Author: ESKENATI, AMIR REZA
Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
Programme: DOCTORAL DEGREE IN STRUCTURAL ANALYSIS
Department: (DECA)
Mode: Normal
Deposit date: 28/04/2023
Reading date: 09/06/2023
Reading time: 12:00
Reading place: Sala de Conferències de l'edifici TR1de l'ESEIAAT (Terrassa)
Thesis director: BERNAT MASÓ, ERNEST
Committee:
     PRESIDENT: BARRIS PEÑA, CRISTINA
     SECRETARI: BONADA BO, JORDI
     VOCAL: MARCE NOGUE, JORDI
Thesis abstract: Themost common composite materials for strengthening building structures are divided into twodif ferent types based on the matrix¿s composition, organics (polymers) or inorganics (cement, lime). Thehybrid structures presented here in for the first time are made of two components; fabric reinforcedcementitious matrix (FRCM) composite and pultruded fib er reinforced polymer (FRP) profiles.The main idea of the experimental research was to characterize the individual materials and the structuralbehavior of FRP profiles FRCM hybrid superficial elements. The experimental campaigns and numericalstudi es consist of three parts; materials individual characterization, connection between materials (FRPFRP, FRP Mesh and Mesh Mortar) and characterization of the full hybrid superficial elements using thebest combination from the previous tests.In terms ofFRP FRP connection tests, the mechanical behavior of adhesively and bolted joints forpultruded Glass FRP (GFRP) profiles has been experimentally addressed and numerically modeled. A totalof nine specimens with different configurations (bolted joints, adh esive joints, web joints, web and flangejoints, and two different angles between profiles) were fabricated and tested, extending the availablepublished information. The novelty of the research is in the direct comparison of joint technologies (boltedvs. adhesive), joint configuration (web vs. flange + web) and angles between profiles in a comprehensiveway. Plates for flange joints were fabricated with carbon fiber FRP. Experimental results indicate thatadding the bolted flange connection allowed for a slight increase of the load bearing capacity (up to 15%)but a significant increase in the stiffness (between 2 and 7 times). Adhesively connections only reached25% of the expected shear strength according to the adhesive producer if comparing the numericallycalculated shear strength at the failure time with the shear strength capacity of the adhesive.In FRP Mesh connection tests part, four specimens with different materials (resin connection, boltedconnection) were made and tested. Moreover, the effect of high temperature was evaluated. To sum up,the best connector is resin connection and high temperature has low effect on the resistance of thespecimen with resin connector.Regarding to the MeshMortar connection tests, four specimens were made with FRCM (2 types of mortar)using glass fiber mesh and tested under tensile configuration in order to investig ate the behavior of themesh and mortar. Glass fiber mesh led to increase ultimate load and strain. Two types of mortar wereused; an autolevelling one and a repair one. Axton mortar had better behavior under tensile test incomparison with Sika.The main idea of full hybrid panels was to extend this approach by replacing the concrete with a fabricreinforced cementitious matrix (FRCM) composite, resulting in a combination of composite materials. Themain aim was to characterize the structural behavior of fiber reinforced polymer (FRP) profiles and FRCMhybrid superficial elements. Two different prototypes of the hybrid superficial structural typology weretested to cover bidimensional ( HP1) and three dimensional (HP2) application cases of the proposedtechnology. A finite element model was implemented, calibrated, and validated by comparing numericaldata with experimental results of the two prototypes. The output was a validated model that correctlycaptured the characteristic response of the proposed technology, which consisted of changing thestructural response from a stiff plat e configuration to a membrane type due to cracking of the FRCMcomposite part of the full solution. The suggested numerical model adequately reflected the experimentalresponse and proved valuable for understanding and explaining the resistive processes es tablished alongthis complicated FRP FRCM hybrid structure.

