Now showing items 64-83 of 110

    • Nanofabrication of phase-shifted Bragg gratings on the end facet of multimode fiber towards development of optical filters and sensors 

      Gallego, E.E.; Ascorbe Muruzabal, Joaquín Upna; Del Villar, Ignacio Upna; Corres Sanz, Jesús María Upna; Matías Maestro, Ignacio Upna (Elsevier, 2018)   Artículo / Artikulua
      This work describes the process of nanofabrication of phase-shifted Bragg gratings on the end facet of a multimode optical fiber with a pulsed DC sputtering system based on a single target. Several structures have been ...
    • New measures for comparing matrices and their application to image processing 

      Sesma Sara, Mikel Upna; Miguel Turullols, Laura de Upna; Pagola Barrio, Miguel Upna; Burusco Juandeaburre, Ana Upna; Mesiar, Radko; Bustince Sola, Humberto Upna (Elsevier, 2018)   Artículo / Artikulua
      In this work we present the class of matrix resemblance functions, i.e., functions that measure the difference between two matrices. We present two construction methods and study the properties that matrix resemblance ...
    • Non-local effects in Brillouin optical time-domain analysis sensors 

      Iribas Pardo, Haritz Upna; Urricelqui Polvorinos, Javier Upna; Mompó Roselló, Juan José Upna; Mariñelarena Ollacarizqueta, Jon Upna; Loayssa Lara, Alayn Upna (MDPI, 2017)   Artículo / Artikulua  OpenAccess
      Brillouin optical time-domain analysis (BOTDA) sensors have great potential to provide distributed measurements of temperature and strain over large structures with high spatial resolution and measurement precision. However, ...
    • Nonbianisotropic complementary split ring resonators as angular selective metasurfaces 

      Rodríguez Ulibarri, Pablo Upna; Beruete Díaz, Miguel Upna (Optical Society of America, 2017)   Artículo / Artikulua  OpenAccess
      In this work, a metasurface with unconventional angular performance and composed by a nonbianisotropic complementary split ring resonator (NB-CSRR) is analyzed numerically and experimentally. A numerical study comparing ...
    • On the performance of an ENZ-based sensor using transmission line theory and effective medium approach 

      Pacheco-Peña, Víctor Upna; Beruete Díaz, Miguel Upna; Rodríguez Ulibarri, Pablo Upna; Engheta, Nader (IOP Publishing, 2019)   Artículo / Artikulua  OpenAccess
      In this paper we perform an in-depth theoretical studyofa sensing platform based on epsilon-near- zero (ENZ) metamaterials. The structure proposed for sensing is a narrow metallic waveguide channel. An equivalent circuit ...
    • On the performance of the zoned fishnet metamaterial lens with positive and negative reference phase 

      Pacheco-Peña, Víctor Upna; Minin, Igor V.; Minin, Oleg V.; Beruete Díaz, Miguel Upna (IEEE, 2016)   Artículo / Artikulua  OpenAccess
      In this letter, several converging fishnet metalenses are designed using both the zoning and reference phase techniques. They are engineered with a focal length of 1.5λ0 at the design frequency of 55 GHz (λ0 = 5.45 mm) at ...
    • Optical fibre sensors using graphene-based materials: a review 

      Hernáez Sáenz de Zaitigui, Miguel Upna; Ruiz Zamarreño, Carlos Upna; Melendi Espina, Sonia; Bird, Liam; Mayes, Andrew; Arregui San Martín, Francisco Javier Upna (MDPI, 2017)   Artículo / Artikulua  OpenAccess
      Graphene and its derivatives have become the most explored materials since Novoselov and Geim (Nobel Prize winners for Physics in 2010) achieved its isolation in 2004. The exceptional properties of graphene have attracted ...
    • Optimization in nanocoated D-shaped optical fiber sensors 

      Del Villar, Ignacio Upna; Zubiate Orzanco, Pablo Upna; Ruiz Zamarreño, Carlos Upna; Arregui San Martín, Francisco Javier Upna; Matías Maestro, Ignacio Upna (Optical Society of America, 2017)   Artículo / Artikulua  OpenAccess
      Nanocoated D-shaped optical fibers have been proven as effective sensors. Here, we show that the full width at half minimum (FWHM) of lossy mode resonance can be reduced by optimizing the nanocoating width, thickness and ...
    • Optimized strain long-period fiber grating (LPFG) sensors operating at the dispersion turning point 

      Del Villar, Ignacio Upna; Fuentes, Omar; Chiavaioli, Francesco; Corres Sanz, Jesús María Upna; Matías Maestro, Ignacio Upna (IEEE, 2018)   Artículo / Artikulua  OpenAccess
      Two phenomena for enhancing the sensitivity of longperiod fiber gratings are combined toward an increase of the sensitivity to strain of this type of devices: the dispersion turning point (DTP) and the cladding diameter ...
    • Orness measurements for lattice m-dimensional interval-valued OWA operators 

      Miguel Turullols, Laura de Upna; Paternain Dallo, Daniel Upna; Lizasoain Iriso, María Inmaculada Upna; Ochoa Lezaun, Gustavo Upna; Bustince Sola, Humberto Upna (Elsevier, 2018)   Artículo / Artikulua
      Ordered weighted average (OWA) operators are commonly used to aggregate information in multiple situations, such as decision making problems or image processing tasks. The great variety of weights that can be chosen to ...
    • Parameter-independent control for battery chargers based on virtual impedance emulation 

