DOCTORAL DEGREE IN COMPUTATIONAL AND APPLIED PHYSICS

• AKHTER, MOHAMMAD NAYEEM: Non-Hermitian mode management in optical fibers and waveguides
  
  Author: AKHTER, MOHAMMAD NAYEEM
  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: 29/11/2024
  Reading date: 20/01/2025
  Reading time: 11:00
  Reading place: Sala de Conferencies de l'edifici TR5, C/ Colom 9, Campus de Terrassa - UPC / https://meet.google.com/xyg-wpcb-xsf
  Thesis director: STALIUNAS, KESTUTIS | BOTEY CUMELLA, MURIEL
  Committee:
       PRESIDENT: MUSSOT, ARNAUD
       SECRETARI: PONS RIVERO, ANTONIO JAVIER
       VOCAL: TASOLAMPROU, ANNA
  Thesis abstract: This thesis uncovers a novel approach to tailoring optical beam transformations in GRaded INdex (GRIN) MultiMode Fibers (MMFs) through non-Hermitian mode management. Recently, MMFs have gained a resurgence of interest due to their demand in optical communications, high-power lasers, and dynamic fields of optical sensing and imaging. MMFs exhibit rich and complex spatiotemporal phenomena, and one of their main drawbacks is the poor quality of the propagated beam. Any beam injected in such fibers spontaneously evolves towards a multimode configuration generating speckle formation at the output. This randomness results from the different values of propagation constants of the fiber modes causing random mode phase shifts during propagation. This issue persists even in parabolic GRIN MMFs designed to have equidistant propagation constants, theoretically resulting in periodic self-imaging phenomenon. However, minor imperfections disrupt this mode equidistance, generally leading to randomness. Several approaches to tackling dephasing and randomization challenges include adaptive phase adjustment of the input beam and dissipative beam cleanup as the most common techniques. Recently, beam self-cleaning has been introduced as a novel approach to mitigate randomness effects, which relies on nonlinear mode coupling and, therefore, requires a high input beam power. Moreover, while self-cleaning redistributes energy among the modes, it maintains the integral properties of the beam, such as second-order moments in both real and wave number spaces, and the beam quality factor. Generally, conventional methods such as modulating the refractive index, dispersion, or nonlinearity along optical fibers, which may induce mode coupling, and parametric or Faraday modulational instability, do not efficiently reduce turbulence, since they generally broaden the angular spectra. This thesis presents a potentially transformative approach that enables an effective mode-cleaning while reducing turbulence. The proposal is based on the introduction of a periodic non-Hermitian modulation, by simultaneously engineering the refractive index and the gain/loss coefficient along the fibers or waveguides, allowing a precise control the mode coupling. Indeed, the field of non-Hermitian Photonics has recently become an ideal platform to uncover novel exotic physical phenomena such as breaking spatial symmetry and causality, with specific applications in dynamic periodic systems to improve laser performance or to condense optical turbulence, for instance. Thus, this thesis aims to control the mode coupling within MMFs and waveguides, using the concept of unidirectionality induced by periodic non-Hermitian potentials. Such unidirectional coupling among transverse modes, either towards lower-order modes or towards higher-order modes, is mainly governed by the spatial shift between the real and imaginary parts of the complex potential. This scheme leads to mode-cleaning in linear and active nonlinear fibers, as a main potential application. Moreover, we also explore the controlled generation of higher-order modes in parabolic GRIN MMF. Finally, we show it is also possible to tailor the beam profile in active non-Hermitian nonlinear GRIN MMFs. In addition, the proposed scheme leads to an effective all-optical mode-cleaning and thus reduces the second-order moments in both real and angular spaces. Importantly, these techniques no longer require high-power or manual adjustment of the input beam. We predict these effects analytically based on either a simplified Gaussian beam model or the standard mode expansion technique. The predictions are then numerically proven by solving the wave propagation equation introducing the longitudinal periodic non-Hermitian potential. The robustness and effectiveness of the proposed scheme have been discussed. We also estimate the conditions and parameters for the experimental realisation of predicted phenomena.
  
• HU, ZHEYAO: In silico design of inhibitors of RAS oncogenic proteins and strategies for blocking of tumour growth
  
  Author: HU, ZHEYAO
  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: 29/11/2024
  Reading date: 14/01/2025
  Reading time: 10:30
  Reading place: Sala de Conferencies de l'edifici TR5, C/ Colom 9, Campus de Terrassa - UPC
  Thesis director: MARTÍ RABASSA, JORDI
  Committee:
       PRESIDENT: ROVIRA VIRGILI, CARME
       SECRETARI: CANALES GABRIEL, MANEL
       VOCAL: CALERO BORRALLO, CARLOS
  Thesis abstract: In this Thesis we have performed all-atom molecular dynamics (MD) and well-tempered metadynamics (WTM) simulations of several benzothiadiazine (DBD)-membrane interaction systems, as well as of Rat Sarcoma (RAS) and RAS-Son of Sevenless (SOS1) solution systems. The first section is devoted to analyze the local structure of DBD and its derivatives embedded in bilayer membranes were analyzed. The most reactive sites of DBD are hydrogens ’H2’ and ’H4’ and oxygens, able to form hydrogen bonding (HB) interactions with the membrane components. The strongest HB interactions corresponded to the association between DBD’s ’H2’ and oxygens of DOPS in the absence of cholesterol. The cholesterol can weaken the DBD-lipid HB connections. Furthermore, the substituents of DBD have strong impact on the DBD-membrane interactions. The electron-donating substituents will enhance the HB interactions between DBD and phosphate groups of lipids, whereas electron-accepting groups will weaken the interactions with phosphate groups and enhance the interactions with ester groups of lipids. Later on, the impact of KRAS-G12 mutations was investigated. There are two new druggable dynamic water pockets located on KRAS-G12D-GDP-Mg2+ ternary complex. Subsequently, based on in silico drug design procedure the new potential KRAS-G12D inhibitor DBD15-21-22 was designed, which was proposed to locking KRAS-G12D in its GDP-bound "off" state. Furthermore, the free energy landscapes of the DBD15-21-22 and its derivatives in aqueous solution also been evaluated by WTM simulations. The proposed potential collective variables for the conformational dynamics investigation of small molecules can help to facilitate the in silico drug design by obtaining the corresponding 2D free energy landscapes. In the following section, the conformational characteristics of NRAS and their underlying atomic-level molecular interactions have been thoroughly analyzed by means of extensive MD simulations and trajectory analysis. The GTP-bound positively charged NRAS Q61 mutations (Q61R and Q61K) can be classified into one category, which have a small targetable pocket between α-helix 3 and switch-II. While the GTP-bound non-polar NRAS Q61L mutation fall into another class and the L61 can be captured by the hydrophobic pocket located on the α-helix 3. The new isomer-sourced structure iteration method was proposed to design the potential inhibitor (HM-387) for targeting the NRAS positively charged mutation. The HM-387 can tightly bind to GTP-bound NRAS-Q61R and gradually induce the protein conformation transition toward the "off-like" state. Moreover, the collective variables that can accurately characterize conformational changes in NRAS proteins were proposed, and then the accurate local structures of NRAS and its Q61 mutations in aqueous solution have been evaluated by WTM simulations. Finally, the SOS1-catalyzed GDP extraction process and the underlying atomic-level molecular interactions are described. The intrinsically disordered regions 807-818 (IDRs807-818) and αH domains of SOS1 cooperatively participate in the GDP extraction process: αH opens and inserts into the SW-I domain of wild-type KRAS, while the IDRs807-818 interact with the phosphate group of GDP. Among them, residues Lys811, Glu812, Lys939 and Glu942 play the main role. As for the KRAS-G12D mutation, the basic synergy of IDRs807-818 and αH is well-conserved during the GDP extraction steps and it is crucial for both wild-type and KRAS-G12D cases. However with the occurrence of G12D mutation, the molecular interactions of Asp12 with IDRs807-818, especially with residues Ser807, Trp809, Thr810 and Lys811 are enhanced, and increase the GDP extraction rate significantly.
  
• PUY CONTRERAS, ANDREU: Dynamic social patterns and information transfer in schooling fish
  
  Author: PUY CONTRERAS, ANDREU
  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: 26/11/2024
  Reading date: 21/01/2025
  Reading time: 11:00
  Reading place: Sala d'actes Manuel Martí Recobert, Edfici B6 - planta 0, C/ Jordi Girona 1-3 Barcelona, Campus Nord UPC.
  Thesis director: PASTOR SATORRAS, ROMUALDO
  Committee:
       PRESIDENT: ZAPPERI, STEFANO
       SECRETARI: ALONSO MUÑOZ, SERGIO
       VOCAL: REINA, ANDREAGIOVANNI
  Thesis abstract: Moving animal groups, such as flocks of birds, schools of fish, insect swarms, herds of mammals, and human crowds, exhibit intricate and highly coordinated behaviors. This thesis explores the underlying mechanisms of collective behavior by analyzing extensive, high-resolution experimental data of trajectories of schooling fish in a controlled environment.We first introduce a force map technique to investigate the alignment forces experienced by individual fish. After validating the method with an agent-based model, we apply it to experimental data and find evidence of effective alignment with faster neighbors, alongside an unexpected anti-alignment with slower ones. Instead of interpreting this as explicit anti-alignment behavior, we suggest it arises from a selective attention mechanism, where fish are less attentive to slower neighbors. This implies the existence of temporal leadership dynamics based on relative speeds, a hypothesis we support through both agent-based modeling and analysis of leader-follower relationships in the experimental data.Next, we examine how variations in perceived risk influence the behavior and interactions of fish within a group. By merging two subgroups of fish, each with different habituation levels to the experimental tank, we observe that individuals with higher perceived risk tend to occupy more central positions and show increased group cohesion, aligning with the selfish herd hypothesis. Beyond spatial positioning, we note behavioral adjustments in coordination, leader-follower dynamics, and burst-and-coast movement patterns. To further validate these findings, we develop a machine learning tool capable of identifying the subgroup identity of individual fish based on their behavior.We also investigate spontaneous behavioral cascades in schooling fish, focusing on turning avalanches, where large directional shifts are propagated through the group. Using tools from condensed matter physics and seismology, we analyze various avalanche metrics and reveal scale-free behaviour through power-law distributions, data collapses and scaling relationships. This confirms a necessary condition for criticality in fish schools. We also explore the biological role of turning avalanches, linking them to collective decision-making processes that govern changes in the school’s direction. Boundary effects from interactions with the tank walls, as well as the influential roles of boundary individuals, are also identified. Furthermore, by applying the nearest-neighbor declustering method from seismology, which is based on identifying main events and aftershocks, we uncover spatiotemporal correlations in avalanche events and an Omori-Utsu law with a faster decay rate compared to typical earthquake dynamics.Finally, we explore and extend the nearest-neighbor declustering technique for analyzing aftershock correlations in point processes. Using earthquake catalogs, we show that this method can in some cases produce spurious Omori-Utsu and productivity relationships in the absence of true correlations. However, by assessing the robustness of these results under variations in newly introduced parameters, we demonstrate that the method can reliably distinguish genuine aftershocks.Overall, this thesis provides novel insights into the mechanisms driving collective behavior in animal groups, emphasizing the role of selective social interactions and critical dynamics. Our empirical, data-driven approach highlights the complexity of animal collectives and lays a foundation for future studies on collective decision-making, leadership, and information transfer in biological systems.
  

