Engineering Commons^™

An Investigation Of The Floor Attachment Assembly Of A Large Transport Aircraft Seat Subjected To Crash Dynamic Loadings, Mark William Creager

Master's Theses - Daytona Beach

Accident investigations by the National Transportation Safety Board concluded that the passenger seat and restraint systems found in today's aircraft used by the airlines are inadequate to protect the occupant in airplane crashes. Computer models were developed of the seat-track assembly and finite element analyses were performed subjected to crash dynamic loadings. The seat-track interface was modeled with gap elements to accurately model the geometric interaction between the track and seat-track fittings. Results showed large deformations and stresses above yielding in both the seat and track when subjected to accelerations prescribed for certification under the Federal Aviation Administration (FAA) regulations.

Equipment Acquisition Lcc Approach, B S Chetty, K N Krishnaswamy

IIMB Management Review

The Life Cycle Costing (LCC) approach focuses attention on all funds to be expended during the useful life of a productive asset including associated activities directly linked to its use. LCC improves upon the procedure/evaluation criterion which is today totally biased towards short-term approach such as considering only first cost or price alone. The obvious benefits of the approach are discussed in detail in this paper for adaptation by organisations. However, the need for approriate data for applying this approach is also emphasised.

Resource Integration Using A Large Knowledge Base In Carnot, Christine Collet, Michael N. Huhns, Wei-Min Shen

Faculty Publications

A method for integrating separately developed information resources that overcomes incompatibilities in syntax and semantics and permits the resources to be accessed and modified coherently is described. The method provides logical connectivity among the information resources via a semantic service layer that automates the maintenance of data integrity and provides an approximation of global data integration across systems. This layer is a fundamental part of the Carnot architecture, which provides tools for interoperability across global enterprises.

Structural, Depositional, And Diagenetic Controls On Reservoir Development: St. Peter Sandstone, Newaygo County, Michigan, Mark S. Caldwell

Masters Theses

Enhanced reservoir quality in the Middle Ordovician St. Peter Sandstone is observed in gas bearing zones in wells located on domal structures. Geometry and degree of this enhanced porosity development is the result of the interplay of structural, depositional, and diagenetic controls. An integrated subsurface study of the Woodville/Goodwell field area was performed in order to document controls on hydrocarbon accumulation.

Recurrent structural growth of domal features throughout the Paleozoic is well documented by isopach mapping. Burial and thermal history studies indicate that hydrocarbons were generated in Ordovician aged source rocks during late Devonian to early Mississippian time, and accumulated …

An Experimental Investigation Of Bevelled Blade Coating For Paper, Mustafa Naci Altug

Masters Theses

In this study the total dynamic force (TDF) acting on the blade was determined at three different web speeds. The objective was to compare quantitatively the experimental results with the predictions of existing models to show whether or not any of these models predict coat weight development. The existing models include the lubrication theory, impact model, lateral force, and combinations of these models.

Under the conditions investigated, the estimated TDF was in good agreement only with the impact force (sum of impulse and hydrodynamic forces) model of blade coating. The impulse force accounted for 94% of the TDF and, therefore, …

Speech Recognition Using Multiple Features And Multiple Recognizers, Thomas F. Rathbun

Theses and Dissertations

The purpose of this thesis is to demonstrate the feasibility of using multiple features and multiple recognizers to perform isolated word recognition. This is accomplished by performing multiple independent recognition tests and fusing the results together to get a single recognition result. The speech data is recorded and each word is extracted into a separate file. Eight features are calculated for each word. The features are calculated on 512 sample time slices and produce 16 component vector output. The three recognizers use the eight features to produce a total of 24 error distance lists. These lists are then fused together …

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 …

Application Of Nonlinear Qft To Flight Control Design For High Angle Of Attack Maneuvers With Thrust Vectoring, Steven J. Rasmussen

