allow us to extrapolate the numerical results of these tests, the making process of the models and the test themselves, suppose a learning base and give us a deepest knowledge of the hybrid proposed system. We check its feasibility as well as detected the key points to be considered in order to guarantee its correct performance. In addition, new methodologies and design criteria to improve the behaviour and shape of the parts, had been obtained. All this knowledge, encouraged us to promote the invented system and will allow us to reduce costs and get closer targets in our future research. In the next pages you will find all the details of the research summarized above.
  

DOCTORAL DEGREE IN ELECTRICAL ENGINEERING

• RONCANCIO GUZMAN, JOSE ANDRES: Aportaciones a la Caracterización de las Emisiones Ópticas Producidas por Rayos y su Detección Desde el Espacio
  
  Author: RONCANCIO GUZMAN, JOSE ANDRES
  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 ELECTRICAL ENGINEERING
  Department: Department of Electrical Engineering (DEE)
  Mode: Normal
  Deposit date: 01/10/2024
  Deposit END date: 14/10/2024
  Thesis director: MONTAÑA PUIG, JUAN | LÓPEZ TRUJILLO, JESÚS ALBERTO
  Committee:
       PRESIDENT: ARANGUREN FINO, DANIEL
       SECRETARI: RIBA RUIZ, JORDI ROGER
       VOCAL: FABRÓ TAPIA, FERRAN
  Thesis abstract: This research focuses on the characterization of optical emissions generated by various lightning processes, with the aim of improving the interpretation of optical detections made from space. Observations were conducted at the natural lightning laboratory in Barrancabermeja, Colombia, where a set of instruments has been deployed to complement space-based measurements. During the characterization, specific patterns in the optical emissions associated with different lightning processes were identified. For instance, some discharges exhibit oscillations in their optical emissions, possibly related to the initial vertical propagation of the leader within the storm cloud and its subsequent transition to horizontal propagation, a phenomenon observed in both intracloud and cloud-to-ground lightning. Additionally, fast-propagating lightning (less than 6 ms) was detected, generating a characteristic waveform in the optical emission, accompanied by VHF emissions that are captured by localization networks, showing a high correlation with the optical waveform. In the case of leaders propagating downward in cloud-to-ground lightning, their optical emissions overlap with the light detected along the channel, making it difficult to observe optical variations that directly correlate with their propagation.Furthermore, a detailed analysis of the waveforms of optical emissions of lightning with negative continuous current observed from ground was conducted to evaluate the detection capability of these currents by the Geostationary Lightning Mapper (GLM). The comparison of ground-based signals with those obtained from space provided a better understanding of the differences in lightning detections from space, particularly regarding the reduced duration of the reported continuous currents.Additionally, ground support was provided for the ALOFT project, a suborbital measurement campaign focused on investigating high-energy emissions from storm clouds. The ER-2 aircraft, flying at an altitude of 60,000 feet, was equipped with eight instruments, including an array of 25 photometers and two high-energy detectors. As part of the support for ALOFT measurements, an LMA station, a high-energy sensor triggered by VHF signals, a magnetic field LF antenna, and an interferometer were installed on the island of San Andrés, Colombia
  

DOCTORAL DEGREE IN ELECTRONIC ENGINEERING

• BANDAHALLI MALLAPPA, PRASAD KUMAR: Design and Implementation of High-Level Multilevel Inverters: Focusing on 15-level, 25-level, and 33-level Topologies with Asymmetrical Configuration and Optimal Component Choices
  
  Author: BANDAHALLI MALLAPPA, PRASAD KUMAR
  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: Normal
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: MARTINEZ GARCIA, HERMINIO | VELASCO QUESADA, GUILLERMO
  Committee:
       PRESIDENT: BARGALLO PERPIÑA, RAMON
       SECRETARI: VIDAL IDIARTE, ENRIQUE
       VOCAL: FERNÁNDEZ HERRERO, CRISTINA
  Thesis abstract: The primary goal of this thesis is to establish multilevel inverter (MLI) topologies for industrial settings. Because of its numerous benefits, including low power dissipation on powersupplies and low harmonic contents, MLI topologies are utilized in medium- and high-power applications, such as active power filters, FACTS devices, and machine currents. The chosenswitching strategies are crucial in removing harmonic distortion from the output voltage provided by the MLI. Depending on the inverter's power requirements, different topologies and controlstrategies may be selected. However, they have several drawbacks over MLI, such as the need for separate power sources for each stage. Consequently, MATLAB/SIMULINK is used to simulateMLI.This work aims to offer a unique topology for a single-phase 15-level asymmetric MLI to minimize component requirements. The suggested design uses asymmetric DC sources to reach amaximum 15-level output voltage through an H-bridge topology. To enable a 25-level version appropriate for renewable energy applications, the original 15-level MLI structure is furtherimproved, lowering system costs and dimensions. However, the higher component count in MLI presents reliability issues, particularly about the decrease of total harmonic distortion, whichcontinues to be a research focus. Several factors are examined for the proposed 15-level- and the extended 25-level MLI, including total standing voltage, multilayer inverter cost function, andpower loss. Next, it facilitates the integration of renewable energy sources and streamlines the use of components by contributing to a novel topology for 15-level asymmetric MLI. Even thoughmultilevel inverters have many benefits, future developments in this field must address reliability issues related to overall harmonic distortion reduction. Then, a unique 33-level asymmetricalsingle-phase MLI is built, utilizing fewer components and a lower Total Standing Voltage (TSV) at the switches. Variable-rated switches are employed to lower the overall cost of the inverter, andthe distribution of stress among the switches is carefully examined. The suggested design combines four asymmetrical DC sources with twelve switches to generate 33 voltage output levels.The inverter's performance is determined by many crucial factors, including TSV, efficiency, power loss, and cost function (CF). Using a range of combinational loads, the MLI was evaluatedin dynamic load conditions with unforeseen load disturbances, and it was discovered to be stable throughout the operation. A thorough comparison uses graphical representations based on stressvi across switches, stress distribution, switch count, DC source count, gate driver circuits, component count factor, TSV, CF, and other existing topologies. It is demonstrated to be more efficient andbetter in every way. According to simulation and experiments, the Total Harmonic Distortion (THD) is within IEEE guidelines. The suggested framework was created in MATLAB/Simulinkand tested using hardware in a lab environment.
  
• VALLEJO MANCERO, BERNARDO JAVIER: Highly scalable hardware architecture for real-time execution of spiking neural networks applied to neural cognitive applications
  
  Author: VALLEJO MANCERO, BERNARDO JAVIER
  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: 01/10/2024
  Deposit END date: 14/10/2024
  Thesis director: MADRENAS BOADAS, JORDI | ZAPATA RODRÍGUEZ, MIREYA PATRICIA
  Committee:
       PRESIDENT: ITUERO HERRERO, PABLO
       SECRETARI: MORENO AROSTEGUI, JUAN MANUEL
       VOCAL: MARGARIT TAULÉ, JOSEP MARIA
  Thesis abstract: This thesis contributes to the field of neuromorphic hardware. In particular, to the significant improvement of a scalable hardware architecture, named Hardware Emulator of Evolvable Neural Spiking Systems (HEENS), for the real-time execution of spiking neural networks (SNNs) in cognitive applications. SNNs are neural networks inspired by the biological activity of the brain, designed to process discrete temporal events, offering improved capabilities for handling temporal data as well as local plasticity, thus exhibiting greater energy efficiency compared to traditional neural networks.The HEENS architecture is implemented on several AMD (Xilinx) Zynq hardware platforms, which combine ARM processing cores with programmable logic (FPGAs), known for their high flexibility and parallelism in the execution of different neural models. One of the key achievements of this thesis is the optimization of the architecture to reduce latency, minimize resource usage, increase processing capacity, overcome previous architectural issues, and improve adaptability to various cognitive applications, such as sensory processing and pattern recognition.The results obtained can be divided into architectural contributions and experimental results in real applications. In the first part, this work improves the synaptic mapping capability, develops new system configuration mechanisms, and introduces interaction with external sensors.The enhanced system integrates an HDMI interface, demonstrating real-time visualization of neural activity and the neural and synaptic parameters of the SNN allows continuous monitoring without affecting system performance. This real-time monitoring capability has been tested in multiple experiments, where a precise representation of neural activity was observed on a 1 ms time scale, considered to be real-time, with support to other time scales, both faster or slower. The use of HEENS in physical sensor processing is highlighted, where it was proven that the architecture can adapt in real-time to changes in input signals, making it an ideal platform for applications in robotics and autonomous systems.Regarding testbenches and applications, significant results are presented in the implementation of cognitive applications using HEENS. In handwritten digit recognition, the architecture showed high accuracy using SNN models with synaptic plasticity, achieving good performance in terms of processing time and energy consumption compared to other existing solutions. Another key result is the hardware emulation of neuronal cultures, comparing the behavior of simulated neural networks in vitro, in silico, and in duris silico (physical hardware). The experiments showed that HEENS is capable of faithfully replicating the behavior and statistical properties observed in real neuronal cultures, opening new possibilities for research in neuroscience and biomedicine.Finally, the thesis concludes that the HEENS architecture not only offers a flexible and efficient environment for the research and development of SNN but also enables its implementation in real-world applications demanding real-time processing with good energy performance. The advances achieved in this work represent an important step toward the creation of next-generation scalable neuromorphic systems capable of efficiently emulating complex cognitive functions.
  

