Digital Commons Network^™

Stochastic Propagation Modeling And Early Detection Of Malicious Mobile Code, Xin Xu

Doctoral Dissertations

Epidemic models are commonly used to model the propagation of malicious mobile code like a computer virus or a worm. In this dissertation, we introduce stochastic techniques to describe the propagation behavior of malicious mobile code. We propose a stochastic infection-immunization (INIM) model based on the standard Susceptible-Infected-Removed (SIR) epidemic model, and we get an explicit solution of this model using probability generating function (pgf.). Our experiments simulate the propagation of malicious mobile code with immunization. The simulation results match the theoretical results of the model, which indicates that it is reliable to use INIM model to predict the propagation …

A Novel Computational Framework For Fast, Distributed Computing And Knowledge Integration For Microarray Gene Expression Data Analysis, Prerna Sethi

Doctoral Dissertations

The healthcare burden and suffering due to life-threatening diseases such as cancer would be significantly reduced by the design and refinement of computational interpretation of micro-molecular data collected by bioinformaticians. Rapid technological advancements in the field of microarray analysis, an important component in the design of in-silico molecular medicine methods, have generated enormous amounts of such data, a trend that has been increasing exponentially over the last few years. However, the analysis and handling of these data has become one of the major bottlenecks in the utilization of the technology. The rate of collection of these data has far surpassed …

Modeling And Simulation Of Value -At -Risk In The Financial Market Area, Xiangyin Zheng

Doctoral Dissertations

Value-at-Risk (VaR) is a statistical approach to measure market risk. It is widely used by banks, securities firms, commodity and energy merchants, and other trading organizations. The main focus of this research is measuring and analyzing market risk by modeling and simulation of Value-at-Risk for portfolios in the financial market area. The objectives are (1) predicting possible future loss for a financial portfolio from VaR measurement, and (2) identifying how the distributions of the risk factors affect the distribution of the portfolio. Results from (1) and (2) provide valuable information for portfolio optimization and risk management.

The model systems chosen …

Development Of A High Spatial Selectivity Tri-Polar Concentric Ring Electrode For Laplacian Electroencephalography (Leeg) System, Kanthaiah Koka

Doctoral Dissertations

Brain activity generates electrical potentials that are spatio-temporal in nature. Electroencephalography (EEG) is the least costly and most widely used non-invasive technique for diagnosing many brain problems. It has high temporal resolution but lacks high spatial resolution.

The surface Laplacian will enhance the spatial resolution of EEG as it performs the second spatial derivative of the surface potentials. In an attempt to increase the spatial selectivity, researchers introduced a bipolar electrode configuration using a five point finite difference method (FPM) and others applied a quasi-bipolar (tri-polar with two elements shorted) concentric electrode configuration. To further increase the spatial resolution, the …

A Numerical Method For Obtaining An Optimal Temperature Distribution In A Three-Dimensional Triple-Layered Skin Structure Embedded With Multi-Level Blood Vessels, Xingui Tang

Doctoral Dissertations

The research related to hyperthermia has stimulated a lot of interest in recent years because of its application in cancer treatment. When heating the tumor tissue, the crucial problem is keeping the temperature of the surrounding normal tissue below a certain threshold in order to avoid the damage to the normal tissue. Hence, it is important to obtain the temperature field of the entire region during the treatment. The objective of this dissertation is to develop a numerical method for obtaining an optimal temperature distribution in a 3D triple-layered skin structure embedded with multi-level blood vessels where the surface of …

Measuring Inequality: Statistical Inference Theory With Applications, Mihaela Paun

Doctoral Dissertations

In this dissertation we develop statistical inference for the Atkinson index, one of the measures of inequality used in studying economic inequality.

