Engineering Commons^™

Vegetation Studies Of The Amazon Basin Using Enhanced Resolution Seasat Scatterometer Data, David G. Long, Perry J. Hardin, Peter T. Whiting

Faculty Publications

The Seasat-A scatterometer (SASS) was designed to measure the near-surface wind field over the ocean by inferring the wind from measurements of the surface radar backscatter. While backscatter measurements were also made over land, they have been primarily used for the calibration of the instrument. This has been due in part to the low resolution of the scatterometer measurements (nominally 50 km). In a separate paper the present authors introduced a new method for generating enhanced resolution radar measurements of the Earth's surface using spaceborne scatterometry. In the present paper, the method is used with SASS data to study vegetation …

Rank Conditioned Rank Selection Filters For Signal Restoration, Russell C. Hardie, Kenneth E. Barner

Electrical and Computer Engineering Faculty Publications

A class of nonlinear filters called rank conditioned rank selection (RCRS) filters is developed and analyzed in this paper. The RCRS filters are developed within the general framework of rank selection(RS) filters, which are filters constrained to output an order statistic from the observation set. Many previously proposed rank order based filters can be formulated as RS filters. The only difference between such filters is in the information used in deciding which order statistic to output. The information used by RCRS filters is the ranks of selected input samples, hence the name rank conditioned rank selection filters. The number of …

Cost Estimating And Forecasting For Highway Work In Kentucky, James D. Stevens

Kentucky Transportation Center Research Report

There is a need for a better cost estimating and forecasting for highway work in the Commonwealth of Kentucky. KRS45.245 grants the Interim Joint Committee on Transportation oversight of the biennial highway plan, including a review of all authorized highway project phases that exceed their estimates by 15%. In recent years, the Kentucky Transportation Cabinet has suffered the loss of many resources necessary to produce good cost estimated.

Estimates developed using current methods are not sufficiently accurate to preclude cost overruns in excess of 15%. During the biennium 134 overruns, totaling over $69 million, have been submitted to the Committee. …

Feasibility Analysis For Predicting A Kinetic Kill Zone For Aircraft Homing Missile Defense, Mark E. Ennis

Theses and Dissertations

An extended Kalman filter is used to predict a kinetic kill zone for use in aircraft self defense versus homing missiles. The analysis is limited to an in-the-plane analysis and focuses on finding the model parameters which have the largest impact on the predicted kill zone. No attempt is made to optimize the design of the filter model itself. The analysis computes the kill zone relative to an assumed aircraft trajectory using strictly filter computed statistics. No Monte-Carlo simulations are used throughout the thesis. The filter assumed to be on the evading aircraft, uses an onboard laser radar (ladar) to …

Clustering Techniques In Speaker Recognition, Douglas N. Prescott

Theses and Dissertations

This thesis presents a comparison based on identification rate, of three clustering techniques applied to cepstral features for speaker identification. LBG vector quantization as developed by Linde, Buzo and Gray; is used to provide benchmark performance for comparison with Fuzzy clustering (based on the unsupervised fuzzy partition-optimal number of classes, UFP-ONC algorithm by Gath and Geva) and an Artificial Neural Network, the Multilayer Perceptron. Cepstral features from the TIMIT, King and AFIT93 corpus speaker databases are used to produce speaker-identification classifiers using each of the clustering algorithms. The experiment reported evaluates the speaker identification performance using the 20-dimensional cepstral features …

Application Of Sequential Quadratic Programming To Large-Scale Structural Design Problems, Mark A. Abramson

Theses and Dissertations

Large-scale structural optimization problems are often difficult to solve with reasonable efficiency and accuracy. Such problems are often characterized by constraint functions which are not explicitly defined. Constraint and gradient functions are usually expensive to evaluate. An optimization approach which uses the NLPQL sequential quadratic programming algorithm of Schittkowski, integrated with the Automated Structural Optimization System ASTROS is tested. The traditional solution approach involves the formulation and solution of an explicitly defined approximate problem during each iteration. This approach is replaced by a simpler approach in which the approximate problem is eliminated. In the simpler approach, each finite element analysis …

