Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/11
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Conference Object Citation - WoS: 1Citation - Scopus: 1Görgül kip ayrıştırması kullanılarak optik faz kırınımında hassasiyet iyileştirilmesi(IEEE, 2023) Ataç, Enes; Dinleyici, Mehmet SalihPhase diffraction is a potent property used in transparent dielectric film characterization. The measured diffraction pattern on the camera is evaluated by matching numerically computed diffraction patterns to determine the optical properties of the ultra-thin films (refractive index, thickness, etc.). However, the obtained diffraction data is not only a nonlinear and non-stationary signal but also exhibits micron-scale variations, thus limiting the measurement accuracy. Therefore, it is challenging to identify shifts in minima and deviations in amplitude on diffraction data to extract information about the optical properties of phase objects. In this study, it is aimed to improve the thickness sensitivity of the system by applying Empirical Mode Decomposition (EMD) to plane wave-based near-field phase diffraction data. Since EMD is very sensitive to abrupt changes in the signal due to the spatial frequency components, the nanoscale variations in the film thickness become more observable and detectable. Experimental outputs and numerical simulations show that the decomposition increases the thickness sensitivity comparing the classical matching technique.Conference Object Citation - Scopus: 2Parkinson hastalığı sınıflandırmasına yönelik ivmeölçer tabanlı zamanlama analizi(IEEE, 2023) Karaçalı, Bilge; Onay, FatihParkinson's disease is a neurodegenerative disorder caused by dopamine deficiency in the basal ganglia, resulting in cognitive and motor impairments. In this study, accelerometer signals were used to estimate the delay time between the command to start pedaling and the actual movement onset in three groups: healthy individuals (n=13), Parkinson's disease patients (n=13), and patients with freezing of gait symptoms (n=13). Features were extracted from the delay time distributions for each participant and subjected to a triple classification. Linear support vector machine achieved a classification accuracy of 69.2% for all participants. Notably, the average time to start pedaling was found to be significantly different among the three groups, and accelerometer-based timing analysis could be used as a diagnostic tool to assist clinical tests.Conference Object Dalgacık gürültü giderme yöntemiyle mikrodalga bileşen karakterizasyonunun iyileştirilmesi(IEEE, 2023) Karatay, Anıl; Olcay, Bilal Orkan; Yaman, FatihIn this study, an efficient approach is presented to improve the characterization of various microwave components commonly used in communication and radar applications, such as antennas and power dividers. The components were initially simulated and then fabricated using the Computer Simulation Technology (CST) software. Vector Network Analyzer (VNA) measurements of the fabricated components were performed using a low-cost but noisy coaxial cable, and the measurement results were processed using a wavelet-based noise reduction method. For comparison purposes, the Haar and Daubechies-4 (DB4) wavelet functions were applied separately, and the results were examined. It was observed that the correlation and root mean square error between the ideal and measurement results improved in a positive direction with the noise reduction application. This approach provides significant cost and labor advantages, particularly when expensive elements such as gold and silver are used in coaxial cables that are physically free from noise. The experimental and numerical results show good agreement between the ideal simulation results and the filtered measurement results.Conference Object Algıda gecikme ve kısa-ömürlü senkronizasyon temelli yeni bir hayali motor aktivite tanıma yaklaşımı(IEEE, 2023) Olcay, B. Orkan; Karaçalı, BilgeThis study proposes a novel approach for investigating a brain-computer interface that considers the temporal organization of brain activity, explicitly accounting for perception latency. To this end, we aligned the onset of task periods with the concurrence of left parietal and parieto-occipital electrodes to obtain the timings of perception latencies. Then, activity-specific synchronization timings between channel pairs were calculated using the time-aligned task periods. The perception latency and activity-specific synchronization timings were subsequently used for feature extraction and classification. The proposed approach achieved significantly better performance when comparing the proposed approach with the method that did not account for the perception latencyConference Object Citation - Scopus: 1Diziden Diziye Modeli ve MIDI Müzik Veri Tabanı Kullanımıyla Gerçekçi Bir Davul Eşliği Üreteci(IEEE, 2022) Akyuz, Yavuz Batuhan; Gumustekin, SevketIn this work, artificial intelligence reinterpretation and/or addition of drum parts for musical pieces supplied in Musical Instruments Digital Interface (MIDI) format, have been carried out. To achieve this, Sequence-to-Sequence learning method and Encoder-Decoder Long Short-Term Memory (LSTM) artificial neural network model have been used. In order to improve training of this neural network, teacher forcing method was utilized. In the generation of new drum parts, the quality and