DSpace Collection:
http://hdl.handle.net/2117/3918
2015-03-29T22:33:37ZJ2 effect and elliptic inclined periodic orbits in the collision three-body problem
http://hdl.handle.net/2117/21117
Title: J2 effect and elliptic inclined periodic orbits in the collision three-body problem
Authors: Barrabes, Esther; Cors Iglesias, Josep Maria; Pinyol, Conxita; Soler Villanueva, Jaume
Abstract: The existence of a new class of inclined periodic orbits of the collision restricted
three{body problem is shown. The symmetric periodic solutions found are perturbations of elliptic
kepler orbits and they exist only for special values of the inclination and are related to the motion
of a satellite around an oblate planet.Nonlinear equations for fractional Laplacians, I: Regularity, maximum principles, and Hamiltonian estimates
http://hdl.handle.net/2117/22391
Title: Nonlinear equations for fractional Laplacians, I: Regularity, maximum principles, and Hamiltonian estimates
Authors: Cabré Vilagut, Xavier; Sire, Yannick
Abstract: This is the first of two articles dealing with the equation (-)sv = f (v) in Rn, with s ¿ (0,1), where (-)s stands for the fractional Laplacian — the in¿nitesimal generator of a Lévy process. This equation can be realized as a local linear degenerate elliptic equation in Rn+1+ together with a nonlinear Neumann boundary condition on ¿Rn+1 + =Rn.
In this ¿rst article, we establish necessary conditions on the nonlinearity f to admit certain type of solutions, with special interest in bounded increasing solutions in all of R. These necessary conditions (which will be proven in a follow-up paper to be also suficient for the existence of a bounded increasing solution) are derived from an equality and an estimate involving a Hamiltonian — in the spirit of a result of Modica for the Laplacian. Our proofs are uniform ass ¿1, establishing in the limit the corresponding known results for the Laplacian.
In addition, we study regularity issues, as well as maximum and Harnack principles associated to the equation.Beilinson-Flach elements and Euler systems I: syntomic regulators and p-adic Rankin L-series
http://hdl.handle.net/2117/27057
Title: Beilinson-Flach elements and Euler systems I: syntomic regulators and p-adic Rankin L-series
Authors: Bertolini, Massimo; Darmon, Henri; Rotger Cerdà, Víctor
Abstract: This article is the first in a series devoted to the Euler system arising from p-adic families of Beilinson-Flach elements in the first K-group of the product of two modular curves. It relates the image of these elements under the p-adic syntomic regulator (as described by Besser (2012)) to the special values at the near-central point of Hida's p-adic Rankin L-function attached to two Hida families of cusp forms.2015-03-26T12:08:25ZAn algorithm to compute the primitive elements of an embedding dimension three numerical semigroups
http://hdl.handle.net/2117/27055
Title: An algorithm to compute the primitive elements of an embedding dimension three numerical semigroups
Authors: Aguiló Gost, Francisco de Asis L.; García Sánchez, Pedro A.; Llena, David
Abstract: We give an algorithm to compute the set of primitive elements for an embedding dimension three numerical semigroups. We show how we use this procedure in the study of the construction of L-shapes and the tame degree of the semigroup.2015-03-26T11:56:18ZDenumerants of 3-numerical semigroups
http://hdl.handle.net/2117/27054
Title: Denumerants of 3-numerical semigroups
Authors: Aguiló Gost, Francisco de Asis L.; García Sánchez, Pedro A.; Llena, David
Abstract: Denumerants of numerical semigroups are known to be difficult to obtain, even with small embedding dimension of the semigroups. In this work we give some results on denumerants of 3-semigroups S=<a,b,c>S=<a,b,c>. Closed expressions are obtained under certain conditions.2015-03-26T11:48:29ZCompatible spanning trees
http://hdl.handle.net/2117/26968
Title: Compatible spanning trees
Authors: Garcia Olaverri, Alfredo Martin; Huemer, Clemens; Hurtado Díaz, Fernando Alfredo; Tejel Altarriba, Francisco Javier
Abstract: Two plane geometric graphs are said to be compatible when their union is a plane geometric graph. Let S be a set of n points in the Euclidean plane in general position and let T be any given plane geometric spanning tree of S. In this work, we study the problem of finding a second plane geometric tree T' spanning S, such that is compatible with T and shares the minimum number of edges with T. We prove that there is always a compatible plane geometric tree T' having at most #n - 3#/4 edges in common with T, and that for some plane geometric trees T, any plane tree T' spanning S, compatible with T, has at least #n - 2#/5 edges in common with T. #C# 2013 Elsevier B.V. All rights reserved.2015-03-24T10:58:00ZLower bounds of end effects for a nonhomogeneous isotropic linear elastic solid in anti-plane shear
