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Articles 1 - 20 of 20
Full-Text Articles in Engineering
Designing Framework For The Computer Aided Design Of Silicon Carbide Jfet Circuits In Bleo Environments, Venkata Vinay Naidugari
Designing Framework For The Computer Aided Design Of Silicon Carbide Jfet Circuits In Bleo Environments, Venkata Vinay Naidugari
Electronic Theses and Dissertations
Abstract: circuit design and testing are two essential processes to synthesis of an efficient and reliable circuit. Real-time testing of a circuit through circuit fabrication and development is an expensive and a risky procedure whereas testing the circuit by modelling and simulating is more efficient and inexpensive. Silicon-based semiconductors are the basic components of any modern day electronic devices, and their usage has dominated the marketplace. But these conventional cmos devices cannot exist in an environment consisting of harsh radiation, high temperature and many other environmental conditions, such as venus or mars. However, 6h-sic jfets, which are basic logic gate …
Maximizing Cache Value For Distributing Content Via Small Cells In 5g, Ibrahim Khalaf Freewan
Maximizing Cache Value For Distributing Content Via Small Cells In 5g, Ibrahim Khalaf Freewan
Electronic Theses and Dissertations
The objective of this thesis is to develop an algorithm for distributing content at small cells in 5G, wherein small cells (SCs) are set up instead of macro cells to serve mobile users. Users may simultaneously access between one and some maximum number of SCs, the actual number of SCs being drawn from a distribution. The source library is located away from these sites, and it stores files as a collection of RaptorQ-encoded symbols. By using RaptorQ symbols a very large number of distinct encoding symbols can be generated and a collection of received encoded symbols slightly larger than the …
Performance Evaluation And Improvement Of Wireless Amplify-And-Forward Cooperative-Based Systems Under Nodes Mobility And Imperfect Csi Estimation Impacts, Yazid Khattabi
Electronic Theses and Dissertations
Cooperative communication techniques have been introduced in wireless networks to achieve spacial diversity-gain via the readiness of multiple users (via relays) to assist a source forwarding its data to a final destination. Cooperative communication techniques have shown their capability in improving system reliability and extending coverage area, and hence, it is believable that they will act as a promising technology for the coming fifth-generation (5G). Nevertheless, most existing work reported in literature on performance studies of wireless cooperative-based systems are based on the assumptions that the multipath fading channels among systems cooperating nodes are quasi-static (i.e., fading channels coefficients are …
Reduction Of Mutual Coupling In Antenna Technology Using Elliptically Shaped Metasurfaces, Gabriel Moreno
Reduction Of Mutual Coupling In Antenna Technology Using Elliptically Shaped Metasurfaces, Gabriel Moreno
Electronic Theses and Dissertations
This thesis is devoted to the use of metasurfaces for the goals of the reduction of mutual coupling between closely spaced antennas and the increase of antenna bandwidth. This is done first using a graphene monolayer as a cloak to decrease mutual coupling and restore radiation patterns for closely spaced antennas at THz frequencies. The introduction of the graphene monolayer was also extensively studied in regards to the effect on the radiation properties of the antennas. The use of metasurfaces also has other applications, in particular with the bandwidth of antennas, where an anisotropic metasurface can be used to drastically …
Localization Of Sensors In Presence Of Fading And Mobility, Hamzeh Hussain Omari
Localization Of Sensors In Presence Of Fading And Mobility, Hamzeh Hussain Omari
Electronic Theses and Dissertations
The objective of this dissertation is to estimate the location of a sensor through analysis of signal strengths of messages received from a collection of mobile anchors. In particular, a sensor node determines its location from distance measurements to mobile anchors of known locations. We take into account the uncertainty and fluctuation of the RSS as a result of fading and take into account the decay of the RSS which is proportional to the transmitter-receiver distance power raised to the PLE. The objective is to characterize the channel in order to derive accurate distance estimates from RSS measurements and then …
Divergence And Bayes Error Based Soft Decision For Decentralized Signal Detection Of Correlated Sensor Data, Roopa Shree Rajanna
Divergence And Bayes Error Based Soft Decision For Decentralized Signal Detection Of Correlated Sensor Data, Roopa Shree Rajanna
Electronic Theses and Dissertations
No abstract provided.
Elliptical Metasurfaces For Cloaking And Antenna Applications At Microwave And Terahertz Frequencies, Hossein Mehrpourbernety
Elliptical Metasurfaces For Cloaking And Antenna Applications At Microwave And Terahertz Frequencies, Hossein Mehrpourbernety
Electronic Theses and Dissertations
No abstract provided.
