Digital Commons Network^™

Dimensionality Reduction Using Non-Linear Principal Components Analysis, Tara Singh

Electrical & Computer Engineering Theses & Dissertations

Advances in data collection and storage capabilities during the past decades have led to an information overload in most sciences. Traditional statistical methods break down partly because of the increase in the number of observations, but mostly because of the increase in the number of variables associated with each observation. While certain methods can construct predictive models with high accuracy from high-dimensional data, it is still of interest in many applications to reduce the dimension of the original data prior to any modeling of the data. Patterns in the data can be hard to find in data of high dimensionality, …

A Study Of Literacy Efficacy And Student Achievement Among Beginning Middle School Teachers In An Urban Context, Michael J. Mustain

Theses and Dissertations in Urban Services - Urban Education

Many U.S. school districts are addressing concerns in the areas of literacy education, teacher shortages, and overall student achievement. Teacher preparation in the area of literacy education and the ability of core subject teachers to include literacy components in their daily lessons appears vital to student achievement. Teacher shortages, particularly in high need, "hard to staff'' urban schools, are a serious problem that alternative preparation programs help to address. Alternative preparation programs can provide highly qualified teachers in urban schools. The Transition to Teaching (TTT) trained teachers provided literacy education that in turn helped improve benchmark tests, end-of-year tests, cumulative …

Learning As A Nonlinear Line Of Attraction For Pattern Association, Classification And Recognition, Ming-Jung Seow

Electrical & Computer Engineering Theses & Dissertations

Development of a mathematical model for learning a nonlinear line of attraction is presented in this dissertation, in contrast to the conventional recurrent neural network model in which the memory is stored in an attractive fixed point at discrete location in state space. A nonlinear line of attraction is the encapsulation of attractive fixed points scattered in state space as an attractive nonlinear line, describing patterns with similar characteristics as a family of patterns.

It is usually of prime imperative to guarantee the convergence of the dynamics of the recurrent network for associative learning and recall. We propose to alter …

Teacher Factors That Influence Student Achievement: A Study Of Third And Fifth Grade Teachers, Jewelle L. Harmon

Psychology Theses & Dissertations

Student achievement is of the highest concern for the government, educational administrators and parents. Researchers have looked at several possible student factors that affect student achievement. However, very little research has been done on teacher factors and their relationship with student achievement. The current study looked at the relationships among teacher absence, teacher job satisfaction, work-family conflict, family/work conflict, teachers' attitudes towards achievement measures, and their correlation with Virginia's standardized measure of student achievement; the Standards of Learning (SOLs). District differences in student achievement were also examined. Three school districts in southeastern Virginia accepted the invitation to participate. …

Performance Analysis Of Recoverable Flight Control Systems Subject To Neutron-Induced Upsets Using Hybrid Dynamical Models, Hong Zhang

Electrical & Computer Engineering Theses & Dissertations

It has been observed that atmospheric neutrons can produce single-event upsets in digital flight control hardware. Potentially, they can reduce system performance and introduce a safety hazard. One experimental system-level approach investigated to help mitigate the effects of these upsets is NASA Langley's Recoverable Computer System. It employs rollback error recovery using dual-lock-step processors together with new fault tolerant architectures and communication subsystems.

In this dissertation, a class of stochastic hybrid dynamical models, which consists of a jump-linear system and a stochastic finite-state automaton, is used to describe the performance of a Boeing 737 aircraft system in closed-loop with a …

Marine And Freshwater Cyanophages In A Laurentian Great Lake: Evidence From Infectivity Assays And Molecular Analyses Of G20 Genes, Steven W. Wilhelm, Matthew J. Carberry, Melanie L. Eldridge, Leo Poorvin, Matthew A. Saxton, Martina A. Doblin

