Physical Sciences and Mathematics Commons^™

Regulation Of A Dna-Compacting Plastid Nucleoid Protein, Steven William Adamson

Dissertations

DCP68, a DNA-compacting nucleoid protein, was further characterized in order to understand how plastid nucleoid proteins affect the structure and function of chloroplast DNA. Previously, DCP68 was identified as ferredoxin: sulfite reductase, an enzyme that participates in reductive sulfur assimilation and inhibits chloroplast DNA replication and transcription in vitro [1, 2]. In this study, the portion of SiR that was found to be present in soluble and plastid nucleoid-enriched fractions indicated that most SiR was stromal in Arabidopsis and soybean plants. Although SiR was detected in Arabidopsis chloroplast nucleoid-enriched fractions, the study of nucleoid dynamics proved to be difficult due …

Synthesis And Fundamental Characterization Of Nanoparticles And Their Clusters, Ke Du

Dissertations

Nanoparticles of gold derivatized with monolayers of thiocarboxylic acid ligands, core/shell nanoparticle composites of gold and silica, gold-glutathioneclusters, and titania nanoparticles were synthesized and their surface properties (extent of ligand coverage, net negative charge, and zeta potential) characterized by capillary electrophoresis as a function of pH, ionic strength, and dielectric constant for the first time. The hydrodynamic radii of thenanoparticles were determined by dynamic laser light scattering and used to calculate the net surface charge, extent of ligand coverage, and zeta potentials ofthe nanoparticles from electrophoresic mobilities. The ligand derivatized nanoparticles had similar hydrodynamic radius of about 20 nm which …

Retaining Information Technology Employees In Higher Education, Mary Holmes

Dissertations

The retention of qualified Information Technology (IT) employees is at an all time low within higher education institutions. IT personnel are essential for higher education institutions to effectively integrate technology into their educational programs. These IT employees contribute to their institution's teaching/learning mission, while simultaneously supporting complex and highly visible administrative operations. Yet, all previous research regarding IT employee retention issues had only been conducted within corporate settings.

To examine factors related to IT employees' retention within public higher education, an internet-based study was sent to IT employees in all four-year public universities throughout Michigan. The survey included questions within …

New Tests Of Univariate Symmetry Based On The Gini Mean Difference, Hend Ouda

Dissertations

Gini mean difference (GMD) was proposed as a measure of income inequality by Corrado Gini in 1912. Since then it has been widely applied - mostly in theeconomics, but also in statistical and social science research.

Four statistical tests of univariate symmetry are being proposed---all based on the comparison of variation below and above the median (known or estimated) measured by the GMD. These tests are applicable to the data from populations with median known and unknown, and each of them has its rank-basedcounterpart, so they can also be used for ordinal data.

A Monte Carlo simulation study was performed …

Investigation Of Oxy-Anion Legand Adsorption Onto Surfaces Of Iron Oxide And Bacteria In Groundwater Aquifers, Haile Mengistu

Dissertations

We have measured adsorption of dissolved phosphate onto synthetic hydrous ferric oxide (HFO), dissolved arsenate and chromate onto the cell membrane of a bacterium species, S. putrefaciens as a function of pH, ionic strength, and relative concentrations of the respective oxy-ligands. Our experimental data were used to constrain optimal values for surface complexation reactions involving dissolved oxi-ligands (phosphate, and chromate) and the HFO surface and the cell membrane of S. putrefaciens respectively according to the diffuse layer model.

Our results provide a more accurate fit to experimental measurements over a broader range of pH (3 - 12), ionic strength and …

The Viability Of Is Enhanced Knowledge Sharing In Mission-Critical Command And Control Centers, Sameh A. Sabet

Dissertations

Engineering processes such as the maintenance of mission-critical infrastructures are highly unpredictable processes that are vital for everyday life, as well as for national security goals. These processes are categorized as Emergent Knowledge Processes (EKP), organizational processes that are characterized by a changing set of actors, distributed knowledge bases, and emergent knowledge sharing activities where the process itself has no predetermined structure. The research described here utilizes the telecommunications network fault diagnosis process as a specific example of an EKP. The field site chosen for this research is a global undersea telecommunication network where nodes are staffed by trained personnel …

Selected Problems Of Inference On Branching Processes And Poisson Shock Model, Satrajit Roychoudhury

Dissertations

This dissertation explores the development of statistical methodology for some problems of branching processes and poisson shock model.