Specifically, we construct empirical estimators for the Atkinson index, both in the parametric and nonparametric case, and derive formulas for the asymptotic variances for the estimators. These statistics are used for testing hypothesis and constructing confidence intervals for the Atkinson index. We test the validity and the robustness of the asymptotic theory, by simulations (using R, a language and environment for statistical computing and graphics), in the case of one and two populations. In addition to proving asymptotic …

Investigation Of Copper(Ii) Complexes: I Copper(Ii) Complexes Of Tryptophan And Its Analogues As Postcolumn Interaction Components For Indirect Fluorescence Detection Of Amino-Containing Analytes Ii High-Performance Liquid Chromatographic Separation Of Copper(Ii) Azamacrocyclic Complexes, Xiaoxuan Shen

Doctoral Dissertations

The initial phase of this project investigates the use of copper(II) complexes of tryptophan and its analogues for indirect fluorescence detection in high-performance liquid chromatography. First, indirect photometric and fluorometric detection in high performance liquid chromatography (HPLC) is reviewed, giving the functional definition of indirect detection employed for this project, distinguishing different approaches to indirect photometric and fluorometric detection in HPLC, and explaining the basis of indirect fluorescence detection using copper(II) complexes of tryptophan and its analogues as postcolumn interaction components. Subsequent studies were conducted to develop and apply indirect HPLC detection for detecting specific mono-amino sugars, glucosamine, galactosamine, and …

Structural Analysis Of Cytokine Signaling Modulators, Cristina Ileana Silvescu

Doctoral Dissertations

The N-linked glycans attached to cytokine receptors modulate signal transduction by interacting with galectin-3 and generating a cell surface lattice. This opposes constitutive endocytosis and reduces the thresholds for cytokine signaling. The preferred ligands for galectin-3 are the poly-N-acetyl lactosaminylated tetra-antennary glycans which are synthesized by Mgat 5 and are present at high levels in tumor cells. A null mutation in Mgat 5 inhibits lattice formation and cancer progression in cells with an oncogenic background. GlcNAc feeding reestablishes lattice formation, cytokine signaling and tumorigenesis.

A MALDI-TOF analysis was employed to identify the N-glycans involved in modulating signal transduction in wild …

Improving Estimation Of Gross Primary Productivity Of Terrestrial Ecosystems, Qingyuan Zhang

Doctoral Dissertations

The MOderate Resolution Imaging Spectroradiometer (MODIS) provides an unprecedented opportunity to monitor and quantify seasonal changes of vegetation and phenology. MODIS has the potential to improve the estimation, which is based on the algorithms for the NOAA Advanced Very High Resolution Radiometer (AVHRR), of biophysical/biochemical variables of vegetation. My doctoral study improves estimation of gross primary productivity (GPP) through two aspects: first, my study improved the detection of vegetation phenology by distinguishing MODIS contaminated observations and contamination-free observations, and secondly, I inverted the fraction of absorbed photosynthetically active radiation (PAR) by chlorophyll using radiative transfer models and daily MODIS data. …

Soil Moisture Dynamics From Satellite Observations, Land Surface Modeling, And Field Data, Minha Choi

Doctoral Dissertations

Knowledge of soil moisture variability is essential to understand hydrologic processes at a range of scales. In this study, spatio-temporal variability of soil moisture and inter-comparison among different soil moisture products were analyzed. The variability patterns were well characterized by negative exponential fitting as function of observed sampling extent scale. The simple physical soil moisture dynamics model was identified as an alternative approach to characterize statistical soil moisture variability. The soil moisture variability was strongly related to physical properties including rainfall and topography.

Normal and log-normal distributions were recognized as the most efficient probability density functions to capture soil moisture …

Modeling Of Diffusional Creep And Stress Relaxation In Copper Grains During Manufacturing Of Microelectronic Integrated Circuits, Vasyl M. Grychanyuk

Doctoral Dissertations

The finite element technique was developed to study diffusional creep and stress relaxation in Cu grains with several atomic monolayers thick grain boundary region of enhanced diffusivity. The model was motivated by the need to study nanoscale back-end interconnect structures of microelectronic circuits. These structures have the length scale that does not conform to the assumptions of classical dimensional theories of diffusional creep.