A Simulation Approach To Granite Sentry System Analysis, Marilyn J. Bauer

Theses and Dissertations

This study demonstrated the use of simulation modelling to analyze Granite Sentry system performance. The availability simulation model constructed provides a number of system performance measures as a function of component MTBFs and MTTRs. Analysis of failure data prior to model construction supported the generally accepted use of exponentially distributed failure rates and lognormally distributed repair times.

A Heuristic Approach To Determining Cargo Flow And Scheduling For Air Mobility Command's Channel Cargo System, John Fitzsimmons Jr., John Walker

Theses and Dissertations

This research investigated a heuristic approach to schedule aircraft for the channel cargo system of the Unit States Air Forces Air Mobility Command AMC. Given cargo frequency of visit requirements, a fleet of aircraft, and possible routes, the objective of this research was to develop, implement, and test an iterative procedure to efficiently schedule and load aircraft in order to maximize the flow of cargo through the channel cargo system. Once a level of flow was established, attempts were made to minimize cost in terms of cumulative weighted time-in-system CWTIS. A minimum cost flow heuristic, incorporating a successive shortest path …

A Mean Value Analysis Heuristic For Analysis Of Aircraft Sortie Generation, Richard C. Jenkins

Theses and Dissertations

The primary objective of this study was to develop an analytical methodology based on the Mean Value Analysis algorithm that approximates the performance characteristics of a queueing network model QNM containing a fork- join queue with probabilistic branching. These performance characteristics are response time, throughput and queue length at each station. The QNM solved contains the essential features of the aircraft sortie generation process. The sensitivity of the methods accuracy to increases in server utilization was determined. The comparisons of the results of the MVA heuristic to the outputs of the Logistics Composite Model LCOM simulation indicate that the heuristics …

A Genetic Algorithm Approach To Automating Satellite Range Scheduling, Donald A. Parish

Theses and Dissertations

Satellite range scheduling involves scheduling satellite supports in which a satellite and a specific remote tracking station communicate with each other within a specified time window. As the number of satellite supports continue to increase, more pressure is placed on the current manual system to generate schedules efficiently. Previous research efforts focused on heuristic and mixed-integer programming approaches which may not produce the best results. The objective of this research was to determine if a genetic algorithm approach to automating the generation of 24 hour schedules was competitive with other methods. The goal was to schedule as many supports as …

A Fortran Based Learning System Using Multilayer Back-Propagation Neural Network Techniques, Gregory L. Reinhart

Theses and Dissertations

An interactive computer system which allows the researcher to build an optimal neural network structure quickly, is developed and validated. This system assumes a single hidden layer perceptron structure and uses the back- propagation training technique. The software enables the researcher to quickly define a neural network structure, train the neural network, interrupt training at any point to analyze the status of the current network, re-start training at the interrupted point if desired, and analyze the final network using two- dimensional graphs, three-dimensional graphs, confusion matrices and saliency metrics. A technique for training, testing, and validating various network structures and …

Assessing The Vulnerability Of Multi-Commodity Networks With Failing Components, Alan R. Robinson

Theses and Dissertations

This research proposes an analytical approach for assessing flow disturbance, or compromise, based on limited sampling of arc flow information in multi-commodity, or multiple origin-destination O-D, networks with failing arcs. There were three objectives established for this research. The first objective was to bound the expected flow, given the arcs fail with certain probabilities, which was accomplished by reviewing current approaches for single-commodity networks and extending the results to the multi-commodity case. The second objective was to determine the best placement of flow monitors to obtain the most accurate estimates of O-D pair volumes. This was accomplished using a multi-criteria …

The Effective Use Of Animation In Simulation Model Validation, Christopher L. Swider

