Elektrik Elektronik Mühendisliği Bölümü
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Browsing Elektrik Elektronik Mühendisliği Bölümü by Department "Çankaya Üniversitesi, Mühendislik Fakültesi, Elektrik-Elektronik Mühendisliği Bölümü"
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Conference Object Citation Count: Akan, E.; Akagündüz, E.; Uslu, I. B. (2021). "A data collection system design for hand gestures", 2021 International Conference on INnovations in Intelligent SysTems and Applications, INISTA 2021 - Proceedings.A data collection system design for hand gestures(2021) Akan, E.; Akagündüz, E.; Uslu, I. B.In this study, we aim at designing a smart glove, which consists of different inertial sensors and an EMG sensor and developing a human-machine interaction application by pre-processing and fusing these different sensory data. We also aim at providing solutions in cases where image processing-based approaches are inefficient. In the proposed smart glove, the quaternion-based orientation data to be produced by the magnetometer and gyroscope together, the acceleration data to be generated by the accelerometer, and the analog data generated by the EMG sensor are collected and then prepared for use by different applications. © 2021 IEEE.Article Citation Count: Kaplan, Alper; Akagündüz, Erdem (2020). "A Hybrid Framework for Matching Printing Design Files to Product Photos", Balkan Journal of Electrical and Computer Engineering, Vol. 8, No. 2, pp. 170-180.A Hybrid Framework for Matching Printing Design Files to Product Photos(2020) Kaplan, Alper; Akagündüz, Erdem; 233834We propose a real-time image matching framework, which is hybrid in the sense that it uses both hand-crafted features and deep features obtained from a well-tuned deep convolutional network. The matching problem, which we concentrate on, is specific to a certain application, that is, printing design to product photo matching. Printing designs are any kind of template image files, created using a design tool, thus are perfect image signals. However, photographs of a printed product suffer many unwanted effects, such as uncontrolled shooting angle, uncontrolled illumination, occlusions, printing deficiencies in color, camera noise, optic blur, et cetera. For this purpose, we create an image set that includes printing design and corresponding product photo pairs with collaboration of an actual printing facility. Using this image set, we benchmark various hand-crafted and deep features for matching performance and propose a framework in which deep learning is utilized with highest contribution, but without disabling real-time operation using an ordinary desktop computer.Article Citation Count: Preveze, B. (2018). "A Novel Analytical Method for Throughput Calculation of Wireless Ad-Hoc Networks Running Different Routing Algorithms ", International Journal of Research Studies in Electrical and Electronics Engineering, Vol.4, No.4, pp.1-10.A Novel Analytical Method for Throughput Calculation of Wireless Ad-Hoc Networks Running Different Routing Algorithms(2018) Preveze, Barbaros; 17573Because of the increasing number of internet related applications, the role of total router transmission delay became much more important for the service quality. For this purpose, the tunneling techniques have been widely used especially for real time multimedia transmission to have less number of route constructions and to be able to forward each packet at each router without the need of reaching the upper OSI (Open Systems Interconnection) layers. But, in mobile networks, since the network experience with more changes in traffic conditions and node locations, tunnels will be reconstructed for many times and some extra delay will occur to reconstruct these tunnels. In this work, the place of the tunneling algorithm is taken by the well-known MPLS (Multi-Protocol Label Switching) protocol and for confirmation the throughput calculations are made by considering two different routing algorithms, one of which is AEABR algorithm proposed in [1] (shown in [2] that it improves the system throughput w.r.t Fastest path Routing algorithm [3] for various vehicular velocities), and the other one is Fastest Path routing algorithm [3]. In this work a novel analytical method for throughput calculation of wireless ad-hoc networks running aforementioned routing algorıthms is proposed including the effects of extra delay caused by extra Route Reconstructions (RRC).Article Citation Count: Preveze, Barbaros (2020). "A Novel High Performance Routing Algorithm for Mobile Multi-hop Tunneling Networks", Wireless Personal Communications, Vol. 114, No. 1, pp. 1-27.A Novel High Performance Routing Algorithm for Mobile Multi-hop Tunneling Networks(2020) Preveze, Barbaros; 17573By the increased number of mobile devices, the demand of high speed connection oriented tunneling networks also increases. But, in mobile tunneling