Physical Sciences and Mathematics Commons^™

Three-Dimensional Scene Reconstruction Using Multiple Microsoft Kinects, Matt Miller

Graduate Theses and Dissertations

The Microsoft Kinect represents a leap forward in the form of cheap, consumer friendly, depth sensing cameras. Through the use of the depth information as well as the accompanying RGB camera image, it becomes possible to represent the scene, what the camera sees, as a three-dimensional geometric model. In this thesis, we explore how to obtain useful data from the Kinect, and how to use it for the creation of a three-dimensional geometric model of the scene. We develop and test multiple ways of improving the depth information received from the Kinect, in order to create smoother three-dimensional models. We …

Use Of Ultra High Vacuum Plasma Enhanced Chemical Vapor Deposition For Graphene Fabrication, Shannen Adcock

Graduate Theses and Dissertations

Graphene, what some are terming the "new silicon", has the possibility of revolutionizing technology through nanoscale design processes. Fabrication of graphene for device processing is limited largely by the temperatures used in conventional deposition. High temperatures are detrimental to device design where many different materials may be present. For this reason, graphene synthesis at low temperatures using plasma-enhanced chemical vapor deposition is the subject of much research. In this thesis, a tool for ultra-high vacuum plasma-enhanced chemical vapor deposition (UHV-PECVD) and accompanying subsystems, such as control systems and alarms, are designed and implemented to be used in future graphene growths. …

Mitigating Insider Threat In Relational Database Systems, Qussai Yaseen

Graduate Theses and Dissertations

The dissertation concentrates on addressing the factors and capabilities that enable insiders to violate systems security. It focuses on modeling the accumulative knowledge that insiders get throughout legal accesses, and it concentrates on analyzing the dependencies and constraints among data items and represents them using graph-based methods. The dissertation proposes new types of Knowledge Graphs (KGs) to represent insiders' knowledgebases. Furthermore, it introduces the Neural Dependency and Inference Graph (NDIG) and Constraints and Dependencies Graph (CDG) to demonstrate the dependencies and constraints among data items. The dissertation discusses in detail how insiders use knowledgebases and dependencies and constraints to get …

Recognizing Patterns In Transmitted Signals For Identification Purposes, Baha' A. Alsaify

Graduate Theses and Dissertations

The ability to identify and authenticate entities in cyberspace such as users, computers, cell phones, smart cards, and radio frequency identification (RFID) tags is usually accomplished by having the entity demonstrate knowledge of a secret key. When the entity is portable and physically accessible, like an RFID tag, it can be difficult to secure given the memory, processing, and economic constraints. This work proposes to use unique patterns in the transmitted signals caused by manufacturing differences to identify and authenticate a wireless device such as an RFID tag. Both manufacturer identification and tag identification are performed on a population of …

Role Of Vegetation And Environmental Characteristics On Slope Stability In Northwest Arkansas, Michael Maguigan

Graduate Theses and Dissertations

Slope failure continues to pose risks to society because knowledge of environmental factors and their interactions are unclear and possibly misunderstood. This misunderstanding leads to generalizations about slope failure susceptibility mapping, despite knowing that slope failures are likely the result of an extensively complex set of interactions among a number of environmental, edaphic, and geomorphic characteristics. Therefore a series of experiments were conducted to investigate the effects of slope, soil texture, vegetation cover, bedrock permeability, and compaction,. A wooden flume with a slope face 1 m wide by 1.5 m long with a 10 cm toe was constructed to contain …

Identifying Optimal Cellulosic Biomass Feedstock Supply Areas For Potential Biorefineries In Arkansas, Mark Cooper

Graduate Theses and Dissertations

In February 2010, the U.S. Environmental Protection Agency released the revised Renewable Fuel Standard (RFS2), mandating at least 36 billion gallons of renewable fuels to be produced annually in America, and blended into all on/off road, locomotive, and marine gasoline and diesel by the year 2022. America's existing biorefineries fall significantly short of being able to meet this mandate, resulting in the need for rapid expansion in the near future if this goal is to be met. The state of Arkansas has abundant resources to offer the renewable energy industry, if properly utilized. The goal of this thesis is to …

