Physical Sciences and Mathematics Commons^™

Nonlinear Femtosecond Near Infrared Laser Structuring In Oxide Glasses, Arnaud Royon

Electronic Theses and Dissertations

Three-dimensional femtosecond laser structuring has a growing interest because of its ease of implementation and the numerous possible applications in the domain of photonic components. Structures such as waveguides, diffraction gratings, optical memories or photonic crystals can be fabricated thanks to this technique. Its use with oxide glasses is promising because of several advantages; they are resistant to flux and ageing, their chemical composition can easily be changed to fit the well-defined requirements of an application. They can already be found in Raman amplifiers, optical fibers, fiber lasers, and other devices. This thesis is based on two axes. The first …

Realnav: Exploring Natural User Interfaces For Locomotion In Video Games, Brian Williamson

Electronic Theses and Dissertations

We present an exploration into realistic locomotion interfaces in video games using spatially convenient input hardware. In particular, we use Nintendo Wii Remotes to create natural mappings between user actions and their representation in a video game. Targeting American Football video games, we used the role of the quarterback as an exemplar since the game player needs to maneuver effectively in a small area, run down the field, and perform evasive gestures such as spinning, jumping, or the "juke". In our study, we developed three locomotion techniques. The first technique used a single Wii Remote, placed anywhere on the user's …

Room Temperature Fluorescence Spectroscopy As A Tool For The Forensic Trace Analysis Of Textile Fibers, Matthew Rex

Electronic Theses and Dissertations

Trace textile fiber evidence is found at numerous crime scenes and plays an important role in linking a suspect to the respective scene. Several methods currently exist for the analysis of trace fiber evidence. Microscopy provides information regarding the fibers material, color and weave. For more detailed chemical analysis chromatographic methods are employed and for discrimination between dyes, liquid chromatography coupled with mass spectrometry (LC-MS) is currently the method providing the most discrimination. These methods have primarily focused on the dyes used to color the fibers and have not investigated other components that can potentially discriminate among fibers. This dissertation …

Electron Transport In Single Molecule Magnet Transistors And Optical Lambda Transitions In The Nitrogen-Vacancy Center In Diamon, Gabriel Gonzalez

Electronic Theses and Dissertations

This thesis presents some theoretical studies dealing with quantum interference effects in electron transport through single molecule magnet transistors and a study on optical non-conserving spin transitions in the Nitrogen-vacancy center in diamond. The thesis starts with a brief general introduction to the physics of quantum transport through single electron transistors. Afterwards, the main body of the thesis is divided into three studies: (i) In chapter (2) we describe the properties of single molecule magnets and the Berry phase interference present in this nanomagnets. We then propose a way to detect quantum interference experimentally in the current of a single …

Vectorpad: A Tool For Visualizing Vector Operations, Jared Bott

Electronic Theses and Dissertations

Visualization of three-dimensional vector operations can be very helpful in understanding vector mathematics. However, creating these visualizations using traditional WIMP interfaces can be a troublesome exercise. In this thesis, we present VectorPad, a pen-based application for three-dimensional vector mathematics visualization. VectorPad allows users to define vectors and perform mathematical operations upon them through the recognition of handwritten mathematics. The VectorPad user interface consists of a sketching area, where the user can write vector definitions and other mathematics, and a 3D graph for visualization. After recognition, vectors are visualized dynamically on the graph, which can be manipulated by the user. A …

Femtosecond Laser Written Volumetric Diffractive Optical Elements And Their Applications, Jiyeon Choi

Electronic Theses and Dissertations

Since the first demonstration of femtosecond laser written waveguides in 1996, femtosecond laser direct writing (FLDW) has been providing a versatile means to fabricate embedded 3-D microstructures in transparent materials. The key mechanisms are nonlinear absorption processes that occur when a laser beam is tightly focused into a material and the intensity of the focused beam reaches the range creating enough free electrons to induce structural modification. One of the most useful features that can be exploited in fabricating photonic structures is the refractive index change which results from the localized energy deposition. The laser processing system for FLDW can …

