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Theses and Dissertations

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An Application Of The Object-Oriented Paradigm To A Flight Simulator, Dennis J. Simpson Dec 1991

An Application Of The Object-Oriented Paradigm To A Flight Simulator, Dennis J. Simpson

Theses and Dissertations

This thesis describes the object-oriented software development techniques that were used to analyze, design and implement a flight simulator. The objective of this thesis was to present a comprehensive object-oriented software development methodology and show how it was used in constructing an actual application. An extensive review of current object-oriented practices is presented along with the methods that were used to take the flight simulator from analysis to design and through to implementation. The description of the methodology concentrates upon the design and implementation phases of the object-oriented software lifecycle. Examples from the design of the flight simulator demonstrate how …

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A Hybrid Approach To Battlefield Parallel Discrete Event Simulation, Steven R. Soderholm Dec 1991

A Hybrid Approach To Battlefield Parallel Discrete Event Simulation, Steven R. Soderholm

Theses and Dissertations

This thesis describes a method of parallelizing a battlefield discrete event simulation. The method combines elements of conservative time synchronization together with elements of optimistic computation and local rollback on a message passing hardware architecture. The battle simulation features aircraft moving in a battle area and launching missiles at enemy aircraft. Aircraft are randomly grouped into logical process (LPs), and a single LP is assigned to each processor. Aircraft state information is replicated across all LPs. Only the LP with the minimum next event time can execute safely. While one LP is executing safely all other LPs are precomputing their …

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A Cache Design To Exploit Structural Locality, Curtis M. Winstead Dec 1991

A Cache Design To Exploit Structural Locality, Curtis M. Winstead

Theses and Dissertations

A design and VHDL implementation of a content-addressable memory (CAM) to exploit structural locality is the subject of this research. The concept of structural locality is that memory locations are referenced in the same order as they were previously referenced. Therefore, if memory locations that exhibit structural locality can be made available to the CPU (Center Processing Unit) through a fast data store, an increase in speed of the computer system can be realized. The CAM's purpose is to store memory references in the order they were used by the CPU and prefetch these locations to a smaller on- chip …

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Parallelizing Serial Code For A Distributed Processing Environment With An Application To High Frequency Electromagnetic Scattering, Paul R. Work Dec 1991

Parallelizing Serial Code For A Distributed Processing Environment With An Application To High Frequency Electromagnetic Scattering, Paul R. Work

Theses and Dissertations

This thesis investigates the parallelization of existing serial programs in computational electromagnetics for use in a parallel environment. Existing Algorithms for calculating the radar cross section of a object are covered, and a ray-tracing code is chosen for implementation on a parallel machine. Current parallel architectures are introduced and a suitable parallel machine is selected for the implementation of the chosen ray tracing algorithm. The standard techniques for the parallelization of serial code are discussed, including load balancing and decomposition considerations, and appropriate methods for the parallelization effort are selected. A load balancing algorithm is modified to increase the efficiency …

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Formalization And Validation Of An Sadt Specification Through Executable Simulation In Vhdl, Daniel L. Eickmeier Dec 1991

Formalization And Validation Of An Sadt Specification Through Executable Simulation In Vhdl, Daniel L. Eickmeier

Theses and Dissertations

Formalizing an informal requirements specification, such as SADT, and executing the formal specification in a simulation environment, such as VHDL, provides a requirements analyst a means to validate the behavior of a specification early in the development life cycle. This research effort investigated and demonstrated the feasibility and benefit of transforming an SADT specification of a system into an equivalent VHDL executable simulation. Both non-time related behavior and concurrent, real-time related behavior is addressed. First, a decision table extension to SADT is created so that detailed, executable behavior can be specified. Next a mapping from SADT to VHDL is defined. …

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Proportional Plus Integral Control Of Aircraft For Automated Maneuvering Formation Flight, John L. Dargan Dec 1991

Proportional Plus Integral Control Of Aircraft For Automated Maneuvering Formation Flight, John L. Dargan