Author: PEREA ROBLES, RAFAEL
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: 23/03/2023
Reading date: 09/06/2023
Reading time: 11:00
Reading place: Edificio C4-128-B, EETAC, Esteve Terradas, 7, Campus UPC, 08860.-Castelldefels (Barcelona)
Thesis director: MATEU MATEU, JORDI | COLLADO GOMEZ, JUAN CARLOS
Committee:
     PRESIDENT: AIGNER, ROBERT
     SECRETARI: GILABERT PINAL, PERE LLUIS
     VOCAL: VILLANUEVA TORRIJO, LUIS GUILLERMO
Thesis abstract: During the last years, electro-acoustic technology has been a key factor in the development of portable devices thanks to its high performance and very compact filtering structures. Such a technology has enabled the inclusion of several systems and standards in a single device.Specifically, with the introduction of the new 5G and the carrier aggregation techniques, today's handset devices might have more than 50 RF filters to support usage in countries across the world. As a matter of fact, the expectation is that these numbers increase over the future.The new generation of communication standards calls for very wide bandwidths of operation and higher data rates. These requirements impose the development of ultra-wideband filters that can provide outstanding performance in terms of low loss, high rejection and multifrequency operability in the smallest possible footprint.Ladder filter topology has been the preferred one for the development of filters in the past generations of standards, since it provides very high selective filters with low insertion loss levels. However, the maximum achievable bandwidth is limited to the electro-acoustic coupling coefficient, the position of the transmission zeros depends on the resonant frequencies of the resonators and itsout-of-band behavior is determined by the capacitance ratio between resonators. These shortcomings could become a bottleneckfor the forthcoming stringent specifications.In a recent work, a new transversal topology has been introduced that offers a high degree of flexibility in the design of acoustic filters and it has proven to solve some of the limitations of the ladder topology. Nevertheless, its differential behavior requires of a balun stage to properly work. Moreover, some circuital transformations that are carried out in the current synthesis procedures have some limitations when ultra-wideband filters are targeted.The aim of this work is to provide novel solutions that overcome the existing limitation of the current filter topologies in the state-of-the-art. Thereby, contributing with filter synthesis procedures that provide filters with larger relative bandwidths, higher rejection and a higher degree of miniaturization. On the one hand, a new synthesis procedure based on acoustic transversal filters for ultra-wideband filters is presented which culminates with the manufacturing of a real prototype with 24 % of fractional bandwidth operating at the N77 band. Moreover, advanced filtering responses based on multifiltering schemes for transversal topology are also analyzed. On the other hand, the concept of transversal topology is applied to acoustically-coupled structures: Stacked Crystal Filters and Coupled Resonator Filters (CRF). The extension of the transversal topology to these two configurations will allow to remove the balun stage of the convential acoustic transversal filters and also to provide a higher level of miniaturization. Finally, a new synthesis procedure for the development of fourth-order acoustic CRF structures from the mathematical formulation to the real layer configuration is presented. This might be a key factor for the development of the next generation of filters, since it could be mixedwith ladder and transversal topologies and give rise to advanced responses with improved performance, as well as with a further degree of miniaturization.

