The History of Princess Anne County Training School and Union Kempsville High School Princess Anne County/Virginia Beach, Virginia 1925-1969

Lucas, Joanne Harris Virginia Polytechnic Institute and State Universit 2013 해외박사(DDOD)

The primary purpose of this study was to investigate the history of Princess Anne County Training School and Union Kempsville High School in Princess Anne County/Virginia Beach, Virginia. The method of inquiry was qualitative, historical research that relied on oral histories to provide a cultural understanding of the school from the perspectives of its students, administrators, teachers, and staff. The school's history was reconstructed through direct engagement with individuals whose interviews recounted the establishment, growth, operation, and demise of Princess Anne County Training School/Union Kempsville High School. In order to minimize the nostalgic influence and bring greater validity to the oral histories, data were also collected from historical accounts, school board and community organization minutes, local periodicals, and school artifacts. Segregation cultivated legally separate-but-equal schools for Blacks and Whites, with little or no attention given to actual equality. In 1925, the Black community in Princess Anne County, Virginia, mobilized to build a high school for their children who were denied an education beyond seventh grade. Princess Anne County Training School opened for Black students in 1938 and initially utilized a curriculum based on industrial education. It was the first and only Black high school in Princess Anne County/Virginia Beach, Virginia. As Princess Anne County Training School progressed, the Black community eventually repudiated the term, training school. The school's name was changed to Union Kempsville High School in the fall of 1961. Gradual desegregation inaugurated by the Brown v. Board of Education decisions led to a decline in student enrollment, and Union Kempsville High School closed in 1969.

The evolution of the non-supplant issue in the federal funding of public education: The policy in Virginia and its national implications

Burnette, Mark A Virginia Polytechnic Institute and State Universit 2005 해외박사(DDOD)

The primary purpose of this study is to assist with the determination of the legality of the policy adopted by the Commonwealth of Virginia of deducting certain federal revenues from the Basic Aid finance formula for public education. First, this study involves a detailed review of the case law pertaining to the non-supplant issue with targeted federal funds. Second, a brief description of the funding models of the time utilized by the states involved in such litigation are provided in order to determine similarities and differences to various state funding systems, including the venerable foundation model utilized by Virginia. The study provides a historical analysis of the legislation involved in the federal support of public education and the introduction of the non-supplant issue into the language of the federal legislation. Historical documents including Constitutional acts and amendments, statutes, and publications of early education scholars are reviewed. In order to understand the subtlety of the non-supplant issue, the structures of the state systems of school finance that have had the issue of non-supplant litigated are described in some detail. The review of law includes cases retrieved from both Westlaw and Lexis Nexis databases and those cases cross-referenced with landmark decisions. It would appear that the policy of deducting certain federal revenues from the Basic Aid entitlements due Virginia localities certainly raises the question of whether the Commonwealth has violated the language of the federal grants. The research in this document will provide comparisons between the case law and the non-supplant issue confronting the Commonwealth. Insight into the legal ramifications of the non-supplant issue and the potential implications that deducting federal revenues from the Basic Aid formula may present will be provided. The consequences for failure to adhere to federal policy regarding the state funding of public education are portrayed in the case law decisions. Further, this research will provide an opinion as to whether the current policy of deducting federal revenues from the Basic Aid formula utilized in Virginia will withstand a legal challenge under the non-supplant language imbedded in federal education grants-in-aid.

A framework for finding and summarizing product defects, and ranking helpful threads from online customer forums through machine learning

Jiao, Jian Virginia Polytechnic Institute and State Universit 2013 해외박사(DDOD)

The Internet has revolutionized the way users share and acquire knowledge. As important and popular Web-based applications, online discussion forums provide interactive platforms for users to exchange information and report problems. With the rapid growth of social networks and an ever increasing number of Internet users, online forums have accumulated a huge amount of valuable user-generated data and have accordingly become a major information source for business intelligence. This study focuses specifically on product defects, which are one of the central concerns of manufacturing companies and service providers, and proposes a machine learning method to automatically detect product defects in the context of online forums. To complement the detection of product defects, we also present a product feature extraction method to summarize defect threads and a thread ranking method to search for troubleshooting solutions. To this end, we collected different data sets to test these methods experimentally. The results of the tests show that our methods are very promising. In fact, in most cases, they outperformed current state-of-the-art methods.

