Doctoral School

Reading date: 27/01/2026

• BOSCH PADRÓS, MIQUEL: Optogenetic control of force transmission in puripotent epithelia
  
  Author: BOSCH PADRÓS, MIQUEL
  Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
  Programme: DOCTORAL DEGREE IN APPLIED MATHEMATICS
  Department: School of Mathematics and Statistics (FME)
  Mode: Normal
  Deposit date: 16/12/2025
  Reading date: 27/01/2026
  Reading time: 15:00
  Reading place: Sala d'Actes de l'FME, Edifici U, Campus SudEnllaç MEET: meet.google.com/wda-kfee-saf
  Thesis director: ARROYO BALAGUER, MARINO | TREPAT GUIXER, XAVIER
  Thesis abstract: Development requires a combination of three phenomena: increasing the number of cells, specifying their fates and undergoing morphogenesis, which means acquiring the correct shapes. Apical constriction is an important driving mechanism of morphogenesis, occurring within a cell but bridging with tissular scale to acquire and maintain shape. Apical constriction is well studied at the cellular level and conserved through the animal kingdom, but the forces that need to be generated and transmitted through the tissue in the process have never been measured and described. To fill this gap, we used a novel optogenetic tool to induce apical constriction in human pluripotent stem cells, combined with traction force microscopy to measure the mechanical forces involved in the process. With this techniques, we discovered that constriction creates a consistent but small signature in traction maps, compatible with apical contractility increase and volume conservation. In addition, we subjected regions of a monolayer to apical constriction and revealed that the cellular displacement field obeys a screened Poisson equation in two dimensions, which implies the existence of a lengthscale with a rheological origin and allows to obtain the Green's function of the tissue. While deformations can be tailored in space and time, we also find that jamming transitions cannot be engineered through apical contractility, which exposes a strong unjammed nature of this pluripotent epithelium. These insights reveal key rheological aspects of human pluripotent stem cells at timescales relevant for morphogenesis, inaccessible through other techniques. Because this cells are used around the globe to derive organoids and embryo models but are highly understudied mechanically, this work establishes a key building block for future works that require shape or force control in stem cell-derived tissues.
  

• CHEN, MINGRUI: State of Charge Estimation for Metal Hydride Storage Tanks
  
  Author: CHEN, MINGRUI
  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: 17/12/2025
  Reading date: 27/01/2026
  Reading time: 16:00
  Reading place: Aula 28.8 de l'Escola Tècnica Superior d'Enginyeria Industrial de Barcelona (ETSEIB), Edifici PI (Pavelló I). Av. Diagonal, 647, 08028 Barcelona
  Thesis director: COSTA CASTELLO, RAMON | NA, JING
  Thesis abstract: The growing global energy demand and the urgent need for sustainability have highlighted hydrogen as a clean energy carrier. Among various storage methods, metal hydride (MH) tanks are promising due to their high volumetric density, safety, and reversible absorption/desorption properties. However, complex thermodynamics, kinetic hysteresis, and unobservable internal states make accurate real-time estimation of the state of charge (SOC) challenging. Reliable SOC estimation is essential for efficient operation, safety, and integration with renewable systems.This thesis applies nonlinear observer theory to estimate the SOC of MH tanks. A comprehensive physical model is first developed based on mass and energy balances and reformulated into 3D and reduced 2D state-space models, including a modified version accounting for pipeline effects. Parameter identifiability and sensitivity analyses are performed to ensure model reliability, followed by parameter calibration using experimental data and optimization techniques such as particle swarm and multi-objective optimization.Several nonlinear observers are then designed for real-time SOC estimation. These include a Luenberger-like observer, a neural network-based inversion estimator for reduced computation, and switched nonlinear observers addressing the mode-dependent behavior of MH tanks. Stability and convergence are guaranteed through differential detectability and contraction theory.Numerical simulations and experiments on commercial MH tanks demonstrate that the proposed models and observers provide accurate, robust, and computationally efficient SOC estimation, offering a practical foundation for intelligent hydrogen storage management.
  