Theses and Dissertations

In this study an automated formation control system for a lead and wing aircraft flight is developed. The proposed formation control system is capable of controlling like or dissimilar aircraft in maneuvering formation flight. Thus, two versions of the C-130 aircraft, the C-130A and the C-130B, are modelled. The C-130B has superior performance characteristics to that of the C- 130A. The wing aircraft continuously measures lead aircraft position with an ideal on-board relative position sensor, maneuvering to maintain relative position. External formation guidance is assumed to be released in a single data burst, consisting of formation geometry and nominal separation …

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Simulation Of Finite-Precision Effects In Digital Filters, Perry L. Choate Dec 1991

Simulation Of Finite-Precision Effects In Digital Filters, Perry L. Choate

Theses and Dissertations

This thesis develops and demonstrates software that models finite- precision effects in digital filters. Coefficient quantization and internally generated roundoff noise effects are simulated by rounding coefficients and multiplier output values to (B+1) bits. Outputs include magnitude and phase responses that may be plotted to show results of coefficient quantization. The output noise power due to roundoff is calculated. Three types of digital filter structures are examined. The first type is direct form I implementation for FIR and IIR structures, second is direct form II, and third is cascading the canonic direct form II second-order sections for higher order filter …

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Comparison Of Afitpac Versus Nos And A Packet Radio Network Design, Thomas A. Iannelli Dec 1991

Comparison Of Afitpac Versus Nos And A Packet Radio Network Design, Thomas A. Iannelli

Theses and Dissertations

This thesis encompasses two themes: (1) A comparison of the Network Operating System (NOS) software package, developed by Phil Karn and others, and AFITPAC, written by Marsh and Geier at the Air Force Institute of Technology. The comparison is based on the Air Force Logistics Command's requirements for the development of a Packet Radio Network program. The results of the comparison are a recommendation that use of the NOS package be pursued because it can meet all twelve of the requirements and compiles with five of the Military Standard Protocols. (2) The design of a personal computer Packet Radio Network …

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An Investigation Of A Design For A Finite-Difference Time Domain (Fdtd) Hardware Accelerator, James R. Marek Dec 1991

An Investigation Of A Design For A Finite-Difference Time Domain (Fdtd) Hardware Accelerator, James R. Marek

Theses and Dissertations

This study investigated increasing the speed of Finite-Difference Time Domain (FDTD) cell calculations through a special purpose architecture using Very Large Scale Integration (VLSI). These FDTD cell equations model inhomogeneous, isotropic, lossy magnetic and dielectric materials. Special attention was given to simplicity and performance, using the fastest components generally available in AFIT VLSI programs, while attempting to minimize component count. A VHSIC Hardware Description Language simulation of the proposed chip established design feasibility and provided performance estimates: 350 ns to generate the first cell value, 200 ns thereafter (30 MFLOPS maximum double-precision). This study also implemented boundary conditions in hardware …

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Sensing Refractive Turbulence Profiles Using Wave Front Slope Measurements From Two Reference Sources, Michael D. Rejack Dec 1991

Sensing Refractive Turbulence Profiles Using Wave Front Slope Measurements From Two Reference Sources, Michael D. Rejack

Theses and Dissertations

This thesis examines a remote sensing technique for measuring the atmospheric structure constant as a function of altitude by performing spatial correlation or wavefront sensor measurements. Two point sources are used to irradiate two wavefront sensors in the aperture plane of an optical system. The geometric relationship between the sources and the sensors gives rise to crossed optical paths. At the point where the paths cross, the correlation value of the turbulence contributions will be at a peak. The correlation is shown to be mathematically related to the structure constant in terms of an integral of the structure constant multiplied …

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Principal Base Parameter Analysis: Implementation And Analysis In An Adaptive Model-Based Robotic Controller, Gregory L. Showman Dec 1991

Principal Base Parameter Analysis: Implementation And Analysis In An Adaptive Model-Based Robotic Controller, Gregory L. Showman

