Physical Sciences and Mathematics Commons^™

Extensions Of Snomed Taxonomy Abstraction Networks Supporting Auditing And Complexity Analysis, Duo Wei

Dissertations

The Systematized Nomenclature of Medicine – Clinical Terms (SNOMED CT) has been widely used as a standard terminology in various biomedical domains. The enhancement of the quality of SNOMED contributes to the improvement of the medical systems that it supports.

In previous work, the Structural Analysis of Biomedical Ontologies Center (SABOC) team has defined the partial-area taxonomy, a hierarchical abstraction network consisting of units called partial-areas. Each partial-area comprises a set of SNOMED concepts exhibiting a particular relationship structure and being distinguished by a unique root concept. In this dissertation, some extensions and applications of the taxonomy framework are considered. …

Security Systems Based On Gaussian Integers : Analysis Of Basic Operations And Time Complexity Of Secret Transformations, Aleksey Koval

Dissertations

Many security algorithms currently in use rely heavily on integer arithmetic modulo prime numbers. Gaussian integers can be used with most security algorithms that are formulated for real integers. The aim of this work is to study the benefits of common security protocols with Gaussian integers. Although the main contribution of this work is to analyze and improve the application of Gaussian integers for various public key (PK) algorithms, Gaussian integers were studied in the context of image watermarking as well.

The significant benefits of the application of Gaussian integers become apparent when they are used with Discrete Logarithm Problem …

The Effects Of Periodic And Non-Periodic Inputs On The Dynamics Of A Medial Entorhinal Cortex Layer Ii Stellate Cell Model, Dongwook Kim

Dissertations

Various neuron types exhibit sub-threshold and firing frequency resonance in which the sub-threshold membrane potential or firing frequency responses to periodic inputs peak at a preferred frequency (or frequencies). Previous experimental work has shown that medial entorhinal cortex layer II stellate cells (SCs) exhibit sub-threshold and firing frequency resonance in the theta frequency band (4 - 10 Hz). In this thesis we seek to understand the biophysical and dynamic mechanism underlying these phenomena and how they are related. We studied the effects of sinusoidal current and synaptic conductance inputs at various frequencies, with and without noise, on the supra-threshold dynamics …

Energy Propagation In Jammed Granular Matter, Xiaoni Fang

Dissertations

The systems built from dense granular materials are very important due to their relevance to a number of technological and other fields. However, they are difficult to study in particular due to a lack of accurate continuum description. In this work, studies on these systems are presented using discrete element simulations that model the granular particles as soft, elastic, and frictional disks which interact when in contact. These simulations are used for the purpose of analyzing a few granular systems with the main emphasis on understanding phenomena of energy and force propagation.

Analysis of energy propagation in a two-dimensional disordered …

Investigation On Advanced Image Search Techniques, Abhishek Verma

Dissertations

Content-based image search for retrieval of images based on the similarity in their visual contents, such as color, texture, and shape, to a query image is an active research area due to its broad applications. Color, for example, provides powerful information for image search and classification. This dissertation investigates advanced image search techniques and presents new color descriptors for image search and classification and robust image enhancement and segmentation methods for iris recognition.

First, several new color descriptors have been developed for color image search. Specifically, a new oRGB-SIFT descriptor, which integrates the oRGB color space and the Scale-Invariant Feature …

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 …

Enhanced Membrane Distillation : Analytical And Deionization Applications, Ken Gethard

Dissertations

Membrane distillation (MD) is a newer technology that is being investigated for applications such as seawater desalination and concentration of fruit and sucrose solutions. The major advantage of MD over traditional thermal distillation is that it requires a substantially lower thermal energy requirement to power the process. This allows low grade energy sources such as waste heat or solar energy to be used with MD. Compared to concentration processes such as reversed osmosis or ion-exchange, MD does not require specialized equipment, high electrical consumption, the use of strong acids and bases nor does it generate hazardous waste as a by-product. …

Anti-Solvent Precipitation And Subsequent Film Formation Of Hydrophobic Drugs For Drug Delivery, Xiangxin Meng

Dissertations

It is estimated that about forty percent of the drug molecules being developed by the pharmaceutical industry are hydrophobic in nature, leading to poor water solubility and bioavailability in the gastrointestinal tract. Dissolution is a limiting factor in their in vivo performance, and increasing their dissolution rate is a major challenge. It has been proven that the dissolution rate is directly proportional to the specific surface area, which can be effectively increased by reducing the particle size. Therefore, considerable efforts have gone into developing reliable and efficient methods for the manufacture of fine particles. Particle size reduction technologies such as …

