Doctoral School

Reading date: 20/09/2024

• HOSTENCH RUIZ, ORIOL: Hans Scharoun y la ciudad orgánica: Otra mirada al fenómeno urbano moderno
  
  Author: HOSTENCH RUIZ, ORIOL
  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 THEORY AND HISTORY OF ARCHITECTURE
  Department: Department of History and Theory of Architecture and Communication Techniques (THATC)
  Mode: Normal
  Deposit date: 12/07/2024
  Reading date: 20/09/2024
  Reading time: 12:30
  Reading place: Presencial (ETSAB. Planta Baixa. Sala de Graus)
  Thesis director: GRAUS ROVIRA, RAMON
  Committee:
       PRESIDENT: GURIDI GARCIA, RAFAEL
       SECRETARI: GARNICA GONZÁLEZ BÁRCENA, JULIO FIDEL
       VOCAL: TARTÁS RUIZ, MARIA CRISTINA ISABEL
  Thesis abstract: German architect Hans Scharoun's (1893-1972) body of work (written, drawn and constructed) pays careful attention to the urban phenomenon of the modern city. One of the aims of this study is to indicate Scharoun's journey to rethink the city in a way which differed from that which was proposed by the neue Sachlichkeit or by the Charter of Athens in order to propose an organic approach which was similar to the approach taken by Hugo Häring, whose work held in high regard.In order to demonstrate Scharoun's continued interest in urban matters, the doctoral thesis will be structured into two parts. The first studies the architect's urban projects in chronological order up until the outbreak of WWII and the second explores postwar Scharoun's key concepts of urban matters.The impact of Camillo Sitte's work on Scharoun is reflected in the Dortmund and Prenzlau competitions which took place in 1919, his entry into expressionist circles is reflected in the glimpses of the Stadtkrone drawn for Gelsenkirchen (1920) and his definitive conversion to the principles of organicism becomes apparent in the competitions for Königsberg (1922) and Bochum (1925). Scharoun's return to Berlin throws him into the creative whirlwind of the great modern metropolis. He participated in the Friedrichstraße competition (1921), the ministerial gardens competition (1927) and the Reichstag extension competition (1927). Likewise, he built his first residential developments with private developers that would lead to his great commission of the interwar period, the Groβsiedlung Siemensstadt (1929-30).The organic and expressionist architecture of the German Neues Bauen in the interwar period lays the foundations for a new concept of city after the Second World War, alongside a need for the German culture to be rebuilt and a physically and mentally drained continent awaiting a social reformulation to redeem it.Hans Scharoun stood out amongst his peers for remaining in Germany during and after the Second World War. Within him the theoretical concepts of medieval city construction and baroque updated by Camillo Sitte, Hugo Häring's theories on organic architecture and new visions of the world of philosophers such as Jean Gebser or Ernst Cassirer come together to be able to propose not only a new architecture, but also a new vision of urban planning based on historical, human and spatial values.This research maintains that this new urban order arises from the concepts of Aperspective space outlined by Jean Gebser, of treating the city like a Satdtlandschaft (urban landscape) being manageable from the medium scale proposed by Scharoun via his design of the Wohnzelle (dwelling cells), first proposed in Friedrichshain and later of the Wohngehöfte (dwelling homesteads) in Charlottenburg-Nord. It also examines the mutative transformation in all possible scales at the moment of design and of the ever-present idea of a Raum der Mitte (central space) to which the whole design refers via the regulating lines.The thesis recovers three texts which have been left out of Scharoun's historiography, but which were published in Medizin und Städtebau (1957): "The urban structure and its transformation throughout history", "Organizational principles and concepts that can lead to urban structure" and "The meaning of spatial structure for the future of the city". Within these the mature Scharoun brings together his concern for a holistic explanation of the urban form, its transformation over time and its geographical scope as a mental framework to redesign the city.Hans Scharoun slowly decanted a theory and certain urban practices denoting the conditions for a new "organic" city, but also paved the way for a deontology of public space in a city that aspired to be more humane.
  

• 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
  Reading date: 20/09/2024
  Reading time: 10:30
  Reading place: Defensa pública a la Sala E101 - Edifici C6 (FIB) - Campus Nord - Barcelona
  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.
  