DOCTORAL DEGREE IN ELECTRONIC ENGINEERING

• GON MEDAILLE, AXEL: Advanced characterization and modelling of innovative low-dimensional materials for solar cells applications
  
  Author: GON MEDAILLE, AXEL
  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: 05/11/2024
  Reading date: 20/12/2024
  Reading time: 11:00
  Reading place: Defensa pública en la Sala A2.14 del Edificio A del Campus Besós-EEBE
  Thesis director: SAUCEDO SILVA, EDGARDO ADEMAR | JEHL, ZACHARIE VICTOR SAMUEL NATHANAEL
  Committee:
       PRESIDENT: PÉREZ RODRÍGUEZ, ALEJANDRO
       SECRETARI: GARCÍA SÁNCHEZ SÁNCHEZ, MARIO FIDEL
       VOCAL: DIMITRIEVSKA, MIRJANA
  Thesis abstract: Energy transition keeps its course while new materials keep emerging promising better impact on environment. Among those materials, Q-1D chalco-halides materials using Bi and Sb, S, Se and I, Br, giving rise to wide combinations of materials. Most of them present the unique feature of a Pnma crystallographic structure allowing them to grow alongside one preferential direction, giving them optoelectronic properties highly seeked for PV applications, in particular for thin film solar cells. So far, Sb2Se3 has been the most investigated material within this class of material with an efficiency up until now of XX% in substrate configuration under AM1.5 spectrum illumination. Indeed, Sb2Se3 presenting the same crystallographic structure, is well-known within the PV community. However, despite having promising results over the past years, Sb2Se3-based solar cells reached a bottleneck in terms of efficiency. More generally, Q-1D chalco-halides materials either lack or do not have characterization data due to their recent emergence or re-emergence for some materials.This thesis will intend to address Sb2Se3 bottlenecks and present some solutions to allow Sb2Se3-based and other Q-1D chalco-halides solar cells to reach new heights through device modelling, present advanced characterization results from other Q-1D chalco-halides materials such as BiSeBr & SbSeI. Finally, the use of a novel material: Ti3C2Tx MXenes as selective contact suitable for those absorbers is also presented in this thesis. Firstly, a brief introduction of Sb2Se3 modelling parameters as well as BiSeBr & SbSeI results from by Raman spectroscopy and Time – Resolved Photoluminescence (TRPL) characterization are presented. A multi-wavelength investigation done by Raman spectroscopy coupled with novel Density Function Theory (DFT) are presented, giving information regarding the composition of the materials and the impact of the synthesis method for BiSeBr & SbSeI. Additionally, TRPL measurements highlighted the carriers’ dynamics and provide hints towards defects status of those materials. Altogether, this information helped to determine the potential of those new material as photo-absorber according to new figure of merit. Secondly, an emphasis is put on the device modelling using SCAPS-1D software and previous references to generate a qualitative model of Sb2Se3/CdS solar cells in substrate configuration to then design 2 numerical solutions to tackle the current bottlenecks experienced by the PV community. Those numerical solutions enable Sb2Se3 devices to reach 10.7% in efficiency by either implementing an ultrathin Al2O3 oxide intercalated between Sb2Se3 and CdS or operating a partial surface sulfurization on Sb2Se3 layer. Then, a simplified structure including only BiSeBr and 2 selective contacts was generated to pinpoint requirements from an electrical point of view. Although, due to software limitations, optical consideration is lacking to determine accurately suitable selective contacts, first approximations were determined through those simulations.Lastly, we develop the use of another novel material: MXenes Ti3C2Tx as a potential selective contact for Sb2Se3-based solar cells. Besides their wide range of deposition techniques and application, MXenes properties can be modulated alongside their synthesis. Initially, we perform materials characterization through Raman spectroscopy and X-Rays Diffraction (XRD) while changing intercalating agent and post deposition treatment (PDT) parameters to highlight this modulating feature. Then, we synthetized devices with Ti3C2Tx as hole transport layer (HTL) and Sb2Se3 as absorber. To improve carrier extraction, Se was incorporated on Ti3C2Tx layer under different PDT configurations. While PV performances were still poor compared to reference device without Ti3C2Tx some parameters presented some improvements upon Se incorporation onto Ti3C2Tx surface.
  
• JIMENEZ ARGUIJO, ALEX: Advanced strategies for the defect management in high efficiency kesterite solar cells
  
  Author: JIMENEZ ARGUIJO, ALEX
  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: 24/10/2024
  Reading date: 13/01/2025
  Reading time: 10:00
  Reading place: Defensa pública a la Sala Polivalent del Campus EEBE (Besós)
  Thesis director: SAUCEDO SILVA, EDGARDO ADEMAR | GIRALDO MUÑOZ, SERGIO
  Committee:
       PRESIDENT: GROSSBERG-KUUSK, MAARJA
       SECRETARI: CAZORLA SILVA, CLAUDIO
       VOCAL: CALVO BARRIO, LORENZO
  Thesis abstract: Kesterite-based solar cells represent a promising avenue towards sustainable energy production due to their reliance on abundant, low-toxicity materials, aligning with global initiatives to minimize environmental impact and enhance energy security. This thesis contributes significantly to the field by advancing the understanding and efficiency of kesterite solar cells through innovative defect management strategies and the development of high-performance devices.The research initially focuses on developing a comprehensive and realistic model of kesterite solar cells, which is pivotal in bridging the theoretical predictions with experimental results, providing a robust framework for the analysis of the efficiency limitations and identifying avenues for enhancement. By incorporating a realistic depiction on the influence of defects on the device performance, this model sets a new benchmark for the assessment and optimization of thin-film solar cells. The innovative approaches for defect control within kesterite materials are central to the thesis. The research demonstrates that through precise defect control by an induced electric field or transient doping with small atoms, such as hydrogen and lithium, it is possible to significantly modulate the defect structure of kesterite absorbers. These modifications lead to the decoupling majority carrier density from minority carrier lifetime, effectively enhancing the performance and efficiency of the solar cells. These approaches not only improve the electrical properties of the material but also provides a method to systematically address the intrinsic limitations of kesterite semiconductors.Moreover, the thesis presents advancements in the synthesis and processing of kesterite solar cells, employing techniques such as solution processing, doping, and interface passivation. These methods have been shown to considerably improve the compositional uniformity and optoelectronic properties of the materials, driving the efficiencies closer to those required for commercial viability. Notably, the development of solution-processed kesterite solar cells emerge as a scalable and environmentally benign method, indicating a significant step towards the industrialization of this photovoltaic technology.The thesis concludes that the strategies and methodologies developed herein substantially enhance the understanding and performance of kesterite solar cells. The findings underscore the potential of these materials in the transition to renewable energy sources, highlighting their role in promoting a sustainable future. With further refinement and optimization, kesterite solar cells could play a critical role in the global energy landscape, offering a viable, cost-effective, and environmentally sustainable solution to meet the growing energy demands.In summary, the work presented in this thesis exemplifies a significant advance in the field of photovoltaics, offering practical solutions and novel insights that pave the way for further research and development towards achieving high-efficiency, sustainable solar energy techniques.
  
• JIMENEZ GUERRA, MAYKEL: Innovative bulk and interfaces management on Q-1D Sb2Se3 based solar cells
  
  Author: JIMENEZ GUERRA, MAYKEL
  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: 31/10/2024
  Reading date: 24/01/2025
  Reading time: 10:00
  Reading place: Defensa pública a l'Aula A1.08, EEBE, campus Besós
  Thesis director: SAUCEDO SILVA, EDGARDO ADEMAR | SÁNCHEZ GONZÁLEZ, YUDANIA
  Committee:
       PRESIDENT: SPALATU, NICOLAE
       SECRETARI: PLACIDI, MARCEL JOSE
       VOCAL: GARCÍA SÁNCHEZ SÁNCHEZ, MARIO FIDEL
  Thesis abstract: This thesis investigated antimony Q-1D (Sb)-based solar cells as a promising alternative for sustainable energy generation, addressing critical challenges related to material properties, interfaces, and device architecture. Innovative strategies were developed to optimize optoelectronic properties and improve conversion efficiency, focusing on Sb2Se3, but including also preliminary studies on the Sb2(S,Se)3 solid solution, as well as exploring cadmium-free (Cd-free) materials as electron selective transport layers (ETL).A major achievement was the optimization of the Sb2Se3/CdS interface using chemical etching techniques, such as KCN treatment, which increased the average efficiency of solar cells from 4% to 5%, reaching 5.3% in the best-performing sub-cell. These treatments not only enhanced surface passivation but also altered surface polarity, resulting in the formation of a "buried junction" that improved the fill factor and overall energy conversion efficiency.High-pressure thermal annealings proved effective in enhancing crystal quality by increasing grain size, promoting preferred crystal orientations, and reducing defect density, which enabled a 5.8% efficiency using a new co-evaporation method. These findings demonstrate the feasibility of these techniques to improve device performance and reproducibility.Cadmium-free or significantly Cd-reduced configurations were explored to reduce environmental impact, achieving an efficiency of 6.6% in superstrate-configuration devices based on Sb2(S,Se)3, approaching the 7.6% benchmark achieved with CdS. In the substrate configuration, a Cd-free Sb2Se3 cell reached an efficiency of 5.2%, surpassing the 4.8% achieved with CdS, highlighting the potential of alternative materials to replace cadmium.Despite the progress made, several challenges remain, such as ensuring the stability of Sb2Se3 interfaces under operational conditions and optimizing new materials like SbSeI and SbSeBr. Improving the scalability of fabrication processes and the cost-effectiveness of new treatments are also key areas for future research. The results of this thesis provide a solid foundation for developing more efficient and sustainable Sb2Se3-based solar cells, emphasizing the importance of continued innovation in materials science and device engineering to overcome the remaining challenges and advance toward more scalable and efficient photovoltaic technologies.
  
