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Public display of deposited theses

Presentació d'al·legacions a una tesi doctoral en el termini d'exposició pública

In accordance with the Academic Regulations for Doctoral Studies, doctors may request access to a doctoral thesis in deposit for consultation and, if there are, to send to the Permanent Commission of the Doctoral School the observations and allegations that they consider opportune on the content.

 

DOCTORAL DEGREE IN APPLIED MATHEMATICS

  • VENTURINI, CHIARA: Multiscale clutch models for cell mechanics
    Author: VENTURINI, CHIARA
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN APPLIED MATHEMATICS
    Department: (DECA)
    Mode: Normal
    Deposit date: 21/06/2022
    Deposit END date: 05/07/2022
    Thesis director: SAEZ VIÑAS, PABLO
    Committee:
         PRESIDENT: GARCÍA AZNAR, JOSÉ MANUEL
         SECRETARI: MUÑOZ ROMERO, JOSE JAVIER
         VOCAL: SUNYER BORRELL, RAIMON
    Thesis abstract: Integrin-based cell adhesion is a key mechanism in fundamental biological processes such as cell migration and wound healing, and in diseases like osteoporosis and cancer. For example, during migration, cells form adhesion complexes as they move, exerting tractions on the extracellular matrix (ECM), which enable the formation of protrusions. So far experimental research has demonstrated the role of ligand spacing and substrate rigidity in adhesion dynamics. Moreover, some mathematical models have provided fundamental understanding in cell adhesion. Specifically, the Clutch Model has been very successful in explaining how cells can sense force and consequently, how they respond to substrate rigidity. To exploit its potential, we have used it to address single cell durotaxis, the migration of a cell due to a stiffness gradient in the substrate. We provide a mechanistic rationale of durotaxis by integrating continuum models of cell migration with the stochastic clutch model. We show that a gradient in the ECM stiffness activates an asymmetric intracellular retrograde flow during the initial cell spreading. The competition between this flow and the polymerization velocity at the cell membrane, creates a polarized state that establishes cell migration directionality. Our theoretical framework confirms previous experimental observations and rationalizes why some cell types follow positive stiffness gradients, while others move toward softer region.Unfortunately, current clutch models also present some limitations. Adhesion complexes present a number of different adaptor proteins, and are able to link the actomyosin cortex in the interior of the cell to the ECM. The study of their composition and function has shown that the integrin-talin-actin chain serves as a mechanosensor and mechanotransducer of the external and internal forces. Current models simplify the composition and organization of the adhesion complex and use a phenomenological approach to reproduce cell scale variables. However, they fail in modelling the sub-scale molecular behaviour. These simplifications have limited our mechanistic understanding of cell adhesion. Therefore, we propose a multiscale clutch model that, from the physical and biological laws of the cell components, reproduces the mechanics of an adhesion complex as well as the dynamics of the subcellular molecules. Because the ligands distance is fundamental for cell adhesion mechanics, we include a space-dependent ligand distribution and compute the displacement of the substrate point-wise thanks to Green¿s functions. We also implement a detailed description of the talin rod. Given the importance of the recruitment of adaptor proteins in an adhesion complex, we implement the presence of vinculin binding sites (VBSs) and actin binding sites (ABSs) in the talin rod. Our results reproduce previous cell scale variables, but also reproduce the behavior of single adhesion molecules within the adhesion complex. Moreover, our results suggest that cell traction is mostly dependent on the complex adhesion size rather than ligand density. Our computational framework also allows us to easily manipulate VBSs and ABSs and analyze the effect of their depletion in cell adhesion mechanics. Our computational results reproduce experimental data of mouse embryonic fibroblasts, both with full-length talin and with different combinations of talin domains depletion, showing how the traction force changes with respect to the talin configuration. We believe that our detailed multi-scale model represents an important step forward in the understanding of cell adhesion, which can be further extended to account for other adhesion molecules and, e.g. , for the study of adhesion maturation. The multi-scale durotaxis model can be also used in a wider biological context, to engineer better biomimetic tissue constructs or to propose strategies for arresting tumor invasion.