An Institutional Analysis of Differences : The Design of Masters' Programs in Public Affairs

김명환 Virginia Polytechnic Institute and State Universit 2004 해외박사

Early studies in the sociological stream of new institutionalism contributed much to the study of organization, especially in illuminating organizational isomorphism that might appear in organizational fields. Yet, at the same time, they were limited in accounting for organizational differences in the design of institutions. To help explain such differences, this study introduces a conceptual framework that brings together the Selznick tradition of old institutionalism with recent studies in new institutionalism. The framework includes multiple institutional logics, organizational positions, and organizational belief systems, all of which generate particular contexts that convey varying identities and produce organizational variations in institutional design.To examine the utility of the conceptual framework, I applied it to the design of 240 masters’ programs in public affairs that are members of NASPAA, APPAM, or both. I found much variation in the coverage and structure of the programs’ curricula. I discovered, for example, that programs that are affiliated only with NASPAA tend to be located in political science, public administration, and public affairs units; to be ranked in the lower-tier; to have been established in 1970 or later; to have the program mission of producing public leaders; to offer MPAd degrees; and to require higher proportions of core hours to be taken in public management. In contrast, programs affiliated only with APPAM or with both NASPAA and APPAM typically are housed in public policy units, ranked in the upper-tier, were founded in 1969 or earlier, focus on generating policy analysts, offer MPP degrees, and require higher proportions of core hours in public policy. Among the implications of these findings are that public affairs education continues to be polarized into two camps, traditional public administration and public policy. The field still lacks agreement about the courses that should be taken and how they should be taught. It seems that differing interpretations of what public affairs is and how it should be taught have helped generate the variation in the design of masters’ programs in public affairs. The results of the empirical analyses also demonstrate the utility of the conceptual framework for explaining institutional differences (and similarities). More importantly, the concept of identity may offer a helpful way to combine several key features in studying organizations, including micro versus macro approaches, old versus new institutionalisms, and organizational theory versus organizational behavior. Eventually, this idea promises to enrich the analysis of institutional similarities and differences.

The effects of load ratio on threshold fatigue crack growth of aluminum alloys

Newman, John Andrew Virginia Polytechnic Institute and State Universit 2000 해외박사(DDOD)

Most well designed structures initially contain no critical cracks, subcritical cracks can grow to failure under fatigue loading, called fatigue crack growth (FCG). A damage tolerant design philosophy was developed for crack sensitive structures. FCG threshold (ΔK_th) is a value of ΔK (crack-tip loading), below which no significant FCG occurs. Cracks are tolerated if ΔK is less than ΔK_th Many variables influence ΔK_th including microstructure, environment, and load ratio. The current research focuses on load ratio effects on ΔK_th and threshold FCG. Extrinsic load ratio effects operate in the crack wake and include fatigue crack closure mechanisms. Intrinsic load ratio effects operate in the crack-tip process zone and include microcracking and void production. To gain a better understanding of threshold FCG load ratio effects (1) a fatigue crack closure model is developed to consider the most likely closure mechanisms at threshold, simultaneously, and (2 ) intrinsic load ratio mechanisms are identified and modeled. Crack meandering and a limited amount of mixed-mode loading are also considered. The rough crack geometry, approximated as a two-dimensional sawtooth wave, results in a mixed-mode crack-tip stress state. Closure-free load ratio effects were studied for aluminum alloys 2024, 7050, and 8009. Finally, a model is developed to predict the accelerated FCG rates, at higher K_max levels, in terms of crack-tip damage. The effect of humidity (in laboratory air) on threshold FCG was studied to ensure that environmental effects at threshold were separated from load ratio effects. Although changes in humidity were shown to strongly affect threshold FCG rates, this influence was small for ambient humidity levels. Finally, the (extrinsic) fatigue crack closure model and the (intrinsic) crack-tip damage model are put in the context of a comprehensive threshold model. The ultimate goal of the comprehensive threshold model is to predict fatigue lives of cyclically loaded engineering components from (small) crack nucleation, through FCG, and including failure. The models developed in this dissertation provide a basis for a more complete evaluation of threshold FCG and fatigue life prediction. The research described in this dissertation was performed at NASA-Langley Research Center in Hampton, Virginia. Funding was provided through the NASA GSRP program (grant number NGT-1-52174). (Abstract shortened by UMI.).

