Digital Commons Network^™

The Application Of Kriging For Controlled Minimization Of Large Data Sets, Christopher Brodkin

Theses and Dissertations

Frequently, the quantity of data available is much greater than that which can be manipulated in an efficient and timely manner. This can cause several problems. The first, and probably most critical, problem is the excessive on-line storage needs of these huge data sets. Secondly, in the computer animation field, huge data sets may require excessive computational time for generation of each frame of a computer animation. Thirdly, computer screens have a limited resolution and need too much computational time removing excessive detail from images generated with a higher resolution than can be displayed. Lastly, too much time is required …

An Object-Oriented Database Implementation Of The Magic Vlsi Layout Design System, Timothy M. Jacobs

Theses and Dissertations

This thesis attempts to prove that the commercially available Object Store data management system provide the performance and functionality necessary to support a complex engineering design system. This is accomplished by modifying the Magic VLSI circuit layout design system to eliminate its current Unix file data management system and replace it with Object Store. The approach to this research effort includes a design recovery of the Magic system and identification of its ket data management functions. These functions are then modified to take advantage of the database management facilities of Object Store. Additional code is added to instrument performance measurement …

An Animated Graphical Postprocessor For The Saber Wargame, Gary W. Klabunde

Theses and Dissertations

One of the most cost effective ways to learn and home the skills necessary to conduct and win a war is through the use of realistic computer simulations of conflict, or wargames. The Saber wargame was developed for just this purpose. Saber is a multisided, theater-level simulation developed by the Air Force Institute of Technology for the Air Force Wargaming Center. It models conventional, nuclear, and chemical warfare between aggregated air and ground forces. To aid in the realism, the effects of logistics, satellites, weather, and intelligence are represented. Saber provides an avenue for senior level joint service officers to …

Establishing A Methodology For Evaluation And Selecting Computer Aided Software Engineering Tools For A Defined Software Engineering Environment At The Air Force Institute Of Technology School Of Engineering, Jody L. Mattingly

Theses and Dissertations

This thesis identifies the software engineering environment (SEE) as it exists at the Air Force Institute of Technology (AFIT) School of Engineering. It also describes the software process model employed and the software development methods presented as part of the curriculum. Based on this information, criteria was established to evaluate computer aided software engineering (CASE) tools being considered for integration into the SEE. Each criterion was weighted to indicate its importance when selecting CASE tools. The criteria were further used to establish a methodology to be used to evaluate and select the CASE tools under consideration as well as future …

Lqg Control Of A Deformable Mirror Adaptive Optics System With Time- Delayed Measurements, David J. Anderson

Theses and Dissertations

This thesis proposes a linear quadratic Gaussian (LQG) control law for a ground-based deformable mirror adaptive optics system. The incoming image wavefront is distorted, primarily in phase, due to the turbulent effects of the earth's atmosphere. The adaptive optics system attempts to compensate for the distortion with a deformable mirror. A Hartman wavefront sensor measures the degree of distortion in the image wavefront. The measurements are input to a Kalman filter which estimates the system states. The state estimates are processed by a linear quadratic regulator which generates the appropriate control voltages to apply to the deformable mirror actuators. The …

A Walsh-Domain Adaptive Filter, Larry J. Duvall

Theses and Dissertations

Two Walsh-domain dyadic convolution adaptive filters are developed using a circular convolution frequency-domain filter (FDF1) and the Fast LMS adaptive filter (FDF2): WDF1 and WDF2 respectively. General theory of time- domain adaptive filters and a theoretical analysis of the FDF1, FDF2, WDF1, and WDF2 filters are presented. WDF1 and WDF2 software implementation are shown to be error free. A time-domain filter (TDF) and a FDF2 frequency-domain filter (FDF) are implemented for comparison testing. The WDF1, WDF2, TDF, and FDF filters are tested using time-shifted sinusoidal and rectangular noisy and noiseless signals. WDF1 and WDF2 are shown to converge faster and …

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 …

Evaluation Of Scalar Value Estimation Techniques For 3d Medical Imaging, Rob W. Parrott

Theses and Dissertations

Scalar value estimation in 3D medical imaging increases data resolution for enhanced renditions and corrects inaccurate surface formations. Accurate estimations are vital because clinical assessment is often aided by examination of 3D medical images. This thesis explores different estimation techniques and introduces the geostatistical estimation technique called kriging to the field of 3D imaging. Kriging theory claims to be the optimal estimator-- better than the standard deterministic methods commonly used. The techniques investigated are linear interpolation, trilinear interpolation, tricubic interpolation, and kriging. This research investigates scalar value estimation in the volume pre-processing operation of slice interpolation and in a surface …

Control Of A Large Flexible Space Structure Using Multiple Model Adaptive Algorithms, John A. Gustafson

