Author: TIMOTE BEJARANO, CRISTHIAN CAMILO
Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
Programme: DOCTORAL DEGREE IN AEROSPACE SCIENCE AND TECHNOLOGY
Department: Department of Physics (FIS)
Mode: Article-based thesis
Deposit date: 03/03/2023
Reading date: 27/03/2023
Reading time: 08:00
Reading place: Aula de Teleensenyament de la ETSETB UPC. Campus Nord, edifici B3- Enlace a la videollamada: https://meet.google.com/kwc-adhs-vdq
Thesis director: GONZÁLEZ CASADO, GUILLERMO | ESCUDERO ROYO, MIGUEL
Committee:
     PRESIDENT: GARCIA FERNANDEZ, MIQUEL
     SECRETARI: ARAGON ANGEL, MARIA ANGELES
     VOCAL: NIE, WENFENG
Thesis abstract: This document presents the collection of four manuscripts published during my Doctoral academic formation, which main goal has been the real-time implementation of tools to monitor the ionosphere using Global Navigation Satellite System (GNSS) signals. Despite the fact that there is a vast literature on ionospheric modelling, the state-of-the-art becomes narrow when referring to real-time developments, especially fulfilling precise requirements on accuracy, performance, coverage, and confidence in the generated products. The main contribution of this work to the scientific community is the deployment of ionospheric-related products to monitor in real-time the state of the ionosphere.The first and second publications targeted the implementation of a novel strategy based on a definition of a GNSS Solar Flare (SF) monitor to automatically confirm Solar Flare Effects (Sfe) in geomagnetism. In the first scientific article, it is inspected the methodology used to fine-tune (adapt) a SF monitor, working with an eleven years period of data to statistically correlate detected SF using GNSS signals with respect to SFe. The results demonstrated that the proposed GNSS Solar Flare monitor can confirm Sfe events when traditional Sfe detectors are not able to respond categorically. The second publication details the methodological approach for defining the proposed GNSS Solar Flare monitor, focusing on the theoretical formulation of the Slant Total Electron Content (STEC) obtained.The third contribution used GNSS signals to detect the presence of Medium Scale Travelling Ionospheric Disturbance (MSTID) within a network of permanent GNSS stations that provide the high-accuracy positioning service known as Network-Real-Time Kinematics (NRTK). The effects of a MSTID are characterized in terms of fluctuations in the electron density in the iono- sphere, experienced differently by each one of the GNSS stations used as reference receivers within the NRTK, and resulting in a degradation of the positioning of any user of the service. The MSTIDidx index is proposed to warn users of the presence of a MSTID, implementing a novel methodology for assessing the errors in positioning based on fixing carrier-phase ambiguities in undifferenced measurements. The adoption of the proposed MSTIDidx index proves to be efficient to reduce the errors on the user positioning by excluding measurements polluted by the MSTID effects, reaching accuracy levels within the overall network similar to the ones achieved by users located close to reference stations (and therefore, less affected by MSTID effects).The fourth publication is the core of my doctoral thesis and presents the real-time implemen- tation of a model to generate ionospheric corrections suitable to fulfill the Galileo HAS. The analyzed ionospheric correction system is based on the Fast Precise Point Positioning (FPPP) technique, in which it is highlighted the benefits of integer ambiguity resolution to obtain unambiguous carrier phase measurements as input to compute the FPPP ionospheric model. Additionally, this contribution underlines the benefit of the implemented strategy, in terms of the geometric model used by the ionospheric modelling and the dataset implemented. In terms of assessing the errors of the FPPP ionospheric corrections, the 99% of the Global Positioning System (GPS) and Galileo errors in well-sounded areas and in mid-latitude stations are below one total electron content unit, which is in line according to the required ionospheric accuracy for the Galileo HAS. Furthermore, alongside the ionospheric corrections, it is presented some additional products generated by the FPPP Central Processing Facility (CPF), produced in real-time and with accuracy levels suitable to any HAS application.