Theses and Dissertations

Nonlinear Quantitative Feedback Theory (QFT) is applied to the design of an flight Control system (FCS) to control maneuvers of an agile aircraft. To do this, maneuvers are chosen that are desirable during within visual range combat. Plant transfer functions are developed through the use of system identification, using the input/output time histories of the maneuvers. During the system identification process the q sub ij(o) are found directly and are constrained to be minimum phase. After identifying the plants, the cascaded multiple-input multiple-output QFT technique is used to design the FCS. During the design of the FCS, stability boundaries are …

Electrically Erasable Programmable Integrated Circuits For Replacement Of Obsolete Ttl Logic, Joseph V. Breen

Theses and Dissertations

Two microcircuits with electrically erasable programmable logic arrays, which use Fowler-Nordheim (F-N) tunneling for both programming and erasing, were designed to demonstrate the use of programmable logic for obsolete TTL logic replacement. Each microcircuit was fabricated in the Orbit 2-micron double-poly low noise analog CMOS process through MOSIS. Software to generate VHDL structural models from a pin list was developed and the logic of both designs was verified by simulation using the Zycad VHDL simulator. The first microcircuit included a simple programmable logic circuit and test cells that allowed measurement of the programming characteristics of the floating gate transistors. Test …

A Rigorous Utd Analysis Of Electromagnetic Scattering From Resistive Strips And Resistive-Loaded Conducting Strips, Douglas H. Casanova

Theses and Dissertations

This thesis investigates electromagnetic scattering from resistive strips and resistive-loaded conducting strips using a rigorous UTD formulation. The UTD diffraction coefficients are based on the Wiener-Hopf technique and Jones' method. Scattering predictions are performed for constant resistive strips, constant resistive-loaded conducting strips, tapered resistive strips, and tapered resistive-loaded conducting strips. All strip geometries have a total width of 4 lambda. Predictions are compared to method of moments (MM) and measurements to determine the validity of the UTD prediction. Overall, there is good agreement. For TMz polarization the only deviations that occur with MM are near edge-on when the degree of …

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 …

Radar Scattering From Foamed Plastic Target Supports, Michael W. Chambers

Theses and Dissertations

This study investigates the scattering from foamed ranges to support all sizes of targets for radar cross section measurements. Two common foamed plastics, styrofoam and expanded bead polystyrene (EPS), are discussed. Two types of scattering are associated with foamed plastic, coherent and incoherent. The incoherent is normally the lowest, but has not been satisfactorily quantified. Coherent scattering is related to the shape of the target, and the emphasis of this study is on the coherent return. One goal was to predict the coherent RCS of an EPS column using the Uniform Theory of Diffraction (UTD). It was found that UTD …

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 …

Application Of Silicon Micromachining To Thermal Dissipation Issues In Wafer Scale Integrated Circuits, Edward Cosnyka

Theses and Dissertations

The purpose of this research effort was to investigate the feasibility of applying the silicon micromachining technique to thermal management as applied to integrated circuits and wafer scale integration techniques. Three silicon micromachined structures and an untextured reference wafer were compared as heat-dissipating surfaces. These four surfaces were realized using 3-inch diameter, single crystal silicon wafers. The following structures were micromachined in silicon wafers using wet chemical, anisotropic etching and photolithographic techniques: (1) randomly spaced and sized pyramids in (100)-oriented silicon, (2) deep vertical-wall grooves in (110)-oriented silicon, and (3) micro-fluid channels in (100)-oriented silicon. The heat- dissipating silicon wafers …

Binaural Sound Localization Using Neural Networks, Rushby C. Craig

Theses and Dissertations

The purpose of this study was to investigate the use of Artificial Neural Networks to localize sound sources from simulated, human binaural signals. Only sound sources originating from a circle on the horizontal plane were considered. Experiments were performed to examine the ability of the networks to localize using three-different feature sets. The feature sets used were: time-samples of the signals, mena Fast Fourier Transform magnitude and cross correlation data, and auto-correlation and cross correlation data. The two different types of sound source signals considered were tones and gaussian noise. The feature set which yielded the best results in terms …

