DSpace Collection:
http://hdl.handle.net/2117/3918
2015-03-01T23:38:24ZJ2 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.On the asymptotic spatial behaviour of the solutions of the nerve system
http://hdl.handle.net/2117/26512
Title: On the asymptotic spatial behaviour of the solutions of the nerve system
Authors: Leseduarte Milán, María Carme; Quintanilla de Latorre, Ramón
Abstract: In this paper we investigate the asymptotic spatial behavior of the solutions for several models for the nerve fibers.
First, our analysis deals with the coupling of two parabolic equations. We prove that, under suitable assumptions on the coefficients
and the nonlinear function, the decay is similar to the one corresponding to the heat equation. A limit case of this system
corresponds to the coupling of a parabolic equation with an ordinary differential equation. In this situation, we see that for suitable
boundary conditions the solution ceases to exist for a finite value of the spatial variable. Next two sections correspond to
the coupling of a hyperbolic/parabolic and hyperbolic/ordinary differential problems. For the first one we obtain that the decay
is like an exponential of a second degree polynomial in the spatial variable. In the second one, we prove a similar behaviour to
the one corresponding to the wave equation. In these two sections we use in a relevant way an exponentially weighted Poincaré
inequality which has been revealed very useful in several thermal and mechanical problems. This kind of results have relevance
to understand the propagation of perturbations for nerve models.2015-02-25T14:52:52ZThe number of empty four-gons in random point sets
http://hdl.handle.net/2117/26500
Title: The number of empty four-gons in random point sets
Authors: Fabila-Monroy, Ruy; Huemer, Clemens; Mitsche, Dieter
Abstract: Let S be a set of n points distributed uniformly and independently in the unit square. Then the expected number of empty four-gons with vertices from S is T(n^2 log¿ n). A four-gon is empty if it contains no points of S in its interior.2015-02-25T11:16:10ZPassive and hybrid mitigation of potential near-fault inner pounding of a self-braking seismic isolator
http://hdl.handle.net/2117/26489
Title: Passive and hybrid mitigation of potential near-fault inner pounding of a self-braking seismic isolator
Authors: Abdel Kareem Moustafa, Mohamed Ismail; Rodellar Benedé, José; Pozo Montero, Francesc
Abstract: A seismic isolated structure is usually a long-period structural system, which may encounter a low-frequency resonance problem when subjected to a near-fault earthquake that usually has a long-period pulse-like waveform. This long-period wave component may result in an enlargement of the base displacement and a decrease of the isolation efficiency. To overcome this problem, a rolling-based seismic isolator, referred to as roll-n-cage (RNC) isolator, has been recently proposed. The RNC isolator has a built-in buffer (braking) mechanism that limits the peak isolator displacements under severe earthquakes and prevents adjacent structural pounding. This paper addresses the problem of passive and hybrid mitigation of the potential inner pounding of the self-braking RNC isolator under near-fault earthquakes. Numerical results show that the RNC isolator can intrinsically limit the isolator displacements under near-fault earthquakes with less severe inner pounding using additional hysteretic damping and active control forces2015-02-24T13:05:35ZEl sistema alimentario global: I - definición de un espacio
http://hdl.handle.net/2117/26474
Title: El sistema alimentario global: I - definición de un espacio
Authors: Clotet, Ramon; Colomer Xena, Yvonne; Jarauta Bragulat, Eusebio; Mayor Zaragoza, Federico
Abstract: Los autores desarrollan su modelo de sistema alimentario global, presentado conceptualmente
en anteriores publicaciones, basado en cuatro ejes básicos (disponibilidad, economía, política
y saber) dándole una estructura comprensible, abierta y en la que se le aplica una metodología
matemática que permite conocer la evolución de los parámetros y su prospectiva.
Para ello, en el presente trabajo se pasa de los conceptos cualitativos a los cuantitativos.
Cada eje se descompone, en tres subejes dando un total de 12, que identifican aspectos específicos
de los primarios y que definen en este espacio las actividades y conceptos fundamentales
del sistema agroalimentario y de tal forma que puedan seguir desarrollándose sus
contenidos en aspectos de aún más detalle, en un desarrollo fractal de base tetraédrica.