Branching process methods have become extremely popular in recent days. This dissertation mainly explores two fundamental inference problems of Galton-Watson processes. The first problem is concerned with statistical inference regarding the nature of the process. Two methodologies have been developed to develop a statistical test for the null hypothesis that the process is supercritical versus an alternative hypothesis that the process is non-supercritical. Another problem we investigate involves the estimation of the 'age' of a Galton-Watson Process. Three different methods are discussed …

Feasibility Of Superconductivity In Semiconductor Superlatices, Kenneth P. Walsh

Dissertations

The objective of this thesis is to explore superconductivity in semiconductor superlattices of alternating hole and electron layers. The feasibility of superconductivity in semiconductor superlattices is based on a model formulated by Harshrnan and Mills. In this model, a semiconductor superlattice forms the layered electron and hole reservoirs of high transition temperature (high-Tc) superconductors.

A GaAs-A1xGa1-xAs semiconductor structure is proposed which is predicted to superconduct at Tc = 2.0 K and may be analogous to the layered electronic structure of high-Tc superconductors. Formation of an alternating sequence of electron- and hole-populated quantum wells (an electron-hole superlattice) in a modulation-doped GaAs- …

The Effect Of Using A Video-Case Curriculum To Promote Preservice Teachers’ Development Of A Reflective Stance Towards Mathematics Teaching, Shari L. Stockero

Dissertations

This study investigates the effects of using a coherent video-case curriculum in a university methods course. In particular, three issues are addressed: (1) howthe use of a video-case curriculum affects the reflective stance of preservice teachers; (2) the extent to which a reflective stance developed while reflecting on other teachers' practice transfers to reflecting on one's own practice; and (3) how preservice teachers' reflective stance that is developed via sustained and focused reflection using a video-case curriculum compares to the reflective stance of peers who engaged in less sustained and focused reflection. Althoughvideo cases are increasingly being used in teacher …

Markov Chain Monte Carlo Methods For Regression Splines With A Penalized Acceptance Ratio, David Keith Stamps

Dissertations

An increasingly popular method for fitting complex models, particularly with a hierchical structure involvese the use of Markov Chain Monte Carlo simulation. Within a Bayesian framework, two major strategies are Gibbs sampling and Metropolis-Hastings methods. Recent research in the area of MCMC methods has witnessed the emergence of modeling efforts which permit the movement of the chain across models of varying dimensions. When properly constructed, such Markov chains converge to the joint posterior distribution of the parameters to be estimated, making Bayesian averaging an attractive option after convergence has occurred. With this transdimensional methodology, the Bayesian averaging process takes place …

Image Segmentation By Energy And Related Functional Minimization Methods, Eric Hudson Mason

Dissertations

Effective and efficient methods for partitioning a digital image into image segments, called ¿image segmentation,¿ have a wide range of applications that include pattern recognition, classification, editing, rendering, and compressed data for image search. In general, image segments are described by their geometry and similarity measures that identify them. For example, the well-known optimization model proposed and studied in depth by David Mumford and Jayant Shah is based on an L₂ total energy functional that consists of three terms that govern the geometry of the image segments, the image fidelity (or closeness to the observed image), and the prior …

A Distributed Hierarchical Energy-Efficient Scheme For Large Scale Mobile Wireless Ad Hoc Networks, Wasim El Hajj

Dissertations

In recent years, wireless networks have enjoyed tremendous development and popularity due to the technological advances of wireless radio devices. While interest in conventional wireless networks continues to evolve, new types of wireless networks, such as Mobile Ad Hoc Networks (MANET) and WirelessSensor Networks (WSN) are evolving fast and receiving much attention from academia, industry, and government.

