Digital Commons Network^™

Test-Retest Reliability In The Determination Of The Speech Recognition Threshold, Alyssa Montierth Jacobs

Theses and Dissertations

For many years, speech recognition threshold (SRT) testing has been used as an indicator of audiologic health. However, with changing methods and technology, test-retest reliability has not been reviewed extensively with newer digitally recorded spondaic words which meet a published criterion of listener familiarity. This study examined the test-retest reliability of 33 high frequency usage and psychometrically equated spondaic words. The American Speech-Language-Hearing Association recommended method (2-dB decrements) was used to measure the left and right SRT of 40 participants using both male and female talker recordings. For each participant, four SRTs were found during the test condition and four …

Assessing Deployment Risk And Resiliency Factors And The Adjustment Outcomes Of Police Officers Serving In Operation Iraqi Freedom And Operation Enduring Freedom, Paula Barrows

Theses and Dissertations

ASSESSING DEPLOYMENT RISK AND RESILIENCY FACTORS AND THE ADJUSTMENT OUTCOMES OF POLICE OFFICERS SERVING IN OPERATION IRAQI FREEDOM AND OPERATION ENDURING FREEDOM By Paula Barrows Davenport, MS A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University. Virginia Commonwealth University, 2012 Director: Dr. Janet R. Hutchinson Professor and Chair of the Department of Gender, Sexuality and Women’s Studies The goal of this exploratory study was to evaluate risk and resiliency factors from the Deployment Risk and Resiliency Inventory (DRRI) in predicting post-deployment adjustment outcomes among police officers who served in …

Estimating Vo2max Using A Personalized Step Test, Catherine Webb

Theses and Dissertations

The purpose of this study was to develop a personalized step test and a valid regression model that used non-exercise data and data collected during the step test to estimate VO2max in males and females 18 to 30 years of age. All participants (N= 80) successfully completed a step test with the starting step rate and step height being determined by the self-reported perceived functional ability (PFA) score and participant's height, respectively. All participants completed a maximal graded exercise test (GXT) to measure VO2max. Multiple linear regression analysis yielded the following equation (R = 0.90, SEE = 3.43 mL/kg/min): 45.938 …

Evaluation Of The Thorax Of Manduca Sexta For Flapping-Wing Micro Air Vehicle Applications, Alex C. Hollenbeck

Theses and Dissertations

The tobacco hornworm hawkmoth (Manduca sexta) provides an excellent model from which to garner knowledge pertaining to the development of a Flapping Wing Micro Air Vehicle (FWMAV). Insect-sized FWMAVs will be used by the future warfighter for reconnaissance, nuclear/chemical/biological hazard sensing, and targeting. One of the major challenges facing FWMAV developers is the energetically demanding nature of low Reynolds flapping flight. Investigating the Manduca sexta thorax/wing flapping mechanism as a mechanical system will provide insight into its inherent efficiency. This thesis examined the energetics of the thorax under static loading and dynamic loading using an innovative load-application technique. It was …

Probabilistic Model For Laser Damage To The Human Retina, David A. Wooddell Jr.

Theses and Dissertations

Understanding how lasers interact with media during propagation is a premiere field of physics. The subject area known as laser bioeffects explores laser interactions with biological cells, tissues, organs, and bodies. This research includes laser applications used in medicine, establishes safe exposure limits for industry and academia, and generally studies the many effects of laser light on living creatures. The bioeffects community relies heavily on deterministic modeling and simulation tools to support experimental research into damage thresholds and laser effects. However, recent laser applications require a probabilistic approach to support risk management and analyses methodologies. Some probabilistic models exist, but …

Evaluation Of Municipal Wastewater Treatment Plant Activated Sludge For Biodegradation Of Propylene Glycol As An Aircraft Deicer, Justin D. Delorit

