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Air Force Institute of Technology

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Articles 2521 - 2550 of 3052

Full-Text Articles in Physical Sciences and Mathematics

An Approach To Evaluate Software Effectiveness, Timothy J. Schalick Dec 1996

An Approach To Evaluate Software Effectiveness, Timothy J. Schalick

Theses and Dissertations

The Air Force Operational Test and Evaluation Center (AFOTEC) is tasked with the evaluation of operational effectiveness of new systems for the Air Force. Currently, the software analysis team within AFOTEC has no methodology to directly address the effectiveness of the software portion of these new systems. This research develops a working definition for software effectiveness, then outlines an approach to evaluate software effectiveness-- the Software Effectiveness Traceability Approach (SETA). Effectiveness is defined as the degree to which the software requirements are satisfied and is therefore application-independent. With SETA, requirements satisfaction is measured by the "degree of traceability" throughout the …

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Integrating The Capability Maturity Model For Software And The Quality Air Force Criteria, Marshall B. Messamore Dec 1996

Integrating The Capability Maturity Model For Software And The Quality Air Force Criteria, Marshall B. Messamore

Theses and Dissertations

As defense budgets decrease and it is required to do more with less, the Air Force has chosen to use the Malcolm Baldrige National Quality Award (MBNQA) as the basis for implementing quality principles. The Air Force program is known as Quality Air Force (QAF), and the criteria are referred to as the QAF criteria DEPA95b. At about the same time the Department of the Air Force implemented QAF, the software leaders in the Air Force adopted the Capability Maturity Model for Software (CMM) as the internal standard for Air Force software organizations MOSE9l. Software organizations strapped with both sets …

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A Specific Network Link And Path Likelihood Prediction Tool, Gary K. Moy Dec 1996

A Specific Network Link And Path Likelihood Prediction Tool, Gary K. Moy

Theses and Dissertations

Communications have always been a crucial part of any military operation. As the pace of warfare and the technological complexity of weaponry have increased, so has the need for rapid information to assess battlefield conditions. Message passing across a network of communication nodes allowed commanders to communicate with their forces. It is clear that an accurate prediction of communication usage through a network will provide commanders with useful intelligence of friendly and unfriendly activities. Providing a specific network link and path likelihood prediction tool gives strategic military commanders additional intelligence information and enables them to manage their limited resources more …

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Deconvolution From Wavefront Sensing Using Optimal Wavefront Estimators, Scott R. Maethner Dec 1996

Deconvolution From Wavefront Sensing Using Optimal Wavefront Estimators, Scott R. Maethner

Theses and Dissertations

A cost effective method to improve the space surveillance mission performance of United States Air Force (USAF) ground-based telescopes is investigated and improved. A minimum variance wavefront estimation technique is used to improve Deconvolution from Wavefront Sensing (DWFS), a method to mitigate the effects of atmospheric turbulence on imaging systems that does not require expensive adaptive optics. Both least-squares and minimum variance wavefront phase estimation techniques are investigated, using both Gaussian and Zernike polynomial elementary functions. Imaging simulations and established performance metrics are used to evaluate these wavefront estimation techniques for a one-meter optical telescope. Performance metrics include the average …

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Estimation Of Satellite Orientation From Space Surveillance Imagery Measured With An Adaptive Optics Telescope, Gregory E. Wood Dec 1996

Estimation Of Satellite Orientation From Space Surveillance Imagery Measured With An Adaptive Optics Telescope, Gregory E. Wood

Theses and Dissertations

The use of the matched filter to automatically estimate the pose of a Low Earth Orbiting satellite from imagery taken with an adaptive optics telescope is explored. This work represents the first effort to solve the satellite pose estimation problem while considering the broad range of atmospheric turbulence levels and target visual magnitudes that are encountered in ground based space surveillance operations. Several Algorithms are examined in an effort to determine the performance bounds on the matched filter for this application. Results are given over an extremely wide range of seeing conditions. These results are weighted based on historical data …

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Analysis Of Linkage-Friendly Genetic Algorithms, Laurence D. Merkle Dec 1996