Author: DI GIULIO, VALERIO
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: 01/03/2023
Reading date: pending
Reading time: pending
Reading place: pending
Thesis director: GARCÍA DE ABAJO, JAVIER
Committee:
     PRESIDENT: KOCIAK, MATHIEU
     SECRETARI: ROPERS, CLAUS
     VOCAL: MANJACAVAS AREVALO, ALEJANDRO
Thesis abstract: Among the fundamental constituents of matter, charged particles such electrons and positrons are leading protagonists in physical phenomena associated with small (~ meV) and high (~ MeV) energy scales. For example, conductive electrons in condensed-matter systems can collectively respond to the action of an external electromagnetic field and sustain plasmon excitations that dominate their visible optical behavior. The presence of material boundaries produces a dramatic modulation of such modes, allowing us to mold their interaction with light for the exploration of fundamental phenomena and the design of practical applications, which are central themes in the field of nanophotonics.Electrons traveling in free space, such as those in electron microscopes, constitute ideal probes for imaging materials with nanometric resolution. In an effort to push energy resolution down to the meV regime and simultaneously perform time-resolved measurements with fs precision, laser and electron pulses in transmission electron microscopes can now be synchronized to meet at the specimen in the so-called photon-induced near-field electron microscopy (PINEM). Here, efficient electron coupling to intense laser-driven evanescent fields results in a strong energy reshaping of the electron wave function. Over the last decade, PINEM has been used to tailor the wave function of free electrons, thus emphasizing the role of these microscopy probes as information carriers. This Thesis lies in this general and broad context as an effort to explore new scenarios in the interaction between free electrons and optical excitations. In particular, Chapter 2 addresses the theoretical investigation of quantum-mechanical aspects associated with PINEM interaction by means of a quantum-optics description of the optical field. Building up on those results, in Chapter 3 we show that improved control over electron pulse shaping, compression, and statistics can be gained by replacing coherent laser excitation by interaction with quantum light, such as phase- and amplitude-squeezed optical fields.Chapter 4 explores the role played by fluctuations of the electromagnetic vacuum in the coupled dynamics of a free-electron beam and a macroscopic object, producing elastic diffraction and decoherence. In particular, we show that diffraction can dominate over decoherence, therefore suggesting a nondestructive approach to microscopy based on the specific choice of parameters that minimize the inelastic interaction with the specimen.As a radically different aspect of electron-light interaction, Chapter 5 is devoted to the study of the interference produced in the cathodoluminescence emission by the synchronized interaction of free electrons and dimmed laser pulses scattered by the specimen. Here, we argue that such effect may enable measurements combining the spectral and temporal selectivity of the light with the atomic resolution of electron beams to resolve the phase associated with optical modes in the sample.In Chapter 6, we consider that elastic diffraction, similar to that studied in Chapter 4, is also experienced by conduction electrons in a two-dimensional material, therefore altering the properties of the latter by simply adding a neighboring neutral structure.Going to higher energy scales, Chapter 7 explores the potential of confined optical modes to assist electron-positron pair production arising from the scattering of gamma rays by surface polaritons propagating along a material interface.In summary, throughout this Thesis we exploit the coupling between evanescent light, harnessed in the vicinity of material boundaries, and charged free particles in order to access new effects only found at the point where nanophotonics, quantum optics and high-energy physics meet through strong light-matter interaction.

Author: FINOCCHIARO, MARTINA
Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
Programme: DOCTORAL DEGREE IN BIOMEDICAL ENGINEERING
Department: Department of Automatic Control (ESAII)
Mode: Change of supervisor + Temporary seizure
Deposit date: 01/03/2023
Reading date: 28/03/2023
Reading time: 11:00
Reading place: Sala d'Actes Facultat d'Informàtica de Barcelona (FIB), Edifici B6 del Campus Nord, C/Jordi Girona, 1-3, 08034 Barcelona
Thesis director: CASALS GELPI, ALICIA | CIUTI, GASTONE | HERNANSANZ PRATS, ALBERTO | MENCIASSI, ARIANNA
Committee:
     PRESIDENT: VALDASTRI, PIETRO
     SECRETARI: MARTIN RULL, ENRIC XAVIER
     VOCAL: GINÉS GIBERT, MARIA DELS ÀNGELS
     VOCAL: WURDEMANN, HELGE
     VOCAL: CIUTI, GASTONE
Thesis abstract: Over the years, a continuous development of intraluminal procedures resulted in strong benefits for the patients. Reduced blood loss, lower risk of infections, diminished scaring impact and quicker recovery time are among the most valuable ones. However, these improvements imposed high mental and physical stress to the clinicians. In this context, the introduction of robotic technologies has resulted in notable improvements in terms of flexibility of the endoscopes and control stability, by designing multi-steerable snake like robots and endoscopic capsules. Robotic devices also introduced additional degrees of freedom (DOF) to control, as well as sensing information to process, posing the basis for a new framework of human-robot interaction. Therefore, in the context of intraluminal robotic surgery, the present research focuses on the human-robot interaction, aiming at investigating the optimal way to design Human Machine Interface (HMI) with multiple levels of assistance. Accordingly, a modular bio-engineering framework was designed and developed for the analysis, evaluation and comparison of different HMI for robot assisted endoluminal procedure (i.e., colonoscopy). The main component of the framework is a virtual simulator