Author: TABARES GIRALDO, YEISON ALEJANDRO
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: 07/07/2021
Reading date: 27/07/2021
Reading time: 10:00
Reading place: ETSETB - Sala de Juntes de l'edifici D4 - TSC - Campus Nord - meet.google.com/nap-qiea-wpb
Thesis director: PRAT GOMA, JOSEP JOAN
Committee:
     PRESIDENT: KILLEY, ROBERT
     SECRETARI: GENE BERNAUS, JOAN MANUEL
     VOCAL NO PRESENCIAL: FREUND, RONALD
Thesis abstract: Worldwide, the coherent technologies have revolutionized the optical communication systems, significantly increasing the capacity of the fiber channel owing to transmission of advanced modulation formats and effective mitigation of propagation impairments. However, the actual commercial solutions for long-haul core/backbone networks are still complex and costly, and therefore hardly feasible for deployment in optical access networks. In particular, the main limitations arise from the customer premises equipment whose cost, footprint and power consumption may be kept down. Thus, the optimal solutions for next generation coherent optical access are required to achieve high performance but at lower complexity and cost, since in the access scenario the cost-effectiveness takes more relevance over achieving the best system performance.The research described in this thesis primarily aims at the development of the customer equipment ¿namely the coherent transceiver¿ for a passive optical access network that implements the novel wavelength-to-the-user concept by serving hundreds of users (e.g., 256 users) with dedicated wavelengths allocated in ultra-narrow optical grid. The proposed access network features complexity-reduced coherent technologies by leveraging photonic integration, commercial low-cost lasers and optics, and consumer electronics. To this end, the thesis investigates on the main transmission impairments that affect signal integrity from source to destination in the access network, and proposes novel and enhanced mitigation strategies by either low-complexity digital signal processing or analog hardware design.The covered topics spread over both the optical transmitter and the coherent receiver subsystems. Simplified optical modulation is addressed by direct phase modulation of semiconductor lasers profiting from the laser chirp. Digital pre-equalization of non-ideal frequency response from electronic/photonic devices ¿such as lasers, amplifiers and data converters¿ is investigated, focusing on the tolerance to quantization noise from digital-to-analog converters with limited resolution. Hardware-efficient strategies for optical carrier recovery based on differential phase detection are explored in two scenarios: homodyne receivers aided by digital signal processing, or fully analog heterodyne receivers. Finally, to deal with the critical polarization matching in coherent systems, simplified architectures for polarization-independent coherent receivers using low-cost optics and simpler receiver front-end are investigated.

Author: BECERRA SÁNCHEZ, ENRIQUETA PATRICIA
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: 29/06/2021
Reading date: pending
Reading time: pending
Reading place: pending
Thesis director: REYES MUÑOZ, MARIA ANGELICA
Committee:
     PRESIDENT: GARCIA RUIZ, MIGUEL ANGEL
     SECRETARI: BARRADO MUXI, CRISTINA
     VOCAL NO PRESENCIAL: COSIO LEON, MARIA DE LOS ÁNGELES
Thesis abstract: Driving a vehicle is a complex activity exposed to continuous changes such as speed limits and vehicular traffic. Drivers require a high degree of concentration when performing this activity, increasing the amount of mental demand known as cognitive workload, causing vehicular accidents to the minimum negligence. In fact, human error is the leading contributing factor in over 90% of road accidents].In recent years, the subjects' cognitive workload levels while driving a vehicle have been predicted using subjective and vehicle performance tools. Other research has emphasized the use and analysis of physiological information, where electroencephalographic (EEG) signals are the most used to identify cognitive states due to their high precision. Although significant progress has been made in this area, these investigations have been based on traditional techniques or data analysis from a specific source due to the information's complexity. A new trend has been opened in the study of the internal behavior of subjects by implementing machine learning techniques to analyze information from various sources. However, there are still several challenges to face in this new line of research.This doctoral thesis presents a new model to predict the states of low and high cognitive workload of subjects when facing scenarios of driving a vehicle called GALoRSI-SVMRBF (Genetic Algorithms and Logistic Regression for the Structuring of Information-Support Vector Machine with Radial Basis Function Kernel). GALoRSI-SVMRBF is developed using machine learning algorithms based on information from EEG signals. Also, the information collected from NASA-TLX, instant online self-assessment and the error rate measure are implemented in the model.First, GALoRSI-SVMRBF proposes a new method for pattern recognition based on feature selection that combines statistical tests, genetic algorithms, and logistic regression. This method consists mainly of selecting an EEG dataset and exploring the information to identify the key features that recognize cognitive states. The selected data are defined as an index for pattern recognition and used to structure a new dataset capable of optimizing the model's learning and classification process.Second, the methodology and development of a classifier for the prediction model are presented, implementing machine