• SOUNDARAPANDIAN, KARUPPASAMY: Graphene based photodetectors for on-chip and free-space data communication applications
  
  Author: SOUNDARAPANDIAN, KARUPPASAMY
  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: 10/07/2024
  Reading date: 20/09/2024
  Reading time: 09:30
  Reading place: ICFO, Mediterranean Technology Park, Avinguda Carl Friedrich Gauss, 3, 08860 Castelldefels, Barcelona
  Thesis director: KOPPENS, FRANK
  Committee:
       PRESIDENT: BOGGILD, PETER
       SECRETARI: PRUNERI, VALERIO
       VOCAL: COLETTI, CAMILLA
  Thesis abstract: Moore's law, a longstanding guide for the semiconductor industry, successfully predicted the exponential growth in computing power by doubling transistor counts every two years. However, recent challenges in maintaining this pace, attributed to physical limitations, energy consumption, and escalating costs, have prompted a shift in focus towards two-dimensional (2D) materials in semiconductor technology. This thesis aims to bridge the gap in understanding the complexities of incorporating 2D materials, such as Graphene (Gr), Transition Metal Dichalcogenides (TMD), and hexagonal boron nitride (hBN), into Complementary Metal-Oxide-Semiconductor CMOS platforms, paving the way for innovative optoelectronic devices with improved functionality to overcome these challenges. High-quality heterostructuresThis thesis investigates the crucial role of encapsulants and substrates in Gr-based heterostructures, highlighting their impact on electronic transport characteristics, such as hysteresis (∆n), carrier mobility (µ), and residual charge carrier concentration (n*). Owing to the quality and integration complexity of scalable large-area thick hBN, this thesis explores the utilization of TMD-like tungsten diselenide (WSe2) and tungsten disulfide (WS2) as substrates and encapsulants, respectively, for Gr. The hybrid heterostructures fabricated with WSe2/Gr/hBN and WS2/Gr/hBN exhibited a high µ of ~170,000 and ~140,000 cm2V-1s-1 with a n^*of ~7 and 8 x 1010 cm-2 respectively. This study underscores the significance of substrate engineering, particularly for WS2. A successful demonstration of the effectiveness of TFSI-treated WS2 in encapsulating Gr and its role as a gate dielectric has been established. The treated devices exhibited remarkable stability and resilience, leading to a low ∆n of ~2 x 109 cm-2 with a µ of ~62,000 cm2V-1s-1 and a n^* of ~1.7 x 1011 cm-2. Waveguide-integrated photodetectorsThe exponential growth of internet users and data traffic necessitates higher bandwidth capabilities in communication systems. Optical transceivers play a pivotal role in meeting this demand, particularly in data centers and broadband access networks. This thesis focuses on the crucial components of optical transceivers, specifically photodetectors (PD), optimized for a wavelength of 1550 nm, a standard for long-distance communication in optical fibers. This thesis explores a photothermoelectric (PTE) WSe2 encapsulated Gr photodetector on a waveguide to address this challenge. Up on a comprehensive analysis of the device's design, the fabricated PD with different widths exhibited a responsivity up to ~12 V/W (long) or 0.1 A/W and ~32 mA/W or 18 V/W (short) with a setup limited bandwidth of 110 GHz. PDs also demonstrated direct detection of NRZ and PAM-4 optical signals up to 120 and 160 Gbps, respectively.Wireless receiversMeanwhile, in wireless telecommunications, efforts must be directed towards boosting data rates to accommodate growing data traffic, as indicated by Edholm's law. The proposed 6G wireless devices are expected to achieve peak data rates of up to 1Tbps. To overcome speed bottlenecks, this thesis proposes exploring the terahertz (THz) range, with a focus on the sub-THz (~200GHz-300GHz) window, exhibiting low-attenuation demands for short-range (<200m) wireless applications. We performed an extensive investigation and optimization of the performance of a PTE-based Gr photodetector using various encapsulants. Among these, the hBN-encapsulated Gr PDs exhibited superior performance compared to their counterparts (PD with CVD Gr), with an elevated responsivity of ~240 (~30) V/W and low noise equivalent power (NEP) of ~1 (~9) x 10-11 W/√Hz. The fabricated PDs exhibited a bandwidth of approximately 1.9 GHz, enabling data rates of 2 Gbps. Finally, we developed a Gr-based receiver, establishing a sub-terahertz wireless communication link that achieved data rates of up to 3 Gbps and efficiently operated over a distance of 2.5 meters.
  