Theses and Dissertations

Principal Base Parameter Analysis (PBPA) is a general and systematic procedure for determining the dynamic parameters that directly contribute to the joint torques of a manipulator, ranked in order of sensitivity. The feasibility of employing PBPA as an aid in the design and tuning of adaptive model-based controllers for industrial manipulators is rigorously investigated. This is accomplished by employing PBPA to determine the minimal size of the adaptive parameter vector and more importantly, to develop a less heuristic procedure for controller tuning. A simple, step-by-step procedure is developed wherein the manipulator torque equations are used in conjunction with PBPA to …

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Image Analysis Using Gabor Transforms: Correlated With Human Saccadic Movement Data To Identify The Human Visual Search Strategy, Ralph J. St John Dec 1991

Image Analysis Using Gabor Transforms: Correlated With Human Saccadic Movement Data To Identify The Human Visual Search Strategy, Ralph J. St John

Theses and Dissertations

This thesis investigated whether a relationship exists between the Gabor Correlation Coefficient (GCC) magnitudes of fixation points for a set of images viewed by six subjects and the human visual search strategy. A couple of different relationships were investigated. First, the data were analyzed to determine if the GCC magnitudes of human fixation points predicted the time ordered sequence of human fixation points during the performance of a visual search. Second, the data were analyzed to determine if there was a significant difference between the GCC magnitudes of the human fixation points and the GCC magnitudes of a random set …

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Face Recognition With The Karhunen-Loeve Transform, Pedro F. Suarez Dec 1991

Face Recognition With The Karhunen-Loeve Transform, Pedro F. Suarez

Theses and Dissertations

The major goal of this research was to investigate machine recognition of faces. The approach taken to achieve this goal was to investigate the use of Karhunen-Loe've Transform (KLT) by implementing flexible and practical code. The KLT utilizes the eigenvectors of the covariance matrix as a basis set. Faces were projected onto the eigenvectors, called eigenfaces, and the resulting projection coefficients were used as features. Face recognition accuracies for the KLT coefficients were superior to Fourier based techniques. Additionally, this thesis demonstrated the image compression and reconstruction capabilities of the KLT. This theses also developed the use of the KLT …

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Self-Pumped Phase-Conjugate Twyman-Green Interferometry Using A Batio3 Crystal, Deborah A. Determan Dec 1991

Self-Pumped Phase-Conjugate Twyman-Green Interferometry Using A Batio3 Crystal, Deborah A. Determan

Theses and Dissertations

The Air Force uses optical imaging systems in many fields such as communications, target recognition, and missile guidance. For proper execution of these applications, the optical imaging systems use in these fields must be of extremely high quality so that an ideal image is obtained. In divergent beam configurations, this type of interferometer would eliminate the need for high quality reference optics needed in conventional Twyman-Green interferometry. The objective of this thesis is to demonstrate phase conjugate Twyman-Green interferometry using a barium titanate (BaTiO3) crystal as the phase conjugating mirror in the reference arm of the interferometer and …

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Photoluminescence Spectroscopy Of Mbe Grown Gallium Antimonide, John A. Dorian Dec 1991

Photoluminescence Spectroscopy Of Mbe Grown Gallium Antimonide, John A. Dorian

Theses and Dissertations

Experimental data are presented for the energy levels of the native acceptor and bound exciton emissions of GaSb grown by MBE and studied with low temperature photoluminescence (PL) spectroscopy. The undoped GaSb emissions showed a donor-acceptor pair transition with an observed emission peak at 776 meV, a peak at 716 meV usually associated with the ionization level of the acceptor, and bound exciton transitions in the energy range from 796 to 804 meV. Other unidentified peaks were observed at about 805 meV. Temperature and power dependence studies of the acceptor peak confirmed donor-acceptor pair (DAP) behavior. A GaSb sample grown …

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A Topographical Analysis Of The Human Electroencephalogram For Patterns In The Development Of Motion Sickness, George S. Vogen Dec 1991

