Physical Sciences and Mathematics Commons^™

Secure And Efficient Data Extraction For Ubiquitous Computing Applications, Chiu Chiang Tan

Dissertations, Theses, and Masters Projects

Ubiquitous computing creates a world where computers have blended seamlessly into our physical environment. In this world, a "computer" is no longer a monitor-and-keyboard setup, but everyday objects such as our clothing and furniture. Unlike current computer systems, most ubiquitous computing systems are built using small, embedded devices with limited computational, storage and communication abilities. A common requirement for many ubiquitous computing applications is to utilize the data from these small devices to perform more complex tasks. For critical applications such as healthcare or medical related applications, there is a need to ensure that only authorized users have timely access …

Comparison Of Full-Wave And Ray-Tracing Analysis Of Mode Conversion In Plasmas, Yanli Xiao

Dissertations, Theses, and Masters Projects

This dissertation reports on the first direct comparison between the results of ray-based and full-wave calculations for mode conversion in plasma. This study was motivated by the modular method originally developed by Ye and Kaufman to treat a magnetosonic wave crossing a cold minority-ion gyroresonance layer. We start with the cold plasma fluid model and introduce a system of evolution equations for electrons and two ion species: deuterium and hydrogen. We first study this system of equations for uniform plasma by Fourier methods, which gives the dispersion relations. We discuss how the traditional approach---which eliminates all other dynamical variables in …

Spatial And Temporal Patterns In Erosional And Depositional Processes: Physical And Biological Controls In The York River, Chesapeake Bay, Virginia, Cielomar Rodríguez-Calderon

Dissertations, Theses, and Masters Projects

No abstract provided.

Habitat Complexity And Habitat Function Of Native (Crassostrea Virginica) And Non-Native (C. Ariakensis) Oysters In The Chesapeake Bay Region, Heather D. Harwell

Dissertations, Theses, and Masters Projects

Complex oyster reefs created by the Eastern oyster, Crassostrea virginica, though once prominent features of the Chesapeake Bay region, have become relatively scarce in comparison to historic descriptions. This decline, caused by a combination of overfishing, disease, habitat destruction and pollution, this decline continues despite substantial restoration efforts that have spanned decades. In response to this decline, the states of Virginia and Maryland considered the intentional introduction of the non-native Suminoe oyster, C. ariakensis. Previous studies questioned the reef-building capability of this Crassostrea species, which may affect its habitat function. Through a combination of field and mesocosm studies, I examined …

A Technique To Accelerate Stochastic Markov Chain Monte Carlo Simulations Of Calcium-Induced Calcium Release In Cardiac Myocytes, George Williams, Mohsin Saleet Jafri, Aristide Chikando, Gregory Smith

Arts & Sciences Articles

No abstract provided.

Automated Reduction Of Calcium Release Site Models Via State Aggregation, Yan Hao, Peter Kemper, Gregory D. Smith

Arts & Sciences Articles

No abstract provided.

Summary Tables: Fairfax County And The City Of Alexandria, Virginia Shoreline Inventory Report, Marcia Berman, Harry Berquist, Sharon Killeen, Carl H. Herschner, Karinna Nunez, Karen Reay, Tamia Rudnicky

Reports

The Shoreline Inventory Summary Tables quantify observed conditions based on river systems, such as the combined length of linear features (e.g. shoreline miles surveyed, miles of bulkhead and revetment), the total number of point features (e.g. docks, boathouses, boat ramps) & total acres of polygon features (tidal marshes).

Estimating Detection Probabilities In Beach Seine Surveys For Estuarine Fishes, Branson D. Williams

Dissertations, Theses, and Masters Projects

Detectability, the probability that a species is encountered if it inhabits a site, is often overlooked in fisheries research despite its potential to obscure habitat use inferences. Detectability can be estimated using models that also provide an estimate of occupancy (Ψ), the probability that a species inhabits a site. I used these models to estimate both probabilities, and to examine factors affecting detectability and occupancy for three fishes in Chesapeake Bay tributaries: young-of-the-year striped bass (Morone saxatilis), yearling Atlantic croaker (Micropogonias undulatus), and spottail shiner (Notropis hudsonius). Occupancy models were fitted to data from a seine survey conducted during summer, …

Gis Data: Fairfax County And The City Of Alexandria, Virginia Shoreline Inventory Report, Marcia Berman, Harry Berquist, Sharon Killeen, Carl Hershner, Karinna Nunez, Karen Reay, Tamia Rudnicky

Data

The data inventory developed for the Shoreline Inventory is based on a three‑tiered shoreline assessment approach. In most cases this assessment characterizes conditions that can be observed from a small boat navigating along the shoreline. The three tiered shoreline assessment approach divides the shorezone into three regions: 1) the immediate riparian zone, evaluated for land use; 2) the bank, evaluated for height, stability, cover and natural protection; and 3) the shoreline, describing the presence of shoreline structures for shore protection and recreational purposes. Hand-held GPS units are used to log features observed in the field.

