Now showing items 21-40 of 2376

    • 3D electron density estimation in the ionosphere 

      Tuna, Hakan; Arıkan, Orhan; Arıkan, F. (IEEE, 2014)
      Ionosphere has ion distribution which is variable in space and time. There have been physical and empirical studies for modeling the ionosphere. International Reference Ionosphere extended to Plasmasphere (IRI-Plas) is the ...
    • 3D forest fire propagation simulation 

      Köse, Kıvanç; Grammalidis, N.; Yılmaz, E.; Çetin, A. Enis (IEEE, 2008-05)
      The increase in the number of forest fires in the last few years dispatch governments to take precautions. Besides prevention, early intervention is also very important in fire fighting. If the firefighters know where the ...
    • 3D human pose search using oriented cylinders 

      Pehlivan, Selen; Duygulu, Pınar (IEEE, 2009-09-10)
      In this study, we present a representation based on a new 3D search technique for volumetric human poses which is then used to recognize actions in three dimensional video sequences. We generate a set of cylinder like 3D ...
    • 3D Labyrinthine-type acoustical metamaterial proposals for sound control in architectural applications 

      Yazıcı, Beyza; Gül, Zühre Sü (Institute of Noise Control Engineering(INCE), 2019-06)
      The purpose of this research is to develop alternative 3D labyrinthine-type acoustical metamaterials by utilizing 'space-coiling' for sound control in architectural applications. Acoustical metamaterials have a great ...
    • 3D modeling of on-chip acoustophoretic particle manipulation in a polymer microfluidic device 

      Çaǧatay, E.; Özer, M. B.; Çetin, Barbaros (Chemical and Biological Microsystems Society, 2016)
      This study focuses on understanding of the sensitivities of the acoustophoretic process on uncertainties/errors in the geometric properties of the chip material and the piezoelectric actuators. The sensitivity of the ...
    • 3D printed microfluidic reactor for high throuhput chitosan nanoparticle synthesis 

      Aşık, M. D.; Çetin, Barbaros; Kaplan, M.; Erdem, Yegan; Saǧlam, N. (Chemical and Biological Microsystems Society, 2016)
      The major bottleneck for the commercialization of nanoparticle related technologies is the mass production of the nanoparticles. One approach to overcome this bottleneck is use of microfluidic devices. In this paper, a 3D ...
    • 3D thumbnails for mobile media browser interface with autostereoscopic displays 

      Gündoğdu, R. Bertan; Yiğit, Yeliz; Çapin, Tolga (Springer, 2010-01)
      In this paper, we focus on the problem of how to visualize and browse 3D videos and 3D images in a media browser application, running on a 3D-enabled mobile device with an autostereoscopic display. We propose a 3D thumbnail ...
    • 4,8 T/m manyetik parçacık görüntüleme tarayıcı tasarımı ve yapımı 

      Ütkür, Mustafa; Muslu, Yavuz; Sarıtaş, Emine Ülkü (IEEE, 2018)
      Manyetik Parçacık Görüntüleme (MPG), ilk yayımlandığı 2005 yılından bu yana hızla gelişerek anjiyografi, kök hücre takibi ve kanser görüntüleme gibi uygulama alanlarında ciddi ilerlemeler kaydetmiştir. İyonlaştırıcı ışıma ...
    • 45 GHz bandwidth-efficiency resonant cavity enhanced ITO-Schottky photodiodes 

      Bıyıklı, Necmi; Kimukin, İbrahim; Aytür, Orhan; Özbay, Ekmel; Gökkavas, M.; Ünlü, M. S. (OSA, 2001)
      We demonstrated high-performance resonant cavity enhanced ITO-Schottky photodiodes. We achieved a peak efficiency of 75% around 820 nm with a 3-dB bandwidth of 60 GHz resulting in a bandwidth-efficiency product of 45 GHz.
    • 50-W, 1.6-GHz pulse repetition rate from a burst-mode Yb-doped fiber laser 

