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Theses authorised for defence

DOCTORAL DEGREE IN AEROSPACE SCIENCE AND TECHNOLOGY

  • WANG, TENG: A Fast Engineering Approach to High Efficiency Power Amplifier Linearization for Avionics Applications.
    Author: WANG, TENG
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN AEROSPACE SCIENCE AND TECHNOLOGY
    Department: Department of Physics (FIS)
    Mode: Normal
    Deposit date: 06/11/2020
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: GILABERT PINAL, PERE LLUIS
    Committee:
         PRESIDENT: BARTZOUDIS, NIKOLAOS
         SECRETARI: GELONCH BOSCH, ANTONIO JOSE
         VOCAL: GARCÍA GARCÍA, JOSÉ ÁNGEL
    Thesis abstract: This PhD thesis provides a fast engineering approach to the design of digital predistortion (DPD) linearizers from several perspectives: i) enhancing the off-line training performance of open-loop DPD, ii) providing robustness and reducing the computational complexity of the parameters identification subsystem and, iii) importing machine learning techniques to favor the automatic tuning of power amplifiers (PAs) and DPD linearizers with several free-parameters to maximize power efficiency while meeting the linearity specifications. One of the essential parts of unmanned aerial vehicles (UAV) is the avionics, being the radio control one of the earliest avionics present in the UAV. Unlike the control signal, for transferring user data (such as images, video, etc.) real-time from the drone to the ground station, large transmission rates are required. The PA is a key element in the transmitter chain to guarantee the data transmission (video, photo, etc.) over a long range from the ground station. The more linear output power, the better the coverage or alternatively, with the same coverage, better SNR allows the use of high-order modulation schemes and thus higher transmission rates are achieved. In the context of UAV wireless communications, the power consumption, size and weight of the payload is of significant importance. Therefore, the PA design has to take into account the compromise among bandwidth, output power, linearity and power efficiency (very critical in battery-supplied devices). The PA can be designed to maximize its power efficiency or its linearity, but not both. Therefore, a way to deal with this inherent trade-off is to design high efficient amplification topologies and let the PA linearizers take care of the linearity requirements. Among the linearizers, DPD linearization is the preferred solution to both academia and industry, for its high flexibility and linearization performance. In order to save as many computational and power resources as possible, the implementation of an open-loop DPD results a very attractive solution for UAV applications. This thesis contributes to the PA linearization, especially on off-line training for open-loop DPD, by presenting two different methods for reducing the design and operating costs of an open-loop DPD, based on the analysis of the DPD function. The first method focuses on the input domain analysis, proposing mesh-selecting (MeS) methods to accurately select the proper samples for a computationally efficient DPD parameter estimation. Focusing in the MeS method with better performance, the memory I-Q MeS method is combined with feature extraction dimensionality reduction technique to allow a computational complexity reduction in the identification subsystem by a factor of 65, in comparison to using the classical QR-LS solver and consecutive samples selection. In addition, the memory I-Q MeS method has been proved to be of crucial interest when training artificial neural networks (ANN) for DPD purposes, by significantly reducing the ANN training time. The second method involves the use of machine learning techniques in the DPD design procedure to enlarge the capacity of the DPD algorithm when considering a high number of free parameters to tune. On the one hand, the adaLIPO global optimization algorithm is used to find the best parameter configuration of a generalized memory polynomial behavioral model for DPD. On the other hand, a methodology to conduct a global optimization search is proposed to find the optimum values of a set of key circuit and system level parameters, that properly combined with DPD linearization and crest factor reduction techniques, can exploit at best dual-input PAs in terms of maximizing power efficiency along wide bandwidths while being compliant with the linearity specifications. The advantages of these proposed techniques have been validated through experimental tests and the obtained results are analyzed and discussed along this thesis.

DOCTORAL DEGREE IN AGRI-FOOD TECHNOLOGY AND BIOTECHNOLOGY

  • RASAEIFAR, BAHAREH: Structure-Function Studies of Bombesin and Bradykinin Receptors and their Ligands for new Therapeutic Opportunities
    Author: RASAEIFAR, BAHAREH
    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: (DEAB)
    Mode: Normal
    Deposit date: 27/10/2020
    Reading date: 10/12/2020
    Reading time: 15:30
    Reading place: ETSEIB: videoconferència a l'enllaç videoconferència https://meet.google.com/onx-gfhu-vqj
    Thesis director: PEREZ GONZALEZ, JUAN JESUS
    Committee:
         PRESIDENT: ALKORTA OSORO, IBON
         SECRETARI: GARRIGA SOLE, PERE
         VOCAL: RICART PLA, JOSÉ MANUEL
    Thesis abstract: G-protein coupled receptors represents the largest family of membrane protein in eukaryotes cells with more than 800 members. The reason of their importance lies in their function, being responsible for the primary mechanism of signal transduction from the extracellular side to the cytosol of cells as well as responsible for controlling vesicle transport, ion channel, and enzyme activity. Defect in the GPCRs signal transduction process cause disorder in body organs such as cancer, color blindness, obesity, pain, depression, hyperthyroid adenoma, diabetes, schizophrenia. Hence, due to the important role they play in the body, they are target for 30% of the drugs in the market. The development of novel drugs targeting GPCRs highly depends on a solid structure-function relationships knowledge.Despite the variety of the GPCRs encoded in the human genome, they exhibit the same architecture however they represent a large variation in the structure. Also, despite efforts carried out to determine the crystal structures of the G-PCRs, still, there are numerous challenges of for crystallization of them. Despite the publication of a number of crystallographic structures in the last years, there are many GPCrs which structure is not determined. Homology modeling is a method that can help to study both the structure and function of the GPCRs and it can provide more information when the process continues to the virtual screening. Homology modeling with the help of molecular dynamics simulation can discover the dynamic behavior of GPCRs by the means of discovering their conformational change. This method is an economic method for discovering novel drugs as well as explaining their structure-activity relationship and pharmacology in the step before experimental methods. In the present study, we constructed an 3Dstructure of six GPCRs, including M3 muscarinic receptor, bradykinin B1 receptor, Bradykinin B2 receptor, neuromedin receptor(BB1R), Gastrin-releasing peptide receptor (BB2R), and bombesin receptor subtype 3(BB3R). Models were constructed using the closest the closest structure available in the phylogenetic tree as template. In regard to M3 muscarinic, the aim of the study was the evaluation of structure refinement using molecular dynamics and the effect of the template selection, presence of a ligand in the refinement process on the accuracy of the models constructed. In regards to the bradykinin receptor, the models of bradykinin B1 receptor and bradykinin B2 receptors were constructed in a previous study of the group. Then, pharmacophore definition was done and subsequent virtual screening led to the discovery of some novel small molecules with antagonist activity. In the present study, the pharmacophore of the two receptors was compared to understand specific molecular features of the small molecules bradykinin ligands that make them selective for each one of these receptors. Finally, for discovering the novel chemical scaffolds for the three bombesin receptors the models of each subtype of the bombesin receptor were constructed from neurotensin receptor (NTS1), and the refinement of 500 ns was performed for each one of the models. The results of the present study show that in the refinement process, the closer the template is to the target receptor and the use of a ligand in the refinement process can lead to model accurate models. Also, the selectivity of the small molecules bradykinin receptors was identified properly by comparison of the pharmacophores of two receptors . Finally, the study of the features of bombesin receptors led to the discovery of novel small molecules with antagonist activity for BB1R and important residues of BB2R and BB3R for further mutagenesis study.

DOCTORAL DEGREE IN ARCHITECTURAL DESIGN

  • BELTRAN BORRÀS, JÚLIA: Una visió històrica com a eina projectual: el cas de Morella
    Author: BELTRAN BORRÀS, JÚLIA
    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 DESIGN
    Department: Department of Architectural Design (PA)
    Mode: Normal
    Deposit date: 15/10/2020
    Reading date: 11/12/2020
    Reading time: 16:00
    Reading place: Sala de Graus ETSAB - UPC Campus Sud - Av Diagonal 649 - videoconferència: meet.google.com/sem-zyty-vph
    Thesis director: SAURA CARULLA, MAGDALENA
    Committee:
         PRESIDENT: FERRER FORES, JAIME JOSE
         SECRETARI: CARABI BESCOS, GUILLEM
         VOCAL: BAGNATO, VINCENZO PAOLO
         VOCAL: RIPOLL MASFERRER, RAMON
         VOCAL NO PRESENCIAL: TORRES PAREDES, EDGAR ALBERTO
    Thesis abstract: How and why is history useful to the architect in today¿s world? The research focused on the role of designers in bringing back the historical precedents to bear on the present practice, and furthermore presented a synthesis of the theories and approaches on the matter in the last decades. The main objective is to elaborate a useful methodology to understand the urban form, the buildings and the public space at present, looking back to understand the meaning of things, and to illustrate that throughout different periods of time, history had been a design tool which allowed the architect to encounter the balance between permanence and change when modifying a site and offering users a new place where memories and hope could converge. In order to explore the link between the project and the history, the architecture of Morella, in Spain, was analysed through pictures, historical drawings, plans, ethnographic reports, and in the current and ancient cartography. Furthermore, dialogic studies, urban morphology, space syntax and direct observation in the city were used as part of the methodology. The result is a longitudinal study about Morella as the main case study in which the morphological configurative studies, the design poetic act and, finally, the social use of space converged. In conclusion, the methodology used proved to be extremely useful to elaborate a new architectural interpretation of Morella, and to explain how and why the city took the shape it currently has.

DOCTORAL DEGREE IN ARCHITECTURAL, BUILDING CONSTRUCTION AND URBANISM TECHNOLOGY

  • PESIC, NIKOLA: Geo-climatic potential for advanced natural ventilation comfort cooling approach in mid-rise office buildings in the north-western Mediterranean
    Author: PESIC, NIKOLA
    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: 22/10/2020
    Reading date: 17/12/2020
    Reading time: 10:30
    Reading place: ETSAB (Per videoconferència-COVID 19) - UPC Campus Sud - Av Diagonal 649 - videoconferència: meet.google.com/gag-gtii-amc
    Thesis director: MUROS ALCOJOR, ADRIAN | ROSET CALZADA, JAIME
    Committee:
         PRESIDENT: ZAMORA MESTRE, JOAN LLUIS
         SECRETARI: NOVLJAN, TOMAZ
         VOCAL NO PRESENCIAL: WADEL RAINA, GERARDO FABIAN
         VOCAL NO PRESENCIAL: ACHA ROMÁN, CONSOLACIÓN ANA
    Thesis abstract: The objective of this investigation is to evaluate the geo-climatic potential for comfort cooling energy savings in mid-rise office buildings applying advanced natural ventilation (ANV) approach based on the stack-effect. The region of interest is the Mediterranean coastline of Catalonia with selected reference geographical locations¿the cities of Barcelona, Terrassa and Tarragona. In the first part of this research is evaluated the climatic potential for natural ventilation (CPNV) for each location, as a theoretical level of availability of natural ventilation (NV) based on the model of adaptive thermal comfort. For a comparison of geo-climatic potentials in a wider regional context, additional reference locations are chosen along the Northern Mediterranean: Valencia, Marseille, Rome, Koper, Split, Athens and Nicosia. Generated results confirm that NV is feasible mainly from April to October while in July and August is considerably limited due to unfavourable climate conditions. The second part of the work examines cooling energy savings of the hypothetical mid-rise office-type building model ¿A¿. Applied building performance simulations (BPS) demonstrates achieved total yearly cooling energy savings in the region of Catalonia between 22% and 51%. The same model positioned along the Northern Mediterranean displays cutting in yearly cooling energy loads in a wider range¿from 6% to 51%.The following section evaluates levels of climate change vulnerability applying climate scenarios for the selected time-slices¿the years 2050 and 2080. It is indicated that the potential of ANV will be reduced close to zero in July and August in 2080. However, the introduction of selected assisted cooling techniques demonstrates that this impact can be absorbed approximately back to the previously evaluated scale in the horizon of 2050. In the last part of the investigation, the new defined building model ¿B¿ displays an improvement of comfort cooling energy efficiency: selected NV techniques are merged in order to take advantage of lower nocturnal outdoor temperatures by passive means, whose potential is reflected on the decrease of active day-time cooling loads. For this purpose, the positioned model in Barcelona achieves the yearly reduction of cooling energy loads by 65% in present-time weather conditions. At the conclusion, under projected climate configurations for 2050 and 2080, in Barcelona Terrassa and Tarragona, the series of BPS displays a higher level of climate resilience and the overall reduction of cooling energy loads within 53% and 59%.The key-contribution and the novelty of this research is in the performed series of experimental BPS of the building model ¿A¿ where are detected ANV system¿s weaknesses as a result of estimated unfavourable climate effects. Relative to observed limited cooling performances, ANV is shifted from an autonomous comfort cooling concept to being a part of a complex ventilative system with specific day- and night-time cycles. Such a new established design approach based on dynamic heat storage is associated with an introduction of lower nocturnal and early morning outdoor air temperatures, as being less affected with future regional climate change. An achieved advantageous momentum in energy performances is categorized through strengths and opportunities. Thereby, the building model ¿B¿, the outcome of this investigation, represents the climate responsive building form with an integrated climate sensitive comfort cooling system, which delivers a higher level of energy efficiency¿seen as an acquired factor of resilience towards estimated climate change threats. Such a conceptualised hypothetical building prototype may prove to be a beneficial contributor in the current process of rapid deployment of renewable energy sources in the regional building sector, observed as well from the perspective of the ongoing European Union¿s energy transition.