Three GIS coverages are developed …

Modeling Shoreline Change And Resulting Wetland Response Due To Erosion And Sea-Level Rise: A Case Study In Dorchester County, Maryland, Mirtha Karinna Nunez

Dissertations, Theses, and Masters Projects

The present study was focused on developing a shoreline change forecast and wetland response model for Dorchester County, MD, to evaluate the vulnerability of wetlands to shoreline erosion and inundation due to relative sea level rise. The model considers the following forces involved in wetland stability and sustainability: inundation (as a function of topography and sea-level rise), shoreline erosion, vertical accretion and horizontal migration. To predict the long-term risk to nearshore wetlands and the potential habitat zone for wetlands in the next 50 years, shoreline change due to inundation and erosion/accretion was assessed within the frameworks of two-dimensional and three-dimensional …

The Effect Of Salinity On Experimental Hematodinium Sp Infections In The Blue Crab, Callinectes Sapidus, Anna Huntley Coffey

Dissertations, Theses, and Masters Projects

No abstract provided.

Quantifying The Ecosystem Role Of A Suspension And A Facultative Deposit Feeding Bivalve In The New River Estuary, Nc: With Responses To Changes In Nutrient And Sediment Inputs, Heather Marie Wiseman

Dissertations, Theses, and Masters Projects

No abstract provided.

Partial Year Tagging Models: Accounting For Changing Tag Visibility And Delayed Mixing, Lynn Waterhouse

Dissertations, Theses, and Masters Projects

No abstract provided.

Exploring The Potential For Bay Scallop Restoration In The Lynnhaven River Sub-Estuary Of Chesapeake Bay, Ana Liza Hernandez Cordero

Dissertations, Theses, and Masters Projects

No abstract provided.

Alternative Substrates As A Native Oyster (Crassostrea Virginica) Reef Restoration Strategy In Chesapeake Bay, Russell Paul Burke

Dissertations, Theses, and Masters Projects

Oyster shell for native oyster reef restoration is scarce in Chesapeake Bay and other estuaries (Chapter 1). Consequently, alternative substrates merit consideration in oyster restoration. This dissertation examines the suitability of shell alternatives, including granite, concrete, limestone marl, concrete modules and reefballs with reef surveys and experiments in the Rappahannock and Lynnhaven Rivers of Chesapeake Bay. Oyster recruitment, growth, survival, density, biomass, condition, and disease stress, as well as reef accretion and persistence, were measured. In the Lynnhaven River, intertidal riprap had a mean density of 978 oysters m-2 (165 g AFDM m-2) and peak densities > 2000 oysters m-2 (Chapter …

Copepod Carcasses, Mortality And Population Dynamics In The Tributaries Of The Lower Chesapeake Bay, David Thomas. Elliott

Dissertations, Theses, and Masters Projects

Several studies have documented the occurrence of substantial numbers of zooplankton carcasses in marine field samples. However, the potential effect of carcasses on conclusions resting on zooplankton abundance estimates, and the reasons for carcass occurrence have been largely disregarded. Many field studies do not account for the presence of carcasses in their sampling methodology. Zooplankton carcasses in situ are significant for several reasons. as concentrated particles of organic matter in the water column, zooplankton carcasses can be important vehicles for organic matter transport and hotspots of microbial abundance and activity. If dead animals are treated alive, carcasses could bias the …

Bioavailability Of Biosolids- And Consumer Product-Associated Polybrominated Diphenyl Ether (Pbde) Flame Retardants To Terrestrial Invertebrates, Michael O. Gaylor

