Now showing items 1-20 of 27

    La ingeniería y el descarte artefactual de la desalación solar de agua : las industrias de Las Salinas, Sierra Gorda y Oficina Domeyko (1872-1907) 

    Arellano-Escudero, Nelson (Date of defense: 2015-05-26)

    In the nineteenth century, at the Atacama Desert, a phenomenon of competition occurred between different industrial water desalination techniques, one of which had excellent results and a long life using solar energy. It ...

    Singular phenomena in the length spectrum of analytic convex curves 

    Tamarit Sariol, Anna (Date of defense: 2015-07-06)

    Consider the billiard map defined inside an analytic closed strictly convex curve Q. Given q>2 and 0<p<q relatively prime integers, there exist at least two (p,q)-periodic trajectories inside Q. The main goal of this thesis ...

    A contribution to the theory of convolutional codes from systems theory piont of view 

    Um, Laurence Emilie (Date of defense: 2015-05-25)

    Information is such a valuable good of our time. Given that the transmission of information has always been subject to precision problems, knowing the obstacles existing between the transmitter and the receiver, eventual ...

    Propagació d'informació en grafs i digrafs que modelen xarxes d'interconnexió simètriques 

    Mitjana, Margarida (Date of defense: 1999-03-11)

    L'objectiu d'aquesta tesi és aprofondir en l'estudi d'una certa família de dígrafs, els dígrafs de prefix-cicle, donant nous detalls sobre la seva estructura, noves maneres d'enfocar el seu estudi, i dissenyant bons esquemes ...

    Study of invariant manifolds in two different problems : the Hopf-zero singularity and neural synchrony 

    Castejón i Compnay, Oriol (Date of defense: 2015-07-16)

    The main object of study of this thesis are invariant manifolds in the field of dynamical systems. We deal with two different and independent topics, namely, the study of exponentially small splitting of invariant manifolds ...

    Subespacios hiperinvariantes y característicos : una aproximación geométrica 

    Montoro López, Ma. Eulàlia (Date of defense: 2015-05-12)

    The aim of this thesis is to study the hyperinvariant and characteristic subspaces of a matrix, or equivalently, of an endomorphism of a finite dimensional vector space. We restrict ourselves to the case of matrices A with ...

    Application of dynamical system methods to galactic dynamics : from warps to double bars 

    Sánchez Martín, Patricia (Date of defense: 2015-06-29)

    Most galaxies have a warped shape when they are seen from an edge-on point of view. In this work we apply dynamical system methods to find an explanation of this phenomenon that agrees with its abundance among galaxies, ...

    Diffusion through non-transverse heteroclinic chains : a long-time instability for the NLS 

    Simon López, Adrià (Date of defense: 2015-07-06)

    En l'article [CKSTT] els autors proven una inestabilitat global per a l'equació de Schrödinger cúbica desenfocant en el tor 2-dimensional. Per aconseguir-ho, detecten un sistema finit d'equacions diferencials ordinàries, ...

    Dynamics and control of tethered satellite formations in low-Earth orbits 

    Fedi Casas, Manrico (Date of defense: 2015-04-24)

    This thesis is focused on the study of dynamics and control of a multi-tethered satellite formation, where a multi-tethered formation is made up with several satellites (agents) connected by means of cables (tethers). The ...

    Evolutionary dynamics of populations with genotype-phenotype map 

    Ibáñez Marcelo, Esther (Date of defense: 2014-12-19)

    In this thesis we develop a multi-scale model of the evolutionary dynamics of a population of cells, which accounts for the mapping between genotype and phenotype as determined by a model of the gene regulatory network. ...

    Beyond the classical Stefan problem 

    Font Martínez, Francesc (Date of defense: 2014-07-18)

    In this thesis we develop and analyse mathematical models describing phase change phenomena linked with novel technological applications. The models are based on modifications to standard phase change theory. The mathematical ...

    Elliptic and parabolic PDEs : regularity for nonlocal diffusion equations and two isoperimetric problems 

    Serra Montolí, Joaquim (Date of defense: 2014-06-17)

    The thesis is divided into two parts. The first part is mainly concerned with regularity issues for integro-differential (or nonlocal) elliptic and parabolic equations. In the same way that densities of particles with ...

    Integro-differential equations : regularity theory and Pohozaev identities 

    Ros, Xavier (Date of defense: 2014-06-19)

    The main topic of the thesis is the study of Elliptic PDEs. It is divided into three parts: (I) integro-differential equations, (II) stable solutions to reaction-diffusion problems, and (III) weighted isoperimetric and ...

    Global instability in the elliptic restricted three body problem 

    Rosa Ibarra, Abraham de la (Date of defense: 2014-06-16)

    The goal of this thesis is to show global instability or Arnold's diffusion in the elliptic restricted three body problem (ERTBP) by proving the existence of pseudo-trajectories diffusing along the phase space for certain ...

    Propagation in reaction-diffusion equations with fractional diffusion 

    Coulon, Anne-Charline (Date of defense: 2014-07-07)

    This thesis focuses on the long time behaviour of solutions to Fisher-KPP reaction-diffusion equations involving fractional diffusion. This type of equation arises, for example, in spatial propagation or spreading of ...

    Local and global phenomena in piecewise-defined systems: from big bang bifurcations to splitting of heteroclinic manifolds 

    Granados Corsellas, Albert (Date of defense: 2012-09-17)

    In the first part, we formally study the phenomenon of the so-called big bang bifurcations, both for one and two-dimensional piecewise-smooth maps with a single switching boundary. These are a special type of organizing ...

    Haar Wavelets-Based Methods for Credit Risk Portfolio Modeling 

    Ortiz Gracia, Luis (Date of defense: 2011-11-24)

    In this dissertation we have investigated the credit risk measurement of a credit portfolio by means of the wavelets theory. Banks became subject to regulatory capital requirements under Basel Accords and also to the ...

    The equations of Rees algebras of ideals of almost-linear type 

    Muiños Bellester, Ferran (Date of defense: 2011-10-03)

    L’àlgebra de Rees R(I) d’un ideal I d’un anell Noetherià local R juga un paper molt important en àlgebra commutativa i geometria algebraica, perquè Proj(R(I)) és l’explosió (blowup) de l’esquema afí Spec(R) al llarg del ...

    On geometric quantisation of integrable systems with singularities 

    Barbieri Solha, Romero (Date of defense: 2013-10-21)

    This thesis shows an approach to geometric quantisation of integrable systems. It extends some results by Guillemin, Kostant, Rawnsley, Sniatycki and Sternberg in geometric quantisation, considering regular fibrations as ...

    Hodge numbers of irregular varieties and fibrations 

    González Alonso, Víctor (Date of defense: 2013-07-08)

    In this thesis we study the geography of irregular complex projective (or compact Kähler) varieties, paying special attention to the existence of fibrations. The thesis is divided into two parts. In the first one we ...