Pointwise Schauder Estimates Of Parabolic Equations In Carnot Groups, Heather Arielle Griffin

Graduate Theses and Dissertations

Schauder estimates were a historical stepping stone for establishing uniqueness and smoothness of solutions for certain classes of partial differential equations. Since that time, they have remained an essential tool in the field. Roughly speaking, the estimates state that the Holder continuity of the coefficient functions and inhomogeneous term implies the Holder continuity of the solution and its derivatives. This document establishes pointwise Schauder estimates for second order parabolic equations where the traditional role of derivatives are played by vector fields generated by the first layer of the Lie algebra stratification for a Carnot group. The Schauder estimates are shown …

Stratigraphy And Provenance Of Shallow Sandstones Endountered In Wells In Townships 9 And 10 North, Ranges 6 And 7 West, White County, Arkansas, Lacie Knight

Graduate Theses and Dissertations

Paleozoic formations in western Arkansas have been well-studied; however, they are not well-understood in the eastern part of the state. The study area encompasses Townships 9. N. and 10. N., Ranges 6. W. and 7. W. in north-central White County, Arkansas. This area is at the intersection of four physiographic provinces as defined by the Arkansas Geologic Survey- the Ozark Plateaus, the Arkansas River Valley, the Ouachita Mountains, and the Mississippi Alluvial Plain. Interpretations of the surface unit in the area disagree. The Arkansas Geologic Map shows that the Morrowan Hale Formation crops out in the area; however, various petroleum …

Extending The Hybridthread Smp Model For Distributed Memory Systems, Eugene Anthony Cartwright Iii

Graduate Theses and Dissertations

Memory Hierarchy is of growing importance in system design today. As Moore's Law allows system designers to include more processors within their designs, data locality becomes a priority. Traditional multiprocessor systems on chip (MPSoC) experience difficulty scaling as the quantity of processors increases. This challenge is common behavior of memory accesses in a shared memory environment and causes a decrease in memory bandwidth as processor numbers increase. In order to provide the necessary levels of scalability, the computer architecture community has sought to decentralize memory accesses by distributing memory throughout the system. Distributed memory offers greater bandwidth due to decoupled …

Investigation Of Negative Differential Resistance Phenomena In Quantum Well Heterostructures, Nazariy Andrushchak

Graduate Theses and Dissertations

Increasing interest in entirely new possibilities for quantum mechanical description of carriers transport is becoming more evident with the developing advancements in epitaxial growth technique. Consequently, molecular beam epitaxy (MBE) technique is considered to be the most precise technique that allows the growth of ultra-thin layers of different compositions.

Those structures can be designed to investigate the wave-nature of carriers, which broadens the possibilities in device design and fabrication for a specific area. In this thesis the fundamental study of the real space charge transfer (RST) mechanism that took place in quantum well heterostructures and led to the negative differential …

Data Integration And Reservoir Characterization Of The Pennsylvanian Bartlesville Sandstone, Caroline Vance O'Keefe

Graduate Theses and Dissertations

The Glenn Pool Oil Field of Northeastern Oklahoma was established as the first major oil discovery of the fledgling state of Oklahoma. Fully developed by 1912, the field is now nearing depletion even under secondary and tertiary recovery efforts after production for approximately 100 years. Large amounts of residual oil estimated to still be in place have motivated exploration into other recovery methods, including polymer flooding and horizontal drilling. Success of these programs is dependent upon accurate characterization of the reservoir. Because most of the drilling occurred many decades ago, much of the data associated with this field predates electric …

Experimental Simulations Of Dark Slope Streaks On Mars, Kelly Howe

Graduate Theses and Dissertations

Martian slope streaks were first observed in Viking images but their formation still remains ambiguous. Martian slope streaks are currently occurring geological phenomenon on Mars, which requires any formation theory to be in agreement with Mar's current temperature and pressure conditions. Planar morphology of martian slope streaks suggest a potential fluvial formation, but current conditions on Mars are not conducive to water remaining liquid long enough to erode the surface. Debris flows, fluid stains and dry dust avalanches have all been previously cited as a potential formation mechanism for martian slope streaks. Recent experimental simulations indicate that a fluvial source …

