Now showing items 65-84 of 116

    Lattice-based zero-knowledge proofs of knowledge 

    Martínez Pinilla, Ramiro (Date of defense: 2023-09-29)

    (English) The main goal of this dissertation is to develop new lattice-based cryptographic schemes. Most of the cryptographic protocols that each and every one of us use on a daily basis are only secure under the assumption ...

    Local preconditioning for parallel iterative solvers 

    Córdoba Pañella, Paula (Date of defense: 2022-04-22)

    This thesis aims at improving the convergence of iterative solvers, used for algebraic systems coming from the discretization of partial differential equations (PDE), in the context of large scale simulations and high ...

    Locally adaptive phase-field models and transition to fracture 

    Muixí Ballonga, Alba (Date of defense: 2020-11-30)

    This thesis proposes a new computational model for the efficient simulation of crack propagation, through the combination of a phase-field model in small subdomains around crack tips and a discontinuous model in the rest ...

    Long-term privacy in electronic voting systems 

    Costa Miranda, Núria (Date of defense: 2021-04-14)

    This PhD thesis focuses on lattice-based cryptography and how to apply it to build post-quantum online voting systems. It is the result of the research done by the author at Scytl in close collaboration with Dr. Paz Morillo, ...

    Mathematical and computational modeling of active cellular flows 

    Font i Reverter, Jordi (Date of defense: 2023-06-08)

    (English) During development, cellular tissues undergo dramatic reconfigurations as a result of organized flows driven by active forces. Depending on the system, cellular flows and active forces can be understood from a ...

    Mathematical and computational modeling of flexoelectricity at fixed and moving interfaces, fracture surfaces and contact 

    Barceló Mercader, Jordi (Date of defense: 2023-09-08)

    (English) Flexoelectricity is a two-way coupling between strain gradient and polarisation or strain and polarization-gradient. Harnessing flexoelectricity as a functional property requires gradient engineering. This is a ...

    Mathematical modelling of diffusion processes at the nanoscale 

    Ribera Ponsa, Helena (Date of defense: 2018-03-16)

    In this thesis we study diffusion processes of nanoparticle evolution and develop appropriate models with the aim of being able to optimise their functions according to the needs of industry. Two distinct diffusion processes ...

    Mechanics of epithelial tissue subjected to controlled pressure 

    Chahare, Nimesh Ramesh (Date of defense: 2023-06-20)

    (English) Epithelial sheets form specialized 3D structures suited to their physiological roles, such as branched alveoli in the lungs, tubes in the kidney, and villi in the intestine. To generate and maintain these structures, ...

    Metric-aware optimization of high-order meshes for curved adaptivity 

    Aparicio Estrems, Guillermo (Date of defense: 2023-04-26)

    (English) To enhance the simulation accuracy when the solution presents sharp curved features, the community of high-order methods has started to curve not only the boundary but also the interior of unstructured high-order ...

    Modeling and numeriacal study of nonsmooth dynamical systems. Applications to Mechanical and Power Electronics Systems. 

    Merillas Santos, Iván (Date of defense: 2007-02-22)

    This thesis is concerned with the modeling and numerical study of nonsmooth dynamical systems (NSDS). The first part of the thesis deals with the modeling of some DC-DC power converters using the complementarity formalism. ...

    Modelització de corbes i superfícies amb aplicacions al disseny geomètric assistit per ordinador i a l'arquitectura 

    Monreal, Amadeo (Date of defense: 2001-12-17)

    En primer lloc, s'evidencia que el disseny que involucra grafisme es pot analitzar com articulat en dos nivells o etapes, un de concepció, intel·lectual, i un altre d'execució, manual o físic, ambdós sempre en interrelació ...

    Monotonicity preserving shock capturing techniques for finite elements 

    Hierro Fabregat, Alba (Date of defense: 2016-11-28)

    The main object of study of this thesis is the development of artificial diffusion shock capturing techniques for continuous and discontinuous Galerkin (cG and dG) approximations of the convection-diffusion problem. Special ...

    Multimodal ventricular tachycardia analysis : towards the accurate parametrization of predictive HPC electrophysiological computational models 

    López-Yunta, Mariña (Date of defense: 2018-07-30)

    After a myocardial infarction, the affected areas of the cardiac tissue suffer changes in their electrical and mechanical properties. This post-infarction scar tissue has been related with a particular type of arrhythmia: ...

    Multiscale clutch models for cell mechanics 

    Venturini, Chiara (Date of defense: 2022-07-22)

    Integrin-based cell adhesion is a key mechanism in fundamental biological processes such as cell migration and wound healing, and in diseases like osteoporosis and cancer. For example, during migration, cells form adhesion ...

    A multisymplectic approach to gravitational theories 

    Gaset Rifà, Jordi (Date of defense: 2018-07-25)

    The theories of gravity are one of the most important topics in theoretical physics and mathematical physics nowadays. The classical formulation of gravity uses the Hilbert-Einstein Lagrangian, which is a singular ...

    New geometrical and dynamical techniques for problems in celestial mechanics 

    Braddell, Róisín (Date of defense: 2021-02-17)

    In this thesis, we study the application of symplectic geometry, regular and singular, to symplectic dynamical systems.We start with a motivating case: the relation between symplectic foliations and global transverse ...

    Nodal distributions on the high-dimensional simplex for high-order interpolation and integration 

    Jiménez Ramos, Albert (Date of defense: 2023-06-28)

    (English) To simulate unsteady phenomena on complex moving geometry, computational scientists and engineers have been interested in unstructured space-time discretizations. These space-time discretizations aim to overcome ...

    Non-classical thermal transport and phase change at the nanoscale 

    Calvo Schwarzwälder, Marc (Date of defense: 2019-07-12)

    For 200 years, Fourier’s law has been used to describe heat transfer with excellent results. However, as technology advances, more and more situations arise where heat conduction is not well described by the classical ...

    Normal forms around lower dimensional tori of hamiltonian systems 

    Villanueva Castelltort, Jordi (Date of defense: 1997-03-10)

    L'objectiu bàsic d'aquesta tesi és l'estudi de la dinàmica a l'entorn de tors de dimensió baixa de sistemes hamiltonians analítics. Per aquest estudi l'eina fonamental és l'ús de formes normals al voltant d'aquests ...

    Novel consensus strategies applied to spacecraft formation flight 

    Paita, Fabrizio (Date of defense: 2017-09-04)

    In this thesis we consider the problem of developing distributed control strategies for spacecraft formation flying. In light of possible interferometric applications, the study is conducted in two different contexts: ...