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 …

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 …

Monte Carlo Simulation Of Electron-Induced Air Fluorescence Utilizing Mobile Agents: A New Paradigm For Collaborative Scientific Simulation, Christopher Daniel Walker

Dissertations

A new paradigm for utilization of mobile agents in a modular architecture for scientific simulation is demonstrated through a case study involving Monte Carlo simulation of low energy electron interactions with molecular nitrogen gas. Design and development of Monte Carlo simulations for physical systems of moderate complexity can present a seemingly overwhelming endeavor. The researcher must possess or otherwise develop a thorough understanding the physical system, create mathematical and computational models of the physical system’s components, and forge a simulation utilizing those models. While there is no single route between a collection of physical concepts and a Monte Carlo simulation …

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, …

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) …

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 …

A Methodology To Develop A Communication Protocol For Visualizing Simulations In A Collaborative Virtual Reality Environment, Lacey Suzanne Duckworth

Dissertations

In the technology field, simulations and collaborative virtual reality environments (CVREs) are not generally combined because it is complicated to develop large scale simulations within CVREs. The complexity of combining these two technologies in order to form a better form of visualization stems from the lack of a methodology to help derive these scalable simulations. Simulations require very complex calculations that the CVRE cannot perform as it is overloaded in calculations for the maintenance and stability of the environment itself. Since the simulation cannot be held within the CVRE, the solution is to move the simulation external to the CVRE …

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 …

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 …

Face Recognition Using Multiple Features In Different Color Spaces, Zhiming Liu

Dissertations

Face recognition as a particular problem of pattern recognition has been attracting substantial attention from researchers in computer vision, pattern recognition, and machine learning. The recent Face Recognition Grand Challenge (FRGC) program reveals that uncontrolled illumination conditions pose grand challenges to face recognition performance. Most of the existing face recognition methods use gray-scale face images, which have been shown insufficient to tackle these challenges. To overcome this challenging problem in face recognition, this dissertation applies multiple features derived from the color images instead of the intensity images only.

First, this dissertation presents two face recognition methods, which operate in different …

Leach-Sm: A Protocol For Extending Wireless Sensor Network Lifetime By Management Of Spare Nodes, Bilal Abu Bakr

Dissertations

Operational lifetime of a wireless sensor network (WSN) depends on its energy resources. Significant improvement of WSN lifetime can be achieved by adding spare sensor nodes to WSN. Spares are ready to be switched on when any primary (a node that is not a spare) exhausts its energy. A spare replacing a primary becomes a primary itself.

The LEACH-SM protocol (Low-Energy Adaptive Clustering Hierarchy with Spare Management) proposed by us is a modification of the prominent LEACH protocol. LEACH extends WSN lifetime via rotation of cluster heads but allows for inefficiencies due to redundant sensing target coverage. There are two …

Debugging Support For Message-Passing Based Concurrent Software, Mohamed Medhat Elwakil

Dissertations

Today, multi-core processors are used in all computing aspects, including embedded systems such as mobile devices. In order for software programs to benefit from the transition to multi-core processors, the programs need to be concurrent.

Recent research shows that programs developed using the message-passing model can scale better than programs developed using the shared-memory model. However, the message-passing model is not widely adopted, partly, because of the lack of debugging tools. Debugging message-passing programs is very intricate due to their inherent nondeterministic behavior; even with the same input, a program may behave differently when executed multiple times. Bugs in message-passing …