Digital Commons Network^™

Keywords In The Post-Mechanic Codex, Davin Heckman, Matthew Wolf-Meyer

Reconstruction: Studies in Contemporary Culture

No abstract provided.

The Effects Of Visual Cues And Interstimulus Interval On Error Rates In Auditory Localization And Detection, Joseph Thomas Coyne

Psychology Theses & Dissertations

Auditory localization is an increasingly important topic as the technology for audio displays is becoming more available. However, few studies examine the effects of multiple simultaneous distracters on auditory detection and localization performance. Previous research has found that detection and localization performance significantly drops as the number of distracters increases; however, it is not clear what causes these errors. Six loudspeakers were arranged in a semicircle, and participants either had to localize an auditory stimulus or detect an auditory stimulus among multiple distracters. Participants' response time and accuracy were recorded for each trial. The number of detection errors was equivalent …

A Study Of Radiofrequency Effects On Gene Expression, Elizabeth A. Coln

Electrical & Computer Engineering Theses & Dissertations

Numerous studies have been completed over the past several years to look at the non-thermal effects of low-level radiofrequency exposure on biological systems. These studies were done to determine if exposure to radiofrequency fields are safe, or if they may lead to health problems or changes to any of the biological processes continually occurring within the human body. Responses measured include stress responses (I), gene expression (2), cell proliferation (3), cell morphology (4), and changes in DNA (5).

Dispersion is the most common model for explaining the electric behavior of biomaterials. It refers to the corresponding frequency domain concept of …

Major Factors That Influence The Employment Decisions Of Generation X Consulting Engineers, Robert William Mayfield

Engineering Management & Systems Engineering Theses & Dissertations

The purpose of this research was to study Generation X consulting engineers (those born between the years 1964 and 1980) in Lynchburg, Virginia, to determine the major factors that influence their employment decisions. Engineering consulting firms throughout the United States, particularly those in Lynchburg, have struggled to recruit young engineers in recent years. The recruiting of young engineers has been regarded by managers and executives as the single greatest challenge to the consulting profession. Despite the consensus within the profession that the problem existed, recommended solutions have been mostly speculative in nature and unsubstantiated by supportive data. This study focused …

Improvements In Wavelength Modulation Spectroscopy Using Ratios Of Higher Harmonics, James Michael Barrington

Electrical & Computer Engineering Theses & Dissertations

Experiments in Wavelength Modulation Spectroscopy have been conducted at Old Dominion University since 1996. The method provides a highly sensitive, nonintrusive method of probing gases. Research has concentrated on effectively modeling the higher harmonic shapes that are measured experimentally. Accurately modeling these signals will result in the ability to reliably extract the information contained in transition line shapes.

In order to accurately depict the signals, the theory must be thoroughly understood. This thesis develops the theory of Wavelength Modulation Spectroscopy from two aspects: a direct Fourier series expansion of a time varying intensity profile and through communication theory. In addition, …

Embedded Software Programming To Develop A Command Line User Interface For Monitoring And Debugging A Manually Driven Gas Regulator Control System, Syed N. Hyder

Electrical & Computer Engineering Theses & Dissertations

This thesis presents a complete embedded programming model and software codes for a command-line user interface for CONCOA's gas regulator control system. Control Corporation of America (CONCOA) manufactures high-pressure gas regulators, which mechanically control the pressure at their outlets. Since the control system is based on mechanical regulators, adding or stopping gas flow from the system can cause manifold fluctuation that could further cause the pressure to rise or fall with time. The main motivation for developing a command line user interface is to provide a centralized computer control to monitor and debug the gas regulator control system electronically by …

Traffic Simulation Using Arena, Shanti Yelamanchi

Electrical & Computer Engineering Theses & Dissertations

Many traffic simulation tools exist for developing traffic simulations; these tools can be divided broadly into two categories — macro simulation tools and micro simulation tools. These two categories of simulation tools are directed at modeling the extremes of traffic systems: very large systems and very small systems. There is a class of intermediate-sized transportation networks for which neither category of simulation tools might perform adequately. Additionally these specialized traffic simulation tools have a high learning curve. For developing medium sized traffic simulations in a short period of time, one might choose to use a familiar general-purpose discrete event simulation …

Variables Associated With A Sense Of Classroom Community And Academic Persistence In An Urban Community College Online Setting, Cynthia P. Cadieux

Theses and Dissertations in Urban Services - Urban Education

No abstract provided.

