Digital Commons Network^™

Gröbner Bases: A Natural Extension Of Gaussian Reduction And The Euclidean Algorithm (Abstract), Patrick Flinn

Kenneth C. Schraut Memorial Lectures

Gröbner bases can be used to answer fundamental questions concerning certain sets of polynomials. For example, when are two such sets equal? Given such a set and another polynomial, is this polynomial a member of that set? In this introduction to Gröbner bases, we motivate their salient features by considering the Euclidean algorithm and Gaussian row reduction of matrices from a slightly different point of view.

Existence, Uniqueness And Constructive Results For Delay Differential Equations, Paul W. Eloe, Youssef N. Raffoul, Christopher C. Tisdell

Mathematics Faculty Publications

Here, we investigate boundary-value problems (BVPs) for systems of second-order, ordinary, delay-differential equations. We introduce some differential inequalities such that all solutions (and their derivatives) to a certain family of BVPs satisfy some a priori bounds. The results are then applied, in conjunction with topological arguments, to prove the existence of solutions. We then apply earlier abstract theory of Petryshyn to formulate some constructive results under which solutions to BVPs for systems of second-order, ordinary, delay-differential equations are A-solvable and may be approximated via a Galerkin method. Finally, we provide some differential inequalities such that solutions to our equations are …

Sixth Kenneth C. Schraut Memorial Lecture (Poster), University Of Dayton. Department Of Mathematics

Kenneth C. Schraut Memorial Lectures

No abstract provided.

Stability Properties Of Linear Volterra Integrodifferential Equations With Nonlinear Perturbation, Muhammad Islam, Youssef Raffoul

Mathematics Faculty Publications

A Lyapunov functional is employed to obtain conditions that guarantee stability, uniform stability and uniform asymptotic stability of the zero solution of a scalar linear Volterra integrodifferential equation with nonlinear perturbation.

Boundedness And Stability In Nonlinear Delay Difference Equations Employing Fixed Point Theory, Muhammad Islam, Ernest Yankson

Mathematics Faculty Publications

In this paper we study stability and boundedness of the nonlinear difference equation

x(t+1)=a(t)x(t)+c(t)Δx(t−g(t))+q(x(t),x(t−g(t))).

In particular we study equi-boundedness of solutions and the stability of the zero solution of this equation. Fixed point theorems are used in the analysis.

2005 Program And Abstracts, University Of Dayton. Department Of Mathematics

Undergraduate Mathematics Day: Programs, Lectures, Promotional Materials

No abstract provided.

Shuffle Up And Deal; Should We Have Jokers Wild? (Abstract), Kristen Lampe

Undergraduate Mathematics Day: Programs, Lectures, Promotional Materials

From the Interactive Media Lab at the University of Florida to the Poker News blog to the Christian Science Monitor, everyone is talking about the rise in poker’s popularity.

2005 Undergraduate Mathematics Day Poster, University Of Dayton. Department Of Mathematics

Undergraduate Mathematics Day: Programs, Lectures, Promotional Materials

No abstract provided.

Sounding Rocket Redesign And Optimization For Payload Expansion And In Flight Telemetry Transmittal, Matthew Huffman

Electronic Theses and Dissertations

Due to renewed interest in the sub orbital rocket program of the Florida Space Authority and a surplus of Super Loki Sounding Rockets, an effort to improve the usefulness of this surplus is herein undertaken. Currently, the capacity of the payload compartment in the upper stage of the Super Loki system is very limited. A redesign of the upper stage will allow larger and more versatile payloads to be carried, assuming the appropriate design parameters are met. It has therefore been undertaken to create a design procedure that is comprehensive in scope in order to affect this redesign. This procedure …

A Framework To Model Complex Systems Via Distributed Simulation: A Case Study Of The Virtual Test Bed Simulation System Using The High Level Architecture, Jaebok Park

Electronic Theses and Dissertations

As the size, complexity, and functionality of systems we need to model and simulate con-tinue to increase, benefits such as interoperability and reusability enabled by distributed discrete-event simulation are becoming extremely important in many disciplines, not only military but also many engineering disciplines such as distributed manufacturing, supply chain management, and enterprise engineering, etc. In this dissertation we propose a distributed simulation framework for the development of modeling and the simulation of complex systems. The framework is based on the interoperability of a simulation system enabled by distributed simulation and the gateways which enable Com-mercial Off-the-Shelf (COTS) simulation packages to …

Implementation Strategies For Real-Time Traffic Safety Improvements On Urban Freeways, Jeremy Harvey Dilmore