Mott Transition And Electronic Structure In Complex Oxide Heterostructures, Jian Liu

Graduate Theses and Dissertations

Strongly correlated electron systems, particularly transition metal oxides, have been a focus of condensed matter physics for more than two decades since the discovery of high-temperature superconducting cuprates. Diverse competing phases emerge, spanning from exotic magnetism to unconventional superconductivity, in proximity to the localized-itinerant transition of Mott insulators. While studies were concentrated on bulk crystals, the recent rapid advance in synthesis has enabled fabrication of high-quality oxide heterostructures, offering a new route to create novel artificial quantum materials.

This dissertation details the investigation on ultrathin films and heterostructures of 3d⁷(t_2g⁶e_g¹) systems with …

Territories,Territoriality, And Conservation Of The Louisiana Waterthrush And Its Habitat, The Watershed Of The Upper Buffalo National River, Leesia Cheryl Marshall

Graduate Theses and Dissertations

The Louisiana Waterthrush, Parkesia motacilla, is a migratory wood-warbler and breeding season resident of the eastern United States. Males defend breeding territories that extend linearly along clear, fast-flowing, gravel-bottomed, forest streams. Defense includes two song types, primary and extended song. As riverine specialists, birds rely upon aquatic invertebrates as prey and riparian habitat features for nesting. They use a unique foraging maneuver, leaf-pulling, that involves picking up or pulling a leaf from water, and turning it over to search for prey. Their relationship with riparian habitat introduces potential for Louisiana Waterthrushes to serve as indicators of stream health. The …

Wayne E. Sabbe Arkansas Soil Fertility Studies 2011, Nathan A. Slaton

Arkansas Agricultural Experiment Station Research Series

The studies described within will allow producers to compare their practices with the university’s research efforts. Additionally, soil-test data and fertilizer sales are presented to allow comparisons among years, crops, and other areas within Arkansas.

Object Recognition Based On Shape And Function: Inspired By Children's Word Acquisition, Akihiro Eguchi

Inquiry: The University of Arkansas Undergraduate Research Journal

This paper explores a new approach to computational object recognition by borrowing an idea from child language acquisition studies in developmental psychology. Whereas previous image recognition research used shape to recognize and label a target object, the model proposed in this study added the function of the object resulting in a more accurate recognition. This study makes use of new gaming technology, Microsoft’s Kinect, in implementing the proposed new object recognition model. A demonstration of the model developed in this project properly infers different names for similarly shaped objects and the same name for differently shaped objects.

In Memoria: Art Fry, 1921-2011, Collis Geren

Journal of the Arkansas Academy of Science

No abstract provided.

Investigating 3 Axis Cnc Processes For Creating 3d Objects, Michael Jake Newsum

Inquiry: The University of Arkansas Undergraduate Research Journal

Using 3 axis CNC (computer numerical code) routing processes of the Visualization Lab, the CNC was tested for 3D object milling. The CNC process was designed for manufacturing 2D cut out objects with or without a 3D surface. The processes of modeling the object, using CAM (Computer Aided Manufacturing) programs, producing the Toolpath, post processing, editing G Code, positioning the stock material, and setting the machine origin were tested for an understanding of what changes had to be made to the process to accurately mill and cut out 3D objects. Solutions were discovered through digital and physical setups that are …

Sestonic Chlorophyll-A And Nutrient Relationships Across The Red River Basin, Usa, Brian E. Haggard, J. Thad Scott, Scott D. Longing, John T. Metrailer

