Digital Commons Network^™

Simulator For Concurrent Processing Data Flow Architectures, Mahyar R. Malekpour

Electrical & Computer Engineering Theses & Dissertations

A software simulator capable of simulating execution of an algorithm graph on a given system under the Algorithm To Architecture Mapping Model (ATAMM) rules is presented in this thesis. ATAMM is capable of modeling the execution of large-grained algorithms on distributed data flow architectures. Investigating the behavior and determining the performance of an ATAMM based system requires the aid of software tools. The ATAMM Simulator presented in this thesis is capable of determining the behavior, performance, and reliability of a system without having to build a hardware prototype. Case studies are performed on four algorithms to demonstrate the capabilities of …

Salinity And Secchi Disc Records For Back Bay, Virginia (1925-1989), Mitchell D. Norman, Ronald Southwick

I. Water Quality

All available salinity and water clarity data for Back Bay, Virginia were edited for this manuscript. Quantitative salinity records commence in 1925. These are comprehensive and extend to 1989 except for a major interruption in the 1940's and 1950's. Quantitative water clarity records (Secchi disc visibility) commence in 1959 and are continuous to 1989 with only a few years missing. Since 1925 the water in Back Bay has fluctuated from fresh (less than 0.5 ppt) to brackish (generally oligohaline, 0.5-3.0 ppt). Fresh to slightly brackish (less than 1.0 ppt) conditions existed from the late 1930's to early 1962, from 1975 …

Submerged Aquatic Vegetation Trends Of Back Bay, Virginia, Donald Schwab, Fairfax H. Settle, Otto Halstead, Richard L. Ewell

III. Flora

(First Paragraph): Submerged aquatic vegetation (SAV) is an important part of a healthy Back Bay ecosystem. SAV helps to stabilize sediments that enter the system and to deter shoreline erosion. The submerged macrophytes serve as filters, improving the quality of the water column by removing many pollutants and dissolved nutrients (Clark, et al., 1973; and Stevenson, et al., 1979). These aquatic plants provide important habitats for a variety of wildlife species, which use the grass beds for shelter, feeding and breeding areas. SAV is a major primary producer in the food chain associated within the aquatic and adjoining upland habitats. …

The Rare Plants Of False Cape State Park, Virginia Beach City, Virginia, J. Christopher Ludwig, Joan B. Wright, Nancy E. Van Alstine

III. Flora

In 1990, the Virginia Department of Conservation and Recreation, Division of Natural Heritage, conducted an inventory of rare plants within False Cape State Park. The goal was to provide data for the development of a management strategy to protect the Park's rare plants. There are 37 plants monitored by the Division of Natural Heritage that have been recorded within the Park and 30 were observed during the 1990 inventory, including 18 previously not recorded. Extensive populations of some of these species were observed. This number of rare plants species is higher than in any other area of equal size in …

Water Table Management, Louis E. Cullipher

IV. Management

No abstract provided.

The Currituck Sound Drainage Basin: Perceived Issues And Prospective Management Alternatives, Rebecca R. Rideout, David A. Adams

IV. Management

This paper will summarize the results of a project designed to gather and analyze background information necessary for development of a comprehensive management plan for the Currituck Sound drainage basin, a small portion of the greater Albemarle-Pamlico watershed. In addition to the waters of Currituck Sound, the study area included 26,000 acres of open water in Back Bay, Virginia and the land draining into Currituck Sound, Back Bay, Northwest River, North Landing River, and other tributaries to Currituck Sound (Figure I). Based on North Carolina Center for Geographic Information and Analysis calculations, the Currituck Sound watershed covers approximately 733 square …

Rates Of Sediment Accumulation, Bioturbation And Resuspension In Back Bay, Virginia, A Coastal Lagoon, Donald J.P. Swift, George T.F. Wong

I. Water Quality

Back Bay is the northernmost section of the Albemarle-Pamlico lagoon-estuary system. Back Bay lagoon and its associated barrier (Currituck Spit) are moving landward in response to post-glacial sea level rise (2.6 mm yr^-1). The long term (100 year time scale) landward migration rate of Currituck Spit may be on the order of a meter per year.

