Physical Sciences and Mathematics Commons^™

Hierarchies For Event-Based Modeling Of Geographic Phenomena, Rui Zhang

Electronic Theses and Dissertations

Modeling the dynamic aspect, or change, of geographic phenomena is essential to explain the evolution of geographic entities and predict their future. Event-based modelling, describing the occurrences rather than states of geographic phenomena, gives an explicit treatment of such change, but currently does not have the support of the mechanisms to enable the shifts among different granularities of events. To account for different tasks, a hierarchical representation of the event space at different granularities is needed.

This thesis presents an event-based model; a general framework for representing events based on precondition and postcondition using Allen's temporal interval logic. It captures …

Climatic And Lithogenic Controls On Soil Organic Matter-Mineral Associations, Rota Wagai

Electronic Theses and Dissertations

Interactions of organic matter (OM) with soil mineral phases strongly affect the storage and dynamics of soil OM as well as other ecosystem processes. This study examined aspects of organo-mineral associations in soils at different scales. First, I assessed the potential controls of climate and parent rock type on organo-mineral associations using two sets of undisturbed tropical forest soils developed on two contrasting rocks along an altitudinal gradient in Borneo, Southeast Asia. Density fractionations showed that OM stored in surface mineral soils partitioned towards plant detritus fraction under cooler climates on both rock types. Thus climate exerted stronger control on …

Enhancing Message Privacy In Wired Equivalent Privacy., Darshan Purandare

Electronic Theses and Dissertations

The 802.11 standard defines the Wired Equivalent Privacy (WEP) and encapsulation of data frames. It is intended to provide data privacy to the level of a wired network. WEP suffered threat of attacks from hackers owing to certain security shortcomings in the WEP protocol. Lately, many new protocols like WiFi Protected Access (WPA), WPA2, Robust Secure Network (RSN) and 802.11i have come into being, yet their implementation is fairly limited. Despite its shortcomings one cannot undermine the importance of WEP as it still remains the most widely used system and we chose to address certain security issues and propose some …

An Introduction To Hellmann-Feynman Theory, David Wallace

Electronic Theses and Dissertations

The Hellmann-Feynman theorem is presented together with certain allied theorems. The origin of the Hellmann-Feynman theorem in quantum physical chemistry is described. The theorem is stated with proof and with discussion of applicability and reliability. Some adaptations of the theorem to the study of the variation of zeros of special functions and orthogonal polynomials are surveyed. Possible extensions are discussed.

Graph-Theoretic Approach To Modeling Propagation And Control Of Network Worms, Zoran Nikoloski

Electronic Theses and Dissertations

In today's network-dependent society, cyber attacks with network worms have become the predominant threat to confidentiality, integrity, and availability of network computing resources. Despite ongoing research efforts, there is still no comprehensive network-security solution aimed at controling large-scale worm propagation. The aim of this work is fivefold: (1) Developing an accurate combinatorial model of worm propagation that can facilitate the analysis of worm control strategies, (2) Building an accurate epidemiological model for the propagation of a worm employing local strategies, (3) Devising distributed architecture and algorithms for detection of worm scanning activities, (4) Designing effective control strategies against the worm, …

Affective Design In Technical Communication, Michael Alan Rosen

Electronic Theses and Dissertations

Traditional human-computer interaction (HCI) is based on 'cold' models of user cognition; that is, models of users as purely rational beings based on the information processing metaphor; however, an emerging perspective suggests that for the field of HCI to mature, its practitioners must adopt models of users that consider broader human needs and capabilities. Affective design is an umbrella term for research and practice being conducted in diverse domains, all with the common thread of integrating emotional aspects of use into the creation of information products. This thesis provides a review of the current state of the art in affective …

The Scintillation Index In Moderate To Strong Turbulence For The Gaussian Beam Wave Along A Slant Path, Fredrick Eugene Thomas