Concept Learning By Example Decomposition, Sameer Joshi

Electronic Theses and Dissertations

For efficient understanding and prediction in natural systems, even in artificially closed ones, we usually need to consider a number of factors that may combine in simple or complex ways. Additionally, many modern scientific disciplines face increasingly large datasets from which to extract knowledge (for example, genomics). Thus to learn all but the most trivial regularities in the natural world, we rely on different ways of simplifying the learning problem. One simplifying technique that is highly pervasive in nature is to break down a large learning problem into smaller ones; to learn the smaller, more manageable problems; and then to …

Characterization Of Firn Microstructure Using Scanning Electron Microscopy: Implications For Physical Properties Measurements And Climate Reconstructions, Nicole Spaulding

Electronic Theses and Dissertations

Samples from 12 East Antarctic firn and ice cores were analyzed using scanning electron micrcoscopy (SEM) in order to first develop a technique for the accurate characterization of physical properties and then to investigate the relationship between the physical microstructure and chemical properties. Both physical properties, such as grain size and porosity, and chemical properties, such as major ion and trace element concentration, provide information about atmospheric temperature changes, impurity content, accumulation rate and deformation history; therefore the characterization of both types of properties is necessary. Further, knowledge of the relationship between the physical and chemical properties may increase our …

Geodynamics Of Terrane Accretion Within Southern Alaska, Benjamin Patrick Hooks

Electronic Theses and Dissertations

The subduction and accretion of an exotic terrane at the southern margin of Alaska is driving uplift of the St. Elias and Alaska Ranges, and is responsible for some of the largest strain releases in history. Here are presented results from numerical models conditioned by geological observations that reproduce the tectonic landscape, deformation, and strain patterns at macro- (1000-km) and meso- (<100 >km) scales. These models utilize completely coupled thermal and mechanical solutions that account for the development of heterogeneities to both the thermal and rheological structure of the lithosphere. Perturbation to the thermal structure related to flattening of the …

Modeling Ice Streams, Aitbala Sargent

Electronic Theses and Dissertations

Modeling glacier and ice sheet flow is a computationally challenging problem. The most challenging part in simulating ice sheet flow is modeling the fastest moving part of ice sheets, ice streams. In the first part of the thesis, we have constructed two numerical models of isothermal ice stream flow, a three-dimensional full-Stokes ice-sheet/ice-stream/ice-shelf model and a modified MacAyeal-Morland ice-stream/ice-shelf model. In the second part of the thesis, we studied the possibility of using SuperLU-DIST multiprocessor software package for solving the systems of linear equations generated by the model. The uniqueness of the modified MacAyeal-Morland model is in its inclusion of …

The Biochemical Reactions Of Dry State Dna, April Marrone

Electronic Theses and Dissertations

The biochemistry of dry state DNA is of interest to the fields of forensics, ancient DNA, and DNA storage. The exact chemical nature of the degradation of the DNA molecule in the dry state has not been studied prior. If determined what chemical changes the DNA molecule undergoes, to what degree and in what time frame then protocols can be implemented to bypass the impact of this damage or to repair it when necessary. It is suspected that similar reactions occur to the dry state DNA molecule as does to the hydrated molecule. It cannot be assumed, however that these …

Wavefront Sensor For Eye Aberrations Measurements, Costin Curatu

Electronic Theses and Dissertations

Ocular wavefront sensing is vital to improving our understanding of the human eye and to developing advanced vision correction methods, such as adaptive optics, customized contact lenses, and customized laser refractive surgery. It is also a necessary technique for high-resolution imaging of the retina. The most commonly used wavefront sensing method is based on the Shack-Hartmann wavefront sensor. Since Junzhong Liang's first application of Shack-Hartmann wavefront sensing for the human eye in 1994, the method has quickly gained acceptance and popularity in the ophthalmic industry. Several commercial Shack-Hartmann eye aberrometers are currently available. While the existing aberrometers offer reasonable measurement …

