Elektrik Elektronik Mühendisliği Bölümü Yayın Koleksiyonu

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

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Citation - Scopus: 0
A data collection system design for hand gestures
(Institute of Electrical and Electronics Engineers Inc., 2021) Akan, E.; Akagunduz, 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.
A Hybrid Framework for Matching Printing Design Files to Product Photos
(2020) Akagunduz, Erdem; Kaplan, Alper; 233834
We 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. 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 (SIFT, SURF, GIST, HoG) and deep features for matching performance. Various segmentation algorithms including deep learning based segmentation methods are applied to select feature regions. Results show that SIFT features selected from deep segmented regions achieves up to 96% product photo to design file matching success in our dataset. We propose a framework in which deep learning is utilized with highest contribution, but without disabling real-time operation using an ordinary desktop computer.
Citation - WoS: 9
Citation - Scopus: 14
A Machine Learning Study to Enhance Project Cost Forecasting
(Elsevier, 2022) Inan, Tolga; İnan, Tolga; Narbaev, Timur; Hazir, Oncu; Elektrik-Elektronik Mühendisliği
In project management it is critical to obtain accurate cost forecasts using effective methods. This study presents a Machine Learning model based on Long-Short Term Memory to forecast the project cost. The model uses the seven-dimensional feature vector, including schedule and cost performance factors and their moving averages as a predictor. Based on the cost variation patterns from the training phase, we validate the model using three hundred experiments in the testing phase. Overall, the proposed model produces more accurate cost estimates when compared to the traditional Earned Value Management index-based model. Copyright (C) 2022 The Authors.
Citation - WoS: 5
Citation - Scopus: 31
A New Narrow Band Dual-Mode Microstrip Slotted Patch Bandpass Filter Design Based On Fractal Geometry
(Ieee, 2012) Mezaal, Yaqeen S.; Eyyuboglu, Halil Tanyer; 7688
A narrowband, compact, and easily fabricated microstrip bandpass filter design is introduced in this paper as a candidate for use in modern wireless systems. The proposed filter design is based on the use of dual-mode (two pole) square slotted microstrip resonator. This microstrip bandpass filter has the advantages of possessing much narrower and sharper performance responses than those of the single mode resonator and conventional square patch filter. The proposed microstrip filter structure is fractally generated using Sierpinski fractal curve geometry applied to the conventional square microstrip patch. Filter structures resulting from the successive iterations in the fractal generation process show a considerably low insertion loss, and sharper response of about 1% fractional bandwidth as compared with the conventional microstrip square patch filter of 3% fractional bandwidth designed at the same frequency using the same substrate material. The performance of filter structures, based on dual-mode resonators up to the third iterations, has been evaluated using a full-wave based electromagnetic simulator Sonnet software package. Performance simulation results show that these filter structures offer narrower fractional bandwidth percentages as compared with other types of non- fractalized filter structures.
A Novel Method For Performance Improvement of Slow Start Congestion Control Method In Packet Switched Networks
(2019) Preveze, Barbaros; Preveze, Barbaros; 17573; Elektrik-Elektronik Mühendisliği
Tüm akıllı ağlar, akıllı telefonlar, araç multimedya sistemleri giyilebilir teknolojiler ve IP TV'ler ile tanışılmasıyla birlikte internet bağlantılı cihaz ve uygulamaların sayısı da oldukça artmaktadır. Bu durum, paket anahtarlama ağlarında bant genişliği kullanımı miktarında artışa sebep olmuştur. Böylece, bant genişliğinin etkin kullanımı ve sistem performansı daha önemli hale gelmiştir ve literatürde ağ performansını iyileştirmeye çalışan çok sayıda çalışma bulunmaktadır. Ağ yapılarında finansal destek gerektiren donanım tabanlı modifikasyonlar yapmak yerine daha çok, kullanılan yöntemlerin yazılımsal modifikasyonları tercih edilmektedir. Bu çalışmada, daha iyi bir tıkanıklık kontrolü için paket anahtarlamalı ağlarda Eşiğe Geri Dön (RBT) adı verilen yeni bir yöntem önerilmiştir.