learning algorithms. The classifier is developed mainly in two phases, defined as training and testing. Once the prediction model has been developed, this thesis presents the validation phase of GALoRSI-SVMRBF. The validation consists of evaluating the model's adaptability to new datasets, maintaining a high prediction rate. Finally, an analysis of the performance of GALoRSI-SVMRBF is presented. The objective is to know the model's scope and limitations, evaluating various performance metrics to find the optimal configuration for GALoRSI-SVMRBF.We found that GALoRSI-SVMRBF successfully predicts low and high cognitive workload of subjects while driving a vehicle. In general, it is observed that the model uses the information extracted from multiple EEG signals, reducing the original dataset by more than 50%, maximizing its predictive capacity, achieving a precision rate of >90% in the classification of the information. During this thesis, the experiments showed that obtaining a high percentage of prediction depends on several factors, from applying a useful collection technique data until the last step of the prediction model.

Author: CAMPOS TOBAJAS, JAVIER
Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
Programme: DOCTORAL DEGREE IN AGRI-FOOD TECHNOLOGY AND BIOTECHNOLOGY
Department: (DEAB)
Mode: Article-based thesis
Deposit date: 01/07/2021
Reading date: 28/07/2021
Reading time: 12:00
Reading place: ala Mercabarna de la EEABB. Ed. D4, Campus del Baix Llobregat de la Universitat Politècnica de Catalunya, C. Esteve Terradas 8, 08860 Castelldefels.
Thesis director: GIL MOYA, EMILIO
Committee:
     PRESIDENT: MARTÍNEZ CASANOVAS, JOSE ANTONIO
     SECRETARI: BROQUETAS IBARS, ANTONI
     VOCAL: DE CASTRO MEGÍAS, ANA ISABEL
Thesis abstract: The use of plant protection products (PPP) has become an essential tool in agriculture to achieve the minimum requirements of quality and quantity of food demanded by consumers. Moreover, due to its repeated use throughout the campaign, it is one of the most complex strategies in agriculture, due to the concern for achieving products free of pests and diseases, free of residues, and avoiding environmental risks.The recently published Farm to Fork Strategy aims at the difficult task of reducing the amount of hazardous pesticides used by 50 % by 2030. From the moment this strategy was published, it gained importance the implementation of improvements in application techniques to increase the effectiveness and efficiency of treatments. This is especially relevant in specialty crops such as orchards or vineyards, where the use of PPP is very high, compared with the case of field crops. In addition, this type of crops is characterised by a high degree of spatial variability in terms of the canopy structural characteristics, which makes it difficult to achieve a safe and effective application of pesticides.In this sense, variable rate application technology can reduce the effect of intra-plot variability, adjusting the volume rate to the canopy characteristics at each point, achieving a much more rational distribution of the plant protection product and more adjusted to the canopy than those carried out homogeneously. Currently, three types of variable rate application technology are known: 1) based on real-time sensors, 2) based on prescription maps, and 3) a combination of the two previous ones.Although variable rate application systems based on real-time sensors eliminate the need for prior knowledge of the crop, this technology has not been practically implemented in the viticulture sector. This contrasts with the adoption of vegetation maps acquired using remote sensing, which has been in commercial use for vineyard management for more than ten years. Among the management operations in which vegetation maps can have a greater impact is that of plant protection application, which is currently at an incipient level of implementation. For this reason, the main objective or this doctoral thesis, structured in three research publications, is to adapt and incorporate variable application technologies based on prescription maps to improve the efficacy and efficiency of treatments in the vineyard.The first research publication of the thesis was focused on the design, fine-tuning and field validation of a prototype of variable rate application based on prescription maps for vineyards. The article includes the whole process of variable map-based spraying, from the creation of the prescription map to obtaining the actual application map. The obtained results showed the possibility of saving up to 47.3 % of the amount of PPP concerning conventional treatment, demonstrating that it is possible to adapt, with the corresponding changes and adjustments, the available technology to the specific case of the vineyard.The main objective of the second research publication was the evaluation of the quality of the distribution of PPP on the vines and the evaluation of the biological efficacy of the applications during a complete campaign of treatments. During the research, the degree of adoption of the variable rate application system on a commercial farm and the possibility of implementing the technology in its annual treatment program were evaluated. A total of 28 treatments were carried out using the map based variable rate technology, obtaining in all treatments and vigour zones a coverage between 20 and 40 %, considered adequate values to guarantee pest/disease control in any spraying process. In terms of biological efficacy, the same levels of control were maintained as in the conventional treatments, and no significant differences were found between them. Although it was demonstrated that the variable rate application system allowed.

