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New Algorithms For Moving-Bank Multiple Model Adaptive Estimation, Juan R. Vasquez
New Algorithms For Moving-Bank Multiple Model Adaptive Estimation, Juan R. Vasquez
Theses and Dissertations
The focus of this research is to provide methods for generating precise parameter estimates in the face of potentially significant parameter variations such as system component failures. The standard Multiple Model Adaptive Estimation (MMAE) algorithm uses a bank of Kalman filters, each based on a different model of the system. A new moving-bank MMAE algorithm is developed based on exploitation of the density data available from the MMAE. The methods used to exploit this information include various measures of the density data and a decision-making logic used to move, expand, and contract the MMAE bank of filters. Parameter discretization within …
Parallel Implementation Of An Artificial Neural Network Integrated Feature And Architecture Selection Algorithm, Craig W. Rizzo
Parallel Implementation Of An Artificial Neural Network Integrated Feature And Architecture Selection Algorithm, Craig W. Rizzo
Theses and Dissertations
The selection of salient features and an appropriate hidden layer architecture contributes significantly to the performance of a neural network. A number of metrics and methodologies exist for estimating these parameters. This research builds on recent efforts to integrate feature and architecture selection for the multilayer perceptron. In the first stage of work a current algorithm is developed in a parallel environment, significantly improving its efficiency and utility. In the second stage, improvements to the algorithm are proposed. With regards to feature selection, a common random number (CRN) addition is proposed. Two new methods of architecture selection are examined, to …
The Application Of Sequential Convex Programming To Large-Scale Structural Optimization Problems, Todd A. Sriver
The Application Of Sequential Convex Programming To Large-Scale Structural Optimization Problems, Todd A. Sriver
Theses and Dissertations
Structural design problems are often modeled using finite element methods. Such models are often characterized by constraint functions that are not explicitly defined in terms of the design variables. These functions are typically evaluated through numerical finite element analysis (FEA). Optimizing large-scale structural design models requires computationally expensive FEAs to obtain function and gradient values. An optimization approach which uses the SCP sequential convex programming algorithm of Zillober, integrated as the optimizer in the Automated Structural Optimization System (ASTROS), is tested. The traditional approach forms an explicitly defined approximate subproblem at each design iteration that is solved using the method …
Improved Mathematical Modeling For Gps Based Navigation, Salvatore Nardi
Improved Mathematical Modeling For Gps Based Navigation, Salvatore Nardi
Theses and Dissertations
This thesis is concerned with the development of new closed form GPS position determination algorithms that work in the presence of pseudorange measurement noise. The mathematical derivation of two closed form algorithms, based on stochastic modeling and estimation techniques, is presented. The algorithms provide an estimate of the GPS solution parameters (viz., the user position and the user clock bias) as well as the estimation error covariance. The experimental results are analyzed by comparison to the baseline results from the conventional Iterative Least Squares (ILS) algorithm. In typical GPS scenarios, the closed form algorithms are extremely sensitive to noise, making …
A Validation Study Of The Air Force Weather Agency (Afwa) Jetrax Contrail Forecast Algorithm, Jeffrey D. Shull
A Validation Study Of The Air Force Weather Agency (Afwa) Jetrax Contrail Forecast Algorithm, Jeffrey D. Shull
Theses and Dissertations
Accurate contrail forecasts allow pilots to avoid levels of the atmosphere which are conducive to contrail formation, reducing their likelihood of being visually detected by enemy forces. The primary objective of this thesis is to evaluate the performance of the JETRAX contrail forecast algorithm currently used by the Air Force Weather Agency to support military air operations. A total of 397 ground-based contrail observations were collected at Wright-Patterson Air Force Base on 27 different days. Observations were collected with the aid of air traffic control radar, which greatly facilitated the positive identification of overflying aircraft and provided necessary information such …
Modified Multiple Model Adaptive Estimation (M3Ae) For Simultaneous Parameter And State Estimation, Mikel M. Miller
Modified Multiple Model Adaptive Estimation (M3Ae) For Simultaneous Parameter And State Estimation, Mikel M. Miller
Theses and Dissertations
In many estimation problems, it is desired to estimate system states and parameters simultaneously. However, inherent to traditional estimation architectures of the past, the designer has had to make a trade-off decision between designs intended for accurate state estimation versus designs concerned with accurate parameter estimation. This research develops one solution to this trade-off decision by proposing a new architecture based on Kalman filtering (KF) and Multiple Model Adaptive Estimation (MMAE) techniques. This new architecture, the Modified-MMAE (M3AE), exploits the benefits of an MMAE designed for accurate parameter estimation, and yet performs at least as well in state …
