Engineering Commons^™

A Prototype Meta-Language And Automated Translator For Decision Analysis Problem Formulation, Jerry R. Puyear

Theses and Dissertations

This thesis research effort develops a prototype meta-language for decision analysis problem description and automated software to translate the meta-language into a format useable by decision analysis software solvers. MELDA, the metalanguage developed, makes use of special symbols to provide a succinct language for the automation environment yet provides the means for user comprehension. Complete syntax and implementation rules are included. The MELADA translator software developed, DAT, stores the data given by MELADA in a file using prototype standard format, DASF, designed to hold all required data to solve a problem. DAT provides error checking and a message output file. …

A Network Flow And Goal Programming Approach To Modeling The Impact Of Pre-Accession Training To The Trained Personnel Requirements Process, William J. Beveridge

Theses and Dissertations

HQ ATC was tasked to analyze the impact of pre-accession training to the Trained Personnel Required (TPR) and training production process. Pre- accession training is a policy of providing contracted initial skills training to enlistees prior to entering basic military training. The purpose of this study was to develop a method to model the impact of pre-accession training. A network modeling and goal programming approach was used. Comparisons between the current training policy and a pre-accession training policy were made. Sensitivity was conducted on the impact of a balk rate on the new policy. The balk rate is the percent …

Saber: A Theater Level Wargame, William F. Mann Iii

Theses and Dissertations

This thesis provides a foundation to build a new theater level computerized wargame for the Air Force Wargaming Center, Maxwell AFB, AL to replace the Theater War Exercise (TWX), also known as Agile. Given a recently developed land battle, this thesis' effort links US Air Force doctrine with a conceptual model's framework and designs a new air battle module. The integration of both the air and land battles forms a new game, Saber. This thesis redefines the ground combat units of the land battle, and adds theater air defense units, bases and aircraft packages. This thesis introduces stochastic attrition between …

The Utility Of Elliptical And Circular Confidence Regions For Hfdf Receivers, Paul T. Nemec

Theses and Dissertations

This thesis investigates HFDF confidence region (CR) shape exhibited by geolocations in a search-and-rescue context. In Phase I, a Keeney-Raiffa multiattribute utility function was developed which allowed an analytical measure of preference between elliptical and equivalent- probability circular CRs. Phase II utilized a likelihood approach to establish CR shape for sample operational geolocations having multiple points of bearing intersections. For 12 sample Phase I geolocations, the elliptical CR always had higher utility than its corresponding circular CR. For accepted sample geolocations, a preference condition was developed whereby a circular CR would only be preferred over the corresponding elliptical CR if …

Thermo-Mechanical Fatigue Of A Fiber Reinforced Titanium Aluminide Composite, Mark A. Bates

Theses and Dissertations

The thermo-mechanical fatigue behavior of a specific unidirectional fiber reinforced titanium aluminide composite was investigated. Three test specimens were subjected to in-phase thermo-mechanical cycling and four to out- of-phase thermo-mechanical cycling. The applied maximum mechanical stresses ranged from 500-800 MPa. The stress ratio of 0.1 was used for all tests. The temperature range was from 150-650 C and the resulting fatigue lives were in the 58-1487 cycles range. The out-of-phase test specimens failed sooner compared to their respective in-phase counterparts. In order to find out why, the test results were analyzed using a simple micromechanics analysis and compared. The fracture …

A Prolog-Based System For Hardware Verification, Kevin L. Sparks

Theses and Dissertations

With the expanding number of components provided on a single digital chip, verification of digital designs is becoming a major problem. The more circuits one places on a single chip, the greater the number of input/output combinations which need to be checked. A paper by Barrow in 1984 discusses a Prolog-based hierarchical formal verification system which he calls VERIFY. Barrow provided a lot of information on what VERIFY can and cannot do, and on projected enhancements. He does not, however, mention how VERIFY actually performs the task of formal verification. This thesis will provide a description of one possible implementation …