DOCTORAL DEGREE IN ENVIRONMENTAL ENGINEERING

• ARFELIS ESPINOSA, SERGI: Life cycle assessment as a tool for the industrialisation of chemical and mechanochemical processes
  
  Author: ARFELIS ESPINOSA, SERGI
  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 ENVIRONMENTAL ENGINEERING
  Department: Department of Civil and Environmental Engineering (DECA)
  Mode: Article-based thesis
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: FULLANA PALMER, PERE | BALA GALA, ALBA | MALPARTIDA GARCIA, IRENE
  Committee:
       PRESIDENT: MAIRELES, PEDRO JESÚS
       SECRETARI: DELGADO AGUILAR, MARC
       VOCAL: CANALES MUÑOZ, ROBERTO IVAN
  Thesis abstract: The chemical sector is a $4 trillion global business and a major employer, with chemicals present in almost all manufactured products. Increasing investment and the chemical industry's innovative capacity to provide safe and sustainable products will be vital in offering new solutions and supporting the ecological transition of our economy and society. Multiple approaches and tools have been developed to assist chemists in the development, design, and application of chemical products. The Life Cycle Assessment (LCA) approach, applied to the design of chemicals and processes, has helped scientists examine environmental impacts from a life cycle perspective. It provides a global view of environmental burdens, covering a broad set of environmental indicators such as Global Warming, Primary Energy Consumption, Water Use, Land Use, or Resource Depletion.This thesis is related to the application of LCA to the industrialization of chemical and mechanochemical processes. The first article presents a literature review of LCA for chemical processes. The second article is another review on mechanochemical processes. Chemistry and mechanochemistry are leading sectors in the application of LCA, but their methodology is still scarce. The development of these articles aims to provide a guide for the advancement of these topics. Additionally, the thesis continues with the evaluation of innovative technologies for chemical processes: production of calcium zincate as an ingredient for rechargeable batteries, cellulose extraction from wood chips, or nicotine extraction from tobacco leaves, for instance.It has been concluded that the choice of raw material is often the main source of environmental impact in a chemical process. Furthermore, mass and energy balances, as well as the type of energy supplied to power the process, are of great importance as part of the life cycle inventory. When selecting the functional unit (FU) for industrial chemical processes, where a given amount of product must be supplied within a given time frame, special attention must be paid. Although it falls outside the scope of cradle-to-gate LCA practice, variables such as reaction residence time can result in the final product having more service units or more functions. Therefore, this should be considered valuable additional information when deciding between alternatives. The LCA result with an FU that depends solely on mass does not account for this. Several chemical LCA studies already conduct assessments using flow rate as an FU. Another example is the consideration of module D within EN 15804:2012+A2:2019 for the inclusion of information outside the cradle-to-gate scope in LCAs of construction products.Moreover, the scalability of material flows from the laboratory scale, where data is obtained, to the pilot or industrial scale, where the process will be applied, is of crucial importance. For this purpose, different frameworks based on thermodynamic equations, as well as process modeling and simulation tools, have been used throughout the thesis. For instance, it has been observed that energy optimization from the lab to the industrial scale is around 20% on average, reaching maximum values of 90% for some equipment, such as the reactor used in Deasyl's laboratories. Finally, in LCA comparisons, an environmental impact evolution study is conducted, taking into account forecasts for electricity mixes in the coming years according to reports from the European Green Deal to interpret how the results will behave in the future.
  
• RUIZ DE ALEGRIA SALA, ALBA: Effective ventilation solutions for educational environments: balancing health, comfort, and sustainability in a post-pandemic scenario
  
  Author: RUIZ DE ALEGRIA SALA, ALBA
  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 ENVIRONMENTAL ENGINEERING
  Department: Department of Civil and Environmental Engineering (DECA)
  Mode: Normal
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: CANALS CASALS, LLUC | MACARULLA MARTÍ, MARCEL
  Committee:
       PRESIDENT: GANGOLELLS SOLANELLAS, MARTA
       SECRETARI: QUENTIN PÉAN, THIBAULT
       VOCAL: NERI, MANUELA
  Thesis abstract: Indoor air quality (IAQ) and thermal comfort are critical in educational buildings, as poor conditions have been linked to reduced cognitive performance, higher absenteeism and long-term health effects. The COVID-19 pandemic further underscored these issues, especially in naturally ventilated environments, which comprise 93% of schools in tropical or subtropical locations. Initially, schools and universities transitioned to remote learning to curb the spread of the virus. When in-person learning resumed, enhanced ventilation protocols and awareness campaigns emphasized the importance of occupants' role in maintaining IAQ in naturally ventilated environments. However, several critical questions emerged: Were short-term awareness campaigns effective in fostering long-lasting changes in ventilation behaviour? Could natural ventilation alone consistently meet air quality standards without compromising thermal comfort? As the pandemic subsided, these challenges highlighted the need for resilient solutions that could not only mitigate immediate health risks but also promote healthier, more adaptable indoor environments in the face of future public health challenges.This thesis addresses these issues through a comprehensive investigation of ventilation strategies, thermal comfort, and IAQ in naturally ventilated educational buildings during and after the COVID-19 pandemic. The study involved extensive measurement campaigns in classrooms at various academic recording variables such as CO₂ concentrations, air and mean radiant temperatures, relative humidity and air velocity. These campaigns aimed to assess both the effectiveness of natural ventilation and the sustainability of behaviour changes prompted by short-term awareness initiatives. In a first stage, a sensitivity analysis evaluates the impact of assuming certain variables when estimating thermal comfort using PMV and adaptive models from ASHRAE 55, ISO 7736, EN 16798 standards. The findings suggest that simplified thermal comfort models can provide reliable estimates when benchmarked against estimations that incorporate globe sensor measurements of mean radiant temperature (accuracy ±2 °C). This reduces the need for continuous monitoring of variables like mean radiant temperature and air velocity, streamlining thermal comfort assessments in educational settings.Regarding IAQ during and after COVID-19, the study found that natural ventilation alone often failed to meet recommended CO₂ thresholds, primarily due to the trade-off between maintaining thermal comfort and achieving adequate air exchange. Although intensive awareness campaigns led to short-term behavioural changes, the initial improvements in IAQ were short-lived, with CO₂ concentrations rising again as awareness waned. Alternative strategies, such as reduced classroom occupancy or online learning, posed logistical challenges and risked exacerbating educational inequalities. These findings emphasize the need for mechanical ventilation as the most reliable method for improving IAQ and controlling infection spread. However, mechanical systems are energy-intensive, necessitating more efficient alternatives. To address this issue, this thesis focuses on demand-controlled ventilation systems due to their potential for reducing energy demand. Specifically, it examines the characteristics that monitored data must meet for effective calibration of the models used in the control. For this purpose, grey-box models developed from 47 measurements data are used. The results show that the models are most accurate when changes in occupancy and ventilation range between 15 and 20%, and when the coefficient of variation of CO₂ is at least 0.3. These conditions enable dynamic control of ventilation systems, optimizing performance while adapting to fluctuating conditions. Additionally, the potential integration of CO₂ from classroom air into greenhouse crops was explored, revealing promising synergies.
  

DOCTORAL DEGREE IN MARINE SCIENCES

• ROMERO MARTIN, RUT: Confronting coastal hazards: Contributions to climate change adaptation strategies and planning in the Mediterranean.
  
  Author: ROMERO MARTIN, RUT
  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: Department of Civil and Environmental Engineering (DECA)
  Mode: Normal
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: JIMENEZ QUINTANA, JOSE ANTONIO
  Committee:
       PRESIDENT: CIAVOLA, PAOLO
       SECRETARI: MÖSSO ARANDA, OCTAVIO CESAR
       VOCAL: DEL RIO RODRIGUEZ, LAURA
  Thesis abstract: Coastal areas are highly vulnerable to climate change, with rising sea levels and storms threatening ecosystems and human activities. The Mediterranean coast, a densely populated and economically important region, faces particularly severe impacts. This study develops adaptation strategies to support flexible and effective management of these coastal challenges, focusing on the Spanish Mediterranean coast, which is especially at risk due to its high population density, dependence on beach tourism, and vulnerable geomorphology. These factors have created an urgent need for adaptation strategies that mitigate both short- and long-term risks. One of the key contributions of this work is the development of a Compound Risk Index (CRI), which classifies coastal zones based on hazards, vulnerability, and exposure to climate risk. The index shows that around 60% of coastal municipalities along 1,100 km of the Spanish Mediterranean are at risk due to the high vulnerability of the coastlines, mainly from their geomorphology and limited space for natural beach migration. The work proposes two key adaptation strategies: managed retreat to enhance the natural resilience of beaches, which involves evaluating the need for Accommodation Space to allow inland migration, and another strategy focused on maintaining the recreational function of the beaches. This second strategy involves determining the Beach Carrying Capacity (BCC) and implementing artificial beach nourishment. An economic cost-benefit analysis has been conducted for the beach nourishment strategy. This highlights the need for adaptable, long-term management that balances environmental protection with sustaining coastal recreation and tourism. In addition, the research provides a detailed analysis of Storm Surge impacts, particularly in vulnerable areas like the Ebro Delta, where the risk of flooding is high due to low-lying terrain. The study highlights the need for precise flood modeling and proactive planning to mitigate future risks, ensuring that coastal areas remain resilient under uncertain climate conditions. Finally, the thesis compares projections from the Probabilistic Coastal Recession (PCR) model with those derived from the traditional Bruun rule, revealing important differences in erosion projections in key areas like the Llobregat Delta and Maresme coast. These findings offer valuable insights for designing localized adaptation strategies tailored to the specific characteristics of each coastal stretch.
  

DOCTORAL DEGREE IN MATERIALS SCIENCE AND ENGINEERING

• DE LA CRUZ JESUS, LUCIA GUADALUPE: Multifunctional eco-friendly aerogel composites for thermal insulation and fire resistant applications.
  