Both diffusion and elasticity governing equations are considered in the coupled formulation of mass flow and stress analysis. Vacancy concentration field in the grains subjected to external load is coupled to stress field through diffusional creep strains. …

An Investigation Of Pre-Service Teachers' And Professional Mathematicians' Perceptions Of Mathematical Proof At The Secondary School Level, David M. Gray

Doctoral Dissertations

The National Council of Teachers of Mathematics [NCTM] states that by the time students graduate high school, they should learn to present "arguments consisting of logically rigorous deductions of conclusions from hypotheses" (NCTM, 2000, p. 56) in "written forms that would be acceptable to professional mathematicians" (NCTM, 2000, p. 58). Research studies indicate, however, that students and teachers have difficulty with many aspects of mathematical proof, including its nature and meaning. In addition, there appears to be a disconnect between school teachers' and university mathematicians' expectations for their respective students regarding mathematical proof. This study examined the perceptions of thirteen …

Characterization Of The Spatial And Temporal Variability In Pan-Arctic, Terrestrial Hydrology, Michael A. Rawlins

Doctoral Dissertations

Arctic hydrology represents an important component of the larger global climate system, and there are signs that significant water-cycle changes, involving complex feedbacks, have occurred. This dissertation explores the methods to estimate components of the arctic hydrological cycle, the numerous biases and uncertainties associated with the techniques, and suggestions for future research needs. The studies described here focus on quantitative models and methods for predicting the spatial and temporal variability in pan-Arctic hydrology.

This dissertation discusses pan-Arctic water budgets drawn from a hydrological model which is appropriate for applications across the terrestrial Arctic. Including effects from soil-water phase changes results …

Planar Algebras: A Category Theoretic Point Of View, Shamindra Kumar Ghosh

Doctoral Dissertations

We define Jones's planar algebra as a map of multicategories and construct a planar algebra starting from a 1-cell in a pivotal strict 2-category. We introduce the concept of affine representations of a planar algebra and prove some finiteness results for the affine representations of finite depth planar algebras. We also show that the radius of convergence of the dimension of an affine representation of the planar algebra associated to a finite depth subfactor is at least as big as the inverse-square of the modulus.

Cupolets: Chaotic Unstable Periodic Orbits Theory And Applications, Kourosh Zarringhalam

Doctoral Dissertations

Recent theoretical work suggests that periodic orbits of chaotic systems are a rich source of qualitative information about the dynamical system. The presence of unstable periodic orbits located densely on the attractor is a typical characteristic of chaotic systems. This abundance of unstable periodic orbits can be utilized in a wide variety of theoretical and practical applications [19]. In particular, chaotic communication techniques and methods of controlling chaos depend on this property of chaotic attractors [12, 13].

In the first part of this thesis, a control scheme for stabilizing the unstable periodic orbits of chaotic systems is presented and the …

Exploring Lesson Study As A Form Of Professional Development For Enriching Teacher Knowledge And Classroom Practices, Melissa K. Mitcheltree

Doctoral Dissertations

This study tracked the development of teacher knowledge through a professional development experience called lesson study. Lesson study is a Japanese professional development process in which a group of teachers develop a series of lessons using the following stages: planning lessons, teaching/observing the lessons, reflecting on lessons taught as well as sharing and discussing the lessons with their colleagues (Lewis, 2002). The aim of this study was to explore how the lesson study process influenced teacher knowledge of mathematics content and pedagogical content.

Study participants were four secondary mathematics teachers from a rural high school in the Northeast. All participants …

The Impact Of Sleep Quality And Duration On College Student Adjustment And Health, Robert L. Krenek Jr.

Doctoral Dissertations

College years are a time of change and transition that involves complex challenges in academic, social, personal/emotional, and institutional adjustment. Stress, anxiety, and tension are often associated with college transition and adjustment; stress and worry have been related to poor sleep quality. Studies have found that college students have more sleep problems than the general public. Research has shown that poor sleep has adverse effects on cognition, mood, and other physiological and psychological aspects of human functioning. Recent research has indicated that sleep quality may be more important than amount of sleep. Relationships have been found between sleep problems and …

Nanodot-Based Organic Memory Devices, Zhengchun Liu

Doctoral Dissertations

In this study, resistor-type, diode-type, and transistor-type organic memory devices were investigated, aiming at the low-cost plastic integrated circuit applications. A series of solution-processing techniques including spin-coating, inkjet printing, and self-assembly were employed to fabricate these devices.