Learning Semantic Features For Visual Recognition, Jingen Liu

Electronic Theses and Dissertations

Visual recognition (e.g., object, scene and action recognition) is an active area of research in computer vision due to its increasing number of real-world applications such as video (image) indexing and search, intelligent surveillance, human-machine interaction, robot navigation, etc. Effective modeling of the objects, scenes and actions is critical for visual recognition. Recently, bag of visual words (BoVW) representation, in which the image patches or video cuboids are quantized into visual words (i.e., mid-level features) based on their appearance similarity using clustering, has been widely and successfully explored. The advantages of this representation are: no explicit detection of objects or …

Permutation Patterns, Reduced Decompositions With Few Repetitions And The Bruhat Order, Daniel Alan Daly

Electronic Theses and Dissertations

This thesis is concerned with problems involving permutations. The main focus is on connections between permutation patterns and reduced decompositions with few repetitions. Connections between permutation patterns and reduced decompositions were first studied various mathematicians including Stanley, Billey and Tenner. In particular, they studied pattern avoidance conditions on reduced decompositions with no repeated elements. This thesis classifies the pattern avoidance and containment conditions on reduced decompositions with one and two elements repeated. This classification is then used to obtain new enumeration results for pattern classes related to the reduced decompositions and introduces the technique of counting pattern classes via reduced …

Automatic Graphics And Game Content Generation Through Evolutionary Computation, Erin Hastings

Electronic Theses and Dissertations

Simulation and game content includes the levels, models, textures, items, and other objects encountered and possessed by players during the game. In most modern video games and simulation software, the set of content shipped with the product is static and unchanging, or at best, randomized within a narrow set of parameters. However, ideally, if game content could be constantly and automatically renewed, players would remain engaged longer in the evolving stream of content. This dissertation introduces three novel technologies that together realize this ambition. (1) The first, NEAT Particles, is an evolutionary method to enable users to quickly and easily …

Dense Spectral Beam Combining With Volume Bragg Gratings In Photo-Thermo-Refractive Glass, Oleksiy Andrusyak

Electronic Theses and Dissertations

Beam combining techniques have become an important tool in the design of high-power high-brightness laser systems. Spectral beam combining (SBC) is an incoherent combining technique that does not require phase control of sources, allowing for a stable and robust system. Using SBC, beams from an array of lasers with each element operated at a different wavelength are combined into a single near-diffraction-limited beam with the same aperture using dispersive optical elements. SBC by means of volume Bragg gratings (VBGs) utilizes unique spectral response of VBGs: diffraction efficiency is close to unity when the Bragg condition is satisfied and is close …

Design, Analysis, And Optimization Of Diffractive Optical Elements Under High Numerical Aperture Focusing, Toufic Jabbour

Electronic Theses and Dissertations

The demand for high optical resolution has brought researchers to explore the use of beam shaping diffractive optical elements (DOEs) for improving performance of high numerical aperture (NA) optical systems. DOEs can be designed to modulate the amplitude, phase and/or polarization of a laser beam such that it focuses into a targeted irradiance distribution, or point spread function (PSF). The focused PSF can be reshaped in both the transverse focal plane and along the optical axis. Optical lithography, microscopy and direct laser writing are but a few of the many applications in which a properly designed DOE can significantly improve …

Heuristics For Improved Enterprise Intrusion Detection, James J. Treinen

Electronic Theses and Dissertations

One of the greatest challenges facing network operators today is the identification of malicious activity on their networks. The current approach is to deploy a set of intrusion detection sensors (IDSs) in various locations throughout the network and on strategic hosts. Unfortunately, the available intrusion detection technologies generate an overwhelming volume of false alarms, making the task of identifying genuine attacks nearly impossible. This problem is very difficult to solve even in networks of nominal size. The task of uncovering attacks in enterprise class networks quickly becomes unmanageable.

