Electrical and Computer Engineering Commons^™

The Development Of Scalable Pump Techniques For Gg Iag Fiber Lasers And Passive Athermalization Techniques For Solid State Laser, William Hageman

Electronic Theses and Dissertations

This dissertation consists of two parts: research pertaining to the development of scalable pump techniques for gain guided index-antiguided fiber lasers and research relating to the development of passive athermalization schemes for solid state lasers. The first section primarily details the development of a side pump scheme that allows for power scaling of gain-guided index anti-guided fibers. While these fibers have been demonstrated in past research, none have used a pump technology capable of pumping with the efficiencies, uniformity, and necessary length to allow for scaling of the fiber lasers to high output powers. The side pumped scheme developed in …

Mitigating Misbehavior In Wireless Networks: A Game Theoretic Approach, Wenjing Wang

Electronic Theses and Dissertations

In a distributed wireless system, multiple network nodes behave cooperatively towards a common goal. Though such assumptions on cooperation are desirable (e.g., controlling the transmit power level, reducing interference for each other, revealing private information, adhering to network policies) for analyzing and modeling, certain nodes belonging to a real-world system have often shown to deviate. These nodes, known as misbehaving nodes, bring more challenges to the design of the wireless network because the unreliable channel makes the actions of the nodes hidden from each other. In this dissertation, we analyze two types of misbehavior, namely, selfish noncooperation and malicious attacking. …

Near-Field Optical Interactions And Applications, David Haefner

Electronic Theses and Dissertations

The propagation symmetry of electromagnetic fields is affected by encounters with material systems. The effects of such interactions, for example, modifications of intensity, phase, polarization, angular spectrum, frequency, etc. can be used to obtain information about the material system. However, the propagation of electromagnetic waves imposes a fundamental limit to the length scales over which the material properties can be observed. In the realm of near-field optics, this limitation is overcome only through a secondary interaction that couples the high-spatial-frequency (but non-propagating) field components to propagating waves that can be detected. The available information depends intrinsically on this secondary interaction, …

Laser Plasma Radiation Studies For Droplet Sources In The Extreme Ultraviolet, Reuvani Kamtaprasad

Electronic Theses and Dissertations

The advancement of laboratory based Extreme Ultraviolet (EUV) radiation has escalated with the desire to use EUV as a source for semiconductor device printing. Laser plasmas based on a mass-limited target concept, developed within the Laser Plasma Laboratory demonstrate a much needed versatility for satisfying rigorous source requirements. This concept produces minimal debris concerns and allows for the attainment of high repetition rates as well as the accommodation of various laser and target configurations. This work demonstrates the generation of EUV radiation by creating laser plasmas from mass-limited targets with indium, tin, and antimony doped droplets. Spectral emission from the …

Characterization And Modeling Of A High Power Thin Disk Laster, Omar Rodriguez-Valls

Electronic Theses and Dissertations

High power lasers have been adapted to material processing, energy, military and medical applications. In the Laser Plasma Laboratory at CREOL, UCF, high power lasers are used to produce highly ionized plasmas to generate EUV emission. This thesis examines the quality of a recently acquired high power thin disk laser through thermal modeling and beam parameter measurements. High power lasers suffer from thermally induced issues which degrade their operation. Thin disk lasers use an innovative heat extraction mechanism that eliminates the transverse thermal gradient within the gain medium associated with thermal lensing. A thorough review of current thin disk laser …

A New Development Of Feedback Controller For Left Ventricular Assist Device, Yu Wang

Electronic Theses and Dissertations

The rotary Left Ventricular Assist Device (LVAD) is a mechanical pump surgically implanted in patients with end-stage congestive heart failure to help maintain the flow of blood from the sick heart. The rotary type pumps are controlled by varying the impeller speed to control the amount of blood flowing through the LVAD. One important challenge in using these devices is to prevent the occurrence of excessive pumping of blood from the left ventricle (known as suction) that may cause it to collapse due to the high pump speed. The development of a proper feedback controller for the pump speed is …

Micro-Electro-Mechanical Systems (Mems) And Agile Lensing-Based Modules For Communications, Sensing And Signal Processing., Syed Reza