A Topographical Analysis Of The Human Electroencephalogram For Patterns In The Development Of Motion Sickness, George S. Vogen

Theses and Dissertations

A topographical analysis was performed on 12 electroencephalograms (EEGs) collected from 10 volunteers who experienced motion sickness through cross-coupled Coriolis stimulation. Seven males and three females participated in the research conducted at the Air Force Institute of Technology, Wright- Patterson AFB. Two male volunteers participated in double-blind placebo/ phenytoin trials. Static brain maps and dynamic EEGs which focused on delta (below 3Hz) activity during the development of motion sickness revealed a seizure-like propagation pattern. With initial symptoms, a clear left parietal focus was seen in all records. A less dominant left fronto-temporal focus was present in 11 of the 12 …

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Improving Stochastic Communication Network Performance: Reliability Vs. Throughput, Leonard J. Jansen Dec 1991

Improving Stochastic Communication Network Performance: Reliability Vs. Throughput, Leonard J. Jansen

Theses and Dissertations

This research investigated the measurement and improvement of two performance parameters, expected flow and reliability, for stochastic communication networks. There were three objectives of this research. The first was to measure the reliability of large stochastic networks. This was accomplished through an investigation into the current methodologies in the literature, with a subsequent selection and application of a factoring program developed by Page and Perry. The second objective was to develop a reliability improvement model given that a mathematical reliability expression did not exist. This was accomplished modeling a heuristic by Jain and Gopal, into a linear improvement model. Finally, …

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Preliminary Design Of A Model To Assess The Effect Of Space Surveillance Network (Ssn) Sensor Upgrades On Orbit Prediction Accuracies Relative To The U. S. Anti-Satellite (Asat) Mission, Daniel L. O'Brien Dec 1991

Preliminary Design Of A Model To Assess The Effect Of Space Surveillance Network (Ssn) Sensor Upgrades On Orbit Prediction Accuracies Relative To The U. S. Anti-Satellite (Asat) Mission, Daniel L. O'Brien

Theses and Dissertations

This study gives a basis for implementation of a model to assess the effect of proposed sensor upgrades to the Space Surveillance Network (SSN) to determine if more accurate orbital element set predictions by the Space Surveillance Center (SSC) can be obtained for U.S. anti-satellite (ASAT) targeting. Handoff orbital element set predictions to nearby ASAT facilities for single, low-orbit satellite passes over a single radar sensor are considered. Model development began with simulation of the selected satellites passing over the selected sensors producing baseline truth observations based on the NORAD simplified General Publications (SGP4) model. Sensor errors, in the form …

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Reducing Requirements Errors Through The Use Of Computer-Aided Software Engineering (Case) Tools And During Requirements Analysis, Marvin B. Key Jr. Dec 1991

Reducing Requirements Errors Through The Use Of Computer-Aided Software Engineering (Case) Tools And During Requirements Analysis, Marvin B. Key Jr.

Theses and Dissertations

This study investigated whether using CASE tools in the requirements analysis phase of software development reduced the software coding errors attributable to requirement analysis. A survey of the population gathered data as to the current practices and efforts in the use of CASE tools. The data was gathered in two groups: a control group and a sample group. The data was analyzed by group and in various combinations to obtain a greater understanding into population trends and tendencies. The results of the research indicate that the Air Force does not use CASE tools to any great extent. Also, error and …

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A Formal Definition Of The Object-Oriented Paradigm For Requirements Analysis, Andrew D. Boyd Dec 1991

A Formal Definition Of The Object-Oriented Paradigm For Requirements Analysis, Andrew D. Boyd

Theses and Dissertations

This paper develops a formal definition of the Object-Oriented paradigm for requirements analysis. The literature was surveyed for both formal and informal methods for conducting an Object-Oriented Requirements Analysis (OORA). The informal methods reviewed are: Bailin's, Shlaer and Mellor's, Booch's, and Coad and Yourdon's. The formal methods reviewed are: Bralick's, Z, and REFINE. None of the methods were found to be adequate for doing an OORA. A formal definition of an OORA, based on the concept of classes, is developed. The definition itself is presented as set and relation theory. A supporting graphical representation is also developed and presented. The …

