Digital Commons Network^™

High-Resolution Tvd Schemes For The Analysis Of 1. Inviscid Supersonic And Transonic Flows. 2. Viscous Flows With Shock-Induced Separation And Heat Transfer, Mark A. Driver

Theses and Dissertations

Application of TVD schemes to both inviscid and viscous flows is considered. The mathematical and physical bases of TVD schemes are discussed. First and second-order accurate TVD schemes and a second-order accurate Lax- Wendroff scheme are used to compute solutions to the Riemann problem in order to investigate the capability of each to resolve shocks, rarefactions, and contact surfaces. Second-order finite-volume and finite-difference TVD schemes are used to obtain solutions to inviscid supersonic and transonic cascade flow problems. TVD schemes are shown to be superior to the Lax-Wendroff family of schemes for both transient and steady-state computations. TVD methodology is …

Multi-Layered Feedforward Neural Networks For Image Segmentation, Gregory L. Tarr

Theses and Dissertations

Artificial neural network image segmentation techniques are examined. The biological inspired cortex transform is examined as a means to preprocess images for segmentation and classification. A generalized neural network formalism is presented as a means to produce common pattern recognition processing techniques in a single iterable element. Several feature reduction preprocessing techniques, based on feature saliency, Karhunen-Loeve transformation and identity networks are tested and compared. The generalized architecture is applied to a problem in image segmentation, a tracking of high- value fixed tactical targets. A generalized architecture for neural networks is developed based on the second order terms of the …

A Delphi Forecast Of 1996 Roles: Air Force Institute Of Technology Information Resource Management Graduates Assigned To Base Level, David O. Block

Theses and Dissertations

Graduates of the Air Force Institute of Technology's Information Resource Management master's degree program who are subsequently assigned to base-level positions believe their IRM expertise is wasted in base administration roles that preclude the use of their up-to-date technical educations in managing automated information resources. This research forecasts the role AFIT IRM graduates assigned to base-level positions will need to fill by the year 1996. The research further determined what changes are necessary to resolve the perceived differences between current and forecast roles for these graduates. The Delphi survey method of forecasting was selected as an effective method of discovering …

An Expert System For Measuring, Interpreting, And Managing System Performance Factors For The Work Information Management System, Billy J. C. Irwin

Theses and Dissertations

This study develops an expert system for measuring, interpreting, and managing the Wang VS operating system performance factors for the Work Information Management System. The system's performance concerns least known to system administrators are identified. Of these, SHARER buffers and VTOC cache are identified as factors that can significantly impact system performance with little effort. A six step process is used in developing the expert system. Concept maps representing the structure of the Wang VS Disk Input/Output problem domain are provided. The expert system provides information about the system parameters, SHARER buffers and VTOC cache, and recommends main memory allocations. …

An Analysis Of The Information Requirements Of Conus Based Deputy Commanders For Maintenance, Daniel J. Green

Theses and Dissertations

The purpose of this research was to identify the information requirements of Air Force Deputy Commanders for Maintenance. It had three basic objectives: (1) identify the critical success factors that they monitor on a continuous basis, (2) identify similarities in those requirements for all DGMs and across major commands, and (3) determine if the application of information technology would enhance their decision making. Surveys were sent to all CONUS based Deputy Commanders for Maintenance. The study found that there were nine critical success factors that were used by a majority of all respondents. In addition, nine command-specific critical success factors …

Possible Application Of Quality Function Deployment In Software Systems Development In The United States Air Force, Craig R. Lamb

Theses and Dissertations

The objectives of the thesis were to determine whether the methods of Quality Function Deployment (QFD) could be used in the software development environment within the USAF, and whether or not this area should be researched further. The research was limited to the requirements analysis and definition phase. The different areas of study included a brief review of the structured analysis methodology, a detailed review of the QFD models currently being used in the product industries, a review of how QFD fits into the software development cycle, and specific software modifications to the QFD methodology. A review of some applications …

A Comparative Study Of Numerical Versus Analytical Waverider Solutions, Gregory O. Stecklein

Theses and Dissertations

The WL/FIMM explicit, Roe flux-splitting Euler algorithm is applied to the inviscid hypersonic flow over a parabolic-top waverider configuration optimized for Mach 10 at zero degrees angle of attack. An on-design grid refinement study is conducted to determine the asymptotic nature of the optimized flight parameter L/D. A parametric study of off-design conditions is conducted to determine flow perturbation effects on HSDT waverider theory. A validation of the Euler code is conducted through a comparison of the numerical data to analytical results derived by Rasmussen. The grid refinement study shows little effect on the inviscid calculation of the optimized parameter …

Finite Element Analysis Of A Riveted Repair On A Curved Composite Panel, Scott A. Hamilton