DOCTORAL DEGREE IN ARCHITECTURAL, CIVIL AND URBAN HERITAGE AND REFURBISHMENT OF EXISTING BUILDINGS

  • VÉLEZ RESTREPO, MARÍA ISABEL: El museo de arte como Obra Arquitectónica y Artística
    Author: VÉLEZ RESTREPO, MARÍA ISABEL
    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, CIVIL AND URBAN HERITAGE AND REFURBISHMENT OF EXISTING BUILDINGS
    Department: (RA)
    Mode: Normal
    Deposit date: 21/10/2020
    Reading date: 17/12/2020
    Reading time: 16:00
    Reading place: ETSAB (Per videoconferència-COVID 19) - UPC Campus Sud - enllaç: meet.google.com/ido-ezhp-vba
    Thesis director: ESCODA PASTOR, MARIA CARMEN | ZARAGOZA DE PEDRO, MARIA ISABEL
    Committee:
         PRESIDENT: MIOTTO BRUSCATO, UNDERLEA
         SECRETARI: ESQUINAS DESSY, JESÚS
         VOCAL NO PRESENCIAL: ARÉVALO RODRÍGUEZ, FEDERICO MANUEL
    Thesis abstract: The topic of this investigation is focused in the study of the transformations and relationships of the Art Museum being both an artistic work of art and an architectural work. The concept of ¿work¿ is the result of a thought process that transverse both disciplines (art and architecture). Both disciplines have help to build the ideological and material substance of it by defining it from not only a diverse point of view, with parallel temporalities but also migrating knowledge transversely between them, building the Art Museum as an artistic work.The Art Museum will remain present having as speakers both artists and architects that along with other disciplines will build its existence with a diverse and ¿participative¿ agenda due that its presence in the current time is not only a physical existence, but it also has other materialization without the actual building. Other existences of it will be developed and established will be possible thanks to the multiples forms of the art museum.The Art Museum is an idea that can take multiple shapes; constructed, liveable, indecipherable or indivisible. Other realities will be possible by the multiple looks of it.

DOCTORAL DEGREE IN ARCHITECTURE, ENERGY AND ENVIRONMENT

  • LÓPEZ ORDÓÑEZ, CARLOS FERNANDO: Planificación urbana en ciudades dispersas de clima desértico: la densificación vertical como estrategia para la mejora ambiental. El caso de Hermosillo (México)
    Author: LÓPEZ ORDÓÑEZ, CARLOS FERNANDO
    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 ARCHITECTURE, ENERGY AND ENVIRONMENT
    Department: Department of Architectural Technology (TA)
    Mode: Normal
    Deposit date: 06/11/2020
    Reading date: 30/11/2020
    Reading time: 16:30
    Reading place: Sala de Graus ETSAB - UPC Campus Sud - Av Diagonal 649 - videoconferència: meet.google.com/zwu-tdbo-fko
    Thesis director: CRESPO CABILLO, ISABEL | ROSET CALZADA, JAIME
    Committee:
         PRESIDENT: OCHOA DE LA TORRE, JOSÉ MANUEL
         SECRETARI: ALONSO MONTOLÍO, CARLOS
         VOCAL NO PRESENCIAL: MORGANTI, MICHELE
    Thesis abstract: By 2050, the world's population will have doubled and will be mainly urban. This perspective generates the need to think about the present and the future of cities, especially those located in mid-latitudes, where a large part of that population accumulates. Many of these cities are in regions with hot semi-arid and hot-dry climates.Traditionally, desert cities were designed in compact shapes in response to various climatic factors. Today, these cities have adopted the dispersed city model, driven by car use, the emergence of cooling systems, and a steady decline in energy costs. This form of growth raises a series of problems from an environmental point of view: poor habitability of the public space, long distances, an elevated land use, high demand for cooling.The goal of this thesis is to evaluate the energy repercussions of the increase in urban density in dispersed and low-density cities with a hot-dry climate in the northwestern region of Mexico. The city of Hermosillo in Sonora, a medium-sized city in expansion, is taken as a case study. This thesis analyzes the effects of urban densification on three different scales: city, neighborhood, and building.Based on a city-scale cartographic analysis, this thesis shows that Hermosillo presents a dispersed pattern of low-density growth with two main characteristics: low centrality and high fragmentation. The low centrality is due to the loss of population and economic weight of the urban center in favor of the periphery. The urban fragmentation is a result of the existence of a large number of vacant lots (35% of the urban area). Therefore, two urban strategies are identified and could be followed to slow down the growth of the urban area: the infill of vacant lots and the densification of existing fabrics (stacking) for the creation of high-density sub-centers.The historic center of Hermosillo is selected to carry out the analysis on a neighborhood scale. The impact that a densification process of an existing urban fabric has on the habitability of the urban space is assessed. Currently, this fabric has a high pedestrian potential, but low population and building density, and high levels of solar radiation. In this thesis, the study area is rethought through a densification process employing the mixed-use lot and the stacking of houses. It is shown that by following the current regulations is possible to achieve building density values similar to those of urban centers and tissue of cities with compact morphology. Also, by allowing an increase in density allows achieving streets with an aspect ratio of around h/w= 1, a ratio that, at this latitude, permits the creation of "shadow corridors" spaces protected from radiation.Finally, the impact of stacking on energy performance at the building scale is analyzed using dynamic thermal simulations. To this end, this thesis compares the thermal behavior of free-running homes and the energy demand for cooling during the hot season of isolated single-family homes and multi-family homes in height. The conclusion is that the higher the stacking level, the better the thermal and energy performance. Furthermore, this study demonstrates that in homes without refrigeration, the use of solar protection on windows achieves a slightly superior improvement than that of thermal insulation.Therefore, this thesis allows us to demonstrate that an increase in density (building and population) has advantages at different scales, especially in cities with a hot-desert climate. Stacking allows the creation of shade in the public space and, at the same time, an improvement in the internal energy consumption of refrigerated homes.

DOCTORAL DEGREE IN BUSINESS ADMINISTRATION AND MANAGEMENT

  • LLINAS SALA, DANIEL: La consolidación de las prácticas de alto rendimiento de gestión de personas, una tarea prioritaria para el éxito de los sistemas de producción cíber-físicos en las medianas empresas españolas
    Author: LLINAS SALA, DANIEL
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN BUSINESS ADMINISTRATION AND MANAGEMENT
    Department: Department of Management (OE)
    Mode: Normal
    Deposit date: 28/10/2020
    Reading date: 03/12/2020
    Reading time: 16:00
    Reading place: ETSEIB: Videoconferència per COVID-19: https://meet.google.com/hkw-vnge-osy
    Thesis director: COLL BERTRAN, JOSEP | ABAD PUENTE, JESUS
    Committee:
         PRESIDENT: RUBIO ROMERO, JUAN CARLOS
         SECRETARI: SALLAN LEYES, JOSE MARIA
         VOCAL: VAILLANT, YANCY
    Thesis abstract: Experts agree that cyber-physical production systems (CPPS), commonly known as lndustry 4.0 (14.0), have the potential to transform the business landscape through significant improvements in productivity. Those improvements come not only from process efficiency but, specially, from new business models. lmportant for this transformation potential is the fact that those improvements will be on top of the existing, significant, productivity differences between companies, which can make the gap between the leaders and followers potentially unbridgeable.This thesis shows that, in order to successfully cope with this digital disruption, medium-sized firms have to undertake, as a priority, the consolidation of high-performance people management practices. lt also brings evidence that, in the context of CPPS, time is a competitive variable more relevant than ever. Due to the special importance of accumulated learning in digitalization, there are not only very important advantages of being first but, companies that may consider 14.0 as a choice and not an imperative and, in consequence, may postpone its development, risk being left behind.Likewise, and to emphasize this sense of urgency, this thesis shows that the complexity associated with the implementation of 14.0 is high and that the process of doing so can properly be described as a "cultural transformation". Consequently, being a cultural transformation, a fact that inevitably requires time, and knowing that the process of consolidation of high-performance practices also requires time, it becomes an ever more important competitive variable. The urgency for medium-sized companies to start this journey cannot be over emphasized.From the perspective of the level of consolidation of those practices, Spanish medium-sized companies have, in general, a significant deficit, when compared to those of a good part of the OECD countries, usually their most direct competitors. In addition, they also have lower levels of digitization, making the challenge even bigger. This does not mean that there are not medium-sized companies with those high-performance practices consolidated or high levels of digitization but, in general, the average is low and dispersion high.The most relevant challenge of 14.0 does not come from the technological elements intrinsic to this digital disruption, but from the need to innovate in business processes. lt is not intended here to state that technology does not play an important role in lndustry 4.0, it does, but that technological complexity should not hide the fact that it is only a tool, a means toan end. This thesis is structured as follows:a) First, it is shown that there is an agreement in the fact that the expected impact of CPPS on productivity is not only very important, but transformative, disruptive.b) Second, by digging into what happened in other technological innovations that have had a transformative impact in the past, such as the alternate current motor and the information and communication technologies, it is shown that in both cases, there is agreement that their impact on productivity has materialized through innovation in processes and business models.c) Third, evidence is presented that for CPPS, the impact may be even bigger, because digitization seems to create a growing gap over time between winners and followers, generating a kind of virtuous cycle.d) Fourth, it is shown that there is consensus behind the cause of the wide dispersion of productivity and innovation levels: the dispersion in the level of implementation of high-performance people management practices.e) Fifth, evidence is presented that Spanish medium-sized firms are lagging behind in the level of implementation of high-performance people management practices as well as in digitization, when compared with those of the OECD countries. f) Finally, the proposals to be validated, the selected methodology, the results and conclusions are presented.

DOCTORAL DEGREE IN CIVIL ENGINEERING

  • ORTEGA GELABERT, OLGA: Advanced numerical techniques for inverse problems in geophysics
    Author: ORTEGA GELABERT, OLGA
    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: Normal
    Deposit date: 04/11/2020
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: ZLOTNIK MARTINEZ, SERGIO | DIEZ MEJIA, PEDRO
    Committee:
         PRESIDENT: LEDO FERNÁNDEZ, JUAN JOSÉ
         SECRETARI: GARCIA GONZALEZ, ALBERTO
         VOCAL: FULLEA URCHULUTEGUI, JAVIER
    Thesis abstract: This thesis presents an efficient methodology to couple Model Order Reduction techniques within the framework of geophysical probabilistic inversion problems. Accurate models of the interaction between Earth inner processes and surface features are essential to make reliable predictions of the observables which are a fundamental part of Bayesian inference. Markov Chain Monte Carlo (MCMC) methods have become standard in dealing with probabilistic inversions and they rely on sampling strategies that require solving forward problems many times. Computationally expensive large-scale forward problems are the principal bottleneck that can limit the capabilities and potential of multi-observable geophysical probabilistic inversions. In particular, dynamical effects arising from the sub-lithospheric mantle flow are not usually taken into account in the estimation of surface elevation due to the high computational cost of the associated 3D Stokes flow problem. The main idea of this thesis is to use the Reduced Basis (RB) method as a surrogate of the true forward problem (3D Stokes flow) to provide fast and accurate approximations. The surrogate is then used to generate samples of the posterior distribution at a much lower computational cost. RB strategies are based on expressing the solution of a problem in a low dimensional space, i.e. a reduced basis. Taking advantage of the convergence nature of the MCMC, we propose a greedy strategy that builds the reduced basis on the fly and as required by the inverse problem. In doing so, the basis is specifically tailored to the posterior features of the problem. In addition, to guarantee an accurate surrogate we define a goal-oriented error estimator which focuses on a particular Quantity of Interest of the problem and, therefore, it guides the basis to achieve the required accuracy in such particular features. All this translates into a problem-shaped basis that is more compact and smaller than if it had to be accurate everywhere in the domain. Moreover, to deal with the costly assembly of matrices, we use the specific parametrization of the problem and sampling strategy to define an assembly procedure that efficiently updates the matrices only with the contribution of the elements that changed between successive inversion steps.The benefits and limitations of the method are illustrated through several numerical examples. Finally, to demonstrate the applicability of the method two more realistic inverse problems are presented. The first one uses dynamic topography to infer the Lithosphere-Asthenosphere Boundary depth of a spherical domain representing a portion of Earth and the second one is applied to a larger problem in which the African lithospheric structure is discretized in 1225 inversion parameters.