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

  • GONZÁLEZ PÉREZ, FRANCISCO JAVIER: La Seu Episcopal d¿Ègara. El projecte d¿un conjunt cristià al segle V
    Author: GONZÁLEZ PÉREZ, FRANCISCO JAVIER
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN ARCHITECTURAL, CIVIL AND URBAN HERITAGE AND REFURBISHMENT OF EXISTING BUILDINGS
    Department: (RA)
    Mode: Normal
    Deposit date: 27/06/2022
    Deposit END date: 08/07/2022
    Thesis director: GIMÉNEZ MATEU, LUIS | SÁNCHEZ RIERA, ALBERTO
    Committee:
         PRESIDENT: SUREDA JUBANY, MARC
         SECRETARI: REDONDO DOMINGUEZ, ERNEST
         VOCAL: VALLS MORA, MARIA MONTSERRAT
    Thesis abstract: The aim of this research about built heritage is to understand how were the buildings placed in the monumental ensemble of Saint Peter of Terrassa configured, from middle 5th century to second half of the 6th century. To do this, a search of bibliographic and documentary sources on the archaeological site has been carried out. A journey has been made through the architecture of the intermediate spaces between churches, to understand them beyond their own circulatory use. And placing ourselves decisively on the church of Sant Miquel, a possible correspondence has been established between the architecture and the painting of the apse, from the interpretation of the iconographic program, also of the church of Santa Maria, and with the help of biblical texts. The unit of measurement has been defined based on the measurement of the set and the drawing by means of the 3D modeling of the church of Sant Miquel. And it has been determined what was the first form of the church also of Sant Miquel and its structural performance.Thus, the painting of the apse of St. Michael is, perhaps, a reinterpretation of its architecture, that is, a "plan" made after the construction that represents the rule that was used to think of the church, and where they intervened: the Temple of Ezekiel's vision, the new coming of Jesus, with the representation of the throne of the earthly monarch, and the new heaven and the new earth of the Heavenly Jerusalem.The future line of research will have to insist on two aspects of the same idea: the first, for the understanding of different Christian paintings and mosaics as a tool to represent an architectural composition, following the works of Duval, among others, and doing the iconographic analysis from the different biblical texts; and the second, to find out how this representation corresponded to real architecture, an old but not dethroned idea rehearsed by Krautheimer eighty years ago.Keywords. Seu Episcopal d¿Ègara, Sant Miquel, church, Temple, throne, Ezekiel, cubit, eight.

DOCTORAL DEGREE IN ARCHITECTURE, ENERGY AND ENVIRONMENT

  • ESPINOZA CATERIANO, EDGARD EDUARDO: El recorrido en espacios de baja intensidad lumínica
    Author: ESPINOZA CATERIANO, EDGARD EDUARDO
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN ARCHITECTURE, ENERGY AND ENVIRONMENT
    Department: Department of Architectural Technology (TA)
    Mode: Normal
    Deposit date: 16/06/2022
    Deposit END date: 29/06/2022
    Thesis director: CRESPO CABILLO, ISABEL
    Committee:
         PRESIDENT: ROGORA, ALESSANDRO
         SECRETARI: GARCÍA GIL, MANUEL
         VOCAL: BLANCA GIMÉNEZ, VICENTE
    Thesis abstract: The research focuses on how to illuminate low light intensity spaces. Different uses of those spaces serve as the start point for rethinking lighting design. The characteristics of light, surface and vision are essential to strengthen the link between the symbol and the object's meaning. The present study evaluates the illumination of places destined to reduce the light level without prejudice to the object's vision. Museums are one of those spaces where lighting design should lower light energy for conservation reasons. However, we observe the tendency to maintain high light levels in interior spaces where the purpose of choosing high light intensity is supposed to have a better vision. There are regulations that define the minimum and maximum light levels for workspaces, factories, offices or schools, i.e. the spaces where the requirements assume the condition of high light intensity. In low light intensity spaces, the parameters to consider in the lighting design have a different order of priority than in high light intensity spaces. Lighting intensity alterations produce vision changes and, therefore, changes in the visual perception of the scene. In scotopic vision, we have less ability to distinguish colours, and we get more peripheral vision sensitivity, contrary to photopic vision. Instead, the transition between scotopic and photopic vision, called mesopic vision, is characterized by having the advantages and disadvantages of both types of vision. The changes in the vision lead us to think about searching for different lighting design strategies depending on the light level in the environment.In situations of low light intensity in which the observer is in the scotopic or mesopic vision, the parameters to be considered in the lighting design have a different hierarchy than in high light spaces. In that case, some lighting characteristics become secondary, but the colour temperature becomes the most important component of the lighting design to separate surfaces with similar luminance. This work has analysed such specific cases to establish how much the priorities of a lighting design that develops in these conditions change. It focuses on museums or exhibitions of archaeological heritage, meditation centres, or any other place where a low level of light is required to lead us to a state of calm and concentration. In this study, we find that in mesopic and scotopic vision, when the predominant luminance values are below 10 cd/m2, the luminance contrasts have a shorter value range than in photopic vision, which ranges from 0.1 cd/m2 to 100,000cd/m2. In low light intensity spaces, the chromatic information of the surfaces decreases and the luminance values of the surfaces are very similar to each other. It is necessary to point out three effective strategies in lighting design. The first one is to use the colour temperature to differentiate luminance surfaces with a different meaning for the observer. The second one is to apply the high colour temperature to highlight elements that are foreign to the space but complement the user's visual information. The third one is to avoid light intrusion from the outside or any visual scene with luminance contrasts that exceed the ratio of 1:10. Therefore, we can conclude that in low light intensity spaces, using different light colour temperatures, if associated with different roles played by the surfaces, facilitates visual communication within the space.