Theses and Dissertations

Aircraft deicing fluid used at airport facilities is often collected for treatment or disposal in order to prevent serious ecological threats to nearby surface waters. This study investigated lab scale degradation of propylene glycol (PG), the active ingredient in a common aircraft deicing fluid, by way of a laboratory-scale sequencing batch reactor containing municipal waste water treatment facility activated sludge (AS) performing simultaneous organic carbon oxidation and nitrification. The ability of AS to remove PG was evaluated by studying the biodegradation and sorption characteristics of PG in an AS medium. The results indicate sorption may play a role in the …

Comparative Analysis Of Two Biological Warfare Air Samplers Using Live Surrogate Agents, James C. Enderby

Theses and Dissertations

The United States Air Force has several high-volume biological air samplers, including the XMX/2L-MIL and the Biocapture 650. Limited information is available on either in terms of its collection of viruses and bacteria. However, previous research on the XMX/2L-MIL has determined that modifications to the secondary flow rate and the use of a virus preserving collection media may provide improved virus collection rates. In this thesis, these modifications were investigated to determine their impact on the collection of viral and bacterial aerosols. Additionally, relative collection rates were compared against those for the Biocapture 650. MS2 bacteriophage was the viral surrogate …

Influence Of Ph On The Transport Of Silver Nanoparticles In Saturated Porous Media: Laboratory Experiments And Modeling, Jason R. Flory

Theses and Dissertations

Given the ubiquity of silver nanoparticles (AgNPs), the largest and fastest growing category of nanomaterials, and their potential for toxic effects to both humans and the environment, it is important to understand their environmental fate and transport. The purpose of this study is to gain information on the transport properties of unmodified AgNP suspensions in a glass bead-packed column under saturated flow conditions at different solution pH levels. Commercial AgNPs were characterized using high resolution transmission spectroscopy (HRTEM), dynamic light scattering (DLS) and ultraviolet (UV) visible spectroscopy. Transport data were collected at different pH levels (4, 6.5 and 9) at …

Biodegradation Of Organophosphate Chemical Warfare Agents By Activated Sludge, Steven J. Schuldt

Theses and Dissertations

Organophosphates (OPs) have been widely used as Chemical Warfare Agents (CWAs) as well as pesticides since World War II and still remain a threat to national security. While efforts have been taken at military installations and civilian communities to secure these chemicals and prevent their misuse, a determined adversary could still obtain and deploy them to injure, kill, or instill terror. The lethal properties of this group of compounds are primarily owed to their irreversible inhibition of the enzyme acetyl cholinesterase (AChE) and thus may alter the human nervous system or affect the hormonal balance of children in particular. In …

Emissions From Simulated Open Burning Of Deployed Us Military Waste, Brian D. Woodall

Theses and Dissertations

U.S. military forces have relied primarily on open burning as an expedient method of volume reduction and treatment of solid waste during the conflicts in Afghanistan and Iraq. This study is the first effort to characterize a broad range of pollutants and their emission factors during the burning of military waste and the effects that recycling efforts, namely removing plastics, might have on emissions. Piles of simulated military waste were constructed, burned, and emissions sampled at the U.S. Environmental Protection Agency (EPA) Open Burn Testing Facility (OBTF), Research Triangle Park, NC. Three tests contained polyethylene terephthalate (PET #1 or PET) …

Acquisition Program Problem Detection Using Text Mining Methods, Trevor P. Miller

Theses and Dissertations

This research provides program analysts and Department of Defense leadership with an approach to identify problems in real-time for acquisition contracts. Specifically, we test the abilities of statistical algorithms using text mining techniques to detect unusual changes in acquisition programs’ cost estimates at the completion of the programs. Currently, the government purchases monthly written reports, an informational tool on status of an acquisition program, but has not been integrated into problem prediction analysis. We center our research on the following two questions: First, can we quantify the qualitative written reports? Second, can we use these quantifications of the texts to …

Integration, Testing And Validation, Of A Small Hybrid-Electric Remotely-Piloted Aircraft, Joseph K. Ausserer