Dissertations, Theses, and Masters Projects

The primary objectives of this research were therefore to evaluate polybrominated diphenyl ether (PBDE) bioavailability to ecologically distinct soil invertebrates exposed to Penta-BDE-treated consumer polyurethane foam (PUF) products and biosolid products with incurred PBDEs. In laboratory bioassays, earthworms (Eisenia fetida) bioaccumulated SigmaPBDEs (47+99+100+183) up to 11,000 mug/kg lipid after 28 days from a mixture of artificial soil and anaerobically-digested sludge biosolid (ADB). Earthworms also bioaccumulated SigmaPBDEs (47+99+100+153+154+183) up to 13,500 and 838,000 mug/kg lipid after 28 d from a mixture of artificial soil and composted sludge biosolid (CB) and Penta-BDE-spiked artificial soil (SAS), respectively. No previous lab studies on bioaccumulation …

Persistent Organic Pollutants(Pops) As Tracers Of Environmental Change And Antarctic Seabird Ecology, Heidi N. C. Geisz

Dissertations, Theses, and Masters Projects

Antarctic seabirds including Adelie penguins (Pygoscelis adeliae), south polar skuas (Catharacta maccormicki), southern giant petrels (Macronectes gigantus) are high trophic level predators that accumulate persistent organic pollutants (POPs) present in the food webs in which they forage. Little is known about the levels of POPs in some Antarctic organisms (e.g. southern giant petrels), as well as the long-term trends of POPs in the Antarctic ecosystem. Samples from all three seabird species were collected post mortem, including eggs, from the Western Antarctic Peninsula (WAP) and in the Ross Sea throughout the austral summer breeding seasons of 2004--2006. The samples were analyzed …

Effects Of Habitat Quality On Secondary Production In Shallow Estuarine Waters And The Consequences For The Benthic-Pelagic Food Web, David James Gillett

Dissertations, Theses, and Masters Projects

Anthropogenic degradation of coastal and estuarine habitats is an ongoing problem facing scientists, natural resource mangers, and the general public. Decreases in habitat quality produce relatively predictable changes in the structure and composition of macrobenthic communities and it has traditionally been assumed that the ecosystem functions of the community change as well. In Chesapeake Bay, the most pervasive cause for the degradation of benthic habitats is the excessive inputs of nutrients that lead to eutrophication and the accumulation of organic matter in the system. Working within this framework, a study was conducted investigating changes in macrobenthic (i.e., secondary) production along …

Integrating Space-And Time-Scales Of Sediment-Transport For Poverty Bay, New Zealand, Aaron J. Bever

Dissertations, Theses, and Masters Projects

Poverty Bay is a small embayment located in the middle of the Waipaoa River Sedimentary Dispersal System (WSS) on the eastern coast of the north island of New Zealand. Within this dispersal system, a large multidisciplinary study was focused on determining the sediment routing from the source within the headwaters to the locations of sediment accumulation on the continental shelf and slope. Poverty Bay acts as the land to sea transition area in the WSS, and as such significantly modifies the fluvial sedimentary signal before it is exported to the continental shelf. Until this study, little hydrodynamic or sediment-transport work …

Characterization And Deposition Of Aerosol Organic Matter In The Eastern United States, Andrew S. Wozniak

Dissertations, Theses, and Masters Projects

Aerosol organic carbon (OC) was characterized in two eastern United States watersheds to investigate the potential importance of aerosol OC in watershed OC budgets and cycling. Fluxes of 1.7 and 2.1 mg aerosol OC m-2 d-1 were measured for aerosol samples in Harcum, VA and Millbrook, NY, respectively. Scaled to the area of nearby watersheds (York River watershed, VA and Hudson River watershed, NY) these fluxes are similar in magnitude or greater than the magnitude of riverine OC exported by corresponding rivers indicating that aerosols must be taken into account when thinking about biogeochemical exchanges between the atmospheric, terrestrial, and …

Electron Scattering From An Almost Free Neutron In Deuterium, Nathan Kidd Baillie

Dissertations, Theses, and Masters Projects

The Barely off-Shell Nucleon Structure (BoNuS) experiment measured electron scattering from neutrons bound in deuterium nuclei at Jefferson Lab's Hall B with the intent of obtaining the ratio Fn2/Fp2 at high Bjorken x. The Fn2 structure function is difficult to obtain due to nature's lack of a free neutron target. Previous experiments have measured inclusive scattering from atomic nuclei, but extracting Fn2 from these data requires knowledge of inclusive scattering from the proton and corrections for nucleon binding and Fermi motion. In BoNuS we restrict our analysis to neutron scattering events tagged by a backward-going low-energy recoil proton. This selects …

