Elektrik-Elektronik Mühendisliği / Electrical - Electronics Engineering
Recent Submissions
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NOMA-based radio resource allocation for machine type communications in 5G and beyond cellular networks 5G ve ötesi hücresel ağlarda makine tipi iletişim için NOMA tabanlı radyo kaynak atama
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Publisher and Date:(Kadir Has Üniversitesi, 2021)Makineden makineye iletişimdeki hızlı artış, hücresel ağların tasarımında zorluklar getiriyor. Yetersiz radyo kaynaklarına sahip çok sayıda makine tipi iletişim cihazının hizmet kalitesi gereksinimlerini karşılamanın zorluğu ortaya çıktı. Bu tezin temel amacı, 5G ve hücresel ağların ötesinde, dikgen olmayan çoklu erişim tabanlı makineler arası iletişimleri için minimum bant genişliği kaynak tahsisi problemini araştırmaktır. Problemi hızlı ve verimli bir şekilde çözmek için NOMA ve MTC trafiğinin ...
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The optical and electrical characteristics of ZnO / MoS2 transparent oxide composite films / ZnO / MoS2 şeffaf oksi̇ti̇n opti̇k ve elektri̇ksel özelli̇kleri̇kompozi̇t fi̇lmler
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Publisher and Date:(Kadir Has Üniversitesi, 2021)Optoelektronikte saydam iletken oksit kullanımı, verimliliği düşürmeden veya maliyeti artırmadan esneklik, dayanıklılık ve taşınabilirlik becerisinin elde edildiği bir devrim yaratmaktadır. ZnO / MoS2 saydam iletken kompozit filmi basit bir süreç oluşu ve düşük maliyeti nedeniyle en önemli yöntem olarak kabul edilen sol-jel yöntemi ile üretilmiştir. ZnO / MoS2'nin kristal yapı özellikleri, X-Işını kırınım modeli (XRD) ile karakterize edilmiştir. XRD spektroskopisi ile, farklı miktarlarda MoS2 ...
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Autonomous vehicle control using reinforcement learning / Otonom bir aracın pekiştirmeli öğrenme ile kontrolü
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Publisher and Date:(Kadir Has Üniversitesi, 2020)Otonom araçlar, yapay zekanın uygulandığı önemli bir araştırma konusu haline geldi. Araştırmalar yoğunlaştıkça yapay zeka algoritmalarının farklı alanlardaki uygulamaları ile insan müdahalesi, zaman, enerji, kontrol gibi faktörlerin değişimine bağlı olarak sistemlerin çalışma mekanizmalarının ve hedeflerine varış doğrultularının daha optimal bir sonuca ulaştırdığı görülmektedir. Derin öğrenme ve makine öğrenme algoritmalarının farklı durum ve koşullarda avantaj ve dezavantajları olduğu görülmüştür. ...
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Air quality prediction using a hybrid deep learning architecture / Hibrit derin öğrenme mimarisi kullanarak hava kalitesi tahmini
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Publisher and Date:(Kadir Has Üniversitesi, 2020)Hava kirliliği tahmini, çevresel izleme verilerindeki değişkenlerle ve bu değişkenler arasındaki karmaşık ilişkinin modellenmesiyle ilgilidir. Tezin amacı, gerçek sensör verilerini kullanarak hava kirliliğinin tahmini için denetimli bir model geliştirmek ve modeli şehirler arasında aktarmaktır. Mekansal-zamansal bir ilişki kullanarak birden çok konumdaki hava kirleticilerinin konsantrasyonunu tahmin etmek için bir CNN+LSTM derin sinir ağı modeli geliştirildi. 2B ve 3B girdi yapıları tanımlanır: ...
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Power transfer networks at RF frequencies "New design procedures with implementation roadmap"
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Publisher and Date:(IEEE, 2006)The purpose of this work is to provide the necessary background to design wide-band power transfer two-ports, or so-called broadband matching networks, at radio frequencies for wireless communication systems. The importance of the topic stems from the recent advances in the conceptual design and manufacturing technologies of the next-generation wireless and mobile communication systems, which will operate over ultra-wide frequency bands. In fact, for all communication systems, construction of ...
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Analysis and Optimization of Matching Networks-II Getting Started with Microwave Office
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Publisher and Date:(Springer-Verlag Berlin, 2008)
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Analysis and Optimization of Matching Networks-I Getting Started with ADS
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Publisher and Date:(Springer-Verlag Berlin, 2008)
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Design and Implementation of a Cellular Neural Network Based Oscillator Circuit
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Publisher and Date:(World Scientific and Engineering Acad and Soc, 2009)In this paper, a novel inductorless oscillator circuit with negative feedbacks, based on a simple version of a "Cellular Neural Network" (CNN) called "CNN with an Opposite Sign Template" (CNN-OST) is designed and implemented. The system is capable of generating quasi-sine oscillations with tuneable amplitude and frequency which can't be provided at the same time in the conventional oscillator circuits.
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Caching algorithm implementation for edge computing in IoT network
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Publisher and Date:(Kadir Has University, 2020)The developing IoT concept brings new challenges to the service providers. The architecture of the networks changes to satisfy the needs arising by the large number of connected devices. Edge computing is the new architectural solution that will be used in the IoT networks. This architecture is more dynamic than the cloud computing network where the data can be quickly processed in the different layers of the network without going to the cloud. This will remove the problems faced by cloud computing: ...