DOCTORAL DEGREE IN COMPUTATIONAL AND APPLIED PHYSICS

  • CALMET, HADRIEN: Large-scale CFD and micro-particles simulations in a large human airways under sniff condition and drug delivery application.
    Author: CALMET, HADRIEN
    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: 08/10/2020
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: HOUZEAUX, GUILLAUME PASCAL
    Committee:
         PRESIDENT: SOUDAH PRIETO, EDUARDO
         SECRETARI: FERNANDEZ TENA, ANA
         VOCAL: ALOBID, ISAM
    Thesis abstract: As we inhale, the air drawn through our nose undergoes successive accelerations and decelerations as it is turned, split, and recombined before splitting again at the end of the trachea as it enters the bronchi. Fully describing the dynamic behaviour of the airflow and how it transports inhaled particles poses a severe challenge to computational simulations. The dynamics of unsteady flow in the human large airways during a rapid and short inhalation (a so-called sniff) is a perfect example of perhaps the most complex and violent human inhalation inflow. Combining the flow solution with a Lagrangian computation reveals the effects of flow behaviour and airway geometry on the deposition of inhaled microparticles.Highly detailed large-scale computational fluid dynamics allow resolving all the spatial and temporal scales of the flow, thanks to the use of massive computational resources. A highly parallel finite element code running on supercomputers can solve the transient incompressible Navier-Stokes equations on unstructured meshes. Given that the finest mesh contained 350 million elements, the study sets a precedent for large-scale simulations of the respiratory system, proposing an analysis strategy for mean flow, fluctuations, wall shear stresses, energy spectral and particle deposition on a rapid and short inhalation.Then in a second time, we will propose a drug delivery study of nasal sprayed particle from commercial product in a human nasal cavity under different inhalation conditions; sniffing, constant flow rate and breath-hold. Particles were introduced into the flow field with initial spray conditions, including spray cone angle, insertion angle, and initial velocity. Since nasal spray atomizer design determines the particle conditions, fifteen particle size distributions were used,each defined by a log-normal distribution with a different volume mean diameter.This thesis indicates the potential of large-scale simulations to further understanding of airway physiological mechanics, which is essential to guide clinical diagnosis; better understanding of the flow and delivery of therapeutic aerosols, which could be applied to improve diagnosis and treatment.
  • GAWALI, SANDEEP BABU: Intracavity spatial filtering in broad area semiconductor laser.
    Author: GAWALI, SANDEEP BABU
    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 Statistics and Operations Research (EIO)
    Mode: Normal
    Deposit date: 06/11/2020
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: TRULL SILVESTRE, JOSE FRANCISCO | STALIUNAS, KESTUTIS
    Committee:
         PRESIDENT: VILASECA ALAVEDRA, RAMON
         SECRETARI: ESTEBAN MARTIN, ADOLFO
         VOCAL: PEREGO, AURO
    Thesis abstract: Semiconductor lasers in high-power regime typically manifest a poor beam quality due to its asymmetric beam divergence and its large beam quality factor (M2). The emission along one of the transverse directions (slow axis) is typically multimode while being single mode in the perpendicular direction (fast axis). Due to the multimode emission and the absence of any intrinsic mode selection mechanism, the beam quality of broad area semiconductor (BAS) laser is degraded. In this work, we demonstrate that, by means of spatial filtering technique, the beam quality may be improved along the lateral direction (slow axis). For the filtering purpose, we propose the use of photonic crystal (PhC) as the spatial filtering element. The PhC offers an advantage in terms of its compact size, which allows miniaturization of the device. The successful implementation of this scheme could lead to monolithic integration, with the PhC directly integrated between the front facet of the semiconductor material and the laser cavity mirror. The PhCs were fabricated on N-BK7 glass substrate using tightly focused femtosecond Bessel beam. Two different PhC with different parameters were used in the experiment. The filtering of the PhC appears due to the deflection of selected components of the beam out of the propagation direction, using the Laue configuration.Since the PhC operates only in the near field plane, the access to this plane for the experimental testing of the idea introduces a technological difficulty in such small devices.We followed a simplified approach using an extended cavity configuration, which mimics the action of the compact cavity. The advantage of the extended cavity setup is that it allows testingdifferent filtering geometries in the same setup. The extended cavity was built using AR coated single emitter BAS laser, fast axis collimator, a double 4f lens system, and an external mirror with reflectivity of 4%. This extended cavity allows implementing two different techniques, i.e. an intracavity slit and a photonic crystal in the same setup. The cavity was characterized by measuring the output power, beam quality factor (M2), spectrum, and near/far field laser profiles. Before testing the action of PhC, we tested the conventional spatial filtering using intracavity slit placed in the far field and acting on the beam in the lateral direction by blocking the higher angular components of the beam. The output beam from the external cavity was characterized by measuring the M2 along the slow axis and calculating the brightness of the beam. We demonstrate an enhancement in the brightness by factor of two compared to the unfiltered beam situation. We further evaluated the effect of the reflectivity of the feedback mirror on the output power and spatial profile of the beam. The filtering action of the PhCs was characterized using the same extended cavity configuration. In this configuration an enhancement of the brightness by a factor between 1.3 and 1.5 was demonstrated for the different crystals. In addition, we used another emitter with longer cavity length and transverse width and with 4 % coating on the front facets. The experimental results obtained using intracavity slit and PhC were compared with the numerical results obtained froma numerical model of broad area laser created to simulate the action of spatial filtering using either the intracavity slit or the PhC. Both results showed a good agreement between the experiments and the numerical results.The numerical code was used to further optimize the brightness enhancement by simulating different filtering geometries.

DOCTORAL DEGREE IN COMPUTER ARCHITECTURE

  • DIMIC, VLADIMIR: Runtime-assisted optimizations in the on-chip memory hierarchy
    Author: DIMIC, VLADIMIR
    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: (DAC)
    Mode: Normal
    Deposit date: 15/09/2020
    Reading date: 27/11/2020
    Reading time: 09:30
    Reading place: ETSETB C6-E101: Defensa per videoconferència COVID19- https://zoom.us/j/91011374678?pwd=SFlubjlsQ2szeDVTc09UUUJRNlpBZz09
    Thesis director: MORETÓ PLANAS, MIQUEL | CASAS GUIX, MARC
    Committee:
         PRESIDENT: NIKOLERIS, NIKOS
         SECRETARI: RADOJKOVIC, PETAR
         VOCAL: BEIVIDE PALACIO, JULIO RAMON
    Thesis abstract: Following Moore's Law, the number of transistors on chip has been increasing exponentially, which has led to the increasing complexity of modern processors. As a result, the efficient programming of such systems has become more difficult. Many programming models have been developed to answer this issue. Of particular interest are task-based programming models that employ simple annotations to define parallel work in an application. The information available at the level of the runtime systems associated with these programming models offers great potential for improving hardware design. Moreover, due to technological limitations, Moore's Law is predicted to eventually come to an end, so novel paradigms are necessary to maintain the current performance improvement trends.The main goal of this thesis is to exploit the knowledge about a parallel application available at the runtime system level to improve the design of the on-chip memory hierarchy. The coupling of the runtime system and the microprocessor enables a better hardware design without hurting the programmability.The first contribution is a set of insertion policies for shared last-level caches that exploit information about tasks and task data dependencies. The intuition behind this proposal revolves around the observation that parallel threads exhibit different memory access patterns. Even within the same thread, accesses to different variables often follow distinct patterns. The proposed policies insert cache lines into different logical positions depending on the dependency type and task type to which the corresponding memory request belongs.The second proposal optimizes the execution of reductions, defined as a programming pattern that combines input data to form the resulting reduction variable. This is achieved with a runtime-assisted technique for performing reductions in the processor's cache hierarchy. The proposal's goal is to be a universally applicable solution regardless of the reduction variable type, size and access pattern. On the software level, the programming model is extended to let a programmer specify the reduction variables for tasks, as well as the desired cache level where a certain reduction will be performed. The source-to-source compiler and the runtime system are extended to translate and forward this information to the underlying hardware. On the hardware level, private and shared caches are equipped with functional units and the accompanying logic to perform reductions at the cache level. This design avoids unnecessary data movements to the core and back as the data is operated at the place where it resides.The third contribution is a runtime-assisted prioritization scheme for memory requests inside the on-chip memory hierarchy. The proposal is based on the notion of a critical path in the context of parallel codes and a known fact that accelerating critical tasks reduces the execution time of the whole application. In the context of this work, task criticality is observed at a level of a task type as it enables simple annotation by the programmer. The acceleration of critical tasks is achieved by the prioritization of corresponding memory requests in the microprocessor.
  • TRILLA RODRIGUEZ, DAVID: Non-functional considerations of time-randomized processor architectures
    Author: TRILLA RODRIGUEZ, DAVID
    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: (DAC)
    Mode: Normal
    Deposit date: 14/10/2020
    Reading date: 04/12/2020
    Reading time: 16:00
    Reading place: Sala C6-E106 (Departament Arquitectura de Computadors - DAC) - videoconferència ( https://zoom.us/j/97951531254 )
    Thesis director: ABELLA FERRER, JAIME | HERNANDEZ LUZ, CARLES
    Committee:
         PRESIDENT: DI CARLO, STEFANO
         SECRETARI: UNSAL, OSMAN SABRI
         VOCAL NO PRESENCIAL: VEGA, AUGUSTO JAVIER
    Thesis abstract: Critical Real-Time Embedded Systems (CRTES) are the subset of embedded systems with timing constraints whose miss behavior can endanger human lives or expensive equipment. To provide evidence of correctness, CRTES are designed, implemented and deployed in adherence to safety standards and certification regulations. To that end, CRTES follow strict Validation & Verification (V&V) procedures of their functional and non-functional properties. One of the most important non-functional properties is timing, which builds on computing the worst-case execution time of tasks and a schedule of tasks so that the overall system timing behavior is correct. However, the use of more complex hardware and software to satisfy CRTES unprecedented performance requirements, heavily increase the cost of V&V. For timing V&V, statistical techniques, like Measurement-Based Probabilistic Timing Analysis (MBPTA) help to address the complexity of hardware and software in CRTES. To that end, they benefit from randomization of temporal behavior at the hardware level. In this line, Time-Randomized Processors (TRP) contain timing V&V costs by breaking systematic pathological behaviors and enabling MBPTA applicability. In the context of TRP, this thesis shows that hardware and software designs incorporating randomization can not only successfully tackle the existing timing analysis problem, but also provide helpful properties to other emerging non-functional metrics key in CRTES like reliability, security and energy. For reliability, we show that TRP are naturally resilient against hardware aging effects and voltage noise and we add up to such resilience by improving its design. Also, TRP hinders security threats and intrusions by breaking and mangling the deterministic association between memory mapping and access time and we develop a framework for secure automotive operation. Finally for energy, we introduce a taxonomy to guide the future challenges for worst-case energy estimation and make the first steps towards the use of MBPTA-like methodology to address worst-case energy estimation under the presence of process variation. Moreover this thesis also shows that together with the application of MBPTA-like methodology, TRP also naturally expose and break pathological energy consumption patterns and help in validating and accounting instantaneous peak power demands. In summary, this thesis pioneers several aspects of the use of TRP to address the emerging challenges that CRTES face in the reliability, security and energy domains.

DOCTORAL DEGREE IN CONSTRUCTION ENGINEERING

  • EMADI, SEYYEDBEHRAD: Application of observability techniques to structural system identification including shear effects,
    Author: EMADI, SEYYEDBEHRAD
    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 CONSTRUCTION ENGINEERING
    Department: (DECA)
    Mode: Normal
    Deposit date: 30/10/2020
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: TURMO CODERQUE, JOSE | LOZANO GALANT, JOSE ANTONIO
    Committee:
         PRESIDENT: CASAS RIUS, JUAN RAMON
         SECRETARI: ORTIZ LOZANO, JOSÉ ANGEL
         VOCAL: YUAN, SUN
    Thesis abstract: EmadiAccording to Timoshenko¿s beam theory, nodal rotations in beam-like structures are produced by bending and shear effects. On the one hand, bending rotations can be easily calculated by the Euler-Bernoulli stiffness matrix method. On the other hand, shear rotations are traditionally neglected as their effects are practically negligible in most structures. In addition, calculating the shear rotation effects by the stiffness matrix method is not straight forward tasks and it presents practical limitations. Nevertheless, this assumption might lead to significant errors in the simulation of the structural response of some structures (such as deep beams and composite structures). The shear effects are also neglected in the inverse analysis of structures (Structural System Identification) used to calibrate the mechanical properties of the structural elements from the monitoring on-site. Recently, one of the first methods for the inverse analysis of structures including the shear effects (the Observability Method, OM) was presented. This method introduced Timoshenko¿s beam theory into the Stiffness Matrix Method (SMM). In this way, the vertical deflections produced by shear effects were included into the simulation while the shear rotations were neglected. In this method, the mechanical properties of the structures could be obtained from the nodal deflections measured on static tests on site. One of the main controversial features of this procedure is the fact that the measurement set must include rotations. This characteristic might be especially problematic in those structures where rotations due to shear are not negligible. In fact, in this case, neglecting the shear rotations might lead to significant errors. This simplification might be especially problematic in those structures where only rotations can be measured. In addition to the OM, some other inverse analysis methods including shear deformation effects have been recently presented in the literature. Nevertheless, all these methods also fail to deal with the shear rotation effects, as they only take into account in the system of equations the vertical deflections produced by shear. Therefore, when actual rotations on site are used estimations with significant errors can be obtained. To fill these gaps, this Ph.D. Thesis deals with the analysis of the effects of the shear deformations in beam-like structures from a direct and inverse approach. First of all, the SMM is updated to enable the calculation of the shear rotations from a direct analysis. This method is used to evaluate the effects of the shear rotations in beam-like structures with different slenderness ratios. In addition, for the first time in the literature, the slenderness ratios where the shear rotation effects can be neglected from a direct analysis are identified. Secondly, the OM is updated to enable the inverse analysis of structures with shear effects from measurement sets with only vertical deflections. This modification is based on the introduction of a numerical optimization method. With this aim, the inverse analysis of several examples of growing complexity are presented to illustrate the validity and potential of the updated method. Finally, the OM is modified to enable the inverse analysis from shear rotations. This modification is based on the introduction of a new iterative process to estimate successively the values of the shear rotations. To illustrate the applicability and potential of the proposed method, the inverse analysis of several examples of growing complexity is presented. A set of calculation recommendations and future researches are also proposed.