Analysis Of Linkage-Friendly Genetic Algorithms, Laurence D. Merkle

Theses and Dissertations

Evolutionary algorithms (EAs) are stochastic population-based algorithms inspired by the natural processes of selection, mutation, and recombination. EAs are often employed as optimum seeking techniques. A formal framework for EAs is proposed, in which evolutionary operators are viewed as mappings from parameter spaces to spaces of random functions. Formal definitions within this framework capture the distinguishing characteristics of the classes of recombination, mutation, and selection operators. EAs which use strictly invariant selection operators and order invariant representation schemes comprise the class of linkage-friendly genetic algorithms (lfGAs). Fast messy genetic algorithms (fmGAs) are lfGAs which use binary tournament selection (BTS) with …

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Laser-Induced Breakdown Spectroscopy On Solution Samples Using Surface Excitation, Leonard M. Berman Dec 1996

Laser-Induced Breakdown Spectroscopy On Solution Samples Using Surface Excitation, Leonard M. Berman

Theses and Dissertations

Laser-induced breakdown spectroscopy (LIBS) is a spectroscopic technique where output from a pulsed laser is focused onto a target in order to create an intense plasma. The optical emission is characteristic of the elements in the focal volume and can be used for elemental analysis. Research on the detection of nickel in solution in addition to solvent detection of CCl4, CHCl3, C2Cl4, and C2HCl3 has been performed. Breakdown was formed at the sample surface via a Q-switched Nd:YAG laser. Initially, operation of the laser was at 1064 nm/repetition rate of 5 Hz. Experiments …

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Analysis And Design Of Standard Telerobotic Control Software, Matthew L. June Dec 1996

Analysis And Design Of Standard Telerobotic Control Software, Matthew L. June

Theses and Dissertations

The Robotics and Automation Center for Excellence (RACE) has defined an open telerobotics control architecture. This architecture, called the Unified Telerobotic Architecture Project (UTAP), is a proposed standard for all Air Force telerobotic systems. Implementation of UTAP will reduce the cost of robotic applications by increasing software modularity, portability, and reusability. This thesis continued the effort to prove the feasibility of UTAP. In December, 1995, 1st Lt Anchor implemented a portion of the UTAP specification on a PUMA robot. The UTAP-compliant controller exhibited some degradation in the system performance. However, the performance degradation was not fully measured. This thesis extended …

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Unfolding The High Energy Electron Flux From Crres Fluxmeter Measurements, Brian D. Mckellar Dec 1996

Unfolding The High Energy Electron Flux From Crres Fluxmeter Measurements, Brian D. Mckellar

Theses and Dissertations

The Combined Release and Radiation Effects Satellite (CRRES) was launched on 25 July 1990 to collect measurements in the earth's radiation belts. One instrument, the High Energy Electron Fluxmeter (HEEF), measured the flux of electrons in 10 channels with energies between 1 MeV and 10 MeV. The channel sensitivities, Ri(E), have been calibrated and partially re-calibrated. We explore the errors introduced in unfolding the electron flux spectrum from the channel measurements and the propagation and growth of calibration and measurement errors. Using numerical experimentation, we fold the responses with known spectra to obtain simulated measurements, add random measurement and calibration …

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Survivability Analysis Of The Iridium Low Earth Orbit Satellite Network, Douglas K. Stenger Dec 1996

Survivability Analysis Of The Iridium Low Earth Orbit Satellite Network, Douglas K. Stenger

Theses and Dissertations

This thesis evaluates the survivability of the proposed Iridium Low Earth Orbit (LEO) Satellite Network. In addition to the complete Iridium constellation, three degraded Iridium constellations are analyzed. This analysis occurs via the use of simulation models, which are developed to use three dynamic routing algorithms over three loading levels. The Iridium network models use a common set of operating assumptions and system environments. The constellation survivability was determined by comparing packet rejection rates, hop' counts, and average end to end delay performance between the various network scenarios. It was concluded that, based on the established scenarios, the proposed Iridium …

