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Markovian And Stochastic Differential Equation Based Approaches To Computer Virus Propagation Dynamics And Some Models For Survival Distributions, Lianzhe Xu

Dissertations

This dissertation is divided in two Parts. The first Part explores probabilistic modeling of propagation of computer 'malware' (generally referred to as 'virus') across a network of computers, and investigates modeling improvements achieved by introducing a random latency period during which an infected computer in the network is unable to infect others. In the second Part, two approaches for modeling life distributions in univariate and bivariate setups are developed.

In Part I, homogeneous and non-homogeneous stochastic susceptible-exposed-infectious- recovered (SEIR) models are specifically explored for the propagation of computer virus over the Internet by borrowing ideas from mathematical epidemiology. Large computer …

Optimizing Resource Allocation In Next-Generation Optical Access Networks, Jingjing Zhang

Dissertations

To meet rapidly increasing traffic demands caused by the popularization of Internet and the spouting of bandwidth-demanding applications, Passive Optical Networks (PONs) exploit the potential capacities of optical fibers, and are becoming promising future-proof access network technologies. On the other hand, for a broader coverage area and higher data rate, integrated optical and wireless access is becoming a future trend for wireless access. This thesis investigates three next-generation access networks: Time Division Multiplexing (TDM) PONs, Wavelength Division Multiplexing (WDM) PONs, and WDM Radio-Over-Fiber (RoF) Picocellular networks.

To address resource allocation problems in these three networks, this thesis first investigates respective …

Sequential Bayesian Filtering For Spatial Arrival Time Estimation, Rashi Jain

Dissertations

Locating and tracking a source in an ocean environment as well as estimating environmental parameters of a sound propagation medium is of utmost importance in underwater acoustics. Matched field processing is often the method of choice for the estimation of such parameters. This approach, based on full field calculations, is computationally intensive and sensitive to assumptions on the structure of the environment. As an alternative, methods that use only select features of the acoustic field for source localization and environmental inversion have been proposed. The focus here is on inversion using arrival times of identified paths within recorded time-series. After …

Applications Of Stochastic Simulation In Two-Stage Multiple Comparisons With The Best Problem And Time Average Variance Constant Estimation, Dibyendu Chakrabarti

Dissertations

In this dissertation, we study two problems. In the first part, we consider the two-stage methods for comparing alternatives using simulation. Suppose there are a finite number of alternatives to compare, with each alternative having an unknown parameter that is the basis for comparison. The parameters are to be estimated using simulation, where the alternatives are simulated independently. We develop two-stage selection and multiple-comparison procedures for simulations under a general framework. The assumptions are that each alternative has a parameter estimation process that satisfies a random- time-change central limit theorem (CLT), and there is a weakly consistent variance estimator (WCVE) …

Uniform Heating Of Thin Ceramic Slabs In A Multimode Microwave Cavity, Shuchi Agrawal

Dissertations

Two-dimensional reaction diffusion equations, which contain a functional and an inhomogeneous source term, are good models for describing microwave heating of thin ceramic slabs and cylinders in a multi mode, highly resonant cavity. A thin ceramic slab situated in a TEN03 rectangular cavity modeled in the small Biot number limit and a thin silicon wafer situated in a TM101 cylindrical cavity modeled in the small fineness ratio limit are studied to gain insight into the dynamics of the heating process. The evolution of temperature is governed by a two-dimensional reaction diffusion equation and a spatially non-homogeneous reaction term. Numerical methods …

Asymptotic And Numerical Analysis Of Time-Dependent Wave Propagation In Dispersive Dielectric Media That Exhibit Fractional Relaxation, Matthew Frank Causley

Dissertations

This dissertation addresses electromagnetic pulse propagation through anomalously dispersive dielectric media. The Havriliak-Negami (H-N) and Cole-Cole (C-C) models capture the non-exponential nature of such dielectric relaxation phenomena, which is manifest in a variety of dispersive dielectric media. In the C-C model, the dielectric polarization is coupled to the time-dependent Maxwell's equations by a fractional differential equation involving the electric field. In the H-N case, a more general pseudo-fractional differential operator describes the polarization.

