Digital Commons Network^™

An Alternative Method For Determining Adjusted Function Points As The Basis For Software Cost Estimating, William Alexander Eldred

Engineering Management & Systems Engineering Theses & Dissertations

As software costs become an increasingly higher percentage of total computer system costs, it becomes increasingly more important for software development managers to have the ability to predict development costs with reasonable accuracy early in the software development cycle. Software development cost estimates are based in large measure on software size. Function points are considered by many to be a de facto industry standard as a size metric. The function points technique, unlike lines-of-code, can be applied early in the software development cycle and is language independent. Critics claim that the function point “value adjustment factor,” which purports to capture …

A Proposed Approach To Iso Compliance And Validation For Metrology Laboratories, J. Lyle Bagley

Engineering Management & Systems Engineering Theses & Dissertations

International competition among metrology laboratories, as well as their customers, has intensified the incentive to seek either accreditation to ISO Guide 25 or ISO 9000 quality system registration for the laboratory. The debate continues as to which is more beneficial to the laboratory and its customers once the decision is made to pursue one or the other. This study addresses the advantages and limitations of each, and how best to prepare for complying with ISO standards. The literature was reviewed and ISO certification experts were questioned about these issues. The results were combined with new applications of existing operations research …

Velocity Estimation Via A Neural Network Enhanced By Classical Detection Algorithms, Zeki Berk Hamşioğlu

Electrical & Computer Engineering Theses & Dissertations

The goal of this research is to show how to solve a velocity estimation problem using a neural network connected to an array of sensors. Motivated by biological studies involving insect vision, the neural network utilized is a member of a class of shunting neural networks. When an object moves across the face of the sensor array, the neural network's pulse response is first temporally located using classical M-ary detection techniques. Both the deterministic and stochastic cases are considered. Then the network's pulse response is post-processed via an existing velocity estimation algorithm based on a Volterra series model of the …

Flexural Behavior Of Thermoplastic Beams With And Without Frp Reinforcement, Hilmi Coskun

Civil & Environmental Engineering Theses & Dissertations

This thesis presents the results of an experimental and theoretical study of the flexural behavior of thermoplastic beams with and without fiber-reinforced plastic (FRP) rebars. Tests are conducted on commercially available thermoplastic beams known as Seatimber. The normal stress-strain relations of both the thermoplastic material and FRP rebars are obtained in tension and compression experimentally. These mechanical property curves are then used as part of the input for developing the theoretical moment-curvature relations using an iterative equilibrium procedure. The moment-curvature relations are in turn used for predicting the beam load-deflection curves via the central finite-difference procedure. Behavior predictions are made …

Minimizing Post-Production Weight Growth In Tanks Using A Decision Analysis Model, Michael F. Cochrane

Engineering Management & Systems Engineering Theses & Dissertations

Post-production weight growth of tanks is an historic problem for the military. Tanks are difficult to transport because of their weight, and post-production modifications tend to cause this weight to increase over the lifecycle of the tank. In this thesis, a computer model is constructed which uses influence diagrams to model tank weight growth as a probabilistic process. Historical weight data for the MI Abrams tank program is used to derive probabilities for the model. The model is used to predict tank weight growth over both the short and long term with the goal of understanding more about how and …

Thermal And Mechanical Behavior Of Cryogenic Propellant Tank Concepts For Advanced Launch Vehicles, H. Kevin Rivers

Mechanical & Aerospace Engineering Theses & Dissertations

An important step in developing a cost-effective, fully-reusable, launch vehicle is the development of durable, lightweight, insulated, cryogenic propellant tanks. Current cryogenic tanks are expendable, and much of the technology that exist is not usable on future vehicles. As part of the Reusable Launch Vehicle/ X-33 Program, an experimental apparatus for evaluating the effects of both thermal and mechanical loading on cryogenic-tank concepts was developed at the NASA Langley Research Center. Studies to determine the behavior of various liquid-oxygen- and liquid-hydrogen-tank concepts under simulated mission conditions were performed as part of this research and are reported. Selected analytical studies of …