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Simworx: An Ada Distributed Simulation Application Framework Supporting Hla And Dis, Earl C. Pilloud Dec 1996

Simworx: An Ada Distributed Simulation Application Framework Supporting Hla And Dis, Earl C. Pilloud

Theses and Dissertations

This research consisted of the analysis, design, and implementation of a reusable application framework for distributed simulation which is compliant with both the DoD High Level Architecture (HLA) for Modeling and Simulation and the Distributed Interactive Simulation (DIS) standards. The goal was to create an Ada-based system for experimentation in distributed simulation. A subsidiary goal was to integrate the system with an existing Air Force Institute of Technology (AFIT) application framework for virtual simulations, Easy_Sim. The application framework was designed using object oriented techniques to enable experimenters to customize it via inheritance extension. The application framework, named SimWorx, consists of …

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A Software Architecture For Computer Generated Forces In Complex Distributed Virtual Environments, Vincent B. Zurita Dec 1996

A Software Architecture For Computer Generated Forces In Complex Distributed Virtual Environments, Vincent B. Zurita

Theses and Dissertations

Complex Distributed Virtual Environments (DVEs) present an outstanding opportunity for the Department of Defense to train geographically separated units within a single realistic threat environment with minimal logistical considerations or safety concerns. To increase the fidelity of these simulations, minimize cost, and thereby maximize the training potential, DVEs must be populated with a realistic number of Computer Generated Forces (CGFs). These are currently expensive to design and build due to a lack of standard COF architectures. A solution to this problem is presented in the form of a CGF Architecture that is applicable to CGFs that model any weapon system. …

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Mass Transport Of Volatile Organic Compounds Between The Saturated And Vadose Zones, Monte S. Harner Dec 1996

Mass Transport Of Volatile Organic Compounds Between The Saturated And Vadose Zones, Monte S. Harner

Theses and Dissertations

Volatile organic compounds (VOCs) dissolved in the saturated zone are transported into the vadose zone primarily by gaseous phase diffusion. If the saturated zone is remediated, VOCs present in the vadose zone may become a secondary source of contamination for the groundwater. The amount of VOCs that remain in the vadose zone is dependent on site hydrology, soil properties, and the chemical properties of the contaminants. The purpose of this study was to determine what conditions caused VOC concentrations in the vadose zone to significantly recontaminate the saturated zone. A one-dimensional numerical model was developed to investigate the transport of …

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Modeling Marine Exposure To Polychlorinated Biphenyls From Sunken Ships, Charles N. Wendt Dec 1996

Modeling Marine Exposure To Polychlorinated Biphenyls From Sunken Ships, Charles N. Wendt

Theses and Dissertations

In the past, the U.S. Navy has routinely conducted SINKing EXercises (SINKEX) for training, weapon effectiveness tests, and economic disposal of aging assets. Recent concern over polychlorinated biphenyl (PCB) chemicals aboard such target vessels has resulted in a suspension of SINKEX. The U.S. Navy has approximately 200 vessels currently requiring such disposal. Environmental legislation and health concerns preclude selling such vessels to foreign governments or scrapping. This work attempted to model the fate and transport of these PCBs by examining their transport to coastal water and their accumulation in the marine food chain. The model includes biodegradation, upwelling, partitioning of …

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Luminescence Study Of Ion-Implanted Gallium Nitride, Eric Silkowski Nov 1996

Luminescence Study Of Ion-Implanted Gallium Nitride, Eric Silkowski

Theses and Dissertations

Luminescence and absorption measurements were used to demonstrate the efficacy of ion implantation for introducing various classes of dopants into GaN. A wide range of implantation and annealing studies were performed with several dopant species (Ar, Zn, C, O, Si, Be, Mg, Nd, Er). Room temperature ion implantation was performed on MOCVD- and MBE-grown GaN samples at energies between 100 and 1150 keV with doses ranging from 1 x 1013 to 1 x 1015/cm-2. Conventional furnace annealing in flowing NH3 or N2 gas resulted in good implantation damage recovery at an annealing temperature …