Citation - WoS: 2
Citation - Scopus: 5
A Novel Transformerless Single-Phase Three-Level Buck-Boost Inverter
(Ieee, 2023) Demirkutlu, Eyyup; Iskender, Ires; 133746
This 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.
Amorf Çekirdekli Transformatörün Çoklu Fizik Yöntemiyle Elektromanyetik - Sıcaklık Analizi
(2021) Najafi, Atabak; İskender, İres; İskender, İres; 133746; Elektrik-Elektronik Mühendisliği
Bu makalede, Amorf nüveli transformatörün sıcaklık analizini detaylı incelemek için, ısı transferi, akışkan akışı ve elektromanyetik analizlerini kapsayan çok disiplinli bir yaklaşım kullanılmıştır. Transformatörün bobini ve çekirdeğindeki güç kayıpları incelenip, sıcaklık ve akışkan akış analizleri elektromanyetik bir model ile birleştirilmiştir. Önerilen yöntem, Amorf çekirdekli gibi özel transformatörlerde, önceki noktasal sıcaklık bilgisine ya da sıcaklık Gradyan değerlerine ihtiyaç duymadan, sıcaklık değişimini detaylı olarak tahmin edebilmektedir. Teorik çalışma sonuçları uluslararası standartlara göre Dyn11, 34.5/0.4-kV, 630-kVA’lik amorf çekirdekli transformatör üzerine uygulanan deneysel çalışma sonuçlarıyla doğrulanmıştır. Teorik ve pratik çalışma sonuçlarının karşılaştırılması, sonuçların büyük bir uyum içinde olduğunu göstermekte olup, kullanılan yöntem genç mühendislere güç transformatörlerin sıcaklık analiz çalışmalarında faydalı bir araç oluşturmaktadır.
Citation - WoS: 0
Citation - Scopus: 1
Analysis of Lightning Impulse Effects on Three Winding Transformer Used in Solar System Based ANSYS Maxwell
(Ieee, 2022) Yukselen, Emir; İskender, İres; Iskender, Ires; 133746; Elektrik-Elektronik Mühendisliği
Transformers are in more critical applications in the renewable energy world and having a transformer fail in such a cyclical power station can be disastrous. Over voltage or voltage strike is the most important phenomena for the transformers. Thus, the evaluating and estimating the effects and stresses of these sudden high voltages is important during the transformers life time operation and design stage. Accordingly in this paper the electromagnetic field analyses of the lightning impulse on Photovoltaic (PV) transformer are investigated using ANSYS Maxwell software. The 3D and 2D model simulation of the PV transformer is carried out to determine the electric field and voltage distribution on critical regions which can cause breakdown on insulation material and damage transformer windings and affects transformer working. Afterwards according to the simulation result, the subjected transformer was designed considering the relative critical regions and performs the full wave lightning impulse test in factory area to verify the dielectric strength of the transformer. This study provides better understanding of the lightning impulse voltage effects with localization of the critical regions on the PV transformer and helps to improve the withstand capability of the transformer against the lightning impulse voltages during the design and production stage.
Citation - Scopus: 3
Analysis of Short Circuit Electromagnetic Force in a Three Winding Transformer Used in Solar System
(Institute of Electrical and Electronics Engineers Inc., 2021) Jahi, A.; İskender, İres; Iskender, I.; 133746; Elektrik-Elektronik Mühendisliği
Due to the increasing of the fossil fuels prices in the past years and lack of these sources, all scientists encouraged to looking for the alternative energy sources. One of these energy sources is renewable solar energy. Power transmission from solar systems to grid is achieved using step up transformers. This type of transformer is energized from two inverter with or without variable frequency. Power transformers are deals with a variety of mechanical, electrical and thermal stresses during normal life time operation. Transient electromagnetic forces cause mechanical stress on transformer parameters where calculation of these forces with traditional methods is extremely complex due to the geometry of the transformer. Accordingly in this study, the electromagnetic forces takes place in the windings of a Photovoltaic (PV) transformer are investigated and for calculation of these forces, the 3D and 2D model of transformer is adapted in the ANSYS Workbench. The analysis of electromagnetic forces during the three line fault on high voltage side of the transformer are performed by the Finite Element Method (FEM) and compared with the analytical results. The numerical modeling technique discussed in this study would be useful in the design stage of PV transformer with regard to evaluate ability of transformer to withstand the short circuit current. © 2021 Chamber of Turkish Electrical Engineers.