A Formal Object Model For Layered Networks To Support Verification And Simulation, Rasha M. B. E. Morsi

Electrical & Computer Engineering Theses & Dissertations

This work presents an abstract formal model of the interconnection structure of the Open Systems Interconnection Reference Model (OSI-RM) developed using Object-Oriented modeling principles permitting it to serve as a re-usable platform in supporting the development of simulations and formal methods applied to layered network protocols. A simulation of the object model using MODSIM III was developed and Prototype Verification System (PVS) was used to show the applicability of the object model to formal methods by formally specifying and verifying a Global Systems for Mobile communications (GSM) protocol. This application has proved to be successful in two aspects. The first …

Modeling Aspects Of Magnetic Actuators And Magnetic Suspension Systems, V. Dale Bloodgood Jr.

Mechanical & Aerospace Engineering Theses & Dissertations

This dissertation is a study of new modeling techniques developed for magnetic suspension systems. The techniques discussed are modifications of magnetic circuit theory and fundamental eddy current models. The techniques are compared against experimental test results and finite element data. The information gained from the experimental testing is used to provide insight into magnetic bearing design.

A small-gap modeling technique called extended circuit theory is developed that incorporates information about the system gained from finite element data, or experimental data, to be included in the analytic model. The variations between the classical magnetic circuit model and the finite element model …

Chipping Away At The Gendered Wall Implications For Being A Woman Sociologist, Rebecca Fogerty Grove

Sociology & Criminal Justice Theses & Dissertations

The purpose of this study was to investigate what factors may determine productivity among sociology professors and factors that-affect promotions and hiring. In today's academic institutions, the gender barrier is considered nonexistent; however, the actual existence of the gender barrier is often apparent in departmental hiring decisions and university tenure policies. With knowledge of current, often subtle, biased standards, the gender barrier can begin to be dismantled to offer true equality for all potential and current professors. The data was collected in 2001, during the fall academic semester from departments of sociology (n=2 l 8). This thesis looks at the …

Analysis Of A Direct Expansion Solar-Assisted Heat Pump Using Different Refrigerants, Francis Benjamin Gorozabel Chata

Mechanical & Aerospace Engineering Theses & Dissertations

A direct expansion solar-assisted heat pump, the components of which are properly matched for a specified ambient condition characterized by geographical location, has been analyzed. The steady state energy equation across the collector is solved for several refrigerants for two configurations; bare collector and one-cover collector. The REFPROP computer program, developed by the National Institute of Science and Technology, is used to predict refrigerant properties that are used in the steady state energy balance. The thermal performance as characterized by the coefficient of performance (COPn) is determined for a variety of refrigerants. A graphical procedure is developed for sizing of …

The Effect Of Temperature On The Optical Absorptive And Reflective Behavior Of Metals, Thomas A. Hunyady

Mechanical & Aerospace Engineering Theses & Dissertations

In the five decades since its invention, the laser has been used to commercially process materials in an increasingly diverse number of ways. The precise control over the delivery of the incident energy that is afforded by a laser allows for a wide variety of applications. All of these processes depend in some way on two important physical properties of the material being treated. These properties are known as the optical reflectivity and absorptivity of a material. The values of each of these properties are different for each material and are influenced by a number of factors, including surface roughness, …

Leadership: The Missing Variable In The Economic Development Of Sub-Saharan Africa, Osei K. Bonsu

Graduate Program in International Studies Theses & Dissertations

Contemporary economic theories, modernization and dependency, have overlooked the fact that the development process depends on the interaction of social factors. Specifically, the theories have ignored the role of leadership in analyzing economic development. This dissertation seeks to incorporate the importance of leadership into the analysis of development. It argues that sub-Saharan African countries have not developed economically because leaders in the region have been less than successful in establishing a culture conducive to industrialization. African leaders have failed to establish the high moral and scientific cultures necessary to promote economic progress. In place of those cultural attributes, the leaders …

Association Of 3d Visualization With Discrete Event Simulation, Krishna Chaitanya Kunam

Electrical & Computer Engineering Theses & Dissertations

Three-dimensional visualization provides simulation users with imagery that is closely related to their direct human experience. 3D visualization of simulations therefore has several advantages: it assists the developer in verifying and debugging the simulation; it often aids the analyst in gaining a better understanding of system performance; and it is especially important in explaining simulation results to the customer. This work presents a method of associating 3D visualizations to discrete event simulations for process simulations. A software system called 3DGen is developed that automates the process of generating a 3D visualization for a discrete event simulation. The 3DGen system is …

Generic Cost Estimation Framework For Design And Manufacturing Evaluation, Uday A. Kilkami