Evaluation Of Satellite Microwave Derived Surface Temperature Algorithms For The Period August 1996 To February 1997, Charles H. Harris
Evaluation Of Satellite Microwave Derived Surface Temperature Algorithms For The Period August 1996 To February 1997, Charles H. Harris
Theses and Dissertations
The Air Force Weather Agency (AFWA) has two operational algorithms that derive surface temperatures from microwave observations taken by the Special Sensor Microwave Imager (SSM/I) which rides aboard space platforms of the Defense Meteorological Satellite Program (DMSP). The algorithm called Temperature from Satellite Microwave Imager (TS) is used to analyze global cloud coverage. The second algorithm is fittingly called Calibration and Validation (CV), as it was the algorithm used to calibrate and validate the first SSM/I in 1987. Multiple linear regression defined the algorithms from empirically gathered brightness temperatures and simultaneous surface temperatures. The key questions were how much data …
Embedding A Reactive Tabu Search Heuristic In Unmanned Aerial Vehicle Simulations, Joel L. Ryan
Embedding A Reactive Tabu Search Heuristic In Unmanned Aerial Vehicle Simulations, Joel L. Ryan
Theses and Dissertations
We apply a Reactive Tabu Search (RTS) heuristic within a discrete event simulation to solve routing problems for Unmanned Aerial Vehicles (UAVs). Our formulation represents this problem as a multiple Traveling Salesman Problem with time windows (mTSPTW), with the objective of attaining a specified level of target coverage using a minimum number of vehicles. Incorporating weather and probability of UAV survival at each target as random inputs, the RTS heuristic in the simulation searches for the best solution in each realization of the problem scenario in order to identify those routes that are robust to variations in weather, threat, or …
Azimuth And Range Optimization Of The Velocity Azimuth Display (Vad) Algorithm In The Wsr-88d, David L. Craft
Azimuth And Range Optimization Of The Velocity Azimuth Display (Vad) Algorithm In The Wsr-88d, David L. Craft
Theses and Dissertations
The Velocity Azimuth Display (VAD) algorithm occasionally produces inaccurate wind estimates for the VAD Wind Profile (VWP) product of the Weather Surveillance Radar 1988 Doppler (WSR-88D) System. Weather forecasters have observed differences between the radar's wind profiles and wind profiles produced by rawinsondes and vertical wind profilers, when radiation and subsidence inversions in the atmosphere caused the radar beam to super refract. This thesis sought to improve the operational use of the VWP product for the WSR-88D near Denver, CO, by finding the optimal VAD algorithm Azimuth and Range parameter settings to overcome data contamination by hills located at the …
Improving Algorithmic Efficiency Of Aircraft Engine Design For Optimal Mission Performance, Paul T. Millhouse
Improving Algorithmic Efficiency Of Aircraft Engine Design For Optimal Mission Performance, Paul T. Millhouse
Theses and Dissertations
Automated techniques for selecting jet engines that minimize overall fuel consumption for a given aircraft mission have recently been developed. However, the current techniques lack the efficiency required by Wright Laboratories. Two noted dependencies between turbine engine fan pressure ratio, bypass ratio, high pressure compressor pressure ratio and overall engine mass flow allows for a reduction in the number of independent design variables searched in the optimization process. Additionally, through the use of spatial statistics (specifically kriging estimation), it is possible to significantly reduce the number of time consuming response function evaluations required to obtain an optimal combination of engine …
Analyzing Horizontal Distances Between Wsr-88d Thunderstorm Centroids And Cloud-To-Ground Lightning Strikes, Steve L. Renner
Analyzing Horizontal Distances Between Wsr-88d Thunderstorm Centroids And Cloud-To-Ground Lightning Strikes, Steve L. Renner
Theses and Dissertations
On April 29, 1996, lightning struck the airfield at Hurlburt Field, FL, killing one Airmen and injuring ten others. This cloud to ground lightning strike hit eight minutes after a lightning advisory was canceled. At the time of the strike, thunderstorms were observed 7 to 10 miles north and south of the airfield. The incident raised questions about Air Force Weather Agency's lightning criteria. Soon after the incident, a Lightning Safety Review Panel was assembled to determine the adequacy of lightning advisories. One of the questions posed to the panel was could an incident like Hurlburt happen again? The review …
Concept Vectors: A Synthesis Of Concept Mapping And Matrices For Knowledge Representation In Intelligent Tutoring Systems, Mark L. Dyson
Concept Vectors: A Synthesis Of Concept Mapping And Matrices For Knowledge Representation In Intelligent Tutoring Systems, Mark L. Dyson
Theses and Dissertations
A review of the literature relating to intelligent tutoring systems (ITS) reveals that the bulk of research to date is focused on the student, and on methods for representing the knowledge itself. From student models to learning schemas to presentation methods, comparatively little attention has been paid to the problem of educators attempting to build viable lesson plans for use in an ITS environment--yet when this problem is addressed in the literature, it is recognized as a potentially daunting one. This thesis addresses the problem of ITS lesson plan development by proposing a practical, computable approach for knowledge engineering that …