Theses and Dissertations

Parallel hybrid-electric technology offers a wide variety of new mission capabilities including low-observable loiter operations and increased fuel efficiency for small remotely-piloted aircraft. This research focused on the integration, validation, and testing of a hybrid-electric propulsion system consisting of commercially available components to fabricate a small remotely-piloted aircraft capable of extended low-observable operation. Three novel aspects contributed to the success of the design: optimization of the propulsive components to the integrated system, torque control of the components for additive power, and a one-way bearing/ pulley mechanism (patent pending) mechanically linking the hybrid system components. To the knowledge of the author …

A Finite Element Analysis Of A Carbon Fiber Composite Micro Air Vehicle Wing, Theodore A. Szelag

Theses and Dissertations

Micro-air vehicles (MAV)s provide a valuable and low observable way to do the jobs that the Air Force deems to be dull, dirty and dangerous. Basing the design of an MAV wing on that of a biological counterpart will provide a proven design that is capable of achieving the mission requirements. This research is designed to analyze the design and manufacturing of a wing based off the Manduca Sexta.

Inaccuracies in the fiber orientation can result in substantial changes in the material properties. Experimental vibration data of composite material samples manufactured using a three-ply [0/90/0] small non-homogenous fiber composite provided …

Enhanced Image-Aided Navigation Algorithm With Automatic Calibration And Affine Distortion Prediction, Juan D. Jurado

Theses and Dissertations

This research aims at improving two key steps within the image aided navigation process: camera calibration and landmark tracking. The camera calibration step is improved by automating the point correspondence calculation within the standard camera calibration algorithm, thereby reducing the required time for calibration while maintaining the output model accuracy. The feature landmark tracking step is improved by digitally simulating affine distortions on input images in order to calculate more accurate feature descriptors for improved feature matching in high relative viewpoint change. These techniques are experimentally demonstrated in an outdoor environment with a consumer-grade inertial sensor and three imaging sensors, …

Spectral And Spatial Coherent Emission Of Thermal Radiation From Metal-Semiconductor Nanostructures, Shane N. Mcconnell

Theses and Dissertations

The spectral and spatial radiative properties of coherent thermal emission in the mid- and far-IR through the use of micro and nano-structured metal-semiconductor materials were designed and demonstrated experimentally. Using an implementation of the Rigorous Coupled Wave Analysis and Computer Simulation Technology (CST), two structures were designed to selectively emit at mid- and far-IR wavelengths, a 1-D truncated multilayer resonator and a 3-D hybrid photonic crystal (PC)-multilayer. A High Impulse Power Magnetron Sputtering (HIPIMS) deposition technique was used to fabricate two silver-germanium-silver (Ag-Ge-Ag) resonating structures with layer thicknesses of 6-240-160 nm for one sample and 6-700-200 nm for the other. …

Local Histograms For Per-Pixel Classification, Melody L. Massar

Theses and Dissertations

We introduce a rigorous mathematical theory for the analysis of local histograms, and study how they interact with textures that can be modeled as occlusions of simpler components. We first show how local histograms can be computed as a system of convolutions and discuss some basic local histogram properties. We then introduce a probabilistic, occlusion-based model for textures and formally demonstrate that local histogram transforms are natural tools for analyzing the textures produced by our model. Next, we characterize all nonlinear transforms which satisfy the three key properties of local histograms and consider the appropriateness of local histogram features in …

The Effectiveness Of Using Diversity For Selecting Multiple Classifier Systems, Harris K. Butler

Theses and Dissertations

A wealth of approaches exists to perform classification of items of interest. The goal of fusion techniques is to exploit complementary approaches and merge the information provided by these methods to provide a solution superior than any single method. Associated with choosing a fusion algorithm is the choice of algorithm or algorithms that will be fused. This decision is most often referred to as ensemble selection. Historically classifier ensemble accuracy has been used to accomplish this task. More recently research has focused on creating and evaluating diversity metrics to more effectively select ensemble members. This research focuses on the use …

Analysis Of Social Network Measures With Respect To Structural Properties Of Networks, Joshua D. Guzman

Theses and Dissertations

Social Network Analysis (SNA), the study of social interactions within a group, spans many different fields of study, ranging from psychology to biology to information sciences. Over the past half century, many analysts outside of the social science field have taken SNA concepts and theories and have applied them to an array of networks in the hope of formulating mathematical descriptions of the relations within the network of interest. More than 50 measures of networks have been identified across these fields; however, little research has examined the findings of these measures for possible relationships. This thesis tests a set of …