• NIKSERESHT, SASAN: Self-Powered Integrated Circuits with Optical Communication
  
  Author: NIKSERESHT, SASAN
  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: 26/11/2024
  Reading date: pending
  Reading time: pending
  Reading place: pending
  Thesis director: COSP VILELLA, JORDI | FERNÁNDEZ MARTÍNEZ, DANIEL
  Committee:
       PRESIDENT: URANGA DEL MONTE, ARANTZAZU
       SECRETARI: MARTINEZ GARCIA, HERMINIO
       VOCAL: MICHALIK, PIOTR JOZEF
  Thesis abstract: The rapid development of Internet of Things (IoT) technologies is transforming data collection, analysis, and use across various industries, from industrial to biomedical applications. A specialized class of IoT, known as Smart Dust Motes (SDMs), has recently gained attention. These ultra-miniaturized, self-sustaining devices are capable of sensing, computation, and communication at a millimeter scale. However, despite their vast potential, SDM and IoT applications face significant challenges, particularly in power management, miniaturization, and communication efficiency.One of the primary challenges in distributing SDM technology is managing energy consumption. As the number of SDMs increases and they are deployed in remote environments, sustainable energy sources will be needed for autonomous operation over extended periods without maintenance. Traditional power solutions, such as batteries, are impractical for these systems due to size limitations and frequent maintenance requirements. Moreover, wireless communication, especially through Radio Frequency (RF), uses a significant amount of energy, which affects the requirements of these applications. As a result, current approaches, such as batteries and RF communication, often struggle to provide sustainable, long-term solutions for maintaining both power and communication efficiency.This dissertation proposes the design of a self-powered Application-Specific Integrated Circuit (ASIC) specifically developed for SDM and IoT applications, with the goal of addressing these challenges. The proposed system incorporates multiple key components, including a hybrid optical and RF transceiver and energy harvesting units. At the core of the system is the integration of negative photodiodes, which function both as light energy harvesters and optical data receivers, significantly minimizing the system's size and power consumption. The negative photodiodes provide higher efficiency than traditional positive photodiodes, improve energy conversion, and reduce both chip area and cost. The energy generated by the integrated photodiode is stored and regulated through an integrated voltage converter, which efficiently boosts the harvested energy to power the entire system. The hybrid communication system methods, offer flexibility for SDM applications where line-of-sight optical communication to be supplemented by RF transmission for enhanced range and reliability. A low-power reconfigurable RF transmitter, capable of operating in multiple modulation modes, enhance reliable communication even in non-line-of-sight conditions.To validate the proposed design, three prototype chips were fabricated using 0.18 µm CMOS technology and tested experimentally. The first prototype, featuring the hybrid optical/RF communication platform, achieved a data transmission rate of 20 kb/s with an optical receiver power consumption of 11 pJ/bit and RF transmission power of −18.65 dBm using light-harvested energy. The second optical receiver improved light data sensitivity using the DC-adapting comparison block technique. It consumed 60 nW of power and 1.5 pJ/bit at a transmission rate of 40 kb/s with a 0.5 V supply voltage. The energy-harvesting system demonstrated 57% efficiency and generated up to 8.7 µW of power from a negative photodiode area of 240 × 480 µm². These results demonstrate the system's capability to operate autonomously for extended periods, without the need for battery replacements or external power sources.
  

DOCTORAL DEGREE IN GEOTECHNICAL ENGINEERING

• ENCALADA LÓPEZ, DAVID ALEJANDRO: Soil Deterioration and Crack Formation during Drying. Mitigation Strategies
  
  Author: ENCALADA LÓPEZ, DAVID ALEJANDRO
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN GEOTECHNICAL ENGINEERING
  Department: Department of Civil and Environmental Engineering (DECA)
  Mode: Normal
  Deposit date: 29/11/2024
  Reading date: 20/01/2025
  Reading time: 11:00
  Reading place: ETSECCPB. UPC, Campus Nord Building C1. Classroom: 002 C/Jordi Girona, 1-3 08034 Barcelona
  Thesis director: LEDESMA VILLALBA, ALBERTO | PRAT CATALAN, PERE
  Committee:
       PRESIDENT: GALLIPOLI, DOMENICO
       SECRETARI: ROMERO MORALES, ENRIQUE EDGAR
       VOCAL: MENDES, JOAO
  Thesis abstract: This thesis investigates the cracking behaviour of deformable soils undergoing moisture exchange with the environment. The research combines experimental approaches, evaluates proposed models, and includes the evaluation of numerical modelling to understand the properties controlling soil cracking during desiccation.The experimental work encompasses four main areas: soil deformation measurement, suction measurement, soil-atmosphere interaction evaluation, and soil cracking assessment.Three methodologies were employed to assess soil deformation: direct measurement, volume displacement, and digital image analysis (DIA). DIA proved particularly effective, offering simplicity and rapidity in acquiring soil shrinkage curves (SSC) while providing additional information on soil colour changes due to water content variations. The collected data validated a proposed model capable of capturing various curve shapes, including J-shaped and S-shaped, with physically meaningful parameters.Suction measurements employed multiple techniques, including high-capacity tensiometers (HCTs), conventional tensiometers, water potential sensors, hygrometers, and filter paper. HCTs stood out for their extensive range and good overlap with methods estimating suction from relative humidity. These measurements facilitated the construction of soil water retention curves (SWRC) for different soil specimens.The volumetric and suction measurements at unconfined conditions, through SSC and SWRC, allowed the construction of part of the state surface (e-s-p). This data improves current constitutive models for unsaturated soils by considering the non-linear behaviour of suction-induced stiffness. An analytical solution for the e-s curve was derived from the proposed model, which aims to extend to confined conditions and link soil deformational behaviour with constrained swelling and swelling pressure.Soil-atmosphere interaction tests were conducted in an open atmosphere, environmental chamber, and large-scale field settings. These experiments evaluated soil evaporation stages and tested a model considering diffusion resistance and relative humidity at the soil surface. The impact of these factors varied with soil type: diffusion resistance significantly affected granular soils, relative humidity influenced high-plasticity clay, and low-plasticity soil was affected by both. A capillary barrier using a geosynthetic layer was evaluated as a mitigation strategy, demonstrating effectiveness in reducing evaporation and preventing cracking below the barrier.Soil cracking was assessed using two approaches: surface evaluation with DIA and X-ray computed tomography (CT) for depth analysis. Results showed good agreement with SSC, revealing that cracking represented a percentage of volume changes during induced shrinkage, depending on soil type and initial water content. X-ray CT revealed the influence of pre-existing flaws on crack formation and demonstrated incomplete crack sealing during wetting cycles.Fibre addition was tested as a crack reduction method, showing effectiveness in the first drying cycle but reduced efficacy in subsequent cycles. X-ray CT observations highlighted the persistence of sealed cracks as weak points, leading to crack reopening along previous paths.Finally, numerical modelling focused on simulating soil deformation in selected soil-atmosphere interaction tests. The models emphasised the importance of boundary conditions, particularly mass and heat transfer coefficients, in representing soil-atmosphere interaction. The simulations corroborated the capillary barrier effect of geosynthetics as an effective strategy for moisture preservation and crack prevention.
  

DOCTORAL DEGREE IN OPTICAL ENGINEERING

• PARRA MARTÍNEZ, ALBERT: Integrating AI with Multiphoton Autofluorescence-Based Hyperspectral Imaging for Enhanced Embryo and Oocyte Analysis
  
  Author: PARRA MARTÍNEZ, 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 OPTICAL ENGINEERING
  Department: Department of Optics and Optometry (OO)
  Mode: Normal
  Deposit date: 18/10/2024
  Reading date: 13/01/2025
  Reading time: 11:00
  Reading place: Defensa pública Auditori Joan Salvadó del Centre Universitari de la Visió
  Thesis director: OJOSNEGROS MARTOS, SAMUEL
  Committee:
       PRESIDENT: DUOCASTELLA SOLÀ, MARTÍ
       SECRETARI: TRULL SILVESTRE, JOSE FRANCISCO
       VOCAL: MARTIN BADOSA, ESTELA
  Thesis abstract: Infertility affects one in seven couples, according to the World Health Organization, and only around 30% of the embryos from in vitro fertilization treatments successfully implant in the uterus and develop to term. As a result, multiple transfer cycles are often required to achieve a successful pregnancy, which can lead to significant emotional, physical, and financial burden. To reduce time-to-pregnancy and stress for patients, there is a need for a diagnostic tool to better select embryos and oocytes based on their physiology.This thesis presents an innovative, non-invasive methodology to improve embryo and oocyte selection, moving beyond conventional brightfield imaging, which provides morphological information and therefore limited physiological insight. Using a combination of techniques including two-photon excitation, hyperspectral imaging, phasor analysis, and artificial intelligence, we have developed a novel imaging pipeline that enables the non-invasive study of metabolic profiles of embryos and oocytes through their intrinsic autofluorescence signals. This methodology not only offers a more comprehensive understanding of embryo viability, but also represents a significant advancement in the field of reproductive science, enabling non-invasive metabolic profiling in ways that were previously not possible.The proof-of-concept work conducted in this thesis led to the development of a prototype based on light-sheet microscopy for evaluating and classifying embryos. This technology was chosen because of its ability to provide faster, less invasive imaging, while avoiding photodamage, making it ideal for non-invasive analysis. This prototype represents the first step towards a clinical product to use in in vitro fertilization clinics. By offering a method to accurately assess embryo viability non-invasively, we aim to improve the effectiveness, and patient experience of infertility treatment.
  

