Digital Commons Network^™

Optimization Of Biomathematical Model Predictions For Cognitive Performance Impairment In Individuals: Accounting For Unknown Traits And Uncertain States In Homeostatic And Circadian Processes, Hans P. A. Van Dongen, Christopher G. Mott, Jen-Kuang Huang, Daniel J. Mollicone, Frederic D. Mckenzie, David F. Dinges

Mechanical & Aerospace Engineering Faculty Publications

Current biomathematical models of fatigue and performance do not accurately predict cognitive performance for individuals with a priori unknown degrees of trait vulnerability to sleep loss, do not predict performance reliably when initial conditions are uncertain, and do not yield statistically valid estimates of prediction accuracy, These limitations diminish their usefulness for predicting the performance of individuals in operational environments. To overcome these 3 limitations, a novel modeling approach was developed, based on the expansion of a statistical technique called Bayesian forecasting. The expanded Bayesian forecasting procedure was implemented in the two-process model of sleep regulation, which has been used …

Microscopic-Macroscopic Simulations Of Rigid-Rod Polymer Hydrodynamics: Heterogeneity And Rheochaos, M. Gregory Forest, Ruhai Zhou, Qi Wang

Mathematics & Statistics Faculty Publications

Rheochaos is a remarkable phenomenon of nematic (rigid-rod) polymers in steady shear, with sustained chaotic fluctuations of the orientational distribution of the rod ensemble. For monodomain dynamics, imposing spatial homogeneity and linear shear, rheochaos is a hallmark prediction of the Doi-Hess theory [M. Doi, J. Polym. Sci. Polym. Phys. Ed., 19 (1981), pp. 229-243; M. Doi and S. F. Edwards, The Theory of Polymer Dynamics, Oxford University Press, London, New York, 1986; S. Hess, Z. Naturforsch., 31 (1976), pp. 1034-1037. The model behavior is robust, captured by second-moment tensor approximations G. Rienäcker, M. Kröger, and S. Hess, Phys. Rev. …

Wealth And Achievement Gaps: An Examination Of Virginia Middle Schools, Paulette Natasha Richmond

Theses and Dissertations in Urban Studies

Achievement gaps, the focus of this research, result from unequal achievement and the variance in achievement existing between different segments of the student population, for example, the difference in achievement between minority students and non-minority students. The No Child Left Behind Act of 2001 and AYP (Adequate Yearly Progress) focus on achievement gaps despite contradictory expressions about the efficacy of the act. The No Child Left Behind Act has created discussion and awareness of race, SES (economically advantaged and disadvantaged) and academic achievement.

There are conflicting beliefs about the impact of resources, funding and wealth on student achievement. This study …

Neighborhood Defined Feature Selection Strategy For Improved Face Recognition In Different Sensor Modalitie, Satyanadh Gundimada

Electrical & Computer Engineering Theses & Dissertations

A novel feature selection strategy for improved face recognition in images with variations due to illumination conditions, facial expressions, and partial occlusions is presented in this dissertation. A hybrid face recognition system that uses feature maps of phase congruency and modular kernel spaces is developed. Phase congruency provides a measure that is independent of the overall magnitude of a signal, making it invariant to variations in image illumination and contrast. A novel modular kernel spaces approach is developed and implemented on the phase congruency feature maps. Smaller sub-regions from a predefined neighborhood within the phase congruency images of the training …

Using Principles Of Momentum Conservation To Develop A Coastal Storm Impulse Scale (Cosi), Chris Adam Klentzman

Civil & Environmental Engineering Theses & Dissertations

Coastal engineers have long recognized the need for a storm classification system that combines wave conditions, storm surge, and the length of time for the storm event. A new classification system has been developed that is based on the conservation of total horizontal momentum. This research concentrated on developing the theory and then applying that theory for a 10-year period of data from the Army Corps of Engineers Field Research Facility (FRF) in Duck, North Carolina. When fully developed, the Coastal Storm Impulse scale (COSI) may be applied to all previous Hurricane and Northeaster storm events along a coast and …