  Author: DE LA CRUZ JESUS, LUCIA GUADALUPE
  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 MATERIALS SCIENCE AND ENGINEERING
  Department: Department of Materials Science and Engineering (CEM)
  Mode: Article-based thesis
  Deposit date: 01/10/2024
  Deposit END date: 14/10/2024
  Thesis director: SANCHEZ SOTO, MIGUEL ANGEL | ABT, TOBIAS MARTIN
  Thesis abstract: Replacing petroleum-based polymers with natural alternatives requires overcoming the limitations of their thermal and mechanical properties, as well as the inherently low fire resistance of the biomass from which they are derived. A common method for improving thermal insulation is through the use of porous systems such as technical foams. Aerogels, as highly porous materials, are lightweight and have low thermal conductivity, making them effective barriers for this purpose. However, the challenge remains in finding a solution where all the aforementioned properties are fully optimized. This thesis aims to demonstrate that by using environmentally friendly materials and processes, it is possible to create multifunctional aerogels with optimized properties, positioning them as viable alternatives, among others, to conventional foams.Polyvinyl alcohol (PVA), a biodegradable synthetic polymer, was initially studied with the introduction of alginate and tannic acid (TA) as natural modifiers and clay playing the role of structural scaffold. The hydrogen bonding between the polar groups of the components resulted in a nearly tenfold improvement in the mechanical properties as compared to pure PVA aerogels. The addition of NaOH was necessary to overcome the high hydrogen bonding attraction between TA and PVA that causes a fast precipitation of a solid which hindered gel formation. The PVA aerogel matrix was further cross-linked using calcium and borate ions, leading to an additional enhancement in mechanical performance, along with increased thermal stability and fire resistance, with the peak of heat release decreasing five-fold with respect to PVA.Gelatin—an abundant and cost-effective protein—was utilized as a novel system for developing optimized aerogel composites. Tannic acid played a crucial role in establishing strong bonds with the active sites of gelatin, a process that was carried out under alkaline conditions to stabilize the hydrogel complex. This approach resulted in exceptionally strong aerogels, achieving up to a 15-fold increase in yield stress. The protective action of well-dispersed nanoclay particles enhanced the pyrolytic decomposition and charring effects of tannic acid, imparting excellent flame-retardant properties to the aerogels. Although gelatins’ highly hydrophilic nature posed an initial challenge, a simple dip-coating treatment with polydimethylsiloxane and SiO2 nanoparticles effectively conferred superhydrophobic surfaces.Finally, the performance of modified ammonium alginate/clay/tannic acid composites was studied based on the orientation induced during the freeze-drying process. Alginate, a naturally abundant polysaccharide, was chosen as the base polymer for the aerogels due to its high fire resistance and the release of nitrogen upon heating, which reduces the amount of combustible gases. Orientation and crosslinking were key steps in enhancing the mechanical properties, achieving values as high as 305 MPa for Young’s modulus and 7 MPa cm³/g for yield strength, placing these systems among the highest reported in the literature. Thermal conductivity fit well with existing model predictions, increasing in axially oriented samples due to heat convection contribution through large vertical pores. Thermal stability and fire resistance were significantly improved by the addition of tannic acid, resulting in a minimal peak heat release of just 21 kW/m² and no detectable flame.New types of eco-friendly composite aerogels with an ultralight, porous structure have been developed. They were successfully fabricated using freeze-drying and post-cross-linking techniques, achieving an excellent balance of mechanical strength, thermal stability, and fire retardancy. In summary, this work demonstrates that bio-based and biodegradable aerogels can serve as a viable approach when seeking greener alternatives with properties comparable to current traditional foam-like materials.
  

DOCTORAL DEGREE IN MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING

• CRUPANO, WALTER: Procesamiento mediante extrusión de material del termoplástico híbrido PLA/PHB: caracterización mecánica
  
  Author: CRUPANO, WALTER
  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 MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING
  Department: Department of Mechanical Engineering (EM)
  Mode: Normal
  Deposit date: 07/10/2024
  Deposit END date: 18/10/2024
  Thesis director: TRAVIESO RODRIGUEZ, JOSE ANTONIO | ADROVER MONSERRAT, BÀRBARA
  Committee:
       PRESIDENT: GÓMEZ GRAS, GIOVANNI
       SECRETARI: NESCOLARDE SELVA, LEXA DIGNA
       VOCAL: ABAD ROLDAN, MANUEL DAVID
  Thesis abstract: In this thesis, the mechanical behavior of parts manufactured by Material Extrusion Modeling (MEX) has been evaluated, using a copolimer of polylactic acid (PLA) and polyhydroxybutyrate (PHB), commercially known as NonOilen. The objective was to analyze how the addition of PHB affects the mechanical properties of pure PLA and how the printing parameters influence these properties. To do so, compression and rotational fatigue tests were performed, using the design of experiments methodology to optimize these parameters.In addition, the performance of NonOilen was compared with pure PLA and with Timberfill, a PLA-wood composite material. The viscoelastic behavior of NonOilen was also studied, and the experimental data were adjusted to a viscoelastic model based on a three-term Prony series, in order to evaluate its influence on the apparent Young's modulus.The results showed that, although the addition of PHB reduces the stiffness and strength of the material compared to pure PLA, it improves its impact resistance and decreases fragility. Optimizing printing parameters such as extruder diameter and infill density was critical to maximizing the mechanical performance of the material. The design of experiments allowed identifying optimal printing configurations for different applications. For example, to achieve high compressive strength, a small layer height and a large extruder diameter were the best configuration, while for higher fatigue strength, higher layer heights and lower printing speeds were recommended.The study of the viscoelastic behavior of NonOilen underlined the importance of selecting the appropriate printing orientation to maximize the durability of the parts. As for the comparison with pure PLA, it demonstrated greater strength in compression and fatigue tests, with a 35% higher Young's modulus and a 40% higher yield strength than NonOilen. However, the addition of PHB made NonOilen more impact resistant and less brittle, being more appropriate for applications requiring energy absorption. In the rotary fatigue tests, the Wöhler curves of both materials showed differences due to the copolymer structure of NonOilen, whose fatigue resistance was lower than that of pure PLA. Still, its higher resistance to deformation makes it competitive in applications where toughness is a priority.When comparing NonOilen with Timberfill, it was observed that NonOilen surpassed Timberfill in stiffness and strength, presenting a 20% higher Young's modulus and a 35% higher yield strength. However, Timberfill resisted more load cycles in the rotary fatigue tests, suggesting that this material is more suitable for situations that demand greater durability under cyclic loads.In summary, although pure PLA presented better results in stiffness and strength, the combination of PHB and PLA in NonOilen offers an interesting balance, improving impact resistance and reducing brittleness. Optimizing printing parameters is essential to adjust the material properties to the specific needs of each application.Finally, the work carried out in this thesis has allowed not only to characterize the mechanical properties of NonOilen in comparison with other commercial materials, but also to highlight its viability as an ecological and competitive alternative, especially in applications where biodegradability and impact resistance are prioritized. The improvements introduced in the methods of viscoelastic analysis and in the 3D printing optimization process have contributed to a better understanding of the behavior of the material under different conditions of use.
  
• KARIMZADEGAN, KAVOOS: Fluidic Oscillator Numerical Modelling Considering Dimensional Modifications
  
  Author: KARIMZADEGAN, KAVOOS
  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 MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING
  Department: Department of Fluid Mechanics (MF)
  Mode: Change of supervisor
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: BERGADÀ GRANYÓ, JOSEP MARIA | MIRZAEI, MASOUD
  Committee:
       PRESIDENT: CASALS TERRE, JASMINA
       SECRETARI: GONZÁLEZ CASTRO, JOSEP RAMON
       VOCAL: HERRERO SABARTÉS, JUAN
  Thesis abstract: Fluidic Oscillators (FO) may significantly improve flow mixing and cooling. However, they are mostly used in Active Flow Control (AFC) applications, where the pulsating flow they generate interacts with the boundary layer to typically postpone its separation. Before using any FO in an application, it is crucial to analyze the frequencies and amplitudes it may produce based on the incoming mass flow and its dimensions. The current work focuses on explaining this particular aspect in a somewhat innovative FO setup. We have preformed a numerical study of a conventional FO arrangement using both two-dimensional (2D) and three-dimensional (3D) approaches. Upon comparing the 3D and 2D data and analyzing the primary disparities, we made adjustments to the internal dimensions of the FO to assess the impact on its dynamic performance. The current findings clarify which are the internal dimensional alterations that provide greater output frequencies and amplitudes in the velocity field. An effort is made to examine the source of the self-sustained oscillations. According to the results of the numerical investigations, the dimensional modifications influenced the reverse flow inside the feedback channels, increasing/decreasing it at the feedback channels outlets, which had a clear effect on the frequency and on the operation of the device. When evaluating the forces acting on the jet as it enters the mixing chamber, the pressure momentum (pressure force) appears under all conditions studied, to be several times higher than the mass flow one, from which it can be concluded that this fluidic oscillator is pressure driven. As expected, the increase of the incoming flow Reynolds number, has a direct relation on the fuidic oscillator outlet frequency. The present research establishes for the first time a relation between the reverse mass flow in the feedback channels with the fluidic oscillator outlet frequency, the higher the feedback channel mass flow, the smaller the fluidic oscillator outlet frequency. Also has also been stated that, the 2D-CFD simulations, overestimated the feedback channel reverse flow.
  