Circulation, Vol. 5, No. 1, Center For Coastal Physical Oceanography, Old Dominion University

CCPO Circulation

Fall 1997 issue of CCPO Circulation featuring article "CCPO, ODU, and Internet2"

Formal Specification Of Fragmentation And Reassembly In Ipv6, Ibrahim Sahin

Electrical & Computer Engineering Theses & Dissertations

Development and implementation of a networking standard such as the new Internet Protocol (IPv6) is a very difficult process. Different implementations of the standard must be fully compatible to allow different computers to communicate with each other. However, standards are often ambiguous, frequently a result of providing specifications in the English language. A more formal specification could assist in the design of systems. This thesis demonstrates that capability using the Prototype Verification System (PVS).

In this thesis study, a formal specification for fragmentation and reassembly in IPv6 was created to provide a tool for the standardization of IPv6 using PVS. …

Selective Cvd Growth Of Diamond Crystals On Tungsten, Charles Randal Cole

Electrical & Computer Engineering Theses & Dissertations

Typical field emitters consist of sharp metal tips which usually have a short life due to erosion and contamination. To improve the performance of regular field emitters, diamond can be placed on the emitter tip. This is done by selectively growing diamond on tungsten tips using chemical vapor deposition (CVD) processing. Diamond exhibits negative electron affinity, so that electrons will be emitted by properly biasing the tip.

To obtain single crystal growth right at the tip, a cantilever controlled nucleation method was developed which worked better than other methods. Surface preparation was also important to the growth process. An oxide …

Building Multi-Discipline, Multi-Format Digital Libraries Using Clusters And Buckets, Michael L. Nelson

Computer Science Theses & Dissertations

Our objective was to study the feasibility of extending the Dienst protocol to enable a multi-discipline, multi-format digital library. We implemented two new technologies: cluster functionality and publishing buckets. We have designed a possible implementation of clusters and buckets, and have prototyped some aspects of the resultant digital library.

Currently, digital libraries are segregated by the disciplines they serve ( computer science, aeronautics, etc.), and by the format of their holdings (reports, software, datasets, etc.). NCSTRL+ is a multi-discipline, multi-format digital library (DL) prototype created to explore the feasibility of the design and implementation issues involved with created a …

Thermophilic Bacterial Activity In A Deep-Sea Sediment From The Pacific Ocean, Fred C. Dobbs, Karen A. Selph

OES Faculty Publications

Thermophilic bacterial activity was detected in a deep-sea sediment sample from the South Pacific Ocean at 12 degrees S, 135 degrees W, an area of the seafloor distant from known hydrothermal venting. Incubation of sediments amended with C-14-glutamate indicated maximal respiration (evolution of (CO2)-C-14) and assimilation (incorporation of C-14 into acid-precipitated macromolecules) of substrate at 52 degrees C, relative to 4 and 22 degrees C. A parallel experiment at another site (2 degrees S, 140 degrees W) yielded no evidence of thermophily. Thermophilic bacteria may be deposited in deep-sea sediments following their long-distance dispersal from hydrothermal vents (e.g. the East …

High-Order Finite-Difference Schemes And Their Application To Computational Acoustics, Joe Leo Manthey

Mathematics & Statistics Theses & Dissertations

The primary focus of this study is upon the numerical stability of high-order finite-difference schemes and their application to duct acoustics. Since acoustic waves are known to be non-dissipative and non-dispersive, high-order schemes are favored for their low dissipation and low dispersion relative to the low-order schemes. The primary obstacle to the the development of explicit high-order finite-difference schemes is the construction of boundary closures which simultaneously maintain the formal order of accuracy and the numerical stability of the overall scheme. In this thesis a hybrid seven-point, fourth-order stencil for computing spatial derivatives is presented and the time stability is …

Investigation Of Drag Reduction On A Two-Dimensional Circular Cylinder By Ejecting Jet From The Rear Stagnation Region, Satoshi Atsuchi

