Now showing items 1-20 of 57

    • Analysis of radio wave propagation for ISM 2.4 GHz wireless sensor networks in inhomogeneous vegetation environments 

      Azpilicueta Fernández de las Heras, Leyre Upna; López Iturri, Peio Upna; Aguirre Gallego, Erik Upna; Mateo Zozaya, Ignacio; Astrain Escola, José Javier Upna; Villadangos Alonso, Jesús Upna; Falcone Lanas, Francisco Javier Upna (MDPI, 2014)   Artículo / Artikulua  OpenAccess
      The use of wireless networks has experienced exponential growth due to the improvements in terms of battery life and low consumption of the devices. However, it is compulsory to conduct previous radio propagation analysis ...
    • Analysis of wireless sensor network topology and estimation of optimal network deployment by deterministic radio channel characterization 

      Aguirre Gallego, Erik Upna; López Iturri, Peio Upna; Azpilicueta Fernández de las Heras, Leyre Upna; Astrain Escola, José Javier Upna; Villadangos Alonso, Jesús Upna; Falcone Lanas, Francisco Javier Upna (MDPI, 2015)   Artículo / Artikulua  OpenAccess
      One of the main challenges in the implementation and design of context-aware scenarios is the adequate deployment strategy for Wireless Sensor Networks (WSNs), mainly due to the strong dependence of the radiofrequency ...
    • Analytic formulas for the evaluation of the Pearcey integral 

      López García, José Luis Upna; Pagola Martínez, Pedro Jesús Upna (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 ...
    • Asymptotic and convergent expansions for solutions of third-order linear differential equations with a large parameter 

      Ferreira, Chelo; López García, José Luis Upna; Pérez Sinusía, Ester Upna (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 ...
    • Asymptotic behaviour of the Urbanik semigroup 

      Berg, Christian; López García, José Luis Upna (Elsevier, 2015)   Artículo / Artikulua  OpenAccess
      We revisit the product convolution semigroup of probability densities ec(t); c > 0 on the positive half-line with moments (n!)c and determine the asymptotic behaviour of ec for large and small t > 0. This shows that (n!)c ...
    • The asymptotic expansion of the swallowtail integral in the highly oscillatory region 

      Ferreira, Chelo; López García, José Luis Upna; Pérez Sinusía, Ester Upna (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 ...
    • Avoiding the order reduction when solving second-order in time PDEs with Fractional Step Runge–Kutta–Nyström methods 

      Moreta, M. Jesús; Bujanda Cirauqui, Blanca Upna; Jorge Ulecia, Juan Carlos Upna (Elsevier, 2016)   Artículo / Artikulua  OpenAccess
      We study some of the main features of Fractional Step Runge–Kutta–Nyström methods when they are used to integrate Initial–Boundary Value Problems of second order in time, in combination with a suitable spatial discretization. ...
    • 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 ...
    • Characterization of wireless channel impact on wireless sensor network performance in public transportation buses 

      Azpilicueta Fernández de las Heras, Leyre Upna; López Iturri, Peio Upna; Aguirre Gallego, Erik Upna; Astrain Escola, José Javier Upna; Villadangos Alonso, Jesús Upna; Zubiri Segura, Cristóbal; Falcone Lanas, Francisco Javier Upna (IEEE, 2015)   Artículo / Artikulua  OpenAccess
      Wireless communications systems are growing rapidly during the last two decades and they are gaining a significant role for multiple communication tasks within public transportation buses. In this work, the impact of ...
    • 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 ...
    • Convergent and asymptotic expansions of solutions of differential equations with a large parameter: Olver cases II and III 

      Ferreira González, Chelo Upna; López García, José Luis Upna; Pérez Sinusía, Ester Upna (Rocky Mountain Mathematics Consortium, 2015)   Artículo / Artikulua  OpenAccess
      This paper continues the investigation initiated in [Lopez, 2013]. We consider the asymptotic method designed by F. Olver [Olver, 1974] for linear differential equations of the second order containing a large (asymptotic) ...
    • Convergent and asymptotic expansions of the Pearcey integral 

      López García, José Luis Upna; Pagola Martínez, Pedro Jesús Upna (Elsevier, 2015)   Artículo / Artikulua  OpenAccess
      We consider the Pearcey integral P(x; y) for large values of |x|, x, y ∈ C. We can find in the literature several convergent or asymptotic expansions in terms of elementary and special functions, with different levels ...
    • Convergent and asymptotic methods for second-order difference equations with a large parameter 

      Ferreira, Chelo; López García, José Luis Upna; Pérez Sinusía, Ester Upna (Springer, 2018)   Artículo / Artikulua  OpenAccess
      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 ...
    • Convergent asymptotic expansions of Charlier, Laguerre and Jacobi polynomials 

      López García, José Luis Upna; Temme, Nico M. (Cambridge University Press, 2004)   Artículo / Artikulua  OpenAccess
      Convergent expansions are derived for three types of orthogonal polynomials: Charlier, Laguerre and Jacobi. The expansions have asymptotic properties for large values of the degree. The expansions are given in terms of ...
    • Convergent expansions of the Bessel functions in terms of elementary functions 

      López García, José Luis Upna; Pagola Martínez, Pedro Jesús Upna (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 ...
    • Convergent expansions of the incomplete gamma functions in terms of elementary functions 

      Bujanda Cirauqui, Blanca Upna; López García, José Luis Upna; Pagola Martínez, Pedro Jesús Upna (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 ...
    • Decoupling mixed finite elements on hierarchical triangular grids for parabolic problems 

      Arrarás Ventura, Andrés Upna; Portero Egea, Laura Upna (Elsevier, 2018)   Artículo / Artikulua  OpenAccess
      In this paper, we propose a numerical method for the solution of time-dependent flow problems in mixed form. Such problems can be efficiently approximated on hierarchical grids, obtained from an unstructured coarse ...
    • Design and performance analysis of wireless body area networks in complex indoor e-Health hospital environments for patient remote monitoring 

      Aguirre Gallego, Erik Upna; López Iturri, Peio Upna; Azpilicueta Fernández de las Heras, Leyre Upna; Rivarés Garasa, Carmen; Astrain Escola, José Javier Upna; Villadangos Alonso, Jesús Upna; Falcone Lanas, Francisco Javier Upna (SAGE, 2016)   Artículo / Artikulua  OpenAccess
      In this article, the design and performance analysis of wireless body area network–based systems for the transmission of medical information readable in an android-based application deployed within complex indoor e-Health ...
    • Dynamics of axially symmetric perturbed Hamiltonians in 1:1:1 resonance 

      Carrasco, Dante; Palacián Subiela, Jesús Francisco Upna; Vidal Díaz, Claudio; Vidarte, Jhon; Yanguas Sayas, Patricia Upna (Springer, 2018)   Artículo / Artikulua  OpenAccess
      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 ...
    • Educational games to enhance museum visits for schools 

      Bossavit, Benoît Upna; Pina Calafi, Alfredo Upna; Sánchez Gil, Isabel Upna; Urtasun, Aitziber (National Taiwan Normal University, 2018)   Artículo / Artikulua  OpenAccess
      Museums usually look for new educational tools to enhance their exhibition. The Oteiza's museum in Navarre (Spain) especially gives importance to the dissemination of Jorge Oteiza's work to children at schools. Consequently, ...