Reading date: 23/09/2024

• SEDAR, MOHOTTIGE ROSHAN MADHUSANKA: Misbehaviour Detection and Trustworthy Collaboration in Vehicular Communication Networks
  
  Author: SEDAR, MOHOTTIGE ROSHAN MADHUSANKA
  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: 20/06/2024
  Reading date: 23/09/2024
  Reading time: 11:00
  Reading place: Defensa pública a l'Aula C4-021B, EETAC, Castelldefels, Barcelona
  Thesis director: ALONSO ZARATE, JESUS | VAZQUEZ GALLEGO, FRANCISCO
  Committee:
       PRESIDENT: MARQUEZ BARJA, JOHANN MARCELO
       SECRETARI: PEREZ ROMERO, JORGE
       VOCAL: GOZÁLVEZ SEMPERE, JAVIER MANUEL
  Thesis abstract: The integration of advanced wireless technologies, e.g., cellular and IEEE 802.11p, in modern vehicles enables vehicle-to-everything (V2X) communication, fostering the next-generation Internet-of-Vehicles (IoV). The rise of IoV leads to more connected vehicles on roads, capable of making informed and coordinated decisions through real-time information sharing among vehicles, communication infrastructure, pedestrians, or roadside units (RSUs). However, V2X and IoV technologies inadvertently bring unprecedented challenges involving security and privacy vulnerabilities. Security threats and attacks can emerge from both malicious outsiders and insiders in V2X communication. Detecting and containing misbehaviours, particularly those initiated by rogue insiders, present challenging yet critical tasks for ensuring road safety. Furthermore, the pervasive use of artificial intelligence and machine learning (AI/ML) tools across various aspects poses potential threats to secure V2X operations. Motivated by these challenges, this doctoral thesis focuses on enhancing the security, robustness, and trustworthiness of V2X communications by enabling efficient and effective misbehaviour detection and fostering trustworthy collaboration. Specifically, we focus on (i) achieving effective and efficient misbehaviour detection with high accuracy and minimal false alarms, leveraging diverse spatiotemporal characteristics in vehicular data, and (ii) facilitating trustworthy information sharing for collaborative misbehaviour detection, with an emphasis on generalisability and the ability to detect previously unseen and partially observable attacks.The absence of standardised approaches to address misbehaviours calls for advanced AI/ML-based solutions capable of handling the surging volume of data, enhancing robustness and generalisability, and meeting the real-time demands of V2X applications. To this end, we propose a generic deep RL (DRL) misbehaviour detection methodology capable of dynamically improving detection through interactions and experiences by leveraging various spatiotemporal behaviours present in the ambient vehicular measurement space. The scarcity of labelled vehicular data exacerbates the effective training of AI/ML-based models. Motivated by this challenge, we propose an ensemble learning framework for misbehaviour detection, coupled with unsupervised learning and a DRL model. This enables the detection of attacks from unlabelled vehicular data, facilitating the generalisation and detection of new and unseen attack variants. Additionally, addressing adversarial attacks poses a significant challenge, requiring enhanced solutions to make AI/ML-based misbehaviour detection more resilient against such threats. Towards this, we introduce and evaluate a tailored DRL approach designed to protect V2X communication systems against adversarial attacks, as well as mitigate issues stemming from inappropriate formatting of input training data due to vehicular sensor malfunctions or reading errors. By implementing data poisoning adversarial attacks, we demonstrate the resilience of the DRL-based misbehaviour detection approach even under severe conditions of sophisticated adversarial manipulation.Building upon the proposed DRL-based misbehaviour detection approach, we introduce a novel scheme for collaborative misbehaviour detection. This scheme involves deploying a DRL-based misbehaviour detection model in an RSU at the network edge. It leverages transfer learning principles to share the knowledge learned about misbehaviours at the source RSUs with the target RSU, enabling the reuse of relevant expertise for collaborative misbehaviour detection. Considering data poisoning attacks aimed at influencing misbehavior detection, we implement selective knowledge transfer from trustworthy RSUs to avoid adversarial interference. We introduce a semantic relatedness metric to quantify each RSU's trust level for collaborative misbehavior detection.
  

Reading date: 24/09/2024

• 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
  Reading date: pending
  Reading time: pending
  Reading place: pending
  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.