Doctoral School

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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 AGRI-FOOD TECHNOLOGY AND BIOTECHNOLOGY

  • VÁSQUEZ CASTILLO, FLOR DE MARÍA: Crioconcentración en Bloque para Jugo de Granada (Punica granatum L.)
    Author: VÁSQUEZ CASTILLO, FLOR DE MARÍA
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN AGRI-FOOD TECHNOLOGY AND BIOTECHNOLOGY
    Department: Department of Agri-Food Engineering and Biotechnology (DEAB)
    Mode: Normal
    Deposit date: 19/07/2024
    Deposit END date: 02/09/2024
    Thesis director: HERNANDEZ YAÑEZ, EDUARDO | ACHAERANDIO PUENTE, MARIA ISABEL
    Committee:
         PRESIDENT: IBARZ RIBAS, ALBERT
         SECRETARI: DANTAS, ADRIANA
         VOCAL: FERRANDO COGOLLOS, M. MONTSERRAT
    Thesis abstract: One of the food industry's pressing global challenges is ensuring food security for a rapidly growing population. The enormous problems of water scarcity, climate change and high energy costs are barriers to achieving this crucial goal. This and the preferences of modern consumers who prioritize healthy and affordable foods have stimulated researchers to develop technologies that preserve bioactive components and defend environmental sustainability.The pomegranate is a fruit of high nutritional value due to its bioactive compounds. Pomegranate juice (PJ) is widely consumed for its pleasant flavor and health-promoting properties. There are different varieties of pomegranate. The 'Wonderful' variety is the most consumed due to its organoleptic characteristics and excellent antioxidant activity. A growing sector in the food industry is the production of fruit juice concentrates. Fruit juices mostly contain between 8% and 16% w/w total soluble solids, are expensive to package, store for long periods, and transport over long distances. Therefore, removing some or all of the water from such liquids is desirable. Fruit juice concentrates are valuable semi-finished products for the production of fruit juices, beverages, etc., as they provide microbiological stability and allow economy in the packaging, transportation, and distribution of the product.Cryoconcentration is an environmentally friendly technique, with which a high-quality concentrate is obtained because the process occurs at low temperatures, which helps preserve the bioactive components of the juice. Additionally, the content of water. Among the different cryoconcentration techniques, block cryoconcentration stands out for its simplicity and good results. However, the research carried out so far has used several stages to improve these parameters, especially solute recovery (SY).This thesis aims to obtain a single-stage block cryoconcentration process for pomegranate juice, aiming to improve the SY and, therefore, the concentration of its bioactive components.First, the vacuum-assisted block cryoconcentration (VABC) method was compared with the centrifugation-assisted block cryoconcentration (CABC) method. In these tests carried out at short times, moderate concentration indexes (CI) were obtained, with the SY being better in the CABC method than in the VABC, but lower than 60%.With our sights set on the objective, the V-CABC method was tested, a combination of the centrifugation and vacuum method, improving the IC to 3.8 and SY close to 70%. Additionally, the total phenolic compounds (TPC) of the concentrates were quantified, which increased up to almost 5 times compared to the initial sample.Finally, the block cryoconcentration method assisted by centrifugation and filtration (F-CABC) was used, achieving a moderate IC (3.2), and a high SY, close to 90%. In addition, it was possible to concentrate more than 3 times the bioactive compounds and 2 times the antioxidant capacity.The research carried out in this thesis provides crucial knowledge for the fruit juice sector, especially pomegranate juice concentrates, and for scientists specialized in cryoconcentration. The results obtained can guide the design of products based on pomegranate juice concentrate, cryoconcentration processes,and equipment to promote the expansion of this sector. In general, if it wants to obtain a high SY and efficiency (Eff) with a moderate CI and TPC concentration index (TPCI), the F-CABC technique is recommended. On the other hand, to obtain higher CI and TPCI, as well as moderate SY, the V-CABC method is recommended.

DOCTORAL DEGREE IN ARCHITECTURAL, BUILDING CONSTRUCTION AND URBANISM TECHNOLOGY

  • BERIGUETE ALCÁNTARA, FANNY ESTHER: Participación del tejido social en el espacio urbano: Aproximación a un sistema de indicadores para la evaluación de la sostenibilidad de iniciativas ciudadanas
    Author: BERIGUETE ALCÁNTARA, FANNY ESTHER
    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: 26/07/2024
    Deposit END date: 09/09/2024
    Thesis director: RODRIGUEZ CANTALAPIEDRA, INMACULADA | PALUMBO FERNANDEZ, MARIANA
    Committee:
         PRESIDENT: ROCA BLANCH, ESTANISLAO
         SECRETARI: SIMÓ I SOLSONA, MONTSERRAT
         VOCAL: ASPRILLA LARA, YEFER
    Thesis abstract: In recent years, citizen participation has emerged as a fundamental pillar in building sustainable cities. This research addresses this phenomenon, focusing on the evaluation of Citizen Initiatives (CIs). The main objective is to develop a homogeneous system of indicators to comprehensively measure the impact of these initiatives in the three areas of sustainability, which include social, economic and environmental aspects, thus contributing to the creation of a more complete urban model and highlighting the importance of the active participation of the social fabric in the urban space. The methodology adopted follows a continuous improvement approach, and includes an initial documentary exploration, a review of existing assessment systems, the design of the tool, validation through experts and case studies, and finally, the elaboration of an improved proposal of the assessment system. The result is an improved assessment system designed to measure the contribution of CIs to improving the sustainability of a neighbourhood or urban environment. The innovation lies in the inclusion of the spatial dimension and the adaptability for self-assessments of CIs, as current systems only focus on environmental, economic and, on a smaller scale, social aspects, without taking into account the spatial component. This spiral methodology allows for continuous improvement of the proposal, ensuring its relevance and quality. The research contributes not only to the theoretical understanding of the relationship between citizen participation and sustainability, but also offers a practical tool to evaluate and promote the role of initiatives in improving the sustainability of cities from a holistic perspective.
  • HUANG, DAWEI: Influence of interfacial bonding behavior on the compressive performance of sprayed mortar reinforced masonry walls
    Author: HUANG, DAWEI
    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: Article-based thesis
    Deposit date: 18/07/2024
    Deposit END date: 31/07/2024
    Thesis director: ALBAREDA VALLS, ALBERT | PONS VALLADARES, ORIOL
    Committee:
         PRESIDENT: ÜSTÜNDAG, CENK
         SECRETARI: CORNADÓ BARDÓN, CÒSSIMA
         VOCAL NO PRESENCIAL: LIU, PENG
    Thesis abstract: This thesis investigates the adhesion behavior between sprayed mortar and masonry substrates, focusing on the influence of compressive strength, mortar age, and surface roughness on adhesion strength. Through detailed experiments and comprehensive analysis, it seeks to better understand these factors and their impact on rehabilitation techniques for masonry structures. The results of this investigation not only expand theoretical knowledge about the adhesion behavior between mortar and masonry but also provide practical recommendations to improve the durability and effectiveness of retrofitting interventions.Experiments were conducted on samples with different compressive strengths (15 MPa, 30 MPa, and 45 MPa) to assess how these factors affect both tensile and shear adhesion strength. It was observed that the tensile adhesion strength decreases with increasing compressive strength of the masonry due to the brittle nature of high-strength materials. Specifically, masonry with a compressive strength of 15 MPa showed tensile adhesion strength ranging from 0.2 to 1 MPa, while masonry with a compressive strength of 40 MPa showed values concentrated between 0 and 0.1 MPa. This behavior is due to the fact that high-strength masonry tends to fail more abruptly, reducing its capacity to maintain adhesions under tension.On the other hand, the shear adhesion strength showed a positive correlation with compressive strength. Substrates with higher compressive strength provided greater shear capacity due to better mechanical interlocking facilitated by surface roughness. Experimental results demonstrated that the shear adhesion strength was almost double that of the tensile strength, highlighting the importance of surface texture in adhesion performance.The age of the mortar is also a crucial factor. Tests were conducted at 7 and 28 days to evaluate the development of adhesion strength over time. At 7 days, the adhesion strength was relatively low due to the ongoing hydration process and incomplete development of the mortar's mechanical properties. However, at 28 days, the adhesion strength increased significantly as the mortar achieved higher levels of hydration and improved mechanical properties. This underscores the importance of allowing adequate curing time in practical applications to ensure the longevity and effectiveness of reinforced structures.Surface roughness is a determining factor in adhesion strength. We measured roughness using the Joint Roughness Coefficient (JRC) and the arithmetic mean deviation (Ra) to quantify its impact. It was found that rougher surfaces facilitated better mechanical interlocking, improving adhesion strength. This finding highlights the importance of surface preparation in rehabilitation applications, where increasing the substrate's roughness can significantly enhance adhesion performance.The experiments revealed three typical modes of failure: adhesion disconnection, specimen fracture, and adhesion material fracture. Adhesion disconnection occurred when the adhesion strength was weaker than the individual strengths of the mortar and masonry, resulting in a clean separation at the interface without significant damage. Specimen fracture was mainly observed in samples with a fragile surface layer developed during mortar curing. Adhesion material fracture involved the rupture of the adhesion material itself, highlighting the impact of shear stress on adhesion integrity.