Optimal Iterative Task Scheduling For Parallel Simulations, Joann M. Sartor

Theses and Dissertations

The ultimate purpose of this research is to reduce the time needed for execution of parallel computer simulations. In particular, the impact of task assignment strategies is determined for parallel VHDL circuit simulations. The classical scheduling problem, which assigns n precedence-constrained tasks to m processors is NP-complete in all but the simplest cases. The problem of assigning simulation tasks is further complicated by the iterative nature of computer simulations: each task is required to execute multiple times as the simulation executes. This investigation develops a polynomial-time algorithm (the level strategy) which provides optimal assignment for iterative systems with specific constraints. …

A Fully Coupled, Automated Formation Control System For Dissimilar Aircraft In Maneuvering Formation Flight, Paul R. Rohs

Theses and Dissertations

This study developed a fully automated formulation control system, capable of controlling a number of like or dissimilar aircraft in maneuvering formation flight. C-130 fixed wing aircraft and H-53 helicopters were modelled in various formulations and simulated through a mix of maneuvers. External formation guidance was assumed as a single data burst of nominal function guidance commands and separation distances for each wing aircraft in the formation. No communication was assumed between formation aircraft. Wing aircraft track lead aircraft maneuvering with an ideal on-board sensor, maneuvering to maintain relative position. It was determined that lead aircraft inputs must be attenuated …

A Navigation Reference System (Nrs) Using Global Positioning System (Gps) Aiding, Richard D. Stacey

Theses and Dissertations

To quantify the performance abilities of existing or proposed navigation systems, the U.S. Air Force has for the last several years compared the performance of the system under test to the performance of a baseline navigation system known as the Completely Integrated Reference Instrumentation System (CIRIS). CIRIS obtains a highly accurate navigation solution by combining the output from three major subsystems: inertial navigation system (INS) information, barometric altitude information, and range and range-rate data from ground transponders which have been precisely surveyed. Although the navigation solution produced by CIRIS is highly accurate, it will soon be inadequate as the standard …

Development Of An Angular Distribution Function For The Study Of Atomic Lattice Structures Used In Atomistic Simulation, David Wesley

Theses and Dissertations

An angular distribution function (ADF) was developed as a tool to be used in atom simulation. The ADF lets us easily distinguish between different lattice structures for systems of atoms by looking at the distribution of bond angles. The ADF is also a useful tool for determining the amount of order in a system. First, model structures of simple cubic, FCC, BCC, and diamond were developed. Then, the ADF was used on these model structures so that a set of model graphs of the ADF could be used to compare to real systems. Finally, simulated systems of Ferric Titanate, Nickel …

New Modified Anderson-Darling And Cramer-Von Mises Goodness-Of-Fit Tests For A Normal Distribution With Specified Parameters, Goksel Kahya

Theses and Dissertations

This thesis improves the powers of the Anderson-Darling and Cramer-von Mises goodness-of-fit tests using the mean rank and the median rank plotting positions. A Monte Carlo simulation of 5000 repetitions is used to generate the critical values from n =4 through n =80 for certain significance levels. An extensive power study is performed to compare the powers of the modified tests to the known tests for the uniform, the exponential, the double exponential, the lognormal, and the Weibull distributions. The power of the A-D tests modified by the median rank plotting and the mean rank plotting position are approximately 0.01% …

A Goodness-Of-Fit Test For A Family Of Two Parameter Weibulls With Known Shape Using Minimum Distance Estimation Of Parameters, John S. Crown

Theses and Dissertations

This research is to produce a modified Anderson-Darling goodness of fit test for the Weibull distribution when the location parameter is found by minimum distance estimation, the shape parameter is assumed known, and the MLE is used for the scale parameter. The critical values for the Anderson-Darling test are generated via Monte Carlo simulation when both the Anderson-Darling and Cramer-Von Mises distance statistics are minimized. These critical values are then used for a power study. The Monte Carlo simulation used 5000 repetitions for sample sizes of 5,8,12,15,16,20 and 25 with the Weibull shape parameter of . 5(.5)4.0. The power study …