Electronic Theses and Dissertations

This research evaluates Intelligent Transportation System (ITS) implementation strategies to improve the safety of a freeway once a potential of a crash is detected. Among these strategies are Variable Speed Limit (VSL) and ramp metering. VSL are ITS devices that are commonly used to calm traffic in an attempt to relieve congestion and enhance throughput. With proper use, VSL can be more cost effective than adding more lanes. In addition to maximizing the capacity of a roadway, a different aspect of VSL can be realized by the potential of improving traffic safety. Through the use of multiple microscopic traffic simulations, …

Stabilization And Tracking Of The Van Der Pol Oscillator, Xin Zhao

Electronic Theses and Dissertations

In this thesis, the stabilization and tracking problem of the Van der Pol oscillator is studied by using advanced control techniques. First, the linear state feedback and linear adaptive state feedback controllers for the stabilization problem are designed. Then, non-linear state feedback and output feedback controllers are proposed for the tracking problem with known parameters. Finally, a dynamic output feedback controller based on adaptive backstepping technique is introduced for the tracking problem when all parameters of the Van der Pol system are unknown.

Autonomous Repair Of Optical Character Recognition Data Through Simple Voting And Multi-Dimensional Indexing Techniques, Christopher Sprague

Electronic Theses and Dissertations

The three major optical character recognition (OCR) engines (ExperVision, Scansoft OCR, and Abby OCR) in use today are all capable of recognizing text at near perfect percentages. The remaining errors however have proven very difficult to identify within a single engine. Recent research has shown that a comparison between the errors of the three engines proved to have very little correlation, and thus, when used in conjunction, may be useful to increase accuracy of the final result. This document discusses the implementation and results of a simple voting system designed to prove the hypothesis and show a statistical improvement in …

Transmission Electron Microscopy Studies In Shape Memory Alloys, Madhavi Tiyyagura

Electronic Theses and Dissertations

In NiTi, a reversible thermoelastic martensitic transformation can be induced by temperature or stress between a cubic (B2) austenite phase and a monoclinic (B19') martensite phase. Ni-rich binary compositions are cubic at room temperature (requiring stress or cooling to transform to the monoclinic phase), while Ti-rich binary compositions are monoclinic at room temperature (requiring heating to transform to the cubic phase). The stress induced transformation results in the superelastic effect, while the thermally induced transformation is associated with strain recovery that results in the shape memory effect. Ternary elemental additions such as Fe can additionally introduce an intermediate rhombohedral (R) …

Numerical Modeling Of Dissimilatory Iron Reduction In Sediments At A Field Site, Chun-Wen Chen

Electronic Theses and Dissertations

The primary purpose of this study is to identify the 'universal' rate formulations with scaled-dependent parameters for the biological reduction of hematite. Three possible rate formulations were proposed to describe the bioreduction rate of hematite, and two kinds of simulation were conducted to validate the formulations and parameters with both batch and column experimental data: a reaction-based biogeochemical (batch) modeling with BIOGEOCHEM 1.0 and a reactive biogeochemical transport (column) modeling via HYDROGEOCHEM 4.0. Based on the results of simulations, only the dual Monod kinetic with inhibition rate formulation with respect to the concentrations of lactate, ßFeOOH, and Fe2+ under certain …

A Comparative Analysis Between Context-Based Reasoning (Cxbr) And Contextual Graphs (Cxgs)., Peterson Marthen Lorins

Electronic Theses and Dissertations

Context-based Reasoning (CxBR) and Contextual Graphs (CxGs) involve the modeling of human behavior in autonomous and decision-support situations in which optimal human decision-making is of utmost importance. Both formalisms use the notion of contexts to allow the implementation of intelligent agents equipped with a context sensitive knowledge base. However, CxBR uses a set of discrete contexts, implying that models created using CxBR operate within one context at a given time interval. CxGs use a continuous context-based representation for a given problem-solving scenario for decision-support processes. Both formalisms use contexts dynamically by continuously changing between necessary contexts as needed in appropriate …

In Situ Remediation Of Heavy Metal Contaminated Sediments Using Emulsified Zero-Valent Metal Particles, Kristen Marie Milum

Electronic Theses and Dissertations

Sediments can act as both a sink for pollutants and a source for aquatic contaminants. Natural and human disturbances of the sediments can release the contaminants to the overlying water where bottom dwelling, or benthic, organisms may be exposed through direct contact, ingestion of sediment particles, or uptake of dissolved contaminants present in the water. Dredging, the most common remediation technology for heavy metals, exacerbates this process. The in situ use of emulsified metal has been studied for its ability to pull heavy metals from aqueous solution and from saturated soils. It has proven successful in the laboratory with removal …

