Physical Sciences and Mathematics Commons^™

Natural And Synthetic Viniferins Associated With The Grapevine Disease Young Vine Decline, David Michael Mcginnis

Chemistry & Biochemistry Theses & Dissertations

Grapevine disease has been thc subject of intense research amongst viticulturists over the last few decades, especially during the 1990's. There has been discoveries that suggest grapevine disease is commonly caused by fungal pathogens. One of the most common fungi that the vine may become infected by is known as Botrytis cinerea. B. cinerea is capable of attacking the grapevine which in turn will lead to bunch rot in the grape clusters. This disease has been researched in great detail during the past several years and is one of only few microorganisms that have actually been identified. Phaeoacremrmium chnlmydospnrum …

Development And Application Of A Gg-Irms Reductive Pyrolysis Reactor Interface For The Δ34S Determination Of Sulfur In Individual Organic Compounds, N. Deborah Hewlett

Chemistry & Biochemistry Theses & Dissertations

The incorporation of sulfur into sedimentary organic matter is an important aspect of organic carbon preservation. A better understanding of the sulfur cycle and the formation of organo-sulfur compounds are necessary if we are to better understand the interaction of biogeochemical cycles of C, N, O, H. and S. Currently, the determination of ³⁴S/³²S in organic matter is limited to bulk organic samples. The sulfur isotopic analysis of individual organo-sulfur compounds within the sediments should allow for a more complete understanding of the sulfur cycle and the processes which lead to sulfur incorporation into organic matter. This …

Fourier Transform Analysis Of Terahertz Radiation, Chikaodira N. Okpo

Electrical & Computer Engineering Theses & Dissertations

Advances in terahertz radiation (T-rays) technology have great promise in various technological areas ranging from medical technology, imaging technology and accelerator technology. At Thomas Jefferson Laboratory, the Free Electron Laser division (FEL) produces very powerful beam of laser light by accelerating electrons in bunches along a beamline. This laser light absorbs and releases energy at various wavelengths. The new FEL upgrade led to the production of very bright terahertz (THz) radiation with an average power of 1 00watts which is about 100,000 times brighter than those produced elsewhere. These T-rays have very significant applications in the Laboratory. The most significant …

Ozone Concentration In An Atmospheric Pressure Air Plasma Jet, Srinivas Reddy Suddala

Electrical & Computer Engineering Theses & Dissertations

A stable micro-plasma jet in air was generated from a direct current discharge between two molybdenum electrodes (0.25 mm thick) that were separated by an alumina insulator of the same thickness. The after-glow plasma jet was generated by blowing air through the space between the electrodes. A change from laminar to turbulent flow was observed at a gas flow rate of 140 ml/min. The length of the plasma jet increased with flow rate in the laminar mode to approximately 15 mm and decreased in the turbulent mode.

Increasing the gas flow rate up to 200 ml/min at a constant discharge …

Phytoplankton Development Within Tidal Freshwater Regions Of Two Virginia Rivers, Harold G. Marshall, Lubomira Burchardt

Virginia Journal of Science

Phytoplankton composition and the range of seasonal patterns of abundance are presented for the tidal freshwater regions in two Virginia rivers based on data accumulated monthly from 1986 through 1999. Diatoms dominated the flora during spring, summer, and fall, whereas, other taxonomic categories were more representative when the river flow rates decreased, allowing for a more stable water system and increased residency time within this tidal region during summer and early fall. This summer/fall period was associated with increased water temperatures, higher productivity rates and chlorophyll levels, increased total phytoplankton abundance and species diversity. The major components of the summer …

Opal: In Vivo Based Preservation Framework For Locating Lost Web Pages, Terry L. Harrison

Computer Science Theses & Dissertations

We present Opal, a framework for interactively locating missing web pages (http status code 404). Opal is an example of "in vivo" preservation: harnessing the collective behavior of web archives, commercial search engines, and research projects for the purpose of preservation. Opal servers learn from their experiences and are able to share their knowledge with other Opal servers using the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). Using cached copies that can be found on the web, Opal creates lexical signatures which are then used to search for similar versions of the web page. Using the OAI-PMH to facilitate …