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

  • PÉREZ SANDOVAL, MIGUEL ÁNGEL: Integración de BIM en la educación arquitectónica: Impacto del aprendizaje basado en proyectos y equipos distribuidos globalmente
    Author: PÉREZ SANDOVAL, MIGUEL ÁNGEL
    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: Departamento de Representación Arquitectónica (RA)
    Mode: Normal
    Deposit date: 26/07/2024
    Deposit END date: 09/09/2024
    Thesis director: VALLS DALMAU, FRANCISCO | NAVARRO DELGADO, ISIDRO
    Committee:
         PRESIDENT: MINAYA HERNANDEZ, FERNANDO RAFAEL
         SECRETARI: REDONDO DOMINGUEZ, ERNEST
         VOCAL NO PRESENCIAL: FONSECA ESCUDERO, DAVID
    Thesis abstract: This doctoral thesis delves into the user experience of the Building Information Modeling (BIM) methodology in architectural pedagogy, through four in-depth case studies. This research proposes an educational innovation approach that integrates the BIM methodology in interuniversity workshops implementing Globally Distributed Teams (GDT) and the Project Based Learning (PBL) approach, with the objective of improving the educational experience and training students for effective collaboration in Architecture. Engineering and Construction Industry (AEC).The interuniversity workshops were held with the participation of students and professors from prestigious architecture schools in Mexico and Spain: the Metropolitan Autonomous University of Azcapotzalco (UAM-Azc), the Barcelona Higher Technical School of Architecture (ETSAB) and the Higher Technical School of La Salle. Architecture (URL). Likewise, other renowned institutions such as the University of Guadalajara (UdeG) and the Universitat Politècnica de València (UPV) were integrated.For four consecutive years, participants tackled social facility design challenges, including a First Contact Family Clinic (2020), a Cultural Center (2021), an Intermediate Therapy Center for COVID-19 (2022), and a Refugee Camp . , Ukraine Crisis (2023).The research employed a mixed methodological approach that combined quantitative analysis of data collected through surveys with qualitative analysis of data derived from interviews and participant observation. With this approach, this research demonstrates that it improves the user experience through collaboration and exchange between students located in distant geographical locations, while seeking to identify best practices in the use of BIM to enrich the training of future architects. in the AEC industry. It is projected that the findings of these interuniversity workshops with GDT and PBL will be very useful for both educational institutions as a methodological example.

DOCTORAL DEGREE IN BUSINESS ADMINISTRATION AND MANAGEMENT

  • HURTADO ILLANES, MARISOL CAROL: Diseño de un Modelo Integrado para el Empoderamiento Individual y el Apoyo Social en la Gestión del Conocimiento de Enfermedades Crónicas
    Author: HURTADO ILLANES, MARISOL CAROL
    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: 17/07/2024
    Deposit END date: 30/07/2024
    Thesis director: VIEDMA MARTI, JOSE M. | COLL BERTRAN, JOSEP
    Committee:
         PRESIDENT: CANALS PARERA, AGUSTI
         SECRETARI: BARTOLOME COMAS, ROSA MARIA
         VOCAL: SERRADELL LÓPEZ, ENRIC
    Thesis abstract: This transdisciplinary research focuses on knowledge management and human capital development in the context of chronic diseases, investigating mechanisms of empowerment in virtual communities. Living with a chronic illness involves facing high uncertainty and stress, resulting in social limitations and challenges. However, health conditions do not alter the essence of the individual or their need to actively participate in society. Chronic diseases increase global morbidity and mortality, representing a significant economic burden for healthcare systems. In this context, individual and community empowerment is crucial to improving the well-being and quality of life of patients.The study develops an Integrated Model for Individual Empowerment and Social Support in the Knowledge Management of Chronic Diseases, aimed at improving quality of life and enhancing patient autonomy. Its objectives include analyzing the influence of individual empowerment on patient engagement, exploring the connection between individual empowerment and community development in virtual communities, and examining the impact of sustainable practices on long-term empowerment. Using a mixed methodology that combines Dubin's methodology for theoretical development, the TDR approach (Transdisciplinary Research), and qualitative methods, the model was validated in a virtual community of chronic patients.The model focuses on key aspects such as Individual Empowerment (IE), Active Participation (IEG), Community Development (CD), and Sustainable Practices (SP). Furthermore, it describes states ranging from initial levels of low empowerment to achieving complete autonomy and commitment, through the formulation of theoretical propositions and the identification of intermediate stages that connect these elements and describe their interrelationships.Self-efficacy was manifested in narratives and testimonies that revealed participants' confidence and control. Active participation was evidenced in contributions and community activities, demonstrating a commitment to self-care. Social support was detected in interactions, reflecting solidarity and collaboration. Collaboration was observed in teamwork and mutual aid. Community development became evident through practices aimed at collective well-being. Access to knowledge was manifested in participation and resource-seeking, while sustainable practices were identified in actions aimed at long-term positive change.The results revealed individual strengthening among members of the online support group, highlighting the sense of personal control and resilience fostered through emotional support and self-efficacy. Members of the virtual community showed adaptability in facing health challenges through innovative strategies and community support, resulting in significant improvements in lifestyle habits and well-being. These aspects underscore the crucial influence of online support in promoting self-care, resilience, and overall health.In conclusion, the research highlights that empowerment through virtual communities is fundamental for the effective management of chronic diseases, emphasizing the importance of a holistic approach that encompasses social, psychological, and health self-management support. These findings enrich existing knowledge and influence health decisions and policies, underscoring the need to integrate sustainable practices into health policies for general well-being. The unified model of individual and community empowerment shows potential for application in other aspects of personal development, focusing on human capital and knowledge management.

DOCTORAL DEGREE IN CIVIL ENGINEERING

  • SILVA CANCINO, NATHALIA: Evaluation of potential hazard due to off-stream reservoir failure using Machine Learning techniques
    Author: SILVA CANCINO, NATHALIA
    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: Barcelona School of Civil Engineering (ETSECCPB)
    Mode: Article-based thesis
    Deposit date: 22/07/2024
    Deposit END date: 04/09/2024
    Thesis director: BLADE CASTELLET, ERNEST | SALAZAR GONZÁLEZ, FERNANDO
    Thesis abstract: Hazard classification for dams and off-stream reservoirs, which entails identifying potential damages in the event of structural failure, is a crucial tool for implementing local-level risk reduction plans. Consequently, national administrations have developed guidelines including suggested methodologies and tools.The modification of the Spanish Regulation of the Public Hydraulic Domain (Royal Decree 849/1986, of April 11), carried out through Royal Decree 9/2008, of January 11, obliges owners of off-stream reservoirs with a height of 5 meters or a capacity higher than 100,000 m3, whether public or private, to develop a classification study based on the potential risk of their failure (Articles 356 and 367). This represented a significant paradigm shift, under the former regulation, such a study was only required for dams exceeding 15 m in height or those with a height between 10 and 15 m and a capacity exceeding 100,000 m3.The procedure for this classification is time and resource-consuming, and in the specific case of owners of off-stream reservoirs, they may not have these assets. Therefore, this research proposes a simplified methodology to classify off-stream reservoirs, utilizing a surrogate Machine Learning (ML) model that is simpler and has a lower computational cost than conventional approaches. Additionally, the influence of two sources of uncertainties on hazard classification is analysed. This research is based on the generation of synthetic data. A specialized tool in Iber was developed to generate massive 2D hydraulic models of synthetic off-stream reservoir failures, which make all the processes of construction, calculation and extraction of results automatic.The first analysis was focused on the effect of selecting a breach parametric model on the hydraulic variables, the potential damages, and the hazard classification of the structures. Three common parametric models were compared, using a set of synthetic cases and a real off-stream reservoir. The results highlighted that the choice of the model has significant effects. Notably, the erodibility of the material exerts a high influence, surpassing that of the failure mode. The use of an inappropriate model or a lack of information regarding dike material can lead to overly conservative or underestimated results, consequently affecting hazard classification.The ML model constructed for the simplified methodology was a Random Forest classifier capable of identifying potential damages at any point in the vicinity of an off-stream reservoir. This ML model was trained using synthetic data, offering an estimation of potential damages by considering the physical characteristics of the structure, the surrounding terrain, and vulnerable areas. During a real case application, the simplified methodology achieved an accuracy rate of 91%. The simplified methodology allows owners and administration to obtain a pre-classification without the need to make a 2D hydraulic model, which saves time and money.Furthermore, an interface called ACROPOLIS was developed, integrating the ML model. Users can apply the simplified methodology through ACROPOLIS, which guides them step by step, providing the overall classification of the off-stream reservoir based on Spanish regulations.Finally, the analysis of uncertainties related to breach formation and the location of the breaking points in reservoirs was integrated. This involved comparing the current deterministic approach for hazard classification and a newly proposed fourth-step probabilistic approach that accounts for uncertainties in constructing hazard maps. The study revealed variations in classifications between scenarios, as different breaking points and breach formations generate diverse classifications that can affect emergency plans. Additionally, the proposed visualization can be used for various purposes, including tracking the evolution of categorization over time due to land use changes.

