Now showing items 4-23 of 75

    • Binary relations coming from solutions of functional equations: orderings and fuzzy subsets 

      Campión Arrastia, María Jesús Upna; Miguel Turullols, Laura de Upna; García Catalán, Olga Raquel Upna; Induráin Eraso, Esteban Upna; Abrísqueta Usaola, Francisco Javier Upna (World Scientific Publishing Company, 2017)   Artículo / Artikulua  OpenAccess
      We analyze the main properties of binary relations, defined on a nonempty set, that arise in a natural way when dealing with real-valued functions that satisfy certain classical functional equations on two variables. We ...
    • 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 microring filters for differential group delay applications 

      Doménech, D.; Chamorro Posada, P.; Fraile Pelaez, F.J.; Erro Betrán, María José Upna; Tainta Ausejo, Santiago Upna; Muriel, M.A.; Baños, R.; Bolten, J.; Kleinjans, H. (IEEEOptical Society of America, 2017)   Artículo / Artikulua  OpenAccess
      The longitudinal offset technique permits to improve the accuracy of the coupling coefficients of integrated directional couplers and provides designs that can be easily implemented with current fabrication tolerances. ...
    • Comparison between capacitive and microstructured optical fiber soil moisture sensors 

      López Aldaba, Aitor Upna; López Torres, Diego Upna; Campo Bescós, Miguel Ángel Upna; López Rodríguez, José Javier; Yerro Lizarazu, David; Elosúa Aguado, César Upna; Arregui San Martín, Francisco Javier Upna; Auguste, Jean-Louis; Jamier, Raphael; Roy, Philippe; López-Amo Sáinz, Manuel Upna (MDPI, 2018)   Artículo / Artikulua  OpenAccess
      Soil moisture content has always been an important parameter to control because it is a deterministic factor for site-specific irrigation, seeding, transplanting, and compaction detection. In this work, a discrete sensor ...
    • A comprehensive model for lithium-ion batteries: from the physical principles to an electrical model 

      Berrueta Irigoyen, Alberto; Urtasun Erburu, Andoni Upna; Ursúa Rubio, Alfredo Upna; Sanchis Gúrpide, Pablo Upna (Elsevier, 2018)   Artículo / Artikulua
      The growing interest in e-mobility and the increasing installation of renewable energy-based systems are leading to rapid improvements in lithium-ion batteries. In this context, battery manufacturers and engineers require ...
    • Computation of traffic time series for large populations of IoT devices 

      Izal Azcárate, Mikel Upna; Morató Osés, Daniel Upna; Magaña Lizarrondo, Eduardo Upna; García-Jiménez, Santiago Upna (MDPI, 2018)   Artículo / Artikulua  OpenAccess
      En este artículo se estudian las tecnicas para clasificar paquetes de tráfico de red en múltiples clases orientadas a la realización de series temporales de tráfico en escenarios de un elevado numero de clases como pueden ...
    • Convolution lattices 

      Miguel Turullols, Laura de Upna; Bustince Sola, Humberto Upna; De Baets, Bernard (Elsevier, 2018)   Artículo / Artikulua
      We propose two convolution operations on the set of functions between two bounded lattices and investigate the algebraic structure they constitute, in particular the lattice laws they satisfy. Each of these laws requires ...
    • Cyclic coding for Brillouin optical time-domain analyzers using probe dithering 

      Iribas Pardo, Haritz Upna; Loayssa Lara, Alayn Upna; Sauser, Florian; Llera, Miguel; Le Floch, Sébastien (Optical Society of America, 2017)   Artículo / Artikulua  OpenAccess
      We study the performance limits of mono-color cyclic coding applied to Brillouin optical time-domain analysis (BOTDA) sensors that use probe wave dithering. BOTDA analyzers with dithering of the probe use a dual-probe-sideband ...
    • Description of bow-tie nanoantennas excited by localized emitters using conformal transformation 

      Pacheco Peña, Víctor Upna; Beruete Díaz, Miguel Upna; Fernández Domínguez, Antonio I.; Luo, Yu; Navarro Cía, Miguel Upna (American Chemical Society, 2016)   Artículo / Artikulua  OpenAccess
      The unprecedented advance experienced by nano- fabrication techniques and plasmonics research over the past few years has made possible the realization of nanophotonic systems entering into the so-called strong coupling ...
    • Dispersion properties of an elliptical patch with cross shaped aperture for synchronized propagation of transverse magnetic and electric surface waves 

      Tellechea Pereda, Amagoia Upna; Ederra Urzainqui, Íñigo Upna; Gonzalo García, Ramón Upna; Iriarte Galarregui, Juan Carlos Upna (MDPI, 2018)   Artículo / Artikulua  OpenAccess
      This paper presents a novel pixel geometry for the implementation of metasurfaces requiring synchronized phase propagation of transverse magnetic (TM) and transverse electric (TE) modes. The pixel is composed by an elliptical ...
    • Equivalent and efficient optimization models for an industrial discrete event system with alternative structural configurations 

