Elektrik Elektronik Mühendisliği Bölümü Yayın Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/411

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Citation - WoS: 43
Citation - Scopus: 53
Application of normal wiggly dual hesitant fuzzy sets to site selection for hydrogen underground storage
(Pergamon-elsevier Science Ltd, 2019) Narayanamoorthy, Samayan; Baleanu, Dumitru; Ramya, L.; Baleanu, Dumitru; Kureethara, Joseph Varghese; Annapoorani, V; 56389; Matematik
The hesitant fuzzy set is a mathematical tool to express multiple values in decision making. If they could not give a resolution, it is important to give priority and importance to a number of different values. Here, we propose normal wiggly dual hesitant fuzzy set (NWDHFS), as an extension of normal wiggly hesitant fuzzy set. We define a new score function of normal wiggly dual hesitant fuzzy information. The NWDHFS can express deep ideas of membership and non-membership information. In this work, we use hesitant fuzzy set to expose the deepest ideas hidden in the thought-level of the decision makers. We show that the NWDHFS can handle the hesitant fuzzy information. It expresses the deeper ideas of hesitant fuzzy set. An illustration is provided to demonstrate the practicality and effectiveness to the application of site selection of the underground storage of hydrogen. We are compelled to look for alternating fuels to suits changing weather conditions and increasing number of vehicles. This alternative fuel is necessary to control global warming and to be economically viable. Based on this, hydrogen gas is selected as a good alternative fuel. The most important statement is the saving of the selected hydrogen gas. Thus, when saving hydrogen fuel, a safe storage space must be selected. Here, we use the MCDM ideas by use of proposed NWDHFV method is to select the appropriate hydrogen underground storage location. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Citation - WoS: 8
Citation - Scopus: 8
Design of quantum sensor to duplicate European Robins navigational system
(Elsevier Science Sa, 2021) Salmanogli, Ahmad; Gokcen, Dincer
In this article, we design a quantum device to duplicate the European Robins procedure to precisely deter-mine the migratory route. In the mentioned procedure, the important issue is the geomagnetic field effect on the magnetic momentum of the created radical pairs (triplet-singlet states) dancing with a special fre-quency. To duplicate the procedure, a quantum sensor consisting of two coincident tripartite systems is designed. Each tripartite system is independently excited with the entangled photons (signal and idler). The interesting point is that by manipulation of the system in the right condition, the microwave cavities modes separately affected by the entangled photons can be entangled. The entangled microwave photons play the same role as the triplet-singlet states present in the bird's navigational system. The key point in the design of the quantum sensor is that the entanglement between microwave photons can be strongly affected by the external magnetic field. In fact, this is the criterion employed by the quantum sensor to sense the magnetic field intensity and the direction. To analyze the system, the canonical quantization (or microscopic) method is used to determine the sensor's Hamiltonian, and also the system dynamics equations of motions are analytically derived using Heisenberg-Langevin equations. (c) 2021 Elsevier B.V. All rights reserved.
Citation - WoS: 6
Citation - Scopus: 6
Entangled microwave photons generation using cryogenic low noise amplifier (transistor nonlinearity effects)
(Iop Publishing Ltd, 2022) Salmanogli, Ahmad
This article mainly focuses on important quantum phenomenon called entanglement arising the nonlinearity property. This study uses a unique approach in which transistor nonlinearity effect (third-order nonlinearity) entangled microwave photons are created in a cryogenic low-noise amplifier (LNA). For entanglement analysis, the Hamiltonian of the designed cryogenic LNA (containing two coupled oscillators) is derived, and then, using the dynamic equation of motion, the oscillator's number of photons and the phase-sensitive cross-correlation factor are calculated in the Fourier domain to calculate the entanglement metric. The oscillators are coupled to each other through the gate-drain capacitor, and nonlinear transconductance is as an important factor strongly manipulating the entanglement. As a main conclusion, the study shows that the designed circuit using transistor third-order nonlinearity has the ability to generate the entangled microwave photons at very low intrinsic transconductance and more importantly when the noise figure (NF) is strongly minimized. As a complementary task, the printed circuit board of the cryogenic LNA is designed and simulated to verify the ability of the circuit to achieve an ultralow NF, by which the probability of the generation of entangled microwave photons is increased.