An Interactive Distributed Simulation Framework With Application To Wireless Networks And Intrusion Detection, Oleg Kachirski

Electronic Theses and Dissertations

In this dissertation, we describe the portable, open-source distributed simulation framework (WINDS) targeting simulations of wireless network infrastructures that we have developed. We present the simulation framework which uses modular architecture and apply the framework to studies of mobility pattern effects, routing and intrusion detection mechanisms in simulations of large-scale wireless ad hoc, infrastructure, and totally mobile networks. The distributed simulations within the framework execute seamlessly and transparently to the user on a symmetric multiprocessor cluster computer or a network of computers with no modifications to the code or user objects. A visual graphical interface precisely depicts simulation object states …

Three Dimensional Modeling Of Wekiva Springshed With Wash123d, Sandeep Paladagu

Electronic Theses and Dissertations

This thesis presents a three-dimensional groundwater modeling of Wekia springshed in central Florida using a numerical model, WASH123D. Springs have historically played an important role in Florida's history. The Wekiva River is a spring-fed system associated with about 19 springs connected to the Floridan aquifer. With increased urbanization and population growth in this region, there has been an increased strain on the water levels of Floridan aquifer which is a major source of potable water. Maintaining groundwater recharge to the aquifer is a key factor of the viability of the regional water supply as well as Wekiva ecosystem. Hence, the …

Evaluating The Effectiveness Of Training System Approaches For Highly Complex Flight Training, Maria Bauer

Electronic Theses and Dissertations

This research investigates the Training Effectiveness of a low-cost, PC-based training system when compared with two modes (motion and no motion) of a cab training system with large screen for various aviation flying tasks. While much research on this topic has been done in the past, advances in technology have significantly altered what is considered a "low-cost" "simulator." The technology advances have in effect increased the ability of a "low-cost" "simulator" to deliver desired experiences to the user. These "simulators" often are nothing more than PC training system, with only notional representations of the actual aircraft. This research considers the …

Numerical Study Of A High-Speed Miniature Centrifugal Compressor, Xiaoyi Li

Electronic Theses and Dissertations

A miniature centrifugal compressor is a key component of a reverse Brayton cycle cryogenic cooling system. The system is commonly used to generate a low cryogenic temperature environment for electronics to increase their efficiency, or generate, store and transport cryogenic liquids, such as liquid hydrogen and oxygen, where space limit is also an issue. Because of space limitation, the compressor is composed of a radial inlet guide vane, a radial impeller and an axial-direction diffuser (which reduces the radial size because of smaller diameter). As a result of reduction in size, in order to obtain the required static pressure ratio/rise, …

Creating Models Of Internet Background Traffic Suitable For Use In Evaluating Network Intrusion Detection Systems, Song Luo

Electronic Theses and Dissertations

This dissertation addresses Internet background traffic generation and network intrusion detection. It is organized in two parts. Part one introduces a method to model realistic Internet background traffic and demonstrates how the models are used both in a simulation environment and in a lab environment. Part two introduces two different NID (Network Intrusion Detection) techniques and evaluates them using the modeled background traffic. To demonstrate the approach we modeled five major application layer protocols: HTTP, FTP, SSH, SMTP and POP3. The model of each protocol includes an empirical probability distribution plus estimates of application-specific parameters. Due to the complexity of …

Achieving Cost-Effective Supply Chain Agility For The Semiconductor Industry, Mariah Jeffery

Electronic Theses and Dissertations

Supply chain agility has been receiving a lot of attention in recent literature as a way for organizations to become more responsive to change and improve customer service levels. However, agility is typically dealt with qualitatively, and organizations are usually unsure of the steps to take to improve their agility and the customer service level to target. This research studies supply chain agility based on a case study of Intel Corporation, a large semiconductor manufacturer. Here, agility is defined as the ability to satisfy customer demands by reacting effectively to changes in market stimuli. Reacting effectively does not mean reacting …

Analyzing The Community Structure Of Web-Like Networks: Models And Algorithms, Aurel Cami

Electronic Theses and Dissertations

This dissertation investigates the community structure of web-like networks (i.e., large, random, real-life networks such as the World Wide Web and the Internet). Recently, it has been shown that many such networks have a locally dense and globally sparse structure with certain small, dense subgraphs occurring much more frequently than they do in the classical Erdös-Rényi random graphs. This peculiarity--which is commonly referred to as community structure--has been observed in seemingly unrelated networks such as the Web, email networks, citation networks, biological networks, etc. The pervasiveness of this phenomenon has led many researchers to believe that such cohesive groups of …

