• On a modifcation of Olver's method: a special case 

      Ferreira González, Chelo Upna; López García, José Luis Upna Orcid; Pérez Sinusía, Ester Upna Orcid (Springer US, 2016)   Artículo / Artikulua  OpenAccess
      We consider the asymptotic method designed by Olver (Asymptotics and special functions. Academic Press, New York, 1974) for linear differential equations of the second order containing a large (asymptotic) parameter : ...
    • Optimal monotonicity-preserving perturbations of a given Runge–Kutta method 

      Higueras Sanz, Inmaculada Upna Orcid; Ketcheson, David I.; Kocsis, Tihamér A. (Springer, 2018)   Artículo / Artikulua  OpenAccess
      Perturbed Runge–Kutta methods (also referred to as downwind Runge–Kutta methods) can guarantee monotonicity preservation under larger step sizes relative to their traditional Runge–Kutta counterparts. In this paper we study ...
    • Optimization and design of wireless systems for the implementation of context aware scenarios in railway passenger vehicles 

      Azpilicueta Fernández de las Heras, Leyre Upna Orcid; Astrain Escola, José Javier Upna Orcid; López Iturri, Peio Upna Orcid; Granda, Fausto; Vargas Rosales, César; Villadangos Alonso, Jesús Upna Orcid; Perallos Ruiz, Asier; Bahillo, Alfonso; Falcone Lanas, Francisco Upna Orcid (IEEE, 2017)   Artículo / Artikulua  OpenAccess
      In this paper, intra-wagon wireless communication performance is analyzed, in order to account for inherent scenario complexity in the deployment phase of wireless systems toward the implementation of a context-aware ...
    • Optimized strong stability preserving IMEX Runge-Kutta methods 

      Higueras Sanz, Inmaculada Upna Orcid; Happenhofer, Natalie; Koch, Othmar; Kupka, Friedrich (2014)   Artículo / Artikulua  OpenAccess
      We construct and analyze robust strong stability preserving IMplicit-EXplicit Runge-Kutta (IMEX RK) methods for models of flow with diffusion as they appear in astrophysics and in many other fields where equations with ...
    • Order barrier for low-storage DIRK methods with positive weights 

      Higueras Sanz, Inmaculada Upna Orcid; Roldán Marrodán, Teodoro Upna Orcid (Springer, 2018)   Artículo / Artikulua  OpenAccess
      In this paper we study an order barrier for low-storage diagonally implicit Runge-Kutta (DIRK) methods with positive weights. The Butcher matrix for these schemes, that can be implemented with only two memory registers in ...
    • Orthogonal basis for the optical transfer function 

      Ferreira González, Chelo Upna; López García, José Luis Upna Orcid; Navarro, Rafael; Pérez Sinusía, Ester Upna Orcid (Optical Society of America, 2016)   Artículo / Artikulua  OpenAccess
      We propose systems of orthogonal functions qn to represent optical transfer functions (OTF) characterized by including the diffraction-limited OTF as the first basis function q0 OTF perfect. To this end, we apply a powerful ...
    • Orthogonal basis with a conicoid first mode for shape specification of optical surfaces 

      Ferreira González, Chelo Upna; López García, José Luis Upna Orcid; Navarro, Rafael; Pérez Sinusía, Ester Upna Orcid (Optical Society of America, 2016)   Artículo / Artikulua  OpenAccess
      A rigorous and powerful theoretical framework is proposed to obtain systems of orthogonal functions (or shape modes) to represent optical surfaces. The method is general so it can be applied to different initial shapes and ...
    • Orthogonal basis with a conicoid first mode for shape specification of optical surfaces: reply 

      Ferreira González, Chelo Upna; López García, José Luis Upna Orcid; Navarro, Rafael; Pérez Sinusía, Ester Upna Orcid (Optical Society of America, 2016)   Artículo / Artikulua  OpenAccess
      We present some comments to the paper 'Orthogonal basis with a conicoid first mode for shape specification of optical surfaces: comment'.
    • Oscillatory motions in restricted N-body problems 

      Álvarez-Ramírez, Martha; Rodríguez García, Antonio Upna Orcid; Palacián Subiela, Jesús Francisco Upna Orcid; Yanguas Sayas, Patricia Upna Orcid (Elsevier, 2018)   Artículo / Artikulua  OpenAccess
      We consider the planar restricted N-body problem where the N−1 primaries are assumed to be in a central configuration whereas the infinitesimal particle escapes to infinity in a parabolic orbit. We prove the existence of ...
    • The Pearcey integral in the highly oscillatory region 

      López García, José Luis Upna Orcid; Pagola Martínez, Pedro Jesús Upna (Elsevier, 2016)   Artículo / Artikulua  OpenAccess
      We consider the Pearcey integral P(x, y) for large values of |y| and bounded values of |x|. The integrand of the Pearcey integral oscillates wildly in this region and the asymptotic saddle point analysis is complicated. ...
    • Radio characterization for ISM 2.4 GHz wireless sensor networks for judo monitoring applications 

      López Iturri, Peio Upna Orcid; Aguirre Gallego, Erik Upna Orcid; Azpilicueta Fernández de las Heras, Leyre Upna Orcid; Astrain Escola, José Javier Upna Orcid; Villadangos Alonso, Jesús Upna Orcid; Falcone Lanas, Francisco Javier Upna Orcid (MDPI, 2014)   Artículo / Artikulua  OpenAccess
      In this work, the characterization of the radio channel for ISM 2.4GHz Wireless Sensor Networks (WSNs) for judo applications is presented. The environments where judo activity is held are usually complex indoor scenarios ...
    • Radio wave propagation and WSN deployment in complex utility tunnel environments 