Electronic Theses and Dissertations

Scintillation is one of the most common statistics in the literature of mathematical modeling of laser propagation through random media. One approach to estimating scintillation is through the Rytov approximation, which is limited to weak atmospheric turbulence. Recently, an improvement of the Rytov approximation was developed employing a linear filter function technique. This modifies the Rytov approximation and extends the validity into the moderate to strong regime. In this work, an expression governing scintillation of a Gaussian beam along an uplink slant path valid in all regimes of turbulence is presented, as well as results for the limiting cases of …

Decision Theory Classification Of High-Dimensional Vectors Based On Small Samples, David Bradshaw

Electronic Theses and Dissertations

In this paper, we review existing classification techniques and suggest an entirely new procedure for the classification of high-dimensional vectors on the basis of a few training samples. The proposed method is based on the Bayesian paradigm and provides posterior probabilities that a new vector belongs to each of the classes, therefore it adapts naturally to any number of classes. Our classification technique is based on a small vector which is related to the projection of the observation onto the space spanned by the training samples. This is achieved by employing matrix-variate distributions in classification, which is an entirely new …

Insulator-Insulator Contact Charging As A Function Of Pressure, Michael Hogue

Electronic Theses and Dissertations

Metal - metal and to an extent metal - insulator contact or triboelectric charging are well known phenomena with good theoretical understanding of the charge exchange mechanism. However, insulator – insulator charging is not as well understood. Theoretical and experimental research has been performed that shows that the surface charge on an insulator after triboelectric charging with another insulator is rapidly dissipated with lowered atmospheric pressure. This pressure discharge is consistent with surface ions being evaporated off the surface once their vapor pressure falls below the saturation vapor pressure. A two-phase equilibrium model based on an ideal gas of singly …

Reaction Rates For The Dehalogenation Of Trichloroethylene Using Various Types Of Zero-Valent Iron, Neil Stewart

Electronic Theses and Dissertations

Remediation of trichloroethylene (TCE) and other chlorinated solvents is of great concern due to their toxicity and their persistence in the environment. Iron has been used extensively in the past decade as a subsurface reactive agent for the remediation of dense, nonaqueous-phase liquids (DNAPLs). Permeable reactive barrier walls (PRBW) have been installed at many sites around the country to treat contaminated plumes resulting from the presence of DNAPL pools. The use of zero-valent metals, such as iron, to effectively reductively dechlorinate DNAPLs has been employed as the reactive material in these PRBWs (Gillham et al., 1993). However, limited work has …

Contributions To Automatic Particle Identification In Electron Micrographs: Algorithms, Implementation, And Applications, Vivek Singh

Electronic Theses and Dissertations

Three dimensional reconstruction of large macromolecules like viruses at resolutions below 8 Ã… - 10 Ã… requires a large set of projection images and the particle identification step becomes a bottleneck. Several automatic and semi-automatic particle detection algorithms have been developed along the years. We present a general technique designed to automatically identify the projection images of particles. The method utilizes Markov random field modelling of the projected images and involves a preprocessing of electron micrographs followed by image segmentation and post processing for boxing of the particle projections. Due to the typically extensive computational requirements for extracting hundreds of …

Refractive Indices Of Liquid Crystals And Their Applications In Display And Photonic Devices, Jun Li

Electronic Theses and Dissertations

Liquid crystals (LCs) are important materials for flat panel display and photonic devices. Most LC devices use electrical field-, magnetic field-, or temperature-induced refractive index change to modulate the incident light. Molecular constituents, wavelength, and temperature are the three primary factors determining the liquid crystal refractive indices: ne and no for the extraordinary and ordinary rays, respectively. In this dissertation, we derive several physical models for describing the wavelength and temperature effects on liquid crystal refractive indices, average refractive index, and birefringence. Based on these models, we develop some high temperature gradient refractive index LC mixtures for photonic applications, such …

Multizoom Activity Recognition Using Machine Learning, Raymond Smith

Electronic Theses and Dissertations

In this thesis we present a system for detection of events in video. First a multiview approach to automatically detect and track heads and hands in a scene is described. Then, by making use of epipolar, spatial, trajectory, and appearance constraints, objects are labeled consistently across cameras (zooms). Finally, we demonstrate a new machine learning paradigm, TemporalBoost, that can recognize events in video. One aspect of any machine learning algorithm is in the feature set used. The approach taken here is to build a large set of activity features, though TemporalBoost itself is able to work with any feature set …