Development Of Fast, Distributed Computational Schemes For Full Body Bio-Models And Their Application To Novel Action Potential Block In Nerves Using Ultra-Short, High Intensity Electric Pulses, Ashutosh Mishra

Electrical & Computer Engineering Theses & Dissertations

An extremely robust and novel scheme for computing three-dimensional, time-dependent potential distributions in full body bio-models is proposed, which, to the best of our knowledge, is the first of its kind. This simulation scheme has been developed to employ distributed computation resources, to achieve a parallelized numerical implementation for enhanced speed and memory capability. The other features of the numerical bio-model included in this dissertation research, are the ability to incorporate multiple electrodes of varying shapes and arbitrary locations. The parallel numerical tool also allows for user defined, current or potential stimuli as the excitation input. Using the available computation …

Freelib: A Self-Sustainable Peer-To-Peer Digital Library Framework For Evolving Communities, Ashraf A. Amrou

Computer Science Theses & Dissertations

The need for efficient solutions to the problem of disseminating and sharing of data is growing. Digital libraries provide an efficient solution for disseminating and sharing large volumes of data to diverse sets of users. They enable the use of structured and well defined metadata to provide quality search services. Most of the digital libraries built so far follow a centralized model. The centralized model is an efficient model; however, it has some inherent problems. It is not suitable when content contribution is highly distributed over a very large number of participants. It also requires an organizational support to provide …

Propulsion Enhancement Contributions To The Performance Of Space Launch Vehicles, Russell H. Edwards

Mechanical & Aerospace Engineering Theses & Dissertations

A research effort has been undertaken to investigate critical aspects of launch vehicle performance as affected by variations in specific launch vehicle parameters. The major portion of the study involves liquid propellant systems. However, since solid propellant systems also play a role in today's launch systems, a representative solid-propellant launch vehicle has also been analyzed. The research undertaken determined that the payload capability of a space launch vehicle, or, conversely, the vehicle total liftoff mass, is highly sensitive to the manner in which the space launch vehicle is staged. The research has led to the development and programming of a …

An Epidemiological Model Of Rift Valley Fever, Holly D. Gaff, David M. Hartley, Nicole P. Leahy

Biological Sciences Faculty Publications

We present and explore a novel mathematical model of the epidemiology of Rift Valley Fever (RVF). RVF is an Old World, mosquito-borne disease affecting both livestock and humans. The model is an ordinary differential equation model for two populations of mosquito species, those that can transmit vertically and those that cannot, and for one livestock population. We analyze the model to find the stability of the disease-free equlibrium and test which model parameters affect this stability most significantly. This model is the basis for future research into the predication of future outbreaks in the Old World and the assessment of …

Multi-Phase Flow Analysis In Oil And Gas Engineering Systems And Its Modelling, Orlando F. Ayala, Luis F. Ayala, Orlando M. Ayala

Engineering Technology Faculty Publications

[Introduction] Two-phase flow is very common in industrial processes and its applications were already in use in ages as remote as the era of Archimedes. At the present time, many industrial processes rely on multi-phase phenomena for the transport of energy and mass or for material processing. During the last century, the nuclear, chemical and petroleum industries propelled intense research activity in the area. Their efforts have been aimed at the demystification of the mechanisms taking place during this complex flow situation.

Part 2: Hidden In Plain Sight: The Ship Repair Industry In Hampton Roads, Regional Studies Institute, Old Dominion University

State of the Region Reports: Hampton Roads

Private-sector shipbuilding and repair is big business in Hampton Roads and accounts, directly and indirectly, for about 15 percent of the total value of the region’s economic activity. More than 160 ship construction and repair firms in the area employ approximately 24,600 people, whose typical compensation is one-third above the regional average.