DOCTORAL DEGREE IN ELECTRONIC ENGINEERING

  • MATEU MATEUS, MARC: A contribution to unobtrusive video-based measurement of respiratory signals.
    Author: MATEU MATEUS, MARC
    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: 21/10/2020
    Reading date: 01/12/2020
    Reading time: 10:00
    Reading place: ETSEB: aula de teleensenyament del B3. VIDEOCONFERÈNCIA PER covid-19 https://meet.google.com/qjg-qmzv-zxe
    Thesis director: RAMOS CASTRO, JUAN JOSE | FERNANDEZ CHIMENO, MIREYA
    Committee:
         PRESIDENT: VIDAL MARTÍNEZ, MARIA NIEVES
         SECRETARI: ALONSO LÓPEZ, JOAN FRANCESC
         VOCAL: JAUREGUI TELLERIA, RICARDO IGNACIO
    Thesis abstract: Due to the growing popularity of video-based methods for physiological signal measurement, and taking into account the technological advancements of these type of devices, this work proposes a series of new novel methods to obtain the respiratory signal from a distance, based on video analysis. This thesis aims to improve the state of the art video methods for respiratory measurement, more specifically, by presenting methods that can be used to obtain respiratory variability or perform respiratory rhythm measurements. Moreover, this thesis also aims to present a new implementation of a time-frequency signal processing technique, to improve its computational efficiency when applied to the respiratory signals.In this document a first approach to video-based methods for respiratory signal measurement is performed, to assert the feasibility of using a consumer-grade camera, not only to measure the mean respiratory rate or frequency, but to assert if this hardware could be used to acquire the raw respiratory signal and the respiratory rhythm as well. In this regard a new video-based method was introduced that measures the respiratory signal of a subject at a distance, with the aid of a custom pattern placed on the thorax of the subject.Given the results from the first video-based method, a more broad approach was taken by comparing three different types of video hardware, with the aim to characterise if they could be used for respiratory signal acquisition and respiratory variability measurements. The comparative analysis was performed in terms of instantaneous frequency, as it allowed to characterise the methods in terms of respiratory variability and to compare them in the same terms with the reference method.Subsequently, and due to the previous obtained results, a new method was proposed using a stereo depth camera with the aim to tackle the limitations of the previous study. The proposed method uses an hybrid architecture were the synchronized infrared frame and depth point-cloud from the same camera are acquired. The infrared frame is used to detect the movements of the subject inside the scene, and to recompute on demand a region of interest to obtain the respiratory signal from the depth point-cloud. Furthermore, in this study an opportunistic approach is taken in order to process all the obtained data, as it is also the aim of this study to verify if using a more realistic approach to respiratory signal analysis in real-life conditions, would influence the respiratory rhythm measurement. Even though the depth camera method proved reliable in terms of respiratory rhythm measurement, the opportunistic approach relied on visual inspection of the obtained respiratory signal to properly define each piece. For this reason, a quality indicator had to be proposed that could objectively identify whenever a respiratory signal contained errors. Furthermore, from the idea to characterise the movements of a subject, and by changing the measuring point from a frontal to a lateral perspective to avoid most of the occlusions, a new method based on obtaining the movement of the thoraco-abdominal region using dense optical flow was proposed. This method makes us of the phase of the optical flow to obtain the respiratory signal of the subject, while using the modulus to compute a quality index.Finally, regarding the different signal processing methods used in this thesis to obtain the instantaneous frequency, there were none that could perform in real-time, making the analysis of the respiratory variability not possible in real-life systems where the signals have to be processed in a sample by sample basis. For this reason, as a final chapter a new implementation of the synchrosqueezing transform for time-frequency analysis in real-time is proposed, with the aim to provide a new tool for non-contact methods to obtain the variability of the respiratory signal in real-time.

DOCTORAL DEGREE IN ENVIRONMENTAL ENGINEERING

  • GASPARINI, ANDREA: Experimental and numerical modelling of CO2 behaviour in the soil-atmosphere interface. lmplications far risk assessment of carbon capture storage projects.
    Author: GASPARINI, ANDREA
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN ENVIRONMENTAL ENGINEERING
    Department: (DECA)
    Mode: Article-based thesis
    Deposit date: 07/02/2020
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: GRANDIA I BORRÀS, FIDEL | BRUNO I SALGOT, JORGE
    Committee:
         PRESIDENT: VOLTATTORNI, NUNZIA
         SECRETARI: FOLCH DURAN, ARNAU
         VOCAL: MAZADIEGO MARTINEZ, LUIS FELIPE
    Thesis abstract: CO2 geological storage is considered one of the options technologically viable in order to decrease the industrial emissions of this gas species that strongly contribute to the greenhouse effect in the atmosphere (IPCC, 2005). As naturally, oil and gas are stored in porous rocks that have the same key geological features required for CO2 storage, so CCS aim to recreate a natural process to trap carbon dioxide for millions of years into deep saline aquifer or depleted oil and gas fields. Episodic release of CO2 from underground can occur from either natural processes (i.e., mantle degassing, thermal decarbonation, volcanic areas) or industrial (geological storage of CO2, CCS). Because of leakage can occur at every step of a CCS project, monitoring assumes an important role not only during and after injection but also before in order to know the state of the entire site from deep underground (reservoir level) to surface. In this respect, the use of atmospheric dispersion numerical models helps predicting the dispersion of the CO2-enriched gas plume once emitted from underground and allows an accurate map of risk level through time under particular meteorological conditions. The aim of this PhD. project is to give a better understanding of CO2 behaviour in the unsaturated zone and its atmospheric dispersion. The results are obtained from experimental and numerical modelling of CO2 leakage from an artificial leakage site and from natural analogues applied to risk assessment for CCS sites. To reach the above-mentioned targets and to prove results, this research plan combines experimental activity on site and numerical modelling. The first part of the research plan consisted of a contribution in the PISCO2 project at the ES.CO2 facilities placed in Ponferrada (Spain). The objective of this project was to predict how the injected CO2 will move laterally and vertically in the unsaturated zone and to determine the critical parameters that will affect the ecosystems. This part has been published in a peer review journal and presented in an international congress.The second part of the PhD. project has focused on the study of two natural analogues in volcanic areas. Natural analogues provide evidences of the impact of CO2 leakage, for both sites two approaches have been followed: a) direct measurement of air concentration and b) numerical atmospheric modelling with the TWODEE2 code. The study of CO2 emissions in natural systems provides a valuable information on the assessment and quantification of potential risks related to underground carbon storage leakage. Emissions of CO2 are studied in a large variety of geological environments, i.e., sedimentary basins, active andnon-active volcanic areas, seismically-active regions, and geothermal fields. Because of the physics of carbon dioxide gas, e.g., colourless, odourless, higher density compared to air, its accumulation may result hazardous and even lethal for life. The objective of atmospheric dispersion modelling is to predict how will move the plume, generated by a leakage in natural degassing systems and CCS sites.Results obtained from this doctorate provide:¿Coupling experimental and numerical data in order to test new methods and/or numerical codes;¿New elements to the knowledge of CO2 behaviours in the unsaturated zone as seen at PISCO2;¿New clues on non-invasive monitoring techniques for CCS sites and natural analogues;¿The usefulness of studying natural analogues;¿The usefulness of the SAP system, as a good method to evaluate high gas emissions from underground;¿The efficiency of atmospheric modelling as a valuable methodology in the risk assessment;¿The importance of risk assessment maps in active degassing areas;¿The need of production of forecasting maps to evaluate dangerous scenarios.¿Numerical models (multiphase transport and atmospheric gas dispersion) are proved to be useful tools to predict gas behaviour inthe vadose zone and in the near-grou

DOCTORAL DEGREE IN GEOTECHNICAL ENGINEERING

  • RODRIGUEZ FRETE, MARIANA: Análisis numérico termo-mecánico y termo-higrométrico del hormigón expuesto a altas temperaturas.
    Author: RODRIGUEZ FRETE, MARIANA
    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: (DECA)
    Mode: Normal
    Deposit date: 06/11/2020
    Reading date: 16/12/2020
    Reading time: 16:00
    Reading place: ETSECCPB: VIDEOCONFERÈNCIA PER COVID 19 meet.google.com/yet-xrax-pdh
    Thesis director: CAROL VILARASAU, IGNACIO | LOPEZ GARELLO, CARLOS MARIA
    Committee:
         PRESIDENT: RUIZ LÓPEZ, GONZALO
         SECRETARI: PRAT CATALAN, PERE
         VOCAL: XOTTA, GIOVANNA
    Thesis abstract: Concrete is one of the most used materials in construction, and its application spans to all kinds of structures. For this reason, concrete has been the subject of intense study. In spite of that, there are still apects of its behavior that are not completely unerstood and require further research, such as those related to material durability, i.e. aspects related to the deterioration due to environmental actions such as for instance high temperatures, chemical or biological attack, etc. The present doctoral thesis focuses on the numerical study of concrete behavior subject to high temeperatures. Nowadays it seems clear that two main mechanisms exist that may lead to material failure or spalling (sudden explosive detachment or outer concrete layers) when concrete is exposed to high temperatures (fire). The first one is related to the develoment of high compresive stresses as the result of restricted termal dilation, and the second one is related to the development of vapor pressures within the material pores due to water vaporization. Both mechanisms are studied independently in this Thesis.In this context of the high temeprature effects in concrete, most numerical studies in the literature are based on a macroscopic approach, in which the material is considered a homogeneous continuum. However, it is clear that concrete is a heterogeneous material and that its overall behavior strongly depends on the response of each one of its constituents and the interaction between them. In this regard, the approach to the first of the two above-mentioned mechanisms, is carried out using two independent Finite Element codes in-house developed within the MECMAT-UPC research group: the duffusion code DRACFLOW and the meso-mechanical code DRAC. In both analyses, the material is considered as heterogeneous, composed of aggregates and mortar, each of them with different thermal and mechanical properties. The results of various uncoupled calculations under uniform and non-uniform temperature distrubutions, are compared to experimental results from the literature. Numerical results of a thermo-mechanical análisis are also presented. These results represent spalling more realistically, in better agreement with the behavior observed in coulmns exposer to the fire action.On the other hand, a main contribution of this thesis is the formulation and implementaiotn of a hygro-mechanical TH model (second failure mechanism mentioned above). In this TH formulation, temperature and water vapor pressure are conssidered the primary variables, from which the rest of the field and state variables may be obtained. A novel formulation is also proposed to relate saturation degree and vapor pressure, which is based on the combination of the pore distribution curve with some fundamental equations of termodinamical equilibrium between water vapor and liquid water in the pores. Various 1-D examples of applcation are selected for the validation of the model. The results obtained succeed in reproducing satisfactorily a variety of complex aspects of the phenomenon. Finally, results are presented of the application of the model to the TH analysis of a meso-structural concrete sample
  • TOURCHI, SAEED: THM analysis of argillaceous rocks with application to nuclear waste underground storage
    Author: TOURCHI, SAEED
    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: (DECA)
    Mode: Normal
    Deposit date: 27/10/2020
    Reading date: 04/12/2020
    Reading time: 10:30
    Reading place: ETSECCPB- Defensa per vidoconferència COVID-19: https://meet.google.com/mnk-hgsu-qkz
    Thesis director: GENS SOLE, ANTONIO | VAUNAT, JEAN
    Committee:
         PRESIDENT: FERRARI, ALESSIO
         SECRETARI: OLIVELLA PASTALLE, SEBASTIAN
         VOCAL NO PRESENCIAL: ARMAND, GILLES
    Thesis abstract: Argillaceous rocks (Stiff sedimentary clays) provide the geological background to many civil engineering projects. In recent years, interest in these types of material has increased, because they are being considered as potential host geological media for underground repositories of high-level radioactive waste (HLW). The possible use of these types of clay as geological hosts for radioactive waste has prompted the construction of several underground laboratories. Among the very different topics addressed in the Underground Research Laboratories (URLs), the thermo-hydro-mechanical (THM) behaviour of the host rock is the one that most concerns the present research. In situ observations have revealed a considerable number of coupled THM processes in the operation of an HLW repository.In this context, the main objective of the present study is to describes the performance, observations and interpretation of the full-scale in situ heating test conducted on Callovo-Oxfordian (COx) claystone in the Meuse / Haute-Marne URL simulating a heat-emitting, high-level radioactive waste disposal concept. The test is fully instrumented, and attention is focused on the near-field region's the THM behaviour consisting of the sleeve surrounding the heater and the host rock. The interpretation of the test is assisted by the performance of a coupled numerical analysis based on a coupled formulation incorporating the relevant THM phenomena. The calculations have used a reference isothermal constitutive model especially developed for this type of material. The reference model later has been extended to non-isothermal condition by incorporating thermal dependency of strength parameters and stiffness. The thermomechanical model has been successfully used in the simulation of triaxial tests on COx claystone. The numerical analysis performed has proved able to represent the progress of the experiment very satisfactorily. The performance and analysis of the in-situ test has significantly enhanced the understanding of a complex THM problem and have proved the capability of the numerical formulation and non-isothermal constitutive model to provide adequate predictive capacity.