OES Faculty Publications

While it is well established that viruses play an important role in the structure of marine microbial food webs, few studies have directly addressed their role in large lake systems. As part of an ongoing study of the microbial ecology of Lake Erie, we have examined the distribution and diversity of viruses in this system. One surprising result has been the pervasive distribution of cyanophages that infect the marine cyanobacterial isolate Synechococcus sp. strain WH7803. Viruses that lytically infect this cyanobacterium were identified throughout the western basin of Lake Erie, as well as in locations within the central and eastern …

High Performance Queueing And Scheduling In Support Of Multicasting In Input-Queued Switches, Weiying Zhu

Electrical & Computer Engineering Theses & Dissertations

Due to its mild requirement on the bandwidth of switching fabric and internal memory, the input-queued architecture is a practical solution for today's very high-speed switches. One of the notoriously difficult problems in the design of input-queued switches with very high link rates is the high performance queueing and scheduling of multicast traffic. This dissertation focuses on proposing novel solutions for this problem. The design challenge stems from the nature of multicast traffic, i.e., a multicast packet typically has multiple destinations. On the one hand, this nature makes queueing and scheduling of multicast traffic much more difficult than that of …

Continuously Stratified Flow Dynamics Over A Hollow, David Salas-Monreal

OES Theses and Dissertations

Acoustic Doppler current profiles (ADCP) and density profiles were measured over three lower Chesapeake Bay bathymetric depressions (hollows) in order to determine the effects of a hollow on a continuously stratified flow. Measurements showed an acceleration of the near-bottom flow as it moved toward the deepest part of the hollows, in contrast to the deceleration expected from two-dimensional Bernoulli-type dynamics. The acceleration was attributed to lateral water intrusions that were most apparent during floods. The presence of lateral water intrusions was corroborated by observations in a transverse section that crossed the deepest part of the hollows. The observed deceleration of …

Investigation Of Ultracold Rubidium Atoms In A Pulsed Far Off Resonance Trap, Minarni Minarni

Physics Theses & Dissertations

This dissertation reports on the design, construction, and investigation of a pulsed optical dipole force trap which uses laser light to confine ultracold rubidium (Rb) atoms. Because the laser frequency is detuned far from the atomic resonance frequency, the optical dipole force trap is also called a "far-off-resonance trap" (FORT). The use of pulsed laser light to create an optical trap may find application in expanding the number of atomic species which can be confined. The experiments reported here are principally aimed, however, at understanding the physics of pulsed FORT dynamics in anticipation of using the free electron laser (FEL) …

Biogeochemistry Of Arsenic And Antimony In The North Pacific Ocean, Gregory A. Cutter, Lynda S. Cutter

OES Faculty Publications

The biogeochemical cycles of the metalloid elements arsenic and antimony were examined along a 15,000 km surface water transect and at 9 vertical profile stations in the western North Pacific Ocean as part of the 2002 IOC Contaminant Baseline Survey. Results show that the speciation of dissolved arsenic (As III, As V, and methylated As) was subtly controlled by the arsenate (AsV)/phosphate ratio. An additional fraction of presumed organic arsenic previously reported in coastal waters was also present (~15% of the total As) in oceanic surface waters. Dissolved inorganic antimony displayed mildly scavenged behavior that was confirmed by correlations with …

Characteristics Of Human Figure Drawings Created By Students With Learning Disabilities, Monika L. Isip

EVMS School of Health Professions Theses & Dissertations

Previous research concerning the artistic indicators of learning disabilities has yielded inconsistent results. Children with learning disabilities comprise a heterogeneous population, with diverse strengths and challenges. There has been a lack of research on the graphic indicators of learning disabilities, which takes this diversity into account. This study aimed at exploring the characteristics of Human Figure Drawings (HFDs) created by students with learning disabilities.