Citation - WoS: 5
Citation - Scopus: 6
Anisotropic non-Kolmogorov turbulence effect on transmittance of multi-Gaussian beam
(Taylor & Francis Ltd, 2020) Ata, Yalcin; Baykal, Yahya; 7812
The 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.
Ardıl çeviri eğitiminde dikkat yönetimi ve çalışma belleği dinamikleri
(2019) Yemenici, Alev; 100753
Ardıl çeviri, çevirmenin yukarıdan-aşağıya dikkatini, aşağıdan-yukarıya dikkatini, dinlenme durumuağlarını ve çalışma belleğini yetkin biçimde yönetmesini gerektiren son derece zorlayıcı bir süreçtir.Çalışma belleğine bilginin girmesi ve işlenmesi ancak yukarıdan-aşağıya dikkatinin odaklanmasısonucu gerçekleşir. Bilginin işlenmesi sürecinde, çevirmenin kulağına gelen bilginin tanınması,çözümlenmesi ve anlamlandırılması üzerine çevirmen konuşmaya ilişkin bir kavrayış elde eder.Çevirmen yukarıdan-aşağıya dikkatini konuşmaya odaklanmak amacıyla korumaya çalışırken belleğiolumsuz yönde etkileyebilecek dinlenme durumu ağlarını ve aşağıdan-yukarıya dikkatini dedenetlemek durumundadır. Ancak bu şekilde çalışma belleğine girecek bilgi işlenerek artalanbilgisiyle bütünleştirileceğinden akıcı ve güvenilir bir çeviri yapılabilir. Bu makalede, sözlü çevirideyetkinlik noktasına ulaşabilmek için bilinmesi gereken bellek dinamikleri ve dikkat türleri üzerindedurulmakta, hem bilginin kodlanması hem de geri çağrılmasında çevirmenin işini kolaylaştıracakstratejilere değinilmekte, ayrıca ardıl çeviri sırasında ortaya çıkabilecek beklenmedik sorunlara bağlıolarak yaşanabilecek dikkat kaybının engellenmesine yönelik öneriler üzerinde durulmaktadır. Bumakalede dikkat ve bellek yönetiminin yanında ardıl çeviri eğitiminde önemli yer tutan ve hem bellekişleyişini hem de dikkat sistemlerini yöneten yürütücü biliş, stres ve sorunlarla başa çıkmastratejilerine de yer verilmiştir.
Citation - WoS: 6
Citation - Scopus: 6
Array of nanoparticles coupling with quantum-dot: Lattice plasmon quantum features
(Elsevier Science Bv, 2018) Salmanogli, Ahmad; Gecim, H. Selcuk; 182579
In this study, we analyze the interaction of lattice plasmon with quantum-dot in order to mainly examine the quantum features of the lattice plasmon containing the photonic/plasmonic properties. Despite optical properties of the localized plasmon, the lattice plasmon severely depends on the array geometry, which may influence its quantum features such as uncertainty and the second-order correlation function. To investigate this interaction, we consider a closed system containing an array of the plasmonic nanoparticles and quantum-dot. We analyze this system with full quantum theory by which the array electric far field is quantized and the strength coupling of the quantum-dot array is analytically calculated. Moreover, the system's dynamics are evaluated and studied via the Heisenberg-Langevin equations to attain the system optical modes. We also analytically examine the Purcell factor, which shows the effect of the lattice plasmon on the quantum-dot spontaneous emission. Finally, the lattice plasmon uncertainty and its time evolution of the second-order correlation function at different spatial points are examined. These parameters are dramatically affected by the retarded field effect of the array nanoparticles. We found a severe quantum fluctuation at points where the lattice plasmon occurs, suggesting that the lattice plasmon photons are correlated.
