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Full-Text Articles in Physical Sciences and Mathematics

Estimating Groundwater Flow Parameters Using Response Surface Methodology, Leo C. Adams Apr 1994

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 …


A Comparison Of Variable Selection Criteria For Multiple Linear Regression: A Third Simulation Study, Ertem Mutlu Mar 1994

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 Mar 1994

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 …


An Analysis Of Operational Suitability For Test And Evaluation Of Highly Reliable Systems, James N. Serpa Mar 1994

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 …


Proactive Monitoring Of Performance In Stochastic Communication Networks, John C. C. Van Hove Mar 1994

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 …


The Use Of L-Moments To Fit The Generalized Lambda Distribution To Sample Data, Robert B. Mohan Mar 1994

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. …


Predicting Missionary Service, Bert Burraston Jan 1994

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 Jan 1994

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 …