Technical Reports

The Red River is a trans‐boundary, multi‐jurisdictional basin, where water‐quality standards often change at the state lines. The state agencies with USEPA Region VI focused resources to organize water‐quality data from within this basin and have it statistically analyzed to evaluate the relationships between nutrients and sestonic chlorophyll‐a (chl‐a). There were 152 sites within the Red River Basin that had nutrient and sestonic chl‐a data, and these sites were narrowed down to 132 when a minimum number of observations was required. Sestonic chl‐a levels increased with increasing nutrient concentrations; these significant regressions were used to predict nutrient concentrations at 10 …

Nutrient Criteria Development Mini-Workshops For Usepa Region Vi States, Brian E. Haggard, J. Thad Scott

Technical Reports

The U.S. Environmental Protection Agency (USEPA) has been encouraging states to accerlate their efforts in developing numeric nutrient criteria to promulgate within respective water quality standards and regulations. Based on USEPA recommendations, many states are pursuing nutrient criteria development by assessing frequency distributions and stressor‐response relationships in historical databases, various special studies and the literature. The mini‐workshops described here were targeted toward state agency personnel and stakeholder groups with an interest in understanding statistical techniques that could be used to aide, guide and support numeric nutrient criteria. An initial workshop was conducted at the USEPA Regional Technical Assistance Group meeting …

Water Quality Trends Across Select 319 Monitoring Sites In Northwest Arkansas, Bryan W. Bailey, Brian E. Haggard, Leslie B. Massey

Technical Reports

Northwest Arkansas contains two 319 priority watersheds that the Arkansas Natural Resources Commission has identified as being impacted by point source and nonpoint source pollution (i.e., phosphorus, nitrogen, and sediment). This project specifically focused on determining water quality trends at select sites within the Illinois River (HUC# 11110103) and Beaver Reservoir (HUC# 11010001) priority watersheds, including Ballard Creek, Osage Creek, Illinois River, White River, West Fork White River and the Kings River where sufficient constituent data were available. Water quality trends were analyzed using flow‐adjusted constituent concentrations of phosphorus, nitrogen, sediment, sulfate and chloride, and parametric and non‐parametric statistical techniques …

Wi-Fi Sensing Algorithms Utilizing Zigbee Rf Receiver For Use In Emergency Communications Mesh, Alexander H. Nelson

Inquiry: The University of Arkansas Undergraduate Research Journal

This thesis examines a low-power Wi-Fi sensing wake-up controller for an emergency communications mesh network; the goal of the research study is to progressively develop a prototype system that could be used in a live environment. Wireless network protocols are reviewed, in addition to a limited view of cluster analysis, in order to introduce relevant receiver concepts crucial to understanding this study. Algorithms for system implementation are developed, and pseudocode, designed to be configurable and platform-independent, is given for each. The system’s design goals are identified, followed by a discussion on approaches and optimizations in order to maximize the system’s …

Impervious Surface Area Change In Arkansas From 2001 To 2006, D. E. Long Ii, R. C. Weih Jr.

Journal of the Arkansas Academy of Science

Impervious Surface Area (ISA) is a measurement used to determine stream quality as well as urban sprawl. ISA was calculated as part of the National Land Cover Dataset (NLCD) using Landsat imagery by the Multi-Resolution Land Characteristics Consortium (MRLC) in both 2001 and 2006. ISA for each of the 75 counties in Arkansas was taken from the NLCD for both 2001 and 2006. Using the ISA data, percent imperviousness was determined for each county in each time period as well as the difference between the two periods. These data were also compared to census projections for the two time periods …

Synthesis And Optical Properties Of Sprayed Zno And Zno:Ga Thin Films, N. F. Habubi, S. S. Chiad, S. Jabbar, W. Jabbar

Journal of the Arkansas Academy of Science

Characteristics and optical constants of pure and Ga-doped ZnO thin films have been studied. Pure and Ga-doped zinc oxide thin films were deposited onto glass substrates using the spray pyrolysis technique. Optical absorption studies in the wavelength range of 300–900 nm showed a peak near 450 nm for different doped films (in addition to the peak for un-doped ZnO). Increasing the doping concentration of Ga to 7% induced an increase in the optical constants of films. This increase is attributed to the formation of chargetransfer complexes. ZnO thin films doped with Ga have improved the optical transmittance in the visible …