DOCTORAL DEGREE IN CIVIL ENGINEERING

  • MOREIRA FILHO, CARLOS AUGUSTO: Finite element simulation of additive manufacturing with enhanced accuracy
    Author: MOREIRA FILHO, CARLOS AUGUSTO
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN CIVIL ENGINEERING
    Department: (DECA)
    Mode: Article-based thesis
    Deposit date: 27/06/2022
    Deposit END date: 08/07/2022
    Thesis director: CERVERA RUIZ, LUIS MIGUEL | CHIUMENTI, MICHELE
    Committee:
         PRESIDENT: SCOVAZZI, GUGLIELMO
         SECRETARI: DIALAMI SHABANKAREH, NARGES
         VOCAL: CARRATURO, MASSIMO
    Thesis abstract: This thesis develops numerical methods to improve the accuracy and computational efficiency ofthe part-scale simulation of Additive Manufacturing (AM) (or 3D printing) metal processes. AM ischaracterized by multiple scales in space and time, as well as multiple complex physics that occurin three-dimensional growing-in-time geometries, making its simulation a remarkable computationalchallenge.To this end, the computational framework is built by addressing four key topics: (1) a Finite Elementtechnology with enhanced stress/strain accuracy including the incompressible limit; (2) an AdaptiveMesh Refinement (AMR) strategy accounting for geometric and solution accuracies; (3) a coarseningcorrection strategy to avoid loss of information in the coarsening AMR procedure, and (4) a GCodebased simulation tool that uses the exact geometric and process parameters data provided to the actual AM machinery.In this context, the mixed displacement/deviatoric-strain/pressure u/e/p FE formulation in (1) isadopted to solve incompressible problems resulting from the isochoric plastic flow in the Von Misescriterion typical of metals. The enhanced stress/strain accuracy of the u/e/p over the standard and u/p FE formulations is verified in a set of numerical benchmarks in iso-thermal and non-isothermal conditions. A multi-criteria AMR strategy in (2) is used to improve computational efficiency while keeping the number of FEs controlled and without the strictness of imposing the commonly adopted 2:1 balance scheme. Avoiding this enables to use high jumps on the refinement level between adjacent FEs; this improves the mesh resolution on the region of interest and keeps the mesh coarse elsewhere.Moving the FE solution from a fine mesh to a coarse mesh introduces loss of information. To prevent this, a coarsening correction strategy presented in (3) restores the fine solution in the coarse mesh, providing computational cost reduction and keeping the accuracy of the fine mesh solution accuracy.Lastly, design flexibility is one of the main advantages of AM over traditional manufacturingprocesses. This flexibility is observed in the design of complex components and the possibility tochange the process parameters, i.e. power input, speed, waiting pauses, among others, throughoutthe process. In (4) a GCode-based simulation tool that replicates the exact path travelled and processparameters delivered to the AM machiney is developed. Furthermore, the GCode-based tool together with the AMR strategy allows to automatically generate an embedded fitted cartesian FE mesh for the evolving domain and removes the challenging task of mesh manipulation by the end-user.The FE framework is built on a high-performance computing environment. This framework enablesto accelerate the process-to-performance understanding and to minimize the number of trial-and-error experiments, two key aspects to exploit the technology in the industrial environment.