Is Oyster Shell A Sustainable Estuarine Resource?, Eric N. Powell, John M. Klinck

CCPO Publications

The decline of the eastern oyster (Crassostrea virginica) as an estuarine resource is well documented for many estuaries on the United States east coast. This decline is often associated with a decline in the shell resource and ultimately the disappearance of the shell bed. We develop a model that expressly and conjointly evaluates oyster abundance and surficial shell quantity and examine whether stability in the stock and the habitat can be simultaneously achieved. Simulations suggest that a steady-state shell content exists for any set of recruitment and natural mortality rates and that the amount of shell present at steady state …

Nearshore Surface Temperatures In Antofagasta Bay (Chile) And Adjacent Upwelling Centers, A. Piñones, J. C. Castilla, R. Guiñez, J. L. Largier

CCPO Publications

Several years of sea surface temperature data (1997-2003) for the coast of Antofagasta Bay-a semi-enclosed bay in northern Chile-were analyzed in order to further exploring the nature of a warm-water retention pattern inside the bay. Based on time series techniques, we were able to confirm the persistence of warm water in the bay. This warm feature was found immediately downwind of the upwelling center at Jorgillo Point, where temperatures averaged 2-3 degrees C more than at the exposed upwelling sites outside and the bay. Temporal and spatial patterns in sea surface temperature were determined and showed being well associated with …

Bottom-Up Forcing And The Decline Of Steller Sea Lions (Eumetopias Jubatus) In Alaska: Assessing The Ocean Climate Hypothesis, Andrew W. Trites, Arthur J. Miller, Michael A. Alexander, Steven J. Bograd, John A. Calder, Antonietta Capotondi, Kenneth O. Coyle, Emanuele Di Lorenzo, Bruce P. Finney, Edward J. Gregr, Chester E. Grosch, Thomas C. Royer

CCPO Publications

Declines of Steller sea lion ( Eumetopias jubatus) populations in the Aleutian Islands and Gulf of Alaska could be a consequence of physical oceanographic changes associated with the 1976–77 climate regime shift. Changes in ocean climate are hypothesized to have affected the quantity, quality, and accessibility of prey, which in turn may have affected the rates of birth and death of sea lions. Recent studies of the spatial and temporal variations in the ocean climate system of the North Pacific support this hypothesis. Ocean climate changes appear to have created adaptive opportunities for various species that are preyed upon …

Baroclinic Effects And Tides On The Cape Hatteras Continental Shelf, Dana K. Savidge, Catherine R. Edwards, Mark Santana

CCPO Publications

Seasonal variability has been identified on the shelf near Cape Hatteras in the semidiurnal and diurnal frequency bands. Large summertime semidiurnal currents appear to be an M2 internal tide whose propagation shoreward is supported by strong Middle Atlantic Bight (MAB) seasonal stratification. At the southern limit of the MAB, strong MAB stratification gives way to weaker seasonal stratification in the South Atlantic Bight (SAB), and the M2 internal tide propagates shoreward less effectively. Strong diurnal variability appears in K1 and O1 components in summer, achieving magnitudes as large as the M2. The diurnal components are typically much smaller than M2 …

Assessment Of Skill And Portability In Regional Marine Biogeochemical Models: Role Of Multiple Planktonic Groups, Marjorie A. M. Friedrichs, Jeffery A. Dusenberry, Laurence A. Anderson, Robert A. Armstrong, Fei Chai, James R. Christian, Scott C. Doney, John Dunne, Masahiko Fujii, Jerry D. Wiggert

CCPO Publications

[1] Application of biogeochemical models to the study of marine ecosystems is pervasive, yet objective quantification of these models' performance is rare. Here, 12 lower trophic level models of varying complexity are objectively assessed in two distinct regions (equatorial Pacific and Arabian Sea). Each model was run within an identical one-dimensional physical framework. A consistent variational adjoint implementation assimilating chlorophyll-a, nitrate, export, and primary productivity was applied and the same metrics were used to assess model skill. Experiments were performed in which data were assimilated from each site individually and from both sites simultaneously. A cross-validation experiment was also conducted …

Self-Consistent Analyses For Potential Conduction Block In Nerves By An Ultrashort High-Intensity Electric Pulse, R. P. Joshi, A. Mishra, Q. Hu, K. H. Schoenbach, A. Pakhomov