Collaborative Caching For Efficient And Robust Certificate Authority Services In Mobile Ad-Hoc Networks, Laith Abdulaziz Al-Sulaiman

Computer Science Theses & Dissertations

Security in Mobile Ad-Hoc Network (MANET) is getting a lot of attention due to its inherent vulnerability to a wide spectrum of attacks. Threats exist in every layer of MANET stack, and different solutions have been adapted for each security problem. Additionally, availability is an important criterion in most MANET solutions, but many security frameworks did not consider it. Public-Key Infrastructure (PKI) is no exception, and its deployment in MANET needs major design and implementation modifications that can fit constraints unique to this environment. Our focus in this dissertation is to adapt and increase the availability of Certificate Authority (CA) …

Dream: A Theoretical Analysis, Xueying Qi

Computer Science Theses & Dissertations

A Mobile Ad-hoc Network (MANET, for short) is a collection of mobile nodes deployed in support of a short-lived special-purpose operation. Examples include search-and-rescue missions, law-enforcement, multimedia classrooms, and among many others. Unlike cellular or satellite networks, MANET do not rely on any form of pre-existing infrastructure. The mobility of nodes combined with the lack of infrastructure makes routing in MANET notoriously difficult. It was recently suggested that routing in MANET can use to advantage geographic information that the nodes may acquire either by endowing them with a GPS chip or simply by using known localization algorithms. Distance Routing Effect …

Mobility-Pattern Based Localization Update Algorithm For Mobile Wireless Sensor Networks, Mohammad Yacoub Al-Laho

Electrical & Computer Engineering Theses & Dissertations

In mobile wireless sensor networks, sensors move in the monitored area at any direction and speed. Unlike many other networking hosts, sensor nodes do not have global addresses. They are often identified by using a location-based addressing scheme. Therefore, it is important to have the knowledge of the sensor location indicating where the data came from. In this thesis, three localization update algorithms were designed, Specifically, a sensor movement is divided into three states: Pause, Linear, and Random. Each state adopts different localization update algorithm. Since complex movement involves different mobility patterns, a state transition model is developed to …

Modeling The Effects Of Physical And Biogeochemical Processes On Phytoplankton Species And Carbon Production In The Equatorial Pacific Ocean, Baris Salihoglu

OES Theses and Dissertations

The primary objective of this research is to investigate phytoplankton community response to variations in physical forcing and biological processes in the Cold Tongue region of the equatorial Pacific Ocean at 0°N, 140°W. This research objective was addressed using a one-dimensional multi-component lower trophic level ecosystem model that includes detailed algal physiology, such as spectrally-dependent photosynthetic processes and iron limitation on algal growth. The ecosystem model is forced by a one-year (1992) time series of spectrally-dependent light, temperature, and water column mixing obtained from a Tropical Atmosphere-Ocean (TAO) Array mooring. Autotrophic growth is represented by five algal groups, which have …

Investigation Of The Superconducting Properties Of Niobium Radio-Frequency Cavities, Gianluigi Ciovati

Physics Theses & Dissertations

Radio-frequency (rf) superconducting cavities are widely used to increase the energy of a charged particle beam in particle accelerators. The maximum gradients of cavities made of bulk niobium have constantly improved over the last ten years and they are approaching the theoretical limit of the material. Nevertheless, rf tests of niobium cavities are still showing some "anomalous" losses (so-called "Q-drop"), characterized by a marked increase of the surface resistance at high rf fields, in absence of field emission. A low temperature "in-situ" baking under ultra-high vacuum has been successfully applied by several laboratories to reduce those losses and …

Principal Component Regression For Construction Of Wing Weight Estimation Models, Humberto Rocha

