Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/11
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Conference Object Citation - Scopus: 2Compact Proton Accelerator in Uhf Band at Kahvelab(JACoW Publishing, 2022) Esen, S.; Adıgüzel, A.; Koçer, O.; Çağlar, A.; Çelebi, E.; Öz, S.; Özcan, V.E.; Karatay, Anıl; Yaman, Fatih; Yılmaz, Hasan ÖnderProton Test Beam at KAHVELab (Kandilli Detector, Accelerator and Instrumentation Laboratory) project aims to design and produce a radio frequency quadrupole (RFQ) operating at 800 MHz in Istanbul, Turkey using the local resources. The beamline consists of a proton source, a low energy beam transport (LEBT) line including the beam diagnostic section and the RFQ cavity itself. This RFQ is 4-vane, 1-meter-long cavity to accelerate the 20 keV beam extracted from plasma ion source to 2 MeV. Its engineering prototype is already produced and subjected to mechanical, low power RF and vacuum tests. In this study, the results of the first test production, especially the bead-pull test setup will be discussed. © 2022 Proceedings - Linear Accelerator Conference, LINAC. All rights reserved.Conference Object Citation - Scopus: 8Localization of a Passive Molecular Transmitter With a Sensor Network(Springer, 2020) Güleç, Fatih; Atakan, BarışMacroscale molecular communication (MC), which has a potential for practical applications, is a promising area for communication engineering. In a practical scenario such as monitoring air pollutants released from an unknown source, it is essential to estimate the location of the molecular transmitter (TX). This paper presents a novel Sensor Network-based Localization Algorithm (SNCLA) for passive transmission by using a novel experimental platform which mainly comprises a clustered sensor network (SN) with 24 sensor nodes and evaporating ethanol molecules as the passive TX. With the usage of the SN concept, novel methods can be developed for the problems in macroscale MC by utilizing the wide literature of sensor networks. In SNCLA, Gaussian plume model is employed to derive the location estimator. The parameters such as transmitted mass, wind velocity, detection time and actual concentration are calculated or estimated from the measured signals via the SN to be employed as the input for the location estimator. The numerical results show that the performance of SNCLA is better for stronger winds in the medium. Our findings show that evaporated molecules do not propagate homogeneously through the SN due to the presence of the wind. In addition, the estimation error of SNCLA decreases for higher detection threshold values. © 2020, ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering.Conference Object Citation - WoS: 14Citation - Scopus: 14An Overview of the Recent Advances in Fbg-Assisted Phase-Sensitive Otdr Technique and Its Applications(IEEE, 2020) Yüksel, Kıvılcım; Koçal, Ertunga Burak; Jason, Johan; Wuilpart, Marc; Sainz, Manuel Lopez-AmoIn this paper, we discuss the operation principles, sensing mechanism, challenges and application areas of FBG-assisted phase-sensitive optical time-domain reflectometry. A special emphasis is given to the interrogation of fiber Bragg grating arrays for vibration sensing application. Results obtained by different research groups are compared in terms of performance characteristics and future perspectives. Recent progress obtained through our research collaboration are also presented. In particular, the detrimental spectral shadowing effect and multiple reflection crosstalk are analysed and mitigation techniques are proposed. © 2020 IEEE.Conference Object Index Modulation of Transient Grating in Nonlinear Medium(SPIE, 2016) Karakılınç, Özgür Önder; Dinleyici, Mehmet SalihA transient chirped grating structure is formed by beam interferences in nonlinear photonic crystal waveguide. Pulse propagation in nonlinear transient grating media is investigated and its impact on the transmission dynamics is explored. The grating may not be stationary propagating but anharmonically oscillating. Thus, effective modification of the refractive index needs to be evaluated in detail.Conference Object Citation - Scopus: 1Fs Fbgs as Probes To Monitor Thermal Regeneration Mechanisms(SPIE, 2019) Chah, K.; Kinet, D.; Yüksel, Kıvılcım; Caucheteur, C.This paper shows that fiber Bragg gratings written in standard single mode optical fiber with IR femtosecond pulses and point-by-point technique are high temperature resistant (< 1000 degrees C). Moreover, after calibration process, these gratings can be used as a reference to study and discriminate between different high temperature annealing mechanisms involved in other types of gratings and/or fibers. Here we have considered the regeneration process of gratings written by UV laser in boron/germanium co-doped single mode optical fiber. Hence, the monitoring of grating strength and differential wavelength shift between femtosecond and type-I gratings during annealing cycle yields the wavelength shift due to the annealing of doping (mainly boron) and UV-related defects and their relative contributions to the regeneration mechanism.Conference Object Kahve Laboratory Rf Circulator and Transmission