Theses and Dissertations

To analyze the current Aircraft Battle Damage Repair (ABDR) techniques, a finite element model (FEM) of a curved composite panel with a center cutout section was developed and verified against previously obtained modal test results. The FEM was modified using different methods to exhibit the effects of riveting on an aluminum patch to repair the section. The different methods were contrasted against each other and previously obtained modal test results. The panel, a (0/-45/+45/90) sub s layup of AS4/3501 graphite epoxy measuring 12 inches in height and 12.19 inches across its arc length with a 2 by 4 inch cutout …

Failure Characteristics Of Scs-6/Ti-24al-11nb Composite With A Circular Hole At Room And Elevated Temperatures, Joseph E. Overbeck

Theses and Dissertations

Off-axis loading of eight ply, unidirectional specimens with and without a circular hole determined the ultimate tensile strength of SCS-6/Ti- 24A1-11Nb composite at temperatures of 25°C and 650°C and fiber orientations of 0 degrees, 15 degrees, 45 degrees. Longitudinal moduli of the tested orientations compared closely to the rule of mixtures calculated values, and strengths compared closely to those predicted by the Tsai-Wu failure theory. The small diameter hole does not act as a stress concentrator, but merely reduces the material's strength in proportion to area loss. This result differs from those predicted by linear finite element analysis and orthotropic …

Design And Application Of An Object Oriented Graphical Database Management System For Synthetic Environments, John A. Brunderman

Theses and Dissertations

The Air Force Institute of Technology (AFIT) is investigating the use of synthetic environments for military applications under the sponsorship of Rome Laboratories (RL). Areas under investigation include mission planning, battle management and flight simulation. The work reported in this thesis focuses on the object-oriented design and implementation of the Graphical Database Management System (GDMS) used to support research in these areas. GDMS provides the data structures, file format and algorithms to manage and render hierarchical, three-dimensional, polygonal models. Flexibility and adaptability were key factors in its design. A secondary objective of this research was to demonstrate the functionality of …

Object-Oriented Analysis And Design Of The Saber Wargame, Christine M. Sherry

Theses and Dissertations

This thesis presents an object-oriented analysis and design of Saber, a theater-level computerized wargame, for the Air Force Wargaming Center, Maxwell AFB, Alabama. The analysis and design is based on a recently developed conceptual model, and existing land battle, and additional research. This thesis also begins the implementation process. The design was accomplished using an iterative, five step design process. Objects and operations were chosen and then encapsulated in Ada packages. This thesis also makes necessary changes to the land battle as described by the conceptual model and as the result of additional research. Sound software engineering principles were used …

Mathematical Writing: A Descriptive Study To Explore The Relationship Between Analytical / Creative Writing And The Understanding Of Mathematical Problem Solving In A Seventh-Grade Classroom, Shiela Ann Puffe

Theses and Dissertations

This naturalistic inquiry explored the relationship between writing and mathematical problem solving. The use of analytical writing and creative writing was examined to see if it was a beneficial heuristic for teaching understanding of mathematical problem solving in a seventh-grade class. The teacher acted as the principal researcher.

The treatment consisted of two distinct segments. Students wrote narrative, analytical accounts of their problem-solving process. They used a teacher-constructed study guide based on Polya's problem-solving framework (Understand the Problem, Devise a Plan, Carry Out the Plan, and Look Back / Evaluate) with metacognitive questioning as a guide for this writing. Students …

Comparative Analysis Of Guidance Algorithms For The Hyper Velocity Missile And Afti/F-16, Edward G. Rice

Theses and Dissertations

This project has provided me with endless intrigue. In considering the problem of guiding a hyper-velocity missile from a moving platform to a moving target, a common perception said it was just another Kalman Filtration design challenge. I began with lofty intentions of running a full up extended Kalman filter simulation but I became enthralled with the limited work available on the physical limitations of basic guidance algorithms. This became the emphasis of this project. The best filter scheme cannot overcome a guidance algorithms physical limitation. Only with an understanding of these limitations can one effectively integrate a guidance scheme …

The Effect Of Systematic Instruction In Mental Computation Upon Fourth Grade Students' Arithmetic Problem-Solving And Computation Ability., Gary William Thompson

Theses and Dissertations

Purpose. The main purpose of the study was to determine whether or not systematic instruction in mental computation would improve fourth grade students' written problem solving and computational abilities. Another purpose was to determine if gender would account for differences in problem solving and arithmetic computational ability among subjects of the control and experimental groups of the study, as determined by pre- and post-testing.Procedure. Pre- and post-tests were administered to control and experimental groups. The control group and experimental group subjects were fourth grade students from two elementary schools in an upper midwestern community of approximately 7,200. There were 51 …

College Preparatory Courses Offered And Percentages Of Graduating Seniors Attending Postsecondary Education In Selected Minnesota Public Senior High Schools., John Stewart Backes

Theses and Dissertations

This study examined the Minnesota public senior high school curricula (grades 10-12) and determined how many graduating seniors attended postsecondary education after high school. Specific research questions were (1) What percentage of the course offerings available in 1988-89 were college preparatory? (2) What percentage of the courses actually taught were college preparatory? (3) What percentage of the 1988 graduating seniors in Minnesota public schools attended postsecondary education after high school? (4) Did this percentage change during the previous decade?The study included all public school districts in Minnesota that reported 1988-89 Secondary Professional Staff Assignments to the Minnesota State Department of …

A History Of Teacher-Support Roles, David R. Leo-Nyquist

Theses and Dissertations

No abstract provided.