Theses and Dissertations

This study examined two animation displays moving icons, bar graphs at two presentation speeds to determine how each of these factors affected the animations ability to communicate violations of model assumptions. Subjects viewed animation displays individually and in combination at each presentation speed. Eight problem scenarios were presented to evaluate each animations ability to communicate violations of different assumptions. Each animations communication ability was measured subjectively and objectively. Subjective measures in the form of pairwise comparisons were used to calculate normalized preference ratings for each animation. objective measures included problem identification accuracy and problem time. Subjective results indicated that moving …

An Rsm Study Of The Effects Of Simulation Work And Metamodel Specification On The Statistical Quality Of Metamodel Estimates, Michael K. Taylor

Theses and Dissertations

This research investigated the combined influence of simulation work and metamodel specification on the statistical quality of the estimates obtained from the resulting metamodels of the simulation data. A 9 x 2 x 2 experiment consisting of 9 cases of simulation work, 2 levels of metamodel specification, and 2 levels of design fractionation were designed for 8 different configurations of MMk queues. The only observed statistic for this experiment was the average queue length. Simulation estimates for each configurations average queue length were calculated directly from the simulation data. In addition, the metamodels were fit to the simulation data and …

Proactive Monitoring Of Performance In Stochastic Communication Networks, John C. C. Van Hove

Theses and Dissertations

This research proposes several models for placing bounds on the expected values of some dynamic performance measures for computer communication networks with failing components. These models provide an understanding of expected network performance that is useful in the process of proactive performance monitoring and also in defining level of service agreements with network users. There were three objectives for this research. The first objective was to extend some existing models of steady-state stochastic network performance to a dynamic network flow representation in order to capture the dynamic nature of proactive monitoring. The second objective was to convert the extended absolute …

Analysis Of Thunder Combat Simulation Model, Timothy S. Webb

Theses and Dissertations

TAC THUNDER, or THUNDER, is a two-sided large scale computer simulation model that simulates air and ground combat, logistics, and limited airlift at the theater level. It is in use by several allied nations, major defense contractors, and various Department of Defense DoD analysis agencies. The objectives of this thesis effort were to examine the overall model variability, examine the model output for possible interrelationships, and examine the model sensitivity to input parameters. A univariate and multivariate analysis was performed to examine the first two objectives. The univariate analysis consisted of an analysis of the confidence intervals and replication requirements …

Optimization Of The Air Apportionment In A Tac Thunder Scenario Using Response Surface Methodology, Steven L. Forsythe

Theses and Dissertations

To effectively compare different sets of available aircraft, it is necessary to find the apportionment that maximizes the effectiveness of each set of aircraft. This research effort uses an unclassified TAC THUNDER scenario to show how an analyst can use response surface methodology RSM techniques to estimate the relationship between aircraft apportionment and campaign outcomes. The optimal apportionments for one phase of a hypothetical conflict was found by using a steepest-gradient search of the constrained response surfaces. The results are illustrated by illuminating charts showing the various relationships between the number of aircraft in the theater and measures of effectiveness …

An Integer Solution Heuristic For The Arsenal Exchange Model (Aem), Daniel J. Green

Theses and Dissertations

The Air Force Studies and Analyses Agency sought a method for converting the continuous solution produced by the Arsenal Exchange Model into a feasible integer solution. The current integerization method leaves weapons unused and targets uncovered and could be improved. In the method developed, the noninteger valued variables in the continuous solution are rounded down to the nearest integer to produce a truncated solution. An integer goal program is then used to reallocate the weapons and targets made available in the rounding process. The truncated solution is then combined with the solution of the integer goal program to produce a …

An Air Mission Planning Algorithm For A Theater Level Combat Model, Brian J. Griggs