of the robotic colonoscopy procedure, developed using the SOFA. The simulator, endowed with 3D models of colons reconstructed from real patients' CT scans, realistically reproduces the anatomy and its performance during the robotic medical procedure in terms of timings, visual rendering and mechanical behaviour. Its open design allows to measure several metrics correlated with the quality of the procedure (e.g., force exerted on the intestinal walls, timings etc.) and of control (e.g., smoothness of trajectory). Therefore, the different HMI can be used to control the robotic endoscope in the virtual simulator and tested with user studies involving the endoscopists. This framework also comprises the use of wearable sensors to measure the cognitive load of the users through physiological data when testing the HMI in the simulation environment. Finally, a set of questionnaires were designed to be filled by the subjects after the tests for measuring their perceived physical and mental stress, and their overall impression on the interfaces. The framework was tested for the first time by 42 clinicians with the goal of deriving the optimal device for teleoperated control of robotic colonoscopes. To this end, a preliminary survey was driven among 71 endoscopists to derive the main characteristics and configuration of the control device desired by the final users. Accordingly, two selected systems were compared with the framework: an haptic serial-kinematic device and a standard videogame joypad. This users' test represented a first case study for the validation of the framework allowing to compare different HMI and derive their optimal features. Nevertheless, being the framework highly modular and open, is meant to be applied for the testing of different aspects of the HMI, both software and hardware e.g., types of feedback, control strategies etc. Indeed, the final goal of the framework, and more in general of the present thesis, is to extract insights, guidelines and metrics over the design of the next generation intraluminal robotic devices.

Author: MUÑOZ LA RIVERA, FELIPE
Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
Programme: DOCTORAL DEGREE IN CIVIL ENGINEERING
Department: (DECA)
Mode: Article-based thesis
Deposit date: 17/02/2023
Reading date: 28/03/2023
Reading time: 11:00
Reading place: ETSECCPB, mòdul C2, aula C1-002, Barcelona, Campus Nord (C/ Jordi Girona 1-3)
Thesis director: OÑATE IBAÑEZ DE NAVARRA, EUGENIO | MORA SERRANO, FRANCISCO JAVIER
Committee:
     PRESIDENT: GONZÁLEZ GARCÍA, MARÍA DE LAS NIEVES
     SECRETARI: FORCADA MATHEU, NURIA
     VOCAL: FONSECA ESCUDERO, DAVID
Thesis abstract: Cycles in the construction sector and economy disguise what appears to advance in occupational risk prevention when, unfortunately, the AECO sector maintains very high accident rates. The zero accident target is the most important indicator of robust implementation of accident safety. This objective implies that organisations and workers cover the whole spectrum of circumstances, from reactive measures to proactive design practices and developing a culture of prevention. The technological and methodological renewal of the industry through paradigms such as Building Information Modelling (BIM) and the deployment of Construction 4.0 represents a unique opportunity to work on occupational safety in depth, as a key dimension integrated into the construction process and not as a complementary annexe to the project and the execution of the work.Extended Reality (XR), understood as the technology that provides the user interface for the visualisation, immersion and interaction with the digital content of construction projects, is a central element in covering training, design and monitoring solutions for the new generation of workers who must use Construction 4.0 technologies. Some developments, both academic and commercial, show the potential of using XR experiences for construction safety. However, the adoption processes of the technologies require a reflection and technological framework to facilitate their use and massification, designing flexible and automatable workflows that allow the agile generation of XR content to deploy the culture above and design for prevention.The purpose of this doctoral thesis is to develop a framework for the generation of extended reality solutions for the holistic management of safety in construction, including both technological features interoperable with BIM information, data and dimensions, and methodological ones, incorporating essential narrative structures to provide solutions with the cultural and human dimension. This objective is broken down into four other specific objectives: (a) To identify the methodological-technological context of the sector; (b) To identify and characterise the factors that affect safety in construction; (c) To analyse the XR mechanisms to address them; (d) To propose a technological and functional framework for an extended reality (XR) solution for safety in construction and to demonstrate the proposed framework through implementation examples.As a result, it presents: (a) A methodological-technological reference framework for Construction 4.0 with some fifty associated technologies, components and challenges; (b) The identification, description and classification of a hundred factors that influence the safety of construction projects (fSCPs), as well as their link with precedents of XR experiences that consider them. It highlights the low integration with BIM and an arbitrary treatment to cover the needs given by the fSCPs; (c) a framework for the generation of extended reality solutions with the fundamentals for holistic construction safety management, considering the precedents in (a) and (b); (d) an analysis of the factors for the automation of VR experiences for construction safety; and (e) three examples of specific XR content developments on such a framework to evaluate and demonstrate their applicability.Keywords: Construction safety management, extended reality, virtual reality, augmented reality, mixed reality, Building information modelling, Construction 4.0, Storytelling.