Structural Study Of Disease Related Proteins, Ayse Sinem Ozyurt

Electronic Theses and Dissertations

The availability of complete sequences for the genomes of many organisms changes the researcher's attention from genome sequencing to finding the function of gene products, the proteins. The three dimensional (3D) structure of a protein is helpful to understand its function, because tertiary structure is more conserved in evolution than sequence. The 3D structures can be found quickly by using high-throughput (HT) methods for protein expression, purification, characterization and structure determination. This process is very challenging in every step. Therefore we selected nearly 200 cancer related proteins as targets to see the difficulties in trying to determine the web predicted …

Voice Authenticationa Study Of Polynomial Representation Of Speech Signals, John Strange

Electronic Theses and Dissertations

A subset of speech recognition is the use of speech recognition techniques for voice authentication. Voice authentication is an alternative security application to the other biometric security measures such as the use of fingerprints or iris scans. Voice authentication has advantages over the other biometric measures in that it can be utilized remotely, via a device like a telephone. However, voice authentication has disadvantages in that the authentication system typically requires a large memory and processing time than do fingerprint or iris scanning systems. Also, voice authentication research has yet to provide an authentication system as reliable as the other …

Session-Based Intrusion Detection System To Map Anomalous Network Traffic, Bruce Caulkins

Electronic Theses and Dissertations

Computer crime is a large problem (CSI, 2004; Kabay, 2001a; Kabay, 2001b). Security managers have a variety of tools at their disposal -- firewalls, Intrusion Detection Systems (IDSs), encryption, authentication, and other hardware and software solutions to combat computer crime. Many IDS variants exist which allow security managers and engineers to identify attack network packets primarily through the use of signature detection; i.e., the IDS recognizes attack packets due to their well-known "fingerprints" or signatures as those packets cross the network's gateway threshold. On the other hand, anomaly-based ID systems determine what is normal traffic within a network and reports …

Interferometry-Based Free Space Communication And Information Processing, Muzamil Arshad Arain

Electronic Theses and Dissertations

This dissertation studies, analyzes, and experimentally demonstrates the innovative use of interference phenomenon in the field of opto-electronic information processing and optical communications. A number of optical systems using interferometric techniques both in the optical and the electronic domains has been demonstrated in the filed of signal transmission and processing, optical metrology, defense, and physical sensors. Specifically it has been shown that the interference of waves in the form of holography can be exploited to realize a novel optical scanner called Code Multiplexed Optical Scanner (C-MOS). The C-MOS features large aperture, wide scan angles, 3-D beam control, no moving parts, …

Spectral Signature Modification By Application Of Infrared Frequency-Selective Surfaces, Brian Monacelli

Electronic Theses and Dissertations

It is desirable to modify the spectral signature of a surface, particularly in the infrared (IR) region of the electromagnetic spectrum. To alter the surface signature in the IR, two methods are investigated: thin film application and antenna array application. The former approach is a common and straightforward incorporation of optically-thin film coatings on the surface designated for signature modification. The latter technique requires the complex design of a periodic array of passive microantenna elements to cover the surface in order to modify its signature. This technology is known as frequency selective surface (FSS) technology and is established in the …

Part I : Isolation Of Dipentyl 2-(4-(Pentan-3-Yl) Phenyl) Malonate From Sanguisorba Officinalis Labill Part Ii: Synthesis Of A Novel Family Of Ethers Of Podocarpic Acid, Manjeera Yalavarty