Mechanical & Aerospace Engineering Theses & Dissertations

A major drawback of current cost estimation models is their incapability of embracing effectively complete product development stage. Parametric estimation works well in early stages of design, but in detail design stage, a more complete estimation is provided by process model based and detail estimation techniques. A major paradigm shift is proposed in this work whereby ‘Cost’ is to be considered as a design parameter from scientific perspective, and it is to be treated as a design consequence rather than as an operational outcome. A comprehensive framework using System Analysis fundamentals is designed to study ‘Process Cost’ aspects of part …

Fueling And Fortifying The Foundational Machinery: Religious Necessity And Enlightened Republicanism In America's Founding, Jennifer L. Dyar

History Theses & Dissertations

The debate over the role of religion in the Revolution and Founding of America continues to rage despite years of fruitless wrangling. The obvious influence of Enlightenment thought on these events has led many historians to focus exclusively upon reason's authority, abandoning consideration of religion as a substantive force entirely and concluding it to be incompatible with Enlightenment ideology. Reason and religion, however, were neither incompatible nor mutually exclusive in the Founding. In both their revolutionary struggle for independence and their erection of a governmental framework, the Founders unquestionably utilized Enlightenment rhetoric and reason. This alone, though, was insufficient firs …

External Aerodynamics Of Heavy Ground Vehicles: Computations And Wind Tunnel Testing, Ilhan Bayraktar

Mechanical & Aerospace Engineering Theses & Dissertations

Aerodynamic characteristics of a ground vehicle affect vehicle operation in many ways. Aerodynamic drag, lift and side forces have influence on fuel efficiency, vehicle top speed and acceleration performance. In addition, engine cooling, air conditioning, wind noise, visibility, stability and crosswind sensitivity are some other tasks for vehicle aerodynamics. All of these areas benefit from drag reduction and changing the lift force in favor of the operating conditions. This can be achieved by optimization of external body geometry and flow modification devices. Considering the latter, a thorough understanding of the airflow is a prerequisite.

The present study aims to simulate …

The Development Of An Enterprise Supply Chain Model For Naval Warship Construction, Rex A. Wallen

Computational Modeling & Simulation Engineering Theses & Dissertations

The utilization of computer simulation in the shipbuilding industry is not a new concept and many shipyards in the US and around the world are using simulation tools in a variety of ways with various levels of success. In other industries, computer simulation has proven itself as a powerful tool for reducing non-value added activities and promises to become more prominent in its use as a resource management tool. Its use in the manufacturing of outfitting components in the construction of Naval warships has had limited success due mainly to the inherent nature of ship construction, especially shipyards engaged in …

Beyond The Sea Of Cortes: A Memoir, Rick Skwiot

English Theses & Dissertations

Twenty years ago I was drawn to Mexico by forces that seemed beyond my control. Seduced by the beneficent sun, the warm people, and a palpable, omnipresent magic, I set off not so much to discover the land as to find myself. It was there, among hard-living, licentious Mexicans and expatriates alike, that I came to discover lost inner worlds through the gateway of the senses.

Beyond the Sea of Cortes recounts my early adventures in the town of San Miguel de Allende as well as in Mexico City, Zihuatenejo, Oaxaca, and Guanajuato. It strives to tell the story of …

Robust Face Representation And Recognition Under Low Resolution And Difficult Lighting Conditions, Mohammad Moinul Islam

Electrical & Computer Engineering Theses & Dissertations

This dissertation focuses on different aspects of face image analysis for accurate face recognition under low resolution and poor lighting conditions. A novel resolution enhancement technique is proposed for enhancing a low resolution face image into a high resolution image for better visualization and improved feature extraction, especially in a video surveillance environment. This method performs kernel regression and component feature learning in local neighborhood of the face images. It uses directional Fourier phase feature component to adaptively lean the regression kernel based on local covariance to estimate the high resolution image. For each patch in the neighborhood, four directional …

The Effect Of Model Formulation On The Comparative Performance Of Artificial Neural Networks And Regression, Michael F. Cochrane

Engineering Management & Systems Engineering Theses & Dissertations

Multiple linear regression techniques have been traditionally used to construct predictive statistical models, relating one or more independent variables (inputs) to a dependent variable (output). Artificial neural networks can also be constructed and trained to learn these complex relationships, and have been shown to perform at least as well as linear regression on the same data sets. Research on the use of neural network models as alternatives to multivariate linear regression has focused predominantly on the effects of sample size, noise, and input vector size on the comparative performance of these two modeling techniques. However, research has also shown that …

Vata: An Improved Personal Computer-Based Vowel Articulation Training Aid, Andrew Matthew Zimmer

