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Articles 1 - 12 of 12
Full-Text Articles in Engineering
Prepulse Inhibition Of The Acoustic Startle Reflex: Comparing Low And High Trait Anxious Individuals, Krista Sturm
Prepulse Inhibition Of The Acoustic Startle Reflex: Comparing Low And High Trait Anxious Individuals, Krista Sturm
Honors Theses
This investigation examined whether prepulse inhibition of the acoustic startle reflex was impaired among individuals with high trait anxiety compared to controls. PPI has traditionally been theorized to be a psychophysiological index of information processing and sensorimotor gating, and is now being used to help identify various psychological disorders. Although results of existing research on reduced PPI across the anxiety spectrum are equivocal, previous findings indicate that highly anxious (HA) participants exhibit significantly reduced PPI at lead intervals of 60 ms relative to low anxious (LA) controls. This study paired a 70 dB (A) white noise prepulse stimulus with a …
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 …
Analysis And Design Of Low Profile Multiband Multifunctional Antenna Arrays, Walker F. Hunsicker
Analysis And Design Of Low Profile Multiband Multifunctional Antenna Arrays, Walker F. Hunsicker
Electronic Theses and Dissertations
Light-weight phased array antennas for aerospace and mobile applications require utilizing the same antenna aperture to provide multiple functions with dissimilar radiation pattern specifications (e.g., multiband operation for communications and tracking). Multi-functional antennas provide advantages over aggregate antenna clusters by reducing space requirements, and can aid in the optimal placement of all required apertures to provide adequate isolation between channels. Furthermore, the combination of antenna apertures into a comgeometry mitigates co-site installation issues by addressing interference within the integrated radiator design itself as opposed to the extensive analysis which is required to configure multiple radiators in close proximity. The combination …
A Complex-Envelope Fdtd Formulation Using Real-Valued Field-Variables, Qi Liu
A Complex-Envelope Fdtd Formulation Using Real-Valued Field-Variables, Qi Liu
Electronic Theses and Dissertations
Use of the complex-envelope (CE) representation of band-pass limited sources and their resulting fields increases the allowable time-step in finite-difference time-domain (FDTD) simulations. The complex envelope representation transforms band-pass limited fields and sources to complex-valued low-pass limited form and Maxwells equations from real-valued partial differential equations (PDEs) to complex-valued PDEs. Previous CE FDTD schemes have used complex valued difference equations in terms of complex valued field quantities to approximate these complex PDEs. This choice requires the use of complex numbers and complex operations in the computer program implementing the solution. An alternative CE FDTD scheme using only real numbers and …
Reconfigurable Microstrip Antennas With Tunable Radiation Pattern Characteristics, Ahmed Khidre
Reconfigurable Microstrip Antennas With Tunable Radiation Pattern Characteristics, Ahmed Khidre
Electronic Theses and Dissertations
Reconfigurable beam antenna systems are capable of changing their radiation characteristics in real time, such as beam direction, beam shape, beamwidth, etc. Such antenna system is desired for various wireless applications because of many reasons among them; it helps to enhance signal strength received from an intended target, mitigates interference, and accommodates sudden changes in traffic demand of wireless networks. It might also help to reduce the deployment cost of wireless networks infrastructures. In this dissertation, designs for reconfigurable beam microstrip antennas with tunable radiation characteristics have been proposed. The method to achieve these designs is the reconfigurable parasitic element …
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 …
Broadband Approaches And Beam-Scanning Techniques For Reflectarray Antenna, Yilin Mao
Broadband Approaches And Beam-Scanning Techniques For Reflectarray Antenna, Yilin Mao
Electronic Theses and Dissertations
Reflectarray antennas combine the numerous advantages of reflector antennas and phased array antennas and create a hybrid high-gain antenna with a low-profile, low-mass, easy-fabrication, and diversified radiation performance. However, it still has some inherent drawbacks, such as limited bandwidth and scanning range, which are targeted in this dissertation. At first, the array theory approach for radiation analysis of reflectarray antennas is described and implemented. Numerical results are then presented and compared with reference results to confirm its reliability. As the most critical influential factor to the reflectarray bandwidth, the element bandwidth was studied at first, and the effects of element …
Processor, Payload, And Power Subsystem Development Of The Missat-1 Cubesat, Rana Roxanne Gordji, Zachary Christian Puuwai Olaa Morgan, Samuel Liyang Di
Processor, Payload, And Power Subsystem Development Of The Missat-1 Cubesat, Rana Roxanne Gordji, Zachary Christian Puuwai Olaa Morgan, Samuel Liyang Di
Honors Theses
This thesis details the development and programming of the processor subsystem, camera payload, and power subsystem of the Mississippi Imaging Space Satellite (MISSat-1). An overview of the hardware and software considerations necessary for the processor subsystem is discussed. An explanation of microcontroller uses as well as real time operating system fundamentals is also presented as it relates to MISSat-1. The subsystem deals with varieties of peripheral integration and communication standards among devices. The camera graphical user interface (GUI) was expanded with the addition of functions that improve CubeSat image handling. Additionally, image processing techniques and algorithms are considered to improve …