Line Project(American Institute of Physics, 2018) Çetinkaya, Hakan; Çağlar, Aslıhan; Çicek, Cihan; Özbey, Aydın; Sunar, Ezgi; Türemen, Görkem; Yıldız, Hüseyin; Yüncü, Alperen; Özcan, Erkcan; Ünel, Gökhan; Yaman, FatihAn 800 MHz RF circulator and transmission line project has recently started at the newly commissioned Kandilli Detector, Accelerator and Instrumentation (KAHVE) Laboratory at the Boǧaziçi University. The aims are to design, build and construct an RF circulator and transmission line in Turkey for high power and high frequency applications. The project consists of 8 transmission line elements: 800 MHz RF generator with 60 kW power (klystron), klystron to waveguide converter, waveguides, E and H bends, 3-port circulator and waveguide to coaxial converter to transmit RF power to a pillbox RF cavity. Design studies and details of the ongoing project will be presented.Conference Object Approximate Best Linear Unbiased Channel Estimation for Multi-Antenna Frequency Selective Channels With Applications To Digital Tv Systems(SPIE, 2004) Özen, Serdar; Pladdy, Christopher; Nerayanuru, Sreenivasa M.; Fimoff, Mark J.; Zoltowski, Michael D.We provide an iterative and a non-iterative channel impulse response (CIR) estimation algorithm for communication receivers with multiple-antenna. Our algorithm is best suited for communication systems which utilize a periodically transmitted training sequence within a continuous stream of information symbols, and the receivers for this particular system are expected work in a severe frequency selective multipath environment with long delay spreads relative to the length of the training sequence. The iterative procedure calculates the (semi-blind) Best Linear Unbiased Estimate (BLUE) of the CIR. The non-iterative version is an approximation to the BLUE CIR estimate, denoted by a-BLUE, achieving almost similar performance, with much lower complexity. Indeed we show that, with reasonable assumptions, a-BLUE channel estimate can be obtained by using a stored copy of a pre-computed matrix in the receiver which enables the use of the initial CIR estimate by the subsequent equalizer tap weight calculator. Simulation results are provided to demonstrate the performance of the novel algorithms for 8-VSB ATSC Digital TV system. We also provide a simulation study of the robustness of the a-BLUE algorithm to timing and carrier phase offsets.Conference Object Citation - WoS: 1Citation - Scopus: 2Fisher's Linear Discriminant Analysis Based Prediction Using Transient Features of Seismic Events in Coal Mines(Institute of Electrical and Electronics Engineers Inc., 2016) Köktürk Güzel, Başak Esin; Karaçalı, BilgeIdentification of seismic activity levels in coal mines is important to avoid accidents such as rockburst. Creating an early warning system that can save lives requires an automated way of predicting. This study proposes a prediction algorithm for the AAIA'16 Data Mining Challenge: Predicting Dangerous Seismic Events in Active Coal Mines that is based on transient activity features along with average indicators evaluated by a Fisher's linear discriminant analysis. Performance evaluation experiments on the training datasets revealed an accuracy level of around 0.9438 while the performance on the test dataset was at a level of 0.9297. These results suggest that the proposed approach achieves high accuracy in predicting danger seismic events while maintaining low complexity.Article The Performance Comparison of European Dttv Standards With Ldpc-Encoded Standard Under Awgn Channel(Springer Verlag, 2013) Karakuş, OktayIn this study, in addition to previous work which is a performance comparison of European DTTV Broadcasting standards which are known as DVB-T and DVB-T2, DVB-T2's inner encoder/interleaver block which has LDPC Encoder/Bit Interleaver, is integrated into DVB-T instead of its own inner encoder/interleaver block. This Proposed System's performance under AWGN channel is compared to the DVB-T/T2 standards. The Proposed System achieves better performance results according to DVB-T and very close results according to DVB-T2. It achieves nearly from 4 to 7 decibels SNR gain and up to 13 Mb/s data rate gain then DVB-T results according to different code rate and modulation parameters.Conference Object Citation - Scopus: 1Nonlinear Robust Control To Maximize Energy Capture in a Variable Speed Wind Turbine Using an Induction Generator(Institute of Electrical and Electronics Engineers Inc., 2009) Iyasere, Erhun; Dawson, Darren M.; Wagner, John R.; Salah, Mohammed; Tatlıcıoğlu, EnverThe emergence of wind turbine systems for electric power generation can help satisfy the growing global demand. This paper proposes a control strategy to maximize the wind energy captured in a variable speed wind turbine, with an internal induction generator, at low to medium wind speeds. The proposed strategy controls the tip speed ratio, via the rotor angular speed, to an optimum point at which the efficiency constant (or power coefficient) is maximal for a particular blade pitch angle and wind speed. This control method allows for aerodynamic rotor power maximization without exact wind turbine model knowledge.