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: 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.
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 - 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 - 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 - WoS: 6
Citation - Scopus: 7
Coreloss Estimation via Long Short-Term Memory Model (LSTM) of Dry-Type Transformer based on FEA
(Ieee, 2021) Kul, Seda; İskender, İres; Yildiz, Berat; Tamyurek, Bunyamin; Iskender, Ires; 133746; Elektrik-Elektronik Mühendisliği
Accurate estimation of losses is very important in transformer designs for energy systems. Therefore, in this study, a long short-term memory model (LSTM) was performed to predict the core loss of three-phase dry-type transformers based on Finite Element Analysis (FEA) analysis. Since, in ordinary multilayer networks, learning problems occur when the gradient value gets too small during backpropagation. LSTM, on the other hand, can store information better thanks to its extra layers that communicate. Thus, the learning process takes place more efficiently. The analysis and estimation processes were performed using a primary number of turns, excitation voltage, and three different cross-section area parameters. 486 data randomly selected from 506 data obtained by ANSYS/MAXWELL in the training of the LSTM model were used. The remaining 20 data were used in the testing process to measure system performance. The error obtained by the validation test is 0.15. It is very close to the simulated value, thus LSTM can be used as a reliable estimation method during the design stage.
Citation - Scopus: 0
Design and Modeling Interdigitated Capacitor - Spiral Inductor Resonator for Optical Pressure Sensor
(Institute of Electrical and Electronics Engineers Inc., 2021) Demirel, M.; Duyguluer, G.; Öztürk, M.; Salmanogli, A.; Gecim, H.S.; 182579
In this study, an optical pressure sensor is designed to sense a force. To achieve that, an interdigitated capacitor connected to a spiral inductor that oscillates at GHz region is proposed to be designed. To sense a force with very low amplitude, some different materials are applied as a dielectric material between the layers of the interdigitated capacitor. Thus, by applying the force, the circuit's capacitance is changed due to the displacement of the selected dielectric. This leads to change of the circuit's scattering parameters which lets to sense the lowest scale of the pressure possible. For simulation, the circuit is designed in COMSOL, theoretically studied the scattering parameters and the effect of the force on the circuit characteristic and finally, Advanced Design System is used to optimize the parameters for this specific aim. © 2021 Chamber of Turkish Electrical Engineers.
Citation - Scopus: 0
Design and Modeling of Very Narrow Band-pass Radio Frequency Filter for Optical Pressure Sensor
(Institute of Electrical and Electronics Engineers Inc., 2021) Ispak, T.S.; Basarancr, G.; Ceylan, S.; Salmanogli, A.; Gecim, H.S.; 182579
In this study, an optical pressure sensor is designed to sense a force on the scale of 100 nN. For this purpose, a very narrow radio frequency band-pass filter is designed and modeled to detect the optical pressure force. The center frequency of the filter is fixed in L-band. Thus, by applying an external force, the circuit's characteristics such as scattering parameters and the center frequency of the filter is changed. That is the method particularly employed to sense a very low scale optical pressure. In this study, the open-stub technique is used to design the radio frequency filter and results are compared with the lumped element-based circuit models. Also, the circuit design is simulated in COMSOL Multiphysics, and the scattering parameters are studied. Finally, the circuit is optimized for the specific aim using Advanced Design System software. © 2021 Chamber of Turkish Electrical Engineers.
Dynamic Optımızatıon of Image Brıgthness Level With Optimal Gamma Value Assessment (OGVA) Method
(2020) Preveze, Barbaros; Preveze, Barbaros; 17573; Elektrik-Elektronik Mühendisliği
Bu çalışmada, önerilen Optimum Gama Değeri Ataması (OGVA) yöntemi ile istenmeyen ışık seviyeleri içeren görüntülerde görüntü ışık seviyesinin dinamik olarak optimize edilmesi amaçlanmıştır. Bu amaçla ışığın yetersizliğinden dolayı görülemeyen karanlık görüntüler aydınlatılırken, parlak görüntülerin ise anlık olarak uygulanan en iyi gama düzeltme değeri kullanılarak dinamik olarak karartılması amaçlanmaktadır. Herhangi bir ek donanım gerektirmeden sadece yazılım olarak uygulanacak olan bu yeni yöntemin, çok küçük hesaplama maliyeti ile farklı ışık seviyeleri için bile tatmin edici sonuçlar verdiği gösterilmiştir.
Ear semantic segmentation in natural images with Tversky loss function supported DeepLabv3+ convolutional neural network
(2022) İnan, Tolga; Kacar, Umit; Inan, Tolga; Elektrik-Elektronik Mühendisliği
Semantic segmentation is a fundamental problem for computer vision. On the other hand, for studies in the field of biometrics, semantic segmentation is gaining more importance. Many successful biometric recognition systems require a high- performance semantic segmentation algorithm. In this study, we present an effective ear segmentation technique in natural images. A convolutional neural network is trained for pixel-based ear segmentation. DeepLab v3+ network structure, with ResNet-18 as the backbone and Tversky lost function layer as the last layer, has been trained with natural and uncontrolled images. We perform the proposed network training using only the 750 images in the Annotated Web Ears (AWE) training set. The corresponding tests are performed on the AWE Test Set, University of Ljubljana Test Set, and the Collection A of In-The-Wild dataset. For the Annotated Web Ears (AWE) dataset, intersection over union (IoU) is measured as 86.3% for the AWE database. To the best of our knowledge, this is the highest performance achieved among the algorithms tested on the AWE test set.
Citation - Scopus: 3
Effects of ant colony and fastest path routing algorithms on performance improvement of novel cognitive methods
(2010) Preveze, B.; Preveze, Barbaros; Safak, A.; 17573; Elektrik-Elektronik Mühendisliği
This paper demonstrates the usage of novel cognitive methods that improve the throughput of a WIMAX network by minimizing packet loss. The effects of the ant colony and fastest path routing algorithms on the throughput are investigated. A combination of Time Division Multiple Access (TDMA) and Orthogonal Frequency Division Multiple Access (OFDMA) spectrum sharing techniques is used. Data packet loss rate is minimized for real-time voice and video packet transmissions. A unicast mobile multimedia network with improved system throughput is provided with both routing methods, even for a small node count. © 2010 IEEE.

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