Research on improving intrusion detection sensors is ongoing, but given the nature …

Design And Analysis Of Effective Routing And Channel Scheduling For Wavelength Division Multiplexing Optical Networks, Xingbo Gao

Electronic Theses and Dissertations

Optical networking, employing wavelength division multiplexing (WDM), is seen as the technology of the future for the Internet. This dissertation investigates several important problems affecting optical circuit switching (OCS) and optical burst switching (OBS) networks. Novel algorithms and new approaches to improve the performance of these networks through effective routing and channel scheduling are presented. Extensive simulations and analytical modeling have both been used to evaluate the effectiveness of the proposed algorithms in achieving lower blocking probability, better fairness as well as faster switching. The simulation tests were performed over a variety of optical network topologies including the ring and …

Learning Techniques For Information Retrieval And Mining In High-Dimensional Databases, Hao Cheng

Electronic Theses and Dissertations

The main focus of my research is to design effective learning techniques for information retrieval and mining in high-dimensional databases. There are two main aspects in the retrieval and mining research: accuracy and efficiency. The accuracy problem is how to return results which can better match the ground truth, and the efficiency problem is how to evaluate users' requests and execute learning algorithms as fast as possible. However, these problems are non-trivial because of the complexity of the high-level semantic concepts, the heterogeneous natures of the feature space, the high dimensionality of data representations and the size of the databases. …

Geometric Invariance In The Analysis Of Human Motion In Video Data, Yuping Shen

Electronic Theses and Dissertations

Human motion analysis is one of the major problems in computer vision research. It deals with the study of the motion of human body in video data from different aspects, ranging from the tracking of body parts and reconstruction of 3D human body configuration, to higher level of interpretation of human action and activities in image sequences. When human motion is observed through video camera, it is perspectively distorted and may appear totally different from different viewpoints. Therefore it is highly challenging to establish correct relationships between human motions across video sequences with different camera settings. In this work, we …

Water And The Mountains: Maya Water Mangement At Caracol, Belize, James Crandall

Electronic Theses and Dissertations

Water management techniques in the Southern Maya Lowlands are both regionally diverse and site specific. This thesis examines the water management strategies of the Classic Period Maya at the site of Caracol, Belize. While it is likely that elites at Caracol controlled the redistribution of resources, i.e. craft and agricultural products, it is probable that the production of agricultural resources and the maintenance of water resource acquisition took place on a more local level. In order to test this hypothesis, a sample of five reservoirs were examined through original research -- and situated in conjunction with past settlement studies -- …

New Computational Approaches For Multiple Rna Alignment And Rna Search, Daniel Deblasio

Electronic Theses and Dissertations

In this thesis we explore the the theory and history behind RNA alignment. Normal sequence alignments as studied by computer scientists can be completed in O(n2) time in the naive case. The process involves taking two input sequences and finding the list of edits that can transform one sequence into the other. This process is applied to biology in many forms, such as the creation of multiple alignments and the search of genomic sequences. When you take into account the RNA sequence structure the problem becomes even harder. Multiple RNA structure alignment is particularly challenging because covarying mutations make sequence …

Visual Inspection Of Railroad Tracks, Pavel Babenko

Electronic Theses and Dissertations

In this dissertation, we have developed computer vision methods for measurement of rail gauge, and reliable identification and localization of structural defects in railroad tracks. The rail gauge is the distance between the innermost sides of the two parallel steel rails. We have developed two methods for evaluation of rail gauge. These methods were designed for different hardware setups: the first method works with two pairs of unaligned video cameras while the second method works with depth maps generated by paired laser range scanners. We have also developed a method for detection of rail defects such as damaged or missed …

Chemical Bath Deposition Of Group Ii-Vi Semiconductor Thin Films For Solar Cells Applications, Hani Khallaf

Electronic Theses and Dissertations

Chemical bath deposition (CBD) is the analog in liquid phase of the well-known chemical vapor deposition technique in the vapor phase. In CBD, deposition of thin films takes place from aqueous solutions at low temperatures by a chemical reaction between dissolved precursors, with the help of a complexing agent. Among all techniques used to grow Group II-VI semiconductors, CBD has the advantage of being a simple, low temperature, and inexpensive large-area deposition technique. So far, its contribution in thin film solar cells industry has been mainly limited to growing n-type CdS and/or ZnS window layers for CdTe-based and CIGS-based solar …