Citation - WoS: 16
Citation - Scopus: 16
Entanglement Sustainability Improvement Using Optoelectronic Converter in Quantum Radar (Interferometric Object-Sensing)
(Ieee-inst Electrical Electronics Engineers inc, 2021) Salmanogli, Ahmad; Gokcen, Dincer
In this study, the main focus is laid on the design of an optoelectronic converter as a part of the quantum radar to enhance the entanglement between retained and returned modes at high temperatures. The electro-opto-mechanical converter has been widely studied, and the results showed that the operation at high temperature is so crucial to generate and preserve the entanglement between modes. The main problem arises because the mechanical part operating at a low frequency leads to a large number of thermally excited photons, and eventually, the entanglement between modes becomes lost. To solve the problem, we replace the mechanical part with the optoelectronic components. The optical cavity is coupled to the microwave cavity in the newly designed system through a Varactor diode excited by a photodetector. As the main goal, to improve the entanglement sustainability, the effect of the coupling factor of the microwave cavity to photodetector is investigated. The results show that the mentioned factor creates some degrees of freedom to enhance the entanglement at high temperatures compared to the electro-opto-mechanical converter. At some specific values of the coupling factor, the retained and returned fields remained completely entangled up to 5.5 K and partially entangled around 50 K.
Citation - Scopus: 20
Entanglement Sustainability in Quantum Radar
(Institute of Electrical and Electronics Engineers Inc., 2020) Salmanogli, A.; Gokcen, D.; Gecim, H.S.; 182579
In this study, some important parts of a quantum radar are designed using the quantum electrodynamics theory and significantly focused on entanglement conservation. Quantum radar is generally defined as a detection sensor that utilizes the microwave photons like a classical radar and simultaneously employs quantum phenomena to improve detection, identification, and resolution capabilities. However, the entanglement is so fragile, unstable, and difficult to preserve for a long time. Also, more importantly, the entangled states have a tendency to leak away due to the noise. The points mentioned enforces that the entangled states should be carefully studied at each step of the quantum radar detection processes such as the creation of the entangled photons in the tripartite system, the amplification of the photons, the propagation into the atmosphere, and the reflection from the target. At each step, the parameters related to the real mediums and target material can affect the entangled states to leak away easily. The results of simulations indicate that the features of the tripartite system and amplifier are so important to lead the detected photons to remain entangled with the optical modes. Nonetheless, it is found that a lot of entangled photons lose the related non-classical correlation. © 2020 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission. See https://www.ieee.org/publications/rights/index.html for more information.
Citation - WoS: 1
Citation - Scopus: 3
FEM-based optimal design and testing of synchronous magnetic coupling for aerospace Starter/Generator applications
(Elsevier - Division Reed Elsevier india Pvt Ltd, 2023) Arslan, Sami; İskender, İres; Iskender, Ires; Navruz, Tugba Selcen; 133746; Elektrik-Elektronik Mühendisliği
Improvements in high energy density rare-earth permanent magnets make it innovative to develop magnetic couplings for Starter/Generator applications in the light of more electric aircraft to ensure magnetically insulated contactless power transmission between decoupled shafts for safe operation. Although there are essential studies on magnetic couplings in the literature, especially those for aerospace Starter/Generator structures are rarely encountered. However, methodologies considering system constraints and examining design parameters of couplings are in demand. In response to such a need, this paper proposes the novel design of highly reliable synchronous radial magnetic couplings with torque requirements of 6 and 12 N.m to isolate Starter/Generator and piston engine shafts in model aircraft. The preliminary volume is obtained analytically. Simulations are executed by optimetric approaches in Ansys Maxwell 2D. Optimisation techniques are compared in Maxwell 3D to get the final shape. The retaining sleeve of 0.5 mm is suggested. Loss of synchronisation in the event of the piston shaft failure or exceeding the maximum torque of the coupling is also examined. The torque fluctuation at load changes is 0.1%. Performance tests are conducted on the direct dynamic test bench. Absolute error margin is 37% for the Virtual Work method, 13% for 2D FEM and 6% for 3D FEM. The coupling efficiency is 93.8% at the maximum operating speed and the critical angle, and 96.9% at the minimum torque angle and the minimum operating speed.(c) 2023 Karabuk University. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Citation - WoS: 9
Citation - Scopus: 13
Fiber-Coupling Efficiency of Laser Array Beam From Turbulent Atmosphere to Fiber Link
(Ieee-inst Electrical Electronics Engineers inc, 2023) Gokce, Muhsin Caner; Gökçe, Muhsin Caner; Baykal, Yahya; Ata, Yalcin; 7812; Elektronik ve Haberleşme Mühendisliği
Free-space optical communication (FSOC) systems are nowadays integrated with fiber optical components developed for fiber-optic communications. In such integrated systems, the collected portion of the incident beam on the receiver lens is coupled into a single-mode fiber. The process of coupling, however, is mostly affected by the atmospheric turbulence which distorts the coherency of the propagating beam i.e., it results in speckle over the coupling lens causing a reduction in the coupling efficiency. In this article, we aimed at investigating the fiber coupling efficiency of laser array beams propagating in a turbulent atmosphere. For this purpose, using the Huygens-Fresnel principle, mutual coherence function (MCF) for a laser array beam incidence is formulated. In this way, the average power coupled into the fiber and the average received power on the coupling lens are derived for a laser array beam incidence. It is found that the fiber coupling efficiency clearly increases with the increase in ring radius and the number of Gaussian beams in the array and rapidly decreases with increasing structure constant of atmosphere, link distance, and the number of speckles over the receiver aperture. We also demonstrate the effect of various FSOC system parameters on the coupling efficiency.