• MORALES AVALOS, JORGE EDUARDO: Modeling of orthopedic surgeries using advanced biomechanical computational techniques
  
  Author: MORALES AVALOS, JORGE 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 MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING
  Department: Department of Mechanical Engineering (EM)
  Mode: Normal
  Deposit date: 30/09/2024
  Deposit END date: 11/10/2024
  Thesis director: SERRANCOLÍ MASFERRER, GIL | SÁNCHEZ EGEA, ANTONIO JOSÉ
  Committee:
       PRESIDENT: GILL, RICHIE
       SECRETARI: NOAILLY, JEROME BERNARD
       VOCAL: PELFORT LOPEZ, XAVIER
  Thesis abstract: This dissertation deals with the modeling and simulation of orthopaedic surgeries with the help of computational biomechanical techniques. These orthopaedic conditions are characterized by their geometry and mechanical interactions and need to be translated properly to a virtual environment. Besides engineering simulations such as stress and strain calculations, pre-surgery planning, development of patient-specific treatments and innovation on new surgical trends are some of the benefits that may result from the development of accurate and reliable orthopaedic in-silico models. To provide detailed digital models for the different fields of application, a strong collaboration with surgeons experts on the field has been considered. New knee orthopaedics surgical opportunities have appeared in the last decades oriented to minimizing the effect of diseases like \acrfull{koa}, such as proximal fibular osteotomy (PFO) and computational modeling might help to investigate their biomechanics in-silico. This work focus on the systematic development of in-silico PFO models that can be later on used to create proper and reliable virtual representations of patient-specific surgical treatment response.A major challenge for correctly representing anatomical models for virtual environments is developing a consistent data acquisition methodology and model reconstruction methods. By using \acrfull{fem}, generating accurate mechanical models of orthopaedic systems for a specific condition may provide a reliable baseline for all future virtual modeling approaches. Therefore, numerical simulations have been formulated based on real-world clinical case scenarios provided by our medical collaborators and partners. Mechanical models have be hence not only virtually investigated, but a comparison with respect to patient-specific treatments has been made. The biomechanical response of human joints, with particular interest on the knee, before and after surgical interventions has been herein investigated. These surgical interventions were pre-planned to provide the healthcare needed to the patients without this research work affecting any required medical care. The novel contribution of this investigation is the quantitative analysis of the impact of PFO on the biomechanics of the knee joint. The results provide mechanical evidence that PFO can effectively redistribute and homogenize joint stresses, while also repositioning the \acrfull{cop} towards the center of the knee, similar to what is observed post \acrfull{hto}. The findings propose PFO as a potentially viable and simpler alternative to conventional surgical methods for managing severe KOA, specifically in patients with medial compartment genu-varum.Furthermore, the computational techniques implemented will be optimized to produce the best possible results in the most efficient way. This research also marks the first application of FEMs that may support one of the underlying biomechanical theories of PFO, providing a foundation for future clinical and in-silico studies.
  

DOCTORAL DEGREE IN NUCLEAR AND IONISING RADIATION ENGINEERING

• CURCOLL MASANES, ROGER: Enhancing greenhouse gases flux estimates through improved atmospheric radon monitoring using the Radon Tracer Method
  
  Author: CURCOLL MASANES, ROGER
  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: Institute of Energy Technologies (INTE)
  Mode: Normal
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: VARGAS DRECHSLER, ARTURO | GROSSI, CLAUDIA
  Committee:
       PRESIDENT: FONT GUITERAS, LLUÍS
       SECRETARI: PINO GONZALEZ, DAVID
       VOCAL: HERNANDEZ CEBALLOS, MIGUEL ANGEL
  Thesis abstract: Anthropogenic greenhouse gas (GHG) emissions are the main drivers of global warming and climate change. Despite advancements in sources quantification, uncertainties persist in the quantification of carbon dioxide (CO2) and methane (CH4) emissions, both biogenic and anthropogenic. The Paris Agreement has heightened the need to reduce these uncertainties through independent observations and methodologies.This work has focused on improving the estimation of GHG fluxes through the application of the Radon Tracer Method (RTM). This methodology combines high-quality measurements of atmospheric radon and of the GHGs of interest with radon flux data from the footprint of the stations to quantify GHG fluxes. Radon fluxes are obtained by combining radon flux maps with atmospheric transport models.In the first part of the thesis, a high-sensitivity monitor (ARMON v2) for measuring atmospheric radon was developed, calibrated, and compared with other monitors. The ARMON v2 is an improved version of a previous monitor designed by the Institute of Energy Techniques (INTE). Its detection principle is based on the deposition of 218Po+ particles on a semiconductor detector by applying a voltage of 10kV in the detection volume. The ARMON v2 was designed to meet the necessary requirements for measuring radon at atmospheric stations and to serve as a reference monitor for the in-situ calibration of other devices. It is more robust, portable, and easier to use than its predecessor and includes software that allows full control and real-time data visualisation.The detection efficiency of the new ARMON v2 was obtained both theoretically and experimentally. Theoretically, the collection of 218Po+ particles on the detector surface was simulated. Experimentally, it was calibrated in radon chambers at the INTE and PTB (Germany), obtaining efficiency values of 0.0057 s-1 Bq m-3 and 0.0059 s-1 Bq m-3 respectively. Uncertainty analysis gave values below 10% for radon concentrations above 5 Bq m-3. Additionally, the response of the ARMON v2 was compared with other devices at atmospheric stations in France and Germany. The ARMON v2 will be commercialised by Radonova, a company to which the usage licence has been granted.In the second part, the atmospheric transport model Flexpart-WRF and the radon flux maps developed under the traceRadon project, both used in the subsequent application of the RTM, were validated. Validation was carried out by modelling radon concentration, combining Flexpart-WRF simulations with radon flux maps at three stations: SAC (near Paris, France), DEC (Ebro Delta, Spain), and BII (Barcelona, Spain). The latter two present complex terrain due to their proximity to the sea and sea breeze regimes.In the final part, RTM was applied at DEC and BII. At DEC, CH4 fluxes associated with rice cultivation were quantified, while at BII, metropolitan emissions of CO2 and CH4 were measured. The results at DEC show a high correlation with previous studies conducted using accumulation chambers. Moreover, they reveal that inventories such as EDGAR do not adequately account for agricultural emissions from the Ebro Delta. At BII, the RTM results were compared with EDGAR for CH4 and with four inventories for CO2. The RTM-estimated fluxes align with inventories in terms of low seasonality and magnitude, but variability among inventory values makes their evaluation challenging.The application of RTM, together with atmospheric transport models such as Flexpart-WRF, offers an alternative and independent methodology for quantifying and observing the seasonal variability of GHG fluxes in complex areas with anthropogenic emissions. Furthermore, the need to improve the precision of radon flux maps to increase the reliability of estimates is emphasised.
  

DOCTORAL DEGREE IN OPTICAL ENGINEERING

• GAL, EYAL: Clinical comparison of two specialty soft lenses for Keratoconus
  
  Author: GAL, EYAL
  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 OPTICAL ENGINEERING
  Department: Department of Optics and Optometry (OO)
  Mode: Normal
  Deposit date: 30/09/2024
  Deposit END date: 11/10/2024
  Thesis director: GANTZ, LIAT
  Committee:
       PRESIDENT: SHNEOR, EINAT
       SECRETARI: LAMARCA MATEU, JOSE
       VOCAL: TRAVE HUARTE, SONIA
  Thesis abstract: Due to advanced diagnostic instruments for detection of early-stage keratoconus (KC), and procedures that halt its progression such as corneal collagen cross-linking (CXL), optometry clinics are now seeing less severe cases of irregular corneas. As a result, optometrists are treating earlier stages of KC, and contact lens (CL) solutions for earlier stages of the disease are warranted. This thesis comprehensively evaluated the utility of two specialty soft lenses for KC of varying diameters and thicknesses in 40 eyes (N=20, mean age: 39±10, range: 23-55 yrs.) with KC grade 1 or 2 (based on Amsler-Krumeich) using a randomized, crossover, prospective longitudinal (up to one year follow-up) clinical design. The visual quality, contrast sensitivity, higher order aberrations (HOA), subjective satisfaction and wearer preference were compared between SoftK2 and Semi-scleral SoftK lenses. Objective visual outcomes were also compared with those obtained with gold-standard RGP lenses. Both soft lens designs significantly improved high contrast visual acuity (SoftK2 0.05±0.07, Semi-scleral SoftK 0.10±0.09LogMAR) compared with the habitual state (0.23±0.27 LogMAR). SoftK2 lenses provided low contrast VA 0.29±0.15 LogMAR), high contrast VA (0.04±0.06 LogMAR), contrast sensitivity (1.55±0.12 Log units), and HOA similar to GP lenses (low contrast visual acuity 0.27±0.17 Log MAR, high contrast visual acuity 0.07±0.07 LogMAR and contrast sensitivity 1.55±0.10 LogCS units). With low contrast, Semi- scleral SoftK did not show statistical significance compered to SoftK2 and from habitual state (0.40±0.2 Semi-scleral SoftK 0.52±0.3 habitual). No adverse events, limbal or conjunctival redness, papillary reaction, unusual appearances, or patient complaints requiring clinical action were noted at any of the follow-up visits with either lens type. The SoftK2 lens was preferred by 75% of the participants and had fewer participants with reported adverse events of dryness sensation after two weeks of wear. More participants continued its use over a period of 12-month with SoftK2 (7 participants were still using SoftK2 after 12 months, while no one was with Semi- scleral SoftK).SoftK2, Semi-scleral SoftK, and scleral GP lenses showed significant improvements of coma, trefoil, and tetrafoil HOAs compared to the uncorrected state, without significant differences between the lenses. SoftK2 and Semi-scleral SoftK lenses induced corneal swelling with clinically significant values in the periphery (7%-9% higher than the habitual state), which implies careful monitoring of eventual physiological adaptation changes to sustained hypoxia induced by the lens over time.The soft lenses were expected to only partially correct the refractive error of the KC participants leaving a small residual astigmatism. Since no clinical test currently exists to detect alterations in visual perception due to residual uncorrected astigmatism, an early part of the dissertation, was devoted to examining the utility of a novel test developed by Prof. Arnold Wilkins (UK), theWilkins Egg and Ball Test (WEBT) to address this question. The results of the WEBT were compared between three cohorts: 32 normal participants (mean age: 24±5) under baseline and induced cylinder ,22 keratoconic eyes (N=13, mean age: 36±12) and 23 astigmatic participants (mean age: 36±12). The WEBT was found to be sensitive to overall blur and not to residual astigmatic blur. Its measurements with Soft K2 compared with Semi-scleral SoftK lenses were not significantly different.We conclude that specialty soft lens designs for keratoconus are a viable alternative for KC patients with Stage 1 or 2 in terms of visual quality and tolerance. However, more research is needed to evaluate the long term eventual physiological implications of induced corneal swelling.
  
