Digital Commons Network^™

A Study Of Cumulative Trauma Disorders Of The Upper Extremities And Occupation In Wright-Patterson Adir Force Base Civilian Personnel, Scott T. Hillstead

Theses and Dissertations

This study utilized a case-control methodology to describe and analyze the 115 cases of occupational illnesses reported by civilian employees of Wright-Patterson Air Force Base (AFB) between 1990 and 1995. Determining if a statistically significant association existed between age and duration of employment risk factors and cumulative trauma disorders (CTDs) was a primary objective. The frequency of CTDs among the various organizations at Wright-Patterson AFB are also described. The research could not prove the existence of a significant association for the 44 subjects and 176 controls matched on occupational group. However, the demographic and other descriptive results may form a …

A Preliminary Analysis Of The Theoretical Parameters Of Organizational Learning, Jeffery D. Loyd

Theses and Dissertations

The goal of this research was to develop an instrument capable of measuring the theoretical parameters of organizational learning that could be used as a diagnostic tool to measure an organization's learning potential. This goal was accomplished by developing a pilot questionnaire based on 27 potential learning parameters. The potential parameters of learning were extracted from the literature. A scale of behavioral statements was developed for each potential parameter. The pilot questionnaire was completed by 108 Air Force personnel in Air Force Institute of Technology (AFIT) graduate education programs. The results confirmed 85% of the original scales. Ten refined scales …

The Implementation Of Federal Government Policy In The Reuse Planning Of Military Installations: A Case Study Of Gentile Air Force Station, John L. Hoover

Theses and Dissertations

Local communities affected by a base closure are uncertain as to their future and look to the federal government for guidance and economic assistance in rebuilding their local economy. The local communities want to close the base with as little federal government interference as possible and convert the base to civilian use with as much federal financial assistance as possible. During 1993-1994 two Air Force Institute of Technology research teams began longitudinal case studies of the base closure and rescue process at Gentile Air Force Station, Ohio to determine the effectiveness of the federal government's current approach. These research teams …

A Robust Method Of Solving Nonlinear Boundary Value Problems Via Modified Compromise Programming, John L. Zornick

Theses and Dissertations

This study is an extension of Ng's previous work in which goal programming was used to determine an approximate solution to a boundary value problem. This approach follows the same basic approach developed by Ng in which the method of collocation was recast as a compromise programming model. Hence, instead of solving a system of simultaneous nonlinear equations, one seeks a compromise solution which minimizes (in a weighted residual sense) a vector norm of the differential equation residuals. A difference in this approach is that it makes use of a genetic algorithm as the optimizing engine as opposed to the …

A New Goodness-Of-Fit Test For The Gamma Distribution Based On Sample Spacings From Complete And Censored Samples, Huseyin Duman

Theses and Dissertations

This thesis studies a new goodness-of-fit test for the gamma distribution with known shape parameter. This test statistic, Z*, is based on spacings from complete or censored samples. The size of samples varied between 5 and 35. The critical value tables were generated for the Z* test statistic for complete and censored samples. The critical values were obtained for five different significance levels: 0.20 0.15, 0.10, 0.05, and 0.01. An extensive power study, containing 50,000 Monte Carlo runs was conducted using nine alternative distributions, H_a. It was observed that the Z* test statistic was more powerful against certain …

Acquiring Consistent Knowledge For Bayesian Forests, Darwyn O. Banks

Theses and Dissertations

This thesis develops a methodology and a tool for knowledge acquisition with the new probabilistic knowledge representation-the Bayesian Forest. It establishes the structure of the Knowledge Acquisition and Maintenance module of the Probabilities. Expert Systems, Knowledge and Inference (PESKI) architecture. The tool, MACK, is designed to be used directly by the domain expert(s) rather than by knowledge engineer(s), and thus supports automated knowledge acquisition. This research determines and implements the constraints necessary to ensure the consistency of Bayesian Forest knowledge bases as data is both acquired and subsequently maintained. The impact to the PESKI architecture of time-dependent information and default …

Response Surface Methodology As A Sensitivity Tool In Decision Analysis, David A. Meyers

Theses and Dissertations

The purpose of this study is to evaluate response surface methodology as a sensitivity analysis tool in the area of decision analysis. The advent of low-cost personal computer software, such as DPLTM, has created an accessible tool with the ability to frame and solve influence diagrams for decision problems. This study provides a comparison of current sensitivity analysis techniques vs those made possible through response surface methodology (RSM). Sensitivity analysis alternatives are demonstrated on a decision problem concerning the evaluation of force structure options for the Department of Defense. Sensitivity analysis is performed on both one-way and two-way perturbations of …