Confidence Bands For Survival Functions Under Semiparametric Random Censorship Models, Peixin Zhang

Dissertations

In medical reports point estimates and pointwise confidence intervals of parameters are usually displayed. When the parameter is a survival function, however, the approach of joining the upper end points of individual interval estimates obtained at several points and likewise for the lower end points would not produce bands that include the entire survival curve with a given confidence. Simultaneous confidence bands, which allow confidence statements to be valid for the entire survival curve,would be more meaningful

This dissertation focuses on a novel method of developing one-sample confidence bands for survival functions from right censored data. The approach is model- …

Analysis Of Mueller Matrices Of Metamaterials And Multiferroics, Paul D. Rogers

Dissertations

The optical spectra of complex materials such as magnetic-dielectric media, magnetoelectric and multiferroic crystals, materials with intrinsic chirality, and metamaterials are studied. These media are important both for: (i) their interesting optical effects, such as Negative Index of Refraction (NIR) and impedance matching; and (ii) possible device applications such as switching devices and anti-reflection coatings. Proper characterization of complex materials requires advanced spectroscopic approaches and the development of theoretical models for data analysis. Berreman’s 4´4 matrix formalism is used to derive forward models for the optical spectra of Reflectivity, Transmission, Rotating Analyzer Ellipsometry (RAE), and Mueller Matrices (MM). The forward …

Development Of Advanced Algorithms To Detect, Characterize And Forecast Solar Activities, Yuan Yuan

Dissertations

Study of the solar activity is an important part of space weather research. It is facing serious challenges because of large data volume, which requires application of state-of-the-art machine learning and computer vision techniques. This dissertation targets at two essential aspects in space weather research: automatic feature detection and forecasting of eruptive events.

Feature detection includes solar filament detection and solar fibril tracing. A solar filament consists of a mass of gas suspended over the chromosphere by magnetic fields and seen as a dark, ribbon-shaped feature on the bright solar disk in Hα (Hydrogen-alpha) full-disk solar images. In this dissertation, …

High-Order Adaptive Methods For Computing Invariant Manifolds Of Maps, Jacek K. Wrobel

Dissertations

The author presents efficient and accurate numerical methods for computing invariant manifolds of maps which arise in the study of dynamical systems. In order to decrease the number of points needed to compute a given curve/surface, he proposes using higher-order interpolation/approximation techniques from geometric modeling. He uses B´ezier curves/triangles, fundamental objects in curve/surface design, to create adaptive methods. The methods are based on tolerance conditions derived from properties of B´ezier curves/triangles. The author develops and tests the methods for an ordinary parametric curve; then he adapts these methods to invariant manifolds of planar maps. Next, he develops and tests the …

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 …

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) …

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 …

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 …

Synthesis Towards Synthetic Adenosine Receptor, Rajni Gupta

Theses

Adenosine is a biologically important molecule as it acts as local modulator with cytoprotective function in the body. Adenosine accumulates in the extracellular space in response to metabolic stress and cell damage, and elevations in extracellular adenosine level are found in conditions like myocardial ischemia, hypoxia, inflammation and trauma. Its abnormal concentration therefore could be a marker of many diseases. Therefore determining its concentration can help understand the physiological state of the body. However its selective detection by synthetic receptors is not possible till date.

Efforts have been made here to design molecular tweezer for adenosine. Multistep synthesis was done …

Dynamic-Parinet (D-Parinet) : Indexing Present And Future Trajectories In Networks, Mou Nandi

Theses

While indexing historical trajectories is a hot topic in the field of moving objects (MO) databases for many years, only a few of them consider that the objects movements are constrained. DYNAMIC-PARINET (D-PATINET) is designed for capturing of trajectory data flow in multiple discrete small time interval efficiently and to predict a MO’s movement or the underlying network state at a future time.