DOCTORAL DEGREE IN COMPUTER ARCHITECTURE

  • ALI, OMAR SHAABAN IBRAHIM: Optimization techniques for distributed task-based programming models
    Author: ALI, OMAR SHAABAN IBRAHIM
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN COMPUTER ARCHITECTURE
    Department: Department of Computer Architecture (DAC)
    Mode: Normal
    Deposit date: 18/07/2024
    Deposit END date: 31/07/2024
    Thesis director: CARPENTER, PAUL MATTHEW
    Committee:
         PRESIDENT: BULL, JONATHAN MARK
         SECRETARI: JIMENEZ GONZALEZ, DANIEL
         VOCAL: ARAUJO, GUIDO
    Thesis abstract: In HPC, task-based models have gained prominence via the adoption of tasks in OpenMP, as an asynchronous and platform-agnostic high-performance and productive model by annotating existing code, transforming it into a parallel version. A program is expressed as a Directed Acyclic Graph (DAG), whose vertices are units of code called tasks. Edges between tasks represent dependencies between them, and tasks with no logical relationship can be executed concurrently. The task graph is independent of the targeted platform architecture, making these models suitable for concurrent execution on a broad spectrum of platforms such as multi-core SMPs or offloaded to GPUs, FPGAs, or accelerators. Several initiatives explore distributed-tasking approaches, which use the task model to decompose the application across multiple nodes with distributed memory. The advantage is that the application is expressed in a simple and clean manner that reflects only the computations and dependencies. Unfortunately, the distributed tasking approaches suffer from poor efficiency and scalability, which hinder their adoption by the HPC community. This is mainly due to the overhead of task creation and dependency graph construction, which are usually sequential. This thesis proposes two techniques to address this problem. Our first approach relates to task nesting, which mitigates the sequential bottleneck by building the full dependency graph in parallel using multiple concurrently executing parent tasks. A key limitation of task nesting is that a task cannot be created until all its accesses and its descendants’ accesses are known. Current approaches to work around this limitation either halt task creation and execution using an explicit taskwait barrier or substitute dependencies with artificial accesses known as sentinels. We introduce the auto clause, which indicates that the task may create subtasks that access unspecified memory regions, or it may allocate and return memory at addresses that are not yet known. Contrary to taskwait, our approach does not prevent the concurrent creation and execution of tasks, maintaining parallelism and allowing the scheduler to optimize load balance and data locality. In addition, all tasks can be given a precise specification of their own data accesses, unlike sentinels, resulting in a unified mechanism governing task ordering, program data transfers on distributed memory, and optimizing data locality, e.g. on NUMA systems. The auto clause, therefore, provides an incremental path to develop programs with nested tasks by removing the need for every parent task to have a complete specification of the accesses of its descendent tasks while reducing redundant information that can be time-consuming and error-prone to describe. Our second approach takes advantage of the iterative behaviour of many HPC applications, such as those that employ iterative methods or multi-step simulations. Most models construct the full unrolled task graph sequentially despite the fact that these applications create the same directed acyclic graph of tasks on each timestep. We define the programming model based on the taskiter clause, a recently introduced construct in the literature for iterative applications on SMP. We also describe the full runtime implementation to exploit this information to eliminate the sequential bottleneck and control messages while retaining the simplicity and productivity of the existing approach. We integrate both techniques into OmpSs-2@Cluster, the distributed tasking variant of OmpSs-2, and evaluate the performance on the MareNostrum 4 supercomputer.
  • JAMET, ALEXANDRE VALENTIN: Interaction between computer architecture and artificial intelligence
    Author: JAMET, ALEXANDRE VALENTIN
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN COMPUTER ARCHITECTURE
    Department: Department of Computer Architecture (DAC)
    Mode: Normal
    Deposit date: 19/07/2024
    Deposit END date: 02/09/2024
    Thesis director: ÁLVAREZ MARTÍ, LLUC | CASAS GUIX, MARC
    Committee:
         PRESIDENT: ROS BARDISA, ALBERTO
         SECRETARI: CANAL CORRETGER, RAMON
         VOCAL: PERAIS, ARTHUR
    Thesis abstract: Since its inception with the first computing systems, computer architecture has lived through many revolutions and saw plenty of technological innovations. However, a significant challenge has persisted throughout the evolution of computing systems: the Memory Wall. To address this challenge, architects have devised various latency tolerance techniques, including cache hierarchy, cache replacement policies, hardware prefetching, and off-chip prediction. Cache hierarchy involves the use of intermediate memories, such as caches, to store frequently accessed data close to the processor, thereby reducing memory access latencies. Cache replacement policies determine which data blocks should be stored or evicted from caches based on predictions of future reuse. Hardware prefetching mechanisms aim to bring data blocks that are likely to be needed in the near future into the cache proactively. Off-chip prediction predicts whether a load demand request will benefit from cache access or if it will require a DRAM access, allowing for speculative fetching of data blocks from DRAM to hide memory access latencies. This thesis addresses the challenges of cache management and memory access optimization in modern computer architectures, focusing on improving performance and energy efficiency across a variety of workloads. It presents three main contributions. The first contribution critically assesses the effectiveness of contemporary Last Level Cache (LLC) replacement policies across a diverse spectrum of workloads, encompassing graph processing, scientific, industrial applications, as well as standard benchmark suites like SPEC CPU 2006 and SPEC CPU 2017. Despite exhibiting notable performance enhancements in conventional benchmark scenarios, these existing LLC replacement policies often falter in capturing the nuanced access patterns characteristic of modern High-Performance Computing (HPC) and big data workloads. In response to this challenge, two novel LLC replacement policies, namely Multi-Sampler Multiperspective (MS-MPPPB) and Multiperspective with Dynamic Features Selector (DS-MPPPB), are introduced and rigorously evaluated. Demonstrating superior efficacy across a broad array of workloads, these innovative policies offer heightened performance benefits tailored specifically for HPC and big data applications. The second contribution is dedicated to enhancing memory access patterns, specifically for graph-processing workloads. These workloads are renowned for their irregular memory access patterns and suboptimal data locality. This contribution targets the first level of the cache hierarchy, as careful analysis reveals that, when considering graph-processing workloads, the vast majority of L1D misses eventually require a DRAM access. Introducing the innovative Large Predictor (LP), this endeavor aims to discern between regular and irregular memory accesses, channeling irregular accesses efficiently through a dedicated Side Data Cache (SDC). By synergizing LP with SDC, notable performance enhancements are achieved, surpassing conventional cache hierarchies and state-of-the-art cache replacement policies, particularly within the realm of graph-processing applications. The third contribution presents the Two Level Perceptron (TLP) predictor, a sophisticated approach that integrates off-chip prediction with adaptive prefetch filtering within the first-level data cache (L1D). Leveraging a dual-layered structure composed of the First Level Predictor (FLP) and Second Level Predictor (SLP), TLP effectively mitigates average DRAM transactions while enhancing overall performance across both single-core and multi-core workloads. Collectively, these contributions advance the state-of-the-art in cache management and memory access optimization, providing insights and techniques to enhance the performance and energy efficiency of modern computer architectures across a variety of workloads.
  • NAVARRO MUÑOZ, ANTONI: Enhancing HPC efficiency: adaptive resource management and scheduling through online monitoring and prediction systems
    Author: NAVARRO MUÑOZ, 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 COMPUTER ARCHITECTURE
    Department: Department of Computer Architecture (DAC)
    Mode: Normal
    Deposit date: 22/07/2024
    Deposit END date: 04/09/2024
    Thesis director: BELTRAN QUEROL, VICENÇ | AYGUADÉ PARRA, EDUARD
    Committee:
         PRESIDENT: PERICAS GLEIM, MIQUEL
         SECRETARI: MARTORELL BOFILL, XAVIER
         VOCAL: DURAN GONZÁLEZ, ALEJANDRO
    Thesis abstract: High-Performance Computing (HPC) systems continuously evolve, driven by user needs and technology trends. Over the decades, research involving HPC systems has gone from exclusively prioritizing time-to-solution and performance to including energy efficiency and system throughput as equally important objectives. Although the approaches to tackle these objectives may vary, energy efficiency and system throughput are symbiotic, as often improving the latter enhances the former. Several software components seamlessly relate to these objectives, from applications, programming models, and runtime systems to job schedulers and operating systems.Nonetheless, parallel programming models aid HPC users in achieving these objectives by abstracting the intricacies of the underlying system. Hence, runtime systems are crucial in coping with the surfaced challenges. Runtime systems can gather precise and fine-grained profiling information and leverage it to implement advanced scheduling and resource management heuristics to optimize the execution of applications.However, current implementations are either too naive and static to cope with the irregularity and dynamism of today’s applications or introduce adverse effects in the form of overhead and complexity. To overcome these drawbacks, current runtime systems should utilize techniques that optimize system throughput adaptively through informed decisions rather than statically tailoring settings per execution.This thesis’s main objective is to design and develop a precise and low-overhead online monitoring and prediction infrastructure that provides all the necessary capabilities to enhance resource management and scheduling techniques for HPC systems. Our research finds that, based on the information provided by our monitoring infrastructures, creating adaptive techniques or enhancing existing ones can improve performance and energy efficiency compared to the static methods found in the literature. Furthermore, through a novel design, our monitoring infrastructures provide accurate and fine-grained metrics and predictions with negligible overhead while in an online operating mode.Finally, our contributions demonstrate how system throughput and energy efficiency can improve by leveraging detailed information from the runtime systems and system job schedulers.
  • SALA PENADÈS, KEVIN: Exploiting synergies between message-passing and task-based programming models
    Author: SALA PENADÈS, KEVIN
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN COMPUTER ARCHITECTURE
    Department: Department of Computer Architecture (DAC)
    Mode: Normal
    Deposit date: 15/07/2024
    Deposit END date: 26/07/2024
    Thesis director: BELTRAN QUEROL, VICENÇ | AYGUADÉ PARRA, EDUARD
    Committee:
         PRESIDENT NO PRESENCIAL: BULL, JONATHAN MARK
         SECRETARI: MARTORELL BOFILL, XAVIER
         VOCAL: THIBAULT, SAMUEL
    Thesis abstract: Modern supercomputing systems feature thousands of computing nodes that already provide hundreds of cores. Parallelizing scientific and engineering applications to leverage all these resources has become a significant challenge for the HPC community. Any application that aims to perform well at scale must efficiently orchestrate and exploit both inter- and intra-node parallelism. Multiple programming models exist to exploit each of these parallelism classes. MPI and OpenMP are de facto standards for distributed- and shared-memory parallelism, respectively. MPI is a message-passing interface based on processes with separate virtual address spaces, while OpenMP defines thread-based and task-based interfaces for shared-memory parallelization. Applications can combine both types of programming models to take advantage of their particular benefits in a technique called hybrid parallel programming.Combining task-based and message-passing programming models is a promising hybrid approach that can provide a high-performance data-flow model without damaging the programmability of applications. An application can be represented as a set of directed acyclic graphs (DAGs) with one independent graph per process. Vertices represent tasks comprising computations and communications, edges represent the data dependencies among tasks, and the tasks from distinct processes (i.e., different DAGs) can communicate through message passing. This way, the intra- and inter-node parallelism is smoothly orchestrated through the task graphs. Moreover, this data-flow approach has other benefits: fine synchronizations through data dependencies and inter-process messages, the natural overlap and intertwining of application phases (e.g., computation and communication), and an automatic load balancing within each process. However, the current standards (e.g., MPI and OpenMP) prevent tasks from issuing communications efficiently, as severe performance and programmability issues must be tackled.This thesis designs and implements software solutions that allow task-based applications to efficiently incorporate communications inside their task graphs. We solve the well-known interoperability issues between task-based and message-passing programming models through two task-aware libraries. The two new libraries provide full support to application tasks that issue communications through task-aware communication operations, which can feature blocking or non-blocking semantics. The TAMPI library supports two-sided MPI communications (e.g., send/receive and collectives), and the TAGASPI library supports the one-sided communications (also known as RMA) provided by the GASPI interface. Furthermore, our task-aware mechanisms are generic enough to incorporate any other blocking or non-blocking interface (e.g., for GPU offloading) with task-based models.Our hybrid data-flow approach, which combines tasking and message passing, provides performance, scalability, and programmability for task-based applications on highly parallel systems. We demonstrate these benefits by porting several benchmarks and applications and comparing our approach with other state-of-the-art techniques.