Design, Synthesis, And Characterization Of Novel Hydrophilic Fluorene-Based Derivatives For Bioimaging Applications, Dao Nguyen

Electronic Theses and Dissertations

In this work, hydrophilic fluorene-based derivatives that contain ethylene oxide substituents, have been synthesized and characterized for potential use as new fluorophores for bioimaging applications and for fluorescence sensing of heavy metals. Symmetrical and unsymmetrical fluorene derivatives based on structural types of acceptor-pi-acceptor, acceptor-pi-donor, and donor-pi-donor were characterized by TGA, UV-vis absorption, fluorescence emission, lifetime, anisotropy, and two-photon absorption (2PA) cross section. They were found to possess high thermal stability, high photostability, high fluorescence quantum yields, and generally large two-photon absorption cross sections, making them quite suitable for new probes in single-photon absorption and two-photon absorption fluorescence microscopy imaging. Novel …

Application Of Alkylsilane Self-Assembled Monolayers For Cell Patterning And Development Of Biolocial Microelectromechanical Systems, Kerry Wilson

Electronic Theses and Dissertations

Advances in microfabrication and surface chemistry techniques have provided a new paradigm for the creation of in vitro systems for studying problems in biology and medicine in ways that were previously not practical. The ability to create devices with micro- to nano-scale dimensions provides the opportunity to non-invasively interrogate and monitor biological cells and tissue in large arrays and in a high-throughput manner. These systems hold the potential to, in time, revolutionize the way problems in biology and medicine are studied in the form of point-of-care devices, lab-on-chip devices, and biological microelectromechanical systems (BioMEMS). With new in vitro models, it …

Synthesis Of Novel Fluorene-Based Two-Photon Absorbing Molecules And Their Applications In Optical Data Storage, Microfabricatio, Ciceron Yanez

Electronic Theses and Dissertations

Two-photon absorption (2PA) has been used for a number of scientific and technological applications, exploiting the fact that the 2PA probability is directly proportional to the square of the incident light intensity (while one-photon absorption bears a linear relation to the incident light intensity). This intrinsic property of 2PA leads to 3D spatial localization, important in fields such as optical data storage, fluorescence microscopy, and 3D microfabrication. The spatial confinement that 2PA enables has been used to induce photochemical and photophysical events in increasingly smaller volumes and allowed nonlinear, 2PA-based, technologies to reach sub-diffraction limit resolutions. The primary focus of …

Theoretical And Computational Studies Of Dissociative Recombination Of H3+ With Low Kinetic Energy Electrons: Time-Independent A, Samantha Santos

Electronic Theses and Dissertations

Dissociative recombination of molecular ions by collisions with electrons is a reactive collision, in which the electronic kinetic energy is transferred to the excitation of the molecule that, then, dissociates. The goals of this dissertation was (1) to improve existing approaches in theory of DR of triatomic ions in the time-independent framework developed in recent years by Kokoouline and Greene, and (2) to develop a time-dependent theoretical framework for DR treatment based on quantum defect theory. The theoretical method developed by Kokoouline and Greene is based on multichannel quantum defect theory and accounts for the major non-Born-Oppenheimer Jahn-Teller interaction between …

Geochemical Impacts From Permanganate Oxidation Based On Field Scale Assessments., Kelly Ann Moore

Electronic Theses and Dissertations

In situ chemical oxidation (ISCO) using permanganate is a technology for treatment of organic hazardous wastes. This research is a review of 30 permanganate (MnO₄^-) ISCO sites to determine whether there are long term impacts on groundwater quality due to the introduction of the oxidant into the subsurface. A second objective is to determine if manganese concentration can be predicted by trends in specific pre and postoxidation monitored parameters (i.e., pH and oxidation reduction potential (ORP)). The final objective is to identify the effects of site and design conditions on groundwater conditions postoxidation. Results indicate that (1) …