Mathematics & Statistics Theses & Dissertations

The multivariate data fitting problem occurs frequently in many branches of science and engineering. It is very easy to fit a data set exactly by a mathematical model no matter how the data points are distributed. But building a response by using a limited number of poorly distributed data points is very unreliable, yet necessary in conceptual design process. This thesis documents the lessons learned from fitting the wing weight data of 41 subsonic transports by three types of interpolation methods---least polynomial interpolation, radial basis function interpolation, and Kriging interpolation. The objective of this thesis is to develop an automatic …

A Feature Specific Modular Approach For Pose And Illumination Invariant Face Recognition, Praveen Sankaran

Electrical & Computer Engineering Theses & Dissertations

A feature specific modular-PCA (Principal Component Analysis) approach on face images in multiple views for pose and illumination invariant face recognition is presented in this thesis. Principal components are extracted from different sub-modules of the image and are concatenated to make a single signature vector to represent a face region in a particular viewing angle. Additional principal components are extracted horn image regions representing key facial feature and are added as an extension of the signature vector. Feature specific modular-PCA approach is capable of recognizing faces in varying illumination conditions and facial expressions as the modular components represent the local …

Strategies For Analysis Of Unimodal And Multimodal Data For Simulation, Anshul Rai Sharma

Electrical & Computer Engineering Theses & Dissertations

The primary objective of this thesis is to provide strategies for analysis for data associated with simulation. Data analysis is an important part of the simulation process. Typically more stress is laid upon the development of the computer simulation while the data analysis takes a back seat. However, the accuracy of a simulation depends on the data driving it. In other words, any simulation is only as accurate as the input data fed into the simulation. Also, the output of simulation should be analyzed properly in order to validly estimate the performance of the system being simulated. The focus of …

Non-Linear And Linear Transformations Of Features For Robust Speech Recognition And Speaker Identification, Saurabh Prasad

Electrical & Computer Engineering Theses & Dissertations

Automatic speech recognizers perform poorly when training and test data are systematically different in terms of noise and channel characteristics. One manifestation of such differences is variations in the probability density functions (pdfs) between training and test features. Consequently, both automatic speech recognition and automatic speaker identification may be severely degraded. Previous attempts to mm1m1ze this problem include Cepstral Mean and Variance Normalization and transforming all speech features to a uni-variate Gaussian pdf. In this thesis, two techniques are presented for non-linearly scaling speech features to fit them to a target pdf - the first is based on the principles …

Interannual Variation Of Stratification In Lower Chesapeake Bay, Christopher S. Katzenmiller

OES Theses and Dissertations

Stratification in the water column can prove to be an important indicator to the state of the water column and ecosystem. The focus of this research is to evaluate trends in stratification in the Lower Chesapeake Bay. Detailed analysis was performed on a 14 year data set to study interannual variation in the region of study. Potential energy anomaly was used to quantify stratification. Potential energy anomaly is the amount of energy required to mix a water column. It is determined from the vertical density structure of density. Potential energy anomaly is the departure of potential energy from climate conditions. …

Circulation, Vol. 12, No. 1, Center For Coastal Physical Oceanography, Old Dominion University, Chester E. Grosch

CCPO Circulation

Spring 2005 issue of CCPO Circulation featuring article "Large Eddy Simulation of Langmuir Circulation in Shallow Water" by Dr. Chester Grosch

Correlation And Causes Of Fifth Order Cycles Within The Upper Cretaceous Eagle Formation, Bighorn Basin Of Wyoming, Kimberly Ann Johnson

OES Theses and Dissertations

Cyclic stratification was examined in the Upper Cretaceous (Santonian-Campanian) section (Eagle Formation) within the Bighorn Basin of Wyoming. Of particular concern was the 10³ to 10⁴ year band, which in marine settings has been attributed to orbital forcing (Milankovitch cyclicity). A series of 19 sections were measured through the Virgelle Member of the Eagle Formation. Most were measured on the “J”-shaped escarpment that constitutes the nose and north flank of the Thermopolis anticline. Several others were measured at sites up to 30 km to the northwest along paleo-shoreline. In the study, detailed thickness data of all sections and …

Lightweight Federation Of Non-Cooperating Digital Libraries, Rong Shi

Computer Science Theses & Dissertations

This dissertation studies the challenges and issues faced in federating heterogeneous digital libraries (DLs). The objective of this research is to demonstrate the feasibility of interoperability among non-cooperating DLs by presenting a lightweight, data driven approach, or Data Centered Interoperability (DCI). We build a Lightweight Federated Digital Library (LFDL) system to provide federated search service for existing digital libraries with no prior coordination.