• SUNYER GRAU, BERNAT: Study of strabismus causes and management: the efficacy of vision therapy in the treatment of central stabismus
  
  Author: SUNYER GRAU, BERNAT
  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 OPTICAL ENGINEERING
  Department: Department of Optics and Optometry (OO)
  Mode: Normal
  Deposit date: 04/10/2024
  Deposit END date: 17/10/2024
  Thesis director: QUEVEDO JUNYENT, LUISA JESUS | RODRÍGUEZ VALLEJO, MANUEL
  Committee:
       PRESIDENT: CERVIÑO EXPÓSITO, ALEJANDRO
       SECRETARI: ARGILÉS SANS, MARC
       VOCAL: MOLINA MARTÍN, AINHOA
  Thesis abstract: Strabismus is a deviation of the visual axes that prevents bifoveal fixation. It is a relatively common condition that affects between 2-6% of the population. The presentation of strabismus can vary greatly from one person to another, as it can differ in the direction of the deviation, its magnitude, whether it is constant or intermittent, unilateral or alternating, concomitant or incomitant, among others. Furthermore, ocular deviation can coexist with equally diverse sensory adaptations. The wide range of forms that strabismus can take suggests that it is not a single entity, but rather a possible consequence of multiple underlying conditions.The causes of strabismus can arise from problems in any of the structures involved in vision and oculomotor control. From the eye and its annexes, peripheral origin, to alterations in the brain, central origin. Strabismus of peripheral origin is generally well-defined but is the least frequent. It is usually caused by problems in the orbit, the extraocular muscles (EOMs), or their innervations, either due to genetic alterations or acquired defects. Most cases of strabismus remain poorly understood, and it is believed that their causes have a central origin: the result of abnormal development of the neural networks involved in the visual and oculomotor systems.The treatment of strabismus is traditionally based on optical correction, observation, and/or surgery of the extraocular muscles. When the deviation persists, eye surgery is the primary treatment option. Although it is a procedure frequently performed in ophthalmic practice, it continues to be debated regarding which surgical procedure is the most effective and what is the optimal age for intervention. Moreover, the criteria for a successful outcome in EOM surgery vary greatly between studies. An alternative treatment option for strabismus is visual therapy, a series of sequential and progressively more challenging exercises designed to improve binocular control and fusion. Visual therapy is used in the treatment of visual dysfunctions. However, scientific evidence supporting its use in strabismus is limited.The main objective of this thesis is to shed light on the causes of strabismus and its relationship with treatment. To do this, we conducted a narrative review on the etiology of concomitant strabismus, where we concluded that most evidence points to a central cause rather than a peripheral one, meaning without significant alterations of the EOMs. We also conducted a review on the success of surgery and whether the causes of strabismus are considered in the surgical treatment of intermittent exotropia. The conclusions of this study are that the causes are not considered, and the criteria for surgical success vary greatly between studies, being almost exclusively based on motor aspects, overlooking sensory aspects. The third study consists of the clinical case of a patient with recurrent infantile esotropia who had undergone six EOM surgeries as a child and was successfully treated with visual therapy in adulthood. Finally, we designed a pilot program aimed at helping visual health professionals in decision-making regarding the management of patients with strabismus. The program takes into account the data collected during the visual examination, both in optometric tests and anamnesis, and based on that, provides information on the pros and cons of different treatment alternatives, the expected prognosis if opting for visual therapy, and offers ideas for exercises and tips for performing visual therapy.
  
• TURULL MALLOFRÉ, AINA: Study of the accommodation during refraction: Development of new methodologies for accurate refractions
  
  Author: TURULL MALLOFRÉ, AINA
  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 OPTICAL ENGINEERING
  Department: Department of Optics and Optometry (OO)
  Mode: Normal
  Deposit date: 02/10/2024
  Deposit END date: 15/10/2024
  Thesis director: ALDABA AREVALO, MIKEL | GARCIA GUERRA, CARLOS ENRIQUE
  Committee:
       PRESIDENT: ARTAL SORIANO, PABLO
       SECRETARI: VIÑUELA NAVARRO, VALLDEFLORS
       VOCAL: GONZALEZ MEIJOME, JOSE MANUEL
  Thesis abstract: Uncorrected refractive error is the main cause of visual impairment worldwide, with its incidence being even bigger in developing countries, where access to eye care is severely limited, mainly due to a shortage of clinicians. Currently, the gold standard for assessing refraction and prescribing glasses is subjective refraction, which stands out for considering the psychophysical response of the subjects and for incorporating a series of steps to properly control accommodation. However, this procedure requires a trained clinician. Automated systems that do not require trained professionals are a potential solution to the shortage of clinicians. Unfortunately, existing systems and recently developed technologies are still not satisfactory enough to perform at the same level as the gold standard. The two main challenges with these technologies are the poor control of accommodation and that some of them do not consider the subject’s perception.This thesis aims to study accommodation during refraction procedures and to propose a methodology capable of retrieving refraction without the need for a clinician. The thesis is divided into four studies. The first study centers on the validation of a system capable of monitoring accommodation in real time. Using a custom-developed Hartmann-Shack aberrometer coupled to a phoropter, the system allows tracking the refractive state of the eye every 100 ms. The system was validated by analyzing the through-focus accommodative response. The results of this study show that the system is capable of successfully measuring the refractive state of the eye dynamically and the measurements are comparable to the ones reported in other studies.The second study explores the accommodative response during the fogging technique. It focuses on the impact of the power and time of application of fogging lenses on accommodation relaxation. Its results show that fogging lenses do provide some relaxation of accommodation, although high variability between participants was found, suggesting that there is no ideal formula that can suit all patients.The third study analyzes how accommodation and visual acuity behave during subjective refraction. Results show that accommodation is not at its minimum when reaching the subjective refraction value. The findings suggest that new automated technologies should not rely only on achieving the best visual acuity or the minimum accommodation. The final study explores the use of a machine learning algorithm to predict the spherical equivalent subjective refraction using as input data a through-focus accommodative response, optical quality metrics, and subject perception data. The machine learning models demonstrated promising performance, improving upon previously proposed methods. The study also highlights the need for new refraction systems to account for accommodation control and incorporate subjective feedback for more accurate prescriptions.In summary, the thesis made significant progress in understanding accommodation during refraction procedures and demonstrates the potential of machine learning for predicting subjective refraction.
  

DOCTORAL DEGREE IN PHOTONICS

• GONCALVES ROMEU, DANIEL: Novel approaches for quantum technologies with atoms and photons in free space
  
  Author: GONCALVES ROMEU, DANIEL
  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 PHOTONICS
  Department: Institute of Photonic Sciences (ICFO)
  Mode: Normal
  Deposit date: 10/10/2024
  Deposit END date: 23/10/2024
  Thesis director: CHANG, DARRICK
  Committee:
       PRESIDENT: GONZALEZ BALLESTERO, CARLOS
       SECRETARI: DE RIEDMATTEN, HUGUES
       VOCAL: GONZALEZ TUDELA, ALEJANDRO
  Thesis abstract: The rapid advancement of quantum technologies is currently pushing the boundaries of scientific and technological innovation. Among the various platforms for translating quantum theory into practical applications, photons have emerged as particularly strong contenders. Their inherent advantages, such as low decoherence and swift propagation, make them ideal carriers of quantum information for communication, computation and sensing purposes.However, the efficient manipulation and control of photonic quantum states presents significant challenges, often requiring the use of interfaces. In this Thesis, we investigate several novel approaches to engineer and control the properties of light using a very traditional system: trapped neutral atoms in free space. In Chapter 2, we introduce a novel method to observe and manipulate strong quantum interference effects between a few photons and a single free-space atom. The approach uses a Maltese-cross configuration, where two perpendicular pump and probe coherent fields drive the atom. Even for a weak atom-light coupling, we demonstrate that adjusting the relative pump-probe strength ratio and phase can simulate an artificially enhanced coupling efficiency for specific observables. In particular, we are able to engineer photon correlations from fully anti-bunched to extremely bunched states, and control the linear transmission properties in specific directions.In Chapter 3, we propose the combination of ordered atomic arrays and Rydberg Electromagnetically Induced Transparency (EIT) as a promising platform for quantum nonlinear optics. The spatial periodicity of the array enables precise control over photon scattering, reducing the inherent dissipation associated with traditional Rydberg EIT protocols. Using a two dimensional array, we design and characterize a single photon switch, where the storage of a single photon as a Rydberg excitation results in a strong change in the system's optical response. This switch can be used to implement a photon-photon gate with an error scaling with the Rydberg blockade radius as Rb^{-4}, potentially reaching gate efficiencies of up to 99% for realistic experimental parameters. Additionally, we model the optical properties of the array in the strong driving regime, where the system is multiply excited. In Chapter 4, we discuss a recent experiment that observed features of the Driven-dissipative Dicke phase transition in a driven elongated cloud in free space. This is unexpected, as the Dicke model typically involves an ensemble coupling identically to a single, lossy photonic mode, akin to an ensemble coupled to a cavity. Instead, a free-space ensemble interacts with a continuum of modes, encoding propagation effects. Solving a simple model to explain this behavior, based on the one-dimensional Maxwell-Bloch equations, we observe nonanalytic behavior in certain observables. However, a closer analysis reveals a significant spatial inhomogeneity in atomic properties. We thus argue that the free-space system does not undergo a phase transition but rather a “phase separation,” roughly speaking, between saturated and unsaturated regions. Beyond understanding the phase transition, we also elucidate under which conditions some properties of atoms in cavities can be mapped to atoms in free space.Together, the results in this Thesis represent a meaningful contribution towards better understanding phenomena associated to atom-light interactions in free space, and towards translating that knowledge into practical useful implementations.
  