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A 2-D Numerical Simulation And Analysis Of A Simple Band Model For The Priz Spatial Light Modulator, Gary D. Barmore Nov 1996

A 2-D Numerical Simulation And Analysis Of A Simple Band Model For The Priz Spatial Light Modulator, Gary D. Barmore

Theses and Dissertations

This dissertation discusses the development of and analyzes the first complete, 2-D numerical simulation of the PRIZ. The simulation is based upon a simple band model of the PRIZ: a single donor, a single trap, and free electron carriers. Modeled mechanisms include photogeneration, energy level transitions, injection, drift currents, diffusion currents, photorefraction and diffraction. The model goes beyond the previous charge and field dynamics of 1-D numerical models to include optical effects, and it eliminates the oversimplifications and assumptions used in earlier mathematical models with closed solutions. Sensitivity analyses and selected simulations provide a better understanding of the dynamic imaging …

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Nlo Waveguide "And" Switch And Method Therefor, John J. Kester, Iyad A. Dajani, Peter M. Ranon, Thomas G. Alley Sep 1996

Nlo Waveguide "And" Switch And Method Therefor, John J. Kester, Iyad A. Dajani, Peter M. Ranon, Thomas G. Alley

AFIT Patents

Method and apparatus are provided for NLO switching by first providing a phase-matched SHG grating which outputs a reinforced SHG beam only when two input beams of frequency (ω) are present in two modes of such wg. The so encoded NLO switch is operated by directing at least two input pulsed laser beams of frequency (ω) into the two modes of the wg to generate a reinforced pulsed output SHG beam and output same from the wg in an NLO switching process. The two input beams desirably have a separate pulse train and the spatial and temporal overlap of the …

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Practical Implementation Of Multiple Model Adaptive Estimation Using Neyman-Pearson Based Hypothesis Testing And Spectral Estimation Tools, Peter D. Hanlon Sep 1996

Practical Implementation Of Multiple Model Adaptive Estimation Using Neyman-Pearson Based Hypothesis Testing And Spectral Estimation Tools, Peter D. Hanlon

Theses and Dissertations

This study investigates and develops various modifications to the Multiple Model Adaptive Estimation (MMAE) algorithm. The standard MMAE uses a bank of Kalman filters, each based on a different model of the system. Each of the filters predict the system response, based on its system model, to a given input and form the residual difference between the prediction and sensor measurements of the system response. Model differences in the input matrix, output matrix, and state transition matrix, which respectively correspond to an actuator failure, sensor failure, and an incorrectly modeled flight condition for a flight control failure application, were investigated …

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Background Graphics: A Decision-Making Hindrance Or Enhancement?, David L. Peeler Jr. Sep 1996

Background Graphics: A Decision-Making Hindrance Or Enhancement?, David L. Peeler Jr.

Theses and Dissertations

This thesis investigated the influence, if any, of background graphics on the decision making process. Specifically the hypotheses tested the affect of background graphics on a decision makers accuracy and confidence. A literature review revealed an abundance of graphic research but little reference to the use of background graphics. Using guidelines previously created for high integrity graphics, a timed 2 x 2 factorial experimental design was developed to compare the responses to both traditional graphics and those treated with background graphics. One hundred forty-seven subjects, all employees of the United States Air Force or defense contractors were involved in the …

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Calibration Of The Checkpoint Model To The Space And Missile Systems Center (Smc) Software Database (Swdb), Karen R. Mertes Sep 1996

Calibration Of The Checkpoint Model To The Space And Missile Systems Center (Smc) Software Database (Swdb), Karen R. Mertes

Theses and Dissertations

This study analyzed the effect of calibration on the performance of the CHECKPOINT Version 2.3.1 software cost estimating model. Data used for input into the model were drawn from the FY 95 USAF SMC Software Database (SWDB) Version 2.1. A comparison was made between the model's accuracy before and after calibration. This was done using records which were not used in calibration, referred to as validation points. A comparison of calibration points, both before and after, was done in order to assess whether calibration results in more consistency within the data set used. Six measures such as magnitude of relative …

