Now showing items 21-40 of 320

    • Assessment of Wireless Sensor Network Lifetime Reduction due to Elimination of Critical Node Sets 

      Yildiz, Huseyin Ugur; Tavlı, Bülent; Kahjogh, Behnam Ojaghi (IEEE, 2017)
      Wireless Sensor Networks (WSN) are used in various critical monitoring applications such as military safety, environmental surveillance, etc. In such scenarios, it is common that WSN nodes are threatened by potential ...
    • Asymmetric light transmission by using 2D PT-symmetric photonic nanostructure 

      Turduev, M.; Botey, M.; Herrero, R.; Giden, I.; Kurt, Hamza; Staliunas, K. (Institute of Electrical and Electronics Engineers Inc., 2014-12)
      We propose for the first time a simple realization of a two-dimensional Parity-Time symmetric hexagonal shaped photonic structure composed of honeycomb lattice. The structure has a symmetric periodic modulation of the ...
    • Asymmetric light transmission effect based on an evolutionary optimized semi-Dirac cone dispersion photonic structure 

      Bor, E.; Turduev, M.; Yasa, U.G.; Kurt, Hamza; Staliunas, K. (American Physical Society, 2018-12-10)
      In this paper, we present the numerical and experimental demonstration of asymmetric light transmission by a compact photonic crystal (PC) structure, which sustains semi-Dirac cone dispersion. The semi-Dirac point is ...
    • Asymmetric Light Transmission in PT-Symmetric Microring Resonators 

      Giden, Ibrahim Halil; Dadashi, Khalil; Botey, Muriel; Herrero, Ramon; Staliunas, Kestutis; Kurt, Hamza (IEEE-Inst Electrical Electronics Engineers Inc, 2016)
      We propose a new type of add-drop microring resonator made of gain and loss materials. Microring resonators are compact, narrow band, and optical channel dropping filters. In such linear systems, light transmission to ...
    • Asymmetric transmission from a 2D PT-symmetric honeycomb nanostructure 

      Botey, M.; Herrero, R.; Turduev, M.; Zhao, D.; Giden, I.; Kurt, Hamza; Staliunas, K. (IEEE Computer Society, 2014)
      We propose a simple realization of a 2-dimensonal (2D) PT-symmetric photonic structure: a honeycomb arrangement of alternating cylinders with gain or loss in a dielectric background. The structure provides a periodic ...
    • Autonomous Face Detection and Tracking Using Quadrotor UAV 

      Karahan, M.; Kurt, Hamza; Kasnakoğlu, Coşku (Institute of Electrical and Electronics Engineers Inc., 2020-10)
      In this paper, human face detection and tracking system with a camera of the Quadrotor UAV is proposed. During flight, Quadrotor takes photos of the human face, records videos and sends these photos and videos to the ...
    • Autonomous Navigation of an Aircraft Using a NARX Recurrent Neural Network 

      Sezginer, K.; Kasnakoğlu, Coşku (Institute of Electrical and Electronics Engineers Inc., 2019-11)
      This paper explores autonomous aircraft navigation using machine learning approach focusing on the ground run and takeoff which is one of the most critical control problems in the aircraft navigation. A controller which ...
    • Backhaul-Aware Optimization of UAV Base Station Location and Bandwidth Allocation for Profit Maximization 

      Cicek, Cihan Tugrul; Gültekin, Hakan; Tavlı, Bülent; Yanikomeroglu, Halim (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2020)
      Unmanned Aerial Vehicle Base Stations (UAV-BSs) are envisioned to be an integral component of the next generation Wireless Communications Networks (WCNs) with a potential to create opportunities for enhancing the capacity ...
    • Backward propagation of surface slow light in photonic crystals through morphological diversity 

      Yeltik, Aydan; Yilmaz, Done; Kurt, Hamza (SPIE, 2018-04)
      We propose and demonstrate photonic crystals (PCs) providing backward-directional propagation of surface slow waves, which is significant for potential PC-based photonic applications. An effective pathway for backward ...
    • Biosensing With Asymmetric High Refractive Index Contrast Gratings 