Bioelectrics Publications

Simulation studies are presented that probe the possibility of using high-field (>100kV ∕ cm), short-duration (∼50ns) electrical pulses for nonthermal and reversible cessation of biological electrical signaling pathways. This would have obvious applications in neurophysiology, clinical research, neuromuscular stimulation therapies, and even nonlethal bioweapons development. The concept is based on the creation of a sufficiently high density of pores on the nerve membrane by an electric pulse. This modulates membrane conductance and presents an effective "electrical short" to an incident voltage wave traveling across a nerve. Net blocking of action potential propagation can then result. A continuum approach based …

The Journey Towards Technological Literacy For All In The United States — Are We There Yet?, Philip A. Reed

STEMPS Faculty Publications

The article discusses technological literacy in the U.S. The author focuses on the history of studying technology within general education and notes the scarcity of technology education requirements in American schools. He examines the impact of various studies conducted by the Standards for Technological Literacy (STL) and the National Research Council (NRC), among others, on technological literacy. The author compares the seventeen processes of researcher Harold Halfin's technological research to the theories outlined in various STL material, including observation, analysis, and visualization.

Review Of The Technology Education Research Conference (Terc), Surfer’S Paradise, Australia, Philip A. Reed

STEMPS Faculty Publications

The following report addresses questions established by the Technical Foundation of America prior to attending the Technology Education Research Conference (TERC) December 7-9, 2006 in Surfer's Paradise, Australia. Responses appear below each of the four questions.

Good Things Come In Small Packages: Tiny Plankton Producing Oxygen Near Dead Zone, Abbie Basile

Libraries Faculty & Staff Publications

(First paragraph) For many, the words “Lake Erie” bring to mind large things: big sport fish, sprawling waterfront homes, and an enormous body of water bordering four states and two countries. Similarly, much of the Lake Erie research of which the public is aware deals with larger biological organisms—larger algae and zooplankton, the small fish that eat the zooplankton, and the large fish that feed on those smaller fish. Over the years, the smaller lake life have been somewhat overlooked.

Istart 2: Improvements For Efficiency And Effectiveness, Irwin B. Levinstein, Chutima Boonthum, Srinivasa P. Pillarisetti, Courtney Bell, Danielle S. Mcnamara

Computer Science Faculty Publications

iSTART (interactive strategy training for active reading and thinking) is a Web-based reading strategy trainer that develops students' ability to self-explain difficult text as a means to improving reading comprehension. Its curriculum consists of modules presented interactively by pedagogical agents: an introduction to the basics of using reading strategies in the context of self-explanation, a demonstration of self-explanation, and a practice module in which the trainee generates self-explanations with feedback on the quality of reading strategies contained in the self-explanations. We discuss the objectives that guided the development of the second version of iSTART toward the goals of increased efficiency …

Assessing The Format Of The Presentation Of Text In Developing A Reading Strategy Assessment Tool (R-Sat), Sara Gilliam, Joseph P. Magliano, Keith K. Millis, Irwin Levinstein, Chutima Boonthum

Computer Science Faculty Publications

We are constructing a new computerized test of reading comprehension called the Reading Strategy Assessment Tool (R-SAT). R-SAT elicits and analyzes verbal protocols that readers generate in response to questions as they read texts. We examined whether the amount of information available to the reader when reading and answering questions influenced the extent to which R-SAT accounts for comprehension. We found that R-SAT was most predictive of comprehension when the readers did not have access to the text as they answered questions.

Providing Vanet Security Through Active Position Detection, Gongjun Yan, Gyanesh Choudhary, Michele C. Weigle, Stephan Olariu

Computer Science Faculty Publications

Our main contribution is a novel approach to enhancing position security in VANET. We achieve local and global position security by using the on-board radar to detect neighboring vehicles and to confirm their announced coordinates. We compute cosine similarity among data collected by radar and neighbors' reports to filter the forged data from the truthful data. Based on filtered data, we create a history of vehicle movement. By checking the history and computing similarity, we can prevent a large number of Sybil attacks and some combinations of Sybil and position-based attacks.