Citation - Scopus: 2
Associativity Tick Averaged Associativity Based Routing (Ataabr) for Real Time Mobile Networks
(2009) Převeze, B.; Preveze, Barbaros; Şafak, A.; 17573; Elektrik-Elektronik Mühendisliği
This study proposes a long lived routing method which is also based on Associativity such as ABR (Associativity Based Routing) for real time applications. The main purpose of our work is improving the ABR algorithm in order to reduce the outage of the nodes and decreasing the number of reconstructions required to keep the nodes in communication. The performance of ABR is compared with other long-lived relay selection algorithms for real-time applications.
Citation - WoS: 0
Citation - Scopus: 1
BER performance ofM-ary pulse position modulated communication systems in anisotropic non-Kolmogorov turbulent atmosphere
(Taylor & Francis Ltd, 2022) Baykal, Yahya Kemal; Ata, Yalcin; Baykal, Yahya; Gökçe, Muhsin Caner; Gokce, Muhsin Caner; 7812; Elektrik-Elektronik Mühendisliği; Elektronik ve Haberleşme Mühendisliği
We 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.
Citation - WoS: 0
Citation - Scopus: 0
Biomedical Device for Early Breast Cancer Detection: Device Performance Improving By Plasmonic-Photonic Mask
(Scitepress, 2019) Meral, Sanem; Yalcinkaya, Ezel; Eroglu, Metin; Salmanogli, Ahmad; Gecim, H. Selcuk; 280089
In this article, a new device to detect breast cancer at an early stage, is presented. The main advantages of the device are its easy operational procedure, portability, high accuracy due to usage of plasmonic-photonic mask and the low cost. In fact, the novelty of the device presented is to apply the new mask called plasmonic-photonic mask for precise analysis of the captured images. In the early stage of the work, a phantom model is employed and the operation of the system is realized. It is shown that the image processing toolbox is safely matched with the device. It should be noted that for the in-vivo imaging, the device should be completed and equipped with a high accuracy charge coupled device (CCD) and laser.
Citation - WoS: 6
Citation - Scopus: 7
Bit error rate analysis of MISO FSO systems
(Taylor & Francis Ltd, 2016) Gokce, Muhsin Caner; Gökçe, Muhsin Caner; Baykal, Yahya; Uysal, Murat; 28643; 7812; 124615; Elektronik ve Haberleşme Mühendisliği
Multiple-input single-output (MISO) systems are employed in free space optical (FSO) links to mitigate the degrading effects of atmospheric turbulence. In this paper, we consider a MISO FSO system with practical transmitter and receiver configuration that consists of radial laser array with Gaussian beams and a Gaussian receiver aperture function. We have employed our previously derived formulation of the power scintillation in which Huygens-Fresnel principle was employed. Therefore, we choose system parameters within the range of validity of the wave structure functions. Using the on-off keying modulation and the log-normal probability distribution function, we quantify the average bit error rate (< BER >) of laser array beams in weak turbulence. It is observed that the radial array beams at the transmitter are more advantageous than the single Gaussian beam. However, increasing the number of array beamlets to more than three seems to have negligible effects on < BER >. It is further observed that < BER > decreases when the source size, the ring radius and the receiver aperture radius increase.
Citation - Scopus: 0
Calculation of the Halfwidth and the Activation Energy for the Soft Raman Modes in the Brominated Compounds of Tris-Sarcosine Calcium Chloride
(Walailak University, 2022) Kiraci, A.; Kiracı, Ali; 42475; Ortak Dersler Bölümü
This 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. © 2022, Walailak University. All rights reserved.