Implementation Of A Raptorq-Based Protocol For Peer To Peer Network, Yuzhu Bai
Implementation Of A Raptorq-Based Protocol For Peer To Peer Network, Yuzhu Bai
Electronic Theses and Dissertations
The object of this thesis is to develop and test a Ruby based implementation of the RaptorQP2P protocol. The RaptorQP2P protocol is a novel peer-to-peer protocol based on RaptorQ forward error correction. This protocol facilitates delivery of a single file to a large number of peers. It applies two levels of RaptorQ encoding to the source file before packet transmission. Download completion time using RaptorQP2P was found to be significantly improved comparing to BitTorrent. We developed a Ruby interface to the Qualcomm proprietary RaptorQ software development kit library. Then we achieved the two levels of RaptorQ encoding and decoding with …
Mcmc- Based Optimization And Application, Xiaobin Wu
Mcmc- Based Optimization And Application, Xiaobin Wu
Electronic Theses and Dissertations
In the thesis, we study the theory of Markov Chain Monte Carlo (MCMC) and its application in statistical optimization. The MCMC method is a class of evolutionary algorithms for generating samples from given probability distributions. In the thesis, we first focus on the methods of slice sampling and simulated annealing. While slice sampling has a merit to generate samples based on the underlying distribution with adjustable step size, simulated annealing can facilitate samples to jump out of local optima and converge quickly to the global optimum. With this MCMC method, we then solve two practical optimization problems. The first problem …
Optimized Image Compressed Sensing And Transmission Through Wireless Channels, Saheed Olanigan
Optimized Image Compressed Sensing And Transmission Through Wireless Channels, Saheed Olanigan
Electronic Theses and Dissertations
This thesis examines the robust behavior of quantized compressed sensing measurements during transmission through an additive white gaussian noise wireless channel. The poor rate-distortion performance that accompanies compressed sensing after applying quantization has led to several works in quantized compressed sensing. However, most of these works have less consideration of the effect of transmission channel on the resulting bit stream of the quantized compressed sensing measurements. For an additive white gaussian noise wireless channel model, the quantizer and bit energy signal-to-noise ratio determines the degree of the channel effect. This thesis explores the effect of quantization and channel noise during …
Cross-Layer Capacity Optimization In Ofdma Systems: Wimax And Lte, Bimal Paudel
Cross-Layer Capacity Optimization In Ofdma Systems: Wimax And Lte, Bimal Paudel
Electronic Theses and Dissertations
Given the broad range of applications supported, high data rate required and low latency promised; dynamic radio resource management is becoming vital for newly emerging air interface technologies such as wireless interoperability for microwave access (Wimax) and long term evolution (lte) adopted by international standards. This thesis considers orthogonal frequency division multiple access (ofdma) system, which has been implemented in both Wimax and lte technologies as their air interface multiple access mechanism. A framework for optimized resource allocation with quality of service (qos) support that aims to balance between service provider's revenue and subscriber's satisfaction is proposed. A cross-layer optimization …
Adaptive Relay-Selection In Decode-And-Forward Cooperative Systems, Adham Ahmed Hagag
Adaptive Relay-Selection In Decode-And-Forward Cooperative Systems, Adham Ahmed Hagag
Electronic Theses and Dissertations
In the past few years adaptive decode-and-forward cooperative diversity systems have been studied intensively in literature. Many schemes and protocols have been proposed to enhance the performance of the cooperative systems while trying to alleviate its drawbacks. One of the recent schemes that had been shown to give high improvements in performance is the best-relay selection scheme. In the best-relay selection scheme only one relaying nodes among the relays available in the system is selected to forward the source's message to the destination. The best relay is selected as the relay node that can achieve the highest end-to-end signal-to-noise ratio …
Rss Based Localization In A Rayleigh Fading Environment, Rojina Adhikary
Rss Based Localization In A Rayleigh Fading Environment, Rojina Adhikary
Electronic Theses and Dissertations
The objective of this thesis is to quantify the improvement that can be obtained in sensor agent localization accuracy as a function of the number of multipath components that can be resolved. We assume that a known number sensor agents are located at unknown coordinates within a rectangular grid having anchors at the corner locations, whose locations are known. Further, we assume fading is Rayleigh and that the propagation constant is constant but unknown. Also, we assume that modulation is spread spectrum and that either the sensors or agents are capable of resolving multipath components down to the chip level …
Critical Analysis Of Transmitarray Antenna Design, Ahmed H. Abdelrahman
Critical Analysis Of Transmitarray Antenna Design, Ahmed H. Abdelrahman
Electronic Theses and Dissertations