Author: TEJO OTERO, AITOR
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 MECHANICAL, FLUIDS AND AEROSPACE ENGINEERING
Department: Department of Mechanical Engineering (EM)
Mode: Temporary seizure
Deposit date: 25/06/2021
Reading date: 28/07/2021
Reading time: 10:30
Reading place: ETSEIB- Aula Capella Campus Sud UPC
Thesis director: BUJ CORRAL, IRENE | FENOLLOSA ARTÉS, FELIP
Committee:
     PRESIDENT: TRAVIESO RODRIGUEZ, JOSE ANTONIO
     SECRETARI: GÓMEZ GRAS, GIOVANNI
     VOCAL: MUNGUÍA VALENZUELA, JAVIER
Thesis abstract: Additive Manufacturing is the process of joining materials to make objects from a 3D model data, normally layer-upon-layer through series of some cross-sectional slices, as opposed to subtractive manufacturing technologies. In terms of themedical field, its expansion seems to have no end and can reach unexpected roads, and, in recent years, this progress has helped to minimize the health-related setbacks in our society. Different paths were opened in dental and hearing aids,biofabrication, tissue engineering and regenerative medicine, implants, the manufacture of surgical planning prototypes, etc.Doctors sometimes need to face complex surgeries that require a lot of time and this can lead to a higher likelihood of having a mishap. Additionally, until now, on many occasions, surgeons only had available the information that the DICOMsprovide, which might not be enough for preparing a surgery.That is why, the fabrication of 3D physical models is a useful method for improving the surgery skills of surgeons. Their use can be vital to help the doctor in understanding beforehand what is needed to be done in the operation for two reasons: (1)reducing operation time; and (2) decreasing the danger.Despite offering such a good improvement, there are relevant limitations with the prototypes manufactured recently: (1) a lack of prototypes which can mimic the corresponding tissues; (2) cost-effective AM technologies which are able to 3D print material that can reach the softness of soft living tissues. Among the seven categories of the AM technologies, four were used: vat-photopolymerization, powder bed fusion (PBF) for plastic parts, material extrusion (ME) and material jetting (MJ).The later one mentioned is the technology which have achieved s o far to 3D print prototypes that were ¿m ore mimetic than others ¿. But, it is a very expensive 3D printing process. Therefore, it was seen necessary to explore new roads to go onestep further and try to overcome the drawbacks of this AM technology by finding materials and 3D printing technologies which are both cost-effective and able to 3D print more realistic and cost-effective prototypes.In this way, a first approach by combining ME and PBF with indirect 3D printing is explored. Three different cases are introduced with the objective of reducing costs and achieving multi-materiality and softer parts: (1) two full-processes of indirect 3D printing of two hepatic cases using soft silicones; (2) a full-process of a neuroblastoma case using a hybrid multi-material 3D printer (ME by FFF and DIW), which is also presented; and (3) a full-process of a neuroblastoma case using a hybrid manufacturing, in other words, combining separately 3D printed in parts FFF and SLS. This approach was excellent for visualization as long as it is a multi-colour and multi-material 3D printed prototype. However, for hands-on training, this is more limited and, therefore, a necessity to keep working in the search of cost-accessible 3D printable materials: hydrogels and silicones.The characterization of materials is fulfilled and its correlation to the soft living tissues is done based on viscoelasticity (DMA), hardness (Shore hardness tests), cutting feeling (Warner-Bratzler shear test) and roughness . The results of the mimicking of the soft living tissues are explained, analyzed, and discussed with previous research studies. It was seen that hydrogels have similar properties to soft tissues in terms of hardness and viscoelasticity, but not for Warner-Bratzler shear test. Silicones, however, obtained disparate results: (1) commercial silicones are away from the range of soft tissues, and (2) self-synthetized silicones have better properties.It is confirmed that is possible to develop a 3D mimetic surgical planning prototype using indirect 3D printing, and this is done with a real case of a biliary tract rhabdomyosarcoma. The material used for the soft part is one the best materials showed in the analysis