DOCTORAL DEGREE IN MARINE SCIENCES

  • LABARRE, AURELIE: GENOME BASIS FOR FUNCTIONAL DIFFERENTIATION IN UNCULTURED LINEAGES OF MARINE BACTERIVORES
    Author: LABARRE, AURELIE
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN MARINE SCIENCES
    Department: (DECA)
    Mode: Article-based thesis
    Deposit date: 06/10/2020
    Reading date: 26/11/2020
    Reading time: 11:00
    Reading place: Institut de Ciències del Mar. Defensa per videoconferència (COVID-19) https://meet.google.com/fwc-prmv-hbn
    Thesis director: MASSANA MOLERA, RAMON
    Committee:
         PRESIDENT: RUIZ TRILLO, IÑAKI
         SECRETARI: VAQUÉ VIDAL, DOLORS
         VOCAL NO PRESENCIAL: PIGANEAU, GWENAËL
    Thesis abstract: In the vast network of the ocean, microbes are abundant and unevenly distributed. As an important microbial component, the protists play a key role in global biogeochemical cycles and contribute to the recycling of nutrients necessary to sustain life on Earth. These unicellular eukaryotes exist and function as primary producers (drivers of photosynthesis), decomposers, parasites or as trophic linkers in aquatic food webs. Phagotrophic species, which acquire nutrition through feeding on other organisms, are commonly understudied due to the difficulty in culturing them. The recent characterization of their genomic and metabolic diversity starts to unveil their great ecological relevance in the oceans. In this dissertation, we focused on heterotrophic flagellates, the main bacterial grazers in marine systems, and especially on the MArine STramenopile (MAST) lineages that display numerous uncultured and, therefore, undefined species. The aim was to elucidate their ecological importance in marine food webs by understanding their presumed trophic strategy: phagocytosis, a process only well characterized in animals as an immune system response. We first attempted to provide new reference genomes of MAST species using single cell genomic sequencing and a co-assembly approach. Thus, we assembled 15 draft genomes from different MAST lineages, and predicted their gene repertoire with the objective to characterize specific genes related to their trophic strategy. Our comparative genomics analysis indicated that all MAST species were phagotrophs. We then targeted peptidases involved in prey digestion as well as proton pumps for vacuole acidification, but we did not find preferential genes specific for phagocytosis. In addition, this study revealed the relevant presence of rhodopsin proteins that may contribute in the acidification of the phagolysosome. In the second paper, we did a functional study of MASTs using metatranscriptomics in order to gain access to their gene expression within the natural environment. To do so, we started a grazing experiment with a natural sample from the Mediterranean Sea: in a controlled microcosm in the dark, we followed the cell growth of a natural community where we aimed to enrich for heterotrophic flagellates and therefore phagocytosis. We showed an increase in the relative abundance of heterotrophs, as compared with phototrophs, when phagocytosis occurred. Using the previously established reference genome collection of a few MASTs, we were able to target the MAST reads in the metatranscriptome and analyze the expression profile of genes involved in phagocytosis for a couple of MAST-4 species. Cathepsins and other digestive enzymes were highly expressed when bacterial consumption was observed. Finally, a similar experiment was conducted with a cultured organism, Cafeteria burkhardae, a cosmopolitan heterotrophic flagellate that proved to be a good model to study bacterivory within the Stramenopiles. Results demonstrated distinct expression profiles depending on the growth phase of this species. Upregulated genes at the Exponential phase were related to DNA duplication, transcription, translation, and phagocytosis, whereas upregulated genes in the Stationary phase were involved in signal transduction, cell adhesion and lipid metabolism. Phagocytosis genes, like peptidases and proton pumps, were highly expressed and could be used to target this ecologically relevant process in marine ecosystems. This thesis contributes to the understanding of the community of marine bacterial grazers, which include the smallest phagotrophs in the ocean, with a focus on their functional behavior within the natural and complex protistan assemblage.
  • ROS CHAOS, SERGIO: The transport and environmental impacts of cruise ships. Application to the case of the Port of Barcelona
    Author: ROS CHAOS, SERGIO
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN MARINE SCIENCES
    Department: (DECA)
    Mode: Article-based thesis
    Deposit date: 06/11/2020
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: SANCHEZ-ARCILLA CONEJO, AGUSTIN | SAURI MARCHAN, SERGI
    Committee:
         PRESIDENT: MARTÍNEZ MARÍN, JESÚS EZEQUIEL
         SECRETARI: ESPINO INFANTES, MANEL
         VOCAL NO PRESENCIAL: CAMARERO ORIVE, ALBERTO
    Thesis abstract: The rapid evolution of the cruise industry in the last 50 years is evident. In the nineteenth century, cruise ships were simple modes of transport used by immigrants to travel on transoceanic voyages from Europe to North America in search of a better future. Now, they have become authentic floating cities full of amenities and activities to do on board, whose main objective is leisure and pleasure. Passengers no longer go on a cruise ship simply to get from one point to another. Instead, they seek a unique experience on the ship and do not care so much about the final destination. For this reason, many experts consider that cruise ships have become a travel destination in themselves.This evolution of the concept of cruise ship that occurred in the 1970s has not been easy. It has led to a set of problems that have significantly affected ports and the cities, and to which they have had to adapt.The main change is associated with the increase in size of the ships to accommodate more passengers and all the on-board activities. To receive this type of ships, ports have had to adapt their berthing line, maritime station, adjacent esplanade and road accesses, among other factors. Cruise ships have been increasing in size every year. In 2009, a ship reached 360 m in length and 222,900 GT of gross tonnage. Given this gigantism of ships, this thesis aims to verify and analyse whether an increase in cruise ship capacity and size is justified and supported by economies of scale. The large passenger capacity of these ships also entails difficulties in managing passenger mobility, especially when more than two cruises concur in the same time slot. In this case, the disembarkation operation becomes very complex, since passengers all leave at once and in a short period of time. This thesis analyses the mobility of passengers and studies the main variables that explain disembarking operations. Another important aspect is the impact that cruise ships have on the environment. Moving cruise ships at service speed requires a large amount of fuel. Consequently, polluting gases, mainly nitrogen oxides, sulfur oxides, suspended particles and greenhouse gases, are emitted in greater amounts into the environment. Many voices have been raised in the civilian population and public administrations that reject cruise tourism. For this reason, by 2020, more restrictive environmental regulations had been created, mainly limiting the sulfur content in marine fuels to 0.5%. Shipowners have various options to meet these requirements: use scrubbers together with catalytic reduction devices, use distilled fuels and less pollutants, the cold ironing solution to connect electrically at the docks to obtain energy or use liquefied natural gas (GNL) as an alternative fuel.The last section of this thesis tries to determine whether LNG could be the most valid option for cruise lines to mitigate emissions to the environment. LNG almost completely eliminates emissions of sulfur oxides and particles. Nitrogen oxides and CO2 are reduced by 90% and 20% respectively. Furthermore, the price of LNG is almost half that of heavy fuel oil, which makes LNG economically attractive. The idea of adopting LNG as a cruise fuel is quite new. Very few cruise ships in the world are adapted to this system. Therefore, an analysis and study of its viability is advisable and may help cruise companies to decide whether to adopt LNG as the majority fuel for cruise ships.