The development and analysis of a robust method for implementing such models is presented, with an emphasis on algorithmic efficiency. Separate numerical schemes are presented for C-C …

Active Caching For Recommender Systems, Muhammad Umar Qasim

Dissertations

Web users are often overwhelmed by the amount of information available while carrying out browsing and searching tasks. Recommender systems substantially reduce the information overload by suggesting a list of similar documents that users might find interesting. However, generating these ranked lists requires an enormous amount of resources that often results in access latency. Caching frequently accessed data has been a useful technique for reducing stress on limited resources and improving response time. Traditional passive caching techniques, where the focus is on answering queries based on temporal locality or popularity, achieve a very limited performance gain. In this dissertation, we …

Application Of Raman Spectroscopy In Pharmaceuticals, Anna Zarow

Dissertations

Experimental research on the use of Raman spectroscopy as an in- and on-line sensing tool and a complementary characterization technique for pharmaceutical applications is presented in this thesis. In the first chapter following a broad overview, the use of Raman spectroscopy, together with x-ray powder diffraction, scanning electron microscopy (SEM) and differential scanning calorimetry, for multilevel characterization of cryomilled powders, and the melt-grown amorphous phase of griseofulvin, a model active pharmaceutical ingredient (API), is presented and discussed in detail. A key feature was the observation of a broad inelastic background superimposed on the Raman spectra of cryomilled powders, which is …

Numerical And Asymptotic Modeling Of Evolving Nonlinear Ocean Surface Wave Fields, Matt Malej

Dissertations

The main focus of this dissertation is the asymptotic and numerical modeling of nonlinear ocean surface wave fields. In particular, a development of an accurate numerical model for the evolution of nonlinear ocean waves, including extreme waves known as Rogue/Freak waves. Due to their elusive and destructive nature, the media often portrays Rogue waves as unimaginatively huge and unpredictable monsters of the sea. To address these concerns, derivations of asymptotically reduced models, based on the small wave steepness assumption, are presented and their corresponding numerical simulations via a Fourier pseudo-spectral method are discussed. The simulations are initialized with a well-known …

Some Contributions To Modeling Usage Sensitive Warranty Servicing Strategies And Their Analyses, Rudrani Banerjee

Dissertations

Providing a warranty as a part of a product's sale is a common practice in industry. Parameters of such warranties (e.g., its duration limits, intensity of use) must be carefully specified to ensure their financial viability. A great deal of effort has been accordingly devoted in attempts to reduce the costs of warranties via appropriately designed strategies to service them. many such strategies, that aim to reduce the total expected costs of the warrantor or / and are appealing in other ways such as being more pragmatic to implement - have been suggested in the literature. Design, analysis and optimization …

Using Feed-Forward Networks To Infer The Activity Of Feedback Neuronal Networks, Xinxian Huang

Dissertations

The nervous system is one of the most important organ systems in a multicellular body. Animals, including human beings perceive, learn, think and deliver motion instructions through their nervous system. The basic structural units of the nervous system are individual neurons which constitute different neuronal networks with distinct functions. In each network, constituent neurons are coupled with different connection patterns, for example, some neurons send feed-forward information to the coupling neurons while others are mutually coupled. Because it is often difficult to analyze large interconnected feedback neuronal networks, it is important to derive techniques to reduce the complexity of the …

Organizational Learning And Employee Retention: A Focused Study Examining The Role Of Relationships Between Supervisors And Subordinates, Veeranuch Vatcharasirisook

Dissertations

Focusing on the relationship between supervisors and subordinates, the purpose of this research was to study the causal relationship among seven exogenous variables (Supervisor empathy with subordinates, Supervisor trust of subordinates, Planning and delivery of instruction, Accommodating subordinate uniqueness, Supervisor insensitivity toward subordinates, Subordinate-centered learning process, and Supervisor-centered learning process) and two endogenous variables (Employee’s job satisfaction, and Employee’s intention to remain in the company). The study was based on the belief that the seven factors, which were beliefs, feelings, and behaviors of supervisors in helping adults learn, based on andragogical principles of learning, are not only methods to help …

Pre-Kindergarten And Kindergarten Teachers' Perceptions Of Kindergarten Readiness, Joshua Aaron Bressler

Dissertations

The purpose of this study was to determine if there was a difference in perception between pre-kindergarten and kindergarten teachers on kindergarten readiness. In addition, this study sought to find out if there was any difference in PEAK assessment scores between those students who attended pre-kindergarten versus those students who did not attend pre-kindergarten.

The instruments used for this research were the Pascagoula Early Assessment for Kindergarten (PEAK) scores and the Kindergarten Readiness Questionnaire. The PEAK scores measured students‟ readiness by assessing their knowledge on language, writing communication, math, and fine motor development from the onset upon entering kindergarten. The …

One-To-One Laptop Project: Perceptions Of Teachers, Parents, And Students, Matthew D. Constant

Dissertations

One-to-one laptop programs are becoming more prevalent across the world in K-12 institutions. School districts are searching for more engaging tools that seek to have impact on school success, such as grade achievement, college/career preparation, and/or 21st-century skill preparation and attainment. Additionally, boards of education continuously want some positive indication of the return on their substantial financial investment.

