Universitat Politècnica de Catalunya
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The main subject of this PhD thesis is the study of (1,=l)-identifying codes in digraphs. The results presented in this work are divided into three parts. The first one focusses on the structural properties of digraphs ...
Durant els darrers quaranta anys la geometria diferencial ha estat una eina fonamental per entendre la teoria de control òptim. Habitualment la millor estratègia per resoldre un problema és transformar-lo en un altre ...
This work is based on the family of groups Z^m x F_n, namely free-abelian times free groups, direct products of finitely many copies of Z and a finitely generated free group F_n. These are a special type of right-angled ...
We develop a method to compute a basis of the associated order in a Hopf Galois structure H of the ring of integers O_L of an extension of number or p-adic fields L/K. We state and prove a necessary and sufficient condition ...
(English) The BMS group appears as an infinite-dimensional group of isometries of asymptotically flat spacetimes first introduced by Bondi, Metzner, van der Burg, and Sachs in 1962. This group has gained interest recently ...
En aquesta tesi, presentem una solució per a dos problemes rellevants en la teoria de control: el problema del cost quadràtic garantit i el problema del control H∞, per a un cert tipus de sistemes. Considerem els ...
This thesis develops a large eddy simulation framework for engineering applications using the finite element method. It focuses on the numerical formulation, the wall modelling approach as well as the generation of turbulent ...
(English) The research we have carried out lies within the domain of diffusion problems for elliptic operators that are defined on discrete structures called networks, that are graphs that are capable of discriminating ...
The main objective of this dissertation is the study of the ejection-collision (EC) orbits in the circular and planar Restricted Three Body Problem (RTBP from now on). In particular, we will focus on the analytical and ...
Normalment les grans xarxes d'interconnexió o de comunicacions estan dissenyades utilitzant tècniques de la teoria de grafs. Aquest treball presenta algunes contribucions a aquest tema. Concretament, presentem dues noves ...
In Chapters 1 and 2 of this thesis, we prove that for any non-trivial perturbation depending on any two independent harmonics of a pendulum and a rotor there is global instability. The proof is based on the geometrical ...
Given an elliptic curve E over the complex numbers (CC) given by y^2 = x^3 + ax + b, there exists a lattice L in CC such that the group E(CC) of complex points on E is isomorphic to the complex analytic group CC/L. This ...
(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 ...
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 ...
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 ...
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, ...
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 ...
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 ...
In this work we present the study we did in Graph Theory. In the firsts chapteres of the tesis we study the pieces of information that can be obtained from a graph: the spectrum of the adjacency matrix, the preintersection ...
(English) In this thesis, we study Poisson Structures on Moduli Spaces and Group actions. In particular, we focus on b^m-symplectic structures that can be seen both as symplectic structures with singularities and a particular ...