Detector Design Considerations In High-Dimensional Artificial Immune Systems, Jason M. Bindewald

Theses and Dissertations

This research lays the groundwork for a network intrusion detection system that can operate with only knowledge of normal network traffic, using a process known as anomaly detection. Real-valued negative selection (RNS) is a specific anomaly detection algorithm that can be used to perform two-class classification when only one class is available for training. Researchers have shown fundamental problems with the most common detector shape, hyperspheres, in high-dimensional space. The research contained herein shows that the second most common detector type, hypercubes, can also cause problems due to biasing certain features in high dimensions. To address these problems, a new …

Towards Quantifying Programmable Logic Controller Resilience Against Intentional Exploits, Henry W. Bushey

Theses and Dissertations

Supervisory Control and Data Acquisition (SCADA) systems control and monitor services for the nation's critical infrastructure. Recent cyber induced events (e.g., Stuxnet) provide an example of a targeted, covert cyber attack against a SCADA system that resulted in physical effects. Of particular note is how Stuxnet exploited the trust relationship between the human machine interface (HMI) and programmable logic controllers (PLCs). Current methods for validating system operating parameters rely on message exchange and network communications protocols, generally observed at the HMI. Although sufficient at the macro level, this method does not provide detection of malware that exhibits physical effects via …

Prototyping The Use Of Dispersion Models To Predict Ground Concentrations During Burning Of Deployed Military Waste, Val Oppenheimer

Theses and Dissertations

United States military forces in Iraq and Afghanistan have often used open burning of solid waste as a means to achieve volume reduction and to minimize vector borne illnesses. Assessing exposures to burn pit emissions has proven challenging, requiring significant numbers of personnel and sampling equipment. This study examined the use of three common dispersion models to determine the feasibility of using software modeling to predict short-range exposures to burn pit emissions, in lieu of sole reliance on ground sampling. Four open burn tests of municipal solid waste were conducted at Tooele Army Depot, Utah. Aerial samples were collected above …

Stabilizing Acetylcholinesterase On Carbon Electrodes Using Peptide Nanotubes To Produce Effective Biosensors, Todd J. Stevens

Theses and Dissertations

A biosensor for the detection of organophosphates in water was created by immobilizing acetylcholinesterase (AChE) on a carbon screen printed electrode using peptide nanotubes (PNT) and Nafion®. This sensor was used with acetylthiocholine (ASCh) substrate to detect the inhibitory effects of malathion. The stability of the encapsulated enzyme was measured over 50 days of storage at 4°C in a phosphate buffer solution. The oxidation of thiocholine, a product of the enzymatic reaction of ASCh and AChE, was used to measure the activity of the encapsulated enzyme. Cyclic voltammograms were taken in an ASCh and phosphate buffer solution, and the peak …

Computer Aided Multi-Data Fusion Dismount Modeling, Juan L. Morales

Theses and Dissertations

Recent research efforts strive to address the growing need for dismount surveillance, dismount tracking and characterization. Current work in this area utilizes hyperspectral and multispectral imaging systems to exploit spectral properties in order to detect areas of exposed skin and clothing characteristics. Because of the large bandwidth and high resolution, hyperspectral imaging systems pose great ability to characterize and detect dismounts. A multi-data dismount modeling system where the development and manipulation of dismount models is a necessity. This thesis demonstrates a computer aided multi-data fused dismount model, which facilitates studies of dismount detection, characterization and identification. The system is created …

My Identity, Kris Cho

Theses and Dissertations

My identity is the dominate theme in my works. As a Korean American, I am influenced by life experiences in both countries. These two vastly different cultures and experiences define me as an individual. I use references and symbolism from both cultures as elements in my painting, mixed media, and crafts. I have spent half of my life in Korea, my mother country, and the other half in America, my new homeland. Living as an American, my artworks keep me connected to my Korean roots. Creating artwork is my way to relay who I really am as a Korean American.