DOCTORAL DEGREE IN PHOTONICS

• 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
  Reading date: 19/12/2024
  Reading time: 12:00
  Reading place: ICFO, Mediterranean Technology Park, Avinguda Carl Friedrich Gauss, 3, 08860 Castelldefels, Barcelona
  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.
  

DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS

• CARRASCO RIBELLES, LUCÍA AMALIA: Multimorbidity and frailty trajectories and explainable prediction models for health-related outcomes using longitudinal electronic health records of the ageing Catalan population
  
  Author: CARRASCO RIBELLES, LUCÍA AMALIA
  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: 07/11/2024
  Reading date: 20/12/2024
  Reading time: 10:30
  Reading place: Aula Teleensenyament, Edifici B3, ETSETB, Campus Nord, Barcelona
  Thesis director: CABRERA BEAN, MARGARITA ASUNCION | VIOLÁN FORS, CONCEPCIÓN
  Committee:
       PRESIDENT: GARCÍA GÓMEZ, JUAN MIGUEL
       SECRETARI: HERNANDO PERICAS, FRANCISCO JAVIER
       VOCAL: CATALÀ SABATÉ, MARTÍ
  Thesis abstract: As life expectancy rises, people over 65 years old become a larger proportion of the population. However, longer life expectancy does not imply healthy ageing. Older individuals are more likely to develop multiple chronic diseases and other disabling conditions such as frailty. These conditions not only reduce quality of life but also place significant demands on an already strained healthcare system. This thesis aimed to 1) enhance understanding of the relationship and progression of frailty and multimorbidity, 2) study how frailty modifies multimorbidity patterns and trajectories, and 3) develop explainable predictive models using longitudinal electronic health records (EHRs). All the studies focused on three outcomes: all-cause mortality, nursing home admission, and home care need. Utilising SIDIAP, the primary care EHR database in Catalonia, enabled the development of large, population-based longitudinal studies with greater generalisability and the application of more sophisticated analytical techniques. This thesis yielded several important findings and recommendations. Firstly, it was demonstrated how the characterisation of multimorbidity and frailty and their impact on health-related outcomes evolves with age. The accumulation of diseases increases the likelihood of death, but older individuals with fewer diseases and more frailty-related deficits are more likely to require specialised care. Therefore, treatment plans should be tailored based not only on age but also on the specific characterisation of the patient at any given time. Secondly, the study found that multimorbidity patterns and trajectories are modified when frailty is considered, improving their predictive power for some health-related outcomes. Thus, future research on multimorbidity in older populations should integrate frailty information. Thirdly, a predictive model that addressed the technical challenges of longitudinal EHRs and incorporated mechanisms to enhance transparency was developed and called ARIADNEhr. During ARIADNEhr's development, it was found that increased model complexity does not necessarily improve discriminability but does enhance the clinical plausibility of the resulting attention maps. This model generally outperformed others using cross-sectional data. Additionally, the model's performance was validated with an external population, specifically in the UK with the CPRD database. This thesis exemplifies the transfer of advanced analytical techniques, such as clustering and deep learning, to the health field, supported by rigorous validation to ensure reliability. It offers valuable insights for future studies on the ageing population, emphasising the need for having access to longitudinal, high-quality data such as that from primary care. The findings aim to improve treatment penalisation, enhance patients' quality of life, and reduce costs for the national healthcare system.
  

DOCTORAL DEGREE IN SUSTAINABILITY

• AGUDELO VALDERRAMA, VANESSA: Integración de la relación salud humana y cambio climático en el marco de la resiliencia urbana. Propuesta metodológica de evaluación y operacionalización en un contexto Latinoamericano
  
  Author: AGUDELO VALDERRAMA, VANESSA
  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: 22/11/2024
  Reading date: pending
  Reading time: pending
  Reading place: pending
  Thesis director: MORATO FARRERAS, JORDI
  Committee:
       PRESIDENT: CORREIA GUEDES, MANUEL
       SECRETARI: ALVAREZ DEL CASTILLO, JAVIER
       VOCAL: MENA NIETO, ÁNGEL ISIDRO
  Thesis abstract: This study addresses the relationship between climate change and human health in the framework of urban resilience in a Latin American context. It sought to strengthen the climate and health components through conceptual harmonization and integration, as well as the identification of indicators within urban resilience measurement models. Thus, the first proposal of a model for measuring the urban resilience index adapted to Latin American cities is presented, specifically addressing the relationship between climate change and health. This model was validated and operationalized through a case study in two vulnerable communities in urban-rural transition areas in Santiago de Cali, Colombia.The approach included estimating five indicators of health, natural disasters, climate variability, socio-economic, governance, and satisfaction, where resilience negatively correlates with vulnerability. Given the limited monitoring and systematization of information in Latin American cities, much of the data was collected through structured interviews. The results revealed patterns characteristic of highly vulnerable Latino communities, such as a high degree of self-management to solve problems and improve quality of life. These findings provide elements to infer and prioritize communities with a strong sense of ownership, enabling the effective implementation of climate change adaptation and mitigation measures, given the high likelihood of ownership and continuity.
  

DOCTORAL DEGREE IN THEORY AND HISTORY OF ARCHITECTURE

• GRATACÒS BATLLE, RICARD: La Carta de l'hàbitat. Aproximacions etnogràfiques i instruments d’estudi de l’espai habitat en el marc del novè CIAM d'Aix-en-Provence (1953)
  
  Author: GRATACÒS BATLLE, RICARD
  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 THEORY AND HISTORY OF ARCHITECTURE
  Department: Department of History and Theory of Architecture and Communication Techniques (THATC)
  Mode: Normal
  Deposit date: 21/11/2024
  Reading date: 08/01/2025
  Reading time: 11:00
  Reading place: Presencial (ETSAB. Sala de Graus)
  Thesis director: LLORENTE DIAZ, MARTA
  Committee:
       PRESIDENT: TORRES CUECO, JORGE
       SECRETARI: BITRIÁN VAREA, CARLOS
       VOCAL: ARDEVOL PIERA, ELISENDA
  Thesis abstract: The doctoral thesis revolves around the ninth CIAM (Congrès Internationaux d'Architecture Moderne) held in Aix-en-Provence in 1953. It focuses on the work presented by some European architects who were working in cultural contexts foreign to their own. Faced with the need to understand the “cultural other,” they incorporated into their work elements of ethnographic fieldwork. The main hypothesis of the research is that there is an ethnographic turn in the work of these modern architects, stemming from the necessity to approach the vital needs of a society different from their own.The CIAM IX took place in Provence to celebrate the opening of the Unité d'Habitation in Marseille the previous year, and on its rooftop, the 25-year history of CIAM was commemorated. The chosen debate topic was human habitat, with the primary goal of the gathering being the drafting of a Habitat Charter to complement the Athens Charter. The aim was to end the meeting with a solemn declaration proclaiming the right to housing for all human beings. The thesis explores the precise moment when the idea of working on a Habitat Charter was born. It reconstructs the “grids” presented by the CIAM groups from Algiers and Morocco, delving into the analytical study tools they used to understand the built realities of the Maghreb. In the context of profound transformations in international geopolitics following World War II, some architects and urban planners working in Morocco and Algeria were sensitive to the social and cultural realities with which they worked, developing studies, policies, and housing projects for Muslim populations. These architects adhered to the tenets of the functional city but adapted them to the specificities of the context in which they worked. They anticipated the industrialized future that Morocco and Algeria would achieve, participating in an economy of international exchange and acknowledging that they were working with a society in full transformation. For this reason, they aimed to develop a habitat capable of integrating into this changing society. We owe these architects the attention directed toward cities made of barrels and other industrial waste, as well as their insight that these constructed forms held lessons for modern architecture and the city.The doctoral thesis also addresses contributions presented at the congress focusing on the study of inhabited spaces in non-industrialized societies. The study and debate on the inhabited space of “primitive peoples” were represented by a group of young architecture students from the École des Beaux-Arts in Paris, who presented extensive documentation compiled after a long stay in Cameroon. In this context, some architects at the congress praised the lessons of architecture produced by “primitive societies,” which, without our industrialized technical skills, were able to shape their habitats through a singular worldview, a culture so balanced and just in meeting its needs that it appeared beautiful to the eyes of modern architects.The CIAM in Aix-en-Provence ended without successfully drafting the Habitat Charter. What remains from that time is a spirit and an energy from an era when architects and urban planners aspired to address the housing problem on a large scale. They were idealists who saw the need to collaborate with diverse disciplines, experimenting with ethnographic methods without formal training and approaching sociology to restore dignity to human habitats.
  