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An Investigation Into The Use Of Computer-Assisted Instruction To Present Basic English Grammar Concepts, Frank E. Jones Dec 1991

An Investigation Into The Use Of Computer-Assisted Instruction To Present Basic English Grammar Concepts, Frank E. Jones

Theses and Dissertations

The purpose of this research was to develop a computer-assisted instruction (CAI) tutorial that would address basic grammatical concepts. The research consisted of four phases. The first phase was a review of applicable CAI literature, including theories, instructional and programming techniques, and previous research findings. The second phase was a survey of communication professors to determine the grammatical errors commonly committed by students. The third phase involved development of the tutorial content and the program software. The resulting tutorial presents basic grammar in terms of the three building elements of language (words, phrases, clauses) and the five functions they perform …

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Investigative Search Of Quality Historical Software Support Cost Data And Software Support Cost-Related Data, Brent L. Barber Dec 1991

Investigative Search Of Quality Historical Software Support Cost Data And Software Support Cost-Related Data, Brent L. Barber

Theses and Dissertations

The purpose of the study was to determine what software support cost data and software support cost-related data should and can be collected by the Air Force. In addition, the study was to determine how the subject data should be collected. The collection of this data is necessary in order to measure the accuracy and calibration requirements of the software support cost models used by the Air Force. The study found there was no standard set of data items, and no standard procedures in place for the collection of this data. In most cases data were available or easily accessible, …

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Structured Hypermedia Application Development Model (Shadm): A Structured Model For Technical Documentation Application Design, Peter W. Cassell Dec 1991

Structured Hypermedia Application Development Model (Shadm): A Structured Model For Technical Documentation Application Design, Peter W. Cassell

Theses and Dissertations

This research was conducted to determine how a Royal Australian Air Force technical maintenance publication could be transformed into a task oriented hypermedia application and to develop a model that could be used for future similar transformations. The model was developed following in-depth analysis of the existing USAF F-15E maintenance publication set and validation was conducted using a prototype developed in HyperWriter, a commercial hypermedia product. The prototype model was based around the performance of three maintenance tasks on an aircraft sub-subsystem and incorporated online user access to the necessary support data for task completion. Publication managers, producers, and users …

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Experimental Investigation Of Trailing Edge Crenulation Effects On Losses In A Compressor Cascade, Steven J. Decook Dec 1991

Experimental Investigation Of Trailing Edge Crenulation Effects On Losses In A Compressor Cascade, Steven J. Decook

Theses and Dissertations

The effects of blade trailing edge crenulations on wake losses in a compressor cascade were investigated at the Air Force Institute of Technology. The cascade used NACA 64-A905 blades with a turning angle of about 30 to model last row stators of an axial flow compressor. Three blade configurations were used: unmodified blades, blades with large crenulations, and blades with small crenulations. Wake losses and mixing were evaluated in four flow conditions, generated by combinations of increased freestream turbulence and sidewall boundary layer removal. Injection of air perpendicular to the inlet flow increased freestream turbulence from about 0.15% to about …

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An Approach For The Distance Delivery Of Afit/Ls Resident Degree Curricula, Mark C. Harris Dec 1991

An Approach For The Distance Delivery Of Afit/Ls Resident Degree Curricula, Mark C. Harris

Theses and Dissertations

This research developed an approach for adapting a resident graduate course, offered by the School of Systems and Logistics, for delivery to remote students through distance education resources and techniques. A review of literature-along with personal interviews of professionals from the fields of education, telecommunications, and technology-provided the information for a model of distance education and an assessment of AFIT's existing and near future resources that may be applied to distance delivery of graduate courses. Semantic network construction software was used to organize the information gathered for the distance education model. Key concepts were distilled from the conceptually multi-dimensional semantic …