• CHIEN, YING-HAO: Revealing Ultrafast Dynamics in Hexagonal Boron Nitride with Attosecond X-ray Absorption Fine-structure Spectroscopy
  
  Author: CHIEN, YING-HAO
  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: 16/10/2025
  Reading date: 27/01/2026
  Reading time: 10:00
  Reading place: ICFO Auditorium
  Thesis director: BIEGERT, JENS
  Thesis abstract: Since the invention of the integrated circuit (IC) in the 1950s, modern civilization has been built upon its foundation. As ICs continue to scale down and operate at higher speeds, managing heat dissipation and energy transfer process is critical to overcoming performance limitations and enabling the development of next-generation ICs. In classical models, electrons and phonons are treated as independent systems to simplify calculations. This approximation successfully describes electronic band structures, charge transport, and optical responses in many materials under equilibrium conditions. However, it neglects the critical role of electron-phonon coupling, a fundamental many-body interaction that governs non-equilibrium energy exchange between electronic and lattice degrees of freedom. Recent advances in attosecond X-ray absorption fine structure (atto-XAFS) spectroscopy offer an unprecedented opportunity to observe electron-phonon coupling dynamics with both attosecond temporal and element-specific resolution. Hexagonal boron nitride (hBN), a widely studied prototypical material with diverse applications, still presents unresolved questions regarding its ultrafast dynamics. In this work, we investigate the coupled electron and phonon dynamics in bulk hBN using atto-XAFS. By employing different excitation conditions and exploiting different temporal resolutions, we disentangle the respective contributions of electrons and phonons to the transient response, demonstrating the unique capability of atto-XAFS to probe many-body dynamics in real-time. To enable further studies of novel materials, we upgraded our titanium-doped sapphire (Ti:sapphire) chirped pulse amplification (CPA) laser system, integrated a new commercial TOPAS optical parametric amplifier, designed a novel microfluidics gas target combined with a piezo pulse valve system aimed at reducing helium consumption for high harmonic generation (HHG), implemented a cryogenic sample mount for temperature-dependent measurements, and replaced the diffraction grating in the soft X-ray spectrograph with high diffraction efficiency and high resolving power reflection zone plates. We demonstrate the enhanced performance of the upgraded system for future advanced atto-XAFS experiments.
  

Reading date: 28/01/2026

• ALCAYDE ROMO, BARBARA: Numerical modelling of the fatigue behaviour of composites. Application to the automotive industry.
  
  Author: ALCAYDE ROMO, BARBARA
  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 STRUCTURAL ANALYSIS
  Department: Department of Civil and Environmental Engineering (DECA)
  Mode: Normal
  Deposit date: 19/12/2025
  Reading date: pending
  Reading time: pending
  Reading place: pending
  Thesis director: BARBU, LUCIA GRATIELA | CORNEJO VELÁZQUEZ, ALEJANDRO
  Thesis abstract: In an engineering landscape increasingly focused on optimized design, lightweight materials, and multifunctional performance, accurately predicting the fatigue behaviour of composite materials under realistic service conditions is essential. Traditional approaches to fatigue analysis in Fibre Reinforced Polymers (FRP) often rely on simplified extrapolations of laboratory data or homogenized models that neglect the complex interactions between constituent materials and environmental influences. Moreover, these approaches typically fail to account for temperature variations. Such reductionist perspectives limit the ability to capture the coupled mechanical and thermal degradation mechanisms inherent to advanced materials. This thesis proposes a unified numerical framework grounded in the Finite Element Method (FEM), integrating a phenomenological homogenization strategy, the Serial Parallel Rule of Mixtures Law (SP-RoM), with a High Cycle Fatigue (HCF) Constituive Law (CL). This approach enables the simultaneous representation of the distinct fatigue responses of fibres and matrix within layered composite laminates, accounting for variations in stacking sequence and fibre orientation. A key innovation is a calibration methodology that infers fatigue parameters at constituent level from experimental data at laminate scale, thus overcoming the challenges of direct testing of individual components. Furthermore, the work presents a thermomechanically coupled fatigue model incorporating temperature dependent material properties and thermal expansion, generalizing classical fatigue life prediction curves to fluctuating and spatially varying temperature fields. To address the significant computational demands of fatigue simulations, an Advance in Time Strategy (AITS) Cycle Jump (CJ) is developed, enabling efficient simulation of long-term fatigue damage evolution without sacrificing accuracy. Validated against experimental benchmarks and literature data, the proposed methodology advances fatigue life prediction in composite materials by delivering a flexible, robust, and computationally efficient tool. Additionally, the fatigue formulation has been enhanced to capture complex thermomechanical effects. This work lays the foundation for future research on integrated modelling of fatigue and multiphysics deterioration phenomena in advanced composite structures.
  