Electronic Theses and Dissertations

The goal of part I of this thesis was to isolate pure anti cancer compounds from the Russian plant Sanguisorba officinalis. This plant was selected for investigation because it showed 100% activity against leukemia (L1210 mouse leukemia cells) during the preliminary screening of approximately 100 Russian plant extracts. This work has resulted in the isolation of novel compound 11 using traditional chromatography techniques. Compound 11 was characterized with spectroscopic techniques such as IR, 1H NMR, 13C NMR, DEPT, DQCOSY and MS. Compound 11 was assigned the structure dipentyl 2-(4-(pentan-3-yl) phenyl) malonate. The goal of part II of this thesis was …

Response Of Vegetation And Endangered Waterbirds To Habitat Management Techniques At Kealia Pond National Wildlife Refuge, James Andrew Rader

Electronic Theses and Dissertations

Habitat selection, reproductive effort, and habitat utilization of Hawai’ian stilts (Himantopus mexicanus knudseni) and Hawai’ian coots (Fulica alai) was studied on Kealia Pond National Wildlife Refuge in Mau’i, Hawai’i. Nesting behavior was confirmed following management treatments on the northern shore of Kealia Pond. Nests were dispersed or randomly spaced within vegetation patches or newly created mudflat habitat. Pickleweed and makai were the dominant vegetation surrounding the nest setting and utilized for nest substrate by Hawai’ian stilts and Hawai’ian coots respectively. Mechanical control treatments were implemented through monotypic stands of pickleweed to increase interspersion of open water and promote native vegetation. …

Application Of Statistical Methods In Risk And Reliability, Astrid Heard

Electronic Theses and Dissertations

The dissertation considers construction of confidence intervals for a cumulative distribution function F(z) and its inverse at some fixed points z and u on the basis of an i.i.d. sample where the sample size is relatively small. The sample is modeled as having the flexible Generalized Gamma distribution with all three parameters being unknown. This approach can be viewed as an alternative to nonparametric techniques which do not specify distribution of X and lead to less efficient procedures. The confidence intervals are constructed by objective Bayesian methods and use the Jeffreys noninformative prior. Performance of the resulting confidence intervals is …

Utilization Of Total Mass As A Control In Diffusion Processes, Mohamed Salman

Electronic Theses and Dissertations

As motivation for the mathematical problems considered in this work, consider a chamber in the form of a long linear transparent tube. We allow for the introduction or removal of material in a gaseous state at the ends of the tube. The material diffuses throughout the tube with or without reaction with other materials. By illuminating the tube on one side with a light source with a frequency range spanning the absorption range for the material and collecting the residual light that passes through the tube with photo-reception equipment, we can obtain a measurement of the total mass of material …

Deriving The Density Of States For Granular Contact Forces, Philip Metzger

Electronic Theses and Dissertations

The density of single grain states in static granular packings is derived from first principles for an idealized yet fundamental case. This produces the distribution of contact forces P_f(f) in the packing. Because there has been some controversy in the published literature over the exact form of the distribution, this dissertation begins by reviewing the existing empirical observations to resolve those controversies. A method is then developed to analyze Edwards' granular contact force probability functional from first principles. The derivation assumes Edwards' flat measure -- a density of states (DOS) that is uniform within the metastable regions of phase space. …

Monte Carlo Simulation Of Hole Transport And Terahertz Amplification In Multilayer Delta Doped Semiconductor Structures, Maxim Dolguikh

Electronic Theses and Dissertations

Monte Carlo method for the simulation of hole dynamics in degenerate valence subbands of cubic semiconductors is developed. All possible intra- and inter-subband scattering rates are theoretically calculated for Ge, Si, and GaAs. A far-infrared laser concept based on intersubband transitions of holes in p-type periodically delta-doped semiconductor films is studied using numerical Monte-Carlo simulation of hot hole dynamics. The considered device consists of monocrystalline pure Ge layers periodically interleaved with delta-doped layers and operates with vertical or in-plane hole transport in the presence of a perpendicular in-plane magnetic field. Inversion population on intersubband transitions arises due to light hole …

In Situ Remediation Of Heavy Metal Contaminated Sediments Using Emulsified Zero-Valent Metal Particles, Kristen Marie Milum