Deploying an ITS warning system for no-passing zones on two lane rural roads

El Zarif, Jamal A Virginia Polytechnic Institute and State Universit 2001 해외박사(DDOD)

A new safety application, as part of ITS Advanced Rural Transportation System (ARTS), has been developed to be deployed on a two-lane rural road (Route 114), in Southwest Virginia. The route segment under study is subject to significant head-on accidents, as a result of two main conditions: (1) <italic> Illegal passing maneuvers</italic> crossing solid yellow line, and (2) A short passing sight distance due to the <italic>road vertical profile</italic>. Head-on collisions amount nationwide to about 3% of the total number of crashes, mostly due to limited visibility. A limited number of studies have addressed these crashes with the intent of providing ITS safety countermeasures. The majority of these studies dealt with implications of environmental causes (e.g. nighttime and weather conditions) and geometric design causes. The main objective of this research is to design a video detection-based warning system by installing an affordable and efficient system on the vertical crest curve on Route 114, capable of performing the following two main functions: (1) Detect vehicles that attempt to violate the no-passing zone restriction (i.e. when crossing into the opposing direction). (2) Warn the drivers violating the restriction in order to discourage them from continuing their maneuvers. Other objectives, which could be of equal importance, are to: (1) Identify violators through license plate recordings and warn repeat violators by mail. (2) Collect data on vehicle volumes and speeds and drivers' behavior. System architecture as well as detailed system design was developed. Equipment was selected based on detailed specifications for the video camera detection system with the central processor; the warning panel and the enforcement system lower cameras. A system simulation was conducted with the use of a special software program written with MATLAB. The simulation was applied for both “with” and “without” the system cases. The simulation runs showed that the system could virtually eliminate all head-on collisions, should violators obey the early warning messages displayed. Several sensitivity tests were made for different scenarios. The output examined in all these tests showed a high degree of robustness of the system performance, and no single unavoidable crash resulted in all “with the systems” runs. Finally, the viability of the system was evaluated from economic point of view. The financial analysis revealed high economic indicators in terms of benefit-cost ratio BCR (38.9) and modified internal rate of return MIRR (65%) over the 10-year lifetime of the system.

Evaluation of sulfidic materials in Virginia highway corridors

Orndorff, Zenah Wilson Virginia Polytechnic Institute and State Universit 2001 해외박사(DDOD)

Road construction through sulfidic materials in Virginia has resulted in localized acid rock drainage (ARD) that threatens water quality, fill stability, integrity of building materials, and vegetation management. The objectives of this study were: (i) to develop a state-wide sulfide hazard rating map based on characterization of the geologic formations associated with acid roadcuts, (ii) to estimate depth to sulfidic sediments in the Coastal Plain based on landscape relationships, and (iii) to evaluate potential acidity testing procedures on diverse materials. Geologic formations associated with acid roadcuts were characterized by potential peroxide acidity (PPA) and S content, and grouped into four categories. Listed in order of increasing severity, these formations included: the Tabb Formation (Coastal Plain), the Lynchburg Group of the Ashe Formation (Blue Ridge), the Chesapeake Group and Lower Tertiary deposits (Coastal Plain), the Millboro shale, Marcellus shale, Chatanooga shale and Needmore Formation (Valley and Ridge), and the Quantico Formation (Piedmont). Evaluation of landscape parameters near Richmond, Virginia, indicated that the likelihood of encountering sulfidic materials within a given depth at a specific location was related to elevation and mapped soil types. Elevation and soil map units were assigned to risk classes to indicate the likelihood of encountering sulfides within a depth of 9 in. Comparison of PPA and S content for 296 diverse samples indicated that S may serve as a screening tool to evaluate materials without carbonates. Comparison of PPA and conventional Acid-Base Accounting (ABA) for 14 diverse samples indicated that PPA and ABA were highly correlated, with PPA yielding 0.60 to 0.95x the amount of acidity as ABA. Potential acidity by Soxhlet extraction and PPA were equivalent for 3 of 4 diverse samples. Average acidity and metal contents of leachate from Soxhlet extractors were correlated with acidity and metals of road drainage. Sulfide hazard analysis should be an essential step in the pre-design phase of highway construction and other earth-disturbing activities.