An Evaluation Of The United States Air Force Vehicle Burden-Sharing Programs, Harold E. Frary

Theses and Dissertations

The purpose of this research was to examine the issues surrounding the U.S. Air Force vehicle burden-sharing initiative with South Korea. In doing this, the study examined additional vehicle programs with the South Korean government as well as with NATO alliances to provide an historical background and insight into the concerns that faced vehicle managers with those programs. In addition, several transportation experts throughout the Department of Defense were interviewed for their perspective of the vehicle management issues which relate to these programs. This research revealed several issues that continue to concern transportation expert. These areas include the accurate and …

An Analysis Of Army Transportation Capability To Support The Distribution Of Liquid Propellant In Field Artillery Applications, John S. Lenart Jr.

Theses and Dissertations

This study applied a screening technique methodology to systematically obtain organizational consensus in the establishment and ranking of Army surface transportation performance measurement criteria and system design attributes. This performance evaluation model was then used to assess the feasibility of three potential liquid propellant logistics concepts. Two sample groups of subject matter experts from the Army's Transportation and Ordnance (Munitions) Corps participated in the research. The methodology consisted of nominal-interacting group processes, repeated used of the pair comparison instrument, and use of a scoring model to rank-order the ten attributes. Research findings supported the Army's qualitative commitment to ensuring environmental …

Stockless Medical Materials Management: Applications For The United States Air Force Medical Service, Thomas M. Harkenrider

Theses and Dissertations

The purpose of this research was to study stockless materials management in an effort to determine if it could improve the Air Force Medical Service's supply operations. The main result of this study was a decision support system (DSS) that would evaluate potential savings if stockless materials management were implemented in an Air Force medical treatment facility (MTF). In the process of developing the DSS, stockless materials management was studied in civilian hospitals that had previously converted to stockless materials management. Data included facility bed size, annual medical supply purchases, pre and post stockless medical supply full time equivalents (FTEs), …

A Validity Study On The Air Force Institute Of Technology Student Selection Criteria For Resident Master's Degree Programs, Daniel R. Sny

Theses and Dissertations

The purpose of this thesis was to determine the validity of the selection procedures that AFIT (Air Force Institute of Technology) uses for admission to their resident graduate programs by discovering if the variables considered by the AFIT registrar's office can predict success at AFIT. The study was based on a collection of 4507 academic records of US military officers, foreign officers, and civilians who attended as AFIT students between 1975-1987. The academic records provided the predictor variables to include each graduate student's undergraduate GPA, standardized test scores, and demographics. Through correlation analysis, this study examined the relationships between the …

A Review Of Selected Usaf Life Cycle Costing Models, Mark G. Twomey

Theses and Dissertations

This study examined the history of the development of life cycle costing (LCC) in the DOD and USAF, and reviewed 11 'mainstream' LCC models currently being used by the Air Force including the LSC, LCCH, ZCORE, CASA, PRICE H, PRICE HL, PRICE M, PRICE S, MLCC, Dyna-METRIC, and LCOM models. A literature search revealed that the last comprehensive reviews of LCC modeling in the USAF were conducted in the 1970s by the Joint AFSC/AFLC Commanders' Working Group on LCC and Rand. LCC's initial development, in the 1960s, was prompted by rapid increases in operating and support (O and S) costs …

A Policy Analysis Of Using Unit Costs As A Means Of Performance Measurement In The Air Force Science And Technology Program, Michael P. Avery

Theses and Dissertations

This study investigates the possible use of unit costs as a means of performance measurement in the Air Force Science and Technology (S and T) program. Using a policy analysis methodology, the author breaks the analysis into four phases. The first phase called understanding the problem and incorporates the theory of management control systems, budgets, resource management systems, and identifies what the S and T program encompasses. The second phase is called developing policy options and identifies three distinctly different policies that satisfy the need for getting performance information into the hands of decision-makers. The third phase is called determining …

The Development And Retention Of Critical Thinking Dispositions Among Students Of The Air Force Institute Of Technology Graduate Management Programs, Luke J. Schaub

