Now showing items 1-20 of 295

    • 3D imaging for ground-penetrating radars via dictionarydimension reduction 

      Duman, Muhammed; Gürbüz, Ali Cafer (TÜBİTAK, 2015)
      Ground-penetrating radar (GPR) has been widely used in detecting or imaging subsurface targets. In many applications such as archaeology, utility imaging, or landmine detection, three-dimensional (3D) images of the subsurface ...
    • Accelerating beam generation via all-dielectric metasurfaces 

      Yılmaz, Nazmi; Bağcı, Fehim Taha; Özer, Ahmet; Kurt, Hamza (SPIE, 2019)
      All-dielectric metasurfaces are unique component to control optical wavefront with high transmission or reflection coefficient. Recently, accelerating beam, which propagates along curved arbitrary trajectories, has been ...
    • Active beam steering and afocal zooming by nematic liquid crystal-infiltrated graded index photonic structures 

      Babayigit, Ceren; Kurt, Hamza; Turduev, Mirbek (Institute of Physics Publishing, 2019)
      This study presents active beam steering and afocal zooming of light by incorporating liquid crystals (LCs) with graded index photonic crystals (GRIN PCs). The GRIN PC structures are composed of low refractive index polymer ...
    • Active Fault Detection in Linear Controller Hardware with Sine Signal 

      Ozkan, M.; Kasnakoğlu, Coşku (Institute of Electrical and Electronics Engineers Inc., 2020-04)
      In this paper, active fault detection is used to detect hardware failure in Linear Controller. Auxiliary test signal is chosen as sine signal. Then frequency and magnitude of sine signal is designed according to bode plot ...
    • Adaptive detection with diffuse multipath exploitation in partially homogeneous environments 

      Hayvacı, Harun Taha; Gülen, Seden Hazal ( Institute of Electrical and Electronics Engineers Inc., 2019)
      In this paper, we deal with the problem of detecting point-like targets in the presence of multipath under the assumption of a partially homogeneous Gaussian disturbance with unknown covariance matrix. Therefore, we introduce ...
    • Adaptive Graded Index Photonic Crystal Lens Design via Nematic Liquid Crystals 

      Giden, Ibrahim Halil; Eti, Neslihan; Rezaei, Behrooz; Kurt, Hamza (IEEE-Inst Electrical Electronics Engineers Inc, 2016-10)
      An adaptive graded index photonic crystal (GRIN PC) lens system is designed by using liquid crystal (LC) infiltration. LCs have the property to change their refractive indices when an external voltage is applied. This ...
    • Adaptive Model Predictive Control of a Two-wheeled Robot Manipulator with Varying Mass 

      Önkol, M.; Kasnakoğlu, Coşku (SAGE Publications Ltd, 2018-03)
      This paper presents the adaptive model predictive control approach for a two-wheeled robot manipulator with varying mass. The mass variation corresponds to the robot picking and placing objects or loads from one place to ...
    • Adaptive modulation for completion time minimization in wireless broadcast networks 

      Yüksel, Melda; Genc, Yasin (Elsevier Gmbh, Urban & Fischer Verlag, 2017)
      In this work we study the effect of hierarchical modulation on completion time minimization in wireless broadcast channels. Time needed to transmit all bits intended for a particular user is defined as its completion time. ...
    • Advances in Capacitive Micromachined Ultrasonic Transducers 

      Brenner, Kevin; Ergun, Arif Şanlı; Firouzi, Kamyar; Rasmussen, Morten Fischer; Stedman, Quintin; Khuri-Yakub, Butrus (Pierre) (MDPI, 2019-02)
      Capacitive micromachined ultrasonic transducer (CMUT) technology has enjoyed rapid development in the last decade. Advancements both in fabrication and integration, coupled with improved modelling, has enabled CMUTs to ...
    • Aileron Locking Fault Detection Based on Extended Kalman Filter for UAV 

      Demircan, M.; Kasnakoğlu, Coşku (Association for Computing Machinery, 2019-08)
      This paper presents application of Nonlinear Extended Kalman Filter for aileron actuator locking scenario in Unmanned Aerial Vehicles and estimation of states to make comparison between sensor results and estimation results. ...
    • All-dielectric metasurface lenses for focal plane arrays operating in mid-wave infrared spectrum 