Para cada subeje se propone un primer parámetro de evaluación en base a valores en unidades,
obtenibles en unidades de tiempo, habitualmente años, de datos fiables publicados
y compatibles con el modelo de estudios evolutivos y prospectivos presentados en el que
se propone una variable vectorial para cada eje que toma valores en el simplex de tres partes
y ajuste a un modelo lineal en coordenadas ILR (isometric logratio transformation).
El modelo normaliza una estructura que da relieve al espacio agroalimentario global y permite
realizar estrategias prospectivas sobre el mismo en cada parámetro y entre ellos.2015-02-23T17:02:04ZAbastecimiento y saneamiento en zonas rurales de países en desarrollo. Situación actual y desafíos para el futuro
http://hdl.handle.net/2117/26457
Title: Abastecimiento y saneamiento en zonas rurales de países en desarrollo. Situación actual y desafíos para el futuro
Authors: Jiménez, Alejandro; Marín, Gonzalo; Pérez Foguet, Agustí2015-02-23T09:15:35ZThe degree/diameter problem in maximal planar bipartite graphs
http://hdl.handle.net/2117/26448
Title: The degree/diameter problem in maximal planar bipartite graphs
Authors: Dalfó Simó, Cristina; Huemer, Clemens; Salas Piñon, Julián
Abstract: The (¿;D) (degree/diameter) problem consists of nding the largest possible number of vertices n among all the graphs with maximum degree ¿ and diameter D. We consider the (¿;D) problem for maximal planar bipartite graphs, that are simple planar graphs in which every face is a quadrangle. We obtain that for the (¿; 2) problem, the number of vertices is n = ¿+2; and for the (¿; 3) problem, n = 3¿¿1 if ¿ is odd and n = 3¿ ¿ 2 if ¿ is even. Then, we study the general case (¿;D)
and obtain that an upper bound on n is approximately 3(2D + 1)(¿ ¿ 2)¿D=2¿ and another one is C(¿ ¿ 2)¿D=2¿ if ¿ D and C is a sufficiently large constant. Our upper bound improve for our kind of graphs the one given by Fellows, Hell and Seyffarth for general planar graphs. We also give a lower bound on n for maximal planar bipartite graphs, which is approximately (¿ ¿ 2)k if D = 2k, and 3(¿ ¿ 3)k if D = 2k + 1, for ¿ and D sufficiently large in both cases.2015-02-20T12:42:33ZForeword to special issue on ‘‘Qualitative Methods in Engineering Science’’
http://hdl.handle.net/2117/26438
Title: Foreword to special issue on ‘‘Qualitative Methods in Engineering Science’’
Authors: Quintanilla de Latorre, Ramón; Fu, Yibin2015-02-19T16:17:32ZStudy of Spanish mining accidents using data mining techniques
http://hdl.handle.net/2117/26427
Title: Study of Spanish mining accidents using data mining techniques
Authors: Sanmiquel Pera, Lluís; Rossell Garriga, Josep Maria; Vintró Sánchez, Carla
Abstract: Mining is an economic sector with a high number of accidents. Mines are hazardous places and workers can suffer a wide variety of injuries. Utilizing a database composed of almost 70,000 occupational accidents and fatality reports corresponding to the decade 2003–2012 in the Spanish mining sector, the paper analyzes the main causes of those accidents. To carry out the study, powerful statistical tools have been applied, such as Bayesian classi¿ers, decision trees or contingency tables, among other data mining techniques. Statistical analyses have been performed using Weka software and behavioral patterns based on certain rules have been obtained. From these rules, some conclusions are extracted which can help to develop suitable prevention policies to reduce injuries and fatalities.2015-02-19T11:52:16ZPhase-lag heat conduction: decay rates for limit problems and well-posedness
http://hdl.handle.net/2117/26420
Title: Phase-lag heat conduction: decay rates for limit problems and well-posedness
Authors: Borgmeyer, Karin; Quintanilla de Latorre, Ramón; Racke, Reinhard
Abstract: In two recent papers, the authors have studied conditions on the relaxation parameters in order to guarantee the stability or instability of solutions for the Taylor approximations to dual-phase-lag and three-phase-lag heat conduction equations. However, for several limit cases relating to the parameters, the kind of stability was unclear. Here, we analyze these limit cases and clarify whether we can expect exponential or slow decay for the solutions. Moreover, rather general well-posedness results for three-phase-lag models are presented. Finally, the exponential stability expected by spectral analysis is rigorously proved exemplarily.