Multidimensional linear systems and robust control

Malakorn, Tanit Virginia Polytechnic Institute and State Universit 2003 해외박사(DDOD)

This dissertation contains two parts: Commutative and Noncommutative Multidimensional (<italic>d</italic>-D) Linear Systems Theory. The first part focuses on the development of the interpolation theory to solve the <italic> H</italic><super>∞</super> control problem for <italic>d</italic>-D linear systems. We first review the classical discrete-time 1D linear system in the operator theoretical viewpoint followed by the formulations of the so-called Givone-Roesser and Fornasini-Marchesini models. Application of the <italic> d</italic>-variable <italic>Z</italic>-transform to the system equations yields the transfer function which is a rational function of several complex variables, say <bold>z</bold> = (<italic>z</italic>₁,…,<italic>z_d</italic>). We then consider the output feedback stabilization problem for a plant <italic> P</italic>(<bold>z</bold>). By assuming that <italic>P</italic>(<bold>z</bold>) admits a double coprime factorization, then a set of stabilizing controllers <italic> K</italic>(<bold>z</bold>) can be parametrized by the Youla parameter <italic> Q</italic>(<bold>z</bold>). By doing so, one can convert such a problem to the model matching problem with performance index <italic>F</italic>(<bold> z</bold>), which is affine in <italic>Q</italic>(<bold>z</bold>). Then, with <italic> F</italic>(<bold>z</bold>) as the design parameter rather than <italic>Q</italic>(<bold> z</bold>), one has an interpolation problem for <italic>F</italic>(<bold> z</bold>). Incorporation of a tolerance level on <italic>F</italic>(<bold> z</bold>) then leads to an interpolation problem of multivariable Nevanlinna-Pick type. We also give an operator-theoretic formulation of the model matching problem which lends itself to a solution via the commutant lifting theorem on the polydisk. The second part details a system whose time-axis is described by a free semigroup <math> <f> <sc>F<inf><mit>d</mit></inf></sc></f> </math>. Such a system can be represented by the so-called noncommutative Givone-Roesser, or noncommutative Fornasini-Marchesini models which are analogous to those in the first part. Application of a noncommutative <italic>d</italic>-variable <italic> Z</italic>-transform to the system equations yields the transfer function expressed by a formal power series in noncommuting <italic>d</italic>-indeterminants, say <italic>T</italic>(<italic>z</italic>) = <math> <f> <sum align="r"><ll>v∈<sc>F<inf><mit>d</mit></inf></sc></ll> </sum>T<inf>v</inf>z^v</f> </math> where <italic>z<super>v</super></italic> = <math> <f> z<inf>i<inf>n</inf></inf>&cdots;z<inf>i<inf>1</inf></inf></f> </math> if <italic>v</italic> = <math> <f> g<inf>i<inf>n</inf></inf>&cdots;g<inf>i<inf>1</inf></inf>∈ <sc>F<inf><mit>d</mit></inf></sc></f> </math> and <italic>z_iz_j</italic> ≠ <italic>z_jz_i</italic> unless <italic>i</italic> = <italic>j</italic>. The concepts of reachability, controllability, observability, similarity, and stability are introduced by means of the state-space interpretation. Minimal realization problem is stated and has been solved directly by construction or via the recognizable series in the theory of formal languages.

Multi-dimensional upwind fluctuation splitting scheme with mesh adaption for hypersonic viscous flow

Wood, William Alfred, III Virginia Polytechnic Institute and State Universit 2001 해외박사(DDOD)