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An Exploration Of Environmental Technology Transition From The Laboratory To The Field, Michael A. Greiner Sep 1996

An Exploration Of Environmental Technology Transition From The Laboratory To The Field, Michael A. Greiner

Theses and Dissertations

Environmental policy, social factors, individual behavior, and environmental technologies are key factors in improving the current condition of the environment. The Department of Defense (DoD) is not immune to these aspects, as its actions have and will continue to impact the environment in which they conduct operations. The objective of this research is to analyze the environmental technology aspect of improving environmental conditions. Of particular interest, what barriers and bridges are encountered when an Air Force laboratory transitions environmental technologies to an end-user: operational field organization or major weapon system. The research employs a case study methodology to analyze five …

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Calibration Of The Softcost-R Software Cost Model To The Space And Missile Systems Center (Smc) Software Database (Swdb), Steven V. Southwell Sep 1996

Calibration Of The Softcost-R Software Cost Model To The Space And Missile Systems Center (Smc) Software Database (Swdb), Steven V. Southwell

Theses and Dissertations

The rising number and importance of Department of Defense software developments, when combined with declining defense budgets, has resulted in a critical need to accurately plan and manage software development costs and schedules. Unfortunately, the increasing size, complexity, and diversity of these software developments has made accurate estimating problematic. Uncalibrated software cost models have not generally produced reliable results due to generic default parameters and improper usage. The default parameters cannot hope to accurately represent and predict the wide variability of software efforts to which the models are being applied. However, some of the models have achieved improved accuracy by …

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Development Of A Standard Set Of Indicators And Metrics For Artificial Intelligence (Ai) And Expert System (Es) Software Development Efforts, Derek F. Cossey Sep 1996

Development Of A Standard Set Of Indicators And Metrics For Artificial Intelligence (Ai) And Expert System (Es) Software Development Efforts, Derek F. Cossey

Theses and Dissertations

The purpose of this research was to identify a standard set of indicators and metrics that can be used by program managers to improve their abilities to direct development efforts involving Artificial Intelligence (AI) and Expert Systems (ES). This research addresses two objectives. The first objective is to identify an appropriate set of software indicators and metrics to be used by government program offices for the management of development efforts involving software systems for AI and ES. The second objective is to demonstrate how the resources of the National Software Data and Information Repository (NSDIR) can be used in order …

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The Design Of A Financial Management Database System, Edward G. Leszynski Sep 1996

The Design Of A Financial Management Database System, Edward G. Leszynski

Theses and Dissertations

This research led to the design and development of a financial management database system for the Aeronautical Systems Center (AS C) Environmental Management (EM) Systems Program Office (SPO), which has the responsibility of managing the environmental contracts for the Government-Owned, Contractor-Operated (GOCO) plants that are owned by the Air Force. This thesis investigated the various 'development strategies' and 'methodologies' described in the Management Information Systems literature in order to devise an end-user development strategy capable of meeting the EM SPO's requirements. In addition, the information requirements, conceptual design and prototyping, and procedures phases of the System Development Life Cycle (SDLC) …

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Electrical Characterization Of Gasb Based Semiconductors For 2-4 Micrometers Diode Laser Applications, Daniel K. Johnstone Jun 1996

Electrical Characterization Of Gasb Based Semiconductors For 2-4 Micrometers Diode Laser Applications, Daniel K. Johnstone

Theses and Dissertations

Deep Level Transient Spectroscopy (DLTS) was used to characterize the band offsets and deep levels in MBE grown GaSb-based semiconductors that are used in 2-4 µm laser diode structures. One of several deep level traps found in AlxGa1-xAsySb1-y (x=0, 0.5, 0.6, 1.0) is a GaSb double acceptor trap. Progress is also made in establishing the model for the DX center in this material. The degree of compensation of the donor related DX center by GaSb affect where donors are situated, giving preference to one configuration over the many other possible configurations. One minority …

