Author: CUADRADO GUEVARA, MARLYN DAYANA
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: 22/10/2020
Reading date: 30/11/2020
Reading time: 12:00
Reading place: FME: Videoconferència per COVID-19: https://meet.google.com/nsy-skve-ska
Thesis director: HEREDIA CERVERA, FRANCISCO JAVIER
Committee:
     PRESIDENT: RAMALHINHO DIAS LOURENÇO, HELENA
     SECRETARI: CASTRO PÉREZ, JORDI
     VOCAL: MORALES ESPAÑA, GERMAN ANDRES
Thesis abstract: The presence of renewables in energy systems optimization have generated a high level of uncertainty in the data, which has led to a need for applying stochastic optimization to modelling problems with this characteristic. The method followed in this thesis is multistage Stochastic Programming (MSP). Central to MSP is the idea of representing uncertainty (which, in this case, is modelled with a stochastic process) using scenario trees. In this thesis, we developed a methodology that starts with available historical data; generates a set of scenarios for each random variable of the MSP model; define individual scenarios that are used to build the initial stochastic process (as a fan or an initial scenario tree); and builds the final scenario trees that are the approximation of the stochastic process. The methodology proposes consists of two phases. In the first phase, we developed a procedure similar to Muñoz et al. (2013), with the difference being that the VAR models are used to predict the next day for each random parameter of the MSP models. In the second phase, we build scenario trees from the Forward Tree Construction Algorithm(FTCA), developed by Heitsch and Römisch (2009a); and an adapted version of DynamicTree Generation with a Flexible Bushiness Algorithm (DTGFBA), developed by Pflugand Pichler (2014, 2015). This methodology was used to generate scenario trees for two MSP models. A first model, Multistage Stochastic Wind Battery Virtual Power Plantmodel (MSWBVPP model) and to a second model, which is the Multistage StochasticOptimal Operation of Distribution Networks model (MSOODN model). We developed extensive computational experiments for the MSWBVPP model and generated scenario trees with real data, which were based on MIBEL prices and wind power generation of the real wind farm called Espina, located in Spain. For the MSOODN model, we obtained scenario trees by also using real data from the power load provided by FEEC-UNICAMP and photovoltaic generation of a distribution grid located in Brazil. The results show that the scenario tree generation methodology proposed in this thesis can obtain suitable scenario trees for each MSP model. In addition, results were obtained for the model using the scenario trees as input data. In the case of the MSWBVPP model, we solved three different case studies corresponding to three different hypotheses on the virtual power plant¿s participation in electricity markets. In the case of the MSOODN model, two test cases were solved, with the results indicating that the EDN satisfied the limits imposed for each test case. Furthermore, the BESS case gave good results when taking into account the uncertainty in the model. Finally, the MSWBVPP model was used to study the relative performance of the FTCA and DTGFBA scenario trees, specifically by analyzing the value of the stochastic solution for the 366 daily optimal bidding problems. To this end, a variation of the classical VSS (the so-called ¿Forecasted Value of the Stochastic Solution¿, FVSS) was defined and used together with the classical VSS.