Mechanical & Aerospace Engineering Theses & Dissertations

Extensive work in the field of drag reduction has been done in the past. However, this field of study is highly desirable today because of various high-speed research programs. The present study attempts to investigate the feasibility of drag reduction on a cylinder by flow injection from the rear stagnation region. A two-dimensional circular cylinder at Reynolds number l x10⁵with a jet ejected from its tail is selected as a physical model. To tackle this problem, a numerical simulation as well as an experimental approach were used. Despite the recent development of computational fluid dynamics (CFD), computing a …

A Comparison Between Simulated And Measured Free-Flight Vortex Encounter Behavior In The Nasa Langley Full-Scale Wind Tunnel, Robert A. Pfouts

Mechanical & Aerospace Engineering Theses & Dissertations

An examination of the use of static measurements in simulating dynamic aircraft­ wake encounters is presented. By comparing dynamic aircraft-wake vortex encounter measurements obtained in free-flight wind tunnel tests to data obtained from computer­ simulated encounters based on static wind tunnel data, a determination is made concerning the validity of static vortex models in a dynamic flight environment. The development and testing of specialized elements of a flight simulation code are presented and dynamic free-flight measurements and predicted results are compared.

This study shows that static modeling provides reasonable estimates for lateral encounter trajectories when the following aircraft model is …

The Detoxification Of Petroleum Contaminated Coastal Plain Sandy Soil Using An Amended Vermicomposting Approach, John Charles Kraemer

Health Services Research Dissertations

This study explores the feasibility of utilizing an amended vermicomposting treatment approach for detoxifying petroleum hydrocarbon contaminated sandy soil. The bench-scale testing of gasoline and diesel contaminated soil using three test soil vessels and one control soil vessel was performed in a laboratory setting for a six week time period. The control soil received no treatment other than distilled water to maintain soil moisture. Treatment 1 consisted of direct application of liquid municipal biologic sludge on a weekly basis. Treatment 2 consisted of the addition of 30 Eisenia foetida earthworms and distilled water. Treatment 3 consisted of direct application of …

Electromyography (Emg) Signal Classification By Artificial Neural Networks, Behnam Dashtipour

Electrical & Computer Engineering Theses & Dissertations

EMG signal processing is one of the active fields of biomedical signal processing. One unanswered question is how to determine whether a muscle is fatigued by analyzing the EMG signal. Fatigue detection could be useful in several different practical situations. There are several studies which show there are differences between EMG signal features before fatigue and after fatigue. Generally studies are based on an analytical analysis of the EMG signal instead of a quantitative analysis. In all previous studies in EMG signal processing for fatigue/nonfatigue detection, the result is that there exist some differences between the EMG signal before muscle …

Computer-Aided Design Of Coupler-Driven Watt I And Tolerance Synthesis For Four-Bar Linkages, Haitao Li

Mechanical & Aerospace Engineering Theses & Dissertations

Theory to rectify circuit defects in rocker-crank and double-rocker at the synthesis level is described based on the angular joint displacements. It complements the crank-rocker and double-crank circuit rectification to complete the circuit rectification of four-bar linkages. The procedure utilizes the algebraic method where special points followed by a line construction procedure are employed to validate the range of the critical angle that can identify the circuit defects as a function of the design positions prior to the completion of the linkage.

A complete procedure of the rectified synthesis of the coupler-driven Watt I six-bar linkage to pass through the …

Reverse Engineering Of Aircraft Wing Data Using A Partial Differential Equation Surface Model, Jacalyn M. Huband

Mathematics & Statistics Theses & Dissertations

Reverse engineering is a multi-step process used in industry to determine a production representation of an existing physical object. This representation is in the form of mathematical equations that are compatible with computer-aided design and computer-aided manufacturing (CAD/CAM) equipment. The four basic steps to the reverse engineering process are data acquisition, data separation, surface or curve fitting, and CAD/CAM production. The surface fitting step determines the design representation of the object, and thus is critical to the success or failure of the reverse engineering process. Although surface fitting methods described in the literature are used to model a variety of …