We describe the motivation, architecture, design and implementation of the LFDL. We develop, deploy, and evaluate key services of the federation. The major difference to existing DL interoperability approaches is one where we do not insist on …

Programmable Process Flow Networks, Filip D. Cuckov

Electrical & Computer Engineering Theses & Dissertations

A model that introduces programmability to processes occurring in a cargo terminal simulation through the use of a process language is presented in this thesis. The model provides a means for a straight-forward definition, and redefinition of changing processes, their incorporation in the simulation architecture and efficient execution. The model was built to investigate a solution for transforming the cargo terminal simulation CPortS into a process-oriented simulation without hard-coded processes. The approach taken separates the system into an architecture and a set of processes which utilize and interact with the architecture's resources and infrastructure. The processes that take place within …

Creating Software [Sic] Environments On An M-Node Beowulf Cluster To Execute Discrete-Event Simulations, Jermaine Fitz-Gerald Headley

Electrical & Computer Engineering Theses & Dissertations

This thesis describes the development of a software tool that facilitates the creation of software environments that make a simulation tool execute k replications of an application program on several nodes of an M-node Beowulf cluster. It is assumed that each cluster-node consists of p processors. The p processors that are contained in the master cluster-node are termed master processors, and the p processors that are contained in a slave cluster-node are termed slave processors. The slave processors are used to execute the replications, while the master processors are dedicated to schedule the replications and process other housekeeping chores. For …

Statistical Analysis Of Longitudinal And Multivariate Discrete Data, Deepak Mav

Mathematics & Statistics Theses & Dissertations

Correlated multivariate Poisson and binary variables occur naturally in medical, biological and epidemiological longitudinal studies. Modeling and simulating such variables is difficult because the correlations are restricted by the marginal means via Fréchet bounds in a complicated way. In this dissertation we will first discuss partially specified models and methods for estimating the regression and correlation parameters. We derive the asymptotic distributions of these parameter estimates. Using simulations based on extensions of the algorithm due to Sim (1993, Journal of Statistical Computation and Simulation, 47, pp. 1–10), we study the performance of these estimates using infeasibility, coverage probabilities of the …

The Straggling Green's Function Method For Ion Transport, Steven Andrew Walker

Mathematics & Statistics Theses & Dissertations

For many years work has been conducted on developing a concise theory and method for HZE ion transport capable of being validated in the laboratory. Previous attempts have ignored dispersion and energy downshift associated with nuclear fragmentation and energy and range straggling. Here we present a Green's function approach to ion transport that incorporates these missing elements. This work forms the basis for a new version of GRNTRN, a Green's function transport code. Comparisons of GRNTRN predictions and laboratory results for an ⁵⁶Fe ion beam with average energy at the target of one GeV/amu or more are presented for …

Generalization Issues In Pattern Classification Applied To Speaker Identification, Mame C. Sall

Electrical & Computer Engineering Theses & Dissertations

This thesis is an extension of previous work on speaker identification, but with a primary focus on the generalization performance of patterns classifiers for speaker identification. The goal for all pattern classifiers is to generalize to new data, not just perform well on the training data set. The error on the training data is typically a biased estimate of the generalization error. The training set error tends to be smaller than the generalization error if the model is selected such that it minimizes the training error. Therefore, the training error alone should not be used as a good predictor of …