DOCTORAL DEGREE IN MATERIALS SCIENCE AND ENGINEERING

  • CASTEJÓN GALÁN, MARÍA DEL PILAR: Development of mono and multilayer membranes of polypropylene and ethylene-propylene copolymers via cast film extrusion and stretching
    Author: CASTEJÓN GALÁN, MARÍA DEL PILAR
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN MATERIALS SCIENCE AND ENGINEERING
    Department: (CEM)
    Mode: Temporary seizure
    Deposit date: 28/10/2020
    Reading date: 17/12/2020
    Reading time: 11:15
    Reading place: Sala de Conferències d'ESEIAAT, edifici TR5, Terrassa - Videoconferència per COVID19: meet.google.com/gux-rtoi-odz
    Thesis director: ARENCON OSUNA, DAVID
    Committee:
         PRESIDENT: VELASCO PERERO, JOSE IGNACIO
         SECRETARI: MARTÍNEZ LÓPEZ, MÓNICA
         VOCAL: FERNÁNDEZ RENNA, ANA INÉS
    Thesis abstract: This dissertation investigates the three-stage method MEAUS (melt-extrusion, annealing, and uniaxial stretching) for producing microporous membranes. This method for membrane preparation is a solvent-free process based on the stretching of semicrystalline polymer films containing a row-nucleated lamellar structure. In this regard, the first section of this thesis is dedicated to establishing an initial set of requirements based on the ability of different polyolefin materials for the formation of microporous membranes. The influence of the polymer matrix composition and the architecture structure on the flow-induced crystallization was studied. This was done using two linear polypropylenes having different molecular weights, and blending them with branched and very fluid PP resins. Lower porosity and permeability values were observed when low molecular weight polypropylenes were employed. Under the same processing conditions, the more prolonged relaxation time behavior of high molecular weight resins constituted the main factor in maintaining the macromolecular alignment for the generation of a row-lamellar crystalline structure. In the second part of this research work, heterophasic and random copolymers of polypropylene¿ethylene were selected to study the influence of ethylene comonomer and its distribution along the polymer backbone. Most of these polymers can form a planar stacked lamellar morphology with a high crystalline orientation by selecting appropriate processing conditions. From a process engineering standpoint, the influence of the extrusion draw ratio was analysed, and in-depth study concerning the annealing and uniaxial strain stages was performed. After annealing, the films were subjected to a uniaxially stretching step where the films are deformed along the machine direction. First, to generate pores at room temperature and subsequently stretched at a high temperature to enlarge the pore size by increasing lamellar separation. This thesis was also conducted as part of a comprehensive study aimed at evaluating the effect of temperature in the stages of extrusion, annealing, and uniaxial strain, as well as the use in some cases of extreme strain rates and strain extents. High levels of molecular orientation can be obtained with high extrusion draw ratios and fast cooling. Regarding the annealing process, an increment in temperature gave rise to a greater molecular orientation and a rearrangement of polymer chains in both the crystalline and amorphous phases, which led to an increase in crystallinity and molecular orientation. A close relationship was found between the starting crystalline characteristics and annealing and stretching conditions that affected the final porous morphology, and the trends registered for permeability. The last section of this thesis is devoted to ascertaining the effects of mineral fillers (CaCO3 and talc) on the crystallization and mechanical behavior of multilayer polypropylene/high density polyethylene microporous membranes. Celgard initially developed PP/PE/PP trilayer separators. This multilayer system can be produced by various processes such as lamination and co-extrusion, which allows combining the lower melting temperature of PE with the high-temperature strength of PP. The crystallization and crystalline orientation were affected by both the flow-induced crystallization and the nucleating mechanism of the fillers. A synergistic effect was observed in the filled samples due to the generation of pores during the uniaxial stretching stages (MEAUS method) along with the debonding mechanisms of mineral fillers from the polymeric matrix, which promoted the formation of larger pores giving rise to a change in membrane permeability. The agglomeration of fillers in the composites affected the mechanical properties, the average membrane pore size, and pore size distribution.
  • HAMOUDA, INES: Synthesis and characterization of plasma-treated liquid and hydrogels for bone cancer therapy
    Author: HAMOUDA, INES
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN MATERIALS SCIENCE AND ENGINEERING
    Department: (CEM)
    Mode: Temporary seizure
    Deposit date: 29/10/2020
    Reading date: 16/12/2020
    Reading time: 10:30
    Reading place: EEBE- Videoconferència per COVID-19 https://meet.google.com/guz-pxzk-meo
    Thesis director: CANAL BARNILS, CRISTINA | LABAY, CEDRIC PIERRE
    Committee:
         PRESIDENT: GARCÍA MARTÍNEZ, MARÍA DEL CARMEN
         SECRETARI: ESPAÑOL PONS, MONTSERRAT
         VOCAL: NICOL, ERWAN
    Thesis abstract: This PhD Thesis tallies with the Starting Grant project funded by the European Research Council (ERC) entitled ¿Atmospheric Pressure plAsma meets biomaterials for bone Cancer HEaling¿ (APACHE) and has been carried out within the Biomaterials, Biomechanics and Tissue Engineering group (BBT) at the Barcelona East School of Engineering (EEBE) of the Universitat Politècnica de Catalunya (UPC). This project falls within in the area of Plasma Medicine, a new branch of medical technologyencompassing physics, biology, medicine and chemistry. One of the main fields of interest in Plasma Medicine is cancer therapy. During the last decade, the anticancer capacity of cold plasmas has been illustrated in different cancer cell lines such as breast, skin, lung, pancreas, cervix or brain and has shown ability to kill cancer cells without damaging the surrounding tissues.This PhD Thesis is focused on investigating potential novel vehicles of plasma-treated liquids for bone cancer with the aim to provide an alternative to the current treatments (i.e. surgery, chemotherapy, radiation therapy and cryosurgery) that are not completely effective.Cold plasma sources can be used to treat liquid media, thereby generating plasma-treated liquids, which can be applied to the cancer cells afterwards. Reactive oxygen and nitrogen species are generated from cold plasmas, which have been related to the biological effects of plasmas and plasma-treated liquids. Despite the exact mechanisms are not completely described yet, the reactive species generated are thought to be the main responsible of the biological effects of plasmas. Many of the radicals generated during the discharge can contribute to complex reactions in liquids: formation of other short and long-lived species in the solution. As plasma-treated liquids will probably be washed in the body through the blood flow when injected, another option for the reactive species transport should be employed.Given the high capacity of hydrogels to store liquids, and their proven capacity as drug delivery agents, the use of biocompatible hydrogels will be studied in this PhD Thesis as novel vehicles for plasma-generated reactive species for bone cancer treatment. This may allow avoiding invasive surgery to the patient, as hydrogels can be used to target tumours by injection. Within this context, in this PhD Thesis the effect of the atmospheric pressure plasma jet will be investigated in liquids and hydrogels to develop novel vehicles for plasma-based therapies.In the first place, a literature review on plasma-treated polymers for biomedical applications will be presented, with special emphasis on the future evolution and new possibilities arising in the treatment of polymer solutions or hydrogels by cold plasmas for biomedical applications.In a first experimental step, the efficiency of direct plasma treatment will be compared to plasma treated or conditioned media with regard to their effects on healthy and cancer bone cells. The concentration of reactive species generated in cell culture media in different plasma treatment conditions will be related to the biological effects observed.Then, the effect of plasma treatment will be carefully studied on the chemistry and physico-chemical properties of different hydrogel-forming polymers: natural (alginate), semi-synthetic (methacrylated gelatin) and synthetic (poly(oxide)ethylene based triblock copolymer) polymers. The generation, stability and release of reactive species generated in solution from plasma will be discussed regarding the different kinds of polymers with different hydrogel-forming ability employed. The potential of polymer solutions and hydrogels as reservoirs and vehicles of reactive species from cold plasmas will be examined here.
  • ZHENG, YAFENG: Assessment of corrosion-induced damage in the mechanical contact response of cemented carbides a different length scales
    Author: ZHENG, YAFENG
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN MATERIALS SCIENCE AND ENGINEERING
    Department: (CEM)
    Mode: Article-based thesis
    Deposit date: 26/10/2020
    Reading date: 11/12/2020
    Reading time: 11:00
    Reading place: EEBE_ Defensa per videoconferència (COVID 19) - https://meet.google.com/dfj-xfky-fxe
    Thesis director: LLANES PITARCH, LUIS MIGUEL | FARGAS RIBAS, GEMMA
    Committee:
         PRESIDENT: SÁNCHEZ HERENCIA, ANTONIO JAVIER
         SECRETARI: JIMENEZ PIQUÉ, EMILIO
         VOCAL: ALVAREDO OLMOS, PAULA
    Thesis abstract: Cemented carbides, also referred to as hardmetals, are composite materials consisting of brittle refractory carbide phase (generally WC) embedded in a metallic matrix. Such microstructure leads to an outstanding combination of hardness, wear resistance and toughness. This makes hardmetals first materials in several highly demanding applications, e.g. cutting or forming of metallic alloys, as well as mining operations.Several of the above applications imply exposure to chemically aggressive media, such as lubricants, petrochemical and mine slurries, seawater, etc. Under these conditions, it has been shown that failure induced under applied load is accelerated, and corresponding service life may be significantly shortened. In this regard, the detrimental corrosion-related effects on tribological response and effective wear resistance of cemented carbides have aroused the greatest concern. However, investigations addressing similar information linking corrosion-induced damage and contact mechanical response at different length scales are quite limited.Within the above framework, the first part of this thesis was devoted to carry out a systematic and comprehensive study about corrosion-induced damage and residual strength (damage tolerance) for four microstructurally different hardmetals exposed to various corrosive media. It is found that acidic medium led to higher corrosion rates and more significant strength degradation than those from neutral and basic ones. Regarding degradation mechanisms, it is evidenced that corrosion starts at binder pool centers and evolves towards binder/WC interfaces when exposed to acid solution, while in the basic one it is initially located at binder/WC interfaces and subsequently expands into the ceramic particles. The subsequent sections were focused on assessing the corrosion-induced changes on the mechanical contact response of hardmetals through an increasing length scale (from 100s nanometers to 1000s microns). First, nanoindentation and nanoscrach techniques were employed to assess the influence of corrosion on the mechanical integrity of hardmetals. Corrosion-induced changes on corresponding response and damage scenario are discussed. It is concluded that dissolution of metallic phase becomes critical as it leads to an effectively lessened mechanical integrity. A similar investigation was then extended to a higher length scale range (from 10s to 100s of microns in depth), combining relatively long corrosion times with pyramidal indentation and sliding contact (microscratch) tests, in order to evaluate corrosion-induced changes on both load-bearing capability and damage scenario of hardmetals. Results reveal that mechanical contact strength and resistance to crack extension are significantly reduced after exposure to corrosive media. Such lessening effects are found to depend on the ratio between indentation and/or scratch depth and thickness of the corroded layer. Alike pronounced corrosion influence is evidenced in surface and subsurface damage scenarios regarding the crack propagation behavior.Finally, an even higher length scale (up to 1000 of microns) was introduced by combining Hertzian indentation techniques and variable corrosion times. Corrosion effects on corresponding mechanical response and damage were assessed for hardmetals with metallic binders of different chemical nature. Results indicate significant corrosion-induced changes on indentation stress-strain response and damage scenario. In this regard, critical loads for emergence and evolution of specific damage events - ring and radial cracks, and even specimen failure - are proposed as figures of merit for material selection under the combined action of corrosion and contact loading. It points out the consideration of the synergic interaction between corrosion resistance and hardness/toughness correlation for microstructural design optimization of hardmetals under service-like conditions.

DOCTORAL DEGREE IN NATURAL RESOURCES AND THE ENVIRONMENT

  • FÀBREGA ALSINA, CARLES: Albitization of the granitic basement of the Guilleries and Roc de Frausa Massifs (NE Spain) in relationship to the Permian - Triassic palaeosurface.
    Author: FÀBREGA ALSINA, CARLES
    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 NATURAL RESOURCES AND THE ENVIRONMENT
    Department: Department of Mining, Industrial and ICT Engineering (EMIT)
    Mode: Normal
    Deposit date: 06/11/2020
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: PARCERISA DUOCASTELLA, DAVID | GÓMEZ GRAS, DAVID MANUEL
    Committee:
         PRESIDENT: ALFONSO ABELLA, MARIA PURA
         SECRETARI: MARTÍN MARTÍN, JUAN DIEGO
         VOCAL: THIRY, MÉDARD
    Thesis abstract: The granitic basement below the Triassic unconformity in the Guilleries and Roc de Frausa massifs (NE Iberia), presentswidespread red stained facies characterized by plagioclase albitization, biotite chlhoritization, K-feldspar microclinization andquartz precipitation. These main alterations are accompanied by precipitation of secondary hematite, maghemite, Cesynchisite,calcite and apatite and replacement of monazite by secondary monazite.The alteration forms a 150-200 m thick vertical profile beneath the regional Triassic unconformity. The most intense andpervasive alteration occurs in the upper part, close to the Triassic unconformity, and progressively decreases towards depthand becomes restricted to the fracture walls in the lowermost part. The alteration presents a large lateral continuity and canbe followed along tens of kilometers. This spatial arrangement below the Triassic unconformity indicates that the alterationwas probably triggered by the interaction of the granites with stable and long-lasting groundwater tables. The oxygen isotopecomposition of the albitized plagioclase (11-13¿), the microclinized K-felds par (12-14¿) and s econdary quartz (¿ 12¿)systematically have higher values respect to the primary counterparts and suggest that albitization developed at temperaturesaround 55ºC, at a depth of several hundreds of meters below surface. The dating of the microclinized K-feldspar by K-Ar andthe secondary monazite by U-Th-Pbtotal occurring in the red stained albitized rocks indicates that the alteration developedduring Permian - Triassic times. The zone between the albitized profile and the true palaeosurface was probably occupied bya thick regolith eroded during Early Triassic times.All these features strongly support that this red albitized profiles record a widespread Na-alteration of the crystallinebasement formed in close relationship with the Permo- Triassic palaeosurface and the salty environtments of the Permo-Triassic landscape. Similar Permian - Triassic red albitization profiles have been reported in the French Central Massif andthe Polish Sudetes, pointing to the hyphotesis that this kind of albitization was a common process that affected the Variscanbasement of Western Europe situated relatively close to the surface during Late Permian to Early Triassic times.