Research Related To Multi Degree Of Freedom Magnetic Suspensions, Yan Yang

Mechanical & Aerospace Engineering Theses & Dissertations

This thesis covers the activities associated with 1) recommissioning of the 6-inch Magnetic Suspension and Balance System (MSBS) and 2) enhancing the Annular Suspension and Pointing System (ASPS). These activities continue the program of research in the multi degree of freedom magnetic suspension program at Old Dominion University. The 6-inch MSBS is a large gap magnetic suspension system used as a model support and balance system in wind tunnels. The first stage of recommissioning of the 6- inch MSBS for the 6-inch subsonic wind tunnel is performed. Experimental data and computational results for the magnetic field distribution of the MSBS …

Oral Health Assessment Of Renal Transplant Recipients Undergoing Immunosuppressant Therapy, Coral Diaz

Dental Hygiene Theses & Dissertations

The purpose of this investigation was to assess the oral health, prevalence of intraoral manifestations/infections. and periodontal disease status of renal transplant recipients undergoing immunosuppressive therapy to determine their oral health needs. A purposive sample was selected via the Renal Transplant Center. Sentara Norfolk General Hospital. and Nephrology Associates of Tidewater LTD from which 22 renal transplant recipients who agreed to participate were examined. Three subgroups of the population were studied: individuals with a renal transplant for less than one year. individuals with a renal transplant for one to three years and individuals with a renal transplant for more than …

Circulation, Vol. 4, No. 4, Center For Coastal Physical Oceanography, Old Dominion University

CCPO Circulation

Summer 1997 issue of CCPO Circulation featuring article "HF Radar: Is It Ready for Prime Time"

Resuspension And Transport Of Fine Sediments By Waves, Chiang C. Mei, She-Jun Fan, Kang-Ren Jin

OES Faculty Publications

Although waves are the primary cause of sediment resuspension in the nearshore zone, in existing theoretical models, long-scale currents induced by the mean wind are often taken to be the only agent for the diffusion and convection of resuspended sediments. We present here theoretical examples where waves play a direct role in all aspects of sediment transport. Details are given for the simple case where only waves are present; the wave-induced current and diffusivity are shown to be no less important than similar factors in the wind-driven current. Hence, in a comprehensive model, one should include not only the current …

The Men Behind The Oath: A Profile Of The German Officer Corps In The Interwar Period, 1919-1939, Brian E. Crim

History Theses & Dissertations

The predominance of technocrats within the Reichswehr, the inability of the officer corps to reassert its elite status in the Weimar era, and the extensive interaction between the Reichswehr and a militaristic German society contributed to Hitler's successful absorption of military authority in the 1930s. The social and political upheaval resulting in part from the First World War diffused military authority and diminished the role of the officer corps in German society. The corps struggled to maintain its historic level of corporateness and consistently failed to fulfill its responsibility to the Weimar Republic. The Reichswehr's top officers worked to revitalize …

Groundcrew Coordination Training: An Application Of Team Training To Aviation Ramp Activities, I. Benjamin Sian

Psychology Theses & Dissertations

Crew Resource Management (CRM) training has been used effectively in civilian and military aviation to improve flight safety and reduce mishaps. Aircrew Coordination Training (ACT), the Navy's version of CRM, has had similar effects. An examination of aviation ground mishaps by the Naval Safety Center revealed that the same team coordination breakdowns affecting aircrews were impacting groundcrews. In order to explore the viability of team training for aviation ground personnel, two studies were conducted to test the generalizability of the existing ACT program in a maintenance context. Specifically, "Groundcrew Coordination" Training (GCT) was tailored for training flight line personnel who …