Modeling And Efficient Estimation Of Intra-Family Correlations, Roy Sabo

Mathematics & Statistics Theses & Dissertations

Familial data occur when observations are taken on multiple members of the same family. Due to relationships between these members, both genetic and by cohabitation, their response variables will likely exhibit some form of dependence. Most of the existing literature models this dependence with an equicorrelated structure. This structure is appropriate when the dependencies between family members are similar, such as in genetic studies, but not in cases where we expect the dependencies to differ, such as behavioral comparisons across different age groups. In this dissertation we first discuss an alternative structure based upon first-order autoregressive correlation. Specifically we create …

Testing Methods And Pass/Fail Rates In Developmental Mathematics Classes At Southwest Virginia Community College, Charlotte Tiller

OTS Master's Level Projects & Papers

To solve this problem the following hypothesis was developed: There is no correlation between examination method and pass/fail rate of students in developmental mathematics at Southwest Virginia Community College.

Articulation Trends In Allied Health Programs, Felicia M. Toreno

OTS Master's Level Projects & Papers

The educational environment emphasizes student access to instructional opportunities. Many health programs are located in community colleges or hospitals, and in order to advance educational status, students must be able to transfer credits between multiple educational institutions. Unfortunately, programs are not uniform and many fields of study are guided by strict accreditation regulations. These conflicting requirements often make transfer for students cumbersome. Transfer pathways are often considered by institutions on a program by program basis. This research was designed to analyze the existing pathways present in urban Virginian allied health programs in order to establish trends in articulation. These instructional …

Methodology For Analyzing And Characterizing Error Generation In Presence Of Autocorrelated Demands In Stochastic Inventory Models, Rafael Diaz

Computational Modeling & Simulation Engineering Theses & Dissertations

Most techniques that describe and solve stochastic inventory problems rely upon the assumption of identically and independently distributed (IID) demands. Stochastic inventory formulations that fail to capture serially-correlated components in the demand lead to serious errors. This dissertation provides a robust method that approximates solutions to the stochastic inventory problem where the control review system is continuous, the demand contains autocorrelated components, and the lost sales case is considered. A simulation optimization technique based on simulated annealing (SA), pattern search (PS), and ranking and selection (R&S) is developed and used to generate near-optimal solutions. The proposed method accounts for the …

Termite Resource Partitioning Related To Log Diameter, Deborah A. Waller

Biological Sciences Faculty Publications

The termites Reticuliterines virginicus and R. flavipes are sympatric in forests along the eastern United States from Florida to Maryland. These congeners construct subterranean nests, forage on surface and buried wood, and appear to have very similar ecological requirements. In the present study, I examined host-wood selection by these species in a coastal forest over two years. Logs inhabited by R. virginicus had significantly greater diameters than those used by R. flavipes. It is not known whether this pattern resulted from species-specific differences in preference for host size or competition for preferred logs. Host-wood temperature did not differ for …

Detection Of Mitochondrial Insertions In The Nucleus (Numts) Of Pleistocene And Modern Muskoxen, Sergios-Orestis Kolokotronis, Ross De Macphee, Alex D. Greenwood

Biological Sciences Faculty Publications

Background: Nuclear insertions of mitochondrial sequences (NuMts) have been identified in a wide variety of organisms. Trafficking of genetic material from the mitochondria to the nucleus has occurred frequently during mammalian evolution and can lead to the production of a large pool of sequences with varying degrees of homology to organellar mitochondrial DNA (mtDNA) sequences. This presents both opportunities and challenges for forensics, population genetics, evolutionary genetics, conservation biology and the study of DNA from ancient samples. Here we present a case in which difficulties in ascertaining the organellar mtDNA sequence from modern samples hindered their comparison to ancient DNA …

Technology Education Effects On High School Student's Test Scores, Ross B. Creecy

OTS Master's Level Projects & Papers

The researcher will attempt to answer four specific questions with this study: Do technology education classes have a positive impact on students' SOL scores? On which academic subject's SOL test scores do technology education classes have the greatest impact? On which academic subject's SOL test scores do technology education have the least impact? What can technology education teachers do to increase their positive impact on academic test scores?