The Phylogeography Of The Mountain Sucker [Catostomus (Pantosteus) Platyrhynchus], Nina Johanna Laitnen

Theses and Dissertations

Pantosteus, a subgenus of Catostomus, includes the mountain sucker (Catostomus playthyrnchus), whose speculated older origins in the Miocene/Pliocene can provide insight into the ancient geographical events of western North America. We believe that major geologic events influencing the diversification of mountain suckers include the rise of the Colorado Plateau, the connections between the ancient Snake River system and the Lahontan system and subsequently the connection of the Snake River system to the Columbia Basin, dispersal of mountain suckers across the continental divide, as well as the Pleistocene Bonneville flood. If this is true, we should see …

Prediction Of Respiratory Motion, Suk Jin Lee

Theses and Dissertations

Radiation therapy is a cancer treatment method that employs high-energy radiation beams to destroy cancer cells by damaging the ability of these cells to reproduce. Thoracic and abdominal tumors may change their positions during respiration by as much as three centimeters during radiation treatment. The prediction of respiratory motion has become an important research area because respiratory motion severely affects precise radiation dose delivery. This study describes recent radiotherapy technologies including tools for measuring target position during radiotherapy and tracking-based delivery systems. In the first part of our study we review three prediction approaches of respiratory motion, i.e., model-based methods, …

Respite Care And Marital Quality: Families With A Child Diagnosed With An Autism Spectrum Disorder, Amber Rachelle Harper

Theses and Dissertations

Parents of children with an autism spectrum disorder (ASD) are at greater risk than other couples for having higher stress levels and lower marital quality. Respite care has been suggested as a way to help alleviate stress. This study investigated the relationship between respite care and marital quality; and the potential of mother stress and father stress as mediating variables. One hundred and one couples, each consisting of a mother and a father who lived with their child with an ASD, were given questionnaires including a respite questionnaire, Revised Dyadic Adjustment Scale, Experience in Close Relationships Questionnaire, and …

Indexing And Dialectical Transcendence: Kenneth Burke's Critical Method, David Erland Isaksen

Theses and Dissertations

Kenneth Burke has been described as arguably the most important rhetorician and critical theorist of the twentieth century, and yet an important part of his scholarship has been generally overlooked by the academic community. The pentad has become the most prominent "Burkean" framework for analyzing texts, yet Kenneth Burke himself preferred "a more direct" way of approaching texts which he named "indexing." This thesis recreates this method from the pieces found in his scholarly writing, personal correspondence, and the papers his students produced for the class he taught at Bennington College. Kenneth Burke believed indexing could uncover the "pattern of …

Rhetoric In Dialectical Behavior Therapy: Healing Minds Through Argumentation, Celeste Lloyd Zsembery

Theses and Dissertations

The fields of psychology and rhetoric share the goal of improving human mental health and behavior through persuasion. This thesis traces the history of rhetoric and psychology theory, focusing on the parallel theories of Nienkamp's internal rhetoric and Herman's dialogical self. Both theories model the human mind as having multiple psyches that actively interact to interpret human experience and project human behavior. I conclude with a case study of anorexic patients using ethos, pathos, and logos in dialectical behavior therapy (DBT), arguing that principles of rhetoric can help patients with mental disorders cognitively realign their thinking more effectively than drug …

Effects Of Predation Environment And Food Availability On Somatic Growth In The Livebearing Fish Brachyrhaphis Rhabdophora (Pisces: Poeciliidae), Brittany Herrod Gale

Theses and Dissertations

Variation in somatic growth rates has interested biologists for decades because of the relationship between growth and other fitness-determining traits (i.e. fecundity, survival, and body size), and the corresponding effect of somatic growth on production of organisms humans use for food. The interaction between genetic variation in growth rates and environmentally induced variation in growth rates shows the pattern of growth across multiple environments (i.e. the reaction norm) that clarifies the history and potential future of evolutionary change in growth rates among populations. Theoretical predictions suggest variation in predator-induced mortality rates can influence mean growth rates and the shape of …