Scalability and energy-efficiency present two of the most important challenges in Mobile Ad Hoc Networks. Scalability in MANETs can be defined as the capability of the network to provide an acceptable throughput when the network size increases. Energy-efficiency can be defined as using …

Detectable Coloring Of Graphs, Henry E. Escuadro

Dissertations

A basic problem in graph theory is to distinguish the vertices of a connected graph from one another in some manner. In this study, we investigate the problemof coloring the edges of a graph in a manner that distinguishes the vertices of the graph. The method we use combines many of the features of previously introduced methods.

Let G be a connected graph of order n ≥ 3 and let c : E (G ) [arrow right] {1,2,...,k } be a coloring of the edges of G (where adjacent edges may be colored the same). For each vertex …

Study Of Propagation And Detection Methods Of Terahertz Radiation For Spectroscopy And Imaging, Aparajita Bandyopadhyay

Dissertations

The applications of terahertz (THz, 1 THz is 1012 cycles per second or 300 pm in wavelength) radiation are rapidly expanding. In particular, THz imaging is emerging as a powerful technique to spatially map a wide variety of objects with spectral features which are present for many materials in THz region. Objects buried within dielectric structures can also be imaged due to the transparency of most dielectrics in this regime. Unfortunately, the image quality in such applications is inherently influenced by the scattering introduced by the sample inhomogeneities and by the presence of barriers that reduces both the transmitted power …

Linear And Log-Linear Models Based On Generalized Inverse Sampling Scheme, Soumi Lahiri

Dissertations

This dissertation explores the development of novel statistical techniques and the applications in modeling rare events using generalized inverse sampling scheme. The Poisson model can be used for independent frequency count data. Also negative binomial and negative multinomial (NMn) models are applicable when there is only one rare category in the population. Here, a new model, based on generalized inverse sampling scheme, is introduced to study several rare events simultaneouly. The generalized inverse sampling scheme is used to study several rare categories of a population. Samples are drawn until a predetermined number of the total of the rare events occur. …

Novel Characterization Of Materials Using Thz Spectroscopic Techniques, Amartya Sengupta

Dissertations

Significant scientific and technical challenges within the terahertz (THz) frequency regime have recently motivated an array of new research activities. This involves numerous applications of this region of the electromagnetic spectrum between approximately 100 GHz (3mm) and 3 THz (100 µm) for both spectroscopy and imaging purposes. THz time domain spectroscopy is unique in that the time domain waveforms are measured and the complex optical constants are deduced directly without resorting to the Kramers-Kronig Analysis.

In this work, THz spectroscopy has been used to characterize different types of materials. Materials investigated consisted of semiconductors, gate dielectric materials, high energetic materials …

Mathematical Problems Arising In Interfacial Electrohydrodynamics, Dmitri Tseluiko

Dissertations

In this work we consider the nonlinear stability of thin films in the presence of electric fields. We study a perfectly conducting thin film flow down an inclined plane in the presence of an electric field which is uniform in its undisturbed state, and normal to the plate at infinity. In addition, the effect of normal electric fields on films lying above, or hanging from, horizontal substrates is considered. Systematic asymptotic expansions are used to derive fully nonlinear long wave model equations for the scaled interface motion and corresponding flow fields. For the case of an inclined plane, higher order …

Facial Analysis In Video : Detection And Recognition, Peichung Shih

Dissertations

Biometric authentication systems automatically identify or verify individuals using physiological (e.g., face, fingerprint, hand geometry, retina scan) or behavioral (e.g., speaking pattern, signature, keystroke dynamics) characteristics. Among these biometrics, facial patterns have the major advantage of being the least intrusive. Automatic face recognition systems thus have great potential in a wide spectrum of application areas. Focusing on facial analysis, this dissertation presents a face detection method and numerous feature extraction methods for face recognition.