Sediment accumulation, resuspension and bioturbation are processes in Back Bay that control the residence time of organic matter in the bay floor. and therefore, effect the rate of nutrient release. As burial proceeds, nutrients in the zone of mixing may be remineralized …

Refuge Management: Committed To The Future, Anthony D. Leger

IV. Management

The Back Bay National Wildlife Refuge was established on June 6, 1938, " ... as a refuge and breeding ground for migratory birds and other wildlife." During its first 30 years, the Refuge was managed similar to other areas of the National Wildlife Refuge System. Dikes were constructed, facilities were built, and wildlife management programs were initiated. In the late 1960's, the emphasis of the area changed, as increasing numbers of beach oriented visitors, primarily using 4 wheel drive vehicles, began using the area. By 1971 public use reached 348,000 visits per year. Throughout the 1970's and early 1980's Refuge …

Electric Field Induced Emission As A Diagnostic Tool For Measurement Of Local Electric Field Strengths, A. N. Dharamsi, K. H. Schoenbach

Bioelectrics Publications

The phenomenon of electric field induced (EFI) emission is examined in several diatomic and polyatomic molecules. The possibility of using this phenomenon as a diagnostic tool to measure, nonintrusively, the strength and direction of local electric fields in plasmas is discussed. An estimate of the EFI signal emitted in a typical application plasma is given. This yields a lower bound on the detector sensitivity necessary to exploit EFI emission in practical applications. It is concluded that, at present, the EFI signal could be measured by some very sensitive infrared detection schemes available. Current progress in infrared detector technology, if maintained, …

Second Coefficient Of Viscosity In Air, Robert L. Ash, Allan J. Zuckerwar, Zhonquan Zheng

Mechanical & Aerospace Engineering Faculty Publications

Acoustic attenuation measurements in air were analyzed in order to estimate the second coefficient of viscosity. Data over a temperature range of 11 C to 50 C and at relative humidities between 6 percent and 91 percent were used. This analysis showed that the second coefficient of viscosity varied between 1900 and 20,000 times larger than the dynamic or first coefficient of viscosity over the temperature and humidity range of the data. In addition, the data showed that the molecular relaxation effects, which are responsible for the magnitude of the second coefficient of viscosity, place severe limits on the use …

The Implementation Of "Lab 2000" And "Synergistic Systems" In Middle School Laboratories In Virginia, Patricia M. Ways

OTS Master's Level Projects & Papers

To solve this problem, the following goals were developed: 1. Determine the effectiveness of the "high tech" laboratories with regard to implementing the middle school curriculum; 2. Make recommendations for facility and curriculum changes based upon the observations of the practicing middle school teachers.

Nonlinear-Interaction Of A Detonation Vorticity Wave, D. G. Lasseigne, T. L. Jackson, M. Y. Hussaini

Mathematics & Statistics Faculty Publications

The interaction of an oblique, overdriven detonation wave with a vorticity disturbance is investigated by a direct two-dimensional numerical simulation using a multidomain, finite-difference solution of the compressible Euler equations. The results are compared to those of linear theory, which predict that the effect of exothermicity on the interaction is relatively small except possibly near a critical angle where linear theory no longer holds. It is found that the steady-state computational results whenever obtained in this study agree with the results of linear theory. However, for cases with incident angle near the critical angle, moderate disturbance amplitudes, and/or sudden transient …

United States Tactical Doctrine, 1855 To 1861: The Mismeasure Of Technology, Marion Vincent Armstrong Jr.

History Theses & Dissertations

This thesis illuminates the state of United States Army tactical doctrine at the beginning of the Civil War. In 1855, the weapons available to the United States Army left much to be desired in terms of firepower. Their limited range and lack of accuracy meant that they could not be relied upon to render the final decision in battle. The tactical system of 1855, however, blended this firepower with the shock action effect of bayonets and sabres, permitting the capabilities of the weaponry to be maximized on the battlefield while at the same time minimizing the deficiencies.

This harmony between …

A Mergeable Double-Ended Priority Queue, S. Olariu, Z. Wen

Computer Science Faculty Publications

An implementation of a double-ended priority queue is discussed. This data structure referred to as min–max–pair heap can be built in linear time; the operations Delete-min, Delete-max and Insert take O(log n) time, while Find-min and Find-max run in O(1) time. In contrast to the min-max heaps, it is shown that two min–max–pair heaps can be merged in sublinear time. More precisely, two min–max–pair heaps of sizes n and k can be merged in time O(log (n/k) * log k).

On A Unique Tree Representation For P4-Extendible Graphs, B. Jamison, S. Olariu

Computer Science Faculty Publications

Several practical applications in computer science and computational linguistics suggest the study of graphs that are unlikely to have more than a few induced paths of length three. These applications have motivated the notion of a cograph, defined by the very strong restriction that no vertex may belong to an induced path of length three. The class of P₄-extendible graphs that we introduce in this paper relaxes this restriction, and in fact properly contains the class of cographs, while still featuring the remarkable property of admitting a unique tree representation. Just as in the case of cographs, the …

Information Technology And Wealth: Cybernetics, History And Economics, Elin Whitney-Smith

Engineering Management & Systems Engineering Theses & Dissertations

Capitalism developed where and when it did because there was high information access. There was high information access because of a major advance in information technology--the press. Where the technology was not controlled by the "powers that be" there was economic growth and a shift in the entire social structure. Where it was controlled there was no structural change and there was economic ruin. The development of capitalism is a major step change in economic growth. It is also a major change in the way people organize themselves into groups.