The cornerstone of D-PARINET is PARINET, an efficient index for historical trajectory data. The structure of PARINET is based on a combination of graph partitioning and a set of composite B+-tree local indexes tuned for a given …

Thermochemistry And Bond Energies Of Acetohydrazide, Amides And Cyclic Alkyl Ethers, Sumit Charaya

Theses

Structure, thermochemical properties, bond energies and internal rotation potentials of Acetic Acid Hydrazide (CH₃CONHNH₂), Acetamide (CH₃CONH₂) and N-methyl Acetamide (CH3CONHCH3) and their radicals corresponding to loss of hydrogen atom have been studied. Gas phase standard enthalpies of formation and bond energies were calculated using the DFT methods B3LYP/6-31G(d,p), B3LYP/6-31G(2d,2p) and the composite CBS-QB3 methods employing a series of work reactions to further improve accuracy of the ΔH_f°(298K). Molecular structures, vibration frequencies and internal rotor potentials were calculated at DFT level. The enthalpies of the parent molecules CH₃-C=ONHNH_{2 …}

Fast Program For Sequence Alignment Using Partition Function Posterior Probabilities, Meera Prasad

Theses

The key requirements of a good sequence alignment tool are high accuracy and fast execution. The existing Probalign program is a highly accurate tool for sequence alignment of both proteins and nucleotides. However, the time for execution is fairly high. The focus is therefore, to reduce the running time of the existing version of Probalign, maintaining its current accuracy level.

The thesis conducts a detail analysis of the performance of Probalign to bring down the running time of the existing code. A modified version of Probalign, Version 1.4 is released. A new program for sequence alignment with faster computation is …

Ranking Single Nucleotide Polymorphisms With Support Vector Regression In Continuous Phenotypes, Seif Shahidain

Theses

Support vector machines (SVM) have been used to improve the ranking of single nucleotide polymorphisms (SNPs) over traditional chi-square tests in disease case studies [2]. In this investigation, ranking SNPs with support vector regression (SVR) was compared to the Wald test in predicting continuous phenotypes. SVR-ranked SNPs consistently outperformed the Wald test-ranked SNPs to provide a more accurate prediction of the phenotype with fewer SNPs across several methods of prediction.

G-Factors For Ternary Crystals Of Groups Iii And V, Liviu Mateescu

Theses

The objective of this thesis is to present a method of calculating the g-factors of ternary crystals of III-V group elements.

There is an increasing interest in knowing the magnetic behavior of different semiconductor materials, due to advances in the domain of spintronics. The g-factors were calculated for the conduction electrons, since they have the greatest contribution to the magnetic properties of the crystal. The thesis presented here proposes a method to calculate the magnetic g-factor of whole families of crystals made of three elements, of the form A_1-xB_xC, for eleven values, x ε {0, 0.1, …

A Molecular Dynamics Simulation Based Principal Component Analysis Framework For Computation Of Multi-Scale Modeling Of Protein And Its Interaction With Solvent, Tao Wu

Dissertations

This dissertation presents a new computational framework for calculating the normal modes and interactions of proteins, macromolecular assemblies and surrounding solvents. The framework employs a combination of molecular dynamics simulation (MD) and principal component analysis (PCA). It enables the capture and visualization of the molecules' normal modes and interactions over time scales that are computationally challenging. It also provides a starting point for experimental and further computational studies of protein conformational changes.

A protein's function is sometimes linked to its conformational flexibility. Normal mode analysis (NMA) and various extensions of it have provided insights into the conformational fluctuations associated with …

Modeling Of Magnetic Field Driven Simultaneous Assembly, Rene David Rivero

Dissertations

The Magnetic Field Driven Simultaneous Assembly (MFDSA) is a method that offers a non-statistical and deterministic solution to the problem of assembly via batch processing; a hybrid of serial and parallel processing. The technique requires the use of electromagnets as well as soft and hard magnetic materials that are applied to devices and recesses respectively. The MFDSA approach offers the ability to check and correct errors in real-time and is capable of scalable, versatile, and high-yield integration.

Devices, coated with a layer of soft magnetic material, are moved from initial to final positions along predetermined pathways through the action of …

Radio-Derived Three-Dimensional Structure Of A Solar Active Region, Samuel D. Tun

Dissertations

Solar active regions are the source of the most violent events observed on the Sun, some of which have a direct impact to modern civilization. Efforts to understand and predict such events require determination of the three-dimensional distributions of density, temperature, and magnetic fields above such active regions. This thesis presents the structure of the solar atmosphere above active region AR 10923, observed on 2006 Nov 10, as deduced from multi-wavelength studies including combined microwave observations from the Very Large Array (VLA) and the Owens Valley Solar Array (OVSA). The VLA observations provide excellent image quality at a few widely …