networks, the full route will have to be reconstructed more frequently because of more frequent route failures, where the requirements for extra route reconstructions (RRC) will cause extra delay and a decreased system throughput. In this work, a novel routing algorithm, optimum path routing (OPR) is proposed to extend the route life time of mobile multi hop tunneling networks and to increase the system throughput. On the other hand, as the most recent works in the literature indicate that, one of the greatest challenges of tunneling networks is to provide the network flexibility by instant adaptation on changing network conditions to keep the delay at lowest levels even in case of high traffic loads or node failures. To solve the aforementioned flexibility problem of the tunneling networks, a novel algorithm applicable to all kinds of routing algorithms called "avoid congested nodes (ACN)" is proposed. The results show that, the OPR algorithm proposed to increase the route life has succeeded in decreasing the RRC delay by 84% and improving the throughput by 20.17% with respect to the Fastest Path routing algorithm in the literature. And the ACN algorithm, proposed to provide a rapid adaptation of the nodes to the changing traffic conditions, has also succeeded in carrying back the throughput of the network with traffic load from 75.5% of its best performance evaluated with no traffic to its 94%.Article Citation Count: Preveze, Barbaros (2019). "A Novel Method For Performance Improvement of Slow Start Congestion Control Method In Packet Switched Networks", Uludağ Üniversitesi Mühendislik Fakültesi Dergisi, Vol. 24, No. 3, pp. 451-467.A Novel Method For Performance Improvement of Slow Start Congestion Control Method In Packet Switched Networks(2019) Preveze, Barbaros; 17573By the introduction of all IP networks with the smart homes, smart phones, car multimedia systems wearable technologies and IP TV’s, the number of internet related devices and the number of applications have increased. This has generated an increased quantity of bandwidth usage in packet switching networks. Therefore, the betterment of the bandwidth usage and the system performance has become more significant. Thus, there is a large number of works in the literature attempting to improve the network performance. For this purpose, generally the modifications of used methods in the network structures are preferred, rather than making major hardware based modifications requiring more financial support. In this work, a novel method called Return Back to threshold (RBT) is proposed to be applied to packet switched networks for a better congestion control.Conference Object Citation Count: Demirkutlu, E.; İskender, İ. "A Novel Transformerless Single-Phase Three-Level Buck-Boost Inverter", 2023 IEEE Applied Power Electronics Conference And Exposition, APEC, Proceedings, pp. 114-120, 2023.A Novel Transformerless Single-Phase Three-Level Buck-Boost Inverter(2023) Demirkutlu, Eyyup; Iskender, Ires; 133746This paper proposes a novel transformerless, single-phase, three-level, buck-boost inverter. The proposed inverter can suppress the leakage current drawn from the input power source and provide a long-lasting solution for applications with a wide range and unregulated input voltage. Unlike similar topologies, in the proposed inverter there is no need to have a mid-point of DC sources or DC bus capacitors at the input side of the inverter. A single-phase, three-level, buck-boost inverter for realizing the power stage with 110-Vrms output AC voltage and a range of 100V-200V input DC voltage is investigated in this study. The proposed topology has been proven through theory, computer simulations, and experimental studies with SiC MOSFETs-based prototype of a 300-VA power supply. Theory, computer simulation, and experimental results are all correlated.Article Citation Count: Baykal, Yahya (2020). "Adaptive optics corrections of scintillations of Hermite-Gaussian modes in an oceanic medium", Applied Optics, Vol. 59, No. 16, pp. 4826-4832.Adaptive optics corrections of scintillations of Hermite-Gaussian modes in an oceanic medium(2020) Baykal, Yahya; 7812Adaptive optics correction of the scintillation index is found when Hermite-Gaussian laser beams are used in oceanic turbulence. Adaptive optics filter functions are used to find how the tilt, focus, astigmatism, coma, and total correction will behave under high order mode excitation. Reduction of the oceanic scintillation under various oceanic turbulence and system parameters is examined under different high order modes. Also, the effects of the source size, wavelength, and link length on the total adaptive optics correction of Hermite-Gaussian modes in an oceanic medium are investigated for different modes. (C) 2020 Optical Society of AmericaArticle Adaptive optics effect on performance of BPSK-SIM oceanic optical wireless communication systems