• HEINONEN, PIJATTA MAARIA: Beyond planning: Prefiguring horizontal practices of architecture in the context of autonomous geographies
  
  Author: HEINONEN, PIJATTA MAARIA
  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 THEORY AND HISTORY OF ARCHITECTURE
  Department: Department of History and Theory of Architecture and Communication Techniques (THATC)
  Mode: Normal
  Deposit date: 25/09/2024
  Reading date: 20/12/2024
  Reading time: 12:00
  Reading place: Face-to-face (Room Sala de Graus. ETSAB. Main floor)
  Thesis director: MONTANER MARTORELL, JOSE MARIA | HERNÁNDEZ FALAGÁN, DAVID
  Committee:
       PRESIDENT: OYON BAÑALES, JOSE LUIS
       SECRETARI: FERRERI, MARA
       VOCAL: GARCÍA VÁZQUEZ, CARLOS
  Thesis abstract: Hegemonic organization of space and architecture as its essential means respond to political and economic intentions whose determination is out of most people’s reach. Representations of dominant practices are embedded in the order and form of space, reaching the spaces and practices of everyday life. The reform of architecture alone has been understood as insufficient in addressing the imbalance of power, indicating the necessity of more fundamental changes in the societal context that architecture depends on. The possible politics of space that would be based on decentralization and inhabitants’ self-determination have been approached theoretically. However, investigations into architectural practices that are, in fact, taking place in counter-hegemonic contexts are few. This study investigated architecture that emerges within the prefiguration of social change, focusing on social movements whose autonomous politics are characterized by horizontal, egalitarian, and non-capitalist principles. The research questions were: What are the characteristics of architectural decision-making, and, what are the characteristics of the architecture carried out in occupied, largely self-built autonomous geographies? The research was based on grounded theory and was guided by simultaneous collection and analysis of data as well as theoretical sampling. Data was collected in three different autonomous geographies in Central Europe. The methods of data collection were participant observation, drawing, mapping, and interviews. The analysis was based on qualitative coding and followed the constant comparative method. The study found first that, in the examined geographies, the collective organization of space is carried out in a direct democratic, transparent manner. Collective decision-making highlights the direct participation of everyone in relevant decisions, from the founding principles of organization to the specific patterns and forms of space. Second, the collective organization of space is voluntary and partial. It is combined with decentralization of decision-making and individual autonomy of intervening in space. Autonomy facilitates a certain freedom to transform space and the social relations implied within, beyond their collective determination. In the examined geographies, spatial organization develops through simultaneous collective and autonomous interventions in a partially non-planned manner. Third, the inhabitants question the property of space and the permanence of architectural form. The open, common, and malleable nature of space enables its transformation according to horizontal lines, referring directly to the inhabitants present. The findings provide new insights into an architecture based on the politics of participation. While the study supports previous theorizations, one of its main contributions is the elaboration of architectural participation as it relates to the shifting negotiation between the individual and the collective. Furthermore, the principal theoretical implication of this study is the questioning and negation of overarching planning that the findings suggest. Instead of exhaustive instruments such as the urban plan, the findings indicate a less invasive idea of coordination-in-space that arises voluntarily from the bottom up. Finally, while questioning certain precepts of normative planning, the study also indicates directions to explore further the possibilities of an indeterminate, horizontal organization of space.
  

DOCTORAL DEGREE IN AGRI-FOOD TECHNOLOGY AND BIOTECHNOLOGY

• FULLANA PONS, AÏDA MAGDALENA: Management strategies of Meloidogyne-resistant plant germplasm to avoid virulence selection
  
  Author: FULLANA PONS, AÏDA MAGDALENA
  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 AGRI-FOOD TECHNOLOGY AND BIOTECHNOLOGY
  Department: Department of Agri-Food Engineering and Biotechnology (DEAB)
  Mode: Normal
  Deposit date: 16/12/2024
  Deposit END date: 09/01/2025
  Thesis director: SORRIBAS ROYO, FRANCISCO JAVIER | GINÉ BLASCO, ARIADNA
  Committee:
       PRESIDENT: CASTILLO CASTILLO, PABLO
       SECRETARI: SERRANO PORTA, LIDIA
       VOCAL: HELDER, JOHANNES
       VOCAL: MORTON JUANEDA, ANA
       VOCAL: PISA MATA DA CONCEIÇÃO, ISABEL LUCI
  Thesis abstract: During the development of the PhD, several studies were conducted to explore the potential of plant resistance for the management of Meloidogyne in horticultural crops, none of which promoted the selection of virulent populations in the resistant germplasms used. Specifically: i) the effect of three growing seasons of resistant germplasm rotation; ii) the effect of Solanum torvum as a tomato rootstock as a method of alternating resistance sources in monoculture situations; iii) the capacity of zoophytophagous mirids to induce resistance in tomato germplasm susceptible to nematodes to reduce the frequency of use of resistant germplasm.; and iv) the response of potential rootstocks of melon and cucumber or watermelon to quarantine species in Spain as a possible management tool if they are found and not eradicated. The results obtained showed that: i) the rotation sequence with resistant germplasm ( tomato grafted (grft.) onto ‘Brigeor’ - melon grft. onto Cucumis metuliferus - pepper grft. Onto ‘Oscos’ – watermelon grft. onto Citrullus amarus - resistant tomato cv. Caramba) cultivated in plots infested by an avirulent (Avi) or partially virulent (Vi) population of M. incognita to the Mi1.2 resistance tomato gene reduced the Avi population density by 94% and the Vi population density to below detectable levels. Cumulative yield was 1.5 and 2.4 times higher in plots infested with Avi and Vi, respectively, compared to rotation with susceptible germplasm. The Avi population did not acquire virulence to any of the resistant germplasms used in the rotation; ii) the severity of the disease and nematode reproduction in tomatoes grafted onto S. torvum were reduced by 8.6 and 56 times, respectively, compared to non-grafted tomatoes, and yield was up to 87% higher at densities above 1 J2/cm3 of soil. The resistance of S. torvum remained unchanged after three consecutive crops; iii) exposure of susceptible tomatoes to 15 nymphs/plant of Nesiodiocoris tenuis or Macrolophus pygmaeus for 24 hours before transplanting such as (Z)-3-hexenil propanoato volatile emitted by fed tomato plants, reduce nematode’s reproduction until 60, 70 and 45% respectively; and iv) Cucumis metuliferus was immune to M. chitwoodi, highly resistant to M. enterolobii, and resistant to M. luci. Citrullus amarus ranged from resistant to moderately resistant to M. chitwoodi and M. enterolobii, and resistant to M. luci.The results of these studies provide valuable information for nematode control, even in scenarios where species and/or populations virulent to specific resistance genes coexist, which are increasingly common in production areas.
  

DOCTORAL DEGREE IN ARCHITECTURAL, BUILDING CONSTRUCTION AND URBANISM TECHNOLOGY

• ORTEGA CASTILLO, IVÁN: Protocol d'anàlisi del sòl urbà consolidat en l'àmbit de la regeneració urbana: el cas de Ca n'Anglada - Terrassa (Barcelona)
  
  Author: ORTEGA CASTILLO, IVÁN
  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 ARCHITECTURAL, BUILDING CONSTRUCTION AND URBANISM TECHNOLOGY
  Department: Department of Architectural Technology (TA)
  Mode: Normal
  Deposit date: 05/12/2024
  Deposit END date: 19/12/2024
  Thesis director: LACASTA PALACIO, ANA MARIA | GIRALDO FORERO, MARIA DEL PILAR
  Thesis abstract: The main purpose of this thesis is to develop an analysis protocol for consolidated urban areas using territorial indicators as the main part of the methodology. It examines contemporary urban architecture through numerical factors that relate to the transversal themes of the territories, in order to facilitate proposals for interventions in urban regeneration.Since the mid-20th century, urban settlements have experienced significant demographic growth due to increased migratory movements from rural areas to cities. This has led to territorial expansion, causing many areas to develop rapidly without specific urban planning regulations, resulting in serious structural deficiencies. One of these areas is the neighborhood of Ca n'Anglada, located in the municipality of Terrassa. It is a representative example of a consolidated urban area with strong interdisciplinary issues, and has been the subject of various public administration interventions without success. To understand the current issues, a preliminary analysis is presented that addresses interdisciplinary factors through the sociological, territorial and urban perspectives, tracing the development of the area from its origins to the present day, marked by a society and a territory that are strongly divided.Currently, urban regeneration operations in consolidated urban lands involve a great previous analysis work, which in many cases implies a great search for data that is found in various sources, which makes it difficult to get an idea of the globality of the problems of the territories. For this reason, subsequently through a systematic review of existing bibliographic references and their evaluation based on the content and background of each document, the main territorial indicators in urban planning are selected to analyze the neighborhood of Ca n'Anglada from a completely objective point of view. The bibliographic references deemed valid for developing the protocol also help define a set of optimal values and result ranges for each territorial indicator, determining the most favorable values for the territories in the analyzed aspects and categories. The study proposes processing this large volume of data from various sources to calculate each of the indicators using a database system with a structured language. This approach enables more efficient and straightforward management of the numerical values and allows for the subsequent representation of the results using geolocation software.This protocol is presented with clearly differentiated phases according to their temporal space, from an objective point of view. The first phase analyzes the current state of the neighborhood, presenting aspects reflected by the territorial indicators. The second phase assesses the results of the territorial indicators selected in the study of major urban planning operations in urban regeneration that have been carried out so far and may have significantly impacted the area. The final phase presents proposals for urban regeneration, considering both the pre-existing conditions and the current state. By applying the defined protocol, we obtain a precise image of the area’s problems and its opportunities for action to address themThus, with the development of this protocol for the analysis of consolidated urban areas, using the Ca n’Anglada neighborhood as an example, a set of analysis methodologies is created to automate current processes and enable greater agility in the workflows of technical drafters of urban planning modifications. This protocol facilities the phases of situational analysis and the development of urban planning, as well as monitoring the evolution of the actions.
  

