Departament de Matemàtiques
http://hdl.handle.net/2117/3917
Fri, 24 Feb 2017 07:41:48 GMT2017-02-24T07:41:48ZRedes estrella con la M-propiedad
http://hdl.handle.net/2117/101462
Redes estrella con la M-propiedad
Encinas Bachiller, Andrés Marcos
En este trabajo hacemos una aportación al problema inverso de M –matrices irreducibles, simétricas y singulares, que consiste en determinar c uándo su inversa de grupo es también una M –matriz. Mostramos primero que las matrices involucradas son las asociadas a operadores de Schr ¨odinger sobre redes cuyo pot encial está determinado por un peso sobre el conjunto de vértices. Particularizamos el a nálisis al caso de redes cuyo grafo subyacente es una estrella y mostramos que existen infi nitos operadores de Schr ¨odinger sobre ellas que satisfacen la propiedad descrita
Thu, 23 Feb 2017 12:36:13 GMThttp://hdl.handle.net/2117/1014622017-02-23T12:36:13ZEncinas Bachiller, Andrés MarcosEn este trabajo hacemos una aportación al problema inverso de M –matrices irreducibles, simétricas y singulares, que consiste en determinar c uándo su inversa de grupo es también una M –matriz. Mostramos primero que las matrices involucradas son las asociadas a operadores de Schr ¨odinger sobre redes cuyo pot encial está determinado por un peso sobre el conjunto de vértices. Particularizamos el a nálisis al caso de redes cuyo grafo subyacente es una estrella y mostramos que existen infi nitos operadores de Schr ¨odinger sobre ellas que satisfacen la propiedad descritaMultiplier ideals in two-dimensional local rings with rational singularities
http://hdl.handle.net/2117/101436
Multiplier ideals in two-dimensional local rings with rational singularities
Alberich Carramiñana, Maria; Álvarez Montaner, Josep; Dachs Cadefau, Ferran
The aim of this paper is to study jumping numbers and multiplier ideals of any ideal in a two-dimensional local ring with a rational singularity. In particular we reveal which information encoded in a multiplier ideal determines the next jumping number. This leads to an algorithm to compute sequentially the jumping numbers and the whole chain of multiplier ideals in any desired range. As a consequence of our method we develop the notion of jumping divisor that allows to describe the jump between two consecutive multiplier ideals. In particular we find a unique minimal jumping divisor that is studied extensively.
Thu, 23 Feb 2017 09:19:50 GMThttp://hdl.handle.net/2117/1014362017-02-23T09:19:50ZAlberich Carramiñana, MariaÁlvarez Montaner, JosepDachs Cadefau, FerranThe aim of this paper is to study jumping numbers and multiplier ideals of any ideal in a two-dimensional local ring with a rational singularity. In particular we reveal which information encoded in a multiplier ideal determines the next jumping number. This leads to an algorithm to compute sequentially the jumping numbers and the whole chain of multiplier ideals in any desired range. As a consequence of our method we develop the notion of jumping divisor that allows to describe the jump between two consecutive multiplier ideals. In particular we find a unique minimal jumping divisor that is studied extensively.Dynamics in the centre manifold around equilibrium points in periodically perturbed three-body problems
http://hdl.handle.net/2117/101316
Dynamics in the centre manifold around equilibrium points in periodically perturbed three-body problems
Le Bihan, Bastien; Masdemont Soler, Josep; Gomez Muntané, Gerard; Lizy-Destrez, Stephanie
A new application of the parameterization method is pre- sented to compute invariant manifolds about the equilib- rium points of Periodically Perturbed Three-Body Problems ( PPTBP ). These techniques are applied to obtain high-order semi-numerical approximations of the center manifolds abo ut the points L 1 , 2 of the Sun-perturbed Earth-Moon Quasi- Bicicular Problem ( QBCP ), which is a particular case of PPTBP . The quality of these approximations is compared with results obtained using equivalents of previous normal form procedures. Then, the parameterization is used to ini- tialize the computation of Poincaré maps, which allow to get a qualitative description of the periodically-perturb ed dynamics near the equilibrium points
Tue, 21 Feb 2017 12:51:32 GMThttp://hdl.handle.net/2117/1013162017-02-21T12:51:32ZLe Bihan, BastienMasdemont Soler, JosepGomez Muntané, GerardLizy-Destrez, StephanieA new application of the parameterization method is pre- sented to compute invariant manifolds about the equilib- rium points of Periodically Perturbed Three-Body Problems ( PPTBP ). These techniques are applied to obtain high-order semi-numerical approximations of the center manifolds abo ut the points L 1 , 2 of the Sun-perturbed Earth-Moon Quasi- Bicicular Problem ( QBCP ), which is a particular case of PPTBP . The quality of these approximations is compared with results obtained using equivalents of previous normal form procedures. Then, the parameterization is used to ini- tialize the computation of Poincaré maps, which allow to get a qualitative description of the periodically-perturb ed dynamics near the equilibrium pointsA continuous-time delay chaotic system obtained from a chaotic logistic map