DOCTORAL DEGREE IN COMPUTING

  • ALEMANY PUIG, LLUIS: Theory, Algorithms and Applications of Linear Arrangements of Trees: Generation, Expectation and Optimization
    Author: ALEMANY PUIG, LLUIS
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN COMPUTING
    Department: Department of Computer Science (CS)
    Mode: Normal
    Deposit date: 15/07/2024
    Deposit END date: 26/07/2024
    Thesis director: FERRER CANCHO, RAMON
    Thesis abstract: A successful approach to represent the syntactic structure of sentences in Computational Linguistics, founded in the theory developed by Tesnière, is that of syntactic dependency tree. Pairs of vertices of syntactically-related words are joined with an edge that carries a label which indicates the type of syntactic relationship. When words and syntactic relationships are abstracted away, by removing the vertex labels and removing the edge labels with the type of syntactic relationship, we are left with a so-called linearized tree. A linearized tree is simply a rooted tree in conjunction with a linear arrangement. And a linear arrangement of a graph is a permutation of the graph's vertices, and can be represented by drawing the vertices on a horizontal line and the edges as semicircles above it.There exist many computational problems that involve linear arrangements of graphs. Remarkable examples are those that look for an arrangement that optimize the sum of edge lengths, where the length of an edge is defined as the absolute value of the difference of the positions of the endpoints of the edge in the arrangement. The problem that minimizes this sum is known as the minimum Linear Arrangement problem (minLA). When one maximizes the sum of edge lengths, the problem is known as the Maximum Linear Arrangement problem (MaxLA). In an attempt to provide a theory of word order, language researchers put forward the now well-known Dependency Distance minimization principle after observing and providing large-scale evidence of the tendency in languages to minimize the total sum of edge lengths in the syntactic dependency trees of their sentences. In order to provide an exhaustive theory of word order, some language researchers have also argued that MaxLA manifests itself in languages in substructures of the syntactic dependency trees isomorphic to a star graph.Both minLA and MaxLA are known to be NP-Hard on general graphs, and only minLA is known to be solvable in polynomial time on trees and other classes of graphs. In this thesis we contribute with optimal algorithms to solve several constrained variants of both minLA and MaxLA. We study these two problems for bipartite graphs under the constraint that vertices have to be arranged in two disjoint intervals according to the vertex partition they belong (bipartite arrangements). These are also studied for free trees under the constraint that edges are not allowed to cross in the arrangement (planar arrangements), and for rooted trees under the constraint that the arrangement is planar and the root is not covered (projective arrangements). We also tackle the unconstrained formulation of MaxLA for free trees. Our efforts have yielded polynomial-time solutions for k-linear trees (0 <= k <= 2) and a 3/2-approximation algorithm. Furthermore, we devise algorithms and derive formulas to calculate the expected value of the cost of bipartite arrangements of bipartite graphs, and planar and projective arrangements of trees, based on new knowledge on how to generate such arrangements uniformly at random. All these algorithms, and others as well, have been packaged into the Linear Arrangement Library (LAL), licensed under the GNU Affero GPL.

DOCTORAL DEGREE IN ELECTRICAL ENGINEERING

  • DEL POZO GONZÁLEZ, HÉCTOR: Control of Floating Offshore Energy Hubs
    Author: DEL POZO GONZÁLEZ, HÉCTOR
    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 ELECTRICAL ENGINEERING
    Department: Department of Electrical Engineering (DEE)
    Mode: Normal
    Deposit date: 25/07/2024
    Deposit END date: 06/09/2024
    Thesis director: GOMIS BELLMUNT, ORIOL | DOMÍNGUEZ GARCÍA, JOSÉ LUIS
    Committee:
         PRESIDENT: ANAYA LARA, OLIMPO
         SECRETARI: PRIETO ARAUJO, EDUARDO
         VOCAL: GEBRAAD, PIETER MARINUS OTTO
    Thesis abstract: The significant worldwide offshore potential has garnered considerable interest from energy companies and oil and gas plant owners in recent years. With significant advancements in bottom-fixed structures, floating technologies have emerged to unlock potential in deeper waters, where wind resource is abundant. Although most existing systems today are pilot projects or parks with up to 11 turbines, such as the case of Hywind Tampen, it is estimated that in the coming years, the large-scale deployment of floating wind farms will become a reality. This evolution towards extensive integration of offshore wind energy not only poses a significant challenge for the wind sector but also for transmission and energy storage sectors, where hydrogen has emerged as a key technology to provide flexibility to excess generated energy and to compete not only in the electricity market but also in hydrogen/gas markets; such technology could provide stationary storage.However, there is limited research on how these offshore energy hubs could be developed or how their optimal operation would be. Many questions remain unanswered, such as how to optimize floating wind farms to reduce their costs? Is their combination with other energy sources such as wave energy optimal? What is the optimal allocation of floating wind energy to hydrogen for its operation?This thesis aims to address the paradigm of offshore energy hubs dominated by floating wind and their potential optimization and control, both individually and in combination with other existing energy sources such as wave or hydrogen, to reduce the total cost of installations and in many cases to utilize the same infrastructure. To achieve this, hybrid floating wind-wave technologies that can be installed near the coast and reversible hydrogen systems through solid oxide cell technology are primarily employed, allowing for both hydrogen production and bidirectional energy injection into the grid from hydrogen.Although this thesis presents conservative case studies for potential implementation feasible by Transmission System Operators (TSOs), it does not imply that these configurations are optimal or that they would necessarily be the options implemented by TSOs in hypothetical case studies. This thesis primarily presents case studies with data from locations in northern Spain, but it also explores the paradigm of energy islands in Denmark. These are the two potential implementation sites studied in this thesis. The main conclusions of this thesis are summarized in that the dynamics of floating offshore energy require advanced control techniques that allow for long-term optimization of their operation to avoid power losses while extending their lifespan.

DOCTORAL DEGREE IN ENVIRONMENTAL ENGINEERING

  • ETXANDI SANTOLAYA, MAITE: A new approach for End of Life Estimations in Electric Vehicle Batteries: Maximizing Battery Usage
    Author: ETXANDI SANTOLAYA, MAITE
    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: Department of Civil and Environmental Engineering (DECA)
    Mode: Normal
    Deposit date: 16/07/2024
    Deposit END date: 29/07/2024
    Thesis director: CORCHERO GARCIA, CRISTINA | CANALS CASALS, LLUC
    Committee:
         PRESIDENT: BENVENISTE PÉREZ, GABRIELA
         SECRETARI: DÍAZ GONZÁLEZ, FRANCISCO
         VOCAL: REDONDO IGLESIAS, EDUARDO
    Thesis abstract: The adoption of Electric Vehicles (EVs) requires careful management of their resource-intensive batteries to make sure that the transition does not come at a high environmental cost. Technological advancements and cost reductions have led to increased battery capacities and substantial expected residual value in retired batteries, highlighting the importance of circular economy practices, such as sharing and repurposing.Effective decision-making in the battery lifecycle requires precise estimation of End of Life (EoL). Current methods use a universal criterion of 70-80% State of Health (SoH) for defining the EoL, but this overlooks the individualities of each driver and their EV battery capacity.The initial part of the thesis assesses the adequacy of the universal EoL criteria. It begins by analysing the driving performance of EVs to identify new criteria for determining the functional EoL based on specific driving needs. Subsequently, the functional EoL thresholds for various realistic use cases are obtained using driving profiles derived from a proposed synthetic driving cycle model. The findings indicate that underperformance is influenced by factors such as battery capacity, charging frequency, and driving times, highlighting the shortcomings of current EoL estimates.Recognizing the limitations of the fixed EoL criteria, the second part of the thesis introduces a novel approach for EoL estimation using the State of Function (SoF). This approach considers historical driving requirements to define individualize EoL thresholds and employs a data-driven algorithm to predict the SoH under real-world operating conditions (i.e. partial charges). Both aspects, EoL requirements and battery degradation, are included in the proposed definition of the SoF, measuring how far the battery is from underperforming.The thesis results advocate shifting from the 70-80% SoH EoL criterion to the SoF measure to improve EoL estimations. In addition, understanding the functional EoL allows exploration of alternatives like Vehicle to Grid (V2G) and second-life applications to maximize battery usage, reduce residual value when reaching the recycling stage, and minimize environmental impact.
  • GONZALEZ ROMERO, ADOLFO: Understanding sediment formation processes, properties and dust emission potential in desert dust hotspot regions
    Author: GONZALEZ ROMERO, ADOLFO
    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: Department of Civil and Environmental Engineering (DECA)
    Mode: Article-based thesis
    Deposit date: 16/07/2024
    Deposit END date: 29/07/2024
    Thesis director: QUEROL CARCELLER, XAVIER | PEREZ GARCIA-PANDO, CARLOS
    Committee:
         PRESIDENT: DE LA ROSA DÍAZ, JESÚS DAMIAN
         SECRETARI: CASTILLO FERNÁNDEZ, SONIA
         VOCAL: DI BIAGIO, CLAUDIA
    Thesis abstract: Desert dust, primarily composed of mineral particles from arid and semiarid regions, irnpacts the Earth's atmosphere, climate, ecosystems and human health. To better eva!uate these impacts, desert dust models must reduce uncertaintles, which partly stem from inadequate characterization of sediment properties. In this study, samples were co!lected from four regions (Morocco, lceland, Mojave Desert and Jordan), including crusts (ephemeral lake top sediments), paved sediments (eroded crusts by aeolian processes), sediments and aeolian ripples (transported by wind). These were analysed far particle size, aggregatlon state, mlnera!ogy and Fe modes of occurrence. The results yielded four conceptual models far the formation of dust-emitting sediments, highlighting their physicochemical properties. These models can guide future studies in obtaining relevant information from other dese1t dust hotspots for improved dust model!ing. Prior to sampling, it is crucial to characterize the region using various approaches, including geological background, sedimentology, and remete sensing, to accurately identify dust-emitting sources. Lowlands, being the rnost emissive areas, should be prioritized, with samples taken frorn the top few centimetres of soil. The particle aggregation state can be assessed by comparing the fu!ly and minimally dispersed particle size distributions, which is critica! for desert dust emission models. Crusts, the most common sedirnents in lowlands, are typically enriched in finer minerals, precipitated minerals, and total Fe content. This detailed characterization ensures that sampling accurately represents the dust-emitting areas. The first conceptual model !acuses on mid-latitude dust hotspots (MLDH), where ephemeral lakes and floodplains serve as the primary dust sources. These areas exhibit significant dust-emitting fluxes primarily driven by aeo!ian ripples and sa!tation, breaking the crusts in lowlands, which are characterized by a high particle aggregation state, finer particle size, and elevated clay and exchangeable Fe contents comparad to highlands. A variation of this rnodel, also for MLDHs, lncludes lowland crusts with high precipitation of carbonate and salt minerals, as seen in the White Desert of Jordan. The state of aggregation in these areas depends on whether precipitation processes accumulate as cement oras single minera! particles, with total Fe content diluted by mineral precipitation. Another variant pertains to aeolian sediments deposited in lowlands from desert dust storms, such as in the Black Desert. Here, crusts form from aeolian deposition and scarce rain accumulation in small depressions within the basalt field. Mineralogical evidence indicates that these sediments originate from aeolian transport from neighbouring dust hotspots rather than local weathering substrata (basalt fields), resulting in a low to mid particle aggregation state. Dust emission in these regions is limlted due to the rugged terrain of the basalt fields and the absence of aeolian ripples. The final conceptual model pertains to a high-latitude dust hotspot (HLDH), exemplified by lceland. This model is characterized by a unique combination of volcanic geology and a glacial environment. Glacial meltwaters release large volumes of paleo-volcanic ash, stored in the glacier's ice for millennia, into the river systems. A recent volcanic eruption formed a basaltic field, acting as a natural dam and creating an epherneral lake where fine ash and sediments are deposited. The mineralogy is predorninantly volcanic glass, with a significantly higher total Fe contentlfl<ee times that of MLDHsaed high abundance of magnetite. The absence of carbonates, salts, and clays contributes to the low aggregation state of these particles. These sediments, with their fine partic!e size and low particle aggregation state, are highly prone to dust emissions by saltation and potentia!ly aerodynamic entraínment.