DOCTORAL DEGREE IN AUTOMATIC CONTROL, ROBOTICS AND VISION

• CALDARELLI, EDOARDO: Learning control from data: Convergence guarantees and applications to robotic cloth manipulation
  
  Author: CALDARELLI, EDOARDO
  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: 05/12/2024
  Deposit END date: 19/12/2024
  Thesis director: TORRAS GENIS, CARMEN | COLOMÉ FIGUERAS, ADRIÀ
  Thesis abstract: Robotics has been recently challenged by new tasks, such as the manipulation of deformable objects like cloth, arising from theuse of robots outside standard industrial scenarios. These manipulation skills have the goal to assist humans in their dailyactivities, with the ultimate objective of improving their living standards, especially in the case of elderly or physically impairedpeople.In such a context, programming the behavior of a robot may need to be done by non-robotics experts, and take into considerationadditional parameters besides the plain trajectories to be followed, such as the stiffness, or impedance, of the roboticmanipulator. In this sense, classic control policies can be combined with machine learning algorithms, achieving a data-drivencontrol pipeline. The desired robot’s behavior can be inductively inferred from a suitable dataset, without requiring low-levelprogramming of the robot’s motions. Specifically, the task skills can be learned: in a prescriptive way, by directly recording theirexecution by a human expert (the so-called learning from demonstration); in a model-based fashion, by constructing a surrogatemodel of the robot’s surroundings, and letting the robot decide how to act based on it (in a model predictive control fashion).This thesis proposes advances in the field of data-driven control for robotic manipulation, tackled from both the learning fromdemonstration, and the model-based perspective. Most of the learning modules involved in the thesis rely on kernel methods.While being computationally costly, kernel methods enjoy strong optimality guarantees, and allow for fast, provably accurateapproximations to be deployed.In this thesis, we first study how to learn time-dependent stiffness profiles from human demonstrations, and design a novel, activelearning algorithm to achieve this goal. Besides this contribution, we investigate how the human demonstrations of a given taskcan be processed efficiently, by means of an approximated, kernel-based motion primitive. On the other hand, considering themodel-based scenario, we first propose the usage of efficient predictive control techniques for cloth manipulation. Moreover, wedevelop an approximated, kernel-based regression algorithm for learning and controlling nonlinear dynamics, within the context ofthe so-called Koopman operator regression. Besides these algorithmic contributions, we further put a focus on the theoreticalproperties of the kernel approximations considered, bridging techniques from the statistical learning and the control theory fields.In particular, we prove new rates of convergence both for our efficient motion primitive representation, and for the dynamics modelretrieved in Koopman operator regression.
  
• LOPES E SILVA, BRUNO MIGUEL: Artificial Intelligence to Improve Plastic Molding Processes
  
  Author: LOPES E SILVA, BRUNO MIGUEL
  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: 17/12/2024
  Deposit END date: 10/01/2025
  Thesis director: ALENYÀ RIBAS, GUILLEM | CHARRUA DE SOUSA, JOÃO MIGUEL
  Thesis abstract: This thesis advances the field of production processes, specifically injection molding, toward the goal of Zero Defect Manufacturing (ZDM), with an emphasis on improving quality prediction methods through Artificial Intelligence (AI). It explores innovative strategies for improving the efficiency and quality of manufacturing processes, highlighting the importance of minimizing defects in industrial production.The research begins with an analysis of the current state of predictive quality systems in injection molding processes, identifying the critical need for advances to achieve ZDM. By collecting data from legacy and modern equipment, this work establishes a basis for a comprehensive analysis, using standard protocols and new methodologies for data collection. Central to this thesis is the application of feature selection algorithms, which employ a combination of filter, wrapper, embedded, and hybrid approaches. This framework is designed to accurately identify the key parameters that influence the quality of the injection molding process, thereby facilitating more effective and predictive modeling of manufacturing results. In addressing quality prediction, the thesis introduces both supervised and unsupervised models to predict manufacturing quality. It particularly focuses on enhancing these models with human knowledge, integrating expert insights into the predictive algorithms to better adapt to the complex dynamics of the manufacturing environment. This approach not only improves the accuracy of predictions but also enriches the models with practical, real-world applicability. Through a series of detailed use cases, the effectiveness of the proposed methodologies is demonstrated across various equipment and manufacturing scenarios. The results highlight significant improvements in process predictability, contributing to the reduction of defects and moving closer to the ideal of ZDM. The conclusion of this thesis reiterates the importance of its contributions to the field of AI used in production processes, with a focus on injection molding, providing a solid foundation for future research aimed at improving the integration of data-driven and human-centered approaches in manufacturing. The thesis outlines potential pathways for continued innovation in digitalization, feature selection, and quality prediction, emphasizing the ongoing pursuit of excellence in manufacturing processes.
  
• ROMERO BEN, LUIS: CONTRIBUTIONS TO THE REAL-TIME LEAK MANAGEMENT OF WATER SYSTEMS
  
  Author: ROMERO BEN, LUIS
  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: 10/12/2024
  Deposit END date: 23/12/2024
  Thesis director: PUIG CAYUELA, VICENÇ | CEMBRANO GENNARI, M.GABRIELA ELENA
  Thesis abstract: This thesis presents several contributions to the state of the art of real-time monitoring of water distribution networks. Specifically, this thesis analyses the leak management problem, one of the major challenges within the field of monitoring of water distribution networks. Its importance lies in the high costs associated to the water losses. The thesis proposes contributions to address two fundamental problems: the localization of leaks and the strategic placement of sensors to improve leak localization. These contributions are mainly focused on data-driven methodologies, characterized by their independence from hydraulic models, which can be hard to generate and calibrate for water utilities. About leak localization, an initial two-stage data-driven approach is proposed. First, a quadratic programming problem estimates the complete hydraulic network state, given by the hydraulic head (pressure + elevation) at the nodes. This process, denoted as Graph-based State Interpolation (GSI), only uses data from pressure sensors and the structure of the network. Then, a technique called Leak Candidate Selection Method (LCSM) compares leak and leak-free estimated states to indicate the leak location. The complete estimation-localization method is called GSI-LCSM. Throughout the thesis, several improvements are proposed for this method.Firstly, learning schemes are applied or combined with GSI-LCSM to improve node-level localization accuracy. Three different learning-based methods are presented, namely GSI-DL, which uses Dictionary Learning (DL) to learn from estimated residuals; LL-GSI-LCSM, which adds an adaptive learning layer to GSI, improving the localization during its online application; and DeepFGSI, which derives a simplified version of GSI, used to add network information to the layers of a deep learning scheme. Then, the interpolation of GSI is improved by considering the physics behind the dynamics of a water network, leading to the development of the Analytical Weights GSI (AW-GSI) strategy. This method uses the structure of the network and the nominal reconstructed state to generate a new set of graph weights, which are then used to configure a quadratic programming problem, analogue to GSI. Furthermore, additional sensor types, such as flow sensors or demand meters, are not considered by GSI or AW-GSI to improve the estimation process. Therefore, various sensor fusion strategies are conceived, leveraging the Unscented Kalman Filter algorithm, leading to the UKF-GSI estimation approach. This process is coupled with LCSM in order to improve leak localization.Finally, the sensor placement problem is also explored through a model-free perspective. This strategy uses genetic algorithms (GA) to minimize a structural metric related to node-sensor distances. The GA-based operations are customized for the problem at hand, and premature convergence countermeasures and stopping conditions are defined in order to lead to suitable sensor placement solutions.All the proposed methodologies are tested using the L-TOWN benchmark from the BattLeDIM2020 challenge, which consisted in a leak detection and localization competition with several international teams. In this thesis, an initial comparison between GSI-LCSM and a model-based method is provided, leading to conclusions about the advantages of each category of methods. Then, all the proposed improvements to GSI-LCSM are compared to the base methodology, demonstrating the suitability of the methods and analysing the advantages that each one adds to GSI-LCSM.
  

DOCTORAL DEGREE IN EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS

• RODRÍGUEZ SÁNCHEZ, JULIO: Nonlinear Identification of Underground Seismic Ground Motions From Surface Records
  
  Author: RODRÍGUEZ SÁNCHEZ, JULIO
  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: 19/12/2024
  Deposit END date: 14/01/2025
  Thesis director: LOPEZ ALMANSA, FRANCISCO | LEDESMA VILLALBA, ALBERTO
  Thesis abstract: In earthquake engineering, generally only surface records are available; therefore, the motion of the lower soil layers must be estimated by depropagation analysis. Underground accelerograms are relevant in earthquake-resistant design of structures with buried parts, in irregular terrain, in earthquake-triggered landslides, and in soil-structure interaction, among other situations. These considerations highlight the relevance of the problem analyzed; regarding its mathematical formulation, if the soil behavior is nonlinear, it is far from trivial.The common practice in Earthquake Engineering consists of using a deconvolution process for obtention of ground motion at the base of the numerical model used for seismic analysis of underground structures. The drawback of this method is that, as it is carried out in the frequency domain, it cannot simulate the variation of the nonlinear characteristics of the soil during seismic excitation, but it hypothesizes that the mechanical properties of the soil are invariant for its whole duration. This leads to inaccurate calculation of excitation at lower soil layers that are especially acute when the soil column is weak or earthquakes are strong.This thesis presents an algorithm to accurately estimate, from surface records, the motion of the lower soil layers considering nonlinearity in soil nonlinear behavior by a modified Masing model. The proposed algorithm is 1D and the soil domain to be analyzed is discretized in layers; the ensuing equations of motion are solved in discrete time using the Newmark method. Given that this problem is numerically ill-conditioned due to the singularity of the mass matrix, a nonlinear Bayesian Kalman Filter-type method is used to estimate the solution.Soil propagation software is developed in Python programming language, incorporating state-of-the-art considerations about numerical simulation of soil behavior under seismic loading. This program is tested against closed-form solution for vibration of soil columns and site response analysis conducted using the widely used DEEPSOIL program to check its accuracy in computation of soil profile behavior under seismic conditions with satisfactory results.Then, the soil propagation software is coupled with the Unscented Kalman Filter algorithm to identify the input excitation at bedrock given the acceleration record at site surface. Several variations of this Bayesian filter are explored. Results of identification from both closed-form solutions for vibration of soil columns and site response analysis carried out with DEEPSOIL suggest that the proposed back-analysis algorithm for the obtention of acceleration time series at bedrock given surficial measurements is accurate, especially when compared to the deconvolution procedure.Finally, a sample underground structure modeled in PLAXIS2D is subjected to two ground motions at base: one is a deconvolved motion and the other is a depropagated accelerogram obtained through the identification process developed in this research. Difference in resulting structural forces from both records highlights the importance of adopting nonlinear algorithms for determination of input excitation at base for an adequate and safe design of underground structures.
  