Electrical & Computer Engineering Theses & Dissertations

This thesis discusses work accomplished on the further development of a vowel articulation training aid for persons with hearing impairments. The system produces visual feedback about the quality of articulation for ten American English monophthong vowel phonemes. A large database of vowel recordings has been collected and used to improve and test the recognition rates of artificial neural networks used by the training aid. A maximum-likelihood classifier has been introduced into the system to improve performance by reducing the likelihood of incorrect feedback produced by the displays. A series of experiments has been performed to examine effects of tuning parameters, …

Meeting The Digital Literacy Needs Of Growing Workforce, Abha Gupta, Hassan Ndahi

Teaching & Learning Faculty Publications

Assessment of computer literacy needs from the perspective of potential workforce development is an important part of an educational program involving adult learners. About 22 percent of adults currently entering the labor market possess the technology skills that are required for 60% of new jobs. This paper describes the training provided to tutors and trainers of adult learning centers in Hampton Roads Virginia. Results showed that the trainees, prior to the training, had limited access to computer technology and needed training in incorporating computer technology in the curriculum. After the training, trainees have shown increased levels of comfort with various …

Model Scheme A Good Fit For C4isr, Andreas Tolk

Computational Modeling & Simulation Engineering Faculty Publications

No abstract provided.

Improved Energy Model For Membrane Electroporation In Biological Cells Subjected To Electrical Pulses, R. P. Joshi, Q. Hu, K. H. Schoenbach, H. P. Hjalmarson

Bioelectrics Publications

A self-consistent model analysis of electroporation in biological cells has been carried out based on an improved energy model. The simple energy model used in the literature is somewhat incorrect and unphysical for a variety of reasons. Our model for the pore formation energy E(r) includes a dependence on pore population and density. It also allows for variable surface tension, incorporates the effects of finite conductivity on the electrostatic correction term, and is dynamic in nature. Self-consistent calculations, based on a coupled scheme involving the Smoluchowski equation and the improved energy model, are presented. It is shown that E(r) becomes …

Electrical Network-Based Time-Dependent Model Of Electrical Breakdown In Water, R. P. Joshi, J. Qian, K. H. Schoenbach

Bioelectrics Publications

A time-dependent, two-dimensional, percolative approach to model dielectric breakdown based on a network of parallel resistor–capacitor elements having random values, has been developed. The breakdown criteria rely on a threshold electric field and on energy dissipation exceeding the heat of vaporization. By carrying out this time-dependent analysis, the development and propagation of streamers and prebreakdown dynamical evolution have been obtained directly. These model simulations also provide the streamer shape, characteristics such as streamer velocity, the prebreakdown delay time, time-dependent current, and relationship between breakdown times, and applied electric fields for a given geometry. The results agree well with experimental data …

Theoretical Predictions Of Electromechanical Deformation Of Cells Subjected To High Voltages For Membrane Electroporation, R. P. Joshi, Q. Hu, K. H. Schoenbach, H. P. Hjalmarson

Bioelectrics Publications

An electromechanical analysis based on thin-shell theory is presented to analyze cell shape changes in response to external electric fields. This approach can be extended to include osmotic-pressure changes. Our calculations demonstrate that at large fields, the spherical cell geometry can be significantly modified, and even ellipsoidal forms would be inappropriate to account for the deformation. Values of the surface forces obtained from our calculations are in very good agreement with the 1–10 mN/m range for membrane rupture reported in the literature. The results, in keeping with reports in the literature, demonstrate that the final shape depends on membrane thickness. …

Using Spreadsheet Programs In Teaching Machine Design, Cheng Y. Lin, Gary R. Crossman

Engineering Technology Faculty Publications

This paper presents an approach on using spreadsheets to teach machine design. It also lists detailed procedures on how to implement the teaching scheme. Results show that spreadsheet programs can help students organize their design procedures. By using the characteristics of spreadsheet programs, students do not have to repeat the same calculation and can get the alternate solution of a design almost instantly when given different values on the inputs. When compared to the method taught by using calculators, students can significantly improve their performance on homework problems and tests. From teaching evaluations, their interest in taking such a course …

Η Photoproduction On The Proton For Photon Energies From 0.75 To 1.95 Gev, M. Bektasoglu, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, S. Stepanyan, J. Yun, Et Al., Clas Collaboration

Physics Faculty Publications

Differential cross sections for γp→ηp have been measured with tagged real photons for incident photon energies from 0.75 to 1.95 GeV. Mesons were identified by missing mass reconstruction using kinematical information for protons scattered in the production process. The data provide the first extensive angular distribution measurements for the process above W = 1.75  GeV. Comparison with preliminary results from a constituent quark model support the suggestion that a third S₁₁ resonance with mass ∼1.8  GeV couples to the ηN channel.