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Investigation Of Radio Wave Propagation In The Martian Ionosphere Utilizing Hf Sounding Techniques, Robert J. Yowell Jun 1996

Investigation Of Radio Wave Propagation In The Martian Ionosphere Utilizing Hf Sounding Techniques, Robert J. Yowell

Theses and Dissertations

This thesis presents a preliminary design of an ionospheric sounder to be carried aboard one or more of NASA's Mars Surveyor landers. Past Russian and American probes have indicated the existence of an ionosphere, but none of these missions remotely sensed this atmospheric layer from the surface. The rationale for utilizing a surface-based Martian ionospheric sounder is discussed. Based on NASA's choice of launch vehicle and power source, a low-weight, low-powered Chirp sounder using a horizontally-polarized dipole antenna is recommended for the sounder experiment. The sounder experiment should be conducted for at least one Martian year, in order to investigate …

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Characteristic Spatial Quadratures For Discrete Ordinates Neutral Particle Transport On Arbitrary Tetrahedral Meshes, Charles R. Brennan Jun 1996

Characteristic Spatial Quadratures For Discrete Ordinates Neutral Particle Transport On Arbitrary Tetrahedral Meshes, Charles R. Brennan

Theses and Dissertations

Characteristic spatial quadratures for discrete ordinates calculations on meshes of arbitrary tetrahedra are derived and tested, including the step (SC), linear (LC), and exponential (EC) characteristic quadratures and variants that assume constant distributions on cell faces. Tetrahedral meshes accurately model curved surfaces with few cells. A split cell approach subdivides tetrahedra along the streaming direction, reducing the transport to one dimension. Assumed forms of the cell source and entering flux distributions have sufficient parameters to match the zeroth and first spatial moments. These parameters are determined by analytically inverting a linear system (LC), or by numerical inversion using Newton's method …

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Performance Study Of A Brazilian Air Force Data Communications Network, Oswaldo Zanelli Jun 1996

Performance Study Of A Brazilian Air Force Data Communications Network, Oswaldo Zanelli

Theses and Dissertations

This thesis consists of a performance analysis of two network models using different protocols, the X.25 and Asynchronous Transfer Mode (ATM). X.25 is currently used in the data communications network infrastructure in the Brazilian Air Force. ATM is a high speed network technology. Simulations of both models were performed to compare the two technologies. This study examines the traffic load that each network can handle while still providing a good quality of service (QoS). The X.25 network model proved to have a sufficient capacity to handle the projected workload, but it presented a low QoS when a more intense traffic …

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A Methodology For Reengineering Relational Databases To An Object-Oriented Database, Pedro A. Linhares Lima Jun 1996

A Methodology For Reengineering Relational Databases To An Object-Oriented Database, Pedro A. Linhares Lima

Theses and Dissertations

This research proposes and evaluates a methodology for reengineering a relational database to an object-oriented database. We applied this methodology to reengineering the Air Force Institute of Technology Student Information System (AFITSIS) as our test case. With this test case, we could verify the applicability of the proposed methodology, especially because AFITSIS comes from an old version of Oracle RDBMS. We had the opportunity to implement part of the object model using an object-oriented database, and we present some peculiarities encountered during this implementation. The most important result of this research is that it demonstrated that the proposed methodology can …

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Formal Transformations From Graphically-Based Object-Oriented Representations To Theory-Based Specifications, Scott A. Deloach Jun 1996

Formal Transformations From Graphically-Based Object-Oriented Representations To Theory-Based Specifications, Scott A. Deloach

Theses and Dissertations

Formal software specification has long been touted as a way to increase the quality and reliability of software; however, it remains an intricate, manually intensive activity. An alternative to using formal specifications is to use graphically-based, semi-formal specifications such as those used in many object-oriented specification methodologies. While semi-formal specifications are generally easier to develop and understand, they lack the rigor and precision of formal specification techniques. The basic premise of this investigation is that formal software specifications can be constructed using correctness preserving transformations from graphically-based object-oriented representations. In this investigation, object-oriented specifications defined using Rumbaugh's Object Modeling Technique …

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