with aperture averaging in weak turbulence(2020) Gökçe, Muhsin Caner; Baykal, Yahya; Ata, Yalçın; 7812Turbulence-induced wavefront deformations cause the irradiance of an optical signal to fluctuate resulting a in serious degradation in the bit-error-rate (BER) performance of optical wireless communication (OWC) system. Adaptive optics is an effective technique to compensate for the wavefront aberrations to reduce the fluctuations in the received intensity. In this paper, we investigate how the adaptive optics technique affects the BER performance of an oceanic OWC (OOWC) system employing binary phase shift keying-subcarrier intensity modulation (BPSK-SIM) and aperture averaging. To evaluate BER performance in weak oceanic turbulence, the required entities such as the received optical power captured by a circular aperture and the aperture averaged scintillation index measuring the fluctuations in the received irradiance are derived. The effect of adaptive optics correction of various wavefront aberrations (i.e., tilt, defocus, astigmatism and the coma) on the BER performance is illustrated and the performance of the adaptive optics-OOWC system is compared to that of a non-adaptive optics OOWC system by the metric defined. (C) 2020 Elsevier Ltd. All rights reserved.Article Citation Count: Salmanogli, Ahmad; Gökçen, Dinçer (2020). "Analysis of Quantum Radar Cross-Section by Canonical Quantization Method (Full Quantum Theory)", IEEE Access, Vol. 8, pp. 205487-205494.Analysis of Quantum Radar Cross-Section by Canonical Quantization Method (Full Quantum Theory)(2020) Salmanogli, Ahmad; Gökçen, DinçerThis article investigates the difference between two quantum-based theories to calculate the radar cross-section (RCS). Quantum radar cross-section (QRCS) has been commonly analyzed using the dipole approximation method, and the related results show that it can improve the sidelobe of the interference pattern in contrast to the classical methods. This study, on the other hand, utilizes the canonical quantization (or microscopic) method, which is a more comprehensive theory than the dipole approximation method to calculate the radar cross-section. It is shown that there are some similarities between two methods; nonetheless, there are some crucial quantities and factors that have been ignored in the dipole approximation methods. The main difference arises due to the interaction Hamiltonian that two methods relied on. The theoretical calculation shows some critical points suggesting that the dipole approximation method cannot cover all aspects of the radar cross-section calculation. To verify the mentioned point, we establish a new method in which the radar cross-section is calculated by merging the quantum approach with the method of moment (MoM), called quantum-method of moment (QMoM). The simulation results show that the newly established method is in harmony with the canonical quantization method.Article Citation Count: Ata, Yalçın; Baykal, Yahya (2020). "Anisotropic non-Kolmogorov turbulence effect on transmittance of multi-Gaussian beam", Waves in Random and Complex Media, Vol. 30, No. 1, pp. 118-129.Anisotropic non-Kolmogorov turbulence effect on transmittance of multi-Gaussian beam(2020) Ata, Yalçın; Baykal, Yahya; 7812The effect of anisotropic non-Kolmogorov turbulent atmosphere on multi-Gaussian beam is investigated and the results are presented against different beam and medium parameters. Results show that anisotropy increases the power efficiency of wireless communication systems. Besides anisotropy, turbulence effects on the multi-Gaussian optical beam are represented versus the beam source size, beam flatness order, propagation distance, inner scale length, turbulence strength, non-Kolmogorov turbulence power law exponent, wavelength, inner and outer source sizes for flat-topped and annular beams.Article Citation Count: Şener, G. (2023). "Antenna Synthesis by Levin's Method using a Novel Optimization Algorithm for Knot Placement", Applied Computational Electromagnetics Society Journal, Vol.38, No.2, pp.74-79.Antenna Synthesis by Levin's Method using a Novel Optimization Algorithm for Knot Placement(2023) Şener, Göker; 17740Antenna synthesis refers to determining the antenna current distribution by evaluating the inverse Fourier integral of its radiation pattern. Since this inte-gral is highly oscillatory, Levin's method can be used for the solution, providing high accuracy. In Levin's method, the integration domain is divided into equally spaced sub-intervals, and the integrals are solved by transfer-ring them into differential equations. This article uses a new optimization algorithm to determine the location of these interval points (knots) to improve the method's accuracy. Two different antenna design examples are pre-sented to validate the accuracy and efficiency of the pro-posed method for antenna synthesis applications.Article Citation