Concerning face detection, a video-based frontal face detection method has been developed using motion analysis and color information to derive field of interests, and distribution-based distance …

Interactions Of Ionic Liquids With Uranium And Its Implications On Biotransformation, Chengdong Zhang

Dissertations

Room temperature ionic liquids (ILs) are pure ionic compounds with melting points below 100°C, which have drawn great attention due to their many unique properties. They have been widely used in organic synthesis, analytical chemistry, and biochemistry. Although ionic liquids have been used to extract metals and radionuclides, there is no systematic study on the interactions of ILs with uranium and their effects on the biotransformation of uranium.

My research focused on: (1) the interactions between uranium and ionic liquids in aqueous solution; and (2) biotransformation of uranium in the presence of ILs. The interactions between three representative ionic liquids, …

Enhancing Web Marketing By Using Ontology, Xuan Zhou

Dissertations

The existence of the Web has a major impact on people's life styles. Online shopping, online banking, email, instant messenger services, search engines and bulletin boards have gradually become parts of our daily life. All kinds of information can be found on the Web. Web marketing is one of the ways to make use of online information. By extracting demographic information and interest information from the Web, marketing knowledge can be augmented by applying data mining algorithms. Therefore, this knowledge which connects customers to products can be used for marketing purposes and for targeting existing and potential customers. The Web …

Structural Auditing Methodologies For Controlled Terminologies, Hua Min

Dissertations

Several auditing methodologies for large controlled terminologies are developed. These are applied to the Unified Medical Language System XXXX and the National Cancer Institute Thesaurus (NCIT). Structural auditing methodologies are based on the structural aspects such as IS-A hierarchy relationships groups of concepts assigned to semantic types and groups of relationships defined for concepts. Structurally uniform groups of concepts tend to be semantically uniform. Structural auditing methodologies focus on concepts with unlikely or rare configuration. These concepts have a high likelihood for errors.

One of the methodologies is based on comparing hierarchical relationships between the META and SN, two major …

Gas Chromatography On Self Assembled Single Walled Carbon Nanotubes, Mahesh Kumar Karwa

Dissertations

Carbon nanotubes (CNTs) are nano-sized carbon-based sorbents, which have high surface area, large aspect ratio, can be self-assembled and are known to be stable at high temperatures. It is therefore conceivable that separation techniques, such as, gas chromatography (GC) can benefit from their unique properties and nano-scale interactions. Self-assembly, in-contrast to packing these materials in a tube, prevents them from agglomeration and thus facilitates in retaining their nano-characteristics. In this research, novel substrates, such as, steel tubings, on a scaled-up level have been explored for the self-assembly process of CNTs, for applications such as gas chromatography, where the CNTs served …

Investigations Of Poly[(Styrene-Co-P-Methylstyrene)-Risobutylene- R-(Styrene-Co-P-Methylstyrene)] And Poly[(Acrylic Acid)-5-Styrene-Jb-Is0butylene-5-Styrene-Jb-(Acrylic Acid)], James Grabill Kopchick

Dissertations

The pMe study was conducted to understand the morphological and physical property changes that occur as the ratio of pMe to styrene is increased, effectively increasing the aliphatic units. By the introduction of pMe, the interface region becomes more blended/compatible as the pMe migrates to the interface. These pMe groups are theorized in effect to create multiple ‘anchors’ to distribute the loads experienced at the interface more effectively creating a synergistic effect on the final properties of the copolymers. The primary goals of the pentablock study were the characterization of unique membranes as related to …

Testing Procedures For Group Sequential Clinical Trials With Multiple Survival Endpoints, Rebecca C. Scherzer

Dissertations

This research gives methods for sequential monitoring of survival data in clinical trials with multiple endpoints. We illustrate the use of marginal proportional hazards models and other survival models with various group sequential methods to test multiple survival endpoints at K interim analyses. To adjust for multiplicity at each interim analysis, we consider and extend methods developed by Tang and Geller (1999), Follmann, et al. (1994), and others. These methods are motivated, compared, and evaluated using survival data from a clinical study and using simulation studies.