Author: GIMENEZ IMIRIZALDU, ALEJANDRO
Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
Programme: DOCTORAL DEGREE IN URBANISM
Department: Department of Urbanism and Regional Planning (UOT)
Mode: Normal
Deposit date: 01/07/2021
Reading date: 29/07/2021
Reading time: 12:00
Reading place: Sala de Graus ETSAB - UPC Campus Sud - Av Diagonal 649, 08028 Barcelona
Thesis director: RUBERT DE VENTOS, MARIA | PARCERISA BUNDO, JOSEP
Committee:
     PRESIDENT: PEÑIN LLOBELL, ALBERTO
     SECRETARI: MÀRIA SERRANO, MARIA MAGDALENA
     VOCAL: GOULA, MARIA
     VOCAL: SARDÀ FERRAN, JORDI
     VOCAL: REINOSO BELLIDO, RAFAEL
Thesis abstract: In this thesis discontinuity is treated as an exception in the discourse or as a spelling license in the urban (con)text. In the first place, interruptions in urban routes are studied, the moments in which flows, movement, lines of the road on the plane stop, change or twist. Secondly, the gaze is raised to the plane of the facades and situations of blind urban dihedral, in which party walls and end walls are analyzed. The semantic potential of the city, the capacity to contain messages and the value, intention and meaning of some of them as revealing of discontinuity are also addressed here. Thirdly, exceptions as voids are observed in the built volume and, more precisely, in its residential matrix: expectant emptyness as trhedral apneas in the urban discourse. These three approaches are added in a narrative of increasing formal and functional complexity supported by a close look and direct experience of the city. The work is complemented with examples from other cities: Castelló, Bilbao, Donostia and Vigo, and contains as a sample a wining proposal for the Affordable Housing Challenge in New York City. The urban fabric of these cities is essentially continuous. Exceptions to this continuity of the urban landscape are rarely presented in its interior grids, in the friction between different fabrics, more frequently in its perimeters and in a striking way in the relationship with its maritime and river coastlines, in contact with its geological features, when mountains manifests themselves in a forceful way, next to the large mobility and collective transport infrastructures and in the contour of some large monofunctional areas of activity. They can be understood as aphorisms of an essentially coherent speech. Using the metaphor of grammatical structures, a cognitive strategy that assimilates the study of the city to that of language: morphogenetics (the genesis of embryonic communicative elements), semantics (meanings that grow complexity) and syntax (the ordering of those distinctive elements) three grammatical referents of great interest to the object of this task. This reading of the urban landscape as a discourse emphasizes the occasions in which its form presents interruptions, inflections or voids; discontinuities in its three material components (subdivision, urbanization, building) and in the three dimensions of space. Exceptions are sometimes loud. Some other times they are like the silences without which music would be just noise. A selection of 62 of the 600 sites from the preparatory material for the different editions of the public participation contest Racons Públics / Recantos Públicos / Hiriko Txokoak / Rincones Públicos is added to six case studies, a revisited of Mitgeres Barcelona de l¿oblit al projecte (2007) and Piso Piloto (2015) exhibitions, and multiple notes and references supported by twenty-five years of research experience and teaching commitment with the Barcelona School of Architecture. The work concludes by highlighting the value of the exception in relation to the strength of the urban system, analyzing its causes and consequences, critically evaluating some growth and transformation projects and pointing out future improvement strategies.