Theses and Dissertations

This thesis describes the development of an air mission planning algorithm for the Joint Staffs Future Theater Level Model FTLM. The overall problem scope was to develop an algorithm to handle major factors bearing on the combat mission planning problem while providing hook-ups for the FTLM architecture. Other aspects of the problem included finding the appropriate level of detail, developing a fast solving technique, and attempting to use existing data. The problem was handled by using some ideas from existing aircraft allocation algorithms and by adding some new techniques. The proposed air mission planning algorithm supplies the optimum degree of …

An Analysis Of Stopping Criteria In Artificial Neural Networks, Bruce Kostal

Theses and Dissertations

The goal of this study was to decide when to terminate training of an artificial neural network ANN. In pursuit of this goal, several characteristics of the ANN were monitored throughout ANN training classification error rate of the training set, testing set, or a weighted average of the two moving average classification error rate measurements of the difference between ANN output and desired output error sum of squares, total absolute error. or largest absolute error or ANN weight changes absolute weight change, squared weight change, or relative weight change. Throughout this research, the learning rate was held constant at 0.35. …

An Investigation Of Simulated Annealing Applied To Structural Optimization Problems, Richard C. Mceachin

Theses and Dissertations

This thesis investigates the feasibility of using Simulated Annealing SA in structural optimization problems. The investigation involves solving benchmark structural optimization problems with an SA algorithm, and comparing its solutions to those found by four other optimizers. Overall, the analysis shows that SA has limited applicability in structural optimization. Two primary factors were found to adversely impact the performance of the SA algorithm in these problems. These factors are high dimensionality, and high levels of constraint. The difficulty involved in solving these problems with a random search increases exponentially with the number of dimensions. The number, and non-linearity, of the …

An Analysis Of Air Force Acquisition Engineering Officer's Perceptions Of The Adequacy Of Their Preparation For Management, Steven E. Woodruff

Theses and Dissertations

The purpose of this study was to determine how much time Air Force acquisition engineers spend in performing management functions, how those engineers spend in performing management functions, how those engineers perceive their management training, and which types of training contribute the most to managerial competency. The results from surveys of 215 acquisition engineers assigned to ASCEN, Wright-Patterson AFB, OH and their supervisors revealed that engineers do indeed spend substantial amounts of time performing management functions. Slightly more than half the engineers reported spending at least 50 of an average workday performing management functions. Over 53 of engineers responding to …

Free Vibrations Of A Piezoelectric Body, J. S. Yang, R. C. Batra

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We present a systematic analysis of the eigenvalue problem associated with free vibrations of a finite piezoelectric body. The analysis is based on an abstract formulation of the three-dimensional theory of piezoelectricity. A series of fundamental properties of free vibrations of a piezoelectric body are proved concisely. The problem of free vibrations of a piezoelectric plate governed by the two-dimensional plate equations due to Mindlin is treated in a similar manner. © 1994 Kluwer Academic Publishers.

Kinetics Of Egg Production And Egg Excretion By Schistosoma Mansoni And S. Japonicum In Mice Infected With A Single Pair Of Worms, A. W. Cheever, J. G. Macedonia, J. E. Mosimann, Erik Allen Cheever , '82

Engineering Faculty Works

Individual male and female schistosomes approximately three weeks of age were implanted into the portal venous system of C57Bl/6 mice to produce infections with a single pair of Schistosoma mansoni or S. japonicum. Mice were killed between seven and 53 weeks after infection. Worm fecundity was measured by counting eggs accumulating in the tissues and eggs passed in the feces. Schistosoma mansoni worm pairs laid approximately 350 eggs per day with no change in the apparent rate of egg laying between eight and 52 weeks after infection and approximately one-third of the eggs were passed in the feces. Schistosoma japonicum …

Natural History Of Schistosoma Mansoni Infection In Mice: Egg Production, Egg Passage In The Feces, And Contribution Of Host And Parasite Death To Changes In Worm Numbers, A. W. Cheever , '82, J. E. Mosimann, S. Deb, Erik Allen Cheever , '82, R. H. Duvall

