Engineering Commons^™

Computer Aided Design Of A Broadband Microwave Power Divider, Jaideep Mukherjee

Theses

The purpose of this thesis to provide alternative design procedure for a power divider that has broadband characteristics. The Wilkinson power divider consisting of cascaded quarter wave sections is known to increase the bandwidth while maintaining high isolation and good match conditions at individual ports. Resistors placed between the quarter wave sections served to increase isolation. The values of required components were determined using odd and even mode analysis. In this work, the approximate theory developed previously is used as a preliminary design model, and it is extended further by considering optimization techniques and coupling between adjacent arms. This novel …

Handling Of Glass Mat Thermoplastic From Manufacturing Station To Heating Station To Molding Machine, Ramulu Srinivas Neela

Theses

GMT composite sheets are a family of continuous glass fiber roving impregnated with thermoplastic resin with parts formed by compression molding. Significance of GMT sheets comes by its cost-effective performance sufficient to penetrate automotive, industrial, construction, and other markets not willing to pay for higher cost, fiber-reinforced composite systems. GMTs in comparison to traditional sheet metals and sheet molding compounds (SMCs) are lighter, corrosion resistant, require no special storage, exhibit faster cycle times, require no chemical reaction, produce less scrap, possess recycling benefits, are ready for painting, and exhibit maximum opportunities for parts consolidation due to exceptional strength, formability, lower …

Study Of A Non-Contact Gaging System Of Inspection, Gordhanbhai Ketan Patel

Theses

The quality control function has traditionally been performed using manual inspection methods and statistical sampling procedures. Manual inspection is generally a time - consuming procedure which involves precise, yet monotonous work. It often requires that parts be removed from the vicinity of the production machines to a separate inspection area. This causes delays and often constitutes a bottleneck in the manufacturing schedule.

As a solution to the above problem a Non - Contact Gaging System developed by Optical Gaging Products, Inc., has been used here to study the feasibility of using an automated inspection system and a procedure of developing …

Realization Of High-Speed Carry Propagation For Addition And Multiplication Using The Redundant Binary System On The Mesh And Hypercube Connected Structures, Anil Rana

Theses

The extensive development of large-scale digital computers has naturally been accompanied by a corresponding development of techniques for fast arithmetic operations. Addition is the basis for the majority of the other arithmetic operations and most of the required time is due to carry propagation delay. Various algorithms have been proposed for fast addition and multiplication. The algorithms proposed here use the redundant binary system and are designed for the mesh structure. The algorithms are very efficient for the addition and multiplication of long operands. The algorithms can also be implemented on the hypercube. The n-dimensional hypercube is a highly concurrent …

The Strength Of Cement Bentonite In Containment Structures, Liong Tin So

Theses

In recent years the use of cutoff or slurry walls has increased in the containment of hazardous waste. Several materials have been utilized for backfill in slurry walls. Two important properties of the material are shear strength and permeability. Previously, sodium bentonite had been used. However, it was discovered that variable pH would cause an increase in permeability. Studies have shown calcium bentonite have a constant permeability with varied pH (Oweis and Khera, 1990). This study was undertaken to determine strength of calcium bentonite as affected by cement and slag.

Triaxial shear tests and unconfined compression tests were done on …

A Graphic Editor And Real Time Simulator Of Petri Net, Tenian Tang

Theses

A structurally designed graphic editor and real time simulator of Petri nets (PN) is presented. The package is programmed by Turbo C language, which runs in IBM-PC environmental with graphics adaptor. Various kinds of PN systems such as ordinary, general and timed Petri net can be modeled and analyzed by firing the models with real time token movement animations. Some properties of analyzed PN such as reachability, deadlock, firing time can be studied. Several illustrative examples are presented. The possible further enhancements are also discussed.