Theses and Dissertations

This effort analyzed the development and retention of critical thinking dispositions in students of the Air Force Institute of Technology's School of Systems and Logistics graduate management program. The Myers-Briggs Type Indicator was used as a measure of subjects' dispositions. Pre- and post- test surveys were administered when subjects entered and exited the program, and a follow-up administered two to five years later. The pre- and post-tests were administered to 427 subjects and the follow-up to 201 of those subjects. It was found that subjects increased their preference for logical, objective decision-making while enrolled in the program. Subjects also increased …

Comparison Of The Operational Characteristics Of The Theory Of Constraints And Just-In-Time Scheduling Methodologies, Lynn A. Sines

Theses and Dissertations

This study compared the characteristics of scheduling using two approaches: Just-in-Time (JIT) and the Theory of Constraints (TOC). Computer simulation was used to evaluate changes in the throughput of the system due to system variability and varying work-in-process (WIP) levels. The independent variables were processing time, probability of failure, and WIP level. The literature search revealed that these variables impacted performance of JIT systems. Simulation models of three different production systems were developed to determine if the TOC scheduled system would provide greater or equivalent throughput for equivalent levels of WIP, and to determine if the system production flow path …

Improved Decision Making Through Group Composition, William E. Page Iii

Theses and Dissertations

This experimental study attempted to prove that teams formed with dissimilar personality types would have better decision making than teams which were not formed by dissimilar types. The Myers-Briggs Type Indicator, based on Jung's Theory of Psychological Type, was used to determine the subject's personality type preferences. Subjects' perceptions of team processes were also investigated. The sample population consisted of military officers and civil servants who attended the Advanced Program Management course at the Air Force Institute of Technology. Decision making effectiveness was determined from team performance on the Time-by-Event-by-Member-Pattern-Observation system (TEMPO). The design for this research consisted of comparing …

Analysis Of The Cash Recovery Rate's Potential Application In Determining The Social Cost Of Capital, Francis J. Geiser Iii

Theses and Dissertations

This study explored the potential application of the cash recovery rate in determining the social cost of capital. It specifically investigated the results of using cash-recovery rate-based, internal rate of return-estimating relationships, which were formulated under assumptions of constant investment growth rate, to estimate internal rates of return for simulated firm-level financial data generated using both exponentially increasing and sinusoidal investment growth rates. An extensive literature review is used to build a analytical link between the need for updating the social discount rate, capital budgeting decisions based on internal rates of return, and the proposed behavior of the cash recovery …

An Investigation Of Project Management Techniques For Scheduling Raaf Depot Level Maintenance, Kerry M. Bayley

Theses and Dissertations

This research investigates scheduling performances of commercial project management software. It is based on difficulties that the Royal Australian Air Force experienced in evaluating microcomputer-based packages in maintenance task scheduling of aircraft undergoing Depot Level Maintenance. A literature review found only one paper quantifying commercial software performances. No standard performance metrics or test data were found. Several packages were evaluated using a common set of 110 single-project resource- constrained networks. The performance measure used was closeness to optimally minimum Total Durations. No package performed best on all problems. On average, the best produced schedules 5.2% longer than optimal, with 95 …

An Application Of Interactive Computer Graphics To The Study Of Inferential Statistics And The General Linear Model, Stephen D. Pearce

Theses and Dissertations

This research created a learning environment, known as the Pearce Projection Modeling Environment (PPME) which is used as a tool by a teacher and student. The PPME was developed in an effort to create a new approach to the study of the General Linear Model through a constructive and projective, geometric approach. While the geometric approach to the GLM was developed over the past century, it has not been used extensively because of the inherent complexities associated with visualizing vector spaces. With the PPME, visualization is accomplished effortlessly. The PPME is a computer program that allows the student to enter …

Education Necessary For Air Force Software Managers To Use The Ada Programming Language And Software Engineering Effectively, James W. Worley Jr.

Theses and Dissertations

This research investigated the perceived Ada and software engineering education needs of software managers throughout the Air Force and provided recommendations to Air Staff for developing the education. Since the Department of Defense mandated all DOD agencies use the Ada programming language for software development, the education of the personnel who have to support the policy has lagged behind the implementation Ada is not a simple language to use and is only fully effective if used with sound software engineering principles. A survey was given to Air Force mid-level personnel who manage software in some capacity. Of the software personnel …

A Model For Estimating Aircraft Recoverable Spares Annual Costs, Phillip L. Redding

Theses and Dissertations

This thesis covers three objectives: (1) develop a background reference document concerning recoverable spares cost estimating; (2) evaluate a representative sample of existing spares cost models; and (3) use aircraft physical and performance characteristics to develop a model for estimating annual replenishment spares cost. A condemnations cost estimating relationship (CER) was developed first and then both a CER and spreadsheet generated factors which related condemnations to replenishment spares costs were developed. For the condemnations CER, only logarithmic transformations provided statistically acceptable results, and even these models exhibited wide prediction intervals due to large amount of variability in the CER databases …