Major step changes in the growth and in the organization …

Laureate, 1991, Old Dominion University

University Yearbooks

1991 yearbook of Old Dominion University

Effect Of Passive Flow-Control Devices On The Drug Of A Tractor-Trailer Model, Jagjit K. Ahuja

Mechanical & Aerospace Engineering Theses & Dissertations

The aerodynamic drag of tractor trailers is responsible for approximately half of the fuel consumption at highway speeds (55m.p.h.). Thus, it is important that vehicle drag be reduced in order to reduce operating costs and to conserve fuel. The purpose of the subject research conducted in the Old Dominion University Low-Speed Wind Tunnel was to determine the effect of various add-on flow-control devices, such as a cab-mounted flow deflector and gap seals between the tractor and the trailer. In addition, the effect of trailer rear-edge shaping has been studied. This was accomplished by contouring the trailer's rear end. It has …

Continuum Modeling Methodology For Dynamic Behavior Of Towers, Khaled A. Obeid

Civil & Environmental Engineering Theses & Dissertations

A very common problem in Civil Engineering is the analysis and design of lattice structures. These types of structures generally consist of repetitive sections and have been utilized in the erection of transmission and communication towers, space roof trusses, solar energy collectors, and space platforms. Since lattice structures consist of a significantly large number of members and subsequently a large number of nodes, the classical discrete technique of analysis can be very expensive even on today's modern computers. This study applies a rational approach which capitalizes on the repetitive nature of towers to develop the equivalent continuum model for the …

Micromechanics Of Granular Materials And Its Relation To Wave Velocity, Tarun K. Agarwal

Civil & Environmental Engineering Theses & Dissertations

The macro characters of the granular materials depend upon micromechanical parameters such as the void ratio, particle shape, contact force distribution, and initial state of the fabric of the assembly. Since it is difficult to evaluate these internal parameters from laboratory experiments, a macro measure is desired which depends directly on these internal parameters. One such measure has been shown to be dynamic shear modulus but it was incomplete in predicting directional changes in the internal parameters. Therefore, it is hypothesized here that the complete elastic moduli matrix will have more direct information about the internal parameters, especially the dynamic …

Numerical Modeling Of Flame Lift-Off Phenomenon And Calculation Of Thermal Loads On A Methane Fuel Injector With Complex Geometry, Taj O. Mohieldin

Mechanical & Aerospace Engineering Theses & Dissertations

A numerical study has been conducted to analyze a fuel injector with three in-line cylinder geometry that has been adopted as a model for investigating the combustion phenomenon in the 8-Foot High Temperature Tunnel (HTT) combustor at the NASA Langley Research Center. The primary objective here is to analyze the flame lift-off phenomenon in the three cylinder fuel injector geometry in two-dimensions. The fluid mechanics model used in the analysis includes time-averaged Navier-Stokes equations that are employed in conjunction with a two-equation k-$\epsilon$ model for predicting the effects of turbulence. Calculations were performed with three chemistry models, namely fast chemistry, …

Compressed Digital Video Instructional Delivery: A Study Of Student Achievement, Student Attitude, And Instructor Attitude, Eddyth Niceler Worley

Theses and Dissertations in Urban Services - Urban Education

The purpose of this study was to investigate compressed digital video as an instructional delivery system for distance learning. The independent variable was delivery mode. Two levels of this variable were considered. Level 1 was one-way video/two-way audio. Level 2 was two-way video/two-way audio. Student achievement, student attitude, and instructor attitude were measured as dependent variables.

A quasi-experimental study comparing the two delivery modes was conducted. Two treatment groups were established. Both groups received instruction simultaneously from the same instructors. Instructors used both treatment modes (delivery systems) during instruction.

Instructor and student subjects were naval, civilian and military personnel involved …

An Unsolicited Sociotechnical Intervention In A Public System: A Participatory Action Research Approach, Ely Alfred Dorsey Jr.

