• Singular reduction of resonant Hamiltonians 

      Meyer, Kenneth Ray; Palacián Subiela, Jesús Francisco Upna; Yanguas Sayas, Patricia Upna (IOP PublishingLondon Mathematical Society, 2018)   Artículo / Artikulua
      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 ...
    • Oscillatory motions in restricted N-body problems 

      Alvarez-Ramírez, Martha; Rodríguez García, Antonio Upna; Palacián Subiela, Jesús Francisco Upna; Yanguas Sayas, Patricia Upna (Elsevier, 2018)   Artículo / Artikulua
      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 ...
    • Dynamics of axially symmetric perturbed Hamiltonians in 1:1:1 resonance 

      Carrasco, Dante; Palacián Subiela, Jesús Francisco Upna; Vidal, Claudio; Vidarte, Jhon; Yanguas Sayas, Patricia Upna (Springer, 2018)   Artículo / Artikulua
      We study the dynamics of a family of perturbed three-degree-of-freedom Hamiltonian systems which are in 1:1:1 resonance. The perturbation consists of axially symmetric cubic and quartic arbitrary polynomials. Our analysis ...
    • Asymptotic and convergent expansions for solutions of third-order linear differential equations with a large parameter 

      Ferreira, Chelo; López García, José Luis; Pérez Sinusía, Ester (Shanghai Normal UniversityWilmington Scientific Publisher, 2018)   Artículo / Artikulua  OpenAccess
      In previous papers [6–8,10], we derived convergent and asymptotic expansions of solutions of second order linear differential equations with a large parameter. In those papers we generalized and developed special cases not ...
    • Convergent expansions of the Bessel functions in terms of elementary functions 

      López García, José Luis; Pagola Martínez, Pedro Jesús (Springer US, 2018)   Artículo / Artikulua  OpenAccess
      We consider the Bessel functions Jν (z) and Yν (z) for ν > −1/2 and z ≥ 0. We derive a convergent expansion of Jν (z) in terms of the derivatives of (sin z)/z, and a convergent expansion of Yν (z) in terms of derivatives ...
    • The use of two-point Taylor expansions in singular one-dimensional boundary value problems I 

      Ferreira, Chelo; López García, José Luis; Pérez Sinusía, Ester (Elsevier, 2018)   Artículo / Artikulua
      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 ...
    • Convergent and asymptotic methods for second-order difference equations with a large parameter 

      Ferreira, Chelo; López García, José Luis; Pérez Sinusía, Ester (Springer, 2018)   Artículo / Artikulua
      We consider the second-order linear difference equation y(n+2)−2ay(n+1)−Λ2y(n)=g(n)y(n)+f(n)y(n+1) , where Λ is a large complex parameter, a≥0 and g and f are sequences of complex numbers. Two methods are proposed to find ...
    • The asymptotic expansion of the swallowtail integral in the highly oscillatory region 

      Ferreira, Chelo; López García, José Luis; Pérez Sinusía, Ester (Elsevier, 2018)   Artículo / Artikulua
      The mathematical models of many short wavelength phenomena, specially wave propagation and optical diffraction, contain, as a basic ingredient, oscillatory integrals with several nearly coincident stationary phase or saddle ...
    • Uniform convergent expansions of the Gauss hypergeometric function in terms of elementary functions 

      Ferreira, Chelo; López García, José Luis; Pérez Sinusía, Ester (Taylor & Francis, 2018)   Artículo / Artikulua
      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, Chelo; López García, José Luis; Pérez Sinusía, Ester (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 ...
    • Implementation and operational analysis of an interactive intensive care unit within a smart health context 

      López Iturri, Peio Upna; Aguirre Gallego, Erik Upna; Trigo Vilaseca, Jesús Daniel; Astrain Escola, José Javier Upna; Azpilicueta Fernández de las Heras, Leyre Upna; Serrano Arriezu, Luis Javier Upna; Villadangos Alonso, Jesús Upna; Falcone Lanas, Francisco Javier Upna (MDPI, 2018)   Artículo / Artikulua  OpenAccess
      In the context of hospital management and operation, Intensive Care Units (ICU) are one of the most challenging in terms of time responsiveness and criticality, in which adequate resource management and signal processing ...
    • 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; Vargas Rosales, César; López Iturri, Peio Upna; Aguirre Gallego, Erik Upna; Astrain Escola, José Javier Upna; Villadangos Alonso, Jesús Upna; Falcone Lanas, Francisco Javier Upna (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 ...
    • Challenges in wireless system integration as enablers for indoor context aware environments 

      López Iturri, Peio Upna; Aguirre Gallego, Erik Upna; Azpilicueta Fernández de las Heras, Leyre Upna; Astrain Escola, José Javier Upna; Villadangos Alonso, Jesús Upna; Falcone Lanas, Francisco Javier Upna (MDPI, 2017)   Artículo / Artikulua  OpenAccess
      The advent of fully interactive environments within Smart Cities and Smart Regions requires the use of multiple wireless systems. In the case of user-device interaction, which finds multiple applications such as Ambient ...
    • A simplification of the stationary phase method: application to the Anger and Weber functions 

      López García, José Luis (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 ...
    • Convergent expansions of the incomplete gamma functions in terms of elementary functions 

      Bujanda Cirauqui, Blanca Upna; López García, José Luis; Pagola Martínez, Pedro Jesús (World Scientific Publishing, 2017)   Artículo / Artikulua  OpenAccess
      We consider the incomplete gamma function γ(a,z) for Ra>0 and z∈C. We derive several convergent expansions of z−aγ(a,z) in terms of exponentials and rational functions of z that hold uniformly in z with Rz bounded from ...
    • Analytic formulas for the evaluation of the Pearcey integral 

      López García, José Luis; Pagola Martínez, Pedro Jesús (American Mathematical Society, 2017)   Artículo / Artikulua  OpenAccess
      We can find in the literature several convergent and/or asymptotic expansions of the Pearcey integral P(x, y) in different regions of the complex variables x and y, but they do not cover the whole complex x and y planes. The ...
    • Construction of additive semi-implicit Runge-Kutta methods with low-storage requirements 

      Higueras Sanz, Inmaculada Upna; Roldán Marrodán, Teodoro Upna (Springer US, 2016)   Artículo / Artikulua  OpenAccess
      Space discretization of some time-dependent partial differential equations gives rise to systems of ordinary differential equations in additive form whose terms have different stiffness properties. In these cases, implicit ...
    • Evaluation of deployment challenges of wireless sensor networks at signalized intersections 

      Azpilicueta Fernández de las Heras, Leyre Upna; López Iturri, Peio Upna; Aguirre Gallego, Erik Upna; Martínez Carrasco, Carlos; Astrain Escola, José Javier Upna; Villadangos Alonso, Jesús Upna; Falcone Lanas, Francisco Javier Upna (MDPI, 2016)   Artículo / Artikulua  OpenAccess
      With the growing demand of Intelligent Transportation Systems (ITS) for safer and more efficient transportation, research on and development of such vehicular communication systems have increased considerably in the last ...
    • On a modifcation of Olver's method: a special case 

      Ferreira, Chelo; López García, José Luis; Pérez Sinusía, Ester (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 : xm ...
    • Orthogonal basis with a conicoid first mode for shape specification of optical surfaces 

      Ferreira, Chelo; López García, José Luis; Navarro, Rafael; Pérez Sinusía, Ester (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 ...