Now showing items 1-20 of 25

    • Accurate positioning in ultra-wideband systems 

      Soganci, H.; Gezici, S. (Institute of Electrical and Electronics Engineers, 2011)
      Accurate positioning systems can be realized via ultra-wideband signals due to their high time resolution. In this article, position estimation is studied for UWB systems. After a brief introduction to UWB signals and their ...
    • Autonomous navigation of robotic units in mobile sensor network 

      Nazlibilek, S. (2012)
      This work is motivated by the problem of detecting buried anti-tank and anti-personnel mines in roads or some border regions. The problem is tried to be solved by use of small mobile robotic sensors and their some abilities ...
    • Bistable behavior of a two-mode Bose-Einstein condensate in an optical cavity 

      Safaei, S.; Mustecaplioglu, Ö. E.; Tanatar, B. (IOP Institute of Physics Publishing, 2013-01-11)
      We consider a two-component Bose-Einstein condensate in a one-dimensional optical cavity. Specifically, the condensate atoms are taken to be in two degenerate modes due to their internal hyperfine spin degrees of freedom ...
    • Comparative analysis of different approaches to target classification and localization with sonar 

      Ayrulu, B.; Barshan, B. (2001)
      The comparison of different classification and fusion techniques was done for target classification and localization with sonar. Target localization performance of artificial neural networks (ANN) was found to be better ...
    • Cooperative positioning in wireless networks 

      Gholami, M. R.; Keskin, M. F.; Gezici, Sinan; Jansson, M. (John Wiley & Sons, 2016)
      In this article, we study cooperative positioning in wireless networks in which target nodes at unknown locations locally collaborate with each other to find their locations. We review different models available for ...
    • Coupled optical microcavities in one-dimensional photonic bandgap structures 

      Bayindir, M.; Kural, C.; Ozbay, E. (Institute of Physics Publishing, 2001)
      We present a detailed theoretical and experimental study of the evanescent coupled optical microcavity modes in one-dimensional photonic bandgap structures. The coupled-cavity samples are fabricated by depositing alternating ...
    • Enhanced coupling to microsphere resonances with optical fibers 

      Serpengüzel, A.; Arnold, S.; Griffel, G.; Lock, J. A. (Optical Society of America, 1997)
      Morphology-dependent resonances (MDR's) of polystyrene microspheres were excited by an optical fiber coupler. For optical elimination of the air-cladding interface at the optical fiber coupler surface, the microsphere was ...
    • Fabrication, characterization and simulation of plasmonic cavities 

      Karabıyık, Mustafa (Bilkent University, 2010)
      Surface plasmon polaritons (SPPs) originate from the collective oscillations of conduction electrons coupled with photons propagating at metal-dielectric interfaces. A uniform metallic gratings change the dispersion ...
    • Grating based plasmonic cavities 

      Şenlik, Servet Seçkin (Bilkent University, 2009)
      Surface plasmon polaritons are dipole carrying electromagnetic excitations occur- ing at metal-dielectric interfaces. Metallic periodic structures exhibit modi¯ed transmission and re°ection spectra owing to the interaction ...
    • An inquiry into the metrics for evaluation of localization algorithms in wireless ad hoc and sensor networks 

      Aksu, Hidayet (Bilkent University, 2008)
      In ad-hoc and sensor networks, the location of a sensor node making an observation is a vital piece of information to allow accurate data analysis. GPS is an established technology to enable precise position information. ...
    • Investigation of localized coupled-cavity modes in two-dimensional photonic bandgap structures 

      Ozbay, E.; Bayindir, M.; Bulu, I.; Cubukcu, E. (IEEE, 2002)
      We present a detailed study of the localized coupled-cavity modes in 2-D dielectric photonic crystals. The transmission, phase, and delay time characteristics of the various coupled-cavity structures are measured and ...
    • Jammer placement algorithms for wireless localization systems 

      Kurt, Mehmet Necip (Bilkent University, 2016-07)
      The optimal jammer placement problem is proposed and analyzed for wireless localization systems. In particular, the optimal location of a jammer node is obtained by maximizing the minimum of the Cram´er-Rao lower bounds ...
    • Jamming of Wireless Localization Systems 

      Gezici, S.; Gholami, M. R.; Bayram, S.; Jansson M. (Institute of Electrical and Electronics Engineers Inc., 2016)
      In this paper, the optimal jamming of wireless localization systems is investigated. Two optimal power allocation schemes are proposed for jammer nodes in the presence of total and peak power constraints. In the first ...
    • Line segment based range scan matching without pose information for indoor environments 

      Yakın, İskender (Bilkent University, 2008)
      A mobile robot exploring an unknown environment often needs to keep track of its pose through its sensors. Range scan matching is a way of computing the pose difference of a robot at two different locations on the ...
    • Localization and Tracking of Implantable Biomedical Sensors 

      Umay, I.; Fidan, B.; Barshan, B. (MDPI AG, 2017)
      Implantable sensor systems are effective tools for biomedical diagnosis, visualization and treatment of various health conditions, attracting the interest of researchers, as well as healthcare practitioners. These systems ...
    • Localization via visible light systems 

      Keskin, M. F.; Sezer, A. D.; Gezici, S. (Institute of Electrical and Electronics Engineers, 2018)
      Visible light communication (VLC) is an emerging paradigm that enables multiple functionalities to be accomplished concurrently, including illumination, high-speed data communications, and localization. Based on the VLC ...
    • Observation of cavity structures in composite metamaterials 

      Caglayan, H.; Ozbay, E. (S P I E - International Society for Optical Engineering, 2010-07-29)
      We investigated the cavity structure by the deformation of a unit cell of a Composite Metamaterial (CMM) structure. We considered different cavity structures with different resonance frequencies and Q-factors. We observed ...
    • Optimal jammer placement in wireless localization networks 

      Gezici, S.; Bayram, S.; Gholami, M. R.; Jansson, M. (Institute of Electrical and Electronics Engineers Inc., 2015)
      The optimal jammer placement problem is proposed for a wireless localization network, where the aim is to degrade the accuracy of locating target nodes as much as possible. In particular, the optimal location of a jammer ...
    • Optimal jammer placement in wireless localization systems 

      Gezici, S.; Bayram, S.; Kurt, M. N.; Gholami, M. R. (Institute of Electrical and Electronics Engineers Inc., 2016)
      In this study, the optimal jammer placement problem is proposed and analyzed for wireless localization systems. In particular, the optimal location of a jammer node is obtained by maximizing the minimum of the Cramér-Rao ...
    • Optimal jamming of wireless localization systems 

      Gezici, S.; Gholami, M.R.; Bayram, S.; Jansson, M. (Institute of Electrical and Electronics Engineers Inc., 2015)
      In this study, optimal jamming of wireless localization systems is investigated. Two optimal power allocation schemes are proposed for jammer nodes in the presence of total and peak power constraints. In the first scheme, ...