Digital Commons Network^™

Challenges For Λcdm And Mond, Stacy S. Mcgaugh

Faculty Scholarship

The Universe on large scales is well described by the ΛCDM cosmological model. There however remain some heavy clouds on our global understanding, especially on galaxy scales, which we review here. While some of these clouds might perhaps disappear through small compensatory adjustments of the model, such as changing the mass of the dark matter particles or accounting better for baryonic physics, others should rather be taken as strong indications that the physics of the dark sector is, at the very least, much richer and complex than currently assumed, and that our understanding of gravity and dynamics might also be …

Teachers’ And Administrators’ Use Of Evidence Of Student Learning To Take Action: Conclusions Drawn From A Special Issue On Formative Assessment, Heidi Andrade, M. Christina Schneider

Educational Theory and Practice Faculty Scholarship

A teacher who collects and analyzes diverse types of evidence of a student’s learning and uses that information to either adjust instruction or provide feedback to the student is using formative classroom assessment (Brookhart, Moss, & Long, 2008). A central feature of formative assessment is a clear link between the results of an assessment and subsequent actions that lead to gains in student learning (Nichols, Meyers, & Burling, 2009; Wiliam, 2010). The impact of formative assessment is greatly diminished if teachers are not able to use evidence of student learning to determine next instructional steps and help students move their …

Toward Fostering Environmental Political Participation: Framing An Agenda For Environmental Education Research, Brett L. M. Levy, Michaela T. Zint

Educational Theory and Practice Faculty Scholarship

Scholars of environmental education (EE) and education for sustainable development (ESD) have been among the environmental leaders calling for individuals to become increasingly engaged in political action aimed at addressing environmental and sustainability issues. Few, however, have studied how educational experiences might foster greater environmental political engagement. Fortunately, there is a rich body of research in political science, psychology, and education that provides insights that EE and ESD scholars and educators can build on. Studies in these domains suggest, for example, that political efficacy (the belief that individuals’ actions can influence political processes) and political interest (individuals’ willingness to pay …

Infusing Problem-Based Learning (Pbl) Into Science Methods Courses Across Virginia, K. R. Thomas, P. L. Horne, S. M. Donnelly, C. T. Berube

Journal of Mathematics and Science: Collaborative Explorations

This article outlines the results of a collaborative study of the effects of infusing problem-based learning (PBL) into K-12 science methods courses across four universities in Virginia. Changes in pre-service teachers' attitudes surrounding science teaching were measured before and after completing a science methods course in which they experienced PBL first-hand as participants, and then practiced designing their own PBL units for use in their future classrooms. The results indicate that exposure to PBL enhances pre-service teachers' knowledge of inquiry methods and self-efficacy in teaching science.

Grappling With Issues Of Learning Science From Everyday Experiences: An Illustrative Case Study, A.-L. Tan, M. Kim, F. Talaue

Journal of Mathematics and Science: Collaborative Explorations

There are different perceptions among researchers with regard to the infusion of everyday experience in the teaching of science: 1) it hinders the learning of science concepts; or, 2) it increases the participation and motivation of students in science learning. This article attempts to contemplate those different perspectives of everyday knowledge in science classrooms by using everyday contexts to teach grade 3 science in Singapore. In this study, two groups of grade 3 students were presented with a scenario that required them to apply the concept of properties of materials to design a shoe. Subsequently, the transcripts of classroom discussions …

A Lesson Plan With An Arc Midpoint, G. V. Akulov, O. G. Akulov

Journal of Mathematics and Science: Collaborative Explorations

The article introduces an explicit way of locating the arc midpoint in the Cartesian plane, which is consistent for both x- and y-coordinates and is technically accessible for students starting as young as fifteen. The authors give the proof of the statement using two trigonometry identities, and discuss some materials for innovative lessons on the arc midpoint computation that could enrich and enhance curriculum.

Building A Case For Mathematics Specialist Programs, D. Blount, J. Singleton

Journal of Mathematics and Science: Collaborative Explorations

No abstract provided.

Unlocking Undergraduate Problem Solving, D. Cline, K. Peterson

Journal of Mathematics and Science: Collaborative Explorations

It is difficult to find good problems for undergraduates. In this article, we explore an interesting problem that can be used in virtually any mathematics course. We then offer natural generalizations, state and prove some related results, and ultimately end with several open problems suitable for undergraduate research. Finally, we attempt to shed some light on what makes a problem interesting.

Reform Teaching In Mathematics And Science Courses — A Follow-Up Evaluation, G. M. Bass Jr.

Journal of Mathematics and Science: Collaborative Explorations

No abstract provided.

Journal Of Mathematics And Science: Collaborative Explorations

Journal of Mathematics and Science: Collaborative Explorations

No abstract provided.

Factors Influencing The Establishment And Survival Of Native Hardwood Tree Seedlings Of The Kentucky Inner Bluegrass Blue Ash-Oak Savanna-Woodland, James D. Shaffer

Theses and Dissertations--Biology

Historically, the Kentucky Inner Bluegrass blue ash-oak savanna-woodland was the primary ecosystem of the Inner Bluegrass Region (IBR) of Kentucky. After European settlement, the majority (>99%) of Bluegrass savanna was converted to agricultural and urban land uses. Currently remnant savanna tree species are failing to recruit. Therefore, a long-term restoration ecology project researching competition and disturbance on seedling establishment, survival, and growth has been established at Griffith Woods (the largest remaining savanna in Kentucky) in Harrison Co., KY. Fourteen native hardwood tree species (a total of 6,168 seedlings) have been experimentally planted. Light, soil, surrounding vegetation, and herbivory, factors …

On Stretch Factors Of Greedy Routing Algorithms, Omkar U. Kulkarni

Dissertations

Routing aims to find a path to deliver the information from a source to the destination in the network. Routing is one of the most important algorithmic problems in networking. Our research focuses primarily on greedy routing algorithms. The greedy routing algorithms always compute a routing path by forwarding a message to a neighbor closer to the destination than itself. The closeness to the destination can be measured differently via different notions of distances. Greedy routing algorithms keep forwarding the message to a neighbor closer to the destination than itself until the distance to the destination reduces to zero. When …

Detailed Methodology For Determining Torque Limits To Maximize Preload For High-Strength Threaded Fasteners, D. Andy Hissam

Dissertations

High-strength threaded fasteners are an amazing product of engineering, and one of the most common methods of making structural attachments. They are frequently used in structural joints because of two important features: such fasteners allow disassembly and reassembly of the joint, and they can generate high clamping loads called preload. To achieve the full benefit of threaded fasteners, the initial preload must be maximized. The benefits of high preload are well documented and include improved fatigue resistance, increased joint stiffness, and better resistance to vibration loosening. For joints in shear, preload resists relative motion, or slip, of the clamped members. …

Bound Orbits And Virialized Systems In A Dark Energy Universe, Kristen Lackeos

Dissertations

It is shown that at sufficiently large radii dark energy modifies the behavior of (a) bound orbits around a galaxy, and (b) virialized gas in a cluster of galaxies. In (a), there exists a maximum circular orbit beyond which periodic motion is no longer possible, and the evolution of orbits near critical binding is analytically calculable using an adiabatic invariant integral. The finding may have application to wide galaxy pairs. In (b), dark energy necessitates the use of the generalized Virial Theorem to describe gas at the outskirts of a cluster. As a result, gas at a radius of 4 …

The Effects Of Mean Sea Level And Tidal Amplitude