Author: HABIBI, SAEID
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: 16/12/2022
Reading date: 01/02/2023
Reading time: 10:30
Reading place: Enllaç públic per a la connexió a la videoconferència/Enlace público para la conexión a la videoconferencia/Public link for the videoconference:meet.google.com/snc-qkei-swt
Thesis director: PONS VALLADARES, ORIOL | PEÑA VILLAMIL, DIANA MARITZA
Committee:
     PRESIDENT: ARMENGOU ORÚS, JAUME
     SECRETARI: HAURIE IBARRA, LAIA
     VOCAL NO PRESENCIAL: SAELI, MANFREDI
Thesis abstract: Due to the fact that construction, maintenance, and operation of buildings consume almost 40% of global energy today, architects play a major role in the reduction of world energy consumption. Building¿s façades can have a significant and measurable impact on the economic, environmental, and social performances by edifices, and their retrofit is seen as a key solution to the problem of today¿s aging building stock. Concerning overheating and the potential loss of internal heat, transparent parts of the building façade have a large effect on the building¿s energy consumption. Within this context, the use of intelligent systems on architecture envelopes can fulfill contemporary demands as promising solutions regarding energy efficiency, emissions, or the degree of visual contact in building environments.In Spain, boom periods of construction combined with typical building styles of each period, have resulted in a large stock of aging educational buildings at risk of structural vacancy and obsolescence. Despite their lack of insulation, high air infiltration, and solar gain, many such edifices from the 1970s-1980s are still in use today. Moreover, the majority of today's buildings will still be in use in 2050 based on the Spanish edifices' annual replacement rate of 3% according to the European Commission.The main objective of this Ph.D. thesis is to analyze, develop and promote intelligent services to existing façades to optimize these buildings' economic, environmental, and social sustainability performances through a holistic and innovative sustainability assessment model.To do so, the first phases of this thesis, the author carried out a deep documental investigation on more than 800 research articles regarding intelligent façade systems, advancements in material engineering, user demands, automations, and their sustainability performance following the preferred reporting items for systematic reviews and meta-analyses reporting standards. Based on the results from preliminary investigations, different low-cost and environmental-friendly dynamic façades have been prototyped in the context of the Spanish public schools targeting pupils' academic progress through optimizing the lighting and thermal comfort levels. These prototypes have been developed by employing municipal solid waste materials during participatory workshops with school pupils. This concept is expected to promote awareness and better management of our society's critical waste generation by returning waste to the reusing cycle.From the data collected, researchers found that intelligent façade design and application result from a complex decision-making process. The cost and long-term nature of the investment mean that the façade decision is strategic. Accordingly, the next phase examined the actuality of intelligent façade projects in practice through conducting in-depth exploratory methodologies and tools for analyzing, evaluating, and designing among the incorporation of interdisciplinary experts in the topic. Finally, the last phase experimentally monitored and tested the developed prototypes and other test samples of various waste items.The findings show that the process of façade retrofit that fulfills the school building functioning, energy performance, emissions, costs, and appearance, requires the realm of the profession. The members involved in the retrofitting projects of public primary school buildings mainly had to make initial façade design decisions based on ideas resulting from cognition and drawing on experience. This thesis and its subsequent conceptual framework provide a new overview of waste-based construction materials and their introduction to developing intelligent façade technologies, through scientific indexes that can be useful for occupants, builders, architects, and policymakers to have a good understanding of the potential contributions that intelligent façades provide.