Groundwater Model Parameter Estimation Using Response Surface Methodology, Richard M. Cotman

Theses and Dissertations

This thesis examined the use of response surface methodology (RSM) to estimate the parameters of a finite-element groundwater model. An existing two-dimensional, steady-state flow model of a fractured carbonate groundwater system in southwestern Ohio served as the calibration target data set. A Plackett-Burman screening design showed that only four of the ten hydraulic conductivity zones significantly contributed to the output of the finite-element model. Also, the effective porosity parameter did not significantly affect the model's output. Using only the four significant hydraulic conductivity parameters; four two-level, four-factor designed experiments were conducted to exploit the first-order response surface defined by a …

Spatial Time-Series: Pollution Pattern Recognition Under Irregular Interventions, Samuel A. Wright

Theses and Dissertations

The Fernald Environmental Restoration Management Corporation (FERMCO) has noted the introduction of arsenic contamination to groundwater around the area of the groundwater recovery system, which captures uranium contaminated groundwater. The introduction of arsenic occurs during high levels of pumping and is particularly sensitive to the western two of the five pumps. Auto-Regressive Moving Average (ARMA) and Spatial-Temporal ARMA (STARMA) empirical analyses are used to model the level of arsenic contamination found through time. The intervention of varied levels of pumping is modeled with a transfer function using analytic techniques to create a causal intervention transfer function input series to give …

Estimation Of The Captive-Carry Survival Function For The Advanced Medium Range Air-To-Air Missile (Amraam), David R. Denhard

Theses and Dissertations

This thesis considers the problem of estimating the survival function of an item (probability that the item functions for a time greater than a given time t) from sampling data subject to partial right censoring (a portion of the items in the sampling data have not yet been observed to fail). Specifically the thesis describes several parametric and non-parametric statistical models that can be used when the sampling data is subject to partial right censoring. These models are applied to the case of estimating the captive-carry survival function of the AIM-120A Advanced Medium Range Air-to-Air Missile (AMRAAM).

Estimating Groundwater Flow Parameters Using Response Surface Methodology, Leo C. Adams

Theses and Dissertations

This thesis examined the use of response surface methodology RSM as a parameter estimation technique in the field of groundwater flow modeling. Using RSM, an attempt was made to calibrate three hydraulic parameters porosity, transverse permeability, and rate of recharge of an existing two- dimensional, steady-state flow model. The model simulated groundwater flow for a portion of landfill 10 located on Wright-Patterson Air Force Base, Ohio. The model had previously been calibrated by graphical matching observed water-levels to predicted water-levels. Using the parameter values from the earlier calibration effort as a starting point, a central composite design was developed 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 …

An Analysis Of Operational Suitability For Test And Evaluation Of Highly Reliable Systems, James N. Serpa

Theses and Dissertations

The purpose of this research was to develop a quantitative measure of operational suitability OS and determine its applicability in making the test length decision prior to Initial Operational Test and Evaluation IOTE. The current approach used by the Air Force Operational Test and Evaluation Center AFOTEC was presented and used to establish the relationships of the test measures. It was established that OS could be represented by a function of operational availability Ao and built-in test effectiveness BE. BE was defined and measures proposed based on the method of data collection. A proposal for predicting Ao, BE, and OS …

The Use Of L-Moments To Fit The Generalized Lambda Distribution To Sample Data, Robert B. Mohan

Theses and Dissertations

The Generalized Lambda Distribution GLD is a four-parameter, continuous probability distribution that is useful for simulation analysis. The strengths of the GLD lie in its abilities to approximate many distributions, represent data when the underlying distribution is unknown, and fit or generate random variates. The method of moments is presently the accepted technique for estimating the parameters of this distribution. However, it is sensitive to extreme observations and subject to large sampling variability as the sample size decreases. L-moments are expectations of certain linear combinations of order statistics. They can be used to estimate parameters and quantiles of probability distributions. …

A Comparison Of Variable Selection Criteria For Multiple Linear Regression: A Third Simulation Study, Ertem Mutlu

Theses and Dissertations

The goal of this thesis research is to introduce and study a modification of Millers Method which we call the Modified-Millers method MM method, study two step subset selection procedures, these of which apply Millers Method in the first step and employs another method Minimum MSE or Minimum Sp or Minimum Cp in the second step and these of which employ another method Minimum MSE or Minimum Sp or Minimum Cp in the first step and applies Millers Method in the second step. The results of all techniques will be compared including the results of the previous simulation studies done …

Several Modified Goodness-Of-Fit Tests For The Cauchy Distribution With Unknown Scale And Location Parameters, Bora H. Onen