Description: The final publication is available at Springer via http://dx.doi.org/10.1007/s00028-014-0242-6.2015-02-18T17:18:03ZHölder stability in type III thermoelastodynamics
http://hdl.handle.net/2117/26416
Title: Hölder stability in type III thermoelastodynamics
Authors: Leseduarte Milán, María Carme; Quintanilla de Latorre, Ramón
Abstract: This note is concerned with the linear (and linearized) Type III thermoelastodynamic theory proposed by Green and Naghdi. We here assume that the mass density is positive and the thermal conductivity tensor is positive definite. However, we do not assume the positivity of any other tensor. In this situation, we obtain Holder continuous dependence results on the supply terms. We also sketch how to prove the continuous dependence on the initial data.
Description: Electronic version of an article published as "Archive of applied mechanics", vol. 84 nº 9-11, October 2014, p. 1465-1476. DOI No 10.1007/s00419-014-0827-0.2015-02-18T15:34:37ZApplication of a revised Water Poverty Index to target the water poor
http://hdl.handle.net/2117/26371
Title: Application of a revised Water Poverty Index to target the water poor
Authors: Giné Garriga, Ricard; Pérez Foguet, Agustí
Abstract: The Water Poverty Index (WPI) has been recognized as a useful tool in policy analysis. The index integrates various physical, social and environmental aspects to enable more holistic assessment of water resources. However, soundness of this tool relies on two complementary aspects: (i) inadequate techniques employed in index construction would produce unreliable results, and (ii) poor dissemination of final outcome would reduce applicability of the index to influence policy-making. From a methodological point of view, a revised alternative to calculate the index was developed in a previous study. This paper is therefore concerned not with the method employed in index construction, but with how the composite can be applied to support decision-making processes. In particular, the paper examines different approaches to exploit the index as a policy tool. A number of alternatives to disseminate achieved results are presented. The implications of applying the composite at different spatial scales are highlighted. Turkana District, in Kenya has been selected as initial case study to test the applicability and validity of the index. The paper concludes that the WPI approach provides a relevant tool for guiding appropriate action and policy-making towards more equitable allocation of water resources.2015-02-16T14:24:18ZMonitoring access to water in rural areas based on the human right to water framework: a local level case study in Nicaragua
http://hdl.handle.net/2117/26370
Title: Monitoring access to water in rural areas based on the human right to water framework: a local level case study in Nicaragua
Authors: Flores, O.; Jiménez Fernández de Palencia, A.; Pérez Foguet, Agustí
Abstract: Much effort has gone into the recognition of the human right to water. Without doubt,
this milestone influences governance and decision making processes at many scales so
it is essential now to shift the discussion from the legal and conceptual framework to
practice. Along this line, the article proposes a methodology for monitoring access to
water in rural areas using the framework of this human right. The practicality of the
approach is demonstrated by a case study carried out in Nicaragua. Different criteria of
the right to water were included in surveys and structured interviews that were
conducted in rural households and water committees, respectively. A discussion
analyzes the advantages and challenges of using this framework. Finally, the approach
provides elements for policy making that can be used by different stakeholders in the
development and human rights sectors.2015-02-16T14:20:54ZQuality and year-round availability of water delivered by improved water points in rural Tanzania: effects on coverage
http://hdl.handle.net/2117/26368
Title: Quality and year-round availability of water delivered by improved water points in rural Tanzania: effects on coverage
Authors: Jiménez Fernández de Palencia, Alejandro; Pérez Foguet, Agustí
Abstract: This paper reports the findings of three water point mapping (WPM) studies carried out in three rural districts of Tanzania covering 3,363 water points. The methodology was designed to estimate the influence that consideration of the quality of the water supplied and the year-round functionality of each water point would have on each district's coverage figures. To this end, the study included measurements of basic quality parameters (692 analyses) and characterisation of the year-round continuity of service, in addition to the data collected in standard WPM campaigns. Both the quality and year-round continuity results were analysed in a disaggregated form by water point technology. The results show that 22% of the improved water points analysed had more than 10 CFU (colony-forming units)/100 ml of water and 19% were seasonal. Moreover, water service coverage in the districts studied fell 40% on average when quality and year-round continuity were considered. There is a strong need to include these basic factors in the minimum standards to be delivered and monitored in rural areas. Simple and efficient methodologies for including quality and year-round continuity measurements in the information routines, such as the one presented here, are a necessary step to this end.2015-02-16T14:18:15Z