In recent years, transmitarray antenna concept attracts growing interests of many scientists in the antenna area. It combines the favorable features of the lens antenna that are based on optical theory and the microstrip arrays that are based on array theory, leading to a low profile design with high gain, high radiation efficiency, and flexible radiation performance. Transmitarrays are now emerging as a new generation of high-gain antennas for long-distance communications. In this dissertation, comprehensive analysis, new methodologies, and novel designs of transmitarray antennas are presented. * detailed analysis of the design of planar space fed array antennas is presented. …
Design And Analysis Of Reconfigurable Sensing Antennas For Wireless Sensing Applications, Qian Qiao
Design And Analysis Of Reconfigurable Sensing Antennas For Wireless Sensing Applications, Qian Qiao
Electronic Theses and Dissertations
Reconfiguration sensing antenna (rsa) is a novel antenna concept, which not only can transmit or receive radio waves but also can sense the surrounding environment. The environment sensing is realized by reconfiguring the antenna's characteristics, such as resonant frequency, and radar cross section (rcs). The rsas possess the advantages of passive and low cost, which make them suitable for the large-scale wireless sensing networks (wsns) deployment. In this dissertation, the rsas concept is demonstrated, and two sensing mechanisms performed in the rsas are investigated. In order to verify these sensing mechanisms, four rsas are designed, analyzed, and measured. All the …
Adaptive Encryption Techniques In Wireless Communication Channels With Tradeoffs Between Communication Reliability And Security, Walid Al Zibideh
Adaptive Encryption Techniques In Wireless Communication Channels With Tradeoffs Between Communication Reliability And Security, Walid Al Zibideh
Electronic Theses and Dissertations
Encryption is a vital process to ensure the confidentiality of the information transmitted over an insecure wireless channel. However, the nature of the wireless channel tends to deteriorate because of noise, interference and fading. Therefore, a symmetrically encrypted transmitted signal will be received with some amount of error. Consequently, due to the strict avalanche criterion (sac), this error propagates during the decryption process, resulting in half the bits (on average) after decryption to be in error. In order to alleviate this amount of error, smart coding techniques and/or new encryption algorithms that take into account the nature of wireless channels …
Enhancing Wireless Security Using Relay Based Cooperative Networks., Mohammad A. Kishk
Enhancing Wireless Security Using Relay Based Cooperative Networks., Mohammad A. Kishk
Electronic Theses and Dissertations
No abstract provided.
Characteristics Of Different Focusing Antennas In The Near Field Region, Shaya Karimkashi
Characteristics Of Different Focusing Antennas In The Near Field Region, Shaya Karimkashi
Electronic Theses and Dissertations
Focusing antennas are of interest in many application including microwave wireless power transmission, remote (non-contact) sensing, and medical applications. Different kinds of antennas such as array antennas, reflector antennas and Fresnel zone plate (FZP) antennas have been used for these applications. Here, first, a new scheme in designing focused array antennas with desired sidelobe levels (SLLs) in the near field region is presented. The performance of the large focused array antennas is predicted based on the knowledge of the mutual admittances of a smaller array. The effects of various focal distances on the near field pattern of these antennas are …
Analysis Of Periodic Structures Using Finite-Difference Time-Domain Method, Khaled Elmahgoub
Analysis Of Periodic Structures Using Finite-Difference Time-Domain Method, Khaled Elmahgoub
Electronic Theses and Dissertations
Periodic structures are of great importance in electromagnetics these days due to their wide range of applications such as frequency selective surfaces (FSS), electromagnetic band gap, periodic absorbers, metamaterials and many others. The aim of this work is to develop several algorithms to analyze different types of electromagnetic periodic structures using the constant horizontal wavenumber finite-difference time-domain periodic boundary condition (FDTD/PBC). A new FDTD/PBC approach is introduced to analyze the scattering properties of general skegrid periodic structures. The approach is simple to implement and efficient in terms of both computational time and memory usage. In addition, an efficient hybrid FDTD …
Using Bayesian Inference In Design Applications, Chung Yong Chan
Using Bayesian Inference In Design Applications, Chung Yong Chan
Electronic Theses and Dissertations
This dissertation presents a new approach for solving engineering design problems such as the design of antenna arrays and finite impulse response (FIR) filters. In this approach, a design problem is cast as an inverse problem. The tools and methods previously developed for Bayesian inference are adapted and utilized to solve design problems. Given a desired design output, Bayesian parameter estimation and model comparison are employed to produce designs that meet the prescribed design specifications and requirements. In the Bayesian inference framework, the solution to a design problem is the posterior distribution, which is proportional to the product of the …