• ORSINI, LORENZO: A Topological Nanophotonics platform based on hyperbolic phonon-polaritons
  
  Author: ORSINI, LORENZO
  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 PHOTONICS
  Department: Institute of Photonic Sciences (ICFO)
  Mode: Normal
  Deposit date: 10/10/2024
  Deposit END date: 23/10/2024
  Thesis director: KOPPENS, FRANK
  Committee:
       PRESIDENT: ALONSO GONZÁLEZ, PABLO
       SECRETARI: GARCÍA DE ABAJO, JAVIER
       VOCAL: GIANNINI, VICENZO
  Thesis abstract: Topological Nanophotonics is an emerging interdisciplinary field that offers a groundbreaking approach to control and manipulate light at the nanoscale. It combines principles from Topology, Photonics, and Nanotechnology to investigate the captivating behavior of light when confined to structures on the nanometer scale. A main goal of the community is to achieve topological edge states deeply confined below the diffraction limit. Despite promising theoretical and experimental progress, achieving these edge states in a Nanophotonic system remained elusive until now.This thesis is devoted to achieving these Topological edge states in a Nanophotonic system by combining several methods. First, we used natural hyperbolic materials to take advantage of their high-quality sub-diffraction-limit electromagnetic modes, known as hyperbolic phonon polaritons. Additionally, we employed an indirect patterning technique to fabricate nanophotonic devices, solving fabrication-induced issues and allowing for the precise control over the nanostructures. Finally, we characterized these Nanophotonic systems using scattering-type scanning near-field optical microscopy. Achieving deep subwavelength topological edge states required several foundational achievements:Quantitative Polaritonic Near-Field Analysis:Scattering-type scanning near-field optical microscopy is a powerful imaging technique for studying materials beyond the diffraction limit. However, interpreting near-field measurements poses challenges in mapping the response of polaritonic structures to meaningful physical properties. To address this, we developed a theory using the transfer matrix method to simulate the near-field response of 1D polaritonic structures. This efficient and accurate analytical theory maps the near-field response to well-defined physical properties, enhancing the understanding of near-field images and complex polaritonic phenomena. Advancing the Hyperbolic Platform:The physics underlying our hyperbolic platform was largely unexplored, leading to a significant gap in understanding the fundamental properties and control methods of indirect patterned hyperbolic materials. Our studies provided new insights into the behavior of hyperbolic phonon polaritons in indirect patterned systems. We achieved three key results: first, we gained new insights into the fundamental behavior of hyperbolic phonon polaritons providing a deeper understanding of their interactions within indirect patterned systems; second, we investigated indirect patterned hyperbolic nanocavities achieving record-breaking quality factors, approximately 80, while maintaining the mode volume five orders of magnitude smaller than the free-space excitation wavelength; and third, discovering that the coupling mechanism between cavities is radiative, significantly impacting the design of lattices and photonic crystals using indirect patterning. Achieving Deep Subwavelength Topological Edge States:We experimentally demonstrated deep subwavelength topological edge states by implementing a one-dimensional lattice based on the Su-Schrieffer-Heeger model. The topological edge state was confined in a sub-diffraction volume of 0.021μm³, four orders of magnitude smaller than the free-space excitation wavelength volume used to probe the system, while maintaining a resonance quality factor above 100.
  
• SUN, HUNG-WEI: X-ray absorption fine structure with attosecond soft X-ray pulses for condensed matter physics
  
  Author: SUN, HUNG-WEI
  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 PHOTONICS
  Department: Institute of Photonic Sciences (ICFO)
  Mode: Normal
  Deposit date: 26/09/2024
  Deposit END date: 10/10/2024
  Thesis director: BIEGERT, JENS
  Committee:
       PRESIDENT: CHALUS, OLIVIER
       SECRETARI: RUBIO VERDÚ, CARMEN
       VOCAL: BAUDISCH, MATTHIAS
  Thesis abstract: Understanding electron behavior in solids and their interactions with the lattice is crucial for exploring exotic phenomena in condensed matter. Traditional techniques often provide limited insights, focusing on either carriers or lattice structures independently. In contrast, X-ray absorption spectroscopy can simultaneously measure electrons and phonons, especially with the broadband continuum soft X-ray spectrum generated through high harmonic generation, facilitating simultaneous electron and phonon physics exploration. However, the strong absorption by solid-state samples necessitates extended measurement times. This thesis introduces the upgrades to the laser system and the attosecond soft X-ray beamline at ICFO, which enhance the detectable photon flux and improve the spectral resolution of the soft X-ray spectrograph. These advancements allow for detailed investigations of phase transition phenomena in materials such as Titanium diselenide (TiSe₂), providing an exceptional tool for understanding material properties at the microscopic level and paving the way for more precise studies of dynamic processes in condensed matter.
  

DOCTORAL DEGREE IN POLYMERS AND BIOPOLYMERS

• DE LAMA ODRÍA, MARÍA DEL CARMEN ELIZABETH: Applications of hydroxyapatite nanoparticles in the field of biomedicine
  
  Author: DE LAMA ODRÍA, MARÍA DEL CARMEN ELIZABETH
  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 POLYMERS AND BIOPOLYMERS
  Department: Department of Chemical Engineering (EQ)
  Mode: Normal
  Deposit date: 04/10/2024
  Deposit END date: 17/10/2024
  Thesis director: DEL VALLE MENDOZA, LUIS JAVIER | DEL VALLE MENDOZA, JUANA MERCEDES
  Thesis abstract: In the biomedical field, calcium phosphates have attracted attention due to their biocompatibility and bioactivity. They can be found in different individual phases (e.g., amorphous calcium phosphate, tricalcium phosphate, tetracalcium phosphate, octacalcium phosphate and hydroxyapatite), which vary in composition, Ca/P ratio, crystalline structure, degree of substitution, and properties. Among them, carbonated-low crystallinity and highly crystalline hydroxyapatite (CHAp and HAp, respectively) have principally been used for the design of targeted drug delivery systems (DDS) and implant coatings. As the study of the CHAp and HAp nanoparticles with modified morphologies or with different ionic substituents is commonly focused on the characterization of the systems or on the general analysis of the induced biochemical response, the main objective of the thesis was to extend the knowledge of their biomolecular impact in a variety of cell lines (e.g., tumoral or osteoblastic cell lines). On the first chapter, the potential of CHAp as a carrier for doxycycline (DOX) was evaluated. The system was designed to facilitate the delivery of the antibiotic, repurposed as an antitumoral agent. Moreover, the additive effect of the constituent CHAp ions was demonstrated and the triggered changes in the proteomic and lipidomic profiles were in detail described for the first time by SR-FTIRM. The analysis of TEM micrographs helped to elucidate the morphological variations in the cells treated with CHAp or DOX- CHAp nanoparticles, providing evidence that the mineral systems induce different death mechanisms in the normal and tumoral cell lines. In order to offer a more controlled drug release and to reduce the effect of CHAp components on the normal cells, the nanoparticles were included in electrospun PLA or PLA-PEG fibers in the following chapter. Interestingly, only the PLA-PEG scaffolds allowed the release of antibiotic.In the subsequent chapter, HAp was synthesized with an urchin-like morphology. These nanoparticles were characterized and their potential role as drug carrier of gentamicin was similarly described for the first time. In addition, urchin like nanoparticles with a fluor substitution were prepared and their encapsulation efficiency compared to the values obtained with CHAp and the non-substituted urchin-like systems. The formulated carriers were originally thought as an implant coating that could help prevent the post-surgical infections that remain the principal complication of the orthopedic procedures. The newly developed systems were successfully electrodeposited on the polydopamine/collagen coated implants, followed by a final electrodeposited layer of poly-lysine.
  