Location And Routing Of The Defense Courier Service Aerial Network, Steven F. Baker

Theses and Dissertations

This study extends work done by the Military Airlift Command's Analysis Group on reducing the operating costs of the Defense Courier Service aerial network. The study's primary focus is to minimize those costs by varying the number and location of servicing depots, and the routes flown from those depots. The theoretical algorithm used in the methodology is an expansion of Laporte's (1986) formulation of the multiple depot multiple travelling salesmen facility-location problem. Multiple servicing frequency is addressed by clustering co-located demands with Kulkarni's (1985) subtour breaking constraint. Vehicle range is considered by redressing a shortfall of the subtour breaking constraint, …

The Development Of An Officer Training School Board Score Prediction Method Using A Multi-Board Approach, Sandra C. Niemi

Theses and Dissertations

One phase in the Officer Training School (OTS) selection process is meeting a selection board. Recruiting Services (HQ ATC/RS) currently uses a regression model (based on data from one board) to evenly distribute 'quality' among the different panels in the selection boards. HQ ATC/RS wanted a method of predicting board scores based on data from multiple boards. This study used the results from eighteen boards and 9215 applicants to develop and validate a multi-board regression model for each of five application categories. Comparisons between the two models showed mixed results. In two categories, non- rated operations and technical, the single-board …

Locating Direction Finders In A Generalized Search And Rescue Network, Jean M. Steppe

Theses and Dissertations

A multiobjective linear programming approach is applied to the problem of locating receiving stations and HFDF receivers in a search and rescue network in order to maximize the expected number of distress signals that are geolocated. The multiobjective formulation is made up of two contrasting objectives: one maximizes the expected accurate lines of bearing, and one minimizes the excess coverage in the network. The individual objectives are weighted and combined into a composite objective function. The resulting problem is expressed as a two-stage network flow problem and is solved using SAS LP with a limited number of binary variables. The …

A Solution Methodology For The Variable-Level Scheduling Problem, Dennis R. Benson

Theses and Dissertations

This study looked at a specific scheduling problem for a Department of Defense agency. A heuristic algorithms was developed to solve a general variable-level scheduling problem and was applied to this specific problem. This heuristic used linear programming and integer programming to find the minimum number of weekly billable hours for five alternative schedules. The best alternative schedule was further developed into a spreadsheet designed, squad level, master schedule. The result of this study was a proposed schedule that would save the United States government 8.2% of their security costs for this one part of the governmental agency. These savings …

An Interactive Life Cycle Cost Forecasting Tool, John A. Gibson Iv

Theses and Dissertations

Enhancements were applied to an existing tool designed to estimate life cycle costs. These enhancements provide greater ease of data manipulation, additional options in developing models, and the ability to make modifications to suit the needs of the user. Life cycle costs can be generated quickly and easily. Analysis proved the amount of work done by the computer could be reduced with no loss of information. Additionally, the paths available to the user are shown graphically through flow charts--aiding in the learning process. The efforts of the user can now be directed towards developing models instead of spending those efforts …

Investigation Of A Zero-One Integer Programming Approach To Automating The Scheduling Process At The Usaf Test Pilot School, Lisa M. Hassel

Theses and Dissertations

This thesis investigated models that could be used to determine a feasible schedule for the Test Pilot School (TPS) training program and form the basis for an automated scheduling system. The TPS problem is formulated as a 0-1 integer linear program and is solved using preprocessing techniques and the Branch-and-Bound algorithm. The method produced feasible solutions for small problems that equate to portions of the TPS schedule but cannot efficiently solve large problems like the full TPS problem. More investigation should be conducted to alter the method developed in the study so it could be used for large problems. A …