Applications Of Unsupervised Clustering Algorithms To Aircraft Identification Using High Range Resolution Radar, Dzung Tri Pham
Applications Of Unsupervised Clustering Algorithms To Aircraft Identification Using High Range Resolution Radar, Dzung Tri Pham
Theses and Dissertations
Identification of aircraft from high range resolution (HRR) radar range profiles requires a database of information capturing the variability of the individual range profiles as a function of viewing aspect. This database can be a collection of individual signatures or a collection of average signatures distributed over the region of viewing aspect of interest. An efficient database is one which captures the intrinsic variability of the HRR signatures without either excessive redundancy typical of single-signature databases, or without the loss of information common when averaging arbitrary groups of signatures. The identification of 'natural' clustering of similar HRR signatures provides a …
Atmospheric Induced Errors In Space-Time Adaptive Processing, Vinod D. Naga
Atmospheric Induced Errors In Space-Time Adaptive Processing, Vinod D. Naga
Theses and Dissertations
This thesis examines the effects of atmospheric turbulence-induced phase perturbations on the performance of ground-based Space-Time Adaptive Processing (STAP) systems. Both Fully Adaptive Joint Domain Optimum and Partially Adaptive Factored-Time Space processing methods are examined. This thesis concentrates on the turbulence effects on STAP applied to ground-based arrays. This thesis further focuses on the capability of STAP to resolve targets at low elevation angles in the presence of turbulence. Only clutter interference and receiver noise are considered. Turbulence effects on the EM phase-front are calculated for turbulence strength Cn(2) values ranging from 5.0 x 10(exp -14) m-2/3 to 5.0 x …
A Reconfigurable Superscalar Architecture, Christopher B. Mayer
A Reconfigurable Superscalar Architecture, Christopher B. Mayer
Theses and Dissertations
The invention of the Field Programmable Gate Array (FPGA) has led to a number of interesting developments. One is the idea of providing custom hardware support for applications running on a computer. These reconfigurable computers have been shown to decrease the execution time for some applications. Based on past results, attention has subsequently turned to using reconfigurable computing in general-purpose computers (e.g. desktop and workstation environments). This thesis develops a design for just such a computer. The design, FPGADLX, is based on a hypothetical superscalar computer running the DLX instruction set and is generic enough in principle to be adapted …
A Single Chip Low Power Implementation Of An Asynchronous Fft Algorithm For Space Applications, Bruce W. Hunt
A Single Chip Low Power Implementation Of An Asynchronous Fft Algorithm For Space Applications, Bruce W. Hunt
Theses and Dissertations
A fully asynchronous fixed point FFT processor is introduced for low power space applications. The architecture is based on an algorithm developed by Suter and Stevens specifically for a low power implementation. The novelty of this architecture lies in its high localization of components and pipelining with no need to share a global memory. High throughput is attained using large numbers of small, local components working in parallel. A derivation of the algorithm from the discrete Fourier transform is presented followed by a discussion of circuit design parameters specifically, those relevant to space applications. The generic architecture is explained with …
A Mammographic Registration Method Based On Optical Flow And Multiresolution Computing, Kevin A. Lee
A Mammographic Registration Method Based On Optical Flow And Multiresolution Computing, Kevin A. Lee
Theses and Dissertations
Mammography is a potent weapon in the fight against Breast Cancer, due in large part to its widespread availability and low cost. Despite the fact that mammography can detect small lesions as early as two years before they become palpable on physical exam, between 10 and 30 percent of cancerous lesions go undetected during evaluation by the radiologist. One approach to improving detection rates involves comparing mammograms of the same breast from successive years. Since most forms of breast cancer develop slowly, multiple view techniques might be able to detect subtle changes indicative of cancerous growth. This thesis proposes a …
Atmospheric Turbulence Scintillation Effects On Wavefront Tilt Estimation, James A. Louthain
Atmospheric Turbulence Scintillation Effects On Wavefront Tilt Estimation, James A. Louthain
Theses and Dissertations
A new atmospheric turbulence screen generator is developed for use in performance calculations of adaptive optics systems valid over a wide range of atmospheric turbulence parameters. The screen generator accounts for diffraction effects caused by weak turbulence and incorporates the phase, amplitude, and cross statistics of the perturbed optical field. The wavefront's phase and amplitude perturbations are taken from the correlation functions developed by Lee and Harp and the cross correlation of the phase and amplitude derived in this thesis. The screen generator uses a modal representation to perform a Fourier series expansion of the wavefront phase and amplitude over …
Displacement Of The Earth's Bow Shock And Magnetopause Due To An Impinging Interplanetary Shock Wave, William A. Olson
Displacement Of The Earth's Bow Shock And Magnetopause Due To An Impinging Interplanetary Shock Wave, William A. Olson