DOCTORAL DEGREE IN COMPUTATIONAL AND APPLIED PHYSICS

  • ARCOS GUTIÉRREZ, DAVID: Caracterització optoelectrònica de materials bidimensionals a altes freqüencies
    Author: ARCOS GUTIÉRREZ, 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 COMPUTATIONAL AND APPLIED PHYSICS
    Department: Department of Physics (FIS)
    Mode: Normal
    Deposit date: 16/06/2022
    Deposit END date: 29/06/2022
    Thesis director: AMETLLER CONGOST, LLUIS | FERRER ANGLADA, NURIA
    Committee:
         PRESIDENT: BERTRAN SERRA, ENRIC
         SECRETARI: TOBIAS ROSSELL, GERARD
         VOCAL: ROMEU ROBERT, JORDI
    Thesis abstract: Two-dimensional materials have a lot of applications in the electronic and photonic device design field, especially when they need to be flexible and transparent. In particular, high frequency applications, above 100MHz, are promising because of its unique optoelectronic properties. In addition, due to their low dimensionality, to obtain, handle and characterise the properties of these materials is challenging, especially when several layers of different materials are combined in a single heterostructure. The main objective of this research is to apply and to compare some high-frequency optoelectronic charac-terization techniques on two-dimensional materials. Specifically, graphene, MoS2 and WS2, on different substrates and heterostructures composed by graphene/MoS2 and graphene/WS2 are analysed. Samples of compacted two-dimensional materials, without substrate, such as graphene oxide, reduced graphene oxide and compacted carbon nanotubes (buckypaper) are also analysed. Raman spectroscopy is used in order to ensure the two-dimensionality of the samples and to analyse their structural properties. The surface conductivity of the samples and their transmittance between 200 GHz and 1.5 THz are analysed by terahertz time-domain spectroscopy (THz-TDS) in a transmission setup and also by using a setup based on a Michelson interferometer. A rutile dielectric resonator is used to analyse the surface resis-tance at the resonance frequency, around 10GHz, of compacted materials¿ samples. Finally, FTIR and optical spectroscopies are used to obtain the transmittance of the heterostructures with respect to the individual layers in near-infrared, visible and near-ultraviolet ranges. The values obtained are in good agreement with the nature and composition of the samples and it is confirmed that the techniques are non-destructive and that they allow the extraction of information about quality, optical transmittance and surface conductivity of the conductive and semi-conductive samples. THz-TDS allows performing a measurement of conductivity without electrical contacts in two-dimensional materials and it is sensitive enough to detect differences in similar materials or in heterostructures made by two different layers of materials.
  • SILINI, RICCARDO: Causal inference and forescasting methods for climate data nalysis
    Author: SILINI, RICCARDO
    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: 17/06/2022
    Deposit END date: 01/07/2022
    Thesis director: MASOLLER, CRISTINA | BARREIRO PARRILLO, MARCELO
    Committee:
         PRESIDENT: PÉREZ MUÑUZURI, VICENTE
         SECRETARI: MARTIN GOMEZ, VERONICA
         VOCAL: DONNER, REIK
    Thesis abstract: To advance time series forecasting we need to progress on multiple fronts. In this thesis, we develop algorithms to identify causal relations which allow to identify the driving processes containing useful information for the prediction of the process of interest. Complementing this, machine learning algorithms allow to exploit such information to build data-driven forecast models, and to correct the prediction of dynamical models. The identification from time series analysis of reliable indicators of causal relationships, is essential for many disciplines. Main challenges are distinguishing correlation from causality and discriminating between direct and indirect interactions. Over the years, many methods for data-driven causal inference have been proposed; however, their success largely depends on the characteristics of the system under investigation. Often, their data requirements, computational cost or number of parameters, limit their applicability. In this thesis, we propose a computationally efficient measure for causality testing, with the goal of overcoming the limitations of information-theoretic measures, due their high computational cost. The proposed metric is useful when causality networks need to be inferred from the analysis of a large number of relatively short time series. It can also be very useful for the selection of the inputs for the machine learning algorithms; in fact, it allows to identify those processes which contain useful information for the prediction of a given process. This is particularly useful for systems composed of a large number of processes, whose interactions are poorly understood. On the other hand, the socioeconomic impact of weather extremes draws the attention of researchers to the development of novel methodologies to make more accurate weather predictions. The Madden-Julian Oscillation (MJO), which is the dominant mode of variability in the tropical atmosphere on sub-seasonal time scales, is particularly important because it can promote or enhance extreme events in both, the tropics and the extratropics.Currently, the prediction skill of MJO is receiving a lot of attention, and in this thesis we take two machine learning approaches; first we use machine learning as a stand-alone technique to analyze observed data, showing that two artificial neural networks, a feed-forward neural network and a recurrent neural network, allow a competitive prediction, yet not exceeding the skill of the state-of-art dynamical models. Then, we combine dynamical models with machine learning, which allows to improve the predictions of the best dynamical model. In particular, machine learning allows to improve the prediction of the MJO intensity and geographical localization