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 …

Robotic Tactile Sensors Fabricated From A Monolithic Silicon Integrated Circuit And A Piezoelectric Polyvinylidene Fluoride Thin Film, Craig S. Dyson

Theses and Dissertations

The purpose of this research effort was to design, fabricate, and test a tactile sensor system consisting of an external high impedance switch circuit, an external multiplexing circuit, and a tactile sensor IC. In order to accomplish this objective, a hardware design and selection process was implemented along with a logical test methodology. An external multiplexer circuit samples all of the array elements in 50 ms. The current prototype sensor has linearity spanning loads of 0.8 g to 135 g, a load resolution of 20 g, and a maximum bandwidth of 25 Hz. Using an elementary shape recognition algorithm the …

A Rigorous Uniform Diffraction Analysis Of The Electromagnetic Scattering From Impedance Edges And Junctions, Joseph C. Fortney

Theses and Dissertations

This paper investigates the scattering from impedance strips and impedance-loaded conducting strips. The impedance strips are analyzed using Senior's impedance half plane formulation. Once the primary diffraction from the impedance half plane is presented, it is used to develop multiple diffraction mechanisms on an impedance strip. The scattering from impedance-loaded strips are analyzed using Maliuzhinets' impedance wedge formulation. The primary diffraction mechanism from an impedance wedge is used to develop the multiple diffractions on an impedance double wedge. The multiple diffractions on both types of strips are developed using the Extended Spectral Ray Method. Sample calculations are made for impedance …

Gabor Segmentation Of High Resolution Synthetic Aperture Radar Imagery, Michael A. Hazlett

Theses and Dissertations

This thesis investigates the use of Gabor filters and a radial basis function (RBF) network for segmentation of high resolution (1 foot by 1 foot) synthetic aperture radar (SAR) imagery. Processing involved correlation between the SAR imagery and Gabor functions. Two methods for selecting the optimal Gabor filters are presented. This research used complex Gabor functions and operated on single polarization HH complex data. Following the selection f the proper Gabor filters, correlation coefficients for each image were calculated and used as features for the RBF network. Provided are results demonstrating how Gabor processing and a RBF network provide image …

Determination Of Bistatic Radar Clutter Power From Topographic Data, Clyde R. Heddings

Theses and Dissertations

The purpose of this research was to develop a procedure for estimating the average bistatic radar clutter power from a topographic map using rough surface scattering theory. First, the terrain in the radar target area was divided into sub regions having homogeneous characteristics. A joint Gaussian distribution for the surface heights was fitted from the information contained in the topographic map contour lines for each homogeneous area. From these distributions, the normalized radar cross section for each terrain area was determined. The clutter power for each range cell was then determined via a modified radar range equation. The procedure was …

Kalman Filter Tracking Of A Reflective Target Using Forward Looking Infrared And Doppler Return Measurements, Theodore D. Herrera

Theses and Dissertations

Plume phenomenology experiments conducted in 1990 uncovered the existence of plume speckle reflectance emanating from the exhaust of a solid- propellant rocket motor due to the presence of metallic particulates in the plume. This impeded attempts, that are dependent upon the speckle return of an actively illuminated target hardbody, to discern the plume/hardbody interface. This thesis investigates the feasibility of employing the Doppler return phenomenon in discerning the plume/hardbody interface and locating the hardbody center-of-mass. The potential of the Doppler phenomenon's utilization lies in the fact that the Doppler return frequency spectra of the plume and the hardbody respectively possess …

Characterizing The Sensitivity, Selectivity, And Reversibility Of The Metal-Doped Phthalocyanine Thin-Films Used With The Interdigitated Gate Electrode Field-Effect Transistor (Igefet) To Detect Organophosphorous Compounds And Nitrogen Dioxide, Clayton P. Howe

