Electrical and Electronics Commons^™

Analysis Of Vehicle Interactions On Interstate Highways: Discrete Choice And Linear System Approaches, Alicia Romo

Open Access Theses & Dissertations

The research in this dissertation developed statistical and linear system models to predict driving behavior according to driver attributes, vehicle characteristics, car-following dynamics and/or driving conditions. The scope of this research was limited to the interaction of two vehicles traveling in the same direction on interstate highways.

The statistical models proposed in this research investigated the contributions of the different vehicle types on the manner and likelihood of collision. Discrete choice models were used to estimate the probability of the types of collision (rear-end, angle and sideswipe) as functions of driver attributes, striking and struck vehicle types, pre-crash driving actions …

Ultrawideband (Uwb) And Reconfigurable Antennas - New Concepts For Conformal Load Bearing Antenna Structures (Clas), Nicholas Bishop

Theses and Dissertations

Conformal antennas have been increasingly playing an important role in a vast number wireless of communication applications. More specifically, Conformal Load Bearing Antenna Structures (CLAS) have drawn a great deal of interest among researchers and engineers because of their advantages of multiple functionality, e.g. antenna and structure both. The objectives of this thesis are to investigate and design innovative conformal Ultrawideband (UWB) endfire antenna arrays and reconfigurable aperture coupled pixel patch antennas both of which are good candidates for CLAS. First, a broadband VHF-UHF end-fire Yagi-Uda array is proposed for possible air vehicle integration and operation within the 240-465 MHz …

Analysis Of Modulation And Voltage Balancing Strategies For Modular Multilevel Converters, Ryan Blackmon

Theses and Dissertations

Modular multilevel converters are an emerging voltage source converter topology suitable for many applications. The increased utilization of HVDC power transmission solutions has resulted in modular multilevel converters becoming a more common converter type. Other applications include interfacing renewable energy power sources to the grid and motor drives. Modular multilevel converters are beneficial for medium voltage motor drives because the properties of this converter topology, such as low distortion, allow for an efficient motor drive design.

Modular multilevel converters are designed where instead of using 6 IGBTs as in a conventional voltage source converter, numerous low-rated IGBTs are used to …

Effects Of N-Type Doping On Algan Material Quality, Devendra Diwan

Theses and Dissertations

The field of group III-nitride semiconductors has seen incredible developments during last couple of decades. They are recognized as the most promising materials for a wide field of optoelectronics and electronic devices. Their bandgap ranges from 6.2 eV for AlN to 0.7 eV for InN, covering a wide spectral range from infrared (1.77 mm) to deep ultraviolet (200 nm). Their direct bandgap makes them useful for fabricating optoelectronic devices such as light emitting diodes (LEDs), laser diodes (LDs), and photodetectors. III-nitride semiconductor materials also possess strong bond strengths and exhibit good structural, chemical and thermal stability. These properties make it …

Polyspectral Signal Analysis Techniques For Condition Based Maintenance Of Helicopter Drive-Train System, Mohammed Ahmed Hassan Mohammed

Theses and Dissertations

For an efficient maintenance of a diverse fleet of air- and rotorcraft, effective condition based maintenance (CBM) must be established based on rotating components monitored vibration signals.

In this dissertation, we present theory and applications of polyspectral signal processing techniques for condition monitoring of critical components in the AH-64D helicopter tail rotor drive train system. Currently available vibration-monitoring tools are mostly built around auto- and cross-power spectral analysis which have limited performance in detecting frequency correlations higher than second order. Studying higher order correlations and their Fourier transforms, higher order spectra, provides more information about the vibration signals which helps …

High Performance Rf Control Devices Using Capacitively Coupled Contacts (C3) Over Iii-N Heterostructures, Faisal Jahan

Theses and Dissertations

RF switches, power limiters and other control devices are essential components of modern RF systems. RF switches are important parts of wireless modules of various devices such as laptops, tablets, cell phones etc. and key components of satellites communication systems, radars, multi-band wireless and aerospace communications, phased array antennas. RF Power limiters (PL) are also important components of RF systems protecting linear amplifiers, detectors etc. from high-power stress. Traditionally, RF switches are fabricated using pin diodes or MEMS, Si MOSFETs or GaAs HEMTs. RF PLs are typically implemented using Schottky or pin-diodes. Traditional devices used in RF switch and PLs …

Impedance Estimation Using Randomized Pulse Width Modulation And Power Converters, William M. Mccoy

Theses and Dissertations

With the adoption of technologies such as alternative energy production, DC power grids, and electric vehicles, the use of high power switching converters has seen a dramatic increase. These power converters serve many rolls such as grid-tied inverters in solar farms, high power charging for electric vehicles, motor drives for industrial applications, and DC links in transmission systems. With the increased prevalence of such devices, it is only natural to attempt to optimize their operation. As with any level of converter, it is desirable to have accurate control over the generated voltages and currents. Often, these controllers implement some form …

High Resistivity Amorphous Selenium Alloy Semiconductors For Radiation Detection Applications, Abhinav Mehta

Theses and Dissertations

High resolution noninvasive tools of diagnosis has always derived and enabled scientific and medical research to probe and better understand subtleties of matter, intangible to the human eye. Radiation detection systems are highly dependent on advancements in materials and devices with front-end electronics. There are various discrete applications of these radiation detectors and each application imposes certain requirements so there is no single optimum radiation detector.