Count: Baykal, Yahya; Gökçe, Muhsin Caner; Ata, Yalçın (2020). "Application of adaptive optics on bit error rate of M-ary pulse-position-modulated oceanic optical wireless communication systems", Laser Physics, Vol. 30, No. 7.Application of adaptive optics on bit error rate of M-ary pulse-position-modulated oceanic optical wireless communication systems(2020) Baykal, Yahya; Gökçe, Muhsin Caner; Ata, Yalçın; 7812An adaptive optics correction arising from the sum of tilt, focus, astigmatism and coma components is applied to the bit error rate (BER) of M-ary pulse-position-modulated (PPM) oceanic optical wireless communication systems. The percentage reduction in BER is evaluated versus the oceanic turbulence parameters of the ratio of temperature to salinity contributions to the refractive index spectrum, the rate of dissipation of mean-squared temperature and that of kinetic energy per unit mass of fluid under different data bit rates, avalanche photodiode (APD) average current gains and the M values of the M-ary PPM. Our findings indicate that the percentage reduction in BER becomes larger when the ratio of temperature to salinity contributions to the refractive index spectrum or the rate of dissipation of mean-squared temperature or the data bit rate or the M value of the M-ary PPM is smaller, and when the rate of dissipation of kinetic energy per unit mass of fluid or the APD average current gain is larger.Article Citation Count: Yurtseven, H.H.; Kiracı, A. (2017). "BaCeO3'in rhombohedral-tetragonal faz geçişi için Raman frekansından sıcaklığın bir işlevi olarak hesaplanan sönüm sabiti, dielektrik duyarlılık, ters gevşeme zamanı ve aktivasyon enerjisi", Balıkesir Üniversitesi Fen Bilimleri Enstitüsü Dergisi, Vol.19, No.3, pp.77-83.BaCeO3'in rhombohedral-tetragonal faz geçişi için Raman frekansından sıcaklığın bir işlevi olarak hesaplanan sönüm sabiti, dielektrik duyarlılık, ters gevşeme zamanı ve aktivasyon enerjisi(2017) Yurtseven, Hasan Hamit; Kiracı, Ali; 42475kristalinin ferroelektrik fazında (TArticle Citation Count: Çil, Celal Zaim...et al (2010). "Beam wander of J (0)- and I (0)-Bessel Gaussian beams propagating in turbulent atmosphere", Applied Physics B-Lasers and Optics, Vol. 98, No. 1, pp. 195-202.Beam wander of J (0)- and I (0)-Bessel Gaussian beams propagating in turbulent atmosphere(2010) Çil, Celal Zaim; Eyyüboğlu, Halil Tanyer; Baykal, Yahya Kemal; Korotkova, O.; Cai, Y.; 7812Root mean square (rms) beam wander of J (0)-Bessel Gaussian and I (0)-Bessel Gaussian beams, normalized by the rms beam wander of the fundamental Gaussian beam, is evaluated in atmospheric turbulence. Our formulation is based on the first and the second statistical moments obtained from the Rytov series. It is found that after propagating in atmospheric turbulence, the collimated J (0)-Bessel Gaussian and the I (0)-Bessel Gaussian beams have smaller rms beam wander than that of the Gaussian beam, regardless of the choice of Bessel width parameter. However, the extent of such an advantage depends on the chosen width parameter, Gaussian source size, propagation distance and the wavelength. Focusing at finite distances of the considered beams causes the rms beam wander to decrease sharply at the propagation distances equal to the focusing parameter.Article Citation Count: Çil, Ç.Z.;...et.al. (2010). "Beam wander of J 0- and i 0-Bessel Gaussian beams propagating in turbulent atmosphere", Applied Physics B: Lasers and Optics, Vol.98, No.1, pp.195-202.Beam wander of J 0- and i 0-Bessel Gaussian beams propagating in turbulent atmosphere(2010) Çil, C.Z.; Eyyuboğlu, H.T.; Baykal, Y.; Korotkova, O.; Cai, Y.; 7812Root mean square (rms) beam wander of J 0-Bessel Gaussian and I 0-Bessel Gaussian beams, normalized by the rms beam wander of the fundamental Gaussian beam, is evaluated in atmospheric turbulence. Our formulation is based on the first and the second statistical moments obtained from the Rytov series. It is found that after propagating in atmospheric turbulence, the collimated J 0-Bessel Gaussian and the I 0-Bessel Gaussian beams have smaller rms beam wander than that of the Gaussian beam, regardless of the choice of Bessel width parameter. However, the extent of such an advantage depends on the chosen width parameter, Gaussian source size, propagation distance and the wavelength. Focusing at finite distances of the considered beams causes the rms beam wander to decrease sharply at the propagation distances equal to the focusing parameter.Article Citation Count: Ata, Yalçın; Baykal, Yahya Kemal; Gökçe, Muhsin Caner (2022). "BER performance ofM-ary pulse position modulated communication systems in anisotropic non-Kolmogorov turbulent atmosphere", Waves in Random and Complex Media, Vol. 32, No. 2, pp. 936-946.BER performance ofM-ary pulse position modulated communication systems in anisotropic non-Kolmogorov turbulent atmosphere(2022) Ata, Yalçın; Baykal, Yahya