• MATOS RESINA, MARIA LEONOR: New multiresponsive materials platforms for cancer treatment: Smart electroconductive nanoparticles and transdermal devices
  
  Author: MATOS RESINA, MARIA LEONOR
  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 POLYMERS AND BIOPOLYMERS
  Department: Department of Chemical Engineering (EQ)
  Mode: Change of supervisor
  Deposit date: 07/10/2024
  Deposit END date: 18/10/2024
  Thesis director: ALEMAN LLANSO, CARLOS ENRIQUE | ALVES FERREIRA, FREDERICO CASTELO | ARAÚJO ESTEVES, TERESA SOFIA
  Committee:
       PRESIDENT: ESTRELA RODRIGUES CONDE, JOAO PEDRO
       SECRETARI: FERREIRA MORGADO, JORGE MANUEL
       VOCAL: VAZAO DE ALMEIDA, HENRIQUE MARTINIANO
       VOCAL: GELMI, MARIAL LUISA
       VOCAL: ACCARDO, ANTONELLA
  Thesis abstract: Cancer remains the leading cause of death in many developed countries. Despite significant progress in cancer treatment many challenges persist, such as severe side effects, damage to healthy tissues due to non-specific drug distribution and high systemic toxicity.Multiresponsive biomaterials systems have emerged as powerful tools for biomedical applications, especially in cancer treatment. This research aims to advance materials approaches to cancer therapy through the development of new electro-responsive materials platforms, incorporating smart nanoparticles (NPs) and transdermal or implantable devices. For example, NPs were used for controlled drug delivery triggered by electrical stimulation, while the devices also responded to secondary stimuli such as acidic pH or to the presence of tumor biomarkers. This combination of external and endogenous stimuli provides enhanced spatiotemporal control over drug delivery.Several therapeutic agents were tested, including an anticancer pentapeptide (CR(NMe)EKA), or drugs like curcumin, and chloramphenicol. The therapeutic agents were loaded into poly(3,4-ethylenedioxythiophene) NPs (PEDOT NPs), which provided the electrical stimuli response. These drug-loaded PEDOT NPs were then incorporated into various biomaterials scaffolds, such as pH-responsive hydrogels and bio-responsive fibers, creating multiresponsive devices. For instance, to achieve a multiresponsive injectable carrier for controlled delivery of the anticancer peptide CR(NMe)EKA, a biocompatible and pH-responsive hydrogel, formed by phenylboronic acid grafted with chitosan, was synthesized and loaded with PEDOT NPs. An electro-chemo responsive hydrogel for chloramphenicol release was prepared by grafting polyacrylic acid onto sodium alginate and encapsulating PEDOT NPs in situ. Additionally, a wireless biomaterials-based electrostimulation system was developed to enable controlled and on-demand release of anticancer drugs, promoting in vitro human prostate cancer cell death. This system utilized curcumin-loaded PEDOT NPs encapsulated in coaxial poly(glycerol sebacate)/poly(caprolactone) electrospun fibers.Overall, this work lays the foundation for designing and developing smarter, more effective biomaterial-based delivery systems for anticancer therapy.Keywords: cancer therapy; controlled drug delivery; electroresponsive nanoparticles; multiresponsive biomaterials; targeting cancer cells.
  

DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS

• HERNÁNDEZ PÉREZ, CARLOS: Implementation of personalized medicine in malignant melanoma patients aided by artificial intelligence
  
  Author: HERNÁNDEZ PÉREZ, CARLOS
  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: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: VILAPLANA BESLER, VERONICA
  Committee:
       PRESIDENT: JUAREZ HERRERO, JOSE MANUEL
       SECRETARI: CORTÉS MARTÍNEZ, JORDI
       VOCAL: CANCELA BARIZO, BRAIS
  Thesis abstract: Skin cancer, characterised by the uncontrolled growth of abnormal skin cells, poses a significant global health challenge. Melanoma, its most aggressive form, is particularly concerning due to its rapid metastasis if not detected early, leading to a sharp decline in survival probability. This underscores the critical importance of timely diagnosis and treatment. While advances have been made, the vast surface area of the skin makes early detection challenging.The emergence of prospective clinical and imaging databases has revolutionised the field, providing sensitive and specific biomarkers for non-invasive cancer diagnosis. This thesis harnesses these advancements, introducing AI-powered tools for melanoma analysis using clinical data and Whole Slide Imaging (WSI). The focus lies on identifying early-stage melanoma through risk grouping and biomarker detection. By employing advanced survival analysis, pattern recognition, and statistical clustering, the research develops predictive and interpretable models to enhance early detection and diagnosis.In our study, we comprehensively evaluate survival analysis algorithms on melanoma datasets, highlighting the superior performance of tree-based methods over deep learning models in this context. We also detail the development of SurvLIMEpy, an open-source Python library for model explainability in survival analysis, fostering trust between clinicians and AI. This library has garnered significant attention, with over 10,000 downloads.Furthermore, our research demonstrates that machine learning models prioritise clinically relevant features for survival predictions, further reinforcing their interpretability and clinical utility. We also showcase the successful application of machine learning for patient stratification, outperforming the AJCC staging system used by dermatologist and enabling more personalised treatment strategies. Additionally, the thesis explores AI-driven biomarker prediction from WSIs underscores this approach's promise while emphasising the need for larger datasets for clinical implementation.This research signifies an advancement in the application of AI for melanoma analysis. The SurvLIMEpy library has empowered the research community, while the findings on patient stratification and biomarker prediction potentially improve melanoma diagnosis and treatment.
  
• ROY, SWASTIKA: Beyond XAI for Trustworthy Federated Learning in 6G Zero-Touch Network Slicing
  
  Author: ROY, SWASTIKA
  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: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: VERIKOUKIS, CHRISTOS | CHERGUI, HATIM
  Committee:
       PRESIDENT: ALONSO ZARATE, LUIS GONZAGA
       SECRETARI: ADELANTADO FREIXER, FERRAN
       VOCAL NO PRESENCIAL: SPYROPOULOS, THRASYVOULOS
  Thesis abstract: In the approaching era of 6G networks, the necessity for AI-driven zero-touch network automation ishighlighted by the need to support multiple network slices for various use cases. Network slicing (NS),a significant innovation beyond 5G, will depend on AI to effectively manage complicated communicationnetworks. However, the traditional centralized approach for monitoring and controlling raw data facesseveral challenges. Federated Learning (FL) under a decentralized paradigm provides advantages,including improved security, fewer data exchanges, scalability, lower computational costs, and facilitatedfast local analysis and decision-making.Besides, Explainable AI (XAI) plays a crucial role in establishing trust in the AI black boxes throughoutthe deployment, which becomes imperative, mainly when AI is responsible for complicated resourcemanagement and anomaly detection. Stakeholders seek highly performing AI models for efficientresource allocation to ensure fairness, accountability, and compliance. Furthermore, flexible, intelligentmanagement across Radio Access Network (RAN), core network, cloud, and edge is needed to providerevolutionary connectivity in the broader context of the 6G era. The O-RAN Alliance’s push for Open RANarchitecture and AI-driven management tools further supports this vision.The thesis focuses on advancing the efficiency, scalability, transparency, and trustworthiness of 6Gnetworks through innovative approaches in FL, network resource management, and AI/MLmethodologies. The main objectives include reducing SLA violations, enhancing convergence time, andoptimizing computation costs in FL-based analytic engines. Additionally, the aim is to address the trade-off between performance and explainability, ensuring trustworthy predictions and transparent decision-making in the context of 6G network slicing. The proposed approaches leverage closed-loop automation,XAI, and novel federated learning models to achieve these goals while aligning with the demands andchallenges of the evolving 6G O-RAN landscape.First, A cloud-native SLA-driven FL model has been proposed to improve scalability and performance fornon-IID data at the RAN-Edge. It also demonstrated its superiority in reducing SLA violations andcomputation costs compared to different FL baselines.Second, inspired by closed-loop automation and XAI, we have designed an Explainable Federated DeepLearning (FDL) model to predict per-slice RAN dropped traffic probability, prioritizing explainabilitymetrics and outperforming baseline models.Third, we have proposed an explanation-guided in-hoc federated learning (FL) approach to address thetrade-off between AI performance and explainability for trustworthy 6G network slicing resourcemanagement in a RAN-Edge setup.Fourth, motivated by closed-loop (CL) automation and explanation-guided learning (EGL), we havepresented an explanation-guided federated learning (EGFL) scheme to ensure trustworthy predictionsand enhance model fairness.Lastly, addressing critical resource provisioning challenges among multiple virtualized base station (vBS)instances in the 6G O-RAN landscape, we have proposed a Federated Machine Reasoning (FLMR)framework to optimize CPU demand prediction for vBS, ensure transparent AI decisions and showcasesuperior performance compared to the DeepCog baseline.These methods advance 6G network scalability, efficiency, and transparency, contributing to developingAI-driven, trustworthy network management solutions.
  

DOCTORAL DEGREE IN SUPPLY CHAIN AND OPERATIONS MANAGEMENT

• ANICH GUTIÉRREZ, NICOLAS ENRIQUE: Metodología para el rediseño de cadenas de suministro multinegocio
  
  Author: ANICH GUTIÉRREZ, NICOLAS ENRIQUE
  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 SUPPLY CHAIN AND OPERATIONS MANAGEMENT
  Department: Department of Management (OE)
  Mode: Normal
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: MATEO DOLL, MANUEL
  Committee:
       PRESIDENT: DE CASTRO VILA, RODOLFO
       SECRETARI: CALLEJA SANZ, GEMA
       VOCAL: BENEDITO BENET, ERNEST
  Thesis abstract: Each supply chain arises in response to a new need, whether due to new customer groups or new forms of communicationwith customers. As reality evolves, new supply chains are designed, many of them similar to those existing. Currently, several supply chains of the same organization can be managed independently, either due to different customer groups or different marketing channels. This is a multi-business case. In turn, changes in the environment lead managers to modify the configuration of supply chains, which is a redesign. In addition, academic literature deals extensively with the design of supply chains, while redesign is limited; likewise, multi-business reconfiguration is not frequent.In this work, a methodology is developed for redesigning several supply chains corresponding to several businesses in a network structure called REDNURS (Re-Design Network Under Risk and Synergies). This methodology, based on asuccession of steps, determines the stages and levels of complementarity of a pivot chain with respect to others. The effects of synergies do not only include simple complementarities of activities, but also they take into account the different decision levels (strategic, tactical, and operational) and dimensions (static and dynamic) in supply chains.To this end, the MESHAV (Methodology of Evaluated Synergies Horizontally and Vertically) is developed. Its objective is, on the one hand, to achieve the measurement of synergistic sources and obtain a Horizontal Synergistic Factor. On the other hand, the dynamic behavior must be evaluated, which is achieved through a Vertical Synergistic Factor derived from the results obtained in its structural phase. All these structural and dynamic changes allow obtaining the Global Synergistic Factor of the network, the result of which is reflected in an a priori redesign of each multi-business chain.The use of qualitative and quantitative tools allows obtaining, from an a priori solution provided by MESHAV, a group of different types of architectures, which consider inventory levels, processing times, costs and service levels. To do this, algorithms are developed to optimize the redesign of this multi-business network. For which, static models are used for the structural dimension and dynamic models for the evolution of flows. The tools used are, first of all, simulation models in conjunction with AHP (Analytic Hierarchy Process) and TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) systems. The simulation allows analyzing the dynamic dimension; from a set of scenarios and configurations, dynamic indicators such as inventory times and levels are obtained. This result is used as the starting data for the resolution of the static dimension using linear programming models, either for the manufacturing stage or for the distribution stage.This work demonstrates the applicability of the research by developing the redesign of three supply chains in the pharmaceutical sector of a South American country and additionally the redesign for a global group that manufacturesautomobiles of different brands.
  