Author: SELSELEH JONBAN, MANSOUR
Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
Programme: DOCTORAL DEGREE IN ELECTRONIC ENGINEERING
Department: Department of Electronic Engineering (EEL)
Mode: Normal
Deposit date: 17/03/2023
Reading date: 09/06/2023
Reading time: 11:00
Reading place: ESEIAAT, Aula 334 Edifici GAIA (TR14), Campus Terrassa
Thesis director: ROMERAL MARTINEZ, JOSE LUIS
Committee:
     PRESIDENT: SHAHPARASTI, MAHDI
     SECRETARI: DELGADO PRIETO, MIGUEL
     VOCAL: ABDOLLAHI, MOSTAFA
Thesis abstract: Nowadays, distributed energy resources are widely used to supply demand in micro grids especially in green buildings. These resources are usually connected by using power electronic converters, which act as actuators, to the system and make it possible to inject desired active and reactive power, as determined by smart controllers. The overall performance of a converter in such system depends on the stability and robustness of the control techniques. This thesis presents two bottom­up smart control approaches to manage energy in DC microgrids (MG) that split the demand among several generators. Firstly, an energy management system (EMS) based on multi-agent system (MAS) controllers is developed to manage energy, control the '.<lltage and create balance between supply and demand in the system with the aim of supporting the reliability charactenstic. In the proposed approach, a reconfigured hierarchical algorithm is implemented to control interaction of agents, where a CAN bus is used to provide communication among them. This framework has the ability to control system, even if a failure appears into decision unit The second research approach presents an energy management system based on multi-agent system under the supervision of a smart contract with a bottom-up approach for a grid connected DC micro-grid that is equipped with solar photovoltaic panels (PV), wind turbine (WT) and micro-turbine (MT) and energy storage (BES). In the presented approach, each unit controls and manages through a distributed decision structure. The BES agent is managed by an intelligent structure based on a reinforcement learning model. Since charging and discharging the battery is a stepwise process, in this research, a Markov decision process is trained by using a Q-learning algorithm. The rest of the agents are controlled and managed by heuristic algorithms. To create interaction and coordination among agents, a tendering process is used wherein each agent under its supervised control structure presents its offer to the tendered item at each time period The tendering organization allocates the requested power through first price sealed-bid algorithm between bidders to optimize energy cost in the MG. The two proposed approaches present online intelligent systems that can guarantee fault-tolerance, stability and reliability in the MG especially in green houses and smart cities, respectively. Various scientific papers have been published or are currently under review that can validate the achieved objectives and guarantee the quality of the thesis.

Author: CRUZ DE LA CRUZ, STALIN LEONEL
Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
Programme: DOCTORAL DEGREE IN COMPUTER ARCHITECTURE
Department: (DAC)
Mode: Normal
Deposit date: 16/05/2023
Reading date: pending
Reading time: pending
Reading place: pending
Thesis director: TOUS LIESA, RUBÉN | OTERO CALVIÑO, BEATRIZ
Committee:
     PRESIDENT: MARTI ESCALE, RAMON
     SECRETARI: CANAL CORRETGER, RAMON
     VOCAL: CARRERAS COCH, ANNA
Thesis abstract: Deep learning techniques have an enormous impact on the state-of-the-art in many fields, such as computer vision, natural language processing, audio analysis and synthesis, and many others. The increasing computing power, the increasing amount of available data, and the algorithms' evolution foster this impact. On the one hand, this thesis applies Deep Learning techniques to large parallel systems to train and validate Neural Networks models for different applications. First, a technology stack to enable the distribution of deep learning workloads on a traditional High Performance Computing (HPC) setup such as the MareNostrum supercomputer is designed and evaluated. The key element of the deployed layered architecture is Apache Spark, which enables to isolate machine-learning applications from the particularities of the infrastructure, in this case, the MareNostrum supercomputer. The deployment of Spark-enabled clusters over MareNostrum is not trivial and it has done with the help of Spark4MN, a custom interoperability layer. On top of this stack (Marenostrum, Spark4MN and Spark) a deep learning specific layer is placed, DL4J. The goal is to provide insights into how the job configuration on a traditional HPC setup can be optimized to efficiently run this kind of workloads. The derived conclusions should be useful to guide similarly complex deployments in the future. Second, in a derived work, a use case is explored. We design and train deep CNNs for annotating and filtering images from social media (Instagram and Twitter). We capture the images in real-time and processes them by multiple CNNs that automatically enrich their metadata with tags that describe their visual content and also how they fit the visual identity of a brand (VBI) . With this method, we have trained VBI classifiers for more than 10 real brands and more than 100 classifiers for generic description of social media images. On the other hand, this thesis applies Deep Learning techniques on a computer cluster to train multiple NN configurations employed for earthquake detection and location. First, we develop a new method called UPC-UCV, consisting of applying a convolutional neural network to single-station 3-channel waveforms for P-wave earthquake detection and source region estimation in north-central Venezuela. This part includes the build of a new dataset, CARABOBO, that has been made public for reproducibility and benchmarking purposes. Both the UPC-UCV network and the CARABOBO dataset are the first developed for this geographic region. The method obtains better results than the State of the Art (SOA), yielding higher detection accuracy (13.3 percentage point increase) for the new target seismicity. UPC-UCV achieves a 95.27% detection accuracy. Second, in a derived work, we focus on the source region estimation problem. Source region estimation is a relaxed version of the earthquake location problem that consists on, first, partitioning a study area into K geographic subdivisions and, second, attempting to determine to which one the earthquake epicenter belongs. In the previous work, we performed the partitioning with k-means. In this part, we experiment with a geographical subdivision provided by a seismologist, consisting on irregular polygons covering the main seismic faults of Venezuela. While the obtained results for a small number of geographic subdivisions are not better than the ones obtained with k-means clustering, the good results obtained with a large number of subdivisions (91.78% with K::;:; 10) outperform the k-means approach (66.10%). It should be noted that to obtain these results, the use of spatial-based techniques significantly improved the final model. This confirms the target hypothesis that the source region estimation accuracy is significantly increased if the geographical partitioning is performed considering the regional geophysical characteristics such as the tectonic plate boundaries.