Theses and Dissertations

The development and performance of moving-bank multiple model adaptive estimation (MMAE) and control (MMAC) algorithms for quelling vibrations induced in the SPICE 2 space structure are analyzed in this thesis. The structure consists of a large platform and a smaller platform connected by three legs in a tripod fashion. The model supplied by Phillips Laboratory, Kirtland AFB is used to develop a truth model and multiple reduced ordered filter models. The filter models are developed from modal analysis and internally balanced techniques. Deviations of the line-of-sight vector from the center of the large platform to the center of the smaller …

Investigation Of The Effects Of Aeroelastic Deformations On The Radar Cross Section Of Aircraft, Samuel D. Mckenzie

Theses and Dissertations

The effects of aeroelastic deformations on the radar cross section (RCS) of a T-38 trainer jet and a C-5A transport aircraft are examined and characterized. Realistic representations of structural wing deformations are obtained from a mechanical/computer aided design software package called NASTRAN . NASTRAN is used to evaluate the structural parameters of the aircraft as well as the restraints and loads associated with realistic flight conditions. Geometries for both the non-deformed and deformed airframes are obtained from the NASTRAN models and translated into RCS models. The RCS is analyzed using a numerical modeling code called the Radar Cross Section - …

Incorporation Of Differential Global Positioning System Measurements Using An Extended Kalman Filter For Improved Reference System Performance, William J. Negast

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 information from three major subsystems: inertial navigation system (INS) information, barometric altitude information, and range and range-rate information 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 against …

Function Prediction Using Recurrent Neural Networks, Randall L. Lindsey

Theses and Dissertations

A fully recurrent neural network was applied to the function prediction problem. The real-time recurrent learning (RTRL) algorithm was modified and tested for use as a viable function predictor. The modification gave the algorithm a variable learning rate and a linear/sigmoidal output selection. Verifying the networks ability to temporally learn both the classic exclusive-OR (XOR) problem and the internal state problem, the network was then used to simulate the frequency response of a second order IIR lowpass Butterworth filter. The recurrent network was then applied to two problems: head position tracking, and voice date reconstruction. The accuracy at which the …

The Tone System Of Foodo Nouns, Gray C. Plunkett

Theses and Dissertations

This thesis presents an autosegmental analysis of the tone system of the nouns of Foodo, a Guang language of Benin. The goal is to give an analysis of the tone system of nouns that will account for all the surface tonal phenomena by positing two underlying tones. Foodo nouns consist of a stem together with its class prefix and/or suffix; while tonal alternations in prefixes are easily explained by two tone rules, the suffixes exhibit rather complex alternations. Many of the theoretical assumptions of lexical phonology, (especially the view that most lexical rules are cyclic and Kiparsky's Elsewhere Condition) allow …

Grand Forks Housing Study, John Leland Sauter

Theses and Dissertations

No abstract provided.

Silicon Carbide Thin Film Deposition By Reactive Ion-Beam Sputtering, Larry G. Sills

Theses and Dissertations

In this study, hydrogenated amorphous silicon carbide thin films were deposited by reactive ion-beam sputtering under varying conditions to determine whether a film's optical properties can be controlled, focusing on refractive index. Using a Kaufman type ion source to sputter a pure silicon target, three distinct series of films were grown. The first series varied the mixture of methane and argon used in the ion-beam. holding all other parameters constant. For the second series the gas mix was fixed, and only the beam energy (beam voltage) was varied. The final series also varied beam energy, but was grown with a …

The Relationship Of Obsessive-Compulsive Characteristics To Impression Accuracy And Perceptions Of Self And Others, Jill M. Plevell-Omdahl

Theses and Dissertations

The identification of methodological and statistical difficulties in previous impression accuracy research has necessitated that the role of personality in impression accuracy be reinvestigated. The present research addressed: (1) the impact of obsessive-compulsive personality traits on impression accuracy; and (2) subject perceptions of actual self, ideal self, others, and others' perceptions of them.

This study utilized a 2 x 2 x 2 design. Independent variables included: (1) judge vs. observer status; (2) high vs. low obsessive-compulsive traits; and (3) first vs. second session. Dependent variables included subject ratings on the OSCARS (Versions 1-4), designed to measure the obsessive-compulsive tendencies in …

A Catalog Use Study Of The Library Online Catalog, Randy Pederson

Theses and Dissertations

No abstract provided.

A Certified Public Accountants Key Considerations In Establishing A Personal Financial Planning Practice, Darrell A. Flynn

Theses and Dissertations

No abstract provided.