Author: LATORRE PÉREZ, FRANCISCO
Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
Programme: DOCTORAL DEGREE IN MARINE SCIENCES
Department: (DECA)
Mode: Normal
Deposit date: 29/09/2022
Reading date: 03/02/2023
Reading time: 11:00
Reading place: ETCECCPB_ Sala d'Actes de l'Institut de Ciències del Mar. Passeig Marítim de la Barceloneta, 37-49 08003 Barcelona
Thesis director: LOGARES HAURIE, RAMIRO ERNESTO | JAILLON, OLIVIER
Committee:
     PRESIDENT: GONZÁLEZ HERNÁNDEZ, JOSÉ MANUEL
     SECRETARI: GONZÁLEZ ACINAS, SILVIA
     VOCAL NO PRESENCIAL: DELMONT, TOM
Thesis abstract: There is a myriad of microorganisms on Earth contributing to global biogeochemical cycles. In the surface ocean, the smallest microbes (picoplankton) are responsible for an important fraction of the total atmospheric carbon and nitrogen fixation. The ocean picoplankton encompasses both prokaryotes (bacteria and archaea) and tiny unicellular eukaryotes (protists). Despite their overall importance for the functioning of the biosphere, many questions remain unanswered on their biogeography, population dynamics, interactions, and evolution. Answering these questions is essential in the context of global change, as alterations of the ocean microbiome could impact the function of multiple ecosystems. In this thesis, we aim at reducing the knowledge gap on the above topics through the application of High-Throughput Sequencing (HTS) and genomic approaches, using data collected during the circumglobal Tara Oceans and Malaspina-2010 expeditions, as well as at the Gulf of Maine (North Atlantic), and two Northwestern Mediterranean coastal microbial observatories (BBMO and SOLA stations). Chapters 1 and 2 are dedicated to a small protistan group of heterotrophic flagellates (HF): the Marine Stramenopiles (MAST)-4, relevant during picoplankton grazing and nutrient remineralization. Due to its widespread distribution and relatively high abundance, MAST-4 has become a target group of microbes to study HF. Unfortunately, MAST-4 remains uncultured. We investigated four evolutionary-related species of MAST-4 (species A, B, C, and E) by reconstructing their genomes with Single-Cell genomics data. In chapter 1, co-occurrence and biogeographic analyses in the surface global ocean indicated contrasting patterns driven by temperature. Although MAST-4 species were similar in terms of broad metabolic functions, they differed in the set of genes related to the food degradation machinery. We proposed that differential niche adaptation to temperature and prey type has promoted the evolutionary diversification in MAST-4. In chapter 2, we explore the intraspecies genomic divergence within each MAST-4 in the surface global ocean using metagenomic data. We found highly-differentiated populations among MAST-4A and C but lowly-differentiated populations in species B and E. Nevertheless, positive selection in specific genes pointed to niche adaptation to different ocean basins driven by fluctuating temperature and salinity conditions.Environmental factors also oscillate over time, but the effect they have over population remains a mystery. In chapter 3, we compared the genomic differentiation of 495 abundant prokaryotic metagenome-assembled genomes (MAGs) over 12 and 7 years in BBMO and SOLA stations, and across the surface global ocean. Our results suggested a stronger population differentiation at large-spatial scales, modulated by temperature and salinity, compared to long-temporal scales. However, underlying population structure was still detected in both time-series, with differential patterns of positive selection within the same genes. Although protists and prokaryotes are very different in terms of cellular structure, feeding, diversity, and reproduction, they are interconnected through biogeochemical and food web networks. In chapter 4, we developed an approach to infer potential interactions between these two groups based on the annotation of functional genes within Single-Amplified Genomes (SAGs). From a collection of over 3,000 SAGs, we corroborated associations (potential interactions) reported in previous works and inferred new ones involving uncultured marine protists that may hold important roles in ecosystem functioning.This thesis not only contributes to a better understanding of the biogeography, population dynamics, interactions, and evolution of marine microorganisms, but it also constitutes an expandable resource to test future hypotheses involving the ocean microbiome.