New Estimators Of A Circular Median, Sauwanit Ratanaruamkarn

Dissertations

The specific properties of probability distributions on a circle require different definitions of several statistical concepts. For example, a median that can always be found for linear data not always exists on the circle. Several estimators of a circular median were proposed, lately by Otieno (2002), Otieno and Anderson - Cook (2003). Their work is, however, focused on the "preferred direction" which coincides with the median, mean and mode in the case of symmetric, unimodal distributions. This dissertation is focused on the estimators of a population median in a wider range of population distributions on a circle including distributions with …

Localization In Wireless Sensor Networks, Mark Terwilliger

Dissertations

With the proliferation of wireless sensor networks, providing location-aware technology and services to new applications have become important for developers. Localization is the problem of determining the positions of nodes in an ad hoc network. With the constrained resources of network sensors, providing robust localization services remains a fundamental research challenge facing the entire sensor network development community.

The initial localization problem that we addressed was to design and develop a working system that could locate equipment, such as a laptop or video projector. Ferret, the localization system developed, uses two different ranging techniques to help locate an object to …

Nilpotent Orbits On Infinitesimal Symmetric Spaces, Joseph A. Fox

Dissertations

Let G be a reductive linear algebraic group defined over an algebraically closed field k whose characteristic is good for G. Let [straight theta] be an involution defined on G, and let K be the subgroup of G consisting of elements fixed by [straight theta]. The differential of [straight theta], also denoted [straight theta], is an involution of the Lie algebra [Special characters omitted.] = Lie (G ), and it decomposes [Special characters omitted.] into +1- and -1-eigenspaces, [Special characters omitted.] and [Special characters omitted.] , respectively. The space [Special characters omitted.] identifies with the tangent space at the …

Synthetic Studies Of 1,10-Phenanthroline Derivatives As Novel Catalysis Ligands And Their Application In Transition Metals Catalyzed Reactions, Son Duc Tran

Dissertations

The preparation of 1,10-phenanthroline derivatives entailed ring opening reactions of 1,10-phenanthroline epoxide as a key transformation, affording novelbidentate nitrogen ligands with new stereogenic centers in the 5- and 6-position. This research was concerned with (i) the epoxidation of 1,10-phen, (ii) epoxide ring opening reactions, (iii) the formation of trans -5,6-disubstituted-1,10-phenanthroline metal complexes, and (iv) application of 1,10-phenanthroline derivatives in metal-catalyze reactions such as palladium-catalyzed allylic substitution and aminohalogenation reactions; Zinc-catalyzed direct aldolreaction, and acetophenone reduction; Nickel-catalyzed Michael addition reaction.

Text Mining With Exploitation Of User's Background Knowledge : Discovering Novel Association Rules From Text, Xin Chen

Dissertations

The goal of text mining is to find interesting and non-trivial patterns or knowledge from unstructured documents. Both objective and subjective measures have been proposed in the literature to evaluate the interestingness of discovered patterns. However, objective measures alone are insufficient because such measures do not consider knowledge and interests of the users. Subjective measures require explicit input of user expectations which is difficult or even impossible to obtain in text mining environments.

This study proposes a user-oriented text-mining framework and applies it to the problem of discovering novel association rules from documents. The developed system, uMining, consists of two …

Facial Feature Representation And Recognition, Chao-Fa Chuang

Dissertations

Facial expression provides an important behavioral measure for studies of emotion, cognitive processes, and social interaction. Facial expression representation and recognition have become a promising research area during recent years. Its applications include human-computer interfaces, human emotion analysis, and medical care and cure.

In this dissertation, the fundamental techniques will be first reviewed, and the developments of the novel algorithms and theorems will be presented later. The objective of the proposed algorithm is to provide a reliable, fast, and integrated procedure to recognize either seven prototypical, emotion-specified expressions (e.g., happy, neutral, angry, disgust, fear, sad, and surprise in JAFFE database) …