The study examined the HFDs of 2 Virginia Beach Public School 2nd graders who were identified by their parents as having learning disabilities; one child’s disability was described as being a decoding deficit and the other …

Substituting Otoliths For Chemical Analyses: Does Sagitta = Lapillus?, Nathan G. Smith, Cynthia M. Jones

OES Faculty Publications

Chemical analysis of fish otoliths has become an important technique in fisheries science with widespread applications. Most research up to this point has focused predominantly on sagittal otoliths, but the underlying assumptions may also apply to lapilli. The goal of this study was to determine whether lapilli and sagittae have the same otolith chemistry and whether one can be substituted for the other for solution-based chemical analysis in wild-captured fish. We compared the stable isotope chemistry (δ13C and δ18O) of paired sagittae and lapilli of juvenile spotted seatrout Cynoscion nebulosus collected from Chesapeake Bay seagrass beds in 2002. …

Virginia Junior Academy Of Science Awards 2006 Awards

Virginia Journal of Science

List of award winners by section for the Virginia Junior Academy of Science 2006 Awards.

New Fellow: Robert A. Willis, Jr.

Virginia Journal of Science

Robert A. Willis, Jr. has been named Fellow of the Virginia Academy of Science. He has been an active member of the Virginia Academy of Science and the Association of Departments of Computer, Information Science/Engineering at Minority Institutions (ADMI) for nearly fifteen years.

On David Roochnik's Beautiful City: The Dialectical Character Of Plato’S Republic, James Ambury

Reconstruction: Studies in Contemporary Culture

[First paragraph]

“Despite appearances to the contrary, especially passages from Book 8, the Republic actually offers a qualified and cautious defense, rather than a resounding condemnation, of democracy. This defense, however, is specifically dialectical” (2). Thus begins David Roochnik’s short but intriguing study of Plato’s Republic, a dialogue long regarded as evidence that Plato was an enemy of democracy. While Socrates adamantly condemns both democracy and the democratic man, Roochnik argues that the Republic as a work is dialectical in character, and only viewed as such can we come to truly grip Plato’s intention when composing it. The Republic, so …

Abstracts Of Papers, 84th Annual Meeting Of The Virginia Academy Of Science

Virginia Journal of Science

Full abstracts of papers for the 84th Annual Meeting of the Virginia Academy of Science, May 25-26, 2006, Virginia Polytechnic Institute and State University, Blacksburg, VA

Whole Word Phonetic Displays For Speech Articulation Training, Fansheng Meng

Electrical & Computer Engineering Theses & Dissertations

The main objective of this dissertation is to investigate and develop speech recognition technologies for speech training for people with hearing impairments. During the course of this work, a computer aided speech training system for articulation speech training was also designed and implemented. The speech training system places emphasis on displays to improve children's pronunciation of isolated Consonant-Vowel-Consonant (CVC) words, with displays at both the phonetic level and whole word level. This dissertation presents two hybrid methods for combining Hidden Markov Models (HMMs) and Neural Networks (NNs) for speech recognition. The first method uses NN outputs as posterior probability estimators …

Balanced Literacy Versus Basal Reading Instruction For Urban African-American, Title I Third-Grade Students, Julie Ann Perkins

Theses and Dissertations in Urban Services - Urban Education

This study compared third-grade reading achievement of urban African-American, Title I students using a basal reading series with those using a balanced literacy program to determine whether the highly structured skills-based methods advocated by The No Child Left Behind (NCLB) Act actually foster or impede reading achievement in an urban school setting.

Two hundred forty-five third-grade African-American, Title I students from an urban elementary school in southeastern Virginia served as subjects for the study. Subjects were studied as intact groups to avoid disruption in the educational setting. Participants in the control group were third-grade classes of urban African-American, Title I …

A Framework For The Representation Of Cohesion In Small Combat Units, William Eugene Warner

Computational Modeling & Simulation Engineering Theses & Dissertations

Current combat simulations deal well with large unit formations, weapon systems, and physical effects such as attrition. Human factors such as morale, cohesion, and effects of stress are modeled much less adequately. Of the human factors affecting the psychology of a combat unit, military psychologists have identified cohesion as one of the most important. The concept of cohesion, referring to both the interpersonal relationships between soldiers in a military unit and to the morale solidarity of a military force, has been central to military analysis for many years.