Author: IVANOVA, ANZHELIKA
Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
Programme: DOCTORAL DEGREE IN STATISTICS AND OPERATIONS RESEARCH
Department: Department of Statistics and Operations Research (EIO)
Mode: Normal
Deposit date: 16/05/2023
Reading date: pending
Reading time: pending
Reading place: pending
Thesis director: CORCHERO GARCIA, CRISTINA | DOMÍNGUEZ GARCÍA, JOSÉ LUIS
Committee:
     PRESIDENT: KRKOLEVA MATESKA, ALEKSANDRA
     SECRETARI: VILLAFÁFILA ROBLES, ROBERTO
     VOCAL: COMECH MORENO, MARIA PAZ
Thesis abstract: The smart grid concept in distribution networks has risen due to the ICT trend, with the transformation of the network into an active one, incorporating many different smart grid technologies. One of the main components that can allow this to happen is the monitoring system that includes measurement devices, sensors and automation. Due to the topological and electrical characteristics of the distribution networks, the need to reduce costs presents an issue and sensors and automation devices cannot be placed at each point of the network. This causes the network to have unmonitored parts, which leads to the need to optimize the placement of sensors (Phasor Measurement Units) and perform state estimation to ensure the most optimal monitoring and control scheme. The placement of measurement devices such as the PMUs, improves observability and controllability of the distribution network and enables new features of grid operation. These new features should make the network resilient so that the service disruption for the end users after a contingency event is minimized as much as possible. This can be achieved through two main methods, network reconfiguration by modifying the electricity path to isolate the faulty line or equipment, or by allowing islanded/disconnected operation of some parts of the network. The distributed generation aids the islanded operation by providing the needed power supply in the islanded parts of the distribution network. Another important aspect for the Distribution System Operators when reconfiguring the grid to deal with faults is to maintain observability of the network. This means that in following an intentional islanding process, it is important to have monitoring devices in each island, so that the operators do not lose the monitoring and controlling capabilities within the created islands. The approach to solve the previously explained problems depends on the type of distribution network. These can vary in topology depending on the voltage level. Medium voltage distribution networks have predominantly weakly-meshed structures that can be operated in radial mode, whereas low voltage distribution networks have radial structures. This difference in topologies means two different research directions. Therefore, the research in this thesis focuses on the medium-voltage distribution networks. The presented seemingly different problems are strongly interconnected within an active distribution network. As part of this work, the lack of an integrated approach to solving these complex problems has been identified, especially within medium-voltage networks. Therefore, the main contribution of this thesis is to present integrated approaches to solving these problems by: analysing the different solution techniques and testing the relevant ones on the chosen networks, developing processes to assess the interdependence of the different solution techniques and developing a new tool that helps the intentional islanding process after a fault that takes into account the observability of the formed islands. Keywords: optimal PMU placement, state estimation, intentional islanding, medium voltage networks