Theses and Dissertations
Interplanetary shock waves (ISWs) propagating through the solar wind can collide with the earth's bow shock, resulting in a series of new shocks, contact discontinuities, and rarefaction waves which interact to effectively move the bow shock and magnetopause toward the earth. A one dimensional MacCormack predictor corrector algorithm with Flux Corrected Transport (FCT) was developed to model the ISW bow shock and magnetopause interactions, and to numerically predict their propagation speeds after collision. Analytic relationships for the Mach numbers and propagation speeds of the generated shock waves and contact discontinuities were used to validate the model and to compare numerical …
Analytic Transfer Function Of The Forward Propagation Of Diffuse Photon Density Waves In Turbid Media With An Embedded Spherical Inhomogeneity, Deborah L. Lasocki
Analytic Transfer Function Of The Forward Propagation Of Diffuse Photon Density Waves In Turbid Media With An Embedded Spherical Inhomogeneity, Deborah L. Lasocki
Theses and Dissertations
Diffusing photons can be used to detect and localize optical inhomogeneities embedded in turbid media such as clouds, fog, paint and human tissue. This thesis shows that a transfer function derived from an analytic solution of the Helmholtz equation can completely characterize in three dimensions the perturbations in the forward propagation phenomena caused by a spherical defect object in a multiple-scattering medium. Two models of the forward propagation behavior of diffuse photon density waves in homogeneous, infinite, turbid media that contains a spherical inhomogeneity are examined. The first model is an exact analytic solution based on a modal expansion in …
Modeling And Simulation Support For Parallel Algorithms In A High-Speed Network, Dustin E. Yates
Modeling And Simulation Support For Parallel Algorithms In A High-Speed Network, Dustin E. Yates
Theses and Dissertations
This thesis investigates the ability of a simulation model to compare and contrast parallel processing algorithms in a high-speed network. The model extends existing modeling, analysis, and comparison of parallel algorithms by providing graphics based components that facilitate the measurement of system resources. Simulation components are based on the Myrinet local area network standard. The models provide seven different topologies to contrast the performance of five variations of Fast Fourier Transform (FFT) algorithms. Furthermore, the models were implemented using a commercially developed product that facilitates the testing of additional topologies and the investigation of hardware variations. Accurate comparisons are statistically …
A Wire Antenna Designed For Space Wave Radiation Over The Earth Using A Genetic Algorithm, Brian S. Sandlin
A Wire Antenna Designed For Space Wave Radiation Over The Earth Using A Genetic Algorithm, Brian S. Sandlin
Theses and Dissertations
A wire antenna is designed for optimal performance at low elevation angles in the presence of a lossy half-space. A simple genetic algorithm (GA) and GENOCOP III software are each integrated with Numerical Electromagnetics Code Version 4.1 (NEC4.1) to optimize a wire antenna geometry for multiple objectives: power gain, azimuthal symmetry, and input impedance. The performance of the two versions of the integrated GA are compared. Several of the resulting antennas are analyzed, and an antenna is proposed for use in a Remote Intrusion Monitoring System (RIMS). Simulations suggest that the proposed antenna, which is well-matched, offers a significant increase …
Fpga Processor Implementation For The Forward Kinematics Of The Umdh, Steven M. Parmley
Fpga Processor Implementation For The Forward Kinematics Of The Umdh, Steven M. Parmley
Theses and Dissertations
The focus of this research was on the implementation of a forward kinematic algorithm for the Utah MIT Dexterous Hand (UMDH). Specifically, the algorithm was synthesized from mathematical models onto a Field Programmable Gate Array (FPGA) processor. This approach is different from the classical, general purpose microprocessor design where all robotic controller functions including forward Kinematics are executed serially from a compiled programming language such as C. The compiled code and subsequent real time operating system must be stored on some form of nonvolatile memory, typically magnetic media such as a fixed or hard disk drive, along with other computer …
A Numerical Study Of High-Speed Missile Configurations Using A Block- Structured Parallel Algorithm, Douglas C. Blake
A Numerical Study Of High-Speed Missile Configurations Using A Block- Structured Parallel Algorithm, Douglas C. Blake
Theses and Dissertations
A numerical analysis of the aerodynamic phenomena associated with the high-speed flight of a sharp-nosed, four-finned, high-fineness ratio missile using a block-structured, parallel computer algorithm is presented. The algorithm, PANS-3EM, utilizes a second-order-accurate, shock-capturing, Total Variation Diminishing scheme and incorporates a Baldwin-Lomax turbulence model. PANS-3EM allows for extreme flexibility in the choice of computational domain decomposition and computing machine of implementation. Developmental work consists of conceptualization and verification of the algorithm as well as parallel performance and scalability studies conducted on a variety of computing platforms. Using PANS-3EM, the aerodynamic characteristics of the missile are investigated. Drag and pitching moment …