Swatter (Space-Based Weapons Against Tactical Terrestrial-Based Resources): A Design For Integrating Space Into A Theater Level Wargame, Duane R. Cozadd

Theses and Dissertations

This thesis provides the foundation to expand the newly developed theater level computerized wargame, SABER, at the Air Force Wargaming Center, Maxwell AFB, Alabama to include space conflict at the theater level of simulation. Building upon the recently completed SABER, this thesis effort expands the conceptual framework of the model by integrating the dynamics of space warfare into the current theater level model. This expansion forms a new game called SWATTER. This thesis adds the space units required to integrate the land and air battles with the possible interactions from space. This thesis expands the stochastic attrition processes to include …

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 …

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. …

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 …

Effects Of An Exercise Program On Mentally Impaired Older Adults In A Long-Term Care Facility, Linda D. Bane Frizzell

Theses and Dissertations

This study is a contradistinction to research which assesses the effects of exercise only on older adults who are in good health. This study examined the effect of an eight-week exercise program on 24 individuals with mental impairments, primarily Alzheimer's disease and dementia. Subjects were volunteers who resided in a long-term care skilled nursing facility (SNF). Group composition was 7 males, mean age 83.29 and 17 females, mean age 88.71; mental and physical function levels varied from supervised to total dependence of care. Six variables were tested: right and left shoulder flexibility, right and left hand grip strength, modified sit …

The Effect Of Acute Alcohol Intoxication On Memory Scan And Memory Span In Working Memory, Dawn M. Kugler

Theses and Dissertations

The efficiency of working memory processes has been studied by many researchers. Verbal ability and intoxication with ethanol are two hypothesized influences on the efficiency of working memory processes. This study looked at these factors across two measures, memory span tasks and memory scan tasks. This study also examined the extent to which verbal ability modulates the effect of alcohol on working memory performance.

Seventy-eight male subjects participated in the present study. Subjects who reported drinking at least two drinks on two separate occasions per week were invited to participate. Subjects were administered the WAIS-R Vocabulary subtest and categorized as …

Discrete Simulation Of Fractional Order Systems, Jeffrey A. Blank

Theses and Dissertations

Fractional calculus has been shown useful for describing many real world systems, and studies are currently underway to generalize control theory to incorporate fractional states. This investigation derives a method for simulating the time response of fractional order systems using a recursive difference equation. The technique used effectively approximates a simple fractional order integrator as a summation of integer order terms. The discrete transfer function is also derived and the frequency response of the discrete algorithm is compared to the exact continuous case. Using 20 or more retained past values in the difference equation, the discrete half-order integrator demonstrates a …

Tensile Strength Characterization Of A Metal Matrix Composite With Circular Holes, Jeffrey Rattray

Theses and Dissertations

Static tensile testing conducted at room temperature and 650 C shows notch sensitivity for a quasi-isotropic lay-up of a titanium alloy metal matrix composite. The specific material used was SCS-6/Beta 21S. Some unnotched specimens were tested and then the diameter-to-width ratio was varied from 0.1 to 0.4. The room temperature unnotched strength is 840 MPa, and the strength falls to less than half this value at 650 C. The off-axis plies of the (0, ±45, 90)_s lay-up exhibit debonding of the fibers from the matrix at only ten percent of failure stress. This debonding is shown with acetate replicas …

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 …

Plasma Transport In A Magnetic Multicusp Negative Hydrogen Ion Source, Ricky G. Jones

Theses and Dissertations

An analysis of plasma transport through the magnetic filter in tandem magnetic multicusp negative hydrogen ion sources was conducted to determine the mechanism of thermal electron diffusion, explain thermal electron cooling, describe the transport of primary electrons through the filter, and model positive ion species transport. The thermal electron flux was shown to exceed its classical value by one to three orders of magnitude. The flux variation with temperature was best described using a Coulomb-like temperature gradient drag term, consistent with diffusion due to ion-sound-like turbulence. Thermal electron energy flux loss was shown to be dominated by inelastic collisions at …

Crack Growth Rate Modeling Of A Titanium-Aluminide Alloy Under Thermal-Mechanical Cycling, John J. Pernot

Theses and Dissertations

In this study, a model is developed to predict crack growth rates in a titanium-aluminide alloy under thermal-mechanical fatigue (TMF). This TMF crack growth rate prediction model, which requires only isothermal data to define its parameters, is distinguished from earlier models in two ways. First, it accounts for mechanical-fatigue and environmental crack growth rate contributions while it also considers a retardation mechanism thought to be caused by creep blunting of the crack tip. This is the first study to account for such a retardation mechanism during TMF. The second uniqueness of the model is that its general form can account …

A Study To Improve The Brazilian Air Force's Material Management System, Nelson R. Farias, Pedro R. Boareto

Theses and Dissertations

The first objective of this study was to identify all the common supply items currently being managed separately in the inventory of the various types of aircraft employed by the Brazilian Air Force, and to show how the system could be reorganized to consider the compatibility among these items. DBASE III programs were used to examine a file with 30103 registers containing part numbers occurring more than once in different aircraft's inventory, and to classify them in groups of identical items likely to be centrally managed. In addition, it was demonstrated that the system's structure would support the proposed reorganization …