An Assessment Of The Accuracy Of Semi-Empirical Quantum Chemistry Calculations Of The Mechanical Properties Of Polymers, James R. Shoemaker

Theses and Dissertations

The ultimate mechanical properties of polymers, assuming perfect morphology, will be limited by the mechanical properties of a single, ideal polymer chain. Previous calculations of polymer chain moduli using semi- empirical (SE) quantum chemistry methods have resulted in modulus values much higher than experimentally measured. This study investigated the error in the calculated inherent to the method of calculation by comparing SE results for C-C bond potentials in two well characterized polymers, polyethylene and polydiacetylene. It was found that the SE calculation systematically overpredicted bond stiffness in these polymers by approximately 25% to 30%. This is the upper limit on …

An Environmentally Controlled Chamber For The Study Of Radon Detection, William R. Wharton Jr.

Theses and Dissertations

A system was developed to dynamically control and monitor the environment and radon concentration within a glovebox chamber for the study of radon. The system is designed around a personal computer workstation which automates the entire system. The radon concentration is determined by monitoring the count rate from radon and its progeny which are continuously circulated from the radon chamber through a Lucas Cell detection system. This information is then used as a base for controlling a radon injection system. When the concentration within the glovebox drops, the system injects a precisely-measured volume of high activity radon gas into the …

Development Of A Personal Computer Based Approach To Aircraft Parameter Identification, Mark S. Erickson

Theses and Dissertations

This thesis develops and tests a personal computer based approach to the aircraft parameter identification problem. The approach was tested analytically at the Air Force Institute of Technology, Wright-Patterson AFB, Ohio. These tests were conducted using simplified short period approximation and second-order transfer function models of longitudinal aircraft response. Initial evaluations were accomplished using simulated, noise free data. The longitudinal aircraft model was modified prior to flight test, for both convenience and necessity. This more complex model was evaluated during a flight test program at the USAFTPS, Edwards AFB, California. A T-38A aircraft was used as a tool to demonstrate …

The Self-Shielding Of Fallout Gamma Rays By Terrain Roughness, Mark S. Herte

Theses and Dissertations

The study presents a first order calculation of the self-shielding of nuclear weapon fission fragment gamma rays by surface roughness (microscopic terrain irregularities). To simulate fallout particles, polymer microspheres were deposited on slides containing samples of soil, concrete and asphalt roofing shingles. Scanning electron microscopy was used to photographically map the surfaces. The thickness of surface irregularities at various angles was measured by converting the photographs to digital images. Measurements showed a dependence upon the surface type, but not upon particle size. Average values of the measurements were modelled using a homogeneous buried source. With this geometry, dose rates were …

The Optimal Location Of Geodss Sensors In Canada, Pierre J. Forgues

Theses and Dissertations

This thesis studies the maximal coverage p-median and the set covering facility location problems as applied to the GEODSS location problem. The classical single-objective mathematical formulations of the p-median and set covering problems are converted into network-flow formulations and various solution methods are developed using a scaled-down version of the GEODSS problem. The next step is the introduction of a second criterion function into the problem. This second function consists of minimizing the sum of the variance in coverage at the selected locations. Research reveals the deficiencies of MOLP (multiobjective linear programming) techniques in generating the efficient frontier of an …

A Combined Gel Entrapped And Membrane Attached Microbial Process For Biodegrading Organic Compounds, Fayaz Saifuddin Lakhwala

Dissertations

A comparative study has been performed between two bioreactors treating phenol, one using calcium alginate entrapped microorganisms, and the other using microorganisms attached on the surface of a polymeric membrane. Laboratory experiments conducted in batch recirculation mode, as well as a continuous feed mode, showed that the calcium alginate bio-bead reactor is more efficient in treating high feed concentrations of phenol, while the membrane bioreactor is more effective in the lower concentration regime (less than 150 ppm). In batch recirculation mode, the reaction rates (expressed as mg phenol/hr*gm dry cells) in the membrane reactor are an order of magnitude higher …