A Piezoresistive Metal Thin Film Tilt Sensor, Todd Allan Lindley

Electrical & Computer Engineering Theses & Dissertations

Thin film strain gauges have many applications as transducers for monitoring pressure, vibration, and acceleration. In this thesis, a simple system, consisting of a Nichrome thin film strain gauge deposited on a glass substrate, is investigated in detail. Finite element analysis is used to model the expected sensor behavior. The substrate is shaped to exhibit a constant strain distribution, and is set up in a cantilever beam configuration. R. F. sputtering is used to deposit the Nichrome film, and the resistor pattern is transferred via photolithography. The gravitational force on a mass attached to the free end of the sensor …

Specification And Verification Of Generic Cell Rate Algorithms In Pvs, Huseyin Ozgungor

Electrical & Computer Engineering Theses & Dissertations

Formal verification methods have been considered as a powerful complementary approach to define standards and to prove correctness of the systems. In this work, formal specification of Generic Cell Rate Algorithms are defined and proved. The specification process enables standardization for constructing Generic Cell Rate Algorithms. Standardization is an important process in the Asynchronous Transfer Mode (ATM) networks. By employing formal methods, the necessary standards could be constructed to allow different algorithms to be employed which still meet system requirements. Those system requirements are quantified in the Quality of Service (QOS).

Congestion management is a vital concept for networks in …

Interactive Approach For Geometry Definition With Automatically Differentiated Sensitivities For Practical Airplane Design, Yvette Cordero

Mechanical & Aerospace Engineering Theses & Dissertations

First, a newly developed interactive surface generation tool is described for the conceptual design phase and aerodynamic shape optimization of aircraft. The new design tool is called Interactive Rapid Airplane Parametric Input Design (IRAPID) for fuselage and wing body configurations, and Blended Wing Body (BWB) generator for flying wing configurations. The development of the software is based on the RAPID methodology, which incorporates a partial differential equation approach to surface design. By incorporating physical airplane design parameters into the boundaty conditions of the partial differential equation, the solution surface of a wing configuration is generated. The construction of fuselage components …

Dyna3d Simulations Of Low-Speed Impact Response Of Laminated Composite Panels, Kenneth William Barlow

Mechanical & Aerospace Engineering Theses & Dissertations

Low-speed impact response of laminated composite panels is simulated without material damage using the DYNA3D finite element analysis code. The DYNA3D code is a nonlinear transient dynamics simulation tool with a contact algorithm for impact. By gaining a more comprehensive understanding of this dynamic impact event, this work is meant to contribute to improving designs for damage tolerance and residual strength by providing modeling and analysis guidelines for the analyst.

Structural modeling of the laminate and the impact event are found to be important factors for the analyst to consider. Since DYNA3D uses an explicit formulation, problem size is constrained …

Development Of A Photon Counting System For Ozone Differential Absorption Lidar Signal Detection, Bradley Allen Eccles

Electrical & Computer Engineering Theses & Dissertations

A photon counting system was assembled and integrated into an existing ozone differential absorption lidar signal detection system to improve the range of ozone measurement. Results of data extraction from decaying ozone return signals are presented. Photomultiplier tube detector models EMI 9214Q and EMI 9B17Q are evaluated and characterized. Detector operating performance was based on tube quantum efficiency, gain, dark current, and linearity. The influence of photomultiplier tube characteristics on photon counting performance are discussed along with the recommended optimum photon counting operating conditions. Two photomultiplier gating schemes, focus grid and four dynode gating, are described for use in photon …

The Relationship Between Job Satisfaction And Collegial Support To Retention Of Nurse Educators In Baccalaureate And Higher Degree Nursing Programs In Virginia, Estella Mary Henry Reynolds

Theses and Dissertations in Urban Services - Urban Education

This descriptive correlational study was designed to explore job satisfaction and collegial support in relation to the retention of nurse educators.

A survey questionnaire adapted from Batiste-Beaty (1990/1991) was used to collect data on nurse educators' retention rates and their perceptions of job satisfaction and collegial support in their present institutions. The survey was distributed to the 350 faculty members in the 12 baccalaureate and higher degree nursing programs in the Commonwealth of Virginia. The survey had a 51% return rate, with a total of 178 respondents. The two primary statistical procedures used in analyzing the data were Pearson's product-moment …