      Yilmaz, Nazmi; Ozdemir, Aytekin; Bagci, Fehim T.; Takashima, Yuzuru; Kurt, Hamza (SPIE, 2018-08)
      Focal plane arrays (FPAs) as a two-dimensional detector pixel matrix positioned in the focal plane of an optical system have been developed continuously for obtaining higher resolution. On the other hand, for developing ...
    • All-Dielectric Self-Cloaked Structures 

      Hayran, Zeki; Kurt, Hamza; Herrero, Ramon; Botey, Muriel M.; Staliunas, K. (American Chemical Society, 2018-05-16)
      A general procedure to design objects that are intrinsically invisible (without the necessity of an external cloak) has not been demonstrated so far. Here we propose a flexible method to design such self-cloaked objects ...
    • Altitude Control for Small Fixed-Wing Aircraft Using H-infinity Loop-Shaping Method 

      Akyurek, Seyma; Kaynak, Unver; Kasnakoğlu, Coşku (Elsevier Science BV, 2016)
      Autopilot systems for UAVs without human pilots maintain the flight through an appropriate balance of aerodynamic forces autonomously. That is to say, they arc used to make flight missions more reliable and efficient. ...
    • The Analysis of RCS of Winged Almond Model with Ammunition and without Ammunition 

      Durlu, Caglayan; Hayvacı, Harun Taha (IEEE, 2017)
      In this paper, the design, analysis and numerical results of back scattering field of winged almond model with ammunition and without ammunition are presented. Simulations with using Physical Optics (PO) method in Ansys ...
    • Analysis of the focusing crosstalk effects of broadband all-dielectric planar metasurface microlens arrays for ultra-compact optical device applications 

      Ozdemir, Aytekin; Yilmaz, Nazmi; Alboon, Shadi A.; Takashima, Yuzuru; Kurt, Hamza (Optical Soc Amer, 2018-10-15)
      Microlens arrays have been widely used for different optoelectronic applications. The demand for compact optical devices necessitates the deployment of even smaller microlens arrays; however, as the spacing between individual ...
    • Analysis of the Tradeoff Between Network Lifetime and k-connectivity in WSNs 

      Cobanlar, Muhammed; Akram, Vahid Khalilpour; Dagdeviren, Orhan; Tavlı, Bülent (IEEE, 2018)
      Reliability and network lifetime maximization are two important objectives when designing a Wireless Sensor Network (WSN). However, these two are conflicting objectives. To increase the reliability maintaining k-connectivity ...
    • Analytical, numerical, and experimental investigation of a Luneburg lens system for directional cloaking 

      Babayiğit, Ceren; Evren, Aydın S.; Bor, Emre; Kurt, Hamza; Turduev, Mirbek (American Physical Society, 2019)
      In this study, the design of a directional cloaking based on the Luneburg lens system is proposed and its operating principle is experimentally verified. The cloaking concept is analytically investigated via geometrical ...
    • Angular filtering by Bragg photonic microstructures fabricated by physical vapour deposition 

      Grineviciute, Lina; Babayigit, Ceren; Gailevicius, Darius; Bor, Emre; Turduev, Mirbek; Purlys, Vytautas; Tolenis, Tomas; Kurt, Hamza; Staliunas, Kestutis ( Elsevier B.V., 2019)
      We propose and experimentally demonstrate spatial filtering by photonic crystals in a Bragg configuration. Compared to the Laue configuration, where spatial filtering was already demonstrated before, the Bragg configuration ...
    • Approximate Fourier Domain Expression for Bloch-Siegert Shift 

      Turk, Esra Abaci; Ider, Yusuf Ziya; Ergün, Arif Şanlı; Atalar, Ergin (Wiley-Blackwell, 2015-01)
      PurposeIn this study, a new simple Fourier domain-based analytical expression for the Bloch-Siegert (BS) shift-based B-1 mapping method is proposed to obtain vertical bar b(1)(+)vertical bar more accurately while using ...
    • 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 ...