DOCTORAL DEGREE IN GEOTECHNICAL ENGINEERING

  • BARANDIARÁN VILLEGAS, LUCÍA BELÉN: THM numerical modeling of multiphase flow in fractured rock masses using zero-thickness interface elements
    Author: BARANDIARÁN VILLEGAS, LUCÍA BELÉN
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN GEOTECHNICAL ENGINEERING
    Department: Department of Civil and Environmental Engineering (DECA)
    Mode: Normal
    Deposit date: 18/07/2024
    Deposit END date: 31/07/2024
    Thesis director: CAROL VILARASAU, IGNACIO | LOPEZ GARELLO, CARLOS MARIA
    Committee:
         PRESIDENT: PRAT CATALAN, PERE
         SECRETARI: SEGURA SERRA, JOSE MARIA
         VOCAL: XOTTA, GIOVANNA
    Thesis abstract: To address the impacts of climate change, several measures have been suggested among which utilizing renewable energy sources such as geothermal energy and implementing technologies such as hydrogen storage or CCUS. Some of these solutions imply the injection of fluids into fractured rock masses (e.g. depleted O&G reservoirs) with the subsequent change in local stress conditions. This alteration may lead to the initiation of micro-seismic events by reactivating existing faults or the generation of new fractures, with the risk of ultimately establishing pathways for fluid leakage. Additionally, depleted reservoirs contain multiphase and multicomponent fluids that could react chemically with the new injection fluids. Therefore, the accurate prediction of operation conditions demands advanced geomechanical software capable of evaluating the viability and safety of potential extraction or storage locations. In this context, the main objective of this thesis is to develop a thermo-hydro-mechanical multiphase model in fractured porous medium with the Finite Element Method using zero-thickness interface elements to model discrete discontinuities. The main assumptions of the model are: the small strain theory, the system composition with two fluid phases (liquid and gas), two species (water and dry gas) and one solid phase. The gas phase follows the ideal gas law and the liquid phase evaporation is considered. The main variables are: displacements, phase pressures and temperature. The formulation takes into account: the equilibrium equation, the mass balance equation of the water species, the mass balance equation of the gas species and the balance of energy. The formulation of the discontinuities considers similar assumptions as the porous medium and takes into account a reduction factor of the water retention curve parameters based on the mechanical opening of the fracture. The model has been implemented and validated with academic verification examples in a FE code.However, some limitations were observed related to the time integration scheme, the treatment of storage terms of the governing equations and the mass flow. This issues have motivated the following new developments: new mass-conservative approach for diffusion equations using FE formulations, a new physically-based exponential model which considers the pore size or aperture distribution in case of the porous medium or discontinuities, respectively, and a new damage-frictional law which properly models discontinuity closure.
  • CUI, HONGZHI: Susceptibility assessment of shallow landslides at the regional scale using physically-based models and probabilistic approaches
    Author: CUI, HONGZHI
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN GEOTECHNICAL ENGINEERING
    Department: Department of Civil and Environmental Engineering (DECA)
    Mode: Change of supervisor + Article-based thesis
    Deposit date: 15/07/2024
    Deposit END date: 26/07/2024
    Thesis director: HURLIMANN ZIEGLER, MARCEL | JI, JIAN
    Committee:
         PRESIDENT: ZHU, HONGHU
         SECRETARI: MOYA SANCHEZ, JOSE
         VOCAL: ZHANG, WENGANG
         VOCAL: ZHONG, QIMING
         VOCAL NO PRESENCIAL: ABANCÓ MARTÍNEZ DE ARENZANA, CLÀUDIA
    Thesis abstract: This thesis focuses on the evaluation of shallow landslide susceptibility in mountainous areas induced by rainfall or seismic events. The primary aim is to efficiently assess regional-scale landslide susceptibility based on physical modelling within a probabilistic framework while accounting for uncertainties arising from complex geological conditions and challenges related to data collection. The study proposes an innovative framework for probabilistic landslide susceptibility assessment by introducing the first-order reliability method (FORM) in the platform of geographic information system (GIS), called “"GIS-FORM”". This method effectively addresses the challenge of considering uncertainty in geotechnical parameters methods at the regional scale. In response to the challenge of inefficient computation and low prediction accuracy in regional-scale shallow landslide susceptibility assessment caused by transient rainfall-induced, a simplified instantaneous rainfall infiltration model was proposed based on integrating the GIS-FORM method. The model simulates the variation of the wetting front depth due to the vertical infiltration of rainfall and surface run-off. Subsequently, a general software program was developed for Windows platforms. The results show that the coefficient of variation (COV) of random parameters, statistical correlation, and non-normal distribution have a significant impact on the landslide probability assessment. A rapid assessment framework for the probabilistic susceptibility evaluation of shallow landslides at the regional scale is proposed by integrating the “code "Fast Shallow Landslide Assessment Model" (FSLAM) and GIS-FORM. The study reveals that hydrological conditions can significantly influence the spatial distribution of landslides, particularly under the combined impacts of antecedent rainfall and event rainfall. The extent of the high susceptibility area is observed to increase considerably when the event rainfall is between 77 and 107 mm. To further improve the accuracy of susceptibility assessments, this study proposes an innovative clustering method by utilising image processing techniques. This approach effectively simplifies the raster outcome and markedly enhances the prediction accuracy of susceptibility assessment as well.

DOCTORAL DEGREE IN NETWORK ENGINEERING

  • TOBAR NICOLAU, ADRIÁN: Syntactic privacy in continuous data publishing
    Author: TOBAR NICOLAU, ADRIÁN
    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: 18/07/2024
    Deposit END date: 31/07/2024
    Thesis director: FORNE MUÑOZ, JORGE | PARRA ARNAU, JAVIER
    Committee:
         PRESIDENT: DOMINGO I FERRER, JOSEP
         SECRETARI: AGUILAR IGARTUA, MONICA
         VOCAL: JUÁREZ, MARC
    Thesis abstract: The issue of data sharing and the protection of individual privacy is a significant challenge in modern society. The concept of privacy preserving data publishing addresses this problem by enabling the sharing of valuable sensitive data while protecting the legal right to privacy of the individuals who share it. Allowing access to this information is of great value for the proper development of research and various technologies without the burden of strict privacy regulations that private information implies. In this thesis, we have focused on the study of a particular data publishing framework: continuous data publishing, where data is published continuously while being updated between publications.The principal contributions of this thesis to the area of continuous data publishing are described next.Firstly, we have structured the existing corpus of literature. We have identified the principal categories of attackers and organised the existing proposals based on their attacker capacities, privacy guarantees and dataset type.Secondly, we examined the requirements for m-invariance, a state-of-the-art proposal, and how to achieve these requirements in an efficient manner. Existing techniques for generating private datasets necessitate the enforcement of the m-eligible condition, which restricts the distribution of sensitive data values within the dataset. We have investigated the significance of this property and the most efficient methods for handling datasets that do not fulfil m-eligibility, thereby minimizing the loss of utility.Thirdly, we have developed a computationally intensive approach to optimize the utility of publications. Existing algorithms based on the m-invariance notion are simple heuristics that do not prioritize the maximization of data quality but rather the velocity of execution. We have created an alternative approach that is devoted to optimizing data quality. The results demonstrate a substantial enhancement in utility relative to previous algorithms.Finally, we have proposed two novel privacy notions for continuous data publishing. The first is a,m-warden, a privacy notion that limits the capacity of a probabilistic attacker. This is an malicious observer that, knowing the user's data, can infer with a certain probability the sensitive information of the target. On the other hand, m-USP is a privacy notion designed to permit the republication of data between two non-communicating data publishers, while simultaneously preventing attacks derived from the non-coordinated publication of data.