      Celaya Echarri, Mikel Upna Orcid; Azpilicueta Fernández de las Heras, Leyre Upna Orcid; López Iturri, Peio Upna Orcid; Picallo Guembe, Imanol Upna Orcid; Aguirre Gallego, Erik Upna Orcid; Astrain Escola, José Javier Upna Orcid; Villadangos Alonso, Jesús Upna Orcid; Falcone Lanas, Francisco Javier Upna Orcid (MDPI, 2020)   Artículo / Artikulua  OpenAccess
      The significant growth of wireless communications systems in the last years has led to the adoption of a wide range of applications not only for the general public but, also, including utilities and administrative authorities. ...
    • Representations of hypergeometric functions for arbitrary parameter values and their use 

      Karp, D. B.; López García, José Luis Upna Orcid (2017)   Artículo / Artikulua  OpenAccess
      Integral representations of hypergeometric functions proved to be a very useful tool for studying their properties. The purpose of this paper is twofold. First, we extend the known representations to arbitrary values of ...
    • Scalability approaches for causal multicast: a survey 

      Juan Marín, Rubén de; Decker, Hendrik; Armendáriz Íñigo, José Enrique Upna Orcid; Bernabéu Aubán, José M.; Muñoz Escoí, Francesc D. (Springer, 2016)   Artículo / Artikulua  OpenAccess
      Many distributed services need to be scalable: internet search, electronic commerce, e-government... In order to achieve scalability those applications rely on replicated components. Because of the dynamics of growth and ...
    • A simplification of the stationary phase method: application to the Anger and Weber functions 

      López García, José Luis Upna Orcid (Kent State UniversityJohann Radon Institute (RICAM), 2017)   Artículo / Artikulua  OpenAccess
      The main difficulty in the practical use of the stationary phase method in asymptotic expansions of integrals is originated by a change of variables. The coefficients of the asymptotic expansion are the coefficients of the ...
    • Singular reduction of resonant Hamiltonians 

      Meyer, Kenneth Ray; Palacián Subiela, Jesús Francisco Upna Orcid; Yanguas Sayas, Patricia Upna Orcid (IOP PublishingLondon Mathematical Society, 2018)   Artículo / Artikulua  OpenAccess
      We investigate the dynamics of resonant Hamiltonians with n degrees of freedom to which we attach a small perturbation. Our study is based on the geometric interpretation of singular reduction theory. The flow of the ...
    • Spatial characterization of radio propagation channel in urban vehicle-to-infrastructure environments to support WSNs deployment 

      Granda, Fausto; Azpilicueta Fernández de las Heras, Leyre Upna Orcid; Vargas Rosales, César; López Iturri, Peio Upna Orcid; Aguirre Gallego, Erik Upna Orcid; Astrain Escola, José Javier Upna Orcid; Villadangos Alonso, Jesús Upna Orcid; Falcone Lanas, Francisco Javier Upna Orcid (MDPI, 2017)   Artículo / Artikulua  OpenAccess
      Vehicular ad hoc Networks (VANETs) enable vehicles to communicate with each other as well as with roadside units (RSUs). Although there is a significant research effort in radio channel modeling focused on vehicle-to-vehicle ...
    • Uniform convergent expansions of the Gauss hypergeometric function in terms of elementary functions 

      Ferreira González, Chelo Upna; López García, José Luis Upna Orcid; Pérez Sinusía, Ester Upna Orcid (Taylor & Francis, 2018)   Artículo / Artikulua  OpenAccess
      We consider the hypergeometric function 2F1(a, b; c; z) for z ∈ C \ [1,∞). For Ra ≥ 0, we derive a convergent expansion of 2F1(a, b; c; z) in terms of the function (1 − z)−a and of rational functions of z that is uniformly ...
    • Uniform representation of the incomplete beta function in terms of elementary functions 

      Ferreira González, Chelo Upna; López García, José Luis Upna Orcid; Pérez Sinusía, Ester Upna Orcid (Kent State UniversityJohann Radon Institute (RICAM), 2018)   Artículo / Artikulua  OpenAccess
      We consider the incomplete beta function Bz(a, b) in the maximum domain of analyticity of its three variables: a, b, z ∈ C, −a /∈ N, z /∈ [1, ∞). For <b ≤ 1 we derive a convergent expansion of z−aBz(a, b) in terms of the ...
    • The use of two-point Taylor expansions in singular one-dimensional boundary value problems I 

      Ferreira González, Chelo Upna; López García, José Luis Upna Orcid; Pérez Sinusía, Ester Upna Orcid (Elsevier, 2018)   Artículo / Artikulua  OpenAccess
      We consider the second-order linear differential equation (x + 1)y′′ + f(x)y′ + g(x)y = h(x) in the interval (−1, 1) with initial conditions or boundary conditions (Dirichlet, Neumann or mixed Dirichlet-Neumann). The ...

      El Repositorio ha recibido la ayuda de la Fundación Española para la Ciencia y la Tecnología para la realización de actividades en el ámbito del fomento de la investigación científica de excelencia, en la Línea 2. Repositorios institucionales (convocatoria 2020-2021).
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