Flat panel x-ray imagers have gained high demand in the past decade because of exponential improvement in readout electronics. We have synthesized and investigated stabilized amorphous selenium (a-Se) alloys suitable for high resolution flat …

Wireless Pressure Sensor System For Medical Applications, Xuehe Wang

Theses and Dissertations

Telemedicine in the modern era is a rapidly developing industry. In a telemedicine system, sensor is the key elements and play important role in any telemedicine applications, especially implantable sensors. Unlike traditional in vitro sensors, there are some special requirements for them like battery-less, compact, and bio-friendly. Therefore, many researchers in institutes as well as in industry are continually developing implantable sensor and sensor system to fulfill the requirements of medical applications.Nine in one thousand people in the United States are born with congenital heart defects and sixty percent die before one year old. As a result, it will be …

Antenna Designs For Wireless Medical Implants., Conor P. Conran

Masters

Active medical implants are devices that are surgically implanted inside the body. They have been developed to treat a wide range of ailments and many require some form of communications link with the outside world for maintenance and for remote medical diagnostics. Radio links promise a wide range of benefits over the traditional low frequency inductive coupling method.

Body tissue is a challenging environment, both for the device and for the radio signal that it transmits. Innovation in medical technology is creating a demand for high bandwidth links, and this in turn is driving the development of implantable antennas.

Many …

The Influence Of Light Beam Convergence On The Stop-Bands Of A One-Dimensional Photonic Crystal, Vladimir A. Tolmachev, Kevin Berwick, Tatiana S. Perova

Articles

The influence of beam convergence on the photonic band-gaps, or stop-bands (SBs), of onedimensional photonic crystals (1D PCs) is investigated. The investigation is based on an analysis of the gap map obtained from reflection spectra, calculated by the transfer matrix method for various angles of light incidence, φ, The calculated data is compared with reflection spectra taken using Fourier Transform Infrared microspectroscopy. It was found that the introduction of the parameter, Δφ to account for the focused light beam, for angles up to 20°, has little effect on the first, or lowest SB and the SBs adjacent to it. However, …

Reversible Photoluminescence Quenchin Of Cdse/Zns Quantum Dots Embedded In Porous Glass By Ammonia Vapor, A. O. Orlova, Yu A. Gromova, V. G. Maslov, O. V. Andreeva, A. V. Baranov, A. V. Federov, A. V. Prudnikau, M. V. Artemyev, Kevin Berwick

Articles

The photoluminescence response of semiconductor CdSe/ZnS quantum dots embedded in a borosilicate porous glass matrix to exposure to ammonia vapor is investigated. Formation of surface complexes on the quantum dots results in quenching of the photoluminescence and a shortening of the luminescence decay time. The process is reversible, desorption of ammonia molecules from the quantum dot surface causes the photoluminescence to recover. The sensitivity of the quantum dot luminescence intensity and decay time to the interaction time and the reversibility of the photoluminescence changes makes the CdSe/ZnS quantum dot in porous glass system a candidate for use as an optical …

Community Microgrid Based On Micro-Wind Generation System, Lubna Mariam, Malabika Basu, Michael Conlon

Conference papers

Penetration of renewable energy sources (such as solar/wind) are being explored mostly as micro power generation (μGen) or mega power plant system. In recent years, emphasis has been given on Microgrid (μGrid) systems because of their few advantages over μGen systems in terms of power quality, stability, reliability, economics etc. But the commercial installation of the μGrid system is not yet progressing significantly. This paper presents the techno-economic aspects of μGen and μGrid systems towards the development of grid connected community based μGrid (C-μGrid) system. Emphasis has been given to identify the benefits of the μGrid over the μGen system. …

A New Placement And Integration Method Of Upqc To Improve The Power Quality In Dg Network, Shafiuzzaman K. Khadem, Malabika Basu, Michael Conlon

Conference papers

A new proposal for the placement and integration of UPQC in DG connected microgrid/micro generation (μG) system has been presented here. DG converters (with storage), the load and shunt part of the UPQC will be placed at or after the PCC. The series part of the UPQC will be placed before the PCC and in series with the grid. DC link can be connected to the storage system also. Hence, it is termed UPQCμ_G. The advantages of the proposed UPQCμ_G over the normal UPQC are to compensate voltage interruptions in addition to voltage sags / swells, harmonic …

Economic Challenges And Optimisation Of Ocean Energy Electrical Systems, Fergus Sharkey

Books/Book chapters

No abstract provided.

Effect Of Hafnium-Incorporation On The Microstructure And Dielectric Properties Of Cobalt Ferrite Ceramics, Stephen Josiah Wells

Open Access Theses & Dissertations

The effect of hafnium ion (Hf⁴⁺) incorporation in cobalt ferrite (CFO) was studied. Samples of Hf substituted CFO ceramic (CoFe_2-xHf_xO₄), were synthesized in the laboratory with hafnium concentrations ranging from x=0.000 to x=0.200. X-ray diffraction scans show that the Hafnium CFO crystalizes in the inverse spinel phase. Inclusion of hafnium causes lattice expansion, increasing the lattice parameter from 8.374 í? for pure CoFe2O4 to 8.391 í? for the highest concentration of hafnium tested (x=0.020). The dielectric properties of CFO are greatly enhanced by inclusion of hafnium. The enhancement is due to the …

Reduced-Order Modeling Using Orthogonal And Bi-Orthogonal Wavelet Transforms, Miguel Hernandez Iv

Open Access Theses & Dissertations

It is well known that model reduction methods borrow techniques typically found in data compression, and current state-of-the-art techniques for data compression are based on the wavelet transform. Given these facts, it is surprising that model reduction using wavelets has not received much attention and has not been adequately addressed in the literature. This research seeks to determine if wavelets can be used for model reduction and if wavelet model reduction is a viable alternative to existing model reduction methods.

In this work we propose a novel method for model reduction using wavelets. Specifically, we introduce techniques for deriving wavelet …