Citation - WoS: 1
Citation - Scopus: 3
Comparative Analysis of Novel Long Life Routing Methods In Mobile Networks
(Ieee, 2010) Preveze, Barbaros; Preveze, Barbaros; Safak, Aysel; 17573; Elektrik-Elektronik Mühendisliği
In this study we propose two novel ABR extended Long Life Routing Methods called Alternative enhancement for Enhanced Associativity Based Routing (AEABR) and Associativity Tick Averaged ABR (ATAABR) methods which are also modifications of Associativity Based Routing (ABR). Comparison of these associativity based long Life routing algorithms in Mobile Networks are done for route speeds, life times and outage times Since ABR at most focuses on power strength, it will be preferable in most systems to establish long life routes from source to destination considering the power constraints. It is shown in this paper that, the novel algorithms that we propose provide better life time, link speeds and outage time results than EABR (Enhanced Associativity Based Routing) method and other relay selection algorithms taken into consideration in this work. It's illustrated that the performance of EABR method, is really better than other relay selection algorithms for number of Route reconstructions (RRC) or relay changes and Connected Status Percentage (CSP). On the other hand it has also been illustrated that AEABR and ATAABR improve the connection stability of EABR by keeping the connection outage time at lower levels where ATAABR require less modification on algorithm and needs less computation time. AEABR improves either connection outage times or number of RRC. During this analysis message overhead and bandwidth wastage of each algorithm is also investigated. The proposed algorithms can be used in designing a unicast mobile network having power constraints to provide longer path life and lower number of route reconstructions.
Citation - Scopus: 4
Comparing control performances of mrac and pid applied on a brushless dc motor
(International Organization on 'Technical and Physical Problems of Engineering', 2020) Ciba, S.; İskender, İres; Iskender, I.; Ariani, H.A.; 133746; Elektrik-Elektronik Mühendisliği
Brushless DC motors are powered by a DC electric source and are used widely used in appliance, automotive, aerospace, medical and industrial equipment due to their compact size and light weight. Parallel to improvements in semiconductor industries the operating frequency of semiconductor switches and microcontrollers are getting improve and this provides conditions to use different algorithms in motor control. In this study the reference model adaptive control of a DC brushless motor will be studied. Brushless DC motors have some advantages such as long working life, high efficiency, and low maintenance requirements; however their control is a bit complicated. For this reason, there have been published many studies in relative with speed control of brushless DC motors. Classical or modern control methods can be used for this purpose. In this study, BLDC motor is controlled with firstly classical PID controller and secondly model reference adaptive control (MRAC) based on MIT law method and the results are compared. © 2020, International Organization on 'Technical and Physical Problems of Engineering'. All rights reserved.
Citation - WoS: 5
Citation - Scopus: 7
Comparison of single channel indices for U-Net based segmentation of vegetation in satellite images
(Spie-int Soc Optical Engineering, 2020) Ulku, Irem; Barmpoutis, Panagiotis; Stathaki, Tania; Akagunduz, Erdem; 233834
Hyper-spectral satellite imagery, consisting of multiple visible or infrared bands, is extremely dense and weighty for deep operations. Regarding problems related to vegetation as, more specifically, tree segmentation, it is difficult to train deep architectures due to lack of large-scale satellite imagery. In this paper, we compare the success of different single channel indices, which are constructed from multiple bands, for the purpose of tree segmentation in a deep convolutional neural network ( CNN) architecture. The utilized indices are either hand-crafted such as excess green index (ExG) and normalized difference vegetation index (NDVI) or reconstructed from the visible bands using feature space transformation methods such as principle component analysis (PCA). For comparison, these features are fed to an identical CNN architecture, which is a standard U-Net-based symmetric encoder-decoder design with hierarchical skip connections and the segmentation success for each single index is recorded. Experimental results show that single bands, which are constructed from the vegetation indices and space transformations, can achieve similar segmentation performances as compared to that of the original multi-channel case.

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