DOCTORAL DEGREE IN NUCLEAR AND IONISING RADIATION ENGINEERING

  • VERGARA FERNANDEZ, ESTRELLA: COORDINATION MANAGEMENT AND DEPENDABILITY ENGINEERING METHODS FOR A LARGE-SCALE FACILITY
    Author: VERGARA FERNANDEZ, ESTRELLA
    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 NUCLEAR AND IONISING RADIATION ENGINEERING
    Department: Department of Physics (FIS)
    Mode: Normal
    Deposit date: 18/07/2024
    Deposit END date: 31/07/2024
    Thesis director: CALVIÑO TAVARES, FRANCISCO
    Committee:
         PRESIDENT: BARBERO SOTO, ESTHER
         SECRETARI: CORTES ROSSELL, GUILLEM PERE
         VOCAL: FERNANDEZ HERNANDO, LLUIS
    Thesis abstract: The CERN accelerator complex is a sophisticated network of accelerators and detectors used for high-energy physics research. The Large Hadron Collider (LHC), the last accelerator in this sequence, is designed for head-on proton collisions at a center-of-mass energy of 14 TeV. Managing such a complex and large-scale scientific facility requires meticulous coordination and dependability engineering to execute interventions, upgrades, and maintenance effectively throughout its scheduled shutdown periods, the so-called Programmed Stops.This thesis demonstrates that coordination management of the Programmed Stops of a particle accelerator such as the LHC can be viewed as managing a complex engineering system. It integrates dependability studies with project management techniques, presenting a robust framework for planning, executing, and managing interventions and upgrades. This approach ensures the LHC's reliability, efficiency, and safety, benefiting current and future scientific endeavours.This thesis offers a comprehensive framework combining system engineering principles with dependability analysis. This ensures systematic addressing of all coordination management aspects, improving planning, and execution reliability, and efficiency. The research underlines the importance of detailed resource analysis and levelling to ensure planning feasibility and successful completion within given constraints. This approach aims to optimize resources and improve the coordination management. Various tools and techniques have been developed and implemented to oversee the LHC coordination management, that has been applied also to other CERN facilities. This thesis successfully establishes that effective coordination management of the LHC, treated as a complex engineering system, significantly enhances its operational reliability and efficiency. By integrating dependability studies with project management techniques, it provides a robust framework for planning, executing, and managing the coordination of interventions and upgrades. This thesis emphasizes that the methodologies and tools presented are applicable to other large-scale scientific projects, providing a valuable reference for managing such projects and installations.

DOCTORAL DEGREE IN PHOTONICS

  • CUNQUERO NAVARRO, MARINA: Use of Advanced Imaging Tools for Assessing the Performance of Novel Therapeutic Techniques for Restoring Vision
    Author: CUNQUERO NAVARRO, MARINA
    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: 18/07/2024
    Deposit END date: 31/07/2024
    Thesis director: LOZA ALVAREZ, PABLO | MARSAL TERÉS, MARIA
    Committee:
         PRESIDENT: PICAUD, SERGE
         SECRETARI: KRIEG, MICHAEL
         VOCAL: ACCANTO, NICOLO
    Thesis abstract: Studying vision restoration is paramount for addressing degenerative blinding diseases, which significantly impact quality of life and public health. With more than 230M people worldwide affected by moderate to severe vision loss, and an estimated increase in blindness from 38M to 115M by 2050, the urgency for effective treatments is clear. Vision, being the most complex and crucial human sense, relies on an intricate network of structures. Light is captured by photoreceptors in the retina and translated into neural signals processed by the brain, enabling sight. Degenerative diseases often involve the progressive deterioration of photoreceptors, leading to blindness. Currently, there is no cure but various approaches are being researched to restore sight. These include gene and cell therapies targeting diseased tissue, as well as methods like optogenetics and neuroprosthetics to modulate neuron activity and bypass dysfunction. By understanding and manipulating neural activity, scientists aim to restore vision or slow down the degenerative processes.The results of this PhD thesis highlight progress across four areas for vision restoration research. Chapter 2a explores a new retinal implant using biocompatible reduced graphene oxide microelectrodes, demonstrating its ability to record neural signals from retinal tissue and capture light-induced firing patterns in retinal ganglion cells. It also details a protocol for retinal calcium imaging, facilitating future studies combining electrical stimulation with optical techniques. Chapter 2b focuses on adapting an ophthalmoscope for in vivo, single-cell resolution imaging of the retina in rodents, aiming to set the basis for future implementations to monitor the functionality of implanted retinal prostheses. Chapter 3 delves into the potential of human-induced pluripotent stem cell-derived retinal organoids for vision research. Using advanced imaging techniques, researchers successfully observed the formation of distinct retinal cell types within the organoids and identified differences in calcium dynamics between healthy and diseased models. Future work aims to refine MEA recordings and investigate the link between retinal organoid structure and function. Chapter 4 introduces a novel three-photon excitation technique offering deeper brain penetration and higher precision compared to traditional methods. This approach successfully regulates neuronal activity in zebrafish with minimal light exposure, showcasing its potential for revolutionizing the study of neural circuits and development of neuromodulation therapies.Taken together, these advancements across retinal implant design, in vivo monitoring of the retina, studying the potential of patient-derived organoid models, and development of non-invasive three-photon brain stimulation techniques, pave the way for future development of more effective vision restoration therapies.

DOCTORAL DEGREE IN POLYMERS AND BIOPOLYMERS

  • BALLESTAR DE LAS HERAS, RICARDO LUIS: Manufacturing and recycling of polyolefins and biopolymers in a circular economy model. Mechanical, thermal and morphological characterization of polymers and high-performance films.
    Author: BALLESTAR DE LAS HERAS, RICARDO LUIS
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN POLYMERS AND BIOPOLYMERS
    Department: Department of Chemical Engineering (EQ)
    Mode: Article-based thesis
    Deposit date: 26/07/2024
    Deposit END date: 09/09/2024
    Thesis director: COLOM FAJULA, XAVIER | CAÑAVATE AVILA, FRANCISCO JAVIER
    Thesis abstract: On April 29th, 2015, the EU enacted Directive 2015/720, aimed at reducing plastic consumption, promoting the use of reusable bags and encouraging the replacement of single-use plastic bags with biodegradable alternatives. This European legislation was transposed into Spanish law by Royal Decree 293/2018, dated May 18th.This legislation and its accompanying regulations have significantly impacted the transformation sector, forcing it to reinvent itself to continue its activities. This work aims to provide answers to the challenges faced by manufacturers due to this new context, as well as address the needs resulting from it. Distinctive features of this project are its practical nature and industrial scale.A primary objective is to establish the processability and quality windows for recycled post-industrial and post-consumer materials, ensuring the production of a final product with predefined quality standards. The study examines three types of polyethylene: virgin, post-industrial, and post-consumer. Each type undergoes a combined cycle simulating an industrial recycling process, with post-industrial material being processed up to twelve times and post-consumer material up to four times. This methodology of cyclic processing supports the principle of circularity in sample characterization.For each cycle, involving extrusion and recycling, the study examines micro and macroscopic changes, analyzing morphological and structural changes (using DSC, TGA, GPC, and FTIR techniques) and the evolution of mechanical properties (tensile strength, elongation at break, tear resistance, impact resistance (dart test), and colorimetric changes).At the microstructural level, two types of crystalline structures are observed, and they evolve differently through the processing cycles due to the thermo-oxidative degradation phenomena that occur along the process. The changes include a reduction in crystallinity due to the breakdown of more linear and less branched chains, and an increase in cross-linking among more branched structures. These microstructural changes affect post-industrial and post-consumer recycled polyethylene differently.Macroscopically, tear resistance is the most critical property affected during the recycling cycles, decreasing by up to 40% from the initial value and potentially becoming the main limitation for the successive reuse of these polymers.In line with the previously mentioned regulations, biodegradable polymers are another focus of interest. The study examines biodegradable compostable polymers used to manufacture single-use bags. A secondary objective is to determine how long these biodegradable polymers retain their usability properties under standard storage conditions, analyzing the samples over twelve consecutive months.Macroscopically, a progressive loss in tensile, elongation, and impact properties is the most significant phenomenon. Microscopically, two degradation mechanisms—hydrolysis and thermo-oxidation—are observed, both occurring in the amorphous phase of the material.The study concludes that the tested bags have a shelf life of over twelve months under standard storage conditions.
  • FONTANA ESCARTIN, ADRIÁN: Autonomous Diagnostic Systems: Design of Sensors Capable of Recognizing and Releasing Biomolecules
    Author: FONTANA ESCARTIN, ADRIÁN
    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 POLYMERS AND BIOPOLYMERS
    Department: Department of Chemical Engineering (EQ)
    Mode: Normal
    Deposit date: 26/07/2024
    Deposit END date: 09/09/2024
    Thesis director: ALEMAN LLANSO, CARLOS ENRIQUE | BERTRAN CÀNOVAS, ÒSCAR
    Thesis abstract: This Ph.D. thesis delves into the realm of electrochemical biosensors, pivotal devices enabling the sensitive and timely detection of diverse biomolecules. Specifically, it explores the critical role of biosensors in biomedical applications, where the swift identification of biomarkers like Glucose (G), Dopamine (DA), Serotonin (SE), and Nicotinamide Adenine Dinucleotide (NADH) is imperative for diagnosing conditions such as diabetes, Parkinson's disease, Alzheimer's disease, and emerging infections, among other diseases.The thesis offers an in-depth examination of various biosensors engineered to target specific biomolecules, elucidating the methodologies and recent advancements pivotal in shaping device development. Noteworthy is the investigation into the influence of different materials, including conducting polymers (CPs), ceramic materials, carbon-based materials among others, on biosensor performance. Special attention is devoted to the design of intricate nanocomposites aimed at achieving heightened selectivity and sensitivity.Incorporating conducting polymers (CPs) like PEDOT into biosensors has proven successful, especially in detecting Nicotinamide Adenine Dinucleotide (NADH) from various bacteria. This enhances sensor conductivity and sensitivity, crucial for identifying bacterial activity. Notably, this thesis implements this approach in biomedical devices such as sutures and meshes, expanding biosensor applications to infection detection.On another front, the thesis highlights the success of engineering biosensors from 3D printed insulating thermoplastics for the detection of Dopamine (DA) among other biomolecules. Leveraging innovative strategies, these biosensors demonstrate remarkable selectivity and sensitivity in detecting DA, paving the way for enhanced diagnosis and monitoring of neurological disorders and other related conditions.Furthermore, the thesis explores the engineering of conductive devices based on biological materials such as Alginate hydrogels and peptides. These bio-inspired materials offer unique properties conducive to biosensor development, including biocompatibility and tunable conductivity. By harnessing the inherent characteristics of biological materials, novel biosensors with enhanced performance and functionality can be realized, opening new avenues for biomedical diagnostics and therapeutic interventions.Through this comprehensive exploration of diverse biosensor technologies and strategies, the thesis aims to contribute significantly to the ongoing evolution of electrochemical biosensors. By shedding light on the successful incorporation of advanced materials and innovative engineering approaches, it offers valuable insights into the potential of biosensors for transformative applications in various biomedical fields, ultimately advancing the frontiers of medical diagnosis and treatment.
  • QIZILBASH, MASOOMA: Computational Fluid Dynamic (CFD) Study of Polymer Microencapsulation Processes
    Author: QIZILBASH, MASOOMA
    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 POLYMERS AND BIOPOLYMERS
    Department: Department of Chemical Engineering (EQ)
    Mode: Normal
    Deposit date: 26/07/2024
    Deposit END date: 09/09/2024
    Thesis director: GUARDO ZABALETA, ALFREDO DE JESUS | DEL VALLE MENDOZA, LUIS JAVIER
    Thesis abstract: Microencapsulation process of polymers and biopolymer is the most important technique in a polymer industry to make it unique and applicable in various fields of daily life. When it comes to the accuracy of the method only Computational Fluid Dynamic (CFD) simulations or numerical solution provides the authenticity of the method. CFD analysis gives a more schematic approach instead of any other Simulation method.In this thesis detailed use of governing equations of CFD is used to predict the accuracy of the microencapsulation method. The experimentation was done in the laboratory of the department of polymers and biopolymers under the supervision of Prof Luis J. Dell Valle. By using CFD the results are more precise, clear and accurate along with the zero minimum percentage of human error. After representing a literature review for the modeling of microencapsulation process in the first chapter, the methodology about how the process began and what parameters we followed to fulfill the requirement of the project. The effect of impeller speed 5000 rpm, 7500 rpm, 1000 rpm, 12000 rpm and 15000 rpm were determined on the number density functions and particle size reduction in the microencapsulation domain.Ansys. Fluent R2 2020 was used to model the experimental data. For the purpose of modeling the particle size distribution discrete method of population balance model is used. A total of five bins were selected to perform the size distribution analyze. The reason for selecting this small diameter range is the focus and accuracy of the solver. The bins should be more than enough to cover the distribution range and small enough to save computational time. Realizable k-e, Eulerian framework and appropriate bins initial values are used to predict the multiphase behavior. Under these conditions simulation converges very well and gives good agreement with the validation and experimental data.

DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS

  • HERNÁNDEZ CARLÓN, JUAN JESÚS: Proposal and Evaluation of Connectivity Solutions for Beyond 5G Radio Access Networks
    Author: HERNÁNDEZ CARLÓN, JUAN 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 SIGNAL THEORY AND COMMUNICATIONS
    Department: Department of Signal Theory and Communications (TSC)
    Mode: Normal
    Deposit date: 17/07/2024
    Deposit END date: 30/07/2024
    Thesis director: PEREZ ROMERO, JORGE | SALLENT ROIG, JOSE ORIOL
    Committee:
         PRESIDENT: VALDOVINOS BARDAJÍ, ANTONIO
         SECRETARI: UMBERT JULIANA, ANNA
         VOCAL: ADELANTADO FREIXER, FERRAN
    Thesis abstract: In the context of the fifth generation (5G) of mobile communications, the number of connected devices is expected to increase substantially compared to previous systems (e.g., LTE). Similarly, more stringent user requirements in terms of quality of service (QoS) are anticipated, beyond high data rates (e.g., latency, reliability, etc.). Providing these services adequately represents a challenge for mobile network operators in terms of network deployment and operation. Therefore, adopting strategies to ensure adequate connectivity conditions is critical for mobile network operators to successfully provide 5G and future (6G) services. In recent years, artificial intelligence (AI) has revolutionized mobile network design, deployment and management processes, thus driving the development of innovative solutions, sustained also on other technological advances such as software-defined networking (SDN), network functions virtualization (NFV). In fact, the impact of these technological tools is not limited to 5G systems, but will also extend to future generations such as 6G. In this context, this thesis addresses the challenge of proposing, developing and evaluating solutions at the Radio Access Network (RAN) level with the objective of ensuring optimal connectivity conditions and thus satisfying the QoS requirements of network users. Various techniques are used to achieve this goal, with special emphasis on the use of AI techniques. Firstly, the thesis presents a model to optimize Multi-connectivity (MC) in heterogeneous networks. MC is a key technology for managing high traffic densities and meeting stringent QoS requirements. Performing effective multi-connectivity management is challenging due to various factors such as propagation conditions, interference, loads of various cells, QoS metrics, etc. To address these challenges, the thesis presents a novel algorithm designed to dynamically split User Equipment (UE) traffic between different RATs and cells. The algorithm aims to satisfy QoS requirements while minimizing radio resource consumption in order to minimize the possibility of congestion in the involved cells. The proposed solution is based on the Deep Q-Network (DQN) algorithm. Through a training phase, the model learns an optimal traffic splitting policy to be applied to each UE. The policy adapts to the current conditions of both the UE and the network. This adaptive approach improves network performance by increasing user throughput while mitigating the risk of having cell congestion.Deepening into the problem of ensuring adequate network coverage and as a second contribution, the thesis presents a methodology for coverage optimization in 5G systems. This methodology is based on two main tasks: detection and resolution of coverage holes. It is introduced a Machine Learning based model capable of detecting and characterizing coverage holes by analyzing real network traffic data. A coverage hole becomes significant for network performance when there is a persistent presence of users in its region, as this is reflected in a degradation of both user experience and overall network performance. As a solution to the coverage holes, the thesis considers the integration of relays in order to extend network coverage; the solution comprises both fixed and mobile relays (i.e., UEs acting as relays). The solution based on fixed relays focuses on a functionality to mitigate coverage holes by strategically placing relays in order to improve network availability. On the other hand, it is proposed a solution to extend coverage based on Relay UEs (RUEs). To achieve this effectively, a DRL algorithm is proposed for the intelligent activation or deactivation of the RUEs. Overall, the proposed coverage optimization methodology has demonstrated its feasibility, leading to improved network and user performance.

DOCTORAL DEGREE IN SUSTAINABILITY

  • HIDROBO MORALES, JACQUELINE TATIANA: Metodología para el mapeo de conductores de innovación en empresas, con base en mapas de innovación
    Author: HIDROBO MORALES, JACQUELINE TATIANA
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN SUSTAINABILITY
    Department: University Research Institute for Sustainability Science and Technology (IS.UPC)
    Mode: Normal
    Deposit date: 22/07/2024
    Deposit END date: 04/09/2024
    Thesis director: GARCIA CARRILLO, AGUEDA
    Thesis abstract: Globally, the generation of innovation enables better economic, social, and environmental development for countries. Innovation mapping is a tool for visualizing internal and external innovation perspectives in the business environment. Although scientific works on innovation mapping mainly focus on developed economies such as the United States and Western Europe, innovation maps also play a significant role in fostering entrepreneurship and innovation in developing economies. There are no published scientific studies that comprehensively analyze the different existing tools and methods for innovation mapping or provide a structured methodology. The aim of this doctoral thesis is to provide companies with a method for innovation mapping based on the internal and external analysis of their innovation drivers. This method is also useful for mapping the most relevant drivers at the organizational and national levels.To achieve a comprehensive understanding of the evolution of scientific studies published on innovation mapping, a bibliometric analysis is conducted to extract and identify tools, methods, and drivers related to innovation and innovation mapping. The importance of innovation drivers in Ecuador during the years of significant entrepreneurship and innovation boost is identified and analyzed. This analysis is conducted through an exploratory systematic review. Statistical methods are used to perform an empirical analysis based on the Ecuadorian survey of Science, Technology, and Innovation Activities. The results expand the number of drivers from the bibliometric analysis and provide a better understanding of them in developing countries.Based on the results, a methodology for mapping innovation drivers in companies is developed, validated with experts, pilot tested with a Panamanian company, and the final proposal is made. The proposed methodology, MACI, uses a dimensionality reduction approach called Multiple Correspondence Analysis that allows mapping the innovation factors in a two-dimensional Euclidean space.The proposed MACI methodology is applied to four Panamanian companies from the perspective of relevant variables, human resources, innovation, financial aspect, and sustainability. The result is the innovation map of the studied companies and the identification of the most important variables for these companies to improve their innovation drivers.MACI provides a basis for a better understanding of the analyzed factors, not only at the company level but also at the organizational, regional, or national level. The findings of this doctoral thesis can help companies, business clusters, governments, and researchers to better understand the innovation drivers, promoting the formulation of strategies to foster R&D&I.