This study utilized surveys of three important stakeholder groups (parents, students, and teachers) related to a one-to-one laptop project in a moderately-sized rural Midwestern school district. Perceptions about how often laptops were used in the classroom setting and across content areas (Language …

Attitudes Toward Multimedia (Karaoke) And Popular Culture When Learning English As A Foreign Language In Taiwan, Chen-Yin Lee

Dissertations

No abstract provided.

Self-Efficacy And Retention Among Ethnically Diverse Nursing Students, Jacqueline Carol Lewis

Dissertations

No abstract provided.

Response To Intervention: Teachers' Needs For Implementation In Gifted And Talented Programs, Stephen Matthew Seedorf

Dissertations

There is a discrepancy currently in public schools when comparing the identification and instruction of underachieving students with gifted and talented students. A three tiered identification and instructional model was developed out of the Individuals with Disabilities Education Improvement Act (2004) with emphasis coming from the No Child Left Behind Act (2001). The Response to Intervention (RtI) model has proven to be a successful tool for identifying student need, implementing interventions, and monitoring the effectiveness of the interventions. This model has been explored for use with gifted and talented students, but the implementation in most schools has been lacking fidelity …

Saturday Academy: Student, Parent, And Teacher Perceptions Of An Intervention For At-Risk Middle School African American Students In A High Poverty School, Meoldy Latrice Witherspoon

Dissertations

I examined the perceptions of parents, students, and teachers of Saturday Academy, an intervention for students who are at risk of failing academically. The problem is that nearly half of students who attend high school may be at risk of dropping out before they graduate. The purpose of this study was to describe, evaluate, and analyze the perceptions of students, parents, and teachers of Saturday Academy. This study is significant because at-risk students are in need of an intervention that helps them to be successful at school. The study was conducted in a small middle school within a large school …

Student Achievement In Block And Non-Block Schedule Schools, William Shelton Smith Jr.

Dissertations

The purpose of this study was to determine if the number of minutes allocated for high school instructional periods influences student achievement. The study also examined the perceptions of principals regarding one method of instructional time allocation, block scheduling.

The study examined the differences in student achievement on a high school exit examination in the content areas of Reading and Mathematics between schools in a southern state using a four-period block schedule and schools using a non-block schedule in order to ascertain if the type of schedule has any impact on student achievement. Additionally, information pertaining to scheduling was collected …

A Relational Study Of Elementary Principals' Leadership Traits, Teacher Morale, And School Performance, Carla Jean Raines Evers

Dissertations

The purpose of the study was to determine if a significant relationship existed between elementary principals' leadership traits and teacher morale. The study sought to identify the impact of the principal-teacher relationship on school achievement as it relates to student performance on state standards as outlined in the Mississippi state academic frameworks and as measured using the Quality of the Distribution Index (QDI) on the Mississippi state end-of-grade test, Mississippi Curriculum Test, Second Edition (MCT2). The end-of-year assessments, collectively known as MCT2: Reading-Language Arts and Mathematics, administered to students in grades 3 through 8 in the spring of each school …

Factors Influencing International Students' Academic And Sociocultural Transition In An Increasingly Globalized Society, Chung-Hsien Hsu

Dissertations

This study is a mixed-method study. It consists of a quantitative study and a qualitative study. The quantitative study focused on international adult learners’ experiences of adaptation to American academic and social cultures. The qualitative study then investigated their experiences of cultural transition.

Based on the definition of globalized influences (Finger, 2005) and existing studies discussing the effects on globalized educational environments (Merriam & Young), factors related to globalized influences were selected and used to examine the extent to which these factors have affected international students’ adaptation to learning and life in the American university. Additionally, the other two variables, …

How Do Teacher Qualifications Impact Student Achievement In Relation To The Achievement Model Established By The Mississippi Department Of Education?, Timothy Darren Holland

Dissertations

The following study was conducted in a six-county geographical region and involved teachers from various high schools that taught classes which were involved in the subject area testing program. Each participant taught one of the four state-mandated subject area classes that are tested to determine achievement levels and accreditation ratings for each high school.

The focus of the study was to collect information from each teacher regarding the qualifications they held during the 2009-2010 school year and to compare those qualifications with the mean scale score for each teacher’s subject area classes. The researcher focused on five separate teacher qualifications …

Teacher Preparedness For Teaching And Assessing Depth Of Knowledge, Shelly Rankin Holmes

Dissertations

In the state of Mississippi, students in grades 3 through 8 are required to take an annual assessment, called MCT II, in Language Arts, Mathematics, and, more recently, Science. The results of this assessment may cause punitive consequences for each school and school district. State leaders have become increasingly concerned with student performance and accountability. Therefore, they have redesigned this assessment to accommodate a more challenging curriculum and to ensure alignment with national standards. The unanswered question is whether or not we have adequately prepared teachers for the increase in rigor and depth of knowledge for this assessment. A questionnaire …

Sensitive Detection Of High Explosives Using Electrogenerated Chemiluminescence, Suman Parajuli

Dissertations

The core of this dissertation lies in the search of analytical tools which can be used to detect and quantify the high explosives confiscated from suspects in transportation hubs and from soil and water bodies where these explosives pose a greater threat to public health and safety. High explosives, namely, hexamethylene triperoxide diamine (HMTD), triacetone triperoxide (TATP), trinitrotoluene (TNT), and pentaerythritol tetranitrate (PETN), were detected and quantified by electrochemical methods such as electrogenerated chemiluminescence (ECL) and cyclic voltammetry (CV).