DOCTORAL DEGREE IN ELECTRONIC ENGINEERING

• GHODRATI, MOJTABA: NEGATIVE-SEQUENCE VIRTUAL CIRCUIT BREAKER
  
  Author: GHODRATI, MOJTABA
  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: 11/12/2024
  Deposit END date: 24/12/2024
  Thesis director: CASTILLA FERNANDEZ, MIGUEL | BORRELL SANZ, ÁNGEL
  Thesis abstract: Inverter-based microgrids are essential for integrating renewable energy sources and maintaining high power quality in distributed generation systems. However, unbalanced faults can induce negative-sequence currents and voltage imbalances, which significantly affect power stability and the operation of critical equipment. Conventional and solid-state circuit breakers, while capable of isolating faulted sections, face limitations in addressing these imbalances, especially in managing synchronization and power quality during disturbances.This thesis introduces a novel solution—the Negative-Sequence Virtual Circuit Breaker (NSVCB)—designed to prevent the propagation of negative-sequence components in islanded microgrids. Unlike traditional circuit breakers, the NSVCB eliminates negative-sequence currents and voltages at the point of common coupling (PCC) between microgrids without physically disconnecting sections of the grid, ensuring continuous power supply and frequency stability. The proposed NSVCB control scheme integrates advanced compensators with plug-and-play functionality, optimizing energy distribution and enhancing system resilience.This thesis is structured to comprehensively address the problem of negative-sequence currents and voltage imbalances in inverter-based microgrids, focusing on the development and validation of a Negative-Sequence Virtual Circuit Breaker (NSVCB). The document begins with an Introduction, which outlines the significance of power quality challenges in microgrids, particularly with respect to faults and imbalances, and reviews the limitations of conventional and solid-state circuit breakers.The next section, Modelling Asymmetrical Power Systems, presents a detailed methodology for analysing asymmetrical faults, using an illustrative example. Following this, the Control Proposal section defines three key control objectives—elimination of negative-sequence currents, improvement of power quality at the Point of Common Coupling, and maintaining power balance across inverters. A proposed control scheme for the NSVCB is also outlined here.In the Control Design section, the dynamic model of the closed-loop system is developed, with a focus on gain design and stability analysis, incorporating techniques such as the Nyquist criterion. The Experimental Results validate the proposed control system using a laboratory setup, comparing the NSVCB's performance with conventional circuit breakers, and demonstrating its advantages in mitigating negative-sequence currents without disconnection. The thesis concludes by summarizing the key findings and confirming the NSVCB's effectiveness in maintaining power quality and stability in microgrids.
  

DOCTORAL DEGREE IN ENGINEERING, SCIENCES AND TECHNOLOGY EDUCATION

• BERTOL GROS, ANA: Between rigor and imagination. Creativity in structures education
  
  Author: BERTOL GROS, 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 ENGINEERING, SCIENCES AND TECHNOLOGY EDUCATION
  Department: Institute of Education Sciences (ICE)
  Mode: Normal
  Deposit date: 13/12/2024
  Deposit END date: 08/01/2025
  Thesis director: LÓPEZ ÁLVAREZ, DAVID | BARDÍ MILÀ, BERTA
  Committee:
       PRESIDENT: COUSO LAGARÓN, DIGNA
       SECRETARI: ALIER FORMENT, MARC
       VOCAL: LLORENS LARGO, FARAÓN
  Thesis abstract: Creativity has been defined as a 21st century competence.In engineering, creativity is a vital component for the success and advancement of the profession. It enables engineers to view challenges from new perspectives, generate original and practical ideas, pose novel questions, and devise solutions to complex problems. This competence fosters interdisciplinarity, allowing professionals to collaborate within various fields to develop comprehensive projects that adhere to regulations and standards without sacrificing functionality or aesthetics. Teaching creativity to engineers is essential, as it equips them to devise innovative solutions, adapt to emerging technologies, enhance sustainability, and excel in a competitive job market.Traditionally, engineering education has been structured with methodologies centered on theoretical lectures and exercises with single answers. These studies, organized in silos with rigorous curricula, leave little room for exploration. Therefore, to promote creativity, educational methodologies must be adapted to the cognitive processes of university students and to the real demands of the profession and society.This doctoral thesis focuses on the field of structures, positioned at the intersection of engineering and architecture. This unique context presents an opportunity to explore creativity and contribute innovative ideas to enhance engineering education. The objective of this work is to analyze the theories, perspectives, and methodologies used in teaching structure courses to improve creativity in engineering education. By concentrating efforts in this area, the doctoral thesis aims to achieve reproducible and applicable results that can advance the field of engineering education.This work, based on a qualitative research paradigm, is structured on three pillars. The first is a literature review defining this thesis’s theoretical framework, synthesizing results from five areas relevant to creativity. Results show that, in higher education, effective creativity combines this innate skill with specific field knowledge. In engineering, this involves explaining the creative process to solve real problems. Research shows everyone has creative potential, but it must be fostered through education.The second pillar examines professional perspectives on creativity in engineering. Interviews with experts in structures reveal their opinions on integrating creativity in higher education. While there is agreement on general aspects of creativity, opinions diverge in the field of structures. Some professors question the need for creativity in their field, often due to time constraints that prevent the exploration of new teaching methodologies.The third pillar comprises field experiences. To understand the study environment, three research stays were conducted at European universities. In addition, two teaching innovation projects were carried out at the home institution. The results show that improving the design of the engineering curriculum requires collaboration and diverse teaching methodologies, the most recommended being thinking with your hands.Throughout this research, it has been discovered that there is a crucial need to provide accessible and adapted guidelines that can be applied by all educators in the discipline, regardless of their experience in creativity. The results of this research converge in the creation of nine practical guidelines to guide the development of creativity in structures. By implementing these results, engineering education can reshape the perception of creativity and demonstrate its tangible value in engineering practice. Creativity should not be seen as a separate entity but integrated throughout the curriculum, permeating all aspects of the student's educational itinerary. This requires a concerted effort by all staff involved in these teachings, where each person must play a fundamental role in fostering a culture of creativity.
  

DOCTORAL DEGREE IN MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING

• NUÑEZ LABIELLE, ALEJANDRO: Towards shock absorbing hyperelastic metamaterial design
  
  Author: NUÑEZ LABIELLE, ALEJANDRO
  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: 19/12/2024
  Deposit END date: 14/01/2025
  Thesis director: CANTE TERAN, JUAN CARLOS | OLIVER OLIVELLA, FRANCISCO JAVIER | CANTE TERAN, JUAN CARLOS | OLIVER OLIVELLA, FRANCISCO JAVIER
  Thesis abstract: This thesis explores the possibilities and benefits of computational tools to be used in the analysis and design of shock absorbing metamaterials for industrial applications. The research is organized into two complementary chapters. The first part focuses on the computational modeling of shock propagation in hyperelastic materials, emphasizing its importance in analyzing and designing mechanical energy-absorbing materials. This approach is categorized as shock-capturing, as it aims to capture the effects of shock formation and propagation on the mechanical response of the solid. Numerical simulation of the onset and propagation of discontinuous strain waves (mechanical shocks) across a solid is performed in that specific approach, and it is computationally assessed in different loading situations. The concept of extrinsic dissipation, emerging from the breaking of polyconvexity constraints in hyperelastic materials, is recalled and exemplified via a large strain neo-Hookean polyconvex hyperelastic model which is perturbed in a number of different formats. The obtained mechanical responses, exhibiting propagating mechanical shocks, and the corresponding extrinsic dissipation, are explored together with the inherited computational issues, by means of representative numerical examples. Additionally, the problem of the dynamic impact of a rigid solid on low-density shock-absorbing specimens made of these perturbed hyperelastic materials is analyzed, and the amount and time-evolution of the resulting extrinsic dissipation are evaluated to characterize their performance for shock-absorbing purposes. Furthermore, the exhibited property of shape recovery after impact is highlighted as a distinctive feature in front of alternative shock-absorbing materials. The second part of the thesis explores the potential of computational multiscale methods, in conjunction with massive buckling-lattice structures at the metamaterial core (meso/micro scale), to provide a suitable framework for designing shock-absorbing metamaterials aimed at industrial applications. In this context, a prospective computational setting is considered under the hypothesis that, for a sufficiently complex microlattice topology, some localized regions might buckle within the lattice-structure core and propagate through it, giving rise to different loading-unloading paths, in such a way that hysteretic-like structural behaviors would take place, thus arising dissipative behaviors, even if the base material at the buckling micro-lattice behaves in a hyperelastic (thus intrinsically non-dissipative) manner. Using the standard Hill-Mandel homogenization principle, and assuming that the necessary separation of scales holds, the homogenized body, now living in a classical solid-mechanics setting, displays a homogenized non-convex behavior which exhibits extrinsic dissipation and, thus, could be potentially used (at reduced computational cost) for shock absorbing metamaterials analysis and design purposes. A tentative industrial application, to a sneaker’s insole design, has been then considered as a work’s target for evaluation of the room offered by the explored setting in the context of shock-absorbing metamaterial design. Finally, remarks on the scope and limitations of the work, and its significance for further advances in the field are emphasized.
  