      Erim, Nur; Erim, Muhammed Necip; Yilmaz, Done; Kurt, Hamza (IEEE-Inst Electrical Electronics Engineers Inc, 2016-10-15)
      We propose a novel label-free optical biosensor configuration based on a spectral refractive index sensing method by utilizing asymmetric high index contrast dielectric gratings. The characterization and performance ...
    • Broadband and polarization-independent asymmetric transmission of visible light through a three-dimensional trapezoidal metallic metasurface 

      Özer, Ahmet; Koçer, Hasan Erdinç; Kurt, Hamza (OSA - The Optical Society, 2018-09-01)
      In modern optical applications, it has become an important need to flow light unidirectionally. An optical diode realizes this task as an electrical counterpart manipulates the flow of electrons in semiconductor materials. ...
    • Broadband asymmetric light transmission based on all-dielectric metasurfaces in the visible spectrum 

      Özer, Ahmet; Yılmaz, Nazmi; Koçer, Hasan; Kurt, Hamza (IOP PUBLISHING LTD, 2019-05)
      An asymmetric transmission device composed of all dielectric phase gradient metasurfaces on the dielectric substrate in the visible wavelengths is proposed and designed. In order to verify its operation principle and ...
    • Broadband direction-dependent transmission of light with photonic crystal heterostructure grating 

      Yılmaz, Döne; Giden, İbrahim Halil; Kurt, Hamza (IOP Publishing Ltd., 2018-01-17)
      Direction-dependent light transmission is a remarkable phenomenon owing to its great potential to be used in optical communication processing systems such as optical diodes, isolators and rectifiers. All these applications ...
    • Broadband directional cloaking using graded index structures 

      Oner, B.B.; Can, M.G.; Kurt, Hamza (IEEE Computer Society, 2014)
      We propose broadband two-dimensional cloaking designs based on isotropic and all dielectric lossless materials. The photonic structures are created by implementing artificially generated graded index (GRIN) media. The ...
    • Broadband one way propagation via dielectric waveguides with unequal effective index 

      Öner, B.B.; Üstün, K.; Kurt, H.; Okyay, A.K.; Turhan-Sayan, G. (Institute of Electrical and Electronics Engineers Inc., 2014-12)
      We present an efficient approach for broad band one way propagation of light by parallel and unequal dielectric waveguides leading different effective phase shifts. Three dimensional numerical simulations show that 30% ...
    • A broadband polarization-insensitive diffractive lens design for subwavelength focusing of light 

      Yıldırım, Bumin K.; Bor, Emre; Kurt, Hamza; Turduev, Mirbek (IEEE Computer Society, 2019)
      In this study, we propose the metaheuristic design of a polarization-insensitive diffractive lens. The designed lens structure consists of concentric dielectric rings with optimally modulated widths and heights. Here, the ...
    • Broadband self-collimation in C2 symmetric photonic crystals 

      Gümüş, Melike; Giden, İbrahim Halil; Kurt, Hamza (OSA - The Optical Society, 2018-06-01)
      In this study, we report a low-symmetric photonic crystal (PhC) structure that exhibits high coupling efficiency in a broadband frequency range with a tilted self-collimating capability. First, the analytical approach is ...
    • Chiral modes in 2D PT-symmetric nanostructures 

      Botey, M.; Herrero, R.; Turduev, M.; Giden, I.; Kurt, Hamza; Staliunas, K. (Springer Science and Business Media, LLC, 2016)
      We propose a 2-dimensonal PT-symmetric photonic honeycomb structure that supports chiral Block-likemodes being its excitation input and frequency dependent. We show that while the fundamental resonant frequency excites the ...
    • Classification of Electronic Devices With Power-Swept Signals Using Harmonic Radar 

      Hayvacı, Harun Taha; Ilbegi, Handan; Yetik, Imam Şamil (Institute of Electrical and Electronics Engineers Inc., 2020-06)
      A novel approach for classification of electronic devices using a harmonic radar is proposed in this article. We transmit single-tone time-varying signals with varying power to the electronic circuits under test (ECUTs). ...
    • Clustering-based device-to-device cache placement 

      Kazez, Ahmet Cihat; Girici, Tolga (Elsevier B.V., 2019)
      In this work we consider the problem of optimal cache placement in a D2D enabled cellular network. There are a number of helper devices in the area, which use their cached contents to help other users and offload traffic ...