Fabrication And Characterization Of Aluminum-Doped Zno/Pani Hybrid Solar Cells, S. Abdulalmohsin, S. M. Al-Mutoki, Z. Li

Journal of the Arkansas Academy of Science

We report a facile method to fabricate an AZO/PANI heterostructure by a sandwiching technique. Aluminum-doped ZnO (AZO) films were deposited onto indium tin oxide (ITO) glass using the sputtering technique while PANI films were deposited onto ITO glass using electropolymerization. The optoelectric properties of the inorganic/organic device were characterized

Interacting Dark Energy Models And The Cosmic Coincidence Problem, H. Shojaei, C. Smith, D. Waters

Journal of the Arkansas Academy of Science

Interacting dark energy models have been employed to study the behavior of dark energy and matter in the presence of an interaction between the two. One of the successful aspects of these models is how they explain the cosmic coincidence problem. In this work we consider a specific interaction to study the behavior of dark energy and matter through the history of evolution.

Current Range In Lightning Return Strokes, M. Hemmati, W. P. Childs, D. C. Waters, J. R. Christensen, B. C. Richard

Journal of the Arkansas Academy of Science

In our investigation of breakdown waves, we use a one-dimensional, steady-state, constant velocity fluid model. This investigation involves breakdown waves for which the electric field force on electrons is in the opposite direction of wave propagation. The waves are considered to be shock fronted and the electron gas partial pressure is large enough to sustain the wave propagation. Our basic set of electron fluid-dynamical equations is composed of the equations for conservation of mass, momentum and energy, coupled with Poisson’s equation. This investigation involves breakdown waves for which a large current exists behind the shock front. The current behind the …

Establishing Baseline Nutrient And Sediment Input In The Lower Cache River Watershed, Ar, A. M. Gilmer, C. A. Rosado-Berrios, J. L. Bouldin

Journal of the Arkansas Academy of Science

Contaminants in waterways continue to be a problem especially in watersheds dominated by land use changes such as agriculture. Clearing the land for agricultural use is needed to support the population; however, agricultural contaminants are cited as contributing the greatest input of suspended solids and nutrients to waterways. Quantifying various contaminants in surface water is useful in determining their origin, thus aiding in their mitigation. This study, focused on the Cache River Watershed, reports pH, dissolved oxygen (DO), conductivity, turbidity, total suspended solids (TSS), NO3 - , NO2 - , and PO4 3- in the lower sub watersheds. It was …

Electrochemical Polymerization Of Ppy-Mwcnt Composite As A Counter Electrode For Dye-Sensitized Solar Cells, S. Abdulalmohsin, S. M. Al-Mutoki, Z. Li

Journal of the Arkansas Academy of Science

Polypyrrole (PPy) - multi wall carbon nanotube (MWCNT) nanocomposites were synthesized by using in situ electrochemical polymerization with different COOH-functionalized MWCNTs. The PPY-MWCNT composites were used as counter electrode in the fabrication of dye sensitized solar cells (DSCs). Compared to the DSC device with PPy counter electrode, the devices with PPY/MWCNT composite electrode offer much higher total photovoltaic conversion efficiency due to the reduced series resistance. These PPY/MWCNT nanocomposite materials proved to be a good alternate to the expensive Pt as counter electrode in DSC.

Comparing Methods For Interpolation To Improve Raster Digital Elevation Models, J. C. Guarneri, R. C. Weih Jr.

Journal of the Arkansas Academy of Science

Digital elevation models (DEMs) are available as raster files at 100m, 30m, and 10m resolutions for the contiguous United States and are used in a variety of geographic analyses. Some projects may require a finer resolution. GIS software offers many options for interpolating data to higher resolutions. We compared ten interpolation methods using 10m sample data from the Ouachita Mountains in central Arkansas. We interpolated the 10m DEM to 5m, 2.5m, and 1m resolutions and compared the absolute mean difference (AMD) for each using surveyed control points. Overall, there was little difference in the accuracy between interpolation methods at the …