      Urtasun Erburu, Andoni Upna; Berrueta Irigoyen, Alberto; Sanchis Gúrpide, Pablo Upna; Marroyo Palomo, Luis Upna (IEEE, 2018)   Artículo / Artikulua  OpenAccess
      An effective battery voltage regulation is fundamental to extend battery lifetime and to avoid overvoltage. However, the design of this regulation is complicated due to the wide battery impedance range, which, when dealing ...
    • Performance analysis of ZigBee wireless networks for AAL through hybrid ray launching and collaborative filtering 

      López Iturri, Peio Upna; Casino, Fran; Aguirre Gallego, Erik Upna; Azpilicueta Fernández de las Heras, Leyre Upna; Falcone Lanas, Francisco Javier Upna; Solanas, Agusti (Hindawi, 2016)   Artículo / Artikulua  OpenAccess
      This paper presents a novel hybrid simulation method based on the combination of an in-house developed 3D ray launching algorithm and a collaborative filtering (CF) technique, which will be used to analyze the performance ...
    • Phase reversal technique applied to fishnet metalenses 

      Pacheco-Peña, Víctor Upna; Minin, Igor V.; Minin, Oleg V.; Beruete Díaz, Miguel Upna (Hindawi, 2018)   Artículo / Artikulua  OpenAccess
      In this work, the fishnet metamaterial is applied to several converging metalenses by combining the zoning, reference phase, and phase reversal techniques. First, the zoning and reference phase techniques are implemented ...
    • Photonic nanojets with mesoscale high-index dielectric particles 

      Pacheco-Peña, Víctor Upna; Beruete Díaz, Miguel Upna (AIP Publishing, 2019)   Artículo / Artikulua  OpenAccess
      In this work, we demonstrate the ability of high-index dielectric particles immersed in air to generate photonic nanojets with extreme resolution (∼0.06λ0). Both 2D (cylindrical) and 3D (spherical) particles are analyzed, ...
    • Pulse coding linearization for Brillouin optical time-domain analysis sensors 

      Mariñelarena Ollacarizqueta, Jon Upna; Iribas Pardo, Haritz Upna; Loayssa Lara, Alayn Upna (Optical Society of America, 2018)   Artículo / Artikulua  OpenAccess
      We introduce a simple method to extend the performance of pulse coding techniques in their application to Brillouin optical time-domain analysis sensors (BOTDA). It is based on applying a simple logarithmic processing on ...
    • Ransomware early detection by the analysis of file sharing traffic 

      Morató Osés, Daniel Upna; Berrueta Irigoyen, Eduardo; Magaña Lizarrondo, Eduardo Upna; Izal Azcárate, Mikel Upna (Elsevier, 2018)   Artículo / Artikulua  OpenAccess
      Crypto ransomware is a type of malware that locks access to user files by encrypting them and demands a ransom in order to obtain the decryption key. This type of malware has become a serious threat for most enterprises. ...
    • Real time measuring system of multiple chemical parameters using microstructured optical fibers based sensors 

      López Aldaba, Aitor Upna; López Torres, Diego Upna; Elosúa Aguado, César Upna; Arregui San Martín, Francisco Javier Upna; Auguste, Jean-Louis; Jamier, Raphael; Roy, Philippe; López-Amo Sáinz, Manuel Upna (IEEE, 2018)   Artículo / Artikulua  OpenAccess
      In this paper, a multiplexing system for simultaneous interrogation of optical fiber sensors which measure different parameters is presented and validated. The whole system has been tested with 6 different sensing heads ...
    • Recent developments in fiber optics humidity sensors 

      Ascorbe Muruzabal, Joaquín Upna; Corres Sanz, Jesús María Upna; Arregui San Martín, Francisco Javier Upna; Matías Maestro, Ignacio Upna (MDPI, 2017)   Artículo / Artikulua  OpenAccess
      A wide range of applications such as health, human comfort, agriculture, food processing and storage, and electronic manufacturing, among others, require fast and accurate measurement of humidity. Sensors based on optical ...
    • Remote access protocols for Desktop-as-a-Service solutions 

      Magaña Lizarrondo, Eduardo Upna; Sesma Gracia, Iris; Morató Osés, Daniel Upna; Izal Azcárate, Mikel Upna (Public Library of Science, 2019)   Artículo / Artikulua  OpenAccess
      The use of remote desktop services on virtualized machines is a general trend to reduce the cost of desktop seats. Instead of assigning a physical machine with its operating system and software to each user, it is considerably ...
    • Response of complementary split ring resonators in composite stratified substrate integrated waveguide 

      Pérez Escudero, José Manuel Upna; Jarauta Ayensa, Eduardo Upna; Falcone Lanas, Francisco Javier Upna; Beruete Díaz, Miguel Upna (American Institute of Physics, 2017)   Artículo / Artikulua  OpenAccess
      In this work, the behavior of a Complementary Split Ring Resonator (CSRR) operating within the quasi-static resonance regime and embedded in a composite stratified Substrate Integrated Waveguide (SIW) with two different ...