Citation - WoS: 1
Citation - Scopus: 1
Finite Element Method-Based Optimisation of Magnetic Coupler Design for Safe Operation of Hybrid UAVs
(Mdpi, 2023) Arslan, Sami; İskender, İres; Iskender, Ires; Navruz, Tugba Selcen; 133746; Elektrik-Elektronik Mühendisliği
The integration of compact concepts and advances in permanent-magnet technology improve the safety, usability, endurance, and simplicity of unmanned aerial vehicles (UAVs) while also providing long-term operation without maintenance and larger air gap use. These developments have revealed the demand for the use of magnetic couplers to magnetically isolate aircraft engines and starter-generator shafts, allowing contactless torque transmission. This paper explores the design aspects of an active cylindrical-type magnetic coupler based on finite element analyses to achieve an optimum model for hybrid UAVs using a piston engine. The novel model is parameterised in Ansys Maxwell for optimetric solutions, including magnetostatics and transients. The criteria of material selection, coupler types, and topologies are discussed. The Torque-Speed bench is set up for dynamic and static tests. The highest torque density is obtained in the 10-pole configuration with an embrace of 0.98. In addition, the loss of synchronisation caused by the piston engine shaft locking and misalignment in the case of bearing problems is also examined. The magnetic coupler efficiency is above 94% at the maximum speed. The error margin of the numerical simulations is 8% for the Maxwell 2D and 4.5% for 3D. Correction coefficients of 1.2 for the Maxwell 2D and 1.1 for 3D are proposed.
Citation - WoS: 12
Citation - Scopus: 12
Intensity fluctuations of laser array beams in non-kolmogorov turbulence
(Ieee-inst Electrical Electronics Engineers inc, 2015) Gercekcioglu, Hamza; Baykal, Yahya; 7812
On-axis intensity fluctuations of laser array beams are evaluated when they are used in a weakly turbulent non-Kolmogorov atmosphere. Our formulation of the scintillation index is based on the Rytov method, which in the limiting case, correctly reduces to the known Gaussian beam scintillation index in weak Kolmogorov turbulence. When the radius of the ring (on which the array beamlets are placed), number of beamlets forming the laser array, source size of the beamlets, propagation distance or the wavelength is fixed, a decrease in the power law exponent of the non-Kolmogorov spectrum is found to decrease the scintillation index. Examining for any realization of the non-Kolmogorov spectrum, it is observed that an increase in the ring radius, number of beamlets, wavelength, and decrease in the source size of the beamlet, propagation distance reduces the intensity fluctuations.
Citation - WoS: 20
Citation - Scopus: 21
Multimode laser beam scintillations in non-kolmogorov turbulence
(Ieee-inst Electrical Electronics Engineers inc, 2015) Baykal, Yahya; 7812
Employing the Rytov solution, the scintillation index at the origin of the receiver plane is evaluated in non-Kolmogorov weak atmospheric turbulence when multimode laser incidence is used. The solution presented can be used when the multimode is composed of even modes. The novelty of this work lies in the theoretical combination of multimode laser beam excitation and non-Kolmogorov turbulence in the scintillation evaluations, which is not known both theoretically and experimentally. The study involves mathematical rigor but no experimental results. Being valid for any power law exponent of the non-Kolmogorov turbulence, the scintillations of the multimode beams are found to be smaller than the scintillation index of a single Gaussian beam. For the multimode laser beam excitation, the scintillation index is smaller at smaller power law exponent values. If the multimode content is formed by beams with larger mode numbers, the scintillations decrease for any non-Kolmogorov realization. When large sized beams are used in the multimode, the scintillations increase as compared to small sized content, and the scintillations become almost the same as the Gaussian beam scintillations. Comparing the multimode structures that have the same number of beams, the ones with higher order modes yield smaller scintillations, and for such multimode structures, very similar scintillation index behaviour versus the power law exponent can be obtained by varying the amplitudes of the modes composing the multimode. The main contribution of this paper is the formulation and evaluation of the scintillation noise in order to understand whether the use of multimode laser excitation will improve the link performance of optical wireless communication systems operating in a non-Kolmogorov atmosphere.