Electronic Theses and Dissertations

This dissertation proposes the use of the emerging Micro-Electro-Mechanical Systems (MEMS) and agile lensing optical device technologies to design novel and powerful signal conditioning and sensing modules for advanced applications in optical communications, physical parameter sensing and RF/optical signal processing. For example, these new module designs have experimentally demonstrated exceptional features such as stable loss broadband operations and high > 60 dB optical dynamic range signal filtering capabilities. The first part of the dissertation describes the design and demonstration of digital MEMS-based signal processing modules for communication systems and sensor networks using the TI DLP (Digital Light Processing) technology. Examples of …

Development Of An Improved Microwave Ocean Surface Emissivity Radiative Transfer Model, Salem El-Nimri

Electronic Theses and Dissertations

An electromagnetic model is developed for predicting the microwave blackbody emission from the ocean surface over a wide range of frequencies, incidence angles, and wind vector (speed and direction) for both horizontal and vertical polarizations. This ocean surface emissivity model is intended to be incorporated into an oceanic radiative transfer model to be used for microwave radiometric applications including geophysical retrievals over oceans. The model development is based on a collection of published ocean emissivity measurements obtained from satellites, aircraft, field experiments, and laboratory measurements. This dissertation presents the details of methods used in the ocean surface emissivity model development …

Experimental Investigation Of Magnetic Circular Dichroism Spectrum And Stress Induced Optical Activity In A Single-Defect Photonic Crystal, Mikhail Vasiliev, Kamal Alameh, Vladimir I. Burkov, V. V. Koledov, Viacheslav A. Kotov, V. G. Shavrov, Anotoly K. Zvezdin

Research outputs pre 2011

Experimental investigation results for the magnetic circular dichroism spectrum (MCD) of a photonic crystal (PC) are presented. We found that in the vicinity of the transmission peak within the photonic bandgap and also near the bandgap edges, the circular dichroism is measurable even in the absence of any applied magnetic field. The application of magnetic field leads to generating an additional MCD signal measurable at the wavelengths near the “defect mode” transmittance line.

Intelligent Irrigation Zone Splitter, David Boeck

Electrical Engineering

The intelligent irrigation zone splitter allows easy expansion of an existing irrigation controller. To expand on an existing controller a new wire is needed to run between the controller and the valve. This path may be buried beneath driveways, patios, and sidewalks. The intelligent irrigation zone splitter uses an already existing wire path to control two valves and create a new watering zone. This controller uses timing and memory to split the total watering time of the zone.

Dual Axis Solar Tracker, Weston Sapia, Jason Birnie

Electrical Engineering

No abstract provided.

Dynamic Reconfiguration And Control Of Smart Power Systems, Pinaki Mitra

Doctoral Dissertations

"To address the increasing demand and complexity, modern power systems need intelligence at almost all levels which can transform them into 'smart' power systems. The term 'smart power systems' not only refers to the terrestrial power systems with a significant penetration of distributed energy resources and energy storage such as plug-in electric vehicle parking lots (SmartParks), but also includes other isolated power systems, such as the power systems of naval electric ships. The research presented in this dissertation contributes to the dynamic reconfiguration and control of both terrestrial and ship power system with the application of computational intelligence methods.

In …

Denoising Of Natural Images Using The Wavelet Transform, Manish Kumar Singh

Master's Theses

A new denoising algorithm based on the Haar wavelet transform is proposed. The methodology is based on an algorithm initially developed for image compression using the Tetrolet transform. The Tetrolet transform is an adaptive Haar wavelet transform whose support is tetrominoes, that is, shapes made by connecting four equal sized squares. The proposed algorithm improves denoising performance measured in peak signal-to-noise ratio (PSNR) by 1-2.5 dB over the Haar wavelet transform for images corrupted by additive white Gaussian noise (AWGN) assuming universal hard thresholding. The algorithm is local and works independently on each 4x4 block of the image. It performs …

Detection And Estimation Of Image Blur, Harish Narayanan Ramakrishnan

Masters Theses

"The airborne imagery consisting of infrared (IR) and multispectral (MSI) images collected in 2009 under airborne mine and minefield detection program by Night Vision and Electronic Sensors Directorate (NVESD) was found to be severely blurred due to relative motion between the camera and the object and some of them with defocus blurs due to various reasons. Automated detection of blur due to motion and defocus blurs and the estimation of blur like point spread function for severely degraded images is an important task for processing and detection in such airborne imagery. Although several full reference and reduced reference methods are …

Standoff Raman Spectroscopy Detection Of Trace Explosives, Abhijeet Singh

Masters Theses

"During the 2003-present Iraq war, Improvised Explosive Devices (IEDs) are being used extensively by the terrorists against the coalition forces and these IEDs were responsible for 40% of coalition force casualties, by the end of 2007. As these IEDs are not based on standard production formulae, their tracking and detection becomes extremely complicated. Laser Induced Breakdown Spectroscopy (LIBS) and Raman Spectroscopy are among the many techniques that have shown promise in detection of explosive compounds. However, the performance of these systems is dependent on the concentration of explosives and ambient noise.