Extension And Applications Of Knitting Technique For Petri Net Synthesis, Yanzhong Zhang

Theses

Petri nets have been used for modeling and analyzing various systems [1,2,3,4,8]. One approach to Petri net synthesis is a knitting technique [4,5, 6,7]. It was developed for modeling concurrent systems. The Petri net model is incrementally expanded by adding paths of nodes according to rules. To extend the knitting technique to cover synchronized systems, a set of new rules based on synchronic distance concept is presented. The rules penult synchronizing M exclusive processes (M 2) to a synchronic distance of any positive integer N. They can be applied to both exclusive processes and independent processes. The resulting Petri net …

A Color Petri Net Simulation Tool, Sanjaykumar V. Desai

Theses

A user friendly, modular and highly interactive graphical tool for drawing, editing and simulating color Petri nets is developed. The tool is designed to model concurrent and interlocked systems, such as flexible manufacturing systems, communication protocols and computer systems. A Color Petri Net(CPN) has a more concise graphical system representation than a standard Petri net, because net entities in CPN carry information. The CPNS(Color Petri Net Simulation) tool simulates a net having conflicts, reveals deadlocks, and creates a log file with the state history of the system yielding performance measures.

Development Of An Expert System For The Safety Of Workers From Electrical Hazards At Work Place, Faizul Islam

Theses

This thesis presents the development of an expert system for the safety of workers from electrical hazards at work place.

The objective of this work is to show how an expert system within the workplace can be used in helping to create an effective safety program.

An effective expert system for electrical safety have been developed for the workers to prevent accidents from electrical hazards using the safety regulations of Occupational Safety and Health Administration.

The regulations developed by OSHA have been incorporated in rule based expert system which can be accessed by any non computer professional and the system …

An Implementation Of Bionomial-Qmf For Subband Coding Of Speech, Feng Chen

Theses

A real-time subband speech codec is implemented by the author on TMS320C25 digital signal processor based hardware for speech compression down to 0.25 bit per sample.

The Binomial Quadrature Mirror Filters (B-QMFs) are employed as the basic block for the hierarchical, dynamic tree, analysis/synthesis filter bank. After the analysis, available bits are optimally allocated among subbands. Band statistics are updated to overcome the nonstationarities of speech signal.

The energy compaction performance of this codec is compared with different subband and DCT in simulations for speech signals and AR(1) source models.

It is shown that the speech codec implemented provides an …

Vision-Guided Servoing Robot Arm System, Shing Lee

Theses

This thesis investigate the problem of tracking 2-D circle parts with an eye-in-hand robot arm system. A vision module capable of measuring the motion of a circle is developed. Two algorithms based on the conic equation representation of circle and the symmetric property are developed. The first algorithm approximates the image of the circle as an ellipse. The second algorithm use the arc radius estimator to extract two image points of the circle located at the center of the largest arc. These image points are then used to solve for the inverse perspective transformation. An inverse kinematics solution based on …

Limits Of Limit Equilibrium And Finite Element Techniques Applied To Cracked Debris Dams On Collapsing Foundations, Stanley Soliday Jr.

Dissertations and Theses

Limits of slope stability, limit equilibrium methods, and of the finite element code FEADAM are reached in the application of these methods to the problem of cracked dams constructed on collapsing soils.

Utilizing a generic dam, various classic slope stability approaches are tested as possible dam slope failure mechanisms. Slope stability methods are rejected as a way to accurately define and quantify the collapse problem. As a result of this work a block rotation mode of collapse is postulated. Then the finite element method (FEM) is used to try to define and quantify the collapse problem. The FEM is applied …

Ignoring Interprocessor Communication During Scheduling, Chintamani M. Patwardhan

Dissertations and Theses

The goal of parallel processing is to achieve high speed computing by partitioning a program into concurrent parts, assigning them in an efficient way to the available processors, scheduling the program and then executing the concurrent parts simultaneously. In the past researchers have combined the allocation of tasks in a program and scheduling of those tasks into one operation. We define scheduling as a process of efficiently assigning priorities to the already allocated tasks in a program. Assignment of priorities is important in cases when more than one task at a processor is ready for execution. Most heuristics for scheduling …

A Multiple Coupled Microstrip Transmission Line Model For High-Speed Vlsi Interconnect Simulation, Lawrence Stevan Uzelac

Dissertations and Theses

A model is presented which incorporates the advantages of a mixed mode simulation to characterize transmission line behavior in multiple coupled Transmission line systems. The model is intended for use by digital circuit designers who wish to be able to obtain accurate transmission line behavior for complex digital systems for which continuous time simulation tools such as SPICE would be time prohibitive.