Rapid Prototyping For The Design Of Virtual Worlds, Prabhu V. Krishnan

Electrical & Computer Engineering Theses & Dissertations

Development of Virtual Reality (VR) applications is challenging where application developers are required to have expertise in the target VR technologies along with the problem domain expertise. New VR technologies impose a significant learning curve to even the most experienced VR developer. The proposed solution relies on synthesis to automate the migration of a VR application to a new unfamiliar VR platform/technology. To solve the problem, the Common Scene Definition Framework (CSDF) was developed, that serves as a superset/model representation of the target virtual world. Input modules were developed to populate the framework with the capabilities of the virtual world …

Applying A Simulation-Based Real-Time Decision Making Method To Mass Casualty Scenarios In Hospital Emergency Departments, Fatemah Al-Douli

Electrical & Computer Engineering Theses & Dissertations

The high possibility of having a mass casualty incident compels hospitals to plan ahead in order to sufficiently provide the healthcare needed to as many casualty victims as possible. The Emergency Rooms (ER) are usually hospitals' main entrance for many casualties. Therefore, the ER in the Children's Hospital of the King's Daughters (CHKD) was selected as the system to be examined. The ER in CHKD, the only specialized pediatric ER in the region, already struggles to handle very high patient arrival rates. Consequently, it is expected that treating a large number of patients surviving within a very short period of …

Image Compression By Vector Quantization Of Dct Coefficients Using A Self-Organizing Neural Network, Kirankumar Boyapati

Electrical & Computer Engineering Theses & Dissertations

Image compression is used to remove different types of redundancies and irrelevant information in an image so that the space required for storing the image is minimized. Conventional transform based techniques remove the redundancies between adjacent pixels and irrelevant information in the image but fail to remove the redundancies between different parts of the image. There are techniques like vector quantization, which take care of the redundant information in different parts of the image, but fail to remove the irrelevant information in the image. In this thesis a new technique for lossy digital image compression is proposed which is a …

Clustering And Hybrid Routing In Mobile Ad Hoc Networks, Lan Wang

Computer Science Theses & Dissertations

This dissertation focuses on clustering and hybrid routing in Mobile Ad Hoc Networks (MANET). Specifically, we study two different network-layer virtual infrastructures proposed for MANET: the explicit cluster infrastructure and the implicit zone infrastructure. In the first part of the dissertation, we propose a novel clustering scheme based on a number of properties of diameter-2 graphs to provide a general-purpose virtual infrastructure for MANET. Compared to virtual infrastructures with central nodes, our virtual infrastructure is more symmetric and stable, but still light-weight. In our clustering scheme, cluster initialization naturally blends into cluster maintenance, showing the unity between these two operations. …

The Role Of Feeding Behavior In Sustaining Copepod Populations In The Tropical Ocean, J. D. Wiggert, A. G. E. Haskell, G.-A. Paffenhofer, E. E. Hofmann, J. M. Klinck

CCPO Publications

A fundamental question regarding marine copepods is how the many species coexist and persist in the oligotrophic environment (i.e. Hutchinson’s paradox). This question is addressed with a stochastic, object-oriented Lagrangian model that explicitly simulates the distinct foraging behaviors of three prominent tropical species: Clausocalanus furcatus, Paracalanus aculeatus and Oithona plumifera. The model also individually tracks all prey cells. Each particle’s motion combines sinking, turbulent diffusion and active swimming when applicable. The model successfully simulates observed size partitioned carbon uptake rates. Based on the model results, the wide-ranging translational ambit employed by C. furcatus is best suited for the acquisition …

High-Energy Effective Action From Scattering Of Qcd Shock Waves, Ian Balitsky

Physics Faculty Publications

At high energies, the relevant degrees of freedom are Wilson lines—infinite gauge links ordered along straight lines collinear to the velocities of colliding particles. The effective action for these Wilson lines is determined by the scattering of QCD shock waves. I develop the symmetric expansion of the effective action in powers of strength of one of the shock waves and calculate the leading term of the series. The corresponding first-order effective action, symmetric with respect to projectile and target, includes both up and down fan diagrams and pomeron loops.