DOCTORAL DEGREE IN PHOTONICS

  • GONZÁLEZ CUADRA, DANIEL: A cold-atom approach to topological quantum matter across the energy scale
    Author: GONZÁLEZ CUADRA, DANIEL
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN PHOTONICS
    Department: Institute of Photonic Sciences (ICFO)
    Mode: Normal
    Deposit date: 28/10/2020
    Reading date: 11/12/2020
    Reading time: 10:00
    Reading place: ICFO: Defensa per videoconferència per COVID19 http://s.ic.fo/dQ3uz
    Thesis director: LEWENSTEIN, MACIEJ | BERMÚDEZ CARBALLO, ALEJANDRO
    Committee:
         PRESIDENT: ZOLLER, PETER ALBERT
         SECRETARI: CHANG, DARRICK
         VOCAL: BAÑULS POLO, MARIA CARMEN
    Thesis abstract: The outstanding progress achieved in the last decades to isolate and manipulate individual quantum systems has revolutionized the way in which quantum many-body phenomena, appearing across Nature's different energy scales, can be investigated. By employing atomic systems such as ultracold atoms in optical lattices, an enormous range of paradigmatic models from condensed-matter and high-energy physics are being currently studied using table-top experiments, turning Feynman's idea of a quantum simulator into a reality.Quantum simulators offer the possibility to gather information about complex quantum systems, which are either not accessible to experiments or whose properties can not be easily derived using standard analytical or numerical approaches. These synthetic quantum systems can be designed precisely such that they are described under the same models as natural systems, and their remarkable control allows to probe the relevant phenomena associated to them. Apart from their quantum simulation capabilities, atomic systems can also be employed to generate quantum matter with novel properties beyond those found in Nature, offering interesting prospects for quantum technological applications. In this thesis, we investigate the possibilities that cold-atom systems present to address, in particular, quantum matter with non-trivial topological properties. Using mixtures of ultracold atoms, we analyze various quantum simulation strategies to access several many-body phenomena for which a satisfactory understanding is still lacking. Moreover, we show how such platforms display strongly-correlated topological effects beyond those found in natural systems. We first focus on models inspired by condensed-matter physics. More precisely, we propose how lattices dynamics, similar to those described by phonons in solid crystals, can be implemented in an otherwise static optical lattice. By coupling the former to quantum matter using a mixture of bosonic atoms, we reproduce typical effects described by electronic systems, such as topological defects or charge fractionalization. We then extend these results and find novel features, from boson fractionalization to intertwined topological phases.We then consider the quantum simulation of high-energy-physics problems. By using Bose-Fermi mixtures, we show how non-perturbative phenomena characteristic of non-abelian gauge theories, such as quark confinement, emerge in simpler models that are within the reach of current technology. Finally, we investigate how the interplay between gauge invariance and strong correlations gives rise to various mechanisms to prepare robust topological order in near-term quantum simulators.In summary, our results show several connections between different areas of theoretical and experimental physics, and indicate how these can be harnessed further to advance our understanding of strongly-correlated quantum matter, as well as to utilize the latter for new technological applications.
  • NANDY, BIPLOB KUMAR: Development and study of novel mid-infrared frequency conversion sources
    Author: NANDY, BIPLOB KUMAR
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN PHOTONICS
    Department: Institute of Photonic Sciences (ICFO)
    Mode: Normal
    Deposit date: 28/10/2020
    Reading date: 02/12/2020
    Reading time: 15:00
    Reading place: ICFO: Videoconferència per COVID-19 http://s.ic.fo/Qy6AN
    Thesis director: EBRAHIM-ZADEH, MAJID | SUDDAPALI, CHAITANYA KUMAR
    Committee:
         PRESIDENT: AGNESI, ANTONIANGELO
         SECRETARI: COJOCARU, CRINA MARIA
         VOCAL: LAURELL, FREDRIK
    Thesis abstract: Tunable narrow-linewidth and broadband laser sources in the mid-infrared (mid-IR) wavelength range are extremely desirable in all time scales for their several useful applications in spectroscopy, imaging, optical communication and medical sciences to name a few. The one very important application of high-power tunable narrow-linewidth mid-IR laser sources in the 2 µm wavelength range is the ability to pump cascaded mid-IR optical parametric oscillators (OPO) for generating tunable wavelengths beyond 4 µm using semiconductor nonlinear crystals such as ZnGeP2 (ZGP) or orientation patterned GaAs (OP-GaAs). These crystals have very good linear and nonlinear optical properties along with good transparency beyond 4 µm wavelengths unlike oxide-based materials such as MgO:PPLN which have strong multi phonon absorption beyond 4 µm wavelengths. However, both ZGP and OP-GaAs cannot be pumped by commercially available 1 µm lasers due to linear and nonlinear absorptions below~2 µm wavelengths. In this thesis, we have demonstrated some very useful high-power narrow linewidth tunable 2 µm nanosecond and picosecond high-repetition-rate sources with very good spatial beam qualities. We have further demon strated a picosecond mid-IR idler-resonant MgO:PPLN based OPO with intra-cavity second-harmonic-generation (SHG). This helps in covering the essential wavelength gap between 1.064 µm and 1.45 µm when pumped by Yb- ber laser at 1.064 µm. This wavelength gap is generally not covered by MgO:PPLN based SROs that are signal resonant due to the material transparency of MgO:PPLN which doesn't allow the idler wave to go above ~4 µm wavelength, thereby restricting the signal wave from reaching below ~1.45 µm.Due to the requirement of synchronous pumping, the OPOs typically tend to be relatively bulky and of large size, which can restrict its practical utility in space-constrained applications. We address this challenge by demonstrating a compact picosecond high-repetition rate singly resonant (SRO) with intracavity-mirror-retro-re ector ber (IMRF) that enables two-fold reduction in the form-factor. This IMRF OPO demonstrates a high wavelength tunability from~1.45 µm to~4 µm with high spectral brightness and exceptionally good output beam quality. In our attempt to further reduce the size and complexity of nonlinear frequency conversion sources, we have demonstrated the rst single-pass optical parametric generation (OPG) and ampli cation (OPA) in MgO:PPLN with record high conversion e ciency of >59% without the requirement of any seed-laser. We have demonstrated a record-low pump threshold energy of 7.5 nJ which is remarkably small and opens a whole new area of research on single-pass frequency conversion devices based on OPG/OPA. Our system is highly tunable near~2 µm region with >8 W of single-pass output power while pumped with~14 W of pump power at 1064 nm. Finally, in this thesis, we have demonstrated the rst phase-locked picosecond OPO with record high output power and spectral bandwidth near~2 µm wavelength region. Such a device can be used as a high spectral brightness phase-locked super-continuum source for a huge array of applications
  • WINKLER, PAMINA: Novel planar photonic antennas to address the dynamic nanoarchitecture of biological membranes
    Author: WINKLER, PAMINA
    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: 19/10/2020
    Reading date: 27/11/2020
    Reading time: 11:00
    Reading place: ICFO: Videoconferència per COVID-19 http://s.ic.fo/LxpQG
    Thesis director: GARCÍA PARAJO, MARÍA
    Committee:
         PRESIDENT: WIENTJES, INA EMILIA
         SECRETARI: VAN HULST, NIEK
         VOCAL: SEZGIN, ERDINC
    Thesis abstract: The cell membrane is the encompassing protective shield of every cell and it is composed of a multitude of proteins, lipids and other molecules. The organization of the cell membrane is inextricably intertwined with its function, and sensitive to perturbations from the underlying actin cytoskeleton and the extracellular environment at the nano- and the mesoscale. Elucidating the dynamic interplay between lipids and proteins diffusing on the cell membrane, forming transient domains and (re)organizing them according to signals from the juxtaposed inner and outer meshwork, is of paramount interest in fundamental cell biology. The overarching goal of this thesis is to gain deeper insight into how lipids and proteins dynamically organize in biological membranes at the nanoscale. Photonic nano-antennas are metallic nanostructures that localize and enhance the incident optical radiation into highly confined nanometric regions (< 20 nm), leading to greatly enhanced light-matter interactions. In this thesis, we exploit an innovative design of planar gold nano-antenna arrays of different gap sizes (10-45 nm) and embedded in nanometric-size boxes. To elucidate nanoscale diffusion dynamics in biological membranes with high spatiotemporal resolution and single-molecule detection sensitivity, we further combine our nanogap antenna arrays with fluorescence correlation spectroscopy (FCS) in a serial and multiplexed manner. In this dissertation, we first describe the fabrication process of these planar gold nanogap antennas and characterize their performance by means of electron microscopy and FCS of individual molecules in solution. We demonstrate giant fluorescence enhancement factors of up to 104-105 times provided by our planar nanogap antennas in ultra-confined detection volumes and with single molecule detection sensitivity in the micromolar range. Second, we apply these planar plasmonic nano-antennas in combination with FCS for assessing the dynamic organization of mimetic lipid membranes at the nanoscale. For a ternary composition of the model membranes that include unsaturated and saturated lipids together with cholesterol, we resolve transient nanoscopic heterogeneities as small as 10 nm in size, coexisting in both macroscopically phase-separated lipid phases.Third, we add a Hyaluronic Acid (HA) layer on top of the model lipid membranes to emulate the effect of the extracellular environment surrounding native biological membranes. We extend our nano-antenna-FCS approach with atomic force microscopy and spectroscopy. We reveal a distinct influence of HA on the nanoscale lipid organization of mimetic membranes composed of lipids constituting the more ordered lipid phase. Our results indicate a synergistic effect of cholesterol and HA re-organizing biological membranes at the nanoscale. Fourth, we apply our planar nano-antenna platform combined with FCS to elucidate the nanoscale dynamics of different lipids in living cells. With our nanogap antennas we were able to breach into the sub-30 nm spatial scale on living cell membranes for the first time. We provide compelling evidence of short-lived cholesterol-induced ~10 nm nanodomain partitioning in living plasma membranes. Fifth, we demonstrate the multiplexing capabilities of our planar gold nanogap antenna platform combined with FCS in a widefield illumination scheme combined with sCMOS camera detection. Our approach allows recording of fluorescence signal from more than 200 antennas simultaneously. Moreover, we demonstrate multiplexed FCS recording on 50 nano-antennas simultaneously, both in solution as well as in living cells, with a temporal resolution in the millisecond range. The dissertation finishes with a brief discussion of the main results achieved in this research and proposes new avenues for future research in the field.

DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS

  • ARDANUY DELLA, ANTONI: DSP-BASED CW LIDARS for clouds and aerosol
    Author: ARDANUY DELLA, ANTONI
    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: 10/09/2020
    Reading date: 14/12/2020
    Reading time: 09:30
    Reading place: Videoconferència: meet.google.com/mnu-obrw-qda - (Aula Teleensenyament - B3 - ETSETB - Campus Nord)
    Thesis director: COMERON TEJERO, ADOLFO
    Committee:
         PRESIDENT: ARTAL LATORRE, EDUARDO
         SECRETARI: RODRIGUEZ GOMEZ, ALEJANDRO ANTONIO
         VOCAL: GONZÁLEZ PÉREZ, MIGUEL
    Thesis abstract: This thesis aims at exploring the limits of low peak-power, low-cost, all-semiconductor, compact lidars (laser radars) for range-resolved remote sensing of atmospheric aerosols and clouds. The systems investigated are based on laser diodes for emitter, avalanche photodiodes for the receiver, and digital signal processors for processing the returns from the atmosphere and the system control. The studied systems are built on the use of M-sequences and other derivated ones, which allows retrieving range-dependent information from the returning echoes, while having almost the same number of ones and zeros to maximize the transmitted average power for a limited peak power. The use of digital processors to generate the modulating sequences and to process the lidar returns allows for systems with agile reconfiguration capabilities and the use of very long sequences while keeping the processing time virtually negligible compared with the time employed to transmit the laser pulse-modulated output and receive the echoes from the atmosphere (the measuring time). The theorical developments are tested and demonstrated by the experimental results obtained with two lidar prototypes designed and build according the theoretical framework. The detection of cloud bases up to 8km with transmission peak powers of 125 mW in the near (almost visible) infrared (785 nm wavelength), with spatial resolution of 70 to 100 m and time resolution from 30 seconds to 4 minutes, has been achieved. Aerosols at lower altitudes are also observed in conditions of high aerosol load. In addition to further developments in low-cost lidar systems for detections of particles suspended in the atmosphere, the technical developments of this work pave also the way to the design of low-power systems por open path, range-resolved detection of gases, for example in industrial environments. After an introductory chapter, chapter 2 reviews the basic principles of lidar systems and focuses on continuous-wave systems with pseudorandom sequence modulation of the transmitted power and the constraints set by the requirement of a low peak-power transmitter. Chapter 3 reviews different types of power-modulating digital sequences that can be used, with the constraint of average 50% duty cycle, selects the best ones to be investigated in the experimental study, and unravels some of the issues associated to possible non-linear behavior of the photoreceiver. Chapter 4 presents the theoretical performance of the system, which is compared to a model that takes into account the technical constraints and non-idealities of the system building blocks. Chapter 5 sets out the complete design of the prototypes that have been built and tested, which are presented in chapter 6. Chapter 7 presents the tests and field results obtained with the prototypes built according to the design discussed in chapter 5. Chapter 8 presents the conclusions and outlines possible lines opened by the thesis work. Two appendices (chapter 9) develop further details on the detrimental effect of non-linear behavior in the receiver chain, and practical aspects of the alignment procedure between the lidar transmitter and the receiving optics.
  • CASAS MANZANARES, NOÉ: Injection of linguistic knowledge into neural text generation models
    Author: CASAS MANZANARES, NOÉ
    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: Temporary seizure
    Deposit date: 28/10/2020
    Reading date: 14/12/2020
    Reading time: 10:00
    Reading place: Videoconferència per COVID-19: meet.google.com/qjh-wihp-wff - (Aula Teleensenyament - B3 - Campus Nord)
    Thesis director: RODRIGUEZ FONOLLOSA, JOSE ADRIAN | RUIZ COSTA-JUSSA, MARTA
    Committee:
         PRESIDENT: BOLEDA TORRENT, GEMMA
         SECRETARI: BONAFONTE CAVEZ, ANTONIO JESUS
         VOCAL NO PRESENCIAL: SENNRICH, RICO
    Thesis abstract: Language is an organic construct. It emanates from the need for communication and changes through time, influenced by multiple factors. The resulting language structures are a mix of regular syntactic and morphological constructions together with divergent irregular elements. Linguistics aims at formalizing these structures, providing a rationalization of the underlying phenomena. However, linguistic information alone is not enough to fully characterize the structures in language, as they are intrinsically tied to meaning, which constrains and modulates the applicability of the linguistic phenomena and also to context and domain. Classical machine translation approaches, like rule-based systems, relied completely on the linguistic formalisms. Hundreds of morphological and grammatical rules were wired together to analyze input text and translate it into the target language, trying to take into account the semantic load carried by it. While this kind of processing can satisfactorily address most of the low-level language structures, many of the meaning-dependent structures failed to be analyzed correctly. On the other hand, the dominant neural language processing systems are trained from raw textual data, handling it as a sequence of discrete tokens. These discrete tokens are normally defined looking for reusable word pieces identified statistically from data. In the whole training process, there is no explicit notion of linguistic knowledge: no morphemes, no morphological information, no relationships among words, or hierarchical groupings. This thesis aims at bridging the gap between the neural systems and linguistics-based systems, devising systems that have the flexibility and good results of the former with a base on the linguistic formalisms, with the purposes of improving quality where data alone cannot and forcing human-understandable working dynamics into the otherwise black-box neural systems. For this, we propose techniques to fuse statistical subwords with word-level linguistic information, to remove subwords altogether and rely solely on lemmas and morphological traits of the words, and to drive the text generation process on the ordering defined by syntactic dependencies. The main results of the proposed methods are the improvements in translation quality that can be obtained by injecting morphological information into NMT systems when testing on out-of-domain data for morphologically-rich languages, and the control over the generated text that can be gained by means of linking the generation order to the syntactic structure.

DOCTORAL DEGREE IN STATISTICS AND OPERATIONS RESEARCH

  • CUADRADO GUEVARA, MARLYN DAYANA: Multistage scenario trees generation for renewable energy systems optimization.
    Author: CUADRADO GUEVARA, MARLYN DAYANA
    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: 22/10/2020
    Reading date: 30/11/2020
    Reading time: 12:00
    Reading place: FME: Videoconferència per COVID-19: https://meet.google.com/nsy-skve-ska
    Thesis director: HEREDIA CERVERA, FRANCISCO JAVIER
    Committee:
         PRESIDENT: RAMALHINHO DIAS LOURENÇO, HELENA
         SECRETARI: CASTRO PÉREZ, JORDI
         VOCAL: MORALES ESPAÑA, GERMAN ANDRES
    Thesis abstract: The presence of renewables in energy systems optimization have generated a high level of uncertainty in the data, which has led to a need for applying stochastic optimization to modelling problems with this characteristic. The method followed in this thesis is multistage Stochastic Programming (MSP). Central to MSP is the idea of representing uncertainty (which, in this case, is modelled with a stochastic process) using scenario trees. In this thesis, we developed a methodology that starts with available historical data; generates a set of scenarios for each random variable of the MSP model; define individual scenarios that are used to build the initial stochastic process (as a fan or an initial scenario tree); and builds the final scenario trees that are the approximation of the stochastic process. The methodology proposes consists of two phases. In the first phase, we developed a procedure similar to Muñoz et al. (2013), with the difference being that the VAR models are used to predict the next day for each random parameter of the MSP models. In the second phase, we build scenario trees from the Forward Tree Construction Algorithm(FTCA), developed by Heitsch and Römisch (2009a); and an adapted version of DynamicTree Generation with a Flexible Bushiness Algorithm (DTGFBA), developed by Pflugand Pichler (2014, 2015). This methodology was used to generate scenario trees for two MSP models. A first model, Multistage Stochastic Wind Battery Virtual Power Plantmodel (MSWBVPP model) and to a second model, which is the Multistage StochasticOptimal Operation of Distribution Networks model (MSOODN model). We developed extensive computational experiments for the MSWBVPP model and generated scenario trees with real data, which were based on MIBEL prices and wind power generation of the real wind farm called Espina, located in Spain. For the MSOODN model, we obtained scenario trees by also using real data from the power load provided by FEEC-UNICAMP and photovoltaic generation of a distribution grid located in Brazil. The results show that the scenario tree generation methodology proposed in this thesis can obtain suitable scenario trees for each MSP model. In addition, results were obtained for the model using the scenario trees as input data. In the case of the MSWBVPP model, we solved three different case studies corresponding to three different hypotheses on the virtual power plant¿s participation in electricity markets. In the case of the MSOODN model, two test cases were solved, with the results indicating that the EDN satisfied the limits imposed for each test case. Furthermore, the BESS case gave good results when taking into account the uncertainty in the model. Finally, the MSWBVPP model was used to study the relative performance of the FTCA and DTGFBA scenario trees, specifically by analyzing the value of the stochastic solution for the 366 daily optimal bidding problems. To this end, a variation of the classical VSS (the so-called ¿Forecasted Value of the Stochastic Solution¿, FVSS) was defined and used together with the classical VSS.