DOCTORAL DEGREE IN COMPUTER ARCHITECTURE

  • CALDERÓN TORRES, ALEJANDRO JOSUÉ: Real-time high-performance computing for embedded control systems
    Author: CALDERÓN TORRES, ALEJANDRO JOSUÉ
    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: 17/06/2022
    Deposit END date: 01/07/2022
    Thesis director: KOSMIDIS, LEONIDAS | NICOLÁS RAMÍREZ, CARLOS FERNANDO
    Committee:
         PRESIDENT: MOSHOVOS, ANDREAS
         SECRETARI: PEÑA MONFERRER, ANTONIO JOSE
         VOCAL: DURAK, UMUT
    Thesis abstract: The real-time control systems industry is moving towards the consolidation of multiple computing systems into fewer and more powerful ones, aiming for a reduction in size, weight, and power. The increasing demand for higher performance in other critical domains like autonomous driving has led the industry to recently include embedded GPUs for the implementation of advanced functionalities. The highly parallel architecture of GPUs could also be leveraged in the control systems industry to develop more advanced, energy-efficient, and scalable control systems. However, the closed-source and non-deterministic nature of GPUs complicates the resource provisioning analysis required for the implementation of critical real-time systems. On the other hand, there is no indication of the integration of GPUs in the traditional development cycle of control systems, which is oriented to the use of a model-based design approach. Recently, some model-based design tools vendors have extended their development frameworks with GPU code generation capabilities targeting hybrid computing platforms, so that the model-based design environment now enables the concurrent analysis of more complex and diverse functions by simulation and automating the deployment to the final target. However, there is no indication whether these tools are well-suited for the design and development of time-sensitive systems.Motivated by these challenges, in this thesis, we contribute to the state of the art of real-time control systems towards the adoption of embedded GPUs by providing tools to facilitate the resource provisioning analysis and the integration in the model-based design development cycle. First, we present a methodology and an automated tool to extract the properties of GPU memory allocators. This tool allows the computation of the real amount of memory used by GPU applications, facilitating a correct resource provisioning analysis. Then, we present a library which allows the characterization of the use of dynamic memory in GPU applications. We use this library to characterize GPU benchmarks and we identify memory allocation patterns that could be modified to improve performance and memory consumption when targeting embedded GPUs. Based on these results, we present a tool to optimize the use of dynamic memory in legacy GPU applications executed on embedded platforms. This tool allows us to minimize the memory consumption and memory management overhead of GPU applications without rewriting them. Afterwards, we analyze the timing of control algorithms executed in embedded GPUs and we identify techniques to achieve an acceptable real-time behavior. Finally, we evaluate model-based design tools in terms of integration with GPU hardware and GPU code generation, and we propose improvements for the model-based generated GPU code. Then, we present a source-to-source transformation tool to automatically apply the proposed improvements.
  • MAHDAVI, KAVEH: Enhanced clustering analysis pipeline for performance analysis of parallel applications
    Author: MAHDAVI, KAVEH
    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: 22/06/2022
    Deposit END date: 06/07/2022
    Thesis director: LABARTA MANCHO, JESUS JOSE
    Committee:
         PRESIDENT: MILLER, BARTON
         SECRETARI: AYGUADÉ PARRA, EDUARD
         VOCAL NO PRESENCIAL: LARRAÑAGA MÚGICA, PEDRO
    Thesis abstract: Clustering analysis is widely used to stratify data in the same cluster when they are similar according to the specific metrics. We can use the cluster analysis to group the CPU burst of a parallel application, and the regions on each process in-betweencommunication calls or calls to the parallel runtime. The resulting clusters obtained are the different computational trends or phases that appear in the application. These clusters are useful to understand the behavior of the computation part of theapplication and focus the analyses on those that present performance issues.Although density-based clustering algorithms are a powerful and efficient tool to summarize this type of information, their traditional user-guided clustering methodology has many shortcomings and deficiencies in dealing with the complexity of data,the diversity of data structures, high-dimensionality of data, and the dramatic increase in the amount of data. Consequently, the majority of DBSCAN-like algorithms have weaknesses to handle high-dimensionality and/or Multi-density data, and they are sensitive to their hyper-parameter configuration. Furthermore, extracting insight from the obtained clusters is an intuitive andmanual task. To mitigate these weaknesses, we have proposed a new unified approach to replace the user-guided clustering with anautomated clustering analysis pipeline, called Enhanced Cluster Identification and Interpretation (ECII) pipeline. To build the pipeline, we propose novel techniques including Robust Independent Feature Selection, Feature Space Curvature Map, Organization Component Analysis, and hyper-parameters tuning to feature selection, density homogenization, clusterinterpretation, and model selection which are the main components of our machine learning pipeline. This thesis contributes four new techniques to the Machine Learning field with a particular use case in Performance Analytics field.The first contribution is a novel unsupervised approach for feature selection on noisy data, called Robust Independent Feature Selection (RIFS). Specifically, we choose a feature subset that contains most of the underlying information, using the samecriteria as the Independent component analysis. Simultaneously, the noise is separated as an independent component.The second contribution of the thesis is a parametric multilinear transformation method to homogenize cluster densities while preserving the topological structure of the dataset, called Feature Space Curvature Map (FSCM). We present a new GravitationalSelf-organizing Map to model the feature space curvature by plugging the concepts of gravity and fabric of space into the Self-organizing Map algorithm to mathematically describe the density structure of the data. To homogenize the cluster density, we introduce a novel mapping mechanism to project the data from the non-Euclidean curved space to a new Euclidean flatspace.The third contribution is a novel topological-based method to study potentially complex high-dimensional categorized data by quantifying their shapes and extracting fine-grain insights from them to interpret the clustering result. We introduce ourOrganization Component Analysis (OCA) method for the automatic arbitrary cluster-shape study without an assumption about the data distribution.Finally, to tune the DBSCAN hyper-parameters, we propose a new tuning mechanism by combining techniques from machine learning and optimization domains, and we embed it in the ECII pipeline.Using this cluster analysis pipeline with the CPU burst data of a parallel application, we provide the developer/analyst with a high-quality SPMD computation structure detection with the added value that reflects the fine grain of the computation regions.