Citation - WoS: 5
Citation - Scopus: 6
Optical and Microcavity Modes Entanglement by Means of Plasmonic Opto-Mechanical System
(Ieee-inst Electrical Electronics Engineers inc, 2020) Salmanogli, Ahmad; Gecim, H. Selcuk; 182579
In this study, plasmonic opto-mechanical tripartite system is proposed to improve the performance of the traditional tripartite opto-mechanical system. In the new design, significantly, optical cavity and microwave cavity modes are directly coupled to each other. The originality of this work consists in embedding a microsphere in the optical cavity where the plasmon-plasmon interaction between the metal plates generates a plasmon mode inside the optical cavity and changes the electric field distribution. The plasmonic property influences the microsphere electrical properties and interacts with the photonic mode inside the optical cavity by which the microwave cavity properties are also affected through coupling to the optical cavity. Microsphere introduces a capacitor as a function of plasmonic properties that can strongly influence the microwave cavity resonance frequency. That is the feature that we want to utilize to enhance the performance of the system at high temperature. The results show that the optical cavity and microwave cavity modes remain entangled at high temperature. It is contributed to the plasmonic-based capacitor induced by the microsphere which is not affected by the thermally induced photons (noise). It is worth mentioning that the induced noise strongly restricts the traditional tripartite system operated with a wide bandwidth.
Citation - WoS: 5
Citation - Scopus: 5
Plasmonic Effect on Quantum-Dot Photodetector Responsivity
(Ieee-inst Electrical Electronics Engineers inc, 2019) Salmanogli, Ahmad; Gokcen, Dincer; Gecim, H. Selcuk; 280089; 182579
In this paper, we analyze and simulate the plasmonic effect on the quantum-dot photodetector responsivity. For this purpose, a plasmonic-based quantum-dot photodetector is designed in which a few quantum dots are embedded in the hot-spot regions of the plasmonic nanoparticles, wherein a high-intensity localized field is created. Notably, due to the maximum overlapping of the plasmonic field with the quantum dots at the hot spot, some of the optical characteristics of the quantum dot, particularly the spontaneous emission decay rate, are changed. This paper focuses on the engineering of the decay rate, through which we found that the quantum-dot photodetector responsivity is strongly enhanced with the order of 100 times at the visible range. For analyzing the proposed system, we first work on the plasmonic effect of the nanoparticle on the quantum-dot lifetime using the Heisenberg-Langevin equations. It is shown that by embedding the quantum dots at the hot spot of the nanoparticle, the decay rate of the quantum dot is dramatically influenced. In the following, plasmonic-quantum dot system responsivity is theoretically examined using a time-varying perturbation theory. Using this approach is necessary because the spontaneous emission cannot be analyzed with the classical methods. Consequently, it is proved that using plasmonic effect leads to enhanced photodetector responsivity, suggesting that even very small incoming signals are detectable.
Citation - WoS: 7
Citation - Scopus: 7
Plasmonic System as a Compound Eye: Image Point-Spread Function Enhancing by Entanglement
(Ieee-inst Electrical Electronics Engineers inc, 2018) Salmanogli, Ahmad; Gecim, H. Selcuk; Piskin, Erhan; 280089
In this paper, we introduce a plasmonic system that can operate as a compound eye. Based on the advantages mentioned in some previous works for the compound eye, we designed a plasmonic system that contains faraway plasmonic nanoparticles (NPs) that act independently like an ommatidium in the compound eye. This plasmonic system performance is analyzed with full quantum theory by which it is theoretically proved that with the interaction of light with NPs, the scattering light, and generated phonon can be entangled due to the NPs Ohmic loss. Consequently, the quantum states of the system before, after, and during the absorption and scattering of the incident photon, were quantum mechanically subjected. By the introduced theoretical formula and modeling results, it is shown that the plasmonic system can operate similar to the compound eye, if the critical parameters, such as system's focus point, NPs scattering angle, and inter-distance between NPs are suitably designed. More importantly, due to the entanglement between the scattering light and the generated phonon, it is theoretically proved that the point-spread function is improved when the traditional lens in the compound eye is replaced by the plasmonic NPs leading to an enhanced image resolution. Finally, a simple conceptual design of the plasmonic system is presented and then a few contributed modeling results are introduced.