DOCTORAL DEGREE IN TEXTILE AND PAPER ENGINEERING

  • ALIEI, HESAM: Influence of household washing on the variation of the properties of intrinsic natural color organic cotton fabrics
    Author: ALIEI, HESAM
    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 TEXTILE AND PAPER ENGINEERING
    Department: Terrassa Institute of Textile Research and Industrial Cooperation (INTEXTER)
    Mode: Normal
    Deposit date: 22/07/2024
    Deposit END date: 04/09/2024
    Thesis director: CARRERA GALLISSÀ, ENRIQUE | CAYUELA MARIN, DIANA
    Committee:
         PRESIDENT: BONET ARACIL, MARÍA ÁNGELES
         SECRETARI: LIS ARIAS, MANUEL JOSÉ
         VOCAL: MANICH BOU, ALBERT M.
    Thesis abstract: Natural colored organic cotton fabrics gained considerable attention in recent years owing to due to their environmental friendliness and sustainability production. This imparts unique colors and patterns to the textiles. The colorimetric characteristics of these fabrics, including lightness and saturation, can be influenced by various factors being household washing one of them. To assess this effects, the colorimetric properties of knitted and woven fabrics were measured before and after 30 washing cycles with a skincare detergent with tap water at 40 ºC. The most significant difference in colorimetric properties was observed after the initial wash, highlighting the reduction in both parameters, lightness and saturation, after the first wash. Also, there was a notable colorimetric difference between the second wash and the fifth washout from the fifth wash onward, the changes were minimal. Additionally, the FTIR-ATR analysis of the extracts in petroleum ether and subsequently in ethanol of the NaCOC fabrics, before and after home washing, in conjunction with a comparison with shrinkage, demonstrated that the latter process is accountable for the darkening of the sample.Furthermore, the impact of various washing conditions on the fabric’s color change was investigated. Specifically, three detergents (Fox Fiber® Colorganic®, Klar, and Pure Nature), two types of water (tap and distilled), and three different temperatures (20, 40, and 60°C) were considered as variables. In this study, the effect of washing variables on the color and integrity of fabrics using colorimetric measurements was evaluated. The findings demonstrated that water hardness was the most influential variable in terms of color changes in fabrics.Overall, these findings highlight that household washing significantly affected the colorimetric properties of NaCOC fabrics, with the initial wash having the most substantial impact. The hardness of the water used in washing has been identified as a crucial factor in color changes, providing insights into the quality and color of natural-colored organic cotton textiles.Keywords: natural color, organic cotton, household washing, color change, colorimetric.
  • KOETZSCH, ANJA: Integrating Machine Learning Models to Optimize Nozzle Design and Enhance Airflow Dynamics in Airjet Spinning
    Author: KOETZSCH, ANJA
    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 TEXTILE AND PAPER ENGINEERING
    Department: Terrassa School of Industrial and Aeronautical Engineering (ETSEIAT)
    Mode: Normal
    Deposit date: 23/07/2024
    Deposit END date: 04/09/2024
    Thesis director: TORNERO GARCÍA, JOSÉ ANTONIO | WEIDE, THOMAS
    Committee:
         PRESIDENT: WEBER, MARCUS OLIVER
         SECRETARI: MANICH BOU, ALBERT M.
         VOCAL NO PRESENCIAL: KADOGLU, HUSEYIN
    Thesis abstract: This research delves into using Machine Learning techniques to enhance production efficiency in Airjet spinning. It focuses on understanding the factors that affect airflow by examining the components of a spinning nozzle, including the fiber inlet element, injector nozzle and spinning spindle. A prototype Airjet spinning nozzle was developed to evaluate the Intake Airflow and Airflow Rate, the basis for a simulation model. Five hundred-one data points were empirically gathered and analyzed to develop a computational model driven by Machine Learning algorithms.The investigation targets understanding the dynamics of airflows within the spinning nozzle, which plays a pivotal role in determining the properties and quality of the spun yarn. The cornerstone of this research lies in elucidating these complex interactions within the spinning nozzle, which, in turn, have far-reaching implications for the effectiveness and efficiency of the Airjet spinning process.The developed Machine Learning models, particularly CatBoost, effectively detected patterns within the data. These patterns revealed critical insights into how various factors impact yarn quality, including delivery speed, fiber material, and nozzle design. The study identified significant relationships between these factors and yarn properties, such as fiber loss, yarn evenness, breaking tenacity and elongation. However, neural network models, including Feedforward Neural Networks and autoencoders, faced challenges due to dataset variability, highlighting the need for more refined data.Findings highlight the significant impact of nozzle design and operational parameters on airflow dynamics and yarn quality. For instance, a smaller cross-sectional area of the fiber inlet improves yarn evenness and tenacity. At the same time, steeper angles and moderate diameters of the injector nozzle orifices enhance yarn evenness and strength. Additionally, shorter spindle tips and smaller inner diameters of the spinning spindle are associated with reduced fiber loss and improved yarn evenness.The thesis concludes by offering recommendations for optimizing Airjet spinning nozzle design based on the insights gleaned from the ML models.

DOCTORAL DEGREE IN URBANISM

  • RIBERA FUENTES, OLEGUER: Les muntanyes del carbó. La conquesta de la capçalera del Llobregat per proveir la ciutat
    Author: RIBERA FUENTES, OLEGUER
    Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
    Programme: DOCTORAL DEGREE IN URBANISM
    Department: Department of Urbanism, Territory and Landscape (DUTP)
    Mode: Normal
    Deposit date: 26/07/2024
    Deposit END date: 09/09/2024
    Thesis director: SABATE BEL, JOAQUIN | CORTELLARO, STEFANO
    Committee:
         PRESIDENT: FRANQUESA SANCHEZ, JORDI
         SECRETARI: ROCAMONDE LOURIDO, JAVIER
         VOCAL: PERARNAU LLORENÇ, JAUME
    Thesis abstract: This research analyses the transformation of the headwaters of the River Llobregat stemming from the impact of coal mining and industrialisation and understands these activities as the basis of the territory's current configuration. The study explores three main working hypotheses.The first maintains that coal mining has driven the transition from a system dedicated to rural activities to one dedicated to industrial activities, which is expressed in the appearance of settlements incorporating foreign populations along the communication routes.The second suggests that industrial activity defines the landscape of the headwaters of the Llobregat, with newly created centres of activity and the transformation of existing ones.The third affirms that coal mining introduced modernity to this territory, bringing new concepts in areas such as forms of construction, residential types, facilities and services.However, we defend that the industrial past can become an opportunity for revaluing the territory, with local development projects based on cultural resources.The hypotheses are grouped into three areas, which unfold over seven chapters that also address other secondary hypotheses. The analysis is developed chronologically, addressing the mining phenomenon from a stage prior to exploitation, during exploitation and finally from the perspective of the present day.
  • SOLA FONT, JOAN: Hipòtesis sobre una línia. Nuclis urbans i estacions a les línies interiors catalanes.
    Author: SOLA FONT, 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 URBANISM
    Department: Department of Urbanism, Territory and Landscape (DUTP)
    Mode: Normal
    Deposit date: 15/07/2024
    Deposit END date: 26/07/2024
    Thesis director: EIZAGUIRRE GARAITAGOITIA, FRANCISCO JAVIER | CROSAS ARMENGOL, CARLES
    Committee:
         PRESIDENT: RUBERT DE VENTOS, MARIA
         SECRETARI: MARTI CASANOVAS, MIQUEL
         VOCAL: SARDÀ FERRAN, JORDI
         VOCAL: GARCIA FONTAN, CRISTINA
         VOCAL: GÓMEZ ORDOÑEZ, JOSÉ LUIS
    Thesis abstract: "Hypothesis on a Line" analyses the impact that the construction of the railway has had on the urban centres along the interior lines of the Catalan network. The integration of a territorial mobility infrastructure into these fragile territories, with their seemingly modest urban heritage, has exerted a prolonged and significant influence from its inception to the present day.In the first part, the thesis focuses on the line from Granollers to Sant Joan de les Abadesses (GRN-SJA) and on eight of the urban centres it connects. This mining railway project, designed by Ildefons Cerdà, highlights the overlap of its ideological and theoretical foundation with its actual construction. Although initially projected for the extraction of coal in Ogassa, the arrival of the train had a significant impact on the towns, paradigmatically reflected in the urban morphology of each of the eight analysed localities. In the second part, the research extends the observation of the railway's impact to a selection of forty-four urban realities in various territories of the Catalan interior railway network.The thesis shows how the reaction of each urban centre is complementary, and sometimes contradictory to its own urban evolution. This evolution shifts from the initial optimism and confidence in progress generated by the railway, through its obsolescence as a communication system, to its current potential as a sustainable means of transport. The introduction of the railway as an external element with strong infrastructural conditions initially creates an urban tension with the station building, influenced by the physical distance and its symbolic value within the context of these towns. This situation brings about a first generation of urban elements: the station square, the station street, and the station neighbourhood. Subsequently, another set of elements will emerge, forming the 'other side' of the track, with facilities of wider territorial scope that contribute to enriching the syntax of contemporary railway urbanity.The set of urban reactions faces the geometric heritage of the railway with the traditional suburban nature of the surrounding urban fabrics. Thus, the local differences of each urban reality are linked by a territorial similarity that makes them common and comparable as part of the same line. The elements constructed over more than a century around this infrastructure display varying degrees of identity, transformation, and opportunity, acquiring greater complexity when viewed from the perspective of the entire railway space. The fragmentary urbanity of the railway invites to reflect on the different degrees of urban belonging and the hypothetical intensification of uses around the station and, by extension, throughout the entire railway urban space.Historically, the railway infrastructure has become an 'implant' that, in some cases, coexists with the urban fabric without generating significant effects around it. In other cases, it has created urban links or 'grafts' in its surroundings. Additionally, the continuity of the railway edges and their transversal capillarity with the nearby urban fabrics define an intermediate space with notable potential for transformation and improvement.Finally, the thesis seeks to demonstrate the ongoing relevance of the accumulated railway urbanity in some of the urban centres it connects, and its potential beyond the station area. From a trans-scalar perspective, it aims to highlight the Catalan interior railway lines as a heritage to be preserved and enhanced in the future.

Last update: 26/07/2024 04:30:29.