Author: RENEDO MIRAMBELL, MARTÍ
Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
Programme: DOCTORAL DEGREE IN COMPUTING
Department: Department of Computer Science (CS)
Mode: Normal
Deposit date: 17/02/2023
Reading date: 28/03/2023
Reading time: 14:00
Reading place: FIB Sala d'actes Manuel Martí Recober B6-planta 0
Thesis director: ARRATIA QUESADA, ARGIMIRO ALEJANDRO
Committee:
     PRESIDENT: MAYORDOMO CÁMARA, ELVIRA
     SECRETARI: VELLIDO ALCACENA, ALFREDO
     VOCAL: LUGOSI, GABOR
Thesis abstract: This thesis presents a systematic approach to validate the results of clustering methods on weighted networks, particularly for the cases where the existence of a community structure is unknown. Including edge weights has many applications in network science, as there are many situations in which the strength of the connections between nodes is an essential property that describes the network. This evaluation of clustering methods comprises a set of criteria for assessing their significance and stability.First, a well-established set of community scoring functions, which already existed for unweighted graphs, has been extended to the case where the edges have associated weights. There is consideration given to how in some cases many possible weighted extensions to the same function can be defined, and each of them can suit different types of weighted networks.Additionally, methods to randomize graphs but maintaining the original graph¿s degree distribution have been defined in order to use these random graphs as baseline networks. This randomization together with the weighted community scoring functions are then used to evaluate cluster significance, since the random networks built from the original network with our methods provide reference values for each scoring function that will allow to actually determine whether a given cluster score for the original graph is better than a comparable graph with the same degree distribution but no community structure.As for the evaluation of stability, we define non parametric bootstrap methods with perturbations for weighted graphs where vertices are resampled multiple times, and the perturbations are applied to the edge weights. This, together with some fundamental similarity metrics for set partitions derived from information theory and combinatorics, constitutes our criteria for clustering stability. These criteria are based on the essential idea that meaningful clusters should capture an inherent structure in the data and not be overly sensitive to small or local variations, or the particularities of the clustering algorithm.A more in-depth study of the characteristics of cluster scoring functions and their potential bias towards clusters of a certain size has also been performed. This would render some of these functions unsuitable to compare results of clustering algorithms when the size of the partition differs considerably. For this analysis, we introduce parametrized multi-level ground truth models based on the stochastic block model and on preferential attachment that can showcase how the functions respond to varying the strength of each level of clusters in a hierarchical structure. Additionally, a scoring function that doesn't suffer from this kind of bias is proposed: the density ratio.This thesis also contributes with an efficient implementation of Newman's Reduced Mutual Information, a measure to compare set partitions based on information theory. Here it is used as a tool to compare network partitions, which is particularly useful for the evaluation of cluster stability, but it can have applications beyond the field of network clustering. Our algorithm uses an hybrid approach that combines analytical approximation with a Markov Chain Monte Carlo method for a good balance between accuracy and efficiency.Also an indispensable part of this thesis is the associated software that we developed, which includes the implementation of all the methods discussed in it. It all has all been included in our R package clustAnalytics. This package is designed to work together with igraph, the main R package dedicated to graphs, to make it easy and straightforward for other researchers to use. There are many useful applications for these tools: from the study and observation of new datasets, to the evaluation and benchmarking of clustering algorithms.