      Elahi, Parviz; Ertek, A. C.; Eken, K.; İlday, Fatih Ömer (IEEE, 2017)
      We report a 50-W average power Yb-doped fiber laser amplifier system. The laser system produces bursts at a minimum rate of 200 kHz, with 1.6 GHz intraburst repetition rate. The total energy delivers in a burst is 250 μJ ...
    • A 6-18 GHz GaN power amplifier MMIC with high gain and high output power density 

      Sütbaş, Batuhan; Özipek, Ulaş; Gürdal, A.; Özbay, Ekmel (IEEE, 2019)
      A three-stage reactively-matched 6-18 GHz power amplifier MMIC design is presented. The design effort is focused on obtaining a low-loss output matching network for a high output power density. Active unit cells consist ...
    • A 60 GHz beam-steering reconfigurable antenna 

      Khalat, A.; Towfiq, Md. A.; Cetiner, B. A.; Ceylan, Ö.; Bıyıklı, Necmi (IEEE, 2016)
      We present the design, microfabrication, and characterization of a multifunctional reconfigurable antenna (MRA) with beam steering capability operating at 60 GHz band (59-66 GHz). The MRA provides 3 different beam directions ...
    • 83 W, 1 ns, 3.1 MHz all-fiber laser for micromachining 

      Özgören, Kıvanç; Öktem, Bülent; Yılmaz, Sinem; İlday, F. Ömer; Pasin, E.; Eken, K. (IEEE, 2011)
      Fiber lasers are commonly used for various material processing applications. The advantages (such as simplicity of the system, high material removal rate) and disadvantages (larger heat-affected zone, reduced precision) ...
    • 915 nm pumped 1018 nm Yb-doped all-fiber high power fiber laser system 

      Midilli, Yakup; Efunbajo, O. Benjamin; Şimşek, Bartu; Ortaç, Bülend (Institute of Electrical and Electronics Engineers Inc., 2019)
      Fibers lasers have attracted great attention in the last decades and the power scaling has reached tens of kW levels. Especially with the tandem pump configuration, pumping the active medium with a pump laser light instead ...
    • 94.8 km-range direct detection fiber optic distributed acoustic sensor 

      Uyar, Faruk; Uyar, Talha; Ünal, Canberk; Kartaloğlu, Tolga; Özdur, İbrahim; Özbay, Ekmel (Optical Society of America(OSA), 2019)
      This work demonstrates an ultra-long range direct detection fiber optic distributed acoustic sensor which can detect vibrations at a distance of 94.8 km with 10 m resolution along the sensing fiber.
    • ABC: a double-conversion compiler/solver for nanoscience calculus 

      Kulik, Igor O. (Computational Publications, 2003)
      "CompLab" ("Compiler Laboratory") or "ABC" ("Advanced Basic-C") is a double conversion compiler working in two parallel regimes (A and B) one of which is similar to that of MATLAB while the other is a professional compilation ...
    • Ablation-cooled material removal at high speed with femtosecond pulse bursts 

      Kerse, Can; Kalaycıoğlu, Hamit; Elahi, Parviz; Akçaalan, Önder; Yavaş, S.; Aşık, M. D.; Kesim, Deniz Koray; Yavuz, Koray; Çetin, Barbaros; İlday, Fatih Ömer (OSA, 2015)
      We report exploitation of ablation cooling, a concept well-known in rocket design, to remove materials, including metals, silicon, hard and soft tissue. Exciting possibilities include ablation using sub-microjoule pulses ...
    • About the Wigner distribution of a graded index medium and the fractional fourier transform operation 

      Özaktaş, Haldun M.; Mendlovic, D.; Lohmann, A. W. (SPIE, 1993-08)
      Upon propagation through quadratic graded index media, the Wigner distribution of the wavefunction of light rotates uniformly. As a consequence, a definition of fractional Fourier transforms based on rotating the functions ...
    • Accuracy and efficiency considerations in the solution of extremely large electromagnetics problems 

      Gürel, Levent; Ergül, O. (IEEE, 2011)
      This study considers fast and accurate solutions of extremely large electromagnetics problems. Surface formulations of large-scale objects lead to dense matrix equations involving millions of unknowns. Thanks to recent ...