A model framework has been developed that can operationalize the concept of …

The Analytic Hierarchy & The Analytic Network Processes In Multicriteria Decision Making: A Comparative Study, Ali K. Taslicali

Engineering Management & Systems Engineering Theses & Dissertations

The objective of this investigation is to identify the critical benefits and factors of decision making models in a changing technological environment. Decision making models are helping tools for the managers or decision makers to make future plans by using qualitative or quantitative data. In this research, a general idea about decision making models and, comparison between the two important models, the Analytical Hierarchy Process (AHP) and the Analytical Network Process (ANP), are introduced. The research was done by using the information in the literature and expert judgment. This paper can be used by academics as a foundation for further …

A Markovian Statistical Analysis Of Single-Event Upsets On Closed-Loop Flight Control Systems, Anushka Vishnukumar Lakdawaia

Electrical & Computer Engineering Theses & Dissertations

The operation of aircrafts depend heavily on closed-loop digital flight control systems which can be disrupted or upset by errant neutrons at aircraft flight altitudes. These upsets, called single-event upsets, range from data corruption to short circuits which can potentially cause physical damage to digital devices and unexpected behaviors in flight controls. Experiments conducted at the Los Alamos Neutron Science Center consisted of irradiating an experimental flight control computer (FCC) architecture with a high intensity neutron beam while the FCC controlled a simulation of a Boeing 737. It was postulated that the upset statistics on the FCC could be fitted …

The Reliability Of The Computer Communication Networks Including Mobile Nodes, Sahin Yasar

Electrical & Computer Engineering Theses & Dissertations

The wireless computer networks have an uncertainty in their structures aside from their big advantages for the users. The environmental conditions, changing locations of the mobile hosts and the changing components in the system can easily affect their reliability. In order to know a system capability performing its functions, keep the reliability at a certain level and/or detect the deficiency of the system, it is necessary to analyze the reliability of a computer communication network including the wired and wireless parts. But the above reasons also make the analysis and a unique solution difficult so a set of algorithms is …

Spectral Shape As An Indicator Of Molecular Weight In Chromophoric Dissolved Organic Matter, John Robert Helms

Chemistry & Biochemistry Theses & Dissertations

Spectral slope is a term used to parameterize featureless absorbance spectra according to their shape. Spectral slope is obtained by calculating the slope of the log-linearized absorption spectrum over a given range of wavelengths. Past studies have shown that spectral slope is related to molecular size in fulvic acids. A simple method of spectral analysis that compares spectral slopes obtained from two distinct regions of the UV spectra of aquatic dissolved organic matter is demonstrated. The ratio of these slopes (R_S) shows considerable change during photo-oxidation, variation within estuaries, and substantial shifts with depth in the upper 1000 …

Improving Efficiency In Engineering Design Using Augmented D-Optimal Designs 'Synthetic Jet' Design Optimization Study, Fatih Erdogan

Engineering Management & Systems Engineering Theses & Dissertations

The purpose of this thesis is to study the efficiency of several "design of experiments" (DOE) approaches used for the analysis and optimization of engineering designs. A literature review is conducted to study various "design of experiments" methods and the advantages and limitations of each method are discussed.

As an application, Augmented D-Optimal designs are utilized for a design study of 'synthetic jet'.

With the objective of improving efficiency and providing a minimum point experimental design model, computer-aided D-optimal method is preferred for this study. For setting up the design of the experiments and for performing the analysis of results, …

A Component Based Formal Ontology Model, A Method For Evaluating Such A Model, And The Results Of An Application Of That Method, Charles Tumitsa

Computational Modeling & Simulation Engineering Theses & Dissertations

For systems to truly communicate effectively, more than just data interchange is necessary. The systems must achieve conceptual interoperability, which implies communicating with understanding.