The organic resistive memory device is based on a novel molecular complex film composed of tetracyanoquinodimethane (TCNQ) and a soluble methanofullerene derivative [6,6]-phenyl C61-butyric acid methyl ester (PCBM). It has an Al/molecules/Al sandwich structure. The molecular layer was formed by spin-coating technique instead of expensive vacuum deposition method. The current-voltage characteristics show that the device switches from the initial 'low' conduction state to …

Linking Multivariate Observations Of The Land Surface To Vegetation Properties And Ecosystem Processes, Stephen C. Hagen

Doctoral Dissertations

Remotely sensed images from satellites and aircrafts, as well as regional networks and monitoring stations such as eddy flux towers, are collecting large volumes of multivariate data that contain information about the land surface and ecosystem processes. To derive from these systems information and knowledge relevant to how the Earth system functions and how it is changing, we need tools that to filter and mine the large data streams currently being acquired at different spatial and temporal scales. A challenge for Earth System Science lies in accurately identifying and portraying the relationships between the measurements at the sensor and quantity …

Designing And Modeling Of A New Continuous Steelmaking Process, Jörg Peter

Doctoral Dissertations

"Continuous steel production has the potential to lower the cost of steelmaking as compared to current batch operations. However, experiences from past attempts to develop and commercialize continuous steelmaking processes show that there are several engineering hurdles to overcome. The objective of this research was the development of a fully continuous steelmaking process that would incorporate the lessons from past experiences, address the foreseen challenges, and meet the requirements to justify the possible replacement of the current EAF-LMF steelmaking route.

The design of the new process consists of five interconnected vessels. Preheated scrap would be continuously charged, melted, and superheated …

Evaluation Of The Effect Of Vehicle Performance On Consumer Satisfaction, Elizabeth A. Cudney

Doctoral Dissertations

"Value is the relationship of functionality or benefit to the cost of a product or service. Consumers appear to seek value, but not all consumers are alike in their needs and wants. Common characteristics that consumers desire in automobiles include a high level of value relative to the product's cost. Consumers measure vehicle performance in terms of twenty-three attributes such as roominess, ride, reliability, handling, brake pedal feel, visibility, interior noise, acceleration, etc. Problems arise when automakers try to translate these characteristics into vehicle performance specifications and capabilities.

Quality is an essential element for both the consumer and producer since …

Memory And Fragmentation In Dissociative Identity Disorder, Margaret Rose Barlow '96

Doctoral Dissertations

Dissociative identity disorder (DID), formerly called multiple personalities, is a condition in which aspects of experience and memory are separated from each other and from awareness. The current study adds to the literature in this area by utilizing a broad conceptualization of memory functioning in DID, combining ecologically valid memory tests with experimental paradigms, and examining shareability, switching, and integration. Eleven women with DID participated in a two-session experiment that included a variety of memory measures. Participants were given no instructions regarding switching among alters, but were later asked how often they had switched. They reported significantly higher levels of …

A Fe-Fd Hybrid Scheme For Solving Parabolic Two-Step Micro Heat Transport Equations In Irregularly Shaped Three Dimensional Double -Layered Thin Films Exposed To Ultrashort -Pulse Lasers, Brian R. Barron

Doctoral Dissertations

Multi-layer thin films are important components in many micro-electronic devices. These films are often used when a single film layer is insufficient to meet devices specifications. The continued reduction in component size has the side effect of increasing the thermal stress on these films and consequently the devices they comprise. Understanding the transfer of heat-energy at the micro-scale is important for thermal processing using a pulse-laser. Often, micro-voids may be found in processed devices. This is due to thermal expansion. Such defects may cause an amplification of neighboring defects resulting in severe damage and consequently the failure of the device. …

Availability Modeling And Evaluation On High Performance Cluster Computing Systems, Hertong Song

Doctoral Dissertations

Cluster computing has been attracting more and more attention from both the industrial and the academic world for its enormous computing power, cost effective, and scalability. Beowulf type cluster, for example, is a typical High Performance Computing (HPC) cluster system. Availability, as a key attribute of the system, needs to be considered at the system design stage and monitored at mission time. Moreover, system monitoring is a must to help identify the defects and ensure the system's availability requirement.