Kemal; Gökçe, Muhsin Caner; 7812We investigated the effect of anisotropic non-Kolmogorov atmospheric turbulence on the performance of the optical wireless systems whenM-ary Pulse Position Modulation (PPM) is applied to a Gaussian beam. The performance of the optical wireless systems that use avalanche photodetector at the receiver is evaluated in terms of the bit error rate (BER). The effects of the parameters, such as the anisotropy factors inx-ydirections, modulation order, data bit rate, equivalent load resistor, photodetector quantum efficiency, non-Kolmogorov turbulence power law exponent, beam source size, link length, photodetector gain and structure constant on BER of theM-ary PPM Gaussian beam propagating in anisotropic non-Kolmogorov atmospheric turbulence, are examined.Article Citation Count: Kiracı, ali. (2022). "Calculation of the Halfwidth and the Activation Energy for the Soft Raman Modes in the Brominated Compounds of Tris-Sarcosine Calcium Chloride", Trends in Sciences, Vol.9, No.16.Calculation of the Halfwidth and the Activation Energy for the Soft Raman Modes in the Brominated Compounds of Tris-Sarcosine Calcium Chloride(2022) Kiracı, Ali; 42475This letter contributes how to calculate the anomalous behavior for the damping constant (halfwidth) of the ferroelectric Tris-Sarcosine Calcium Chloride (TSSC) and its brominated compounds TSSC1−xBrx (x = 0.13, 0.42 and 0.60) from the wavenumber data of the soft modes below the phase transition temperature of TC. The pseudospin-phonon coupled (PS) and the energy fluctuation (EF) models derived from the dynamical Ising model were used. Both PS and EF models have been used to contribute understanding the temperature dependence of the phase transition mechanism of TSSC1−xBrx. In addition, values of the activation energy for TSSC1−xBrx (x = 0, 0.13, 0.42 and 0.60) were extracted from the damping constant as calculated from both models (PS and EF). Our results indicate order-disorder type phase transition for TSSC1−xBrx.Article Citation Count: Kara, N.; Kiracı, A.; Yurtseven, H. (2022). "Calculation of the spin-lattice relaxation time and the activation energy near the IV–III phase transition in pyridinium fluorosulfonate (C5NH6)FSO3", Ferroelectrics, Vol.589, No.1, pp.45-54.Calculation of the spin-lattice relaxation time and the activation energy near the IV–III phase transition in pyridinium fluorosulfonate (C5NH6)FSO3(2022) Kara, N.; Kiracı, A.; Yurtseven, H.; 42475The spin-lattice relaxation time T1H for protons nuclei is calculated in term of the pseudospin–phonon (PS) coupled and the energy fluctuation (EF) models close to the IV–III solid–solid phase transition of (Formula presented.) in (C5NH6)FSO3. This calculation was performed by associating the observed second moment of the 1H as the order parameter below T C and the disorder parameter above T C. Values of the activation energy for the cation reorientation in this crystal are also deduced by using both models. In addition, the observed dielectric permittivity of this crystal is analyzed within the framework of the Landau theory and values of the spontaneous polarization (P S) are determined as a function of temperature. The normalized values of P S are used in the PS and EF models to extract the activation energy for the reorientation of the dipole moment of this compound arising from cation–anion interaction. Our results show that the PS and EF models can describe the observed behavior of the spin-lattice relaxation time adequately for the IV–III solid–solid transition in (C5NH6)FSO3.Conference Object Citation Count: Ülkü, İrem...at all (2020). "Comparison of single channel indices for U-Net based segmentation of vegetation in satellite images", Twelfth International Conference on Machine Vision, 2019, Amsterdam, Netherlands (ICMV2019).Comparison of single channel indices for U-Net based segmentation of vegetation in satellite images(2020) Ülkü, İrem; Barmpoutis, Panagiotis; Stathaki, Tania; Akagündüz, Erdem; 233834Article Citation Count: Kavak, H.; İskender, İ.; Jahi, A. (2018). "Conducted Emi Performance Comparison Of Si And Sic Mosfets In A Ccm Boost Pfc Converter For MIL-STD-461F CE102", Poznan University Of Technology Academic Journals.Conducted Emi Performance Comparison Of Si And Sic Mosfets In A Ccm Boost Pfc Converter For MIL-STD-461F CE102(2018) Kavak, Halil; İskender, İres; Jahi, Amir; 133746This paper presents a comparison of conducted EMI performance of Si and SiC MOSFETs in a CCM PFC boost converter that is designed to meet CE102 of MIL-STD461F. EMI performance comparison is based on MOSFET of the PFC converter. That is, the power switch of the converter is the only parameter that is changed during tests. The boost diode is kept the same during the tests and the type of the boost diode is SiC. The paper shows the CE102 test results of Si and SiC MOSFETs without an EMI filter at the input side of CCM PFC boost converter.