Theses and Dissertations

This study investigated the sensitivity, reversibility, and selectivity of the thin film coatings used on the interdigitated gate electrode field effect transistor (IGEFET) gas microsensor. These responses were quantified based on the dc resistance changes and frequency domain responses of the microsensor. The thin-film materials included: copper phthalocyanine (CuPc), nickel phthalocyanine (NiPc), and cobalt phthalocyanine (CoPc). The challenge gases included: diisopropyl methylphosphonate (DIMP), dimethyl methylphosphonate (DMMP), nitrogen dioxide, ammonia, and boron trifluoride. Tests of the CuPc thin-films and nitrogen dioxide challenges established the primary set of test parameters expected to maximize the selectivity, sensitivity, and reversibility of the thin-film coatings. …

A Robust Digital Flight Control System For An Unmanned Research Vehicle Using Discrete Quantitative Feedback Theory, Donald J. Lacey Jr.

Theses and Dissertations

This thesis describes application of digital multiple-input multiple- output (MIMO) Quantitative Feedback Theory (QFT) technique to the design of a three axis rate controller for the Lambda Unmanned Research Vehicle. The resulting robust controller performs well throughout the flight envelope without gain scheduling. It results from research done at the Air Force Institute of Technology. The Lambda URV was designed by the Control Systems Development Branch of the Wright Laboratory at Wright-Patterson AFB, OH for flight testing aircraft control hardware and software. The flight control system is built using a small perturbation linear model developed from flight test data. The …

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 …

Analysis Of Visual Illusions Using Multiresolution Wavelet Decomposition Based Models, John S. Laing

Theses and Dissertations

This thesis provides alternatives to the explanation that spatial filtering is responsible for the perception of illusory contours in the Kanisza Triangle illusion. Specifically, we use a Multiresolution Wavelet Decomposition to divide an image into spatial-frequency bands that are used as inputs to three biologically motivated models. The thesis includes a brief tutorial of Wavelet theory and an in-depth explanation of our implementation of recently published algorithms for Multiresolution Wavelet Analysis. The first model is based on the saccadic movements of the human eye. It demonstrates the importance of the high spatial-frequency content of an image in the formulation of …

Development Of High Angle Of Attack Control Laws For An Unstable, Non- Minimum Phase Aircraft Using Variations Of The Quantitative Feedback Technique, Mark A. Mcclure

Theses and Dissertations

This thesis discusses the application of variations of the quantitative feedback technique to a control problem with unstable, non-minimum phase plants. The X-29A research aircraft is used as the basis for developing a set of representative linearized aircraft dynamics models, which are modified to allow for the use of differential canard control inputs for enhanced maneuverability at extreme angles of attack. A specialized design approach is presented to develop frequency dependent weighting matrices, and the shortcomings of traditional methods are discussed. Four independent longitudinal compensators are developed by first designing loop transmission functions. Discussion is provided that addresses the limitations …

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 …

Design And Testing Of A Lightweight, Planar Microwave Lens, Paul M. Proudfoot

Theses and Dissertations

This thesis documents the design, fabrication, and testing of a lightweight, planar microwave lens. The lens consists of two planar arrays of lightweight printed circuit antennas interconnected by microstrip lines whose length varies as a function of position on the lens. Microwave energy is coupled from one face of the lens to the other by means of a slot etched in the ground plane. At 8.0 GHz the lens is ten wavelengths across, is less than 1/8 inch thick, and weighs less than 4 pounds. The lens can scan a beam over a ± 30 degree region in both the …

Design Of A Fiber Optic Image Transmission Link, Justin D. Redd

Theses and Dissertations

An original design is presented for a fiber optic based digital image transmission link operating at a serial bit rate of 250 Mbits/Second. The link is designed as an integral part of an airborne infrared imaging system with particular emphasis on avoiding problems associated with aircraft electromagnetic interference (EMI). Unique features include simplicity (single PC board transmitter and receiver), low power, low cost (under $3,000), and use of the latest off-the-shelf components (including the Gazelle GA9011/GA9012 HOT ROD chip set). Theoretical modeling is used to predict a bit error rate of better than 10^-15, while actual measurements include …