Citation - WoS: 38
Citation - Scopus: 44
Propagation of modified Bessel-Gaussian beams in turbulence
(Elsevier Sci Ltd, 2008) Eyyuboglu, Halil Tanyer; Hardalac, Firat; 7688
We investigate the propagation characteristics of modified Bessel-Gaussian beams traveling in a turbulent atmosphere. The source beam formulation comprises a Gaussian exponential and the summation of modified Bessel functions. Based on an extended Huygens-Fresnel principle, the receiver plane intensity is formulated and solved down to a double integral stage. Source beam illustrations show that modified Bessel-Gaussian beams, except the lowest order case, will have well-like shapes. Modified Bessel-Gaussian beams with summations will experience lobe slicing and will display more or less the same profile regardless of order content. After propagating in turbulent atmosphere, it is observed that a modified Bessel-Gaussian beam will transform into a Bessel-Gaussian beam. Furthermore it is seen that modified Bessel-Gaussian beams with different Bessel function combinations, but possessing nearly the same profile, will differentiate during propagation. Increasing turbulence strength is found to accelerate the beam transformation toward the eventual Gaussian shape. (c) 2007 Elsevier Ltd. All rights reserved.
Citation - WoS: 3
Citation - Scopus: 5
Scintillation of Laser Beams in Weak Atmospheric Turbulence for Aerial Vehicle in the Use of LIDAR
(Ieee-inst Electrical Electronics Engineers inc, 2022) Gercekcioglu, Hamza; Baykal, Yahya Kemal; Baykal, Yahya; 7812; Elektrik-Elektronik Mühendisliği
Formulation of on-axis scintillation of laser beams is found in weak atmospheric turbulence for aerial vehicle in the use of light detection and ranging (LIDAR) systems by employing the Rytov method. The formulation derived for collimated Gaussian, plane and spherical beams is evaluated in vertical link involving up/down link. In this medium, the behavior of these beams in terms of deterioration is examined. In this context, the on-axis scintillation index values are plotted versus normalized target size parameter, target size, source size, propagation distance and zenith angle, and the results are obtained for LIDAR systems operating for aerial vehicle in vertical atmospheric link by using ground/space transceiver. The degradation is greater in operating with ground transceiver than in operating with space transceiver. Additionally, while the on-axis scintillation index is minimized in the smaller target size in use of ground transceiver than in use of space transceiver, that is, it can also be minimized in the larger target size in use of space transceiver. The values of source size and the normalized target size parameter minimizing the obtained scintillation index, are 1.2 cm, 10, and 6 cm and 5 for ground transceiver and space transceiver, respectively.
Citation - WoS: 16
Citation - Scopus: 15
Transmittance of multi Gaussian optical beams for uplink applications in atmospheric turbulence
(Ieee-inst Electrical Electronics Engineers inc, 2015) Ata, Yalcin; Baykal, Yahya; 7812
On-axis slant path uplink transmittance (used in short as transmittance throughout the text) for multi Gaussian optical beam in Kolmogorov atmospheric turbulent medium is investigated. It is observed that for both the flat-topped and the annular beams, as the propagation distance, wind speed and the zenith angle increase, the transmittance decreases. The transmittance of flat-topped beams increases when the number of beams, source size or the wavelength increases. For the annular beam, when the outer/inner beam size ratio is kept constant, larger source sizes yield larger transmittance values. Transmittance of the thicker annular beams is found to be larger than the transmittance of the thinner annular beams.
Citation - WoS: 58
Citation - Scopus: 71
Underwater turbulence, its effects on optical wireless communication and imaging: A review
(Elsevier Sci Ltd, 2022) Baykal, Yahya; Ata, Yalcin; Gokce, Muhsin C.
Theory of optical turbulence in underwater medium and the effects of underwater turbulence on various ap-plications done in underwater or under ocean are reviewed. A detailed survey of underwater turbulence studies in literature is reported. Underwater physics covering salinity, temperature and dissipation rates, various power spectra such as Hill, Nikishov and Nikishov, Li, new form and the oceanic turbulence optical power spectrum (OTOPS) spectra are explained. Wave and phase structure functions, related coherence length, anisotropy, in-tensity, field correlations in underwater turbulence are elaborated. Scintillation indices of spherical, plane, Gaussian, and other types of optical beams are mentioned. Bit-error-rate (BER), signal-to-noise-ratio (SNR) performances of optical wireless communication systems operating in underwater, and the effects of modulation types of these systems on the performances are reported. Channel capacity of underwater optical wireless communication systems when the channel experiences log-normal, gamma-gamma, Weibull, and negative exponential statistics are reflected. Underwater imaging and the related modulation transfer function, under-water turbulence mitigation techniques in the form of aperture averaging, adaptive optics, receiver, transmitter and multiple-input, multiple-output (MIMO) spatial diversity techniques are revised.

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