Engineering Faculty Works

Mice, C57B1/6N (B6) and BALB/cAnN (BALB), infected with Schistosoma mansoni were examined 8-26 weeks postinfection (PI) to estimate the fecundity of the worms and the contribution of death of worms and the death of heavily infected mice to the decrease in worm numbers in chronic infections. Portal worms were recovered by perfusion and the lungs were examined for parasites shunted from the portal circulation. Animals that died were more heavily infected than those that survived. Between eight and 12 weeks PI, this loss of worms resulted in a net decrease of approximately 19% of worm Fairs in surviving BALB mice, …

Overview Of Federal Technology Transfer, Lawrence Rudolph

RISK: Health, Safety & Environment (1990-2002)

Mr. Rudolph reviews approximately thirteen years of legal and political developments that have contributed to laws governing the extent to which private firms may secure rights in technology at least partly developed with federal funds.

Pancreatic Islet Production Of Murine Interleukin-10 Does Not Inhibit Immune-Mediated Tissue Destruction., Myung-Shik Lee, Lise Wogensen, Judith Shizuru, Michael B.A. Oldstone, Nora Sarvetnick

Journal Articles: Regenerative Medicine

IL-10 inhibits macrophage-dependent antigen presentation, cytokine production, and generation of allospecific cells in vitro. These findings have lead to the widespread expectation that IL-10 may be a useful immunosuppressive agent to inhibit allograft rejection or autoimmunity in vivo. We used two experimental paradigms to study effects of murine IL-10 on in vivo immune responses. First, fetal pancreata or adult pancreatic islets from transgenic mice expressing IL-10 in pancreatic beta cells (Ins-IL-10 mice) were grafted across the MHC barrier to examine if IL-10 could inhibit allograft rejection. Second, Ins-IL-10 mice were crossed with transgenic mice expressing lymphocytic choriomeningitis virus (LCMV) antigens …

Integrated Embedding Optimization Applied To Salt Lake Valley Aquifers, A. Gharbi, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

The embedding optimization modeling approach is adapted to aid sustainable groundwater quantity and quality management of complex nonlinear multilayer aquifers. Implicit block-centered finite difference approximations of the quasi three-dimensional unsteady flow equation and Galerkin finite element approximations of the two-dimensional advection-dispersion transport equation are embedded directly as constraints in the model. Also used are nonlinear constraints describing river-aquifer interflow, evapotranspiration, and vertical flow reduction due to unconfinement. These circumvent use of large numbers of integer variables. The use of both linear and nonlinear formulations in a cyclical manner reduces execution time and improves confidence in solution optimality. The methodology is …

Rapid And Accurate Timing Simulation Of Radiation-Hardened Digital Microelectronics Using Vhdl, Charles P. Brothers Jr.

Theses and Dissertations

This dissertation presents the development of a fast, accurate, timing simulation capability based on VHSIC Hardware Description Language VHDL without the use of back annotation of timing delay information. This VHDL-based timing simulator is intended for use with radiation-hardened microelectronics in simulating timing of circuit operation in pre-radiation, post-radiation 1 MradSi total dose, and ionizing dose radiation environments. Development of the timing models are presented. The implementation of the timing models are incorporated into a VHDL library composed of basic logic gates and flip-flops. Simulations of complex circuits were run in SPICE and VHDL to assess the timing accuracy and …

Compression Of A Radar Track Of A Near Earth Satellite Into An Earth Centered Inertial State Vector Using Least Squares Differential Correction, Garry L. Hall

Theses and Dissertations

This study investigated the use of a least squares differential corrector to compress the information contained in a single radar track of a Near Earth satellite into a six element, Earth Centered Inertial state vector and associated covariance matrix. Observations were generated using a truth model program based on two body, J2 geopotential, and atmospheric drag dynamics and consisted of simulated range, azimuth and elevation. Random Gaussian noise was added to the data to simulate real world random errors. The orbital dynamics used in the estimator consisted of two body and J2 geopotential effects which were approximated using a Taylor …