DOCTORAL DEGREE IN SUSTAINABILITY

• ESPINOZA AGUILAR, YURI PATRICIO: De la explotación extractiva a la recuperación ambiental, paisajes mineros su transición. Portovelo – Ecuador
  
  Author: ESPINOZA AGUILAR, YURI PATRICIO
  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 SUSTAINABILITY
  Department: University Research Institute for Sustainability Science and Technology (IS.UPC)
  Mode: Normal
  Deposit date: 30/09/2024
  Deposit END date: 11/10/2024
  Thesis director: MAYORGA CÁRDENAS, MIGUEL YURY
  Thesis abstract: In Ecuador, extractive exploitation constitutes one of the most relevant productive sectors due to its capacity to generate economic resources, at the same time mining has often caused severe environmental impacts, this qualification can be a consequence of both processes with little technological development, as well as the geographical characteristics and the environment in which the gold deposits are located. This study is based on the importance of the environmental, social and economic transformation that gold extraction has caused over time in Portovelo, a canton located in the south of Ecuador in the province of El Oro and considered the first mining center in the country.We live in a time in which humanity has given obvious importance to the protection of the environment, in the processes of extractive exploitation the environmental crisis is nothing more than one of the most perceptible symptoms due to the relationship between society and nature, in an unsustainable way. by the change in the natural heritage and culture. The increase in resilience in the face of transformations due to mining activities through the recovery, protection, defense and sustainable use of the mining heritage that is manifested in the landscape as an environmental and cultural indicator of the components, processes and combined characteristics. The recovery of mining landscapes is an element of affinity, identity and manifestation of the diversity that results from the articulation of the mining legacy of the place. However, other factors intervene and have intervened in its modeling, fragmentation and transformation. The infrastructure and equipment associated with the extractive activity, as well as the implantation of ways of life and work totally different from the traditional ones of the mining towns, have left a trace of a cultural nature that is totally perceptible by today's society. In this way, mining landscapes, better or worse preserved, have their own characteristics that vary from other landscapes and in turn have enough differentiating elements that distinguish them from each other.For this research, the phases of extractive exploitation and the socio-environmental consequences to heritage and its transition that have suffered over time as a consequence of population growth, changes in their customs and cultural identity are considered in an integrated manner, through specific methodologies. management with sustainability criteria that contribute to the environmental recovery of the landscape value of all its constituent elements applicable to the acquired legacy. It is important to evaluate in an articulated way the development, growth and planning of the mining heritage of Portovelo, aimed at identifying the aesthetic qualities, state and condition of the historical landscape that determines the constant interaction with the environment, the degree of alteration presented by environmental factors and social identified and its landscape valuation. The model will also be based on bibliographic work and field experimentation, embodied in transition sheets, thematic maps and geographic information systems, which corroborate what was found in the place of study.
  
• VIDAL MONÉS, BERTA: Unravelling the complexity of food loss and waste: towards sustainable food systems
  
  Author: VIDAL MONÉS, BERTA
  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 SUSTAINABILITY
  Department: University Research Institute for Sustainability Science and Technology (IS.UPC)
  Mode: Normal
  Deposit date: 27/09/2024
  Deposit END date: 10/10/2024
  Thesis director: DÍAZ RUIZ, RAQUEL | LOPEZ I GELAT, FELIU
  Thesis abstract: Global food systems pose both threats and solutions for sustaining quality of life in our planet. Roughly 40% of the food meant for humans is lost or wasted globally, exacerbating systems unsustainability. Urgent action is needed to reduce food loss and waste, yet progress towards SDG 12.3 is slow. We sustain that a crucial aspect of this challenge lies in an incomplete understanding of the problem, particularly at the extremes of the supply chain where significant amounts of food are lost and wasted. Primary production remains understudied while, consumption stages (households and food services) have been extensively analysed yet the issue persists. To foster effective action towards its prevention, the main goal of this thesis is to better characterize the causes lying behind the phenomenon. By doing so I address the three subdomains in need for further comprehension, each of them targeting one specific objective: 1) to characterize the complex nature of food loss at primary production; 2) to identify the dynamics prompting food waste generation in households under extreme event conditions, and 3) to evaluate the role of food waste prevention measures in food services.This thesis consists of three chapters utilizing diverse methodologies. Chapter 1 extensively examines the fruit and vegetable sector in Catalonia, enhancing understanding of food loss complexity through literature review, semi-structured interviews and participant observation. Identified causes were then reviewed and organized using complex-solving methods to recognize root causes. In Chapter 2, an online survey during the COVID-19 lockdown in Spain explores household food waste related behaviours. Chapter 3 proposes a methodological framework for co-designing food waste prevention strategies with canteen staff, measuring food waste at four school canteens in Barcelona. This involves direct measurement and participant observation to inform effective prevention actions based on nudging.This thesis provides evidence-based contributions for action towards food loss and waste prevention. Chapter 1 proved the multifaceted character of food loss, by describing 9 dimensions of causes, revealing and characterising their interconnectedness. In Chapter 2 dynamics related to food waste during the COVID-19 lockdown in households were identified, emphasising the importance of considering personal time and mental health when designing effective prevention measures. Finally, chapter 3 provided evidence on the effectiveness of nudging strategies in preventing food waste in school canteens, especially when co-designed and implemented with canteen staff. These findings are valuable for researchers, policy makers and stakeholders seeking to foster action towards food loss and waste prevention.
  

DOCTORAL DEGREE IN URBANISM

• BARRIOS AVALOS, JUAN JOSE: Reestructuración urbana de la Región Hidrológica 36 Nazas - Aguanaval, México: Modelos agroproductivos y sus sistemas hidrográficos
  
  Author: BARRIOS AVALOS, JUAN JOSE
  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 URBANISM
  Department: Department of Urbanism, Territory and Landscape (DUTP)
  Mode: Normal
  Deposit date: 30/09/2024
  Deposit END date: 11/10/2024
  Thesis director: FRANQUESA SANCHEZ, JORDI
  Committee:
       PRESIDENT: LLOP TORNE, CARLOS JUAN
       SECRETARI: MENDOZA ARROYO, MARIA DEL CARMEN
       VOCAL: SAINZ GUTIERREZ, VICTORIANO
  Thesis abstract: Hydrological Region 36 (RH36) is one of the 37 hydrological regions identified in Mexico by the National Water Commission. Within this region lie the basins of the Nazas and Aguanaval rivers, two endorheic rivers in northwestern Mexico. The waters of these rivers have enabled the Metropolitan Area of La Laguna to become a prosperous region with a significant agro-industrial sector. This success was achieved through the regulation of the rivers, primarily the Nazas River, via the construction of dams and canals between 1930 and 1990. However, the control established over the Nazas River through the Lázaro Cárdenas and Francisco Zarco dams, as well as the network of canals in the lower basin, exacerbated the loss of the Mayrán Lagoon at its mouth and led to the disappearance of flow in the lower basin in the area of Torreón, Gómez Palacio, and Lerdo.In the lower basins of RH36, there is significant water stress resulting from the overexploitation of major aquifers and the reduced availability of water resources due to the impacts of climate change. This research is based on the hypothesis that the severe water stress is partly caused by the disconnection between the regional infrastructure for water storage and distribution, agricultural irrigation systems, rural and urban populations, and their productive agricultural areas. Additionally, it is argued that hydraulic infrastructures have been planned without considering the regional urban context of the lower basin and its logical dimensions, leading to disruptions in the ecological matrix and the organization of rural populations.The research employs a basin approach to define the scope of the study. It sustained that for the restructuring of populations and the potential fluvial restoration of the Nazas and Aguanaval rivers, it is essential to understand the organization of all communities within the geographical boundaries. Each of the 33 sub-basins that make up RH36 are subject to an in-depth analysis of its urban and rural fabric. In addition to populations, the study of agricultural areas, hydraulic infrastructure, and road networks is a fundamental part of this basin approach.The thesis is organized into four chapters. The first chapter outlines the methodology, hypothesis, objectives, and the general structure of RH36. It also includes references to water storage structures in various contexts with geographical conditions similar to RH36. The second chapter is an atlas aimed at constructing morphological information about the 33 sub-basins of the region, including their urban, rural, and agricultural areas. This atlas is one of the main contributions of the research and serves as a prelude to Chapters III and IV. Chapter III explores global references on river restoration and dam removal, which serve as a foundation for Chapter IV, where the strategic approach to fluvial restoration in RH36 is presented.Finally, the research presents conclusions based on a thorough analysis of the urban and rural fabric, the hydrographic network, and hydraulic infrastructure. It argues that hydraulic infrastructures located in the urban-rural transition zones of intermediate cities within RH36 can provide ecosystem services and promote ecological and productive balance in the region. Furthermore, it maintains that the hydrological restoration in the lower courses of the Nazas and Aguanaval rivers is directly dependent on the restructuring of hydraulic infrastructure in both urban and rural populations throughout Hydrological Region 36.