DOCTORAL DEGREE IN ENVIRONMENTAL ENGINEERING

  • MUÑOZ LIESA, JOAN: Energy and material circularity in building-integrated agriculture: an environmental approach
    Author: MUÑOZ LIESA, JOAN
    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: Temporary seizure
    Deposit date: 16/06/2022
    Deposit END date: 29/06/2022
    Thesis director: GASSO DOMINGO, SANTIAGO | CUERVA CONTRERAS, EVA
    Committee:
         PRESIDENT: MONTERO CAMACHO, JUAN IGNACIO
         SECRETARI: MACARULLA MARTÍ, MARCEL
         VOCAL NO PRESENCIAL: VAZQUEZ, IAN
    Thesis abstract: Cities are great resource consumers and largely contribute to anthropogenic environmental impacts, urgently requiring a decarbonization plan. Urban agriculture lies on industrial ecology principles; waste resources from cities are used as feedstock for crop production and vice versa through building-integrated agriculture (BIA) infrastructures. This thesis aimed to analyze environmental, material, and energy flows in BIA from an industrial ecology perspective, ensuring circular economy strategies align with improved environmental performance. We based our assessments on an integrated rooftop greenhouse (iRTG) case study, and we separately analyzed the environmental benefits of BIA resulting from (i) improving structural material resource-use; (ii) quantifying the energy co-benefits and (iii) realizing BIA multifunctionality that can further cut-off environmental impacts among all BIA co-products. A material assessment revealed the iRTG structure is responsible for 67.3% of environmental impacts. Three key design factors were identified as main causes of steel structural needs compared to conventional greenhouses: rooftop height, urban environment, and ventilation design. When optimized, impacts were reduced by 24.1%, demonstrating urban greenhouses do not imply greater amounts of structural materials per se compared to soil-based greenhouses. Rather, iRTGs can benefit from the urban environment, and compensate additional steel amounts with optimized designs. Up to 45.9% of environmental impacts were caused by the iRTG covering material; decaying optical properties and building shadows reduced between 36.2-50.2% the incoming solar radiation. By assessing the effects of a 4mm-antireflective glass, average lifetime solar gains increased up to 20.5% and tomato yields up to 46.6%, which reduced environmental impacts by 33.9%. An ETFE film produced less tomato yields (19.2±2.3 kg/m2) but reduced impacts by 41.1%. Overall, we demonstrate the importance of employing integrated and life-cycle perspectives to considering all side-effects of BIA. Energy circularity in an iRTG operating with active or passive ventilation strategies was modelled to quantify energy savings. Passive heat from the building to the greenhouse resulted in 342 kWh/m2·year of harvested building waste heat (84% occurring during nighttime). Moreover, the iRTG insulation effect provided 120 kWh/m2y of thermal savings to the building. When considering the operating energy costs, 444 kWh/m2y of net thermal gains were obtained. Excess solar energy was harvested by means of active ventilation strategies and resulted in 205 kWh/m2y of thermal heat (1.59 ac/h). Similarly, 198 kWh/m2y of low-grade thermal energy from building exhaust air were harvested in the iRTG. Overall, active ventilation strategies resulted in 404 kWh/m2y of energy savings, which doubles the amount of energy saved with a passive iRTG configuration. We then compared energy gains with material energy costs of passive and active iRTG configurations. In line with other energy saving strategies, energy payback times of both configurations were 3.52 (passive) and 2.20 (active) years. Thus, despite active strategies require additional energy and operating costs, greater benefits can be obtained. By aggregating all environmental improvements at the functional level (kg of tomato), we found a 43.2% reduction in environmental impacts compared to the current ICTA-iRTG infrastructure. Environmental impacts were then allocated to all coproducts using their economic value, further reducing these impacts by 60.7%, while environmental costs per kWh were equivalent to those from other renewable energy systems. With this dissertation, we therefore demonstrate that by designing iRTG infrastructures that enhance and optimize the exchange of resources with the built environment, it is possible to avoid wasting resources and retain their value to pave the way towards an effective and sustainable circular economy.

DOCTORAL DEGREE IN NETWORK ENGINEERING

  • KIBALYA, GODFREY MIRONDO: Contribution to Multi-domain Network Slicing: Resource Orchestration Framework and Algorithms
    Author: KIBALYA, GODFREY MIRONDO
    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 NETWORK ENGINEERING
    Department: Department of Network Engineering (ENTEL)
    Mode: Normal
    Deposit date: 20/06/2022
    Deposit END date: 04/07/2022
    Thesis director: SERRAT FERNANDEZ, JUAN | GORRICHO MORENO, JUAN LUIS
    Committee:
         PRESIDENT: BALIOSIAN, JAVIER ERNESTO
         SECRETARI: HESSELBACH SERRA, XAVIER
         VOCAL: ROTHENBERG, CHRISTIAN ESTEVE
    Thesis abstract: 5G/6G services and applications, in the context of the eMBB, mMTC and uRLLC network slicing framework, whose network infrastructure requirements may span beyond the coverage area of a single Infrastructure Provider (InP), are envisaged to be supported by leasing resources from multiple InPs. A challenging aspect for a Service Provider (SP) is how to obtain an optimal set of InPs on which to provision the requests and the particular substrate nodes and links within each InP on which to map the different VNFs and virtual links of the service requests, respectively, for a seamless, reliable and cost-effective orchestration of service requests.Existing works in this area either perform service mapping in uncoordinated manner, do not incorporate service reliability or do so from the perspective of stateless VNFs. Also they assume full information disclosure, or are based on exact approaches, which considerations are not well suited for future network scenarios characterized by delay sensitive mission critical applications and resource constrained networks. This thesis contributes to the above challenge by breaking the multi-domain service orchestration problem into two interlinked sub-problems that are solved in a coordinated manner: (1) Request splitting/partitioning (sub-problem 1), involving obtaining a subset of InPs and the corresponding inter-domain links on which to provision the different VNFs and virtual links of the service request; (2) Intra-domain VNF orchestration (sub-problem 2), involving obtaining the intra-domain nodes and links to provision the VNFs and virtual links of the sub-SFC associated with each InP. In this way, the thesis sets out four key targets that are necessary to align with the mission critical and delay sensitive use-cases envisaged in 5G and future networks in terms of service deployment cost and QoS: (1) coordinated mapping of service requests, with a view of realizing better utilization of the substrate resources; (2) survivability and fault-tolerant orchestration of service requests, to tame both QoS violations and the penalties from such violations; (3) limited disclosure of InP internal information, in order adhere to the privacy requirements InPs, and (4) achieving all the above targets in polynomial time. In order to realize the above targets, the thesis sought for solution techniques that are: (1) able to incorporate information learned in the previous solutions search space and historical mapping decisions, hence, resulting in acceptable performance even in scenarios of limited information exposure and fuzzy environments; (2) robust and less problem specific, hence, can be tailored to different optimization objectives, network topologies and service request constraints, thus enabling to deal with requests with either chained topologies or with bifurcated paths; (3) capable of dealing with an optimization problem that is jointly affected by multiple attributes, since in practice, the service deployment cost is jointly affected by multiple conflicting costs; (4) able to realize near-optimal solutions in practical run-times, thus rendering well suited approaches for delay sensitive and resource constrained scenarios.Three different algorithms namely, an RL, Genetic Algorithm (GA) and a fully distributed multi-stage graph-based algorithms are proposed for sub-problem 1. In addition, five different algorithms based on GA, Harmony search, RL, and multi-stage graph approach are proposed for sub-problem 2. Finally, in order to guide the implementation and adherence of the thesis proposals to the four main targets of the thesis, an architectural framework is proposed, aligned with the ETSI NFV-MANO architectural framework. Overall, the simulations results proved that the thesis proposals are optimized in terms of request acceptance ratios, mapping cost and execution time, hence, rendering such proposals well suited for 5G and future scenarios.