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Optimal On-Off Transmission Schemes for Full Duplex Wireless Powered Communication Networks
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Publisher and Date:(IEEE, 2020)In this paper, we consider a full duplex wireless powered communication network where multiple users with radio frequency energy harvesting capability communicate to an energy broadcasting hybrid access point. We investigate the minimum length scheduling and sum throughput maximization problems considering on-off transmission scheme in which users either transmit at a constant power or remain silent. For minimum length scheduling problem, we propose a polynomial-time optimal scheduling algorithm. ...
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Sparse Channel Estimation with Clipping Noise in DCO-OFDM Based VLC Systems
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Publisher and Date:(IEEE, 2020)In this paper a new computationally efficient and high performance channel estimation algorithm is proposed for DC-biased optical OFDM (DCO-OFDM) systems in indoor visible light communications (VLC) in the presence of a clipping noise. The sparse structure of the channel is taken into consideration in the channel estimation algorithm. The algorithm has an iterative structure and aims at reducing the effect of the clipping noise, inevitably generated by the DCO-OFDM systems. In te algorithm, the ...
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Smart Stethoscope
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Publisher and Date:(IEEE, 2020)In this study, a device named smart stethoscope that uses digital sensor technology for sound capture, active acoustics for noise cancellation and artificial intelligence (AI) for diagnosis of heart and lung diseases is developed to help the health workers to make accurate diagnoses. Furthermore, the respiratory diseases are classified by using Deep Learning and Long Short-Term Memory (LSTM) techniques whereas the probability of these diseases are obtained.
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Complete density calculations of q-state Potts and clock models: Reentrance of interface densities under symmetry breaking
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Publisher and Date:(Amer Physical Soc, 2020)All local bond-state densities are calculated for q-state Potts and clock models in three spatial dimensions, d = 3. The calculations are done by an exact renormalization group on a hierarchical lattice, including the density recursion relations, and simultaneously are the Migdal-Kadanoff approximation for the cubic lattice. Reentrant behavior is found in the interface densities under symmetry breaking, in the sense that upon lowering the temperature, the value of the density first increases and ...
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Hybrid MEMS-Based molecular communication system
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Publisher and Date:(Institute of Electrical and Electronics Engineers Inc., 2019)In this paper, we consider a molecular communication link integrated in a micro-electro mechanical system (MEMS) based environment. We apply acoustic tweezing techniques to the molecular communication system to increase communication reliability. We use finite element methods to simulate this hybrid system. By deriving the symbol error rate as the performance metric, we show that the proposed system facilitates reliable communication in the presence of fluid flow and its performance is robust ...
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Channel Modeling for Visible Light Communications
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Publisher and Date:(Springer-Verlag Berlin, 2016)In this chapter, we present a novel and realistic channel modeling approach for visible light communications that overcomes the limitations of previous works. In our work, we consider wavelength dependency, effect of realistic light sources as well as different types of reflections such as specular and mixed cases of diffuse and specular. We use nonsequential ray tracing algorithms to calculate the detected power and path lengths from source to detector for each ray. These are then processed to ...
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IEEE 802.15.7r1 Reference Channel Models for Visible Light Communications
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Publisher and Date:(IEEE-Inst Electrical Electronics Engineers Inc, 2017)The IEEE has established the standardization group 802.15.7r1 "Short Range Optical Wireless Communications", which is currently in the process of developing a standard for visible light communication (VLC). As with any other communication system, realistic channel models are of critical importance for VLC system design, performance evaluation, and testing. This article presents the reference channel models that were endorsed by the IEEE 802.15.7r1 Task Group for evaluation of VLC system proposals. ...
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Busy Tone Based Power Control for Coordination of IFFY 802.11af and 802.22 System
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Publisher and Date:(IEEE, 2017)In this paper, a new power control algorithm based on busy tone approach has been proposed for the coordination of IEEE 802.22 and IEEE 802.11af systems in TV white space. Different from the earlier studies, in addition to both 802.11af access point and clients listening to the busy tone, they also adjust their communication power according to the location information and use hopping for communication, if needed Acccordingly, interference caused to 802.22 systems has been reduced while the 802.11af ...
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Design of Phase Shifters with Ladder Stubs Via Real Frequency Technique
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Publisher and Date:(World Scientific, 2020)Generally at high frequencies, lumped-elements are not preferred because of their limited range of values. Therefore, in this work, a kind of phase shifter formed with ladder stubs is studied and a new approach to design phase shifter's low pass and high pass sections which are composed of series or shunt connected open-ended or short-ended stubs is proposed. In the approach, since the main focus is to form low pass and high pass two-port sections, switching process is not considered. First, the ...
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Mixed Element Networks With Series Capacitors Separated By Unit Elements
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Publisher and Date:(World Scientific, 2020)In this work, high-pass mixed-element networks with series capacitors separated by unit elements are analyzed. First, the description of the networks via two frequency variables is given. Then, explicit coefficient relations for the descriptive polynomials are derived in terms of the single-variable boundary polynomial coefficients. Finally, the derived relations are used to design a high-pass mixed-element matching network. The series capacitors can be converted to short-ended stubs by means of ...
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Physical-layer security in visible light communications
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Publisher and Date:(Institute of Electrical and Electronics Engineers Inc., 2020)Optical wireless communications (OWC) and its potential to solve physical layer security (PLS) issues are becoming important research areas in 6G communications systems. In this paper, an overview of PLS in visible light communications (VLC), is presented. Then, two new PLS techniques based on generalized space shift keying (GSSK) modulation with spatial constellation design (SCD) and non-orthogonal multiple access (NOMA) cooperative relaying are introduced. In the first technique, the PLS of the ...
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