Now showing items 634-653 of 678

    • Ultimate intrinsic SNR in magnetic resonance imaging by optimizing the EM field generated by internal coils 

      Abdel-Hafez, Imad Amin (Bilkent University, 2000)
      A method to find the ultimate intrinsic signal-to-noise ratio (ISNR) in a magnetic resonance imaging experiment is applied to a human body model. The method uses cylindrical wave expansion to represent an arbitrary ...
    • Ultra low noise fiber optic acoustic sensor for underwater applications 

      Bilek, Şaban (Bilkent University, 2015-08)
      Fiber optic sensor have many advantages over the conventional sensor technologies such as electromangnetic compatibility, light weight, exible geometric design, sensing signal at a remote point and no electrical signal ...
    • Ultra wideband tapered power combiner/divider 

      Ünlü, Okan (Bilkent University, 2014)
      Many typologies like the designs of Wilkinson Power Divider and Gysel Power Divider have been worked and improved through the years. Each design targets a higher bandwidth, a better isolation and a higher power handling ...
    • Ultra-low-cost broad-band near-infrared silicon photodetectors based on hot electrons 

      Nazirzadeh, Mohammad Amin (Bilkent University, 2015)
      Silicon is at the heart of all of the end-user digital devices such as smart phones, laptops, and wearable technologies. It is the holy grail for the largescale production of semiconductor devices since start of the ...
    • Ultraviolet-visible nanophotonic devices 

      Bütün, Bayram (Bilkent University, 2010)
      Recently in semiconductor market, III-Nitride materials and devices are of much interest due to their mechanical strength, radiation resistance, working in the spectrum from visible down to the deep ultraviolet region ...
    • Uncertain linear equations 

      Pilancı, Mert (Bilkent University, 2010)
      In this thesis, new theoretical and practical results on linear equations with various types of uncertainties and their applications are presented. In the first part, the case in which there are more equations than unknowns ...
    • Underwater acoustic modem using OFDM 

      Yüksel, Mine Merve (Bilkent University, 2012)
      This thesis is about design, simulation and testing of an underwater acoustic modem using OFDM. The thesis work combines a theoretical part, whose objective is to understand the appropriate techniques to deal with the ...
    • A unification and comparison of the methods of construction for decentralized stabilizing controllers 

      Koçan, Ali Aydın (Bilkent University, 1993)
      In this thesis, the construction and characterization methods that use stable proper fractional representation for the solution of decentralized stabilization problem is presented in a unified manner. Four methods of ...
    • Unraveling excitonic dynamics of solution-processed quantum well stacks 

      Erdem, Onur (Bilkent University, 2015-08)
      Colloidal semiconductor quantum wells, also commonly known as nanoplatelets (NPLs), are a new class of atomically at nanocrystals that are quasi twodimensional in lateral size with vertical thickness control in atomic ...
    • Uplink scheduling algorithms for the rtPS traffic class for IEEE 80216 networks 

      Ertürk, Mustafa Cenk (Bilkent University, 2008)
      IEEE 802.16 MAC provides extensive bandwidth allocation and QoS mechanisms for various types of applications. However, the scheduling mechanisms for the uplink and downlink are unspecified by the IEEE 802.16 standard ...
    • Uplink scheduling for delay sensitive traffic in broadband wireless networks 

      Coşkun, Cemil Can (Bilkent University, 2012)
      In wireless networks, there are two main scheduling problems: uplink (mobile station to base station) and downlink (base station to mobile station). During the downlink scheduling, scheduler at the base station (BS) has ...
    • Use of dropouts and sparsity for regularization of autoencoders in deep neural networks 

      Ali, Muhaddisa Barat (Bilkent University, 2015-01)
      Deep learning has emerged as an e ective pre-training technique for neural networks with many hidden layers. To overcome the over- tting issue, usually large capacity models are used. In this thesis, two methodologies ...
    • User grouping in wireless networks with full duplex base stations and legacy mobile stations 

      Ünal, Deniz (Bilkent University, 2018-08)
      Improving spectral efficiency is a key objective in next generation wireless networks. Recent advances in self-interference cancellation techniques made in-band full-duplex wireless communications possible. Unlike ...
    • Using reinforcement learning for dynamic link sharing problems under signaling constraints 

      Çelik, Nuri (Bilkent University, 2003)
      In static link sharing system, users are assigned a fixed bandwidth share of the link capacity irrespective of whether these users are active or not. On the other hand, dynamic link sharing refers to the process of ...
    • Using spread spectrum coded pings in active sonar technology 

      Kumru, Yasin (Bilkent University, 2014)
      Performance of coded signals in active Sound Navigation and Ranging (SONAR) technology is studied in this work. In this work, the possibility of having covertness and environment friendliness in SONAR systems is investigated. ...
    • Utilization of improved recursive-shortest-spanning-tree method for video object segmentation 

      Tuncel, Ertem (Bilkent University, 1997)
      Emerging standards MPEG-4 and MPEG-7 do not standardize the video object segmentation tools, although their performance depends on them. There are a lot of still image segmentation algorithms in the literature, like ...
    • V-BLAST/MAP : a new symbol detection algorithm for mimo channels 

      Yapıcı, Yavuz (Bilkent University, 2005)
      In this thesis, we introduce a new symbol detection algorithm for MIMO channels. This algorithm is an extension of the well-known V-BLAST algorithm. The new algorithm, V-BLAST/MAP, combines elements of the V-BLAST ...
    • The V-Groove lens 

      Bozkurt, Ayhan (Bilkent University, 1994)
      Primarily designed for imaging purposes, the acoustic microscope finds application in the qualitative evaluation of materials, too. The lens response as a function of defocus, which is known as the V{z) curve, is formed ...
    • Variable capacitor based mechanical energy-to-electrical energy converter 

      Aydoğdu, Elif (Bilkent University, 2007)
      Today miniature stand-alone systems highly benefit from the improvements in IC technology. Shrinking dimensions to submicron technologies and reduced power consumption in the order of nano-watts open possibilities for ...
    • Variations in associative memory design 

      Akar, Mehmet (Bilkent University, 1996)
      This thesis is concerned with the anaiysis and synthesis of neurai networks to be used as associative memories. First considering a discrete-time neurai network modei which uses a quantizer-type muitiievei activation ...