Application Of Information Theory And Statistical Learning To Anomaly Detection, Steven Gianvecchio

Dissertations, Theses, and Masters Projects

In today's highly networked world, computer intrusions and other attacks area constant threat. The detection of such attacks, especially attacks that are new or previously unknown, is important to secure networks and computers. A major focus of current research efforts in this area is on anomaly detection.;In this dissertation, we explore applications of information theory and statistical learning to anomaly detection. Specifically, we look at two difficult detection problems in network and system security, (1) detecting covert channels, and (2) determining if a user is a human or bot. We link both of these problems to entropy, a measure of …

Optical Control Of Ultrafast Spin -Wave Relaxation By Magnetic Anisotropy In A Ferromagnet, Kevin James Smith

Dissertations, Theses, and Masters Projects

This thesis presents an investigation of the damping of spin waves in ferromagnetic Au(3 nm)/Ni(10 nm)/MgO(001) thin films using the time-resolved Magneto-optical Kerr Effect (TR-MOKE) and ferromagnetic resonance (FMR) techniques. In the optical measurements, a 150 fs, 800 nm laser beam pulse is split into pump and probe components. The pump pulse, containing most of the beam energy, thermally excites coherent spin precession. The weaker probe pulse, time-delayed by a variable beam path, captures the magnetization dynamics via the polar MOKE effect, and oscillations are observed as a function of external field amplitude and direction. The extracted precession frequency is …

Quantum Information Dynamics, Jeffrey Yepez

Dissertations, Theses, and Masters Projects

Presented is a study of quantum entanglement from the perspective of the theory of quantum information dynamics. We consider pairwise entanglement and present an analytical development using joint ladder operators, the sum of two single-particle fermionic ladder operators. This approach allows us to write down analytical representations of quantum algorithms and to explore quantum entanglement as it is manifested in a system of qubits.;We present a topological representation of quantum logic that views entangled qubit spacetime histories (or qubit world lines) as a generalized braid, referred to as a super-braid. The crossing of world lines may be either classical or …

Enhancing Web Browsing Security, Chuan Yue

Dissertations, Theses, and Masters Projects

Web browsing has become an integral part of our lives, and we use browsers to perform many important activities almost everyday and everywhere. However, due to the vulnerabilities in Web browsers and Web applications and also due to Web users' lack of security knowledge, browser-based attacks are rampant over the Internet and have caused substantial damage to both Web users and service providers. Enhancing Web browsing security is therefore of great need and importance.;This dissertation concentrates on enhancing the Web browsing security through exploring and experimenting with new approaches and software systems. Specifically, we have systematically studied four challenging Web …

Advancements In Dual-Pump Broadband Cars For Supersonic Combustion Measurements, Sarah Augusta. Tedder

Dissertations, Theses, and Masters Projects

Space- and time-resolved measurements of temperature and species mole fractions of nitrogen, oxygen, and hydrogen were obtained with a dual-pump coherent anti-Stokes Raman spectroscopy (CARS) system in hydrogen-fueled supersonic combustion free jet flows. These measurements were taken to provide time-resolved fluid properties of turbulent supersonic combustion for use in the creation and verification of computational fluid dynamic (CFD) models. CFD models of turbulent supersonic combustion flow currently facilitate the design of air- breathing supersonic combustion ramjet (scramjet) engines. Measurements were made in supersonic axi-symmetric free jets of two scales. First, the measurement system was tested in a laboratory environment using …

Assessing The Functional Status Of Created Wetlands In Eastern Virginia Via A Soil And Vegetative Developmental Trajectory, Sara Elizabeth Kreisel

Dissertations, Theses, and Masters Projects

No abstract provided.

Survival In An Urbanized Landscape: Radio-Tracking Fledgling Eastern Bluebirds (Sialia Sialis) On Golf Courses, Allyson Kathleen Jackson

Dissertations, Theses, and Masters Projects

No abstract provided.

Multifunctional Polymer Synthesis And Incorporation Of Gadolinium Compounds And Modified Tungsten Nanoparticles For Improvement Of Radiation Shielding For Use In Outer Space, Emily Grace Harbert

Dissertations, Theses, and Masters Projects

No abstract provided.