Author: WANG, YONGJIE
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: 11/01/2023
Reading date: pending
Reading time: pending
Reading place: pending
Thesis director: KONSTANTATOS, GERASIMOS
Committee:
     PRESIDENT: VAYNZOF, YANA
     SECRETARI: SAUCEDO SILVA, EDGARDO
     VOCAL: HOYE, ROBERT LIANQI ZHAO
Thesis abstract: Climate change and global energy demand urge the development of renewable energy sources for worldwide power supply. Photovoltaic devices that convert solar energy directly into electricity are the most promising, if not the only, technique to meet the requirements. Solution-processed solar cells are especially attractive due to their lightweight, low cost, and large-area mass manufacturing features. Among solution-processed materials, nanocrystals are one of the most promising, thanks to their material-property tunabilities, such as size, morphology, composition, electronic and optical properties, just to name a few. In the last decade, nanocrystal solar cells are mainly based on lead chalcogenide nanocrystals, although they face problems related to the toxicity of the element lead. Silver-bismuth sulfide nanocrystals are excellent substitutes for lead chalcogenides, thanks to their adequate bandgaps and extraordinarily high absorption coefficients. However, the energy conversion efficiency has lagged behind their toxic counterparts, mainly due to limited charge-carrier diffusion length and uncontrolled cation-disorder.In this thesis, we pinpoint the detrimental effects of cation inhomogeneity in ternary silver bismuth sulfide nanocrystals and further homogenize the cation-disorder by a facile post-annealing process, leading to absorption coefficients higher than any other commonly used solar materials over a wide range of 400 - 1000 nm. The cation-disorder configuration transition was further confirmed by the combination of ab initio density functional theory calculation and experimental material characterizations. Further optical modelling suggested a 30nm absorber layer possesses the potential for high Jsc up to 30 mA/cm2 and efficiency up to 26%. In addition to optical absorption enhancements, we also found elongated diffusion length up annealing, pointing to an anticipated high performance with ultrathin absorber. Ultrathin solar cells were thus fabricated with specially designed architecture and we achieved a record efficiency up to 9.17%, independently certified as 8.85% by Newport. The ultrathin solar cells also showed excellent stability under ambient conditions.In order to comply with mass manufacturing processes, we developed a solution-phase ligand-exchange procedure based on aqueous nanocrystal inks that enable single-step deposition of the active layer, reducing drastically the number of processing steps. Solar cell devices were built with the nanocrystal inks based on single-step deposition process and they showed a promising efficiency up to 7.3%, much higher than previous ink device record. In sum, we have achieved record-high performance, exceptionally stable AgBiS2 nanocrystal solar cells with both solid-state and solution-phase ligand-exchange procedures. This work sets a landmark for the development of environmentally friendly, low-temperature, solution-processed inorganic solar cells and opens a new field of engineering the atomic configuration of semiconductors as a means to achieve extraordinary optoelectronic properties.

Author: PLANA RIUS, FERRAN
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 AUTOMATIC CONTROL, ROBOTICS AND VISION
Department: Department of Automatic Control (ESAII)
Mode: Temporary seizure
Deposit date: 11/01/2023
Reading date: pending
Reading time: pending
Reading place: pending
Thesis director: MIRATS TUR, JOSEP MARIA | CASAS GUIX, MARC
Committee:
     PRESIDENT: ANDRÉS DOMÉNECH, IGNACIO
     SECRETARI: CEMBRANO GENNARI, M.GABRIELA ELENA
     VOCAL: LOPEZ PENA, ANTONIO MANUEL
Thesis abstract: Sewerage is a vital infrastructure for society¿s day-to-day life. Its maintenance is a priority and current European legislation increases the demand of a proper inspection. Being a complex access and dangerous environment, it complicates its inspection. Using teleoperated robots, a video of its interior is obtained. However, the operator report is highly subjective. The company INLOC Robotics SL offers a solution to make an automatic report using CCTV videos called SEWDEF. This thesis focuses on improving this system by focusing efforts on the integrated Convolutional Neural Networks (CNN).In this sense, we explore how CNNs work, putting efforts to understand how information is encoded within them. How they learn, what they learn and how to improve it. In the analysis carried out we realize that CNNs are not used to their full potential. There are several causes for that, from the lack of data to the CNN architecture used. However, in this thesis we aim to optimize the available