Theses and Dissertations

Kolmogorov-Simirnov and the Kuiper goodness-of-fit tests are studied for the Cauchy distribution with the unknown location and scale parameters. Monte Carlo simulation studies were performed using maximum likelihood estimation to calculate the critical values for standard Kolmogorov-Simirnov and the Kuiper tests. Then a reflection technique is introduced and the critical value tables are calculated for both the Reflected Kolmogorov-Simirnov and the Reflected Kuiper tests. Several sequential tests are performed by combining standard Kolmogorov-Simirnov and Kuiper in one test, standard Cramer-von Mises and the standard Kuiper in the other and finally the reflected Cramer-von Mises and the standard Kuiper in the …

Predicting Missionary Service, Bert Burraston

Theses and Dissertations

The purpose of this thesis was to test the antecedents of religiosity on religious commitment. Specifically, what dimensions of religiosity predict if a young-adult Mormon male will serve a mission. Both Logistic Regression and LISREL were used to examine data from the Young Men's Study, in order to predict Mission. The six variables, Religious Intention, Public Religiosity, Religious Negativism, Family Structure, Tithing, and Smoking were found to have direct effects on missionary service. Four more variables were found to have important indirect effects on Mission. The four variables are Parents Church Attendance, Home Religious Observances, Agree With Parents' Values, and …

The Standardized Influence Matrix And Its Applications To Generalized Linear Models, Jiandong Lu

Theses and Dissertations

The standardized influence matrix is a generalization of the standardized influence function and Cook’s approach to local influence. It provides a general and unified approach to judge the suitability of statistical inference based on parametric models. It characterizes the local influence of data deviations from parametric models on various estimators, including generalized linear models. Its use for both robustness measures and diagnostic procedures has been studied. With global robust estimators, diagnostic statistics are proposed and shown to be useful in detecting influential points for linear regression and logistic regression models. Robustness of various estimators is compared via. the standardized influence …

Developing Prediction Regions For A Time Series Model For Hurricane Forecasting, William Cheman

Theses and Dissertations

In this thesis, a class of time series models for forecasting a hurricanes future position based on its previous positions and a generalized model of hurricane motion are examined and extended. Results of a literature review suggest that meteorological models continue to increase in complexity while few statistical approaches, such as linear regression, have been successfully applied. An exception is provided by a certain class of time series models that appear to forecast storms almost as well as current meteorological models without their tremendous complexity. A suggestion for enhancing the performance of these time series models is pursued through an …

Solving The Ranking And Selection Indifference-Zone Formulation For Normal Distributions Using Computer Software, Catherine A. Poston

Theses and Dissertations

Ranking and selection procedures are statistical methods used to compare and choose the best among a group of similar statistically distributed populations. The two predominant approaches to solving ranking and selection problems are Guptas subset selection formulation and Bechhofers indifference- zone formulation. For the indifference-zone formulation where the populations have equal sample sizes, Barr and Rizvi developed an integral expression of the probability of correct selection PCS. Given appropriate parameters, the integral expression can be solved to determine the common sample size required to attain a desired PCS. Tables with selected solutions to the integral expression are available for a …

A Parametric Regression Of The Cost Of Base Realignment Action (Cobra) Model, Douglas Hardman, Michael Nelson

Theses and Dissertations

This study develops a parametric model that is capable of generating accurate estimates of the costs to close Air Force installations. The new model is based upon, but much simpler to use than, the Cost of Base Realignment Action (COBRA) model. COBRA is an economic cost analysis model that requires a minimum of 250 inputs and as many as 700 inputs. The new parametric model requires just 10 input variables and was developed using least squares multiple regression. Comparison of the new parametric model to COBRA indicates that it captures 91 percent of the variance in cost estimates generated by …

Identification Of Significant Outliers In Time Series Data, Keri L. Robinson

Theses and Dissertations

This thesis examines the feasibility of using least median of squares (LMS) procedure applied to a reweighted least squares (RLS) autoregression model to identify significant outliers in time series data. The time series were analyzed for data points that were outliers. In order to perform detailed analysis on an outlier. the analyst must be able to determine that an outlier data point is significantly different from normally distributed data. This thesis examines a new method for identifying these outliers. Data from the field were characterized and fit with time series models using an autoregressive reweighted least squares routine (ARRLS) derived …

Modified Anderson-Darling And Cramer-Von Mises Goodness-Of-Fit Tests For The Normal Distribution, David A. Gwinn Sr.

Theses and Dissertations

New techniques for calculating goodness-of-fit statistics for normal distributions with parameters estimated from the sample are investigated. Samples are generated for a Normal(0,1) distribution. Critical values are calculated for five modifications to the Anderson-Darling statistic and five modifications to the Cramer-Von Mises statistic. An extensive power study is done to test the power of the new statistics versus the power of the unmodified statistics. Powers of six of the new statistics show minimal to no improvement, two of the new statistics show a marked decrease in power, and two of the new statistics show an overall increase in power over …

A Modified Anderson Darling Goodness-Of-Fit Test For The Gamma Distribution With Unknown Scale And Location Parameters, Tamer Ozmen

Theses and Dissertations

A new modified Anderson-Darling goodness-of-fit test is introduced for the three-parameter Gamma distribution when the location parameter is found by minimum distance estimation and scale parameter by maximum likelihood estimation. Monte Carlo simulation studies were performed to calculate the critical values for A-D test when A-D statistic is minimized. These critical values are then used for testing whether a set of observations follows a Gamma distribution when the scale and location parameters axe unspecified and are estimated from the sample. Functional relationship between the critical values of A-D is also examined for each shape parameter by the variables, sample size …

A Modified Chi-Squared Goodness-Of-Fit Test For The Three-Parameter Gamma Distribution With Unknown Parameters, Thomas J. Sterle

Theses and Dissertations

A modified chi-squared goodness-of-fit test was created for the gamma distribution in the case where all three parameters must be estimated from the sample. Critical values are generated using a Monte Carlo simulation procedure with 5000 repetitions each. Random samples of 8 different sizes were drawn from gamma distributions with shape parameters 1, 1.5, 2., and 2.5. The shape, scale, and location parameters were then estimated from each sample, using an iterative technique combining the maximum likelihood and minimum distance methods, enabling, computation of the chi-squared statistics and critical values. The same process is used to generate random samples, parameter …

A New Goodness-Of-Fit Test For The Weibull Distribution Based On Spacings, Mark C. Coppa

Theses and Dissertations

The critical values for a new goodness-of-fit test based on spacings are generated for the Weibull distribution when the shape parameter is known. The critical values are used for testing whether a set of observations follow a Weibull distribution when the scale and location parameters are unknown. A Monte Carlo simulation with 10,000 iterations is used to generate the critical values for sample sizes 5(5)35 at shape parameters k equal to 0.5(0.5)1.5 and for sample sizes 5(5)20 at shape parameters k = 2.0(1.0)4.0. A Monte Carlo power study of the Z* test statistic using 5000 iterations is accomplished using nine …

A Comparison Of Variable Selection Criteria For Multiple Linear Regression: A Second Simulation Study, David P. Woollard

Theses and Dissertations

This thesis implements a variable selection method proposed by Alan J. Miller, and makes an extension of Ross J. Hansen's 1988 thesis research by comparing the methods he examined: Minimum MSE, Minimum Sp, and Minimum Cp with Miller's method. Response Surface methodology is employed with two performance measures: the percentage of correct variables in a model and the Theoretical Mean Squared Error of Prediction (TMSEP). Each technique is applied on generated data with known multicollinearities, variances, random predictors, and sample sizes. Both performance measures are computed for models selected under each technique. A full factorial design using each performance measure …

Radar Cross Section Models For Limited Aspect Angle Windows, Mark C. Robinson

Theses and Dissertations

This thesis presents a method for building Radar Cross Section (RCS) models of aircraft based on static data taken from limited aspect angle windows. These models statistically characterize static RCS. This is done to show that a limited number of samples can be used to effectively characterize static aircraft RCS. The optimum models are determined by performing both a Kolmogorov and a Chi-Square goodness-of-fit test comparing the static RCS data with a variety of probability density functions (pdf) that are known to be effective at approximating the static RCS of aircraft. The optimum parameter estimator is also determined by the …

Object Tracking Through Adaptive Correlation, Dennis A. Montera

Theses and Dissertations

This paper discusses the use of a correlation based system to track, an object through a series of images based on templates derived from previous image frames. The ability to track is extended to sequences which include multiple objects of interest within the field of view. This is accomplishes by comparing the height and shape of the template autocorrelation to the peaks in the correlation of the template with the next scene. The result is to identify the region in the next scene which best matches the designated target. In addition to correlation plane postprocessing, an adaptive window is used …

Missing Data In Repeated Measurement Studies, Kejian Niu

Theses and Dissertations

Repeated measurement data or longitudinal data occur often in statistical applications. For example, in a clinical trial comparing the efficacy of a new treatment with that of a standard treatment, rather than measuring the main response variable only once on each patient, or subject, we can take several measurements over time on each subject.

A Repeated measurement study differs from a longitudinal study. The latter generally refers to any study in which one or more response variables are repeatedly measured over time. The former usually imposes some restrictions on the data. One common restriction is that each response variable must …