DOCTORAL DEGREE IN PHOTONICS

• ZARRAOA SARDÓN, LAURA: Photon counting with a single neutral atom: quantum efficiency, dark counts, and background rejection
  
  Author: ZARRAOA SARDÓN, LAURA
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN PHOTONICS
  Department: Institute of Photonic Sciences (ICFO)
  Mode: Normal
  Deposit date: 05/12/2024
  Deposit END date: 19/12/2024
  Thesis director: MITCHELL, MORGAN | VEYRON, ROMAIN
  Thesis abstract: This thesis studies the use of a single trapped neutral 87Rb atom as a photon counter. Detection of quantum jumps (QJs), i.e., abrupt changes between atomic states observable by a change in atomic fluorescence, is used to infer the arrival of single photons. This is referred to as the quantum jump photodetection (QJPD) technique.The thesis first situates QJPD in the context of photodetection. Compared to traditional detectors, QJPD technique has lower speed and quantum efficiency (QE), but has exceptional performance in other figures of merit: QJPD is intrinsically narrowband, has strong out-of-band rejection, and very low dark counts (DCs). These features make the QJPD interesting for applications that detect weak optical signals in the presence of a strong broadband background.Experimental methods to study QJPD are described. A 87Rb atom is loaded from a magneto-optical trap (MOT) into a far-off resonance trap (FORT) at the center of four orthogonal, co-focal, high numerical aperture lenses. These lenses create the FORT, couple probe light onto the atom and collect the atomic fluorescence, which is used to identify the atomic state. A typical QJPD sequence is presented, which consists of trapping and cooling an atom in the FORT, optically pumping it into the dark state, illuminating with probe light, illuminating with readout light and collecting fluorescence photons, and checking that the atom has not left the FORT during the sequence.Statistical methods for measurement of QE and DC contributions are introduced. These compare the observed fluorescence count distribution against measured hyperfine-state fluorescence distributions. A QE of (2.4±0.1)×e−3 is demonstrated, a record for single photon absorption by a single atom in free space.Dark count contributions are measured. To produce low DC, the QJPD technique is implemented in two time windows: an exposure time for the single photon absorption followed by a short fluorescence time to read out the atomic state. This implies distinct acquisition and readout DC contributions, similarly to CCD and CMOS detectors. A dark jump rate (analogous to CCD/CMOS dark current) is measured of (5 ± 10) × e−3 jumps/s, consistent with zero and limited by measurement statistics. The measured readout contribution is (4.0 ± 0.4) × e−3 jumps per ms of fluorescence readout. For a 1 Hz readout rate, with 1 ms readout pulses, a net dark count rate of (15 ± 10) × e−3 counts/acquisition is demonstrated, which is already competitive with any non-cryogenic detector.The background rejection capabilities of the system are tested by measuring quantum jump rates when the atom is illuminated with direct sunlight, and with light scattered by the atmosphere (skylight). A rate equation model is developed to describe QJ probabilities in the presence of both intense broadband background and weak resonant probe light. This model is used to interpret experiments in which a weak signal beam competes with strong broadband background and validated using direct sunlight. Measurements where the atom is illuminated with skylight show no observable background-induced QJs. Finally, measurements of sky brightness and its fluctuations are presented, showing large fluctuations even on mostly clear days, a factor that further increases the need for background rejection.A number of contemporary applications of extreme photodetection, including free-space quantum communication in daylight, classical optical communications in space, and fundamental physics experiments, are discussed as possible applications of the QJPD technique. A realistic scenario where the demonstrated QJPD capabilities surpass the current performance of commercial single photodetectors is presented.Finally, potential improvements are discussed. It is shown that existing atomic and optical technologies could be applied to reach different wavelength ranges, narrower bandwidths, higher quantum efficiency, and lower dark counts.
  

DOCTORAL DEGREE IN STATISTICS AND OPERATIONS RESEARCH

• MAUREIRA ALEGRÍA, GRACE KELLY: A Multi-Objective Integer Programming Approach for Synergistic Tenant Mix Optimization in Shopping Centers
  
  Author: MAUREIRA ALEGRÍA, GRACE KELLY
  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 STATISTICS AND OPERATIONS RESEARCH
  Department: Department of Statistics and Operations Research (EIO)
  Mode: Normal
  Deposit date: 16/12/2024
  Deposit END date: 09/01/2025
  Thesis director: HEREDIA CERVERA, FRANCISCO JAVIER
  Thesis abstract: A shopping center's profitability is significantly influenced by its Tenant Mix, which refers to the strategic combination and placement of different retail categories within the center. However, selecting the optimal Tenant Mix has traditionally been based on experience and intuition rather than data-driven approaches. This study addresses this gap by developing a systematic, data-driven optimization model aimed at maximizing profitability through optimal tenant placement.The methodology used in this research involves the development of a Multi-Objective Integer Programming model. This optimization model aims to maximize the combination of three components in its objective function: rental income, sales revenues, and tenant synergy. Constraints are related to the leasable area available for each retail category and the synergistic configuration influencing tenant placement. The data analyzed comes from 27 shopping centers managed by CBRE Spain, covering the period from 2015 to 2022, with the exclusion of 2020 due to the temporary closure of shopping centers during the COVID-19 pandemic.In order to incorporate rental income into the optimization model's objective function, a semi-log regression model was developed. The model considers the monthly rent per square meter as the dependent variable and factors such as store size, store location, tenant category, tenant’s sales per square meter, anchor status, distance to the nearest anchor, and shopping center type as independent variables. The empirical analysis identified that store size, location, anchor status, and retail category significantly affect rental rates. Notably, stores on lower floors tend to command higher rental rates compared to those on upper floors, while the distance to the nearest anchor tenant does not significantly affect rental values.One of the key contributions of this research is the incorporation of tenant synergy into the optimization model, which captures the beneficial interactions between neighboring tenant categories. By analyzing historical data from the 27 shopping centers, specific configurations of neighboring retail categories were identified as having the potential to enhance sales revenues. These configurations were scored based on their impact on sales, and the model aims to maximize these synergy scores, along with rental income and sales revenues, to achieve the most profitable Tenant Mix.The optimization model was applied to six shopping centers: one from each cluster, with one analyzed in greater depth. Three scenarios were evaluated: "Last Layout," "Only Vacancies," and "From Scratch." In all scenarios, the model used 50 combinations of weighted objectives, producing a three-dimensional Pareto frontier. In the "Last Layout" scenario, the model was applied only to the occupied units in the latest tenant configuration (as of December 2022). For smaller centers, rent and sales were lower, but synergy improved, while larger centers saw overall gains in rent, sales, and synergy.In the "Only Vacancies" scenario, the model optimized unoccupied units, keeping the current Tenant Mix unchanged. Results confirmed that the synergistic configurations derived from historical layouts provided optimal solutions, demonstrating the model's flexibility. The "From Scratch" scenario involved a complete reconfiguration, with rent and sales remaining stable across the 50 combinations but greater variability in synergy. This scenario offers strategic insights for landlords aiming to reimagine Tenant Mix for improved financial performance and synergy.The encouraging results highlight the model’s practical utility and strategic potential for retail space management, making it a reliable tool for optimizing the Tenant Mix in shopping centers. Landlords can leverage the insights from this model to make informed decisions about tenant selection and placement that align with their long-term objectives.
  

DOCTORAL DEGREE IN URBANISM

• FIOL DURAN, VICTÒRIA INMACULADA: A Mallorca, S'Arenal. Dibuixos d'un paisatge encobert. Traçats per a un nou model territorial.
  
  Author: FIOL DURAN, VICTÒRIA INMACULADA
  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: 17/12/2024
  Deposit END date: 10/01/2025
  Thesis director: EIZAGUIRRE GARAITAGOITIA, FRANCISCO JAVIER | CORTELLARO, STEFANO
  Committee:
       PRESIDENT: PARCERISA BUNDO, JOSEP
       SECRETARI: GALINDO GONZALEZ, JULIAN
       VOCAL: SIMÓN ROJO, MARIAN
       VOCAL: ANASTASIA, CATERINA
       VOCAL: HORRACH ESTARELLAS, GABRIEL PERE
  Thesis abstract: Platja de Palma, Mallorca, is a strategic place for its combination of natural attractions and its geographical location, as well as being a clear setting for the construction and transformation of the pre-existing landscape. This is not only due to its having been one of the laboratories in which to experiment with tourist landscapes, but also as it has had a leading role in some of the main actions to improve seasoned tourist destinations over recent years.All these actions aim to rebuild a territory that was once idyllic for summer holidaymakers and which conserves hidden qualities, with risks and threats for the future, but hidden qualities that are able to be restructured.This doctoral thesis aims to analyse, describe, identify, develop and classify the territory of Platja de Palma based on its free open spaces ¤C squares, parks, woodland, residential areas, sand and beaches ¤C in their original state and it considers the evolution of the elements which remain, which are transformed, which disappear, which are grouped together or which become dispersed, for example. In other words, it aims to understand the structure of the countryside and strike a balance between that which has been constructed and that which has not. It will take the concept of ¡°constructed¡– in the most literal sense of the word, but at no point will it consider non-urban or urbanised space as exempt from form, construction or use. In fact, the whole territory is a space constructed to different extents and this research shows that less density and solidity in constructed areas implies greater value.This updated project aims to explore new ways to continue sharing tourism, which is here to stay, as well as the landscape supporting it.This research project also intends to use the methodology of zoning, classification and the nomenclature of public spaces and their systems, as trialled and applied in conventional urban planning. It is therefore clear that the coastal territory is unique and that it is necessary to offer specific features for the new systems of unoccupied spaces and their dynamics within the territory of S’Arenal, which are always linked to supporting its landscape.The features retained aim to better understand the particular features of open spaces in the coastal territory of Platja de Palma. These features are key to creating structures which readjust the existing territorial model together with a study of their relationships and interactions of the support analysed. Today there are new challenges to be faced with the intrinsic objective of using mapping.Maps and plans are descriptions referring to territories¡fl and cities¡fl pasts and presents. They are also interpretations that speak of the conception of the space and the relationships that residents establish with it. They go beyond being a mere representation of what is known, making way for unknown elements, values and relationships to appear. They anticipate and induce changes to the landscape and project the future. They will therefore condition the future regeneration developments and modifications to Platja de Palma.In short, the relevance of the biogeophysical support determining development is recognised. The network will address flow management and improve the permeability of the current limits, as well as transitions between urban and rural uses. It will also sketch out a well-balanced blend of forests, agriculture and cities integrated into a sequence of landscapes all the way to the sea. It is only by restoring the metabolic cycles of the land and water, and increasing biodiversity and reinforcing its environmental function, that Platja de Palma can be transformed into S¡flArenal: a privileged area combining urban, rural and agricultural values to restore a typical landscape.