DOCTORAL DEGREE IN PHOTONICS

  • OLIVEIRA DE ALMEIDA, JESSICA: Quantum Optics at its best: from quantum interferometry to quantum metrology
    Author: OLIVEIRA DE ALMEIDA, JESSICA
    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: 22/06/2022
    Deposit END date: 06/07/2022
    Thesis director: LEWENSTEIN, MACIEJ | SKOTEINOTIS, MICHALIS
    Committee:
         PRESIDENT: SANCHEZ SOTO, LUIS LORENZO
         SECRETARI: GESSNER, MANUEL
         VOCAL: PARNIAK-NIEDOJADLO, MICHAL PAWEL
    Thesis abstract: Quantum optics experiments are currently the most advanced techniques to under- stand, verify and simulate quantum phenomena. However, to access all the perfor- mance available in quantum states of light, one needs to address fundamental opera- tional limits. In quantum mechanics, the measurement strategy affects the quantum state; therefore, to access all the degrees of freedom available in the quantum states, one must implement the optimal feasible measurement. In this thesis, I investigate how to perform more precise measurements in optics, namely slit-interference and image resolution, by exploiting the quantum mechanical nature of light. A complete description of multi-slit interference must include nonclassical paths, Feyn- man paths that goes through two or more slits. Prior work with atomic interference in the double-slit experiment with cavities as which-way detectors, has shown these paths to be experimentally inaccessible. In this thesis I show how such a setup can detect nonclassical paths with 1% probability, if different nonclassical paths are in- cluded. I also show how this setup can be used to erase and restore the coherence of the nonclassical paths. In the same chapter I demonstrate how the same setup could implement an exact measure of Born-rule violation. And in the last part I debate about the figures of merit in the literature to test the Born-rule. During more than one century, there was a fundamental limit on image resolution; due to diffraction effects in finite detectors apertures, one cannot resolve two incoher- ent sources very close to each other, e.g. stars. In the last decade, the formalism of quantum information allowed new proposals for sub-diffraction limited resolution or super-resolving measurements. Nevertheless, these measurements are susceptible to misalignment. In this thesis, I suggest alternative measurement strategies to incorpo- rate misalignment in super-resolution imaging, showing that sub-diffraction limited resolution is still possible. The proposed measurements can be implemented using linear optical transformations and offer an advantage in the case of estimation and discrimination of two incoherent point sources allowing one to quantify the mitigat- ing effects of misalignment. Moreover, I propose a collective measurement strategy, on two or more photons, that estimates the separation between two incoherent point sources and is oblivious to misalignment. In an optics experiment, the quantum state verification relies on tomography measure- ments on copies of the prepared state. The error in tomography experiments is called confidence region, and it defines the region in which the quantum state is found with the desired probability. There are different methods to compute confidence regions; in this thesis, I analyze the capability of the known methods by resolving two nearby quantum states using a finite amount of measurement data.
  • SANCHEZ, AURELIEN: Laser-induced electron interferences from atoms and molecules
    Author: SANCHEZ, AURELIEN
    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: 20/06/2022
    Deposit END date: 04/07/2022
    Thesis director: BIEGERT, JENS
    Committee:
         PRESIDENT: SENFTLEBEN, ARNE
         SECRETARI: LEWENSTEIN, MACIEJ
         VOCAL: FIGUEIRA DE MORISSON FARIA, CARLA
    Thesis abstract: Since discovering wave-particle duality, science has changed our perception of light and matter, especially at the subatomic level. Thanks to such discoveries, we have been able to develop and expand our scientific knowledge over the past two centuries, crossing those limits. For instance, let us take the famous double-slit experiment from T. Young (1801). This experiment has been extended after the twentieth-century quantum revolution, revealing electron and neutron diffraction used nowadays to measure the nuclei separation from complex structures. Similarly, the experiment of Michelson and Morley (1887), which follows T. Young foundations, got a fair success in astronomy, enabling high-resolution imaging of stars in the universe. In this thesis, we use light to generate electrons and produce interferences similar to the double-slit experiment, which is analyzed further to study the atomic properties.On the dynamics of an atom, that is, attoscience, we use ultrafast laser pulses to trigger motions on a femtoseconds time-scale.Together with the use of strong intense laser fields in the Mid-IR regime, the electron is ionized with zero-kinetic energy and subsequently accelerated by the laser ponderomotive energy.Strong field dynamics offer rich structures that are encoded in the photoelectron momentum distribution. Since we use two-color combined laser fields, we can gate and control those dynamics further down on the sub-cycle scale. More precisely, we show that with the help of a Reaction Microscope, we can extract both electron information and nuclear dynamics within extraordinary sub-cycle temporal resolution.Finally, the strong-field recollision model is investigated with molecules through the previously developed laser-induced electron diffraction (LIED) method. We show that backscattered electron interferences, issued from strong field at low impact parameters, embedded a particular molecular orientation that can be reproduced when the molecule is considered aligned with the laser field polarization. Those findings seem to encode a more profound property about wave diffraction in molecules until recently unexplored due to the imposed conditions given in conventional electron diffraction (CED).