      Latorre Biel, Juan Ignacio; Jiménez Macías, Emilio; Pérez de la Parte, Mercedes (Hindawi / Wiley, 2018)   Artículo / Artikulua  OpenAccess
      Discrete event systems in applications, such as industry and supply chain,may show a very complex behavior. For this reason, their design and operation may be carried out by the application of optimization techniques for ...
    • 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 ...
    • Evolution in time of L-fuzzy context sequences 

      Alcalde, Cristina; Burusco Juandeaburre, Ana Upna; Bustince Sola, Humberto Upna; Jurío Munárriz, Aránzazu Upna; Sanz Delgado, José Antonio Upna (Elsevier, 2016)   Artículo / Artikulua  OpenAccess
      In this work, we consider a complete lattice L and we study L-fuzzy context sequences which represent the evolution in time of an L-fuzzy context. To carry out this study, in the first part of the paper, we consider n-ary ...
    • Experimental and computational study on thermoelectric generators using thermosyphons with phase change as heat exchangers 

      Araiz Vega, Miguel Upna; Martínez Echeverri, Álvaro Upna; Astrain Ulibarrena, David Upna; Aranguren Garacochea, Patricia Upna (Elsevier, 2017)   Artículo / Artikulua  OpenAccess
      An important issue in thermoelectric generators is the thermal design of the heat exchangers since it can improve their performance by increasing the heat absorbed or dissipated by the thermoelectric modules. Due to its ...
    • Experimental realization of an epsilon-near-zero graded-index metalens at terahertz frequencies 

      Pacheco Peña, Víctor Upna; Engheta, Nader; Kuznetsov, Sergei A.; Gentselev, Alexandr; Beruete Díaz, Miguel Upna (American Physical Society, 2017)   Artículo / Artikulua  OpenAccess
      The terahertz band has been historically hindered by the lack of efficient generators and detectors, but a series of recent breakthroughs have helped to effectively close the “terahertz gap.” A rapid development of terahertz ...
    • Experimental validation of a Ku-band dual circularly polarized metasurface antenna 

      Tellechea Pereda, Amagoia Upna; Caminita, Francesco; Martini, Enrica; Ederra Urzainqui, Íñigo Upna; Teniente Vallinas, Jorge Upna; Iriarte, Juan Carlos; Gonzalo, Ramón; Maci, Stefano (IEEE, 2018)   Artículo / Artikulua  OpenAccess
      The experimental validation of a Ku-band dual circularly polarized (CP) broadside-beam metasurface (MTS) antenna is presented. A radially modulated anisotropic single layer MTS has been synthesised employing sub-wavelength ...
    • Extraordinary THz transmission with a small beam spot: the leaky wave mechanism 

      Navarro Cía, Miguel Upna; Pacheco Peña, Víctor Upna; Kuznetsov, Sergei A.; Beruete Díaz, Miguel Upna (Wiley, 2018)   Artículo / Artikulua  OpenAccess
      The discovery of extraordinary optical transmission (EOT) through patterned metallic foils in the late 1990s was decisive for the development of plasmonics and cleared the path to employ small apertures for a variety of ...
    • Fabrication of Bragg gratings on the end facet of standard optical fibers by sputtering the same material 

      Ascorbe Muruzabal, Joaquín Upna; Corres Sanz, Jesús María Upna; del Villar, Ignacio Upna; Arregui San Martín, Francisco Javier Upna; Matías Maestro, Ignacio Upna (IEEE, 2016)   Artículo / Artikulua  OpenAccess
      A sputtering process has been applied to deposit quarter-wavelength stacks on the end facet of cleaved optical fibers by using only one sputtering target. Standard multimode optical fibers were used as substrates to fabricate ...
    • A framework for radial data comparison and its application to fingerprint analysis 

      Marco Detchart, Cedric Upna; Cerrón González, Juan Upna; Miguel Turullols, Laura de Upna; López Molina, Carlos Upna; Bustince Sola, Humberto Upna; Galar Idoate, Mikel Upna (Elsevier, 2016)   Artículo / Artikulua  OpenAccess
      This work tackles the comparison of radial data, and proposes comparison measures that are further applied to fingerprint analysis. First, we study the similarity of scalar and non-scalar radial data, elaborated on previous ...
    • Fuzzy rule-based classification systems for multi-class problems using binary decomposition strategies: on the influence of n-dimensional overlap functions in the fuzzy reasoning method 

      Elkano Ilintxeta, Mikel Upna; Galar Idoate, Mikel Upna; Sanz Delgado, José Antonio Upna; Bustince Sola, Humberto Upna (Elsevier, 2016)   Artículo / Artikulua  OpenAccess
      Multi-class classification problems appear in a broad variety of real-world problems, e.g., medicine, genomics, bioinformatics, or computer vision. In this context, decomposition strategies are useful to increase the ...