Engineering Management & Systems Engineering Theses & Dissertations

This research concerns itself with Participatory Action Research in a hostile setting. The thrust is a sociotechnical one, with the intent being to enhance the capacity of the Wallop Public School System, Wallop, USA, to address its problem of racial disparate treatment of Black children. The potential for Organizational Learning among the school system's senior staff is studied. Some new theory about such hostile interventions is proposed. Also discussed are questions about reliability and construct validity within the context of the multiple role playing that an interventionist has in this setting. The role of the press is reflected in the …

Comparison Of Digital Controllers Used In Magnetic Suspension And Balance Systems, William A. Kilgore

Mechanical & Aerospace Engineering Faculty Publications

Dynamic systems that were once controlled by analog circuits are now controlled by digital computers. Presented is a comparison of the digital controllers presently used with magnetic suspension and balance systems. The overall responses of the systems are compared using a computer simulation of the magnetic suspension and balance system and the digital controllers. The comparisons include responses to both simulated force and position inputs. A preferred digital controller is determined from the simulated responses.

Integrated Control Of Thermally Distorted Large Space Antennas, Robert H. Tolson

Mechanical & Aerospace Engineering Theses & Dissertations

Studies on controlling the thermal distortion of large space antennae have generally investigated a single orbital position and have optimized actuator locations based on minimizing the RMS surface deviation from the original parabolic shape. One study showed the benefits of directly using far zone electric field characteristics as the performance measure; but, this approach resulted in a nonlinear programming problem. The objective of the current study is to develop an approach to designing a control system that (1) recognizes the time dependence of the distortion and (2) controls variables that are directly related to far field performance in a quadratic …

Development Of A Perturbation Generator For Vortex Stability Studies, John Edward Riester Jr.

Mechanical & Aerospace Engineering Theses & Dissertations

Theory predicts vortex instability when subjected to certain types of disturbances. It was desired to build a device which could introduce controlled velocity perturbations into a trailing line vortex in order to study the effects on stability. A perturbation generator has been designed and manufactured which can be attached to the center-body of an airfoil type vortex generator. Details of design tests and manufacturing of the perturbation generator are presented. The device produced controlled perturbations with frequencies in excess of 250 Hz. Preliminary testing and evaluation of the perturbation generator performance was conducted in a 4 inch cylindrical pipe. Observations …

A Comparative Analysis Of Pediatric And General Hospital Nurse Recruitment Practices, Rebecca Parsons Scott

Community & Environmental Health Theses & Dissertations

The focus of this study is a comparison of the National Association of Health Care Recruiter's annual recruitment survey with a duplicate survey that was sent to pediatriconly acute care hospitals. The goal was to determine differences between the recruitment and retention statistics found in all hospitals compared to those found in pediatriconly hospitals. Also, a major consideration was to find correlations among the variables in nurse recruitment and retention that might lead to a better understanding of what influences the recruitment budgeting process and how recruitment dollars might be spent most efficiently.

There was no significant difference found between …

The Effectiveness Of Viscoelastic Damping Treatments On A Flexible Manipulator Subjected To Torsional Loads, Leah L. Remias

Mechanical & Aerospace Engineering Theses & Dissertations

The advent of new technology has led to an increasing number of missions in space. The space shuttle Remote Manipulator System (RMS) is a lightweight flexible manipulator currently used in NASA space missions. The future role of the RMS and similar flexible manipulators may include in-space construction and assembly tasks. Because these tasks require precise motion and short settling time of the end-point oscillations, effective vibration control schemes are being investigated.

Passive damping techniques have shown to provide a considerable amount of damping in controlling flexural vibrations. In this research passive damping via constrained viscoelastic damping treatments is explored as …

Dynamics And Control Of Two Suspension Mechanisms For Ground-Based Testing Of Space Structures, Joseph E. Wilson

Mechanical & Aerospace Engineering Theses & Dissertations

Two suspension systems which effectively simulate a gravity-free environment are presented. A single degree-of-freedom suspension system utilizing a specially profiled band mechanism in conjunction with a torsional spring is presented to show its feasibility and applicability for use as a ground-based testing device for flexible space structures. The second device, a two degree-of-freedom suspension system consisting of two springs and a folding linkage is presented to show the feasibility as a testing device for suspending space structures on earth.

Problems resulting in unwanted dynamic behavior due to deviations from the design parameters for both systems are addressed. A nonlinear controller …

From Aristotle To Ibm: Classical Rhetoric And The Teaching Of Technical Writing, Kathleen S. Scharf

English Theses & Dissertations

Over the past two decades, industry has placed increasing demands on higher education to produce students who can quickly adapt to a variety of writing situations. However, due to the relatively recent birth of technical writing as an academic discipline, technical-writing teachers tend to lack solid foundations on which to build their curricula. In their search for theoretical guidance, many teachers are turning to the classical rhetorical theories of Plato and Aristotle. Typically, teachers are applying Aristotle's notions of invention, arrangement, and style to the teaching of technical writing. Unfortunately, their approach tends to truncate Aristotle's five-canon system by deleting …