The research presented in this thesis applies signal processing …

Characterization Of Atmospheric Turbulence Effects Over 149 Km Propagation Path Using Multi-Wavelength Laser Beacons, Mikhail Vorontsov, Gary W. Carhart, Venkata S. Rao Gudimetla, Thomas Weyrauch, Eric Stevenson, Svetlana Lachinova, Leonid A. Beresnev, Jony Jiang Liu, Karl Rehder, Jim F. Riker

Electrical and Computer Engineering Faculty Publications

We describe preliminary results of a set of laser beam propagation experiments performed over a long (149 km) near-horizontal propagation path between Mauna Loa (Hawaii Island) and Haleakala (Island of Maui) mountains in February 2010. The distinctive feature of the experimental campaign referred to here as the Coherent Multi-Beam Atmospheric Transceiver (COMBAT) experiments is that the measurements of the atmospheric-turbulence induced laser beam intensity scintillations at the receiver telescope aperture were obtained simultaneously using three laser sources (laser beacons) with different wavelengths (λ1 = 0.53 μm, λ2 = 1.06 μm, and λ3 = 1.55 μm). The presented experimental results on …

Modeling Biological Structures Via Abstract Grammars To Solve Common Problems In Computational Biology, David J. Russell

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Grammars are generally understood to be the set of rules that define the relationships between elements of a language. However, grammars can also be used to elucidate structural relationships within sequences constructed from any finite alphabet. In this work abstract grammars are used to model the primary and secondary structures present in biological data. These grammar models are inferred and applied to efficiently solve various sequence analysis problems in computational biology, including multiple sequence alignment, fragment assembly, database redundancy removal, and structural prediction.

The primary structures, or sequential ordering of symbols, of biological data are first modeled with Lempel-Ziv (LZ) …

Experimental Investigation Of Dielectric Barrier Impact On Breakdown Voltage Enhancement Of Copper Wire-Plane Electrode Systems, Elham Foruzan, M. Ziaee-Nezhad, A. A. Shayegani-Akmal, K. Niayesh

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Non-pressurized air is extensively used as basic insulation media in medium / high voltage equipments. An inherent property of air-insulated designs is that the systems tend to become physically large. Application of Dielectric barrier can increase the breakdown voltage and therefore decrease the size of the equipments.

In this paper, the impact of dielectric barrier on breakdown voltage enhancement of a copper wire-plane system is investigated. For this purpose, the copper wire is covered with different dielectric materials. Depending on the air gap and dielectric strength of the barrier the breakdown can be initiated in the solid or gas dielectric. …

Growth And Characterization Of Silicon Carbide Thin Films Using A Nontraditional Hollow Cathode Sputtering Technique, James Huguenin-Love

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Silicon carbide (SiC) is considered a suitable candidate for high-power, high-frequency devices due to its wide bandgap, high breakdown field, and high electron mobility. It also has the unique ability to synthesize graphene on its surface by subliming Si during an annealing stage. The deposition of SiC is most often carried out using chemical vapor deposition (CVD) techniques, but little research has been explored with respect to the sputtering of SiC.

Investigations of the thin film depositions of SiC from pulse sputtering a hollow cathode SiC target are presented. Although there are many different polytypes of SiC, techniques are discussed …

The Weakening Of Branch Predictor Performance As An Inevitable Side Effect Of Exploiting Control Independence, Christopher Joseph Michael

LSU Doctoral Dissertations

Many algorithms are inherently sequential and hard to explicitly parallelize. Cores designed to aggressively handle these problems exhibit deeper pipelines and wider fetch widths to exploit instruction-level parallelism via out-of-order execution. As these parameters increase, so does the amount of instructions fetched along an incorrect path when a branch is mispredicted. Many of the instructions squashed after a branch are control independent, meaning they will be fetched regardless of whether the candidate branch is taken or not. There has been much research in retaining these control independent instructions on misprediction of the candidate branch. This research shows that there is …