The model uses a transverse electromagnetic wave approximation to obtain solutions to the basic transmission line equations. A modal analysis technique is used to solve for the attenuation and propagation constants for the transmission lines. Modal analysis done …

Spectral And Spatial Quantum Efficiency Of Algaas/Gaas And Ingaas/Inp Pin Photodiodes, Steven Alan Tabor

Dissertations and Theses

This thesis reports a novel system capable of testing both the spectral responsivity and the spatial quantum efficiency uniformity of heterostructure photodiodes using optical fiber coupled radiation. Testing was performed to confirm device specifications. This study undertakes to quantify the spectral bandwidth of an AlGaAs I GaAs double heterostructure photodiode and two InGaAs I InP double heterostructure PIN photodiodes at D.C., through the use of spatial scanning. The spatial scanning was done using lasers at 670 nm, 780 nm, 848 nm, 1300 nm, and 1550 nm, coupled through singlemode optical fiber. The AlGaAs I GaAs material system covers the 600 …

Computerized Aircraft Accident Investigation: Federal Aviation Administration Aviation Safety Inspectors' Perceptions, David S. Ryan

Master's Theses - Daytona Beach

The purpose of this study was to solicit the perceptions of Federal Aviation Administration (FAA) Aviation Safety Inspectors (ASIs) on the use of a personal computer in the aircraft accident investigation process. A descriptive study survey questionnaire was used to collect the data for the study, which was sent to 150 FAA ASIs. The data collected supported the hypothesis that aircraft accident investigators think the use of a computer will help them with accident report form completion, managing the accident data collected, and in determining the factors contributing to an accident. Furthermore, the data supported the hypothesis that the use …

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.

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 …

Software Cost Estimating Models: A Calibration, Validation, And Comparison, Gerald L. Ourada

Theses and Dissertations

This study was a calibration, validation and comparison of four software effort estimation models. The four models evaluated were REVIC, SASET, SEER, and COSTMODL. A historical database was obtained from Space Systems Division, in Los Angeles, and used as the input data. Two software environments were selected, one used to calibrate and validate the models outside their environment of calibration. REVIC and COSTMODL are COCOMO derivatives and were calibrated using Dr. Boehm's procedure. SASET and SEER were found to be un-calibratable for this effort. Accuracy of all the models was significantly low; none of the models performed better against the …

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

Theses and Dissertations

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

Investigation Of The Effects Of Increased Order Compensators In Mixed H2/H∞ Optimization, Scott R. Wells

Theses and Dissertations

The problem of minimizing the 2-norm of one transfer function subject to an infinity-norm bound on another transfer function is examined for increased order controllers. In particular, the theoretical results of the full order case are extended to the higher order case, and SISO and MIMO numerical examples are given for increasingly higher order compensators. Some of the key proofs for higher order compensators include: the global minimum 2-norm is unachievable under output feedback for certain levels of gamma regardless of compensator order; the solution to the mixed H2/H infinity problem lies on the boundary of the infinity-norm constraint for …

Design Of An Optimum Thrust Nozzle For A Typical Hypersonic Trajectory Through Computational Analysis, David J. Herring

Theses and Dissertations

An analysis of a planar supersonic nozzle for a NASP type vehicle was performed with a computer program that used the new upwind flux difference splitting (FDS) method. Thrust optimization, off-design performance, and cowl angle parametric analyses were accomplished, using FDS code, an oblique shock wave solver program, and a Scramjet cycle analysis code, at six points on a 1000 PSF maximum dynamic pressure trajectory, for the Mach numbers 7.5, 10.0, 12.5, 15.0, 17.5, and 20.0. Results from the single parameter number range from 7.5 to 20.0, the attachment angles identified as optimum for the respective trajectory points were 38.0, …

Computation Of Planar Store Trajectories Using An Adaptive Grid Procedure, William D. Hack

Theses and Dissertations

The objective of this research was to compare a quasi-analytical, potential flow/three-degree-of-freedom model to an implicit-Euler algorithm for the calculation of store trajectories. The implicity algorithm uses a cell- centered, finite-volume, spatial discretization applied to the Euler equations, written in time-dependent, curvilinear-coordinates. A flux-differencing Roe scheme is employed to find the split-fluxes and the Steger/Warming flux-vector method is used to calculate the flux-Jacobians. The potential flow and implicit- Euler algorithm are combined with a three-degree-of-freedom algorithm to evaluate the planar, freefall trajectories of a simple store shape. The research uses two different grid-modification techniques in the implicit algorithm evaluation. Data …

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 …

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 …

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 …

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 …