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Improving Royal Australian Air Force Strategic Airlift Planning By Application Of A Computer Based Management Information System, Neil A. Cooper Dec 1991

Improving Royal Australian Air Force Strategic Airlift Planning By Application Of A Computer Based Management Information System, Neil A. Cooper

Theses and Dissertations

The purpose of this research was to propose a MIS to assist RAAF strategic operational airlift planning. The present manual approach suffers deficiencies in flexibility, consistency and timeliness. Airlift planning was first analysed and found to comprise activities of investigation, detailed static planning, implementation and dynamic planning, and review. Planning performance is measured by the effectiveness and efficiency of resulting airlift. Automation of planning functions was investigated, especially the routing and scheduling of airlift. USAF systems, including ADANS, were reviewed and applicability to the RAAF evaluated. Automation of planning functions was investigated, especially the routing and scheduling of airlift. USAF …

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An Expert System Advisor For Medical Evaluation Boards, Jerry S. G. Harrington Dec 1991

An Expert System Advisor For Medical Evaluation Boards, Jerry S. G. Harrington

Theses and Dissertations

Expert system technology has proven itself to be able to improve productivity and decision making in a variety of fields of endeavor. The purpose of this study was to determine if an expert system for medical evaluation boards (MEBs) could improve upon the processing of medical evaluation board cases. Research was conducted to develop an expert system and measure the capabilities of the system, both in terms of accuracy and timeliness of case completion of the medical evaluation administrators/clerks who were assisted by the system. The research methodology involved a three - phase approach. The objective of phase one was …

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A Comparative Study Of Dod And Civilian Hospital Inventory Management Systems, Karen A. Lemay Dec 1991

A Comparative Study Of Dod And Civilian Hospital Inventory Management Systems, Karen A. Lemay

Theses and Dissertations

The purpose of this thesis was to determine if one method of inventory management would standardize procedures and minimize costs for Department of Defense and civilian hospitals. This was accomplished by conducting a comparative analysis of inventory management systems, used at Wright-Patterson Medical Center, Wright-Patterson Air Force Base, Dayton, Ohio; Kettering Medical Center, Kettering, Ohio; and Evans US Army Community Hospital, Ft. Carson, Colorado. The literature review examined various inventory management methods used for both general and hospital specific inventories. The thesis concluded that, although different automated systems were used at the three hospitals studied, the basis of each inventory …

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Optimization Of Tangential Mass Injection For Minimizing Flow Separation In A Scramjet Inlet, Richard J. Kacik Dec 1991

Optimization Of Tangential Mass Injection For Minimizing Flow Separation In A Scramjet Inlet, Richard J. Kacik

Theses and Dissertations

With the reemergence of interest in air-breathing hypersonic propulsion, scramjet inlet efficiency has become an area of concern. The impingement of the engine cowl shock near the shoulder (expansion corner between forebody and combustor) may cause boundary layer separation which reduces inlet efficiency. Tangential mass injection (TMI) upstream of the shoulder has recently been tested to control this separation but without much parametric evaluation. To resolve this deficiency, a 2-D scramjet inlet model with variable length cowl, and TMI was built and tested in the WL Mach 6 High Reynolds Number Facility. Parameters varied were boundary layer thickness, TMI flow …

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A Standardized Software Reliability Measurement Methodology, Joseph J. Stanko Dec 1991

A Standardized Software Reliability Measurement Methodology, Joseph J. Stanko

Theses and Dissertations

Current Air Force practice is to perform Operational Test and Evaluation (OT and E) for each new weapons system. In support of this, Headquarters Air Force Operational Test and Evaluation Center (HQ AFOTEC) is responsible for measuring both suitability and effectiveness. While suitability is adequately measured, the current effort only addresses hardware effectiveness, or at best, system effectiveness. Since tools and metrics are in place for software suitability assessments related to OT and E (for example, software maintainability), there should be some effective way of measuring the operational effectiveness of software. Currently, HQ AFOTEC/LG5 has a data collection tool for …

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