DOCTORAL DEGREE IN SUSTAINABILITY

  • LÓPEZ DÍAZ, MARÍA TERESA DE JESÚS: Contextualización de la enseñanza de las matemáticas en las carreras tecnológicas
    Author: LÓPEZ DÍAZ, MARÍA TERESA DE JESÚS
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN SUSTAINABILITY
    Department: University Research Institute for Sustainability Science and Technology (IS.UPC)
    Mode: Article-based thesis
    Deposit date: 21/06/2022
    Deposit END date: 05/07/2022
    Thesis director: PEÑA CARRERA, MARTA
    Committee:
         PRESIDENT: MAS MARÍ, JOSÉ
         SECRETARI: RODELLAR BENEDE, JOSE JULIAN
         VOCAL NO PRESENCIAL: DE TERÁN DE VERGARA, FERNANDO
    Thesis abstract: The teaching of Mathematics has been always a matter of great concern at all academic levels and more especially in technological degrees. Both the contents of mathematical subjects and the way they are taught, have been always questioned. Currently, students have less interest in technological degrees and the dropout rate has increased in first courses of these studies. One of the main reasons is the lack of motivation that students have towards mathematical subjects in these first academic years, which is derived in most cases, from the lack of awareness about the importance of Mathematics for their academic progress and for their future profession. Likewise, technological knowledge is becoming more specialized, as well as fundamental for economic development of present societies, thus experts in STEM (Science, Technology, Engineering, Mathematics) disciplines are more required and the occupation demand of STEM professionals is expected to increase. The fact that there are fewer students interested in technological degrees and that these specialists are the most demanded, accentuate the concern of educators and professionals involved. The main objective of this thesis is to increase students¿ motivation and involvement towards mathematical subjects in first academic years of technological degrees through the contextualization of these subjects in the different disciplines which compose their degrees, so that students became aware of the importance of Mathematics for the development of their degree and for their future career. In this way, students¿ interest towards Mathematics increase, growing their academic performance and decreasing the dropout failure rate in these degrees. So, this work has as a goal, the improvement of the quality education in technological degrees, in which the required knowledge for the education in sustainable development is taught, and therefore it contributes to the achievement of the SDG (Sustainable Development Goals) proposed by Unesco (United Nations Educational, Scientific and Cultural Organization) in the 2030 Agenda. To attain these objectives, the implementation of practical mathematical applications related to the disciplines that students will learn in next academic years, have been undertaken. To this end, in the 2019/2020 y 2020/2021 academic years, the seminars ¿Applications of Mathematics in Engineering I: Linear Algebra¿, and ¿Applications of Mathematics in Engineering II: Multivariable Calculus¿, in UPC (Universitat Politècnica de Catalunya-BarcelonaTech), based on the teaching of these subjects through the execution of real problems, where the mathematical concepts which are part of those subjects, are necessary to solve the problems. To analyze the effect that these seminars have caused on the students, anonymous surveys has been held, where students have valued these sessions regarding to their motivation improvement and to the learning of mathematical concepts through practical applications. Moreover, at the end of each seminar, personal interviews have been undertaken, in which students have been able to express straightforwardly their opinion about these sessions. The results obtained confirm that the implementation of real mathematical problems increases their motivation and improves the learning of the developed mathematical concepts, what implies a performance increase and a dropout rate decrease in first academic years of technological degrees. This entails a greater interest in STEM degrees, which are essential for economic development of present societies.

Last update: 29/06/2022 04:30:20.