Author: LÓPEZ ORDÓÑEZ, CARLOS FERNANDO
Thesis file: (contact the Doctoral School to confirm you have a valid doctoral degree and to get the link to the thesis)
Programme: DOCTORAL DEGREE IN ARCHITECTURE, ENERGY AND ENVIRONMENT
Department: Department of Architectural Technology (TA)
Mode: Normal
Deposit date: 06/11/2020
Reading date: 30/11/2020
Reading time: 16:30
Reading place: Sala de Graus ETSAB - UPC Campus Sud - Av Diagonal 649 - videoconferència: meet.google.com/zwu-tdbo-fko
Thesis director: CRESPO CABILLO, ISABEL | ROSET CALZADA, JAIME
Committee:
     PRESIDENT: OCHOA DE LA TORRE, JOSÉ MANUEL
     SECRETARI: ALONSO MONTOLÍO, CARLOS
     VOCAL NO PRESENCIAL: MORGANTI, MICHELE
Thesis abstract: By 2050, the world's population will have doubled and will be mainly urban. This perspective generates the need to think about the present and the future of cities, especially those located in mid-latitudes, where a large part of that population accumulates. Many of these cities are in regions with hot semi-arid and hot-dry climates.Traditionally, desert cities were designed in compact shapes in response to various climatic factors. Today, these cities have adopted the dispersed city model, driven by car use, the emergence of cooling systems, and a steady decline in energy costs. This form of growth raises a series of problems from an environmental point of view: poor habitability of the public space, long distances, an elevated land use, high demand for cooling.The goal of this thesis is to evaluate the energy repercussions of the increase in urban density in dispersed and low-density cities with a hot-dry climate in the northwestern region of Mexico. The city of Hermosillo in Sonora, a medium-sized city in expansion, is taken as a case study. This thesis analyzes the effects of urban densification on three different scales: city, neighborhood, and building.Based on a city-scale cartographic analysis, this thesis shows that Hermosillo presents a dispersed pattern of low-density growth with two main characteristics: low centrality and high fragmentation. The low centrality is due to the loss of population and economic weight of the urban center in favor of the periphery. The urban fragmentation is a result of the existence of a large number of vacant lots (35% of the urban area). Therefore, two urban strategies are identified and could be followed to slow down the growth of the urban area: the infill of vacant lots and the densification of existing fabrics (stacking) for the creation of high-density sub-centers.The historic center of Hermosillo is selected to carry out the analysis on a neighborhood scale. The impact that a densification process of an existing urban fabric has on the habitability of the urban space is assessed. Currently, this fabric has a high pedestrian potential, but low population and building density, and high levels of solar radiation. In this thesis, the study area is rethought through a densification process employing the mixed-use lot and the stacking of houses. It is shown that by following the current regulations is possible to achieve building density values similar to those of urban centers and tissue of cities with compact morphology. Also, by allowing an increase in density allows achieving streets with an aspect ratio of around h/w= 1, a ratio that, at this latitude, permits the creation of "shadow corridors" spaces protected from radiation.Finally, the impact of stacking on energy performance at the building scale is analyzed using dynamic thermal simulations. To this end, this thesis compares the thermal behavior of free-running homes and the energy demand for cooling during the hot season of isolated single-family homes and multi-family homes in height. The conclusion is that the higher the stacking level, the better the thermal and energy performance. Furthermore, this study demonstrates that in homes without refrigeration, the use of solar protection on windows achieves a slightly superior improvement than that of thermal insulation.Therefore, this thesis allows us to demonstrate that an increase in density (building and population) has advantages at different scales, especially in cities with a hot-desert climate. Stacking allows the creation of shade in the public space and, at the same time, an improvement in the internal energy consumption of refrigerated homes.

Author: MATEU MATEUS, MARC
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: 21/10/2020
Reading date: 01/12/2020
Reading time: 10:00
Reading place: ETSEB: aula de teleensenyament del B3. VIDEOCONFERÈNCIA PER covid-19 https://meet.google.com/qjg-qmzv-zxe
Thesis director: RAMOS CASTRO, JUAN JOSE | FERNANDEZ CHIMENO, MIREYA
Committee:
     PRESIDENT: VIDAL MARTÍNEZ, MARIA NIEVES
     SECRETARI: ALONSO LÓPEZ, JOAN FRANCESC
     VOCAL: JAUREGUI TELLERIA, RICARDO IGNACIO