A multi-dimensional upwind fluctuation splitting scheme is developed and implemented for two dimensional and axisymmetric formulations of the Navier-Stokes equations on unstructured meshes. Key features of the scheme are the compact stencil, full upwinding, and non-linear discretization which allow for second-order accuracy with enforced positivity. Throughout, the fluctuation splitting scheme is compared to a current state-of-the-art finite volume approach, a second-order, dual mesh upwind flux difference splitting scheme (DMFDSFV), and is shown to produce more accurate results using fewer computer resources for a wide range of test cases. The scalar test cases include advected shear, circular advection, non-linear advection with coalescing shock and expansion fans, and advection-diffusion. For all scalar cases the fluctuation splitting scheme is more accurate, and the primary mechanism for the improved fluctuation splitting performance is shown to be the reduced production of artificial dissipation relative to DMFDSFV. The most significant scalar result is for combined advection-diffusion, where the present fluctuation splitting scheme is able to resolve the physical dissipation from the artificial dissipation on a much coarser mesh than DMFDSFV is able to, allowing order-of-magnitude reductions in solution time. Among the inviscid test cases the converging supersonic streams problem is notable in that the fluctuation splitting scheme exhibits superconvergent third-order spatial accuracy. For the inviscid cases of a supersonic diamond airfoil, supersonic slender cone, and incompressible circular bump the fluctuation splitting drag coefficient errors are typically half the DMFDSFV drag errors. However, for the incompressible inviscid sphere the fluctuation splitting drag error is larger than for DMFDSFV. A Blasius flat plate viscous validation case reveals a more accurate <italic>v</italic>-velocity profile for fluctuation splitting, and the reduced artificial dissipation production is shown relative to DMFDSFV. Remarkably the fluctuation splitting scheme shows grid converged skin friction coefficients with only five points in the boundary layer for this case. A viscous Mach 17.6 (perfect gas) cylinder case demonstrates solution monotonicity and heat transfer capability with the fluctuation splitting scheme. While fluctuation splitting is recommended over DMFDSFV, the difference in performance between the schemes is not so great as to obsolete DMFDSFV. The second half of the dissertation develops a local, compact, anisotropic unstructured mesh adaption scheme in conjunction with the multi-dimensional upwind solver, exhibiting a characteristic alignment behavior for scalar problems. This alignment behavior stands in contrast to the curvature clustering nature of the local, anisotropic unstructured adaption strategy based upon <italic>a posteriori </italic> error estimation that is used for comparison. The characteristic alignment is most pronounced for linear advection, with reduced improvement seen for the more complex non-linear advection and advection-diffusion cases. The adaption strategy is extended to the two-dimensional and axisymmetric Navier-Stokes equations of motion through the concept of fluctuation minimization. The system test case for the adaption strategy is a sting mounted capsule at Mach-10 wind tunnel conditions, considered in both two-dimensional and axisymmetric configurations. For this complex flowfield the adaption results are disappointing since feature alignment does not emerge from the local operations. Aggressive adaption is shown to result in a loss of robustness for the solver, particularly in the bow shock/stagnation point interaction region. Reducing the adaption strength maintains solution robustness but fails to produce significant improvement in the surface heat transfer predictions.

Development of ground penetrating radar signal modeling and implementation for transportation infrastructure assessment

Loulizi, Amara Virginia Polytechnic Institute and State Universit 2001 해외박사(DDOD)

Ground penetrating radar (GPR) technology has been used for the past 20 years for a variety of applications to assess transportation infrastructure. However, the main issue after all these years remains: “How well does GPR work and under what conditions?” Results show that GPR works well for some situations, but is not an appropriate tool for other situations. It is not used currently on a routine basis by the US Departments of Transportation (DOTs) due mainly to difficulties encountered with data interpretation. Data interpretation difficulties are mainly attributed to the fact that images obtained from the reflected signals are not photographs of the features that are beneath the surface being investigated. The images show the amplitude of the radar-reflected signals from the interfaces with different dielectric properties. Therefore, a considerable amount of experience and operator skill may be required to correctly interpret sub-surface radar results. To better understand reflected GPR signals, this research was conducted with the following objectives: to determine the dielectric properties of concrete over the used GPR frequency range; to synthesize the reflected air-coupled radar signals and compare them with measured waveforms; to model and study the effects of simulated defects in concrete on the reflected air-coupled and ground-coupled radar signals; and to validate the research results in the field by predicting layer thicknesses of flexible pavements and detecting moisture in flexible pavement systems. Several concrete slabs, 1.5 x 1.5 m, were constructed with known thicknesses, simulated defects, and different reinforcement configurations. The concrete mixes included four different bridge deck mixes and one concrete pavement mix used in the State of Virginia. Results have shown that the dielectric constant of concrete is frequency and mix dependent. However, modeling the reflected signals using an average complex dielectric constant over the entire radar frequency range led to modeled waveforms comparable to the measured waveforms. Although air- and water-filled voids did distort the reflected waveforms, a model was developed to predict the reflected waveforms from the simulated defects. Reinforcement was found to affect the reflected waveforms only when it was oriented in a direction perpendicular to the GPR antennas. A model was also developed to predict the GPR waveforms obtained from flexible pavements. This model could be used in a procedure to measure layer thicknesses more accurately by including losses that occur inside the pavement materials. Two different case studies, where a ground-coupled GPR system was used to locate moisture at different layers, have led to the conclusion that the ground-coupled GPR is a feasible tool to detect moisture inside pavements.