The LCIM (Levels of Conceptual Interoperability Model) describes a number of levels of interoperability, each of which shows systems with an increased amount of conceptual understanding of the other systems they are communicating with. The lowest levels of this model, technical and syntactic interoperability, are achieved (and there are many existing examples) via data exchange in a number of different ways. Research has shown, however, that to attain higher levels of conceptual understanding, that there must …

Process And Product Optimization Techniques - A Comparative Analysis Using Optimization Of Surface Roughness, Amol Suresh Sonje

Mechanical & Aerospace Engineering Theses & Dissertations

Robust design improves the fundamental function of the product or process considering noise factors in DOE. G. Taguchi has made significant advances in the use of experimental design. Taguchi methods are criticized on the basis of failure to deal with interactions, use of SIN ratio and lack of sequential nature of investigation. Response Surface Methodology deals with designing models that represents response in terms of various factors affecting it. Optimization of surface finish is achieved using both Taguchi Methods and Response Surface Methodology.

Dual response approach is a combination of Taguchi methods and RSM techniques in which primary response is …

Computational Aerodynamics Study Of Ahmed Body Car Model, Rajat Trehan

Mechanical & Aerospace Engineering Theses & Dissertations

Vehicle Aerodynamics has been the focus of study by researchers for centuries. This interest can be owed to increasing demand on fuel efficiency, vehicle top speed and acceleration performance. Interior aerodynamics, such as engine cooling, air conditioning, wind noise, stability, and cross wind sensitivity play key role in customer satisfaction. Hence a complete understanding of flow around the vehicle is prerequisite to achieve any of the above parameters. Aerodynamic development of motor vehicle is expensive. Much capital must be invested in test facilities such as wind tunnels and climate tunnels. The models are costly and at the beginning of a …

Investigating The Relationship Between High School Technology Education And Test Scores For Algebra 1 And Geometry, Richard R. Dyer, Philip A. Reed, Robert Q. Berry

STEMPS Faculty Publications

The standards-based reform movement in education that began in the 1980s has evolved. In the 1990s, the focus was on producing subject-area content standards and modifying instruction. Today, the focus has shifted to assessment, and for technology education, demonstrating the impact on children and the efficacy of the discipline within general education. The purpose of this study was to compare the Standards of Learning (SOL) End-of-Course mathematics performance of high school students who completed courses in illustration and design technology to students who have not completed an illustration and design technology course. The following research questions were developed for this …

Thermometric Measurements Of The Molecular Sublayer At The Air-Water Interface, B. Ward

OES Faculty Publications

[1] A series of measurements was conducted in the AirSea Interaction Saltwater Tank (ASIST) to study the response of the air-water interfacial molecular sublayer under various heat flux and wind speed conditions. In-situ gradients were measured with a platinum-plated tungsten wire microthermometer, which resolved the temperature of the thermally conductive sublayer. Air-sea heat flux was controlled by changing the air-water temperature difference (ΔT^AW) and the wind speed, and measurements were made for three ΔT^AW regimes over a range of wind speeds. A function was fitted to the measured temperature profiles as a way of extracting the boundary …

A Comparative Analysis Of Air-To-Ground Engagement Outcomes In The Joint Warfare System (Jwars) And The Jwars-Joint Semi-Automated Forces Federation, Melissa Anne St. Peter

Computational Modeling & Simulation Engineering Theses & Dissertations

Multi-resolution modeling is the process by which a single model is created by connecting multiple individual models to describe phenomena at different levels of resolution [1]. "When we change resolutions, replacing a detailed model by a more aggregate one, we must ask whether results are 'consistent'" [2].

There are many methods of determining if the results of two simulations are 'consistent'. However, they are very entailed and require a detailed understanding of the individual models including their functionality, algorithms, and inner workings. A straight forward and rapid way of assessing potential inconsistencies is through a statistical comparison of the model …