Thesis abstract: Due to the growing popularity of video-based methods for physiological signal measurement, and taking into account the technological advancements of these type of devices, this work proposes a series of new novel methods to obtain the respiratory signal from a distance, based on video analysis. This thesis aims to improve the state of the art video methods for respiratory measurement, more specifically, by presenting methods that can be used to obtain respiratory variability or perform respiratory rhythm measurements. Moreover, this thesis also aims to present a new implementation of a time-frequency signal processing technique, to improve its computational efficiency when applied to the respiratory signals.In this document a first approach to video-based methods for respiratory signal measurement is performed, to assert the feasibility of using a consumer-grade camera, not only to measure the mean respiratory rate or frequency, but to assert if this hardware could be used to acquire the raw respiratory signal and the respiratory rhythm as well. In this regard a new video-based method was introduced that measures the respiratory signal of a subject at a distance, with the aid of a custom pattern placed on the thorax of the subject.Given the results from the first video-based method, a more broad approach was taken by comparing three different types of video hardware, with the aim to characterise if they could be used for respiratory signal acquisition and respiratory variability measurements. The comparative analysis was performed in terms of instantaneous frequency, as it allowed to characterise the methods in terms of respiratory variability and to compare them in the same terms with the reference method.Subsequently, and due to the previous obtained results, a new method was proposed using a stereo depth camera with the aim to tackle the limitations of the previous study. The proposed method uses an hybrid architecture were the synchronized infrared frame and depth point-cloud from the same camera are acquired. The infrared frame is used to detect the movements of the subject inside the scene, and to recompute on demand a region of interest to obtain the respiratory signal from the depth point-cloud. Furthermore, in this study an opportunistic approach is taken in order to process all the obtained data, as it is also the aim of this study to verify if using a more realistic approach to respiratory signal analysis in real-life conditions, would influence the respiratory rhythm measurement. Even though the depth camera method proved reliable in terms of respiratory rhythm measurement, the opportunistic approach relied on visual inspection of the obtained respiratory signal to properly define each piece. For this reason, a quality indicator had to be proposed that could objectively identify whenever a respiratory signal contained errors. Furthermore, from the idea to characterise the movements of a subject, and by changing the measuring point from a frontal to a lateral perspective to avoid most of the occlusions, a new method based on obtaining the movement of the thoraco-abdominal region using dense optical flow was proposed. This method makes us of the phase of the optical flow to obtain the respiratory signal of the subject, while using the modulus to compute a quality index.Finally, regarding the different signal processing methods used in this thesis to obtain the instantaneous frequency, there were none that could perform in real-time, making the analysis of the respiratory variability not possible in real-life systems where the signals have to be processed in a sample by sample basis. For this reason, as a final chapter a new implementation of the synchrosqueezing transform for time-frequency analysis in real-time is proposed, with the aim to provide a new tool for non-contact methods to obtain the variability of the respiratory signal in real-time.

Author: NANDY, BIPLOB KUMAR
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: 28/10/2020
Reading date: 02/12/2020
Reading time: 15:00
Reading place: ICFO: Videoconferència per COVID-19 http://s.ic.fo/Qy6AN
Thesis director: EBRAHIM-ZADEH, MAJID | SUDDAPALI, CHAITANYA KUMAR
Committee:
     PRESIDENT: AGNESI, ANTONIANGELO
     SECRETARI: COJOCARU, CRINA MARIA
     VOCAL: LAURELL, FREDRIK
Thesis abstract: Tunable narrow-linewidth and broadband laser sources in the mid-infrared (mid-IR) wavelength range are extremely desirable in all time scales for their several useful applications in spectroscopy, imaging, optical communication and medical sciences to name a few. The one very important application of high-power tunable narrow-linewidth mid-IR laser sources in the 2 µm wavelength range is the ability to pump cascaded mid-IR optical parametric oscillators (OPO) for generating tunable wavelengths beyond 4 µm using semiconductor nonlinear crystals such as ZnGeP2 (ZGP) or orientation patterned GaAs (OP-GaAs). These crystals have very good linear and nonlinear optical properties along with good transparency beyond 4 µm wavelengths unlike oxide-based materials such as MgO:PPLN which have strong multi phonon absorption beyond 4 µm wavelengths. However, both ZGP and OP-GaAs cannot be pumped by commercially available 1 µm lasers due to linear and nonlinear absorptions below~2 µm wavelengths. In this thesis, we have demonstrated some very useful high-power narrow linewidth tunable 2 µm nanosecond and picosecond high-repetition-rate sources with very good spatial beam qualities. We have further demon strated a picosecond mid-IR idler-resonant MgO:PPLN based OPO with intra-cavity second-harmonic-generation (SHG). This helps in covering the essential wavelength gap between 1.064 µm and 1.45 µm when pumped by Yb- ber laser at 1.064 µm. This wavelength gap is generally not covered by MgO:PPLN based SROs that are signal resonant due to the material transparency of MgO:PPLN which doesn't allow the idler wave to go above ~4 µm wavelength, thereby restricting the signal wave from reaching below ~1.45 µm.Due to the requirement of synchronous pumping, the OPOs typically tend to be relatively bulky and of large size, which can restrict its practical utility in space-constrained applications. We address this challenge by demonstrating a compact picosecond high-repetition