Thermodynamics Of Strong Electrolyte Solutions : Prediction Of Osmotic Coefficients By Pair Correlation Function Method, One Kwon Rim

Dissertations

Thermodynamic properties (osmotic coefficients) of strong electrolyte solutions have been studied by the method of statistical mechanics. First the charged soft sphere potential is developed based on the Pauling type model. Next the charged soft sphere potential is converted to the thermodynamically corresponding charged hard sphere potential by way of the perturbation method developed by Verlet and Weis. Simultaneously, the radial distribution function is developed by modification of the Exponential theory through introduction of the Stillinger-Lovett moment condition. The effective hard sphere diameter values calculated by the perturbation method are combined with the modified Exponential theory, and these quantities are …

On Local Stresses And Spring Constants Of A Sphere-Nozzle Connection, Ban-Li Lyow

Dissertations

This dissertation studies the local stresses and spring constants of a spherical shell with a nozzle attachment when it is under various loadings, namely radial force, overturning moment, horizontal shear force, and torsional moment. Because of the mathematical difficulty in modeling the nozzle-sphere configuration, particularly with nozzle opening, the finite element method (ANSYS package) is utilized in this study. The model used in this study is a quadrilateral thin shell element model when the γ_s (spherical radius/thickness) value is larger than 10. Otherwise the isoparametric solid element is used. The resulting stresses are basically biaxial state of stresses. It …

N-Cross Coupled Phase Locked Loops, Joseph C. Aboukhalil

Theses

Interference cancelation has been mainly performed using arrays, in an important issue in communication both array and spatial cancelation and time domain approach were used. In array applications, depth of cancelation may dependent on the interferences to background power ratio and their spatial distributions. Also, array cancelers are inadequate when the signals are less than an array beamwidth apart. The latter was dealt with using supperesolution and eigenanalysis methods. Different time domain methods were used in the past. Among them what is termed Cross-Coupled PEL. It is an arrangement of two PLL each one is locked on and tracking one …

Fault Tolerant Clos Network, Preet Mohan S. Ahluwalia

Theses

Multistage interconnection networks, or MINs, provide paths between functional modules in multiprocessor systems. The MINs are usually segmented into several stages. Each stage connects inputs to appropriate links of the next stage so that the cumulative effect of all the stages satisfies input-output connection requirements.

This thesis deals with a fault tolerant Clos network. The fault tolerance technique involves addition of extra switches per stage to compensate for any switch failure The reliability analysis of both ordinary and fault tolerant Clos networks is presented. The optimal number of extra switches required to get the best reliability results has been analyzed.

Multiresolution Techniques : Laplacian Pyramid Coding And Its Comparison With Subband Coding, Danmei Chang

Theses

The multiresolution pyramid and related structures have been developed as intermediate representations between the purely frequency domain and purely spatial domain. In this thesis. we discuss two important pyramid structures which are often used in multiresolution representation: Laplacian pyramid and subband coding.

Laplacian pyramid. a typical pyramid structure, is studied in detail. By means of software implementation. we obtain a comprehensive understanding of its features and applications in image representation and data compression. Several modifications of pyramid structure are used to compress the data dynamic range, reduce the computational complexity and improve performance. Performance of the conventional Laplacian pyramid and …

Centrifugal Modeling Of Leaking Underground Storage Tanks, Kuo-Neng George Chang

Theses

There are between 2 to 3.5 million Underground Storage Tanks (UST) located through this nation. Most of these tanks store gasoline and fuel oil. Many tanks in fact are or will soon be leaking, thus making them one of the major sources of groundwater contamination in USA. The fate and transport of chemicals from the leaking USTs is estimated from mathematical models. A major difficulty in these modeling efforts has been a crucial lack of information concerning the constitutive relationships governing multiphase contaminant movement.

Centrifugal modeling is an alternative to mathematical modeling, which may give an insight to the problem …