• ALCÓN DOGANOC, MIGUEL: Verification and Validation Solutions for the Safety Compliance of Autonomous Driving Frameworks Performance Aspects
  
  Author: ALCÓN DOGANOC, 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 COMPUTER ARCHITECTURE
  Department: Department of Computer Architecture (DAC)
  Mode: Normal
  Deposit date: 01/12/2025
  Reading date: 28/01/2026
  Reading time: 11:00
  Reading place: C6-E101
  Thesis director: ABELLA FERRER, JAIME | MEZZETTI, ENRICO
  Thesis abstract: Autonomous Driving (AD) has rapidly evolved from a research concept into an industrial reality. The increasing computational demands of autonomous vehicles have motivated the use of high-performance Multi-Processor Systems-on-Chip (MPSoCs), which offer both performance and energy efficiency. However, ensuring the safety compliance of such complex systems remains a major challenge. The software frameworks used to implement AD functionalities—typically integrating Artificial Intelligence (AI) algorithms—are not designed following a safety-driven development processes, and their non-deterministic behavior conflicts with the strict determinism required by safety standards. This thesis addresses these challenges by developing Verification and Validation (V&V) solutions that improve the safety compliance of AD frameworks, with a particular focus on performance-related aspects.The thesis begins by analyzing the main sources of non-determinism in AD systems across three layers: algorithmic, software architectural, and hardware platform. While variability exists in all layers, the software architecture layer is identified as a key contributor to the overall unpredictability. It not only introduces its own sources of variability but also amplifies those inherited from the other layers. This makes software architecture an effective focal point to improve system determinism and safety assurance.At the foundational level, the thesis addresses the challenge of unit testing within already-integrated AD frameworks, using the open-source Apollo AD framework as a case study. Due to tight coupling and data dependencies among its modules, Apollo does not easily support independent module validation. To enable proper verification of software units, the thesis proposes a systematic methodology to isolate, modify, and reconfigure Apollo modules into standalone, testable units, thus reintroducing unit-level testing capabilities into a complex, AI-based AD framework.The work advances toward system-level safety assurance through the development of dynamic and execution views of Apollo. Dynamic views describe the interactions among software components, linking safety requirements with their implementation and validation tests. However, these views alone fail to capture the concurrent behavior and execution parallelism of the system, which are crucial for verifying performance-related safety requirements. To fill this gap, the thesis introduces execution views, which complements dynamic views by integrating runtime information gathered from execution tracing on MPSoC platforms. Execution views enhance the observability of resource usage, timing behavior, and concurrency, allowing both improved testing and optimized hardware utilization—key aspects for reducing cost and ensuring safety.Finally, the thesis addresses the timing behavior and variability across software components. It identifies, formalizes, and applies a comprehensive set of timing-related metrics capable of capturing inter-module interactions and end-to-end latency properties in AD applications. Traditional timing metrics, such as worst-case execution and response times, fail to capture the interdependencies between components in systems like Apollo. By adopting complementary metrics such as maximum reaction time and maximum time displacement, the proposed approach provides deeper insights into timing dependencies, enabling early detection of timing anomalies and improving validation confidence.Overall, this thesis provides a set of methodologies and tools to improve the V&V of AD software from a safety-performance perspective. The proposed contributions bridge the gap between high-performance AI-based software and the stringent determinism required by safety standards. These advances support the systematic assurance of safety in AD frameworks, ultimately contributing to the reliable and certifiable deployment of autonomous vehicles on high-performance embedded platforms.