Electronic Theses and Dissertations

Sediments can act as both a sink for pollutants and a source for aquatic contaminants. Natural and human disturbances of the sediments can release the contaminants to the overlying water where bottom dwelling, or benthic, organisms may be exposed through direct contact, ingestion of sediment particles, or uptake of dissolved contaminants present in the water. Dredging, the most common remediation technology for heavy metals, exacerbates this process. The in situ use of emulsified metal has been studied for its ability to pull heavy metals from aqueous solution and from saturated soils. It has proven successful in the laboratory with removal …

The Use And Development Of Laser Microdissection To Separate Spermatozoa From Epithelial Cells For Str Analysis, Christine Sanders

Electronic Theses and Dissertations

Short Tandem Repeat (STR) analysis has become a valuable tool in identifying the source of biological stains, particularly from the investigation of sexual assault crimes. Difficulties in analysis arise primarily in the interpretation of mixed genotypes when cell separation of the sexual assailant's sperm from the victim's cells is incomplete. The forensic community continues to seek improvements in cell separation methods from mixtures for DNA typing. This report describes the use of laser microdissection (LMD) for the separation of pure populations of spermatozoa from two-donor cell mixtures. In this study, cell separation was demonstrated by microscopic identification of histologically stained …

Synthesis, Characterizations, And Evaluation Of New Reactive Two-Photon Absorbing Dyes For Two-Photon Excited Fluorescence Imaging Applications, Katherine J. Hales

Electronic Theses and Dissertations

Recent, cooperative advances in chemistry, biology, computing, photophysics, optics, and microelectronics have resulted in extraordinary developments in the biological sciences, resulting in the emergence of a novel area termed 'biophotonics'. The integrative and interdisciplinary nature of biophotonics cuts across virtually all disciplines, extending the frontiers of basic cellular, molecular, and biology research through the clinical and pharmaceutical industries. This holds true for the development and application of the novel imaging modality utilizing multiphoton absorption and its extraordinary contribution to recent advances in bioimaging. Intimately involved in the revolution of nonlinear bioimaging has been the development of optical probes for probing …

Scene Monitoring With A Forest Of Cooperative Sensors, Omar Javed

Electronic Theses and Dissertations

In this dissertation, we present vision based scene interpretation methods for monitoring of people and vehicles, in real-time, within a busy environment using a forest of co-operative electro-optical (EO) sensors. We have developed novel video understanding algorithms with learning capability, to detect and categorize people and vehicles, track them with in a camera and hand-off this information across multiple networked cameras for multi-camera tracking. The ability to learn prevents the need for extensive manual intervention, site models and camera calibration, and provides adaptability to changing environmental conditions. For object detection and categorization in the video stream, a two step detection …

Simulation Studies Of Self-Assembly And Phase Diagram Of Amphiphilic Molecules, Geuorgui Kostadinov Bourov

Electronic Theses and Dissertations

The aim of this dissertation is to investigate self-assembled structures and the phase diagram of amphiphilic molecules of diverse geometric shapes using a number of different computer simulation methods. The semi-realistic coarse-grained model, used extensively for simulation of polymers and surfactant molecules, is adopted in an off-lattice approach to study how the geometric structure of amphiphiles affects the aggregation properties. The results of simulations show that the model system behavior is consistent with theoretical predictions, experiments and lattice simulation models. We demonstrate that by modifying the geometry of the molecules, self-assembled aggregates are altered in a way close to theoretical …

Assessment And In Vitro Repair Of Damaged Dna Templates From Forensic Stains, Ashley Hall

Electronic Theses and Dissertations

DNA extracted from biological stains is often intractable to analysis. This may due to a number of factors including a low copy number (LCN) of starting molecules, the presence of soluble inhibitors or damaged DNA templates. Remedies may be available to the forensic scientist to deal with LCN templates and soluble inhibitors but none presently exist for damaged DNA. In fact, only recently has the biochemical nature, the extent of DNA damage in physiological stains and the point at which the damage inflicted upon a particular sample precludes the ability to obtain a genetic profile for purposes of identification been …