In this study, novel solutions which provide availability modeling, model evaluation, and data analysis as a single framework have been investigated. …

Microcapsule Biosensors Based On Competitive Binding And Fluorescence Resonance Energy Transfer Assays, Swetha Chinnayelka

Doctoral Dissertations

Fluorescent sensing systems offer the potential for minimally invasive monitoring with implantable devices, but they require carrier technologies that provide suitable immobilization, accessibility, and biocompatibility while maintaining adequate response characteristics. Towards the development of this goal, a general design of a biosensor with the capability of detecting different metabolites was investigated. The approach is based on the encapsulation of a competitive binding assay in microcapsules and monitoring the changes in fluorescence resonance energy transfer (FRET) in the presence of analyte. To experimentally demonstrate this type of sensing system, glucose was chosen as the model target analyte. The design, fabrication, and …

An Empirical Investigation To Detect The Presence Of Confirmation Bias In The Decision-Making Strategies Used By Litigants In Tax Court Memorandum Cases, Mary M. Anderson

Doctoral Dissertations

Normative decision theory describes the judgment and decision-making process as a cost/benefit analysis based upon maximum utility. One assumption of the theory is full rationality for choices made throughout the process. Due to bounded rationality, however, mental shortcuts become necessary. Use of these shortcuts does not necessarily diminish the quality of the decision. However, a suboptimal use of a heuristic results in a biased decision.

Kahneman and Tversky (1979) identify three basic heuristics: availability, representativeness, and anchoring and adjusting. One suboptimal use of the anchoring and adjusting heuristic, confirmation bias, is the unconscious search for and evaluation of information that …

Modeling, Design, And Validation Of Fluorescent Spherical Enzymatic Glucose Microsensors Using Nanoengineered Polyelectrolyte Coatings, Jonathan Quincy Brown

Doctoral Dissertations

In this dissertation, the modeling, design, and function of fluorescent spherical enzymatic microsensors for minimally-invasive diabetic monitoring are described. The devices reported herein are novel and their experimental construction and theoretical analysis have not been previously reported, thus laying the foundation for an intensive set of studies. These sensors are based on the encapsulation of an enzymatic fluorescent assay for glucose within hydrogel alginate microspheres with diameters on the order of tens of microns, which are of the appropriate size for intradermal implantation. A novel feature of these sensors is the use of multifunctional nanoengineered ultrathin multilayer polyelectrolyte coatings on …

Evaluating Online Trust Using Machine Learning Methods, Weihua Song

Doctoral Dissertations

Trust plays an important role in e-commerce, P2P networks, and information filtering. Current challenges in trust evaluations include: (1) fnding trustworthy recommenders, (2) aggregating heterogeneous trust recommendations of different trust standards based on correlated observations and different evaluation processes, and (3) managing efficiently large trust systems where users may be sparsely connected and have multiple local reputations. The purpose of this dissertation is to provide solutions to these three challenges by applying ordered depth-first search, neural network, and hidden Markov model techniques. It designs an opinion filtered recommendation trust model to derive personal trust from heterogeneous recommendations; develops a reputation …

Numerical Simulation Of Nanopulse Penetration Of Biological Matter Using The Z -Transform, Shengjun Su

Doctoral Dissertations

Short duration, fast rise time ultra-wide-band (UWB) electromagnetic pulses (“nanopulses”) are generated by numerous electronic devices in use today. Moreover, many novel technologies involving nanopulses are under development and expected to become widely used soon. Study of nanopulse bioeffects is needed to probe their useful range in possible biomedical and biotechnological applications, and to ensure human safety.

Based on the well-known dispersive properties of biological matter and their expression as a summation of terms corresponding to the main polarization mechanisms, the Cole-Cole expression is commonly employed to describe the frequency dependence of the dielectric properties of a tissue. Solving the …

Application Of Self -Assembled Ultrathin Film Coatings To Stabilize Enzyme Encapsulation And Activity In Alginate Microspheres, Rohit Srivastava

Doctoral Dissertations

Alginate-based hydrogels have been used for the encapsulation of a variety of materials, including enzymes, proteins, and cells for a wide range of applications from drug delivery to biosensors and bioreactors. However, due to the high porosity of the matrix, it has been increasingly difficult to retain macromolecules inside the alginate matrix, leading to loss in functionality over time. In an effort to improve the stability for long-term biosensor use, this work investigated layer-by-layer self-assembly as a potential technique to provide a diffusion barrier to an encapsulated macromolecule. Alginate microspheres (∼2–50μm radius) were fabricated using an emulsification technique, and were …