data and CNN.In order to achieve this goal, the field of Curriculum Learning (CL) is explored. This field proves that by alternating the order in which images are fed to the training loop, results can be improved compared to a standard training regim. Exploring this idea, the Tracking Networks Self-Curriculum (TNSC) method is designed. It consists on training networks called Tracking Networks that help us find out in which order images are learned. This order can be used as a samples¿ difficulty measure and thus design a curriculum to train CNNs. Tested networks results improve, confirming that in the sewer field CL techniques are applicable. However, the method is complex and does not solve the situation for all the tested defects. For this reason the latent space is explored.The latent space is a high dimensional space that belongs to the CNN top layers, before the prediction layer. In this space we find encoded and compressed information about the input image characteristics. The thesis explores this space using Autoencoders (AE), self-supervised neural networks trained to reconstruct an input image after passing through an information bottleneck. Studying the latent space we can see that it contains relevant information, including about specific defects, that can be used in other tasks.Using the knowledge acquired, we develop a method called Supervised Latent Curriculum with SOM tree (SLCS). The method is based on performing a clustering of the latent space using the Self-Organizing Map (SOM) method. Instead of implementing a single SOM model, smaller models are used where at each iteration the clustering becomes more specialized through new models. This division allows us to create a difficulty measure for the samples that belong to the latent space. This measure can then be used to create curriculums that can be used to train CNNs. Results prove that the SLCS method is feasible. In most cases it outperforms the TNSC method and still has a lot of room for improvement.As a main conclusion we can draw that the two designed methods based on CL improve the INLOC Robotics SL SEWDEF system. It is also shown that altering the training order is able to improve the results of CNNs. In addition, a way has been found to use the latent space to design a difficulty measure.

Author: SALEHI, NAVID
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: Article-based thesis
Deposit date: 28/11/2022
Reading date: 08/02/2023
Reading time: 11:00
Reading place: EEBE - Campus Diagonal-Besòs. Sala polivalente del edificio A: A0.03. Dirección: Avda. Eduard Maristany, 16. 08019 - Barcelona.
Thesis director: MARTINEZ GARCIA, HERMINIO | VELASCO QUESADA, GUILLERMO
Committee:
     PRESIDENT: GUINJOAN GISPERT, FRANCISCO JUAN
     SECRETARI: EL AROUDI, ABDELALI
     VOCAL: ZUMEL VAQUERO, PABLO
Thesis abstract: This thesis is introduced the research performed on microgrid applications, especially in cooperative operating mode. The research is conducted considering two main challenging aspects of microgrid operation over the last years. The reliable and optimum operation of microgrids is surveyed by focusing on: energy management systems, specifically in collaborative microgridoperation and robust power electronics interfaces.This thesis presents a comprehensive review of optimization methods for individual and community microgrids. In addition, different control strategies applied in microgrid systems are studied. The potential pros and cons of various control strategies are analyzed, and the background studies bring brilliant and smart solutions for optimal control in a networked microgrid.A supervised and unsupervised learning clustering is developed in order to control a networked microgrid consisting of industrial, commercial, and residential microgrids. The clustering algorithms are performed based on the maximum load demand and operating reserve of the microgrid. Furthermore, a component size procedure for dispatchable units in a networked microgrid ispresented. The proposed algorithm evaluates the component size considering the operating reserve of microgrids. To diminish the adverse effect of component size reduction on microgrids¿ reliability, the proposed reduced factor is modified by the peak load and correlation of load profile.Optimal operation, new topology, and new control methods for various power electronics interfaces for microgrid applications are presented in the following. The optimal operation of the LLC resonant converter is investigated considering the load variation and switching frequency. Then, a modified cascaded high step-up Z-source DC-DC converter with high voltage gain and low voltagestress is proposed. Eventually, a novel control method for a single-phase Z-source inverter is presented. A feed-forward neural network predicts the forced response of the generalized predictive control to enhance the transient performance of the inverter.