the originality of the samples were improved by using temperature sampling. Our proposed method produces high quality drum accompaniments with adjustable complexity.Conference Object Üç Tümyönlü Kamera Kullanarak Stereoskopik. Video Karelerinin Gerçek Zamanlı Yapımı(IEEE, 2022) Cali, Mehmet; Gomustekin, SevketThere are many studies about acquisition of monoscopic and stereoscopic panorama in the literature. Since obtaining motion parallax accurately without having distortions is a very challenging problem, especially 360-degree stereoscopic image and video capturing has become a prevalent research topic. However, studies in this topic have focused on costly systems with many cameras and high processing power demand. In this study, which presents an efficient solution in terms of processing power and cost, stereoscopic frames are processed in real time using three consumer grade 360-degree cameras whose outputs are sampled according to view orientation. Besides, a method is developed to eliminate the distortions around the borders of the field of view with the help of blending with selected auxiliary camera frames.Conference Object Ampute Elektromiyografi Sinyallerinin Evrişimli Sinir Ağları Kullanılarak Sınıflandırılması(IEEE, 2020) Onay, Fatih; Mert, AhmetThe classification of EMG signals for the amputees is important to develop a powered-prosthetic that is capable of replacing with lost limbs. The EMG signals collected from residual limbs reduce the classification accuracy due to muscle movements that cannot be realized properly. In this study, classification performance is aimed to be increased by combining CNN with root mean square (RMS) and waveform length (WL) that are used in analysis of EMG signals successfully. The features such as RMS and WL extracted from EMG signals for the classification of six hand movements at the low, medium, and high force levels were applied to CNN input, and classification results were compared with nearest neighbour and linear discriminant analysis.Conference Object Citation - WoS: 2Citation - Scopus: 5Ardışık Etkinleştirilen Çoklu Derinlik Kameraları Kullanımıyla 3b Nesne Geriçatımı(IEEE, 2020) Tunçer, Esra; Gümüştekin, ŞevketBu çalışmada, bir objenin 3-boyutlu yapısının tümüyle elde edilmesi amacıyla objenin çevresine 4 adet derinlik kamerası (Kinect v1) yerleştirilmiştir. Çoklu Kinect kullanımında karşılaşılan bilgisayar bant genişliği ve girişim problemleri eklenti USB 2.0 kontrolcüler ve elektronik kontrollü objektif kapakları ile çözülmüştür. Alınan görüntülerin birleştirilmesi için kalibrasyon işlemi kızılötesi görüntüler üzerinde uygulanmıştır. Eşleşme problemleri Döngülü En Yakın Nokta metoduyla giderilmiş ve %3.41 hata oranına sahip eşleşme elde edilmiştir. Farklı geometrik özelliklere sahip nesnelerin 3B modellenmesi için eşleştirilen nokta bulutlarına Meshlab yazılımı aracılığıyla Poisson Yüzey Geriçatımı işlemi uygulanmıştırConference Object Citation - Scopus: 1Yüksek İrtifa Platform İstasyonları için Korelasyon Matrisinin Yaklaşımı(Institute of Electrical and Electronics Engineers Inc., 2021) Cengiz, Aybüke; Tedik Başaran, Semiha; Karabulut Kurt, Güneş; Özbek, Berna; Yanıkömeroğlu, HalimA High Altitude Platform Station (HAPS) is a new and promising technology with different uses like wireless communication services, traffic monitoring, navigation applications and Internet of Things (IoT) applications. Since it is positioned much higher than ground-level users, line-of-sight (LOS) is more common in HAPS systems. Especially in HAPS systems that include multiple antennas, the effect of correlation between antennas is an important factor limiting the performance. The effect of correlation is strongly influenced by the spacing between the antenna elements and environmental factors. This effect can be reduced by the effect of rich scattering environment in terrestrial Multi-Input/Multi-Output (MIMO) systems, yet this observation is not applicable to HAPS systems. In this study, a tight bound expression for the correlation matrix which does not have an expression in closed form and has a significant place in the performance of HAPS systems has been obtained. Comprehensive numerical values have been obtained under different system parameters to demonstrate the convergence performance of the approximate expression to the real value, and the results have been compared. © 2021 IEEE.Conference Object Cbr ve Vbr Kodlanmış Ölçeklenir Videolar ile Uyarlanabilir İletimin Karşılaştırmalı Analizi(IEEE, 2021) Cali, Mehmet; Ozbek, NukhetHaving an influence on the effective utilization of network resources, optimum video streaming in various network conditions have a significant role. Therefore, optimization studies on DASH receives considereable attention from the researchers. Although most of these studies focus on developing adaptation algorithm in the client side, the effect of decisions made during video encoding on the perceived quality cannot be underestimated. In this study, the effect of encoding mode selection on the perceived quality for scalable video coding is investigated. Streaming of videos which are encoded in CBR and VBR modes are tested with extensive network conditions by implementing three different adaptation algorithm. It is observed that VBR encoding has superior performance with a considerable margin in terms of both video stall duration and video quality switching frequency.