http://hdl.handle.net/2117/101290
A continuous-time delay chaotic system obtained from a chaotic logistic map
Acho Zuppa, Leonardo
This paper presents a procedure to transform a chaotic logistic map into a continuous-time delay chaotic system by using sampled-data representation of continuous-time models. Because of this, the chaotic behavior of the resultant scheme is easy to proofread. A numerical illustration is also realized by utilizing Matlab/Simulink, where the new resultant chaotic attractor is shown
Tue, 21 Feb 2017 10:56:40 GMThttp://hdl.handle.net/2117/1012902017-02-21T10:56:40ZAcho Zuppa, LeonardoThis paper presents a procedure to transform a chaotic logistic map into a continuous-time delay chaotic system by using sampled-data representation of continuous-time models. Because of this, the chaotic behavior of the resultant scheme is easy to proofread. A numerical illustration is also realized by utilizing Matlab/Simulink, where the new resultant chaotic attractor is shownLa resolución numérica de ecuaciones de Viète y su difusión en el curso matemático de Hérigone
http://hdl.handle.net/2117/101287
La resolución numérica de ecuaciones de Viète y su difusión en el curso matemático de Hérigone
Massa Esteve, Maria Rosa; Linero Bas, Antonio
Tue, 21 Feb 2017 10:36:54 GMThttp://hdl.handle.net/2117/1012872017-02-21T10:36:54ZMassa Esteve, Maria RosaLinero Bas, AntonioLyubeznik numbers of local rings and linear strands of graded ideals
http://hdl.handle.net/2117/101277
Lyubeznik numbers of local rings and linear strands of graded ideals
Álvarez Montaner, Josep
We report recent work on the study of Lyubeznik numbers and their relation to invariants coming from the study of linear strands of free resolutions.
Tue, 21 Feb 2017 09:43:13 GMThttp://hdl.handle.net/2117/1012772017-02-21T09:43:13ZÁlvarez Montaner, JosepWe report recent work on the study of Lyubeznik numbers and their relation to invariants coming from the study of linear strands of free resolutions.Arnold's mechanism of diffusion in the spatial circular restricted three-body problem: A semi-analytical argument
http://hdl.handle.net/2117/101125
Arnold's mechanism of diffusion in the spatial circular restricted three-body problem: A semi-analytical argument
Delshams Valdés, Amadeu; Gidea, Marian; Roldán, Pablo
We consider the spatial circular restricted three-body problem, on the motion of an infinitesimal body under the gravity of Sun and Earth. This can be described by a 3-degree of freedom Hamiltonian system. We fix an energy level close to that of the collinear libration point L1, located between Sun and Earth. Near L1 there exists a normally hyperbolic invariant manifold, diffeomorphic to a 3-sphere. For an orbit confined to this 3-sphere, the amplitude of the motion relative to the ecliptic (the plane of the orbits of Sun and Earth) can vary only slightly.
We show that we can obtain new orbits whose amplitude of motion relative to the ecliptic changes significantly, by following orbits of the flow restricted to the 3-sphere alternatively with homoclinic orbits that turn around the Earth. We provide an abstract theorem for the existence of such ‘diffusing’ orbits, and numerical evidence that the premises of the theorem are satisfied in the three-body problem considered here. We provide an explicit construction of diffusing orbits.
The geometric mechanism underlying this construction is reminiscent of the Arnold diffusion problem for Hamiltonian systems. Our argument, however, does not involve transition chains of tori as in the classical example of Arnold. We exploit mostly the ‘outer dynamics’ along homoclinic orbits, and use very little information on the ‘inner dynamics’ restricted to the 3-sphere.
As a possible application to astrodynamics, diffusing orbits as above can be used to design low cost maneuvers to change the inclination of an orbit of a satellite near L1 from a nearly-planar orbit to a tilted orbit with respect to the ecliptic. We explore different energy levels, and estimate the largest orbital inclination that can be achieved through our construction.
Thu, 16 Feb 2017 09:57:15 GMThttp://hdl.handle.net/2117/1011252017-02-16T09:57:15ZDelshams Valdés, AmadeuGidea, MarianRoldán, PabloWe consider the spatial circular restricted three-body problem, on the motion of an infinitesimal body under the gravity of Sun and Earth. This can be described by a 3-degree of freedom Hamiltonian system. We fix an energy level close to that of the collinear libration point L1, located between Sun and Earth. Near L1 there exists a normally hyperbolic invariant manifold, diffeomorphic to a 3-sphere. For an orbit confined to this 3-sphere, the amplitude of the motion relative to the ecliptic (the plane of the orbits of Sun and Earth) can vary only slightly.