Reaction Rates For The Dehalogenation Of Trichloroethylene Using Various Types Of Zero-Valent Iron, Neil Stewart

Electronic Theses and Dissertations

Remediation of trichloroethylene (TCE) and other chlorinated solvents is of great concern due to their toxicity and their persistence in the environment. Iron has been used extensively in the past decade as a subsurface reactive agent for the remediation of dense, nonaqueous-phase liquids (DNAPLs). Permeable reactive barrier walls (PRBW) have been installed at many sites around the country to treat contaminated plumes resulting from the presence of DNAPL pools. The use of zero-valent metals, such as iron, to effectively reductively dechlorinate DNAPLs has been employed as the reactive material in these PRBWs (Gillham et al., 1993). However, limited work has …

Part I : Isolation Of Dipentyl 2-(4-(Pentan-3-Yl) Phenyl) Malonate From Sanguisorba Officinalis Labill Part Ii: Synthesis Of A Novel Family Of Ethers Of Podocarpic Acid, Manjeera Yalavarty

Electronic Theses and Dissertations

The goal of part I of this thesis was to isolate pure anti cancer compounds from the Russian plant Sanguisorba officinalis. This plant was selected for investigation because it showed 100% activity against leukemia (L1210 mouse leukemia cells) during the preliminary screening of approximately 100 Russian plant extracts. This work has resulted in the isolation of novel compound 11 using traditional chromatography techniques. Compound 11 was characterized with spectroscopic techniques such as IR, 1H NMR, 13C NMR, DEPT, DQCOSY and MS. Compound 11 was assigned the structure dipentyl 2-(4-(pentan-3-yl) phenyl) malonate. The goal of part II of this thesis was …

Planning And Scheduling For Large-Scaledistributed Systems, Han Yu

Electronic Theses and Dissertations

Many applications require computing resources well beyond those available on any single system. Simulations of atomic and subatomic systems with application to material science, computations related to study of natural sciences, and computer-aided design are examples of applications that can benefit from the resource-rich environment provided by a large collection of autonomous systems interconnected by high-speed networks. To transform such a collection of systems into a user's virtual machine, we have to develop new algorithms for coordination, planning, scheduling, resource discovery, and other functions that can be automated. Then we can develop societal services based upon these algorithms, which hide …

Graph-Theoretic Approach To Modeling Propagation And Control Of Network Worms, Zoran Nikoloski

Electronic Theses and Dissertations

In today's network-dependent society, cyber attacks with network worms have become the predominant threat to confidentiality, integrity, and availability of network computing resources. Despite ongoing research efforts, there is still no comprehensive network-security solution aimed at controling large-scale worm propagation. The aim of this work is fivefold: (1) Developing an accurate combinatorial model of worm propagation that can facilitate the analysis of worm control strategies, (2) Building an accurate epidemiological model for the propagation of a worm employing local strategies, (3) Devising distributed architecture and algorithms for detection of worm scanning activities, (4) Designing effective control strategies against the worm, …

Super High-Speed Miniaturized Permanent Magnet Synchronous Motor, Liping Zheng

Electronic Theses and Dissertations

This dissertation is concerned with the design of permanent magnet synchronous motors (PMSM) to operate at super-high speed with high efficiency. The designed and fabricated PMSM was successfully tested to run upto 210,000 rpm The designed PMSM has 2000 W shaft output power at 200,000 rpm and at the cryogenic temperature of 77 K. The test results showed the motor to have an efficiency reaching above 92%. This achieved efficiency indicated a significant improvement compared to commercial motors with similar ratings. This dissertation first discusses the basic concept of electrical machines. After that, the modeling of PMSM for dynamic simulation …

Adapting The Modified Cam Clay Constitutive Model To The Computational Analysis Of Dense Granular Soils, Jose Arvelo

Electronic Theses and Dissertations

The computational constitutive Modified Cam Clay Model (MCCM) was developed at Cambridge to study the behavior of clays and has been proven to be effective. In this study, this model is extended to the case of dense sands to analyze the accuracy of the stress-strain behavior. This analysis is based on triaxial test data applied to remolded and compacted sand samples under drained conditions. The laboratory triaxial tests were performed by the Florida Department of Transportation to research the permeability effect in sandy soils compacted up to 95% of maximum unit weight at the optimum moisture content. Each soil sample …