DOCTORAL DEGREE IN URBANISM

  • PACHECO DIAZ, JOSÉ IGNACIO: Cuernavaca: Ciudad de Fraccionamientos Residenciales de Baja Densidad (1900-1997)
    Author: PACHECO DIAZ, JOSÉ IGNACIO
    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 and Regional Planning (UOT)
    Mode: Normal
    Deposit date: 29/10/2020
    Reading date: 09/12/2020
    Reading time: 17:00
    Reading place: ETSAB (Per videoconferència-COVID 19) - UPC Campus Sud - enllaç: meet.google.com/spz-xeih-hpo
    Thesis director: ROCA BLANCH, ESTANISLAO | CUROS VILA, JUAN
    Committee:
         PRESIDENT: MONCLUS FRAGA, FRANCISCO-JAVIER
         SECRETARI: MORENO SANZ, JOAN
         VOCAL NO PRESENCIAL: VARGAS MATA, MARÍA ISABEL
    Thesis abstract: With this research I wanted to find out what the urban growth of Cuernavaca was like from 1900 to 1997, and understand the dynamics of that process in the context of a strong capitalism, in order to explain how the agricultural social land has been integrating into the city. The process started since the small village was 70 ha. large, until it reached an extension of 18 km2 and a medium size density of 180 hab./ ha, all of this without urban planification. Its urban shape was constraint by its topography since the Spanish foundation; the city is situated on an elongated and sloping hill located between two deep ravines which run almost parallel from north to south and limited its growth.My main hypothesis or statement is that the Cuernavaca urbanization model was the product of the process of formation of a medium-sized city, where the proximity to the great metropolis created a demand for second-home housing and the response came from the ruling classes through usurpation of social agricultural land, creating large extensions of land for urban speculation, due to the lack of a regulatory urban planning framework and the corruption. With this research I demonstrate how these urbanizations as formal residential low density subdivisions called `Fraccionamientos¿, have structured the current layout of Cuernavaca, a topic that led me to other topics closely related to this issue: that of real estate agents and their interests and strategies. The work is exemplified by the empirical review of two areas: Lomas de Ahuatlán on the hills to the west of the city, and to the east with the Llanos de Ahuatepec, where in the first third of the twentieth century, a governor and his family appropriated hundreds of thousands of square meters of social land creating large urbanizations the Vista Hermosa fraccionamiento in the company town style, which boosted growth towards the valley on the east of the historic center. In Lomas de Ahuatlán an extensive real estate development was created in 1997 together with a series of subdivisions that accompanied this urban growth. The trend of urbanization model was followed and replicated by other real estate agents who urbanized other areas of the city.These low-density suburban developments which grew in the form of subdivisions were originally destined as secondary residential housing for a high-income segment of the population, but over time and due to market saturation, they were adapted for middle-class first residence homes. However, the speed of this last settlement was limited both by the topographic characteristics of the city and by the low investment in infrastructure, which caused that for many years there were no bridges in the most important ravines. Taking into consideration that 90% of the land was social property ¿ `ejidal¿ or community property, real estate agents bought the land to farmers or community members, and in other cases they acted through dispossession or fraudulent legal action. This trend, which lasted six decades, doubled the urban land approximately every ten years, contributing to the rapid expansion of the city.In the last third of the 20th century the so-called `Colonias¿ or proletarian urbanizations were also created, with the pressure of urban social movements. This was another type of popular residential subdivision, with smaller plots, narrower streets, and no green areas. In this period working-class neighborhoods were created by invasion and subsequent social vindication, with great tolerance from the local governments of the ruling party. We can see how the growth of Cuernavaca from 1997 dropped and extended towards the periphery, especially to the conurbation with the municipalities to the south-west of Temixco, Jiutepec and Tejalpa, and at the same time, the supply of land multiplied, covering various strata and typologies.

ERASMUS MUNDUS DOCTORAL DEGREE IN INTERACTIVE AND COGNITIVE ENVIRONMENTS

  • MWANGI, EUNICE NJERI: Gaze-Based Interaction for Better Tutoring with Social Robots
    Author: MWANGI, EUNICE NJERI
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: ERASMUS MUNDUS DOCTORAL DEGREE IN INTERACTIVE AND COGNITIVE ENVIRONMENTS
    Department: Department of Management (OE)
    Mode: Change of supervisor
    Deposit date: 22/07/2020
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: DIAZ BOLADERAS, MARTA | CATALA MALLOFRE, ANDREU | RAUTERBERG, MATHIAS
    Committee:
         PRESIDENT: CHEN, LIN LIN
         SECRETARI: NEERINCX, MARK A.
         VOCAL: KIMANI, STEPHEN
    Thesis abstract: The central thesis of this work is that effective gaze behaviour can help build a shared understanding and mutual awareness between humans and robots, leading to positive outcomes in a tutoring interaction. Gaze behaviour is an essential cue for social engagement and coordinated action, principally for tasks that imply human-robot collaboration, such as tutoring. The work presented in this dissertation is a complilation of findings from three empirical studies designed to explore the design space of gaze-based interaction to enrich human-robot interaction in educational settings where robots assume tutor or trainer roles. In the first study, we examined how people perceive and interpret social cues from gaze exhibited by either a human or a robot tutor and whether they can accept the cues as help during learning interactions. We incorporated eye-tracking to examine gaze interaction during human-human and human-robot communications. We found that participants noticed the gaze cues from the robot tutor significantly more often compared to those of the human tutor. Consequently, we found that participants performed better with the robot tutor compared ot the human tutor. These initial findings provide design recommendations for gaze-based communications to improve learning performance during human-robot tutoring.Based on the results from the first study, we investigated how to implement gaze-based communication as an efficient help mechanism for robot-child tutoring. the objective was to examine childrobot gaze mechanisms to inform the robot's behaviour design as a facilitator of children's task-solving. We carried out simultaneous observations of th gaze of the child and the robo to examine the events of mutual gaze and gaze following patterns during the tutoring activity and to assess the impact of different child-robot coordinated gaze patterns on childrens behavious and performance. We found that if a robot tutor provides gaze-based support, chidren perform better during the tutoring activity compared to when a tutor does no offer such cues. We also found that more events of mutual gazing patterns between the child and the robot tutor improve children's awareness of the tutor's intention during the activity leading to better performance. Therefore, we concluded that increeasing gaze coordination between the child and the robot can improve performance and build mutual awareness during robot-based educative interventions. In the last study, we investigated the nature and dynamics of gaze-based human-robot interaction (HRI) in the context of tutoring. The objective was to examine intricate patterns of gaze interchanges between a child and a robot during the tutoring activity and to assess the impact of child-robot coordinated gaze on childre'ns behaviour and performance. We combined both observational and sequential lag methods to examine the relevant gaze sequences during a collaboratie tutoring activity. We found that apppropiate consequences and timing of the dyad's gaze behaviours between a child and a robot can lead to effective interactions between ac hild and a robot tutor. Based on these findings, we concluded that a robot tutor could influence the flow of the child's actions positively - if the child interprets the social cues appropiately- improving the task execution and the play experience. This new understanding of the dynamic nature of gaze behaviour during child-robot interaction contributes to the design of robot gaze behaviour, to build better robot-based interventions in education and therapy setting.s Overall, the findings from the user studies we have conducted provide new guidelines for how to design gaze-based cues of cmmunications to improve learning performances and promote positive human-robot tutoring interations.

ERASMUS MUNDUS DOCTORAL DEGREE IN SIMULATION IN ENGINEERING AND ENTREPRENEURSHIP DEVELOPMENT

  • BORCHINI, LUCA: High-fidelity surrogate models for parametric shape design in microfluidics
    Author: BORCHINI, LUCA
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: ERASMUS MUNDUS DOCTORAL DEGREE IN SIMULATION IN ENGINEERING AND ENTREPRENEURSHIP DEVELOPMENT
    Department: (DECA)
    Mode: Change of supervisor
    Deposit date: 27/10/2020
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: HUERTA CEREZUELA, ANTONIO | GIACOMINI, MATTEO | SEVILLA CÁRDENAS, RUBÉN
    Committee:
         PRESIDENT: MORGAN, KENNETH
         SECRETARI: ZLOTNIK MARTINEZ, SERGIO
         VOCAL: CUETO PRENDES, ELIAS
         VOCAL: GIORGIANI, GIORGIO
         VOCAL: OTHMER, CARSTEN
    Thesis abstract: Nowadays, the main computational bottleneck in computer-assisted industrial design proceduresis the necessity of testing multiple parameter settings for the same problem. Material properties,boundary conditions or geometry may have a relevant influence on the solution of thoseproblems. Consequently, the effects of changes in these quantities on the numerical solutionneed to be accurately estimated. That leads to significantly time-consuming multi-queryprocedures during decision-making processes. Microfluidics is one of the many fields affected by this issue, especially in the context of the design of robotic devices inspired by naturalmicroswimmers. Reduced-order modelling procedures are commonly employed to reduce thecomputational burden of such parametric studies with multiple parameters. Moreover, highfidelity simulation techniques play a crucial role in the accurate approximation of the flowfeatures appearing in complex geometries. This thesis proposes a coupled methodology basedon the high-order hybridisable discontinuous Galerkin (HDG) method and the proper generalized decomposition (PGD) technique. Geometrically parametrised Stokes equations are solved exploiting the innovative HDG-PGD framework. On the one hand, the parameters describing the geometry of the domain act as extra-coordinates and PGD is employed to construct a separated approximation of the solution. On the other hand, HDG mixed formulation allows separating exactly the terms introduced by the parametric mapping into products of functions depending either on the spatial or on the parametric unknowns. Convergence results validate the methodology and more realistic test cases, inspired by microswimmer devices involving variable geometries, show the potential of the proposed HDG-PGD framework in parametric shape design. The PGD-based surrogate models are also utilised to construct separated response surfaces for the drag force. A comparison between response surfaces obtained through the apriori and the a posteriori PGD is exposed. A critical analysis of the two techniques is presented reporting advantages and drawbacks of both in terms of computational costs and accuracy.
  • GARIKAPATI, HASINI: Computational uncertainity quantification in pressure-driven fracture processes
    Author: GARIKAPATI, HASINI
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: ERASMUS MUNDUS DOCTORAL DEGREE IN SIMULATION IN ENGINEERING AND ENTREPRENEURSHIP DEVELOPMENT
    Department: (DECA)
    Mode: Change of supervisor
    Deposit date: 28/02/2020
    Reading date: pending
    Reading time: pending
    Reading place: pending
    Thesis director: DIEZ MEJIA, PEDRO | VAN BRUMMELEN, EINAR HARALD | VERHOOSEL, CLEMENS V. | ZLOTNIK MARTINEZ, SERGIO
    Committee:
         PRESIDENT: DE GOEY, PHILIP
         SECRETARI: NOBILE, FABIO
         VOCAL: DE LORENZIS, LAURA
    Thesis abstract: Uncertainty quantification is important in assessing and predicting the performance of complexengineering systems and processes, especially in the absence of adequate experimental or real-worlddata. With the increase in computing power, computational uncertainty quantification is playing anincreasingly important role in decision making processes. We have studied the application ofuncertainty quantification to pressure-driven fracture processes, which are surrounded by uncertaintyas data are typically scant and available models are often rudimentary.In this dissertation we have developed a computational framework that combines simulationtechniques for pressure-driven fracturing processes with state-of-the-art uncertainty quantificationtechniques. On the one hand, the framework simulates the influence of uncertainties in, for example,formation data, on quantities of interest such as the fracture length. On the other hand, the uncertaintyquantification framework allows us to incorporate indirect measurement data, such as well pressures,in the simulation procedure. The developed computational uncertainty quantification frameworkimproves the understanding of the influence of uncertainties on pressure-driven fracture processes.

Last update: 26/11/2020 06:11:22.