We show that we can obtain new orbits whose amplitude of motion relative to the ecliptic changes significantly, by following orbits of the flow restricted to the 3-sphere alternatively with homoclinic orbits that turn around the Earth. We provide an abstract theorem for the existence of such ‘diffusing’ orbits, and numerical evidence that the premises of the theorem are satisfied in the three-body problem considered here. We provide an explicit construction of diffusing orbits.
The geometric mechanism underlying this construction is reminiscent of the Arnold diffusion problem for Hamiltonian systems. Our argument, however, does not involve transition chains of tori as in the classical example of Arnold. We exploit mostly the ‘outer dynamics’ along homoclinic orbits, and use very little information on the ‘inner dynamics’ restricted to the 3-sphere.
As a possible application to astrodynamics, diffusing orbits as above can be used to design low cost maneuvers to change the inclination of an orbit of a satellite near L1 from a nearly-planar orbit to a tilted orbit with respect to the ecliptic. We explore different energy levels, and estimate the largest orbital inclination that can be achieved through our construction.Diseño y construcción de un prototipo de plataforma Stewart
http://hdl.handle.net/2117/101116
Diseño y construcción de un prototipo de plataforma Stewart
Rossell Garriga, Josep Maria; Blanes Priego, Manel; Vicente Rodrigo, Jesús; Rubió Massegú, Josep; Palacios Quiñonero, Francisco
Wed, 15 Feb 2017 16:31:47 GMThttp://hdl.handle.net/2117/1011162017-02-15T16:31:47ZRossell Garriga, Josep MariaBlanes Priego, ManelVicente Rodrigo, JesúsRubió Massegú, JosepPalacios Quiñonero, Francisco30 anys del Seminari de Teoria de Nombres de Barcelona, STNB 2016
http://hdl.handle.net/2117/101086
30 anys del Seminari de Teoria de Nombres de Barcelona, STNB 2016
Alsina Aubach, Montserrat
Wed, 15 Feb 2017 14:07:17 GMThttp://hdl.handle.net/2117/1010862017-02-15T14:07:17ZAlsina Aubach, MontserratData-driven methodologies for structural damage detection based on machine learning applications
http://hdl.handle.net/2117/101068
Data-driven methodologies for structural damage detection based on machine learning applications
Vitola Oyaga, Jaime; Anaya Vejar, Maribel; Tibaduiza Burgos, Diego Alexander; Pozo Montero, Francesc
Structural health monitoring (SHM) is an important research area, which interest is the damage identification process. Different information about the state of the structure can be obtained in the process, among them, detection, localization and classification of damages are mainly studied in order to avoid unnecessary maintenance procedures in civilian and military structures in several applications. To carry out SHM in practice, two different approaches are used, the first is based on modelling which requires to build a very detailed model of the structure, while the second is by means of data-driven approaches which use information collected from the structure under different structural states and perform an analysis by means of data analysis . For the latter, statistical analysis and pattern recognition have demonstrated its effectiveness in the damage identification process because real information is obtained from the structure through sensors installed permanently to the observed object allowing a real-time monitoring. This chapter describes a damage detection and classification methodology, which makes use of a piezoelectric active system which works in several actuation phases and that is attached to the structure under evaluation, principal component analysis, and machine learning algorithms working as a pattern recognition methodology. In the chapter, the description of the developed approach and the results when it is tested in one aluminum plate are also included.
Wed, 15 Feb 2017 11:26:05 GMThttp://hdl.handle.net/2117/1010682017-02-15T11:26:05ZVitola Oyaga, JaimeAnaya Vejar, MaribelTibaduiza Burgos, Diego AlexanderPozo Montero, FrancescStructural health monitoring (SHM) is an important research area, which interest is the damage identification process. Different information about the state of the structure can be obtained in the process, among them, detection, localization and classification of damages are mainly studied in order to avoid unnecessary maintenance procedures in civilian and military structures in several applications. To carry out SHM in practice, two different approaches are used, the first is based on modelling which requires to build a very detailed model of the structure, while the second is by means of data-driven approaches which use information collected from the structure under different structural states and perform an analysis by means of data analysis . For the latter, statistical analysis and pattern recognition have demonstrated its effectiveness in the damage identification process because real information is obtained from the structure through sensors installed permanently to the observed object allowing a real-time monitoring. This chapter describes a damage detection and classification methodology, which makes use of a piezoelectric active system which works in several actuation phases and that is attached to the structure under evaluation, principal component analysis, and machine learning algorithms working as a pattern recognition methodology. In the chapter, the description of the developed approach and the results when it is tested in one aluminum plate are also included.