Sensitive detection and quantification of HMTD, one commonly used explosive by terrorists, was presented first in this dissertation on the basis …

Modification And Evaluation Of Fuel Cell Membranes, Amol Prataprao Nalawade

Dissertations

The primary goals of this study were modification of existing Nafion^® membranes and characterization of newly developed hydrocarbon-based membranes for high temperature fuel cell applications. Various Nafion^®/silicate nanocomposites were formulated via in situ sol-gel reactions for tetraethylorthosilicate. Different silicate composition profiles generated across membrane cross-sections were investigated by EDAX/ESEM. Composite water uptake, proton conductivity and fuel cell performance were comparable to that of unmodified Nafion^®. Tafel analysis showed better electrode kinetics for composites having more silicate in the middle and less or no silicate at electrolyte-electrode interfaces. All composites showed reduced fuel cross-over and superior …

Microarray Data Mining And Gene Regulatory Network Analysis, Ying Li

Dissertations

The novel molecular biological technology, microarray, makes it feasible to obtain quantitative measurements of expression of thousands of genes present in a biological sample simultaneously. Genome-wide expression data generated from this technology are promising to uncover the implicit, previously unknown biological knowledge. In this study, several problems about microarray data mining techniques were investigated, including feature(gene) selection, classifier genes identification, generation of reference genetic interaction network for non-model organisms and gene regulatory network reconstruction using time-series gene expression data. The limitations of most of the existing computational models employed to infer gene regulatory network lie in that they either suffer …

Cloud Shadow Detection And Removal From Aerial Photo Mosaics Using Light Detection And Ranging (Lidar) Reflectance Images, Glover Eugene George

Dissertations

The process of creating aerial photo mosaics can be severely affected by clouds and the shadows they create. In the CZMIL project discussed in this work, the aerial survey aircraft flies below the clouds, but the shadows cast from clouds above the aircraft cause the resultant mosaic image to have sub-optimal results. Large intensity variations, caused both from the cloud shadow within a single image and the juxtaposition of areas of cloud shadow and no cloud shadow during the image stitching process, create an image that may not be as useful to the concerned research scientist. Ideally, we would like …

Is There A Correlation Between Differentiating Instruction And English Language Learner Achievement?, Melissa Monique Deangelo

Dissertations

Minority students and English language learners are underachieving. Schools with a culture of every student, every day, have the ability to break generational cycles and to change the future of these students that has been predicted by circumstances. This case study examined and analyzed the differentiated instructional practices and implementation at three elementary schools, and determined if there was a correlation between differentiated instruction and success of English language learners. More specifically, the purpose of this case study was to examine (a) the extent of the principles of differentiated instruction present in the classroom (b) differentiated instruction in response to …

Understanding The Relationship Between Students' Reading Achievement And Teachers' Self-Regulation Patterns In Grades K-3, Pamela Renee Allen

Dissertations

Previous findings on student self-regulation support the fact that students who are self-regulated achieve more in their academics, including students taught self-regulation interventions. However, there has been little research to establish how a teacher’s self-regulation affects a student’s academic success. Therefore, the purpose of this quantitative research study was to determine what specific teacher factors contribute to a teacher’s self-regulation score and a student’s reading achievement. The study consisted of 276 teachers in Grades K-3 in a large Alabama school district. Reading achievement test scores and the Self-Regulation Inventory (Casler, 2005a) were collected from respondents. A Pearson product-moment correlation established …

Photopolymerized Thiol-Ene Networks For Gas Barrier And Membrane Applications, Luke Kwisnek

Dissertations

Gas transport and free volume properties of photopolymerized thiol-ene networks for various applications are reported. For basic, commercially-available thiol-ene formulations, oxygen permeation was strictly dependent on the difference between T_test (room temperature for this work) and network T_g. Networks with T_g near T_test demonstrated the lowest values of permeability, diffusivity, and solubility. A robust, high-barrier network was selected for further modification. New networks with embedded functionality were formed using a two-step approach. Thio-Michael addition of a tetrathiol to monofunctional acrylates formed new functional thiol monomers. These functional thiols were combined with an isocyanurate-based triene and …