rate singly resonant (SRO) with intracavity-mirror-retro-re ector ber (IMRF) that enables two-fold reduction in the form-factor. This IMRF OPO demonstrates a high wavelength tunability from~1.45 µm to~4 µm with high spectral brightness and exceptionally good output beam quality. In our attempt to further reduce the size and complexity of nonlinear frequency conversion sources, we have demonstrated the rst single-pass optical parametric generation (OPG) and ampli cation (OPA) in MgO:PPLN with record high conversion e ciency of >59% without the requirement of any seed-laser. We have demonstrated a record-low pump threshold energy of 7.5 nJ which is remarkably small and opens a whole new area of research on single-pass frequency conversion devices based on OPG/OPA. Our system is highly tunable near~2 µm region with >8 W of single-pass output power while pumped with~14 W of pump power at 1064 nm. Finally, in this thesis, we have demonstrated the rst phase-locked picosecond OPO with record high output power and spectral bandwidth near~2 µm wavelength region. Such a device can be used as a high spectral brightness phase-locked super-continuum source for a huge array of applications

Author: LLINAS SALA, DANIEL
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: 28/10/2020
Reading date: 03/12/2020
Reading time: 16:00
Reading place: ETSEIB: Videoconferència per COVID-19: https://meet.google.com/hkw-vnge-osy
Thesis director: COLL BERTRAN, JOSEP | ABAD PUENTE, JESUS
Committee:
     PRESIDENT: RUBIO ROMERO, JUAN CARLOS
     SECRETARI: SALLAN LEYES, JOSE MARIA
     VOCAL: VAILLANT, YANCY
Thesis abstract: Experts agree that cyber-physical production systems (CPPS), commonly known as lndustry 4.0 (14.0), have the potential to transform the business landscape through significant improvements in productivity. Those improvements come not only from process efficiency but, specially, from new business models. lmportant for this transformation potential is the fact that those improvements will be on top of the existing, significant, productivity differences between companies, which can make the gap between the leaders and followers potentially unbridgeable.This thesis shows that, in order to successfully cope with this digital disruption, medium-sized firms have to undertake, as a priority, the consolidation of high-performance people management practices. lt also brings evidence that, in the context of CPPS, time is a competitive variable more relevant than ever. Due to the special importance of accumulated learning in digitalization, there are not only very important advantages of being first but, companies that may consider 14.0 as a choice and not an imperative and, in consequence, may postpone its development, risk being left behind.Likewise, and to emphasize this sense of urgency, this thesis shows that the complexity associated with the implementation of 14.0 is high and that the process of doing so can properly be described as a "cultural transformation". Consequently, being a cultural transformation, a fact that inevitably requires time, and knowing that the process of consolidation of high-performance practices also requires time, it becomes an ever more important competitive variable. The urgency for medium-sized companies to start this journey cannot be over emphasized.From the perspective of the level of consolidation of those practices, Spanish medium-sized companies have, in general, a significant deficit, when compared to those of a good part of the OECD countries, usually their most direct competitors. In addition, they also have lower levels of digitization, making the challenge even bigger. This does not mean that there are not medium-sized companies with those high-performance practices consolidated or high levels of digitization but, in general, the average is low and dispersion high.The most relevant challenge of 14.0 does not come from the technological elements intrinsic to this digital disruption, but from the need to innovate in business processes. lt is not intended here to state that technology does not play an important role in lndustry 4.0, it does, but that technological complexity should not hide the fact that it is only a tool, a means toan end. This thesis is structured as follows:a) First, it is shown that there is an agreement in the fact that the expected impact of CPPS on productivity is not only very important, but transformative, disruptive.b) Second, by digging into what happened in other technological innovations that have had a transformative impact in the past, such as the alternate current motor and the information and communication technologies, it is shown that in both cases, there is agreement that their impact on productivity has materialized through innovation in processes and business models.c) Third, evidence is presented that for CPPS, the impact may be even bigger, because digitization seems to create a growing gap over time between winners and followers, generating a kind of virtuous cycle.d) Fourth, it is shown that there is consensus behind the cause of the wide dispersion of productivity and innovation levels: the dispersion in the level of implementation of high-performance people management practices.e) Fifth, evidence is presented that Spanish medium-sized firms are lagging behind in the level of implementation of high-performance people management practices as well as in digitization, when compared with those of the OECD countries. f) Finally, the proposals to be validated, the selected methodology, the results and conclusions are presented.