http://hdl.handle.net/2117/26875
Title: Lower bounds of end effects for a nonhomogeneous isotropic linear elastic solid in anti-plane shear
Authors: Leseduarte Milán, María Carme; Quintanilla de Latorre, Ramón
Abstract: In this paper we give lower bounds for the spatial decay of the solutions for anti-plane shear deformations in the case of
isotropic inhomogeneous elastic materials. We first consider the case when the shear modulus only depends on the lateral
direction. By means of the logarithmic convexity arguments we obtain the required estimates. Some pictures illustrate
our results. We also study the general inhomogeneity. We give some lower bounds whenever shear modulus
satisfies several requirements.2015-03-19T18:59:40ZSpatial stability in linear thermoelasticity
http://hdl.handle.net/2117/26874
Title: Spatial stability in linear thermoelasticity
Authors: Knops, Robin J.; Quintanilla de Latorre, Ramón
Abstract: Uniqueness and spatial stability are investigated for smooth solutions to boundary value
problems in non-classical linearised and linear thermoelasticity subject to certain conditions
on material coefficients. Uniqueness is derived for standard boundary conditions
on bounded regions using a generalisation of Kirchhoff’s method. Spatial stability is discussed
for the semi-infinite prismatic cylinder in the absence of specified axial asymptotic
behaviour. Alternative growth and decay estimates are established principally for the
cross-sectional energy flux that is shown to satisfy a first order differential inequality.
Uniqueness in the class of solutions with bounded energy follows as a corollary.
Separate discussion is required for the linearised and linear theories. Although the general
approach is similar for both theories, the argument must be considerably modified for
the treatment of the linear theory.2015-03-19T18:33:43ZPassivity-based control of a wound-rotor synchronous motor
http://hdl.handle.net/2117/26849
Title: Passivity-based control of a wound-rotor synchronous motor
Authors: Dòria Cerezo, Arnau; Batlle Arnau, Carles; Espinosa Pérez, Gerardo
Abstract: This study presents a new non-linear passivity-based controller for a wound-rotor synchronous machine, acting as a motor drive. The control objectives are stated in the dq-frame, and the port-controlled Hamiltonian model is also obtained. A power flow analysis allows to state the control goals in terms of ohmic losses reduction, and motivates the use of the field current for the reactive power compensation. From the Hamiltonian structure, the simultaneous interconnection and damping assignment technique is used to compute the control action, which results in a controller with a simpler architecture than the standard one for this class of machines, able to cope with both positive and negative external mechanical loads and having thus bidirectional power capabilities. The robustness of the control action is also taken into account in the design procedure. Finally, the computed controller is validated via numerical simulations.2015-03-19T13:22:05ZStatistical characterization of strong and mid solar flares and sun EUV rate monitoring with GNSS
http://hdl.handle.net/2117/26834
Title: Statistical characterization of strong and mid solar flares and sun EUV rate monitoring with GNSS
Authors: Monte Moreno, Enrique; Hernández Pajares, Manuel; García Rigo, Alberto; Beniguel, Yannick; Orús Pérez, Raul; Prieto Cerdeira, Roberto; Schlueter, Stefan
Abstract: The global network of permanent Global Navigation Satellite Systems (GNSS) receivers has become an useful and
affordable way of monitoring the Solar EUV flux rate, especially -for the time being- in the context of Major and
Mid geoeffective intensity Solar Flares (M. Hernandez-Pajares et al., SpaceWeather, doi:10.1029/2012SW000826,
2012). In fact the maturity of this technique (GNSS Solar FLAre Indicator, GSFLAI) has allowed to incorporate
it in operational real-time (RT) conditions, thanks to the availability of global GNSS datastreams from the RT
International GNSS Network (M. Caissy et al, GPS World, June 1, 2012), and performed in the context of the
MONITOR and MONITOR2 ESA-funded projects (Y. Beniguel et al., NAVITEC Proc., 978-1-4673-2011-5
IEEE, 2012).
The main goal of this presentation is to summarize a detailed recent study of the statistical properties of
Solar Flares (E. Monte and M. Hernandez-Pajares, J. Geophys. Res., doi:10.1002/2014JA020206, 2014) by
considering the GNSS proxy of EUV rate (GSFLAI parameter) computed independently each 30 seconds during
the whole last solar cycle. An statistical model has been characterized that explains the empirical results such
as (a) the persistence and presence of bursts of solar flares and (b) their long tail peak values of the solar flux
variation, which can be characterized by: (1) A fractional Brownian model for the long-term dependence, and (2),
a power law distribution for the time series extreme values.
Finally, an update of the Solar Flares’ occurrence during the recent months of Solar Activity, gathered in
RT within MONITOR2 project, will close the paper.2015-03-19T11:39:57ZRational periodic sequences for the Lyness recurrence
http://hdl.handle.net/2117/26772
Title: Rational periodic sequences for the Lyness recurrence
Authors: Gasull, Armengol; Mañosa Fernández, Víctor; Xarles Ribas, Xavier2015-03-17T16:27:07ZQuantum Google algorithm
http://hdl.handle.net/2117/26756
Title: Quantum Google algorithm
Authors: Paparo, Giuseppe Davide; Muller, Markus; Comellas Padró, Francesc de Paula; Martin Delgado, Miguel Angel
Abstract: We review the main findings on the ranking capabilities of the recently proposed Quantum PageRank algorithm (G.D. Paparo et al., Sci. Rep. 2, 444 (2012) and G.D. Paparo et al., Sci. Rep. 3, 2773 (2013)) applied to large complex networks. The algorithm has been shown to identify unambiguously the underlying topology of the network and to be capable of clearly highlighting the structure of secondary hubs of networks. Furthermore, it can resolve the degeneracy in importance of the low-lying part of the list of rankings. Examples of applications include real-world instances from the WWW, which typically display a scale-free network structure and models of hierarchical networks. The quantum algorithm has been shown to display an increased stability with respect to a variation of the damping parameter, present in the Google algorithm, and a more clearly pronounced power-law behaviour in the distribution of importance among the nodes, as compared to the classical algorithm.2015-03-17T12:11:10ZThe number of spanning trees in Apollonian networks
http://hdl.handle.net/2117/26688
Title: The number of spanning trees in Apollonian networks
Authors: Zhang, Zhongzhi; Wu, Bin; Comellas Padró, Francesc de Paula
Abstract: In this paper we find an exact analytical expression for the number of spanning trees in Apollonian networks. This parameter can be related to significant topological and dynamic properties of the networks, including percolation, epidemic spreading, synchronization, and random walks. As Apollonian networks constitute an interesting family of maximal planar graphs which are simultaneously small-world, scale-free, Euclidean and space filling, modular and highly clustered, the study of their spanning trees is of particular relevance. Our results allow also the calculation of the spanning tree entropy of Apollonian networks, which we compare with those of other graphs with the same average degree. (C) 2014 Elsevier B.V. All rights reserved.2015-03-13T11:07:20ZGeneric bifurcations of low codimension of planar Filippov Systems
http://hdl.handle.net/2117/26671
Title: Generic bifurcations of low codimension of planar Filippov Systems
Authors: Martínez-Seara Alonso, M. Teresa; Guàrdia Munarriz, Marcel; Teixeira, Marco Antonio
Abstract: In this article some qualitative and geometric aspects of non-smooth dynamical systems theory are discussed. The main aim of
this article is to develop a systematic method for studying local(and global) bifurcations in non-smooth dynamical systems. Our results deal with the classification and characterization of generic codimension-2 singularities of planar Filippov Systems as well as the presentation of the bifurcation diagrams and some dynamical consequences2015-03-12T10:45:38ZEmpty monochromatic simplices
http://hdl.handle.net/2117/26662
Title: Empty monochromatic simplices
Authors: Aichholzer, Oswin; Fabila Monroy, Ruy; Hackl, Thomas; Huemer, Clemens; Urrutia Galicia, Jorge
Abstract: Let S be a k-colored (finite) set of n points in , da parts per thousand yen3, in general position, that is, no (d+1) points of S lie in a common (d-1)-dimensional hyperplane. We count the number of empty monochromatic d-simplices determined by S, that is, simplices which have only points from one color class of S as vertices and no points of S in their interior. For 3a parts per thousand currency signka parts per thousand currency signd we provide a lower bound of and strengthen this to Omega(n (d-2/3)) for k=2.; On the way we provide various results on triangulations of point sets in . In particular, for any constant dimension da parts per thousand yen3, we prove that every set of n points (n sufficiently large), in general position in , admits a triangulation with at least dn+Omega(logn) simplices.2015-03-11T11:14:31Z