Physical Sciences and Mathematics Commons^™

Computer-Based Methods For Constructing Two-Level Fractional-Factorial Experimental Designs With A Requirement Set, Steven L. Forsythe

Theses and Dissertations

This dissertation developed four methodologies for computer-aided experimental design of two-level fractional factorial designs with requirement sets (DOE/RS). The requirement sets identify all the experimental factors and the appropriate interaction terms to be evaluated in the experiment. Taguchi graphs and similar manual methods provide techniques for solving the DOE/RS problem. Unfortunately, these methods are limited because they become difficult to use as the number of factors or interaction terms exceeds ten. This research showed that the DOE/RS problem belongs to a class of difficult-to-solve problems known as NP-Complete. It is the combinatorial nature of NP-Complete problems that causes them to …

Fluid Flow In Micro-Channels: A Stochastic Approach, Hilda Marino Black

Doctoral Dissertations

In this study free molecular flow in a micro-channel was modeled using a stochastic approach, namely the Kolmogorov forward equation in three dimensions. Model equations were discretized using Central Difference and Backward Difference methods and solved using the Jacobi method. Parameters were used that reflect the characteristic geometry of experimental work performed at the Louisiana Tech University Institute for Micromanufacturing.

The solution to the model equations provided the probability density function of the distance traveled by a particle in the micro-channel. From this distribution we obtained the distribution of the residence time of a particle in the micro-channel. Knowledge of …

An Investigation Into Relationships Between Alternative Assessment And Pre-Service Elementary Teachers’ Beliefs About Mathematics, David Charles Coffey

Dissertations

The purpose of this study was to examine how including alternative assessments in a reform-based mathematics course affects pre-service teachers’ mathematical beliefs. A single section of a mathematics course designed for elementary education majors that employed three different alternative assessments was the setting for the study.

A pre- and post-belief survey completed by students enrolled in the section under study represented the first level of data collection and analysis. The results of the pre-belief survey guided the selection of seven informants from the section and provided belief statements for the informants to verify during subsequent interviews. Based on the data …

Rainbow Ramsey Numbers, Linda Eroh

Dissertations

No abstract provided.

An Extension Of Euclidean Distance Matrix Analysis Applied To Craniofacial Growth Prediction, Mark K. Batesole

Loma Linda University Electronic Theses, Dissertations & Projects

This study is [sic] introduces a new extension of Euclidean Distance Matrix Analysis (EDMA) as applied to growth prediction analysis. Using EDMA eliminates the presupposition of a set growth pattern, which is introduced by traditional superimposition techniques. When EDMA is extended to analyze prediction methodologies, using a non-age-matched growth sample, some shortcomings become evident. These involve bootstrapping techniques, relative difference in growth, and absence of clinical, real world measure. To overcome these issues, a statistical approach using the Wilcoxen signed rank test, absolute difference in growth, and a new method to evaluate the error in a prediction methodology's landmark identification …

Statistical Power Analysis Of Dissertations Completed By Students Majoring In Educational Leadership At Tennessee Universities, Heping Deng

Electronic Theses and Dissertations

The purpose of this study was to estimate the level of statistical power demonstrated in recent dissertations in the field of educational leadership. Power tables provided in Cohen's (1988) Statistical Power Analysis for the Behavioral Sciences were used to determine the power of the statistical tests conducted in dissertations selected from five universities in Tennessee. The meta-analytic approach was used to summarize and synthesize the findings. The population of this study consisted of all dissertations successfully defended by doctoral students majoring in educational leadership/administration at East Tennessee State University, the University of Tennessee at Knoxville, Tennessee State University, the University …

Cramer-Rao Bound And Optimal Amplitude Estimator Of Superimposed Sinusoidal Signals With Unknown Frequencies, Shaohui Jia

Doctoral Dissertations

This dissertation addresses optimally estimating the amplitudes of superimposed sinusoidal signals with unknown frequencies. The Cramer-Rao Bound of estimating the amplitudes in white Gaussian noise is given, and the maximum likelihood estimator of the amplitudes in this case is shown to be asymptotically efficient at high signal to noise ratio but finite sample size. Applying the theoretical results to signal resolutions, it is shown that the optimal resolution of multiple signals using a finite sample is given by the maximum likelihood estimator of the amplitudes of signals.

Bottom-Up Design Of Artificial Neural Network For Single-Lead Electrocardiogram Beat And Rhythm Classification, Srikanth Thiagarajan

Doctoral Dissertations

Performance improvement in computerized Electrocardiogram (ECG) classification is vital to improve reliability in this life-saving technology. The non-linearly overlapping nature of the ECG classification task prevents the statistical and the syntactic procedures from reaching the maximum performance. A new approach, a neural network-based classification scheme, has been implemented in clinical ECG problems with much success. The focus, however, has been on narrow clinical problem domains and the implementations lacked engineering precision. An optimal utilization of frequency information was missing. This dissertation attempts to improve the accuracy of neural network-based single-lead (lead-II) ECG beat and rhythm classification. A bottom-up approach defined …

Predicting Milk And Soft Drink Consumption Among Female Adolescents Using The Theory Of Planned Behavior, Nada Osman Kassem

Loma Linda University Electronic Theses, Dissertations & Projects

A total of 756 female adolescents, aged 13 to 18 years, from five public high schools in Antelope Valley Union High School District located in North Los Angeles County participated in this study between February 1999 and March 1999. The ethnic composition was 53.3% White/Anglo Americans, 19.3% Hispanics or Latinos and 10.2% Black/African Americans. The constructs of the Theory of Planned Behavior (attitude, subjective norm, and perceived behavioral control and their underlying beliefs) were assessed to determine the predictors of low-fat milk and regular soda consumption. A cross-sectional design with group-administered questionnaires was utilized.

Most participants (89.6%, n = 636) …

Risk Factors Associated With Infant Mortality Among Very Low Birthweight Infants Of Teenage Mothers In San Bernardino County, C. Letitia Henry

Loma Linda University Electronic Theses, Dissertations & Projects

Background. Typically, infant mortality decreases as maternal age increases in teenagers. In contrast to these national data, San Bernardino County (SBC) experienced a different phenomenon in 1989-1994 among very low birthweight (VLBW) infants. The infant mortality rate (IMR) of VLBW infants born to mothers under 17 years old (283 per 1000 live births) was significantly lower than the IMR of VLBW infants born to mothers between the ages of 17-19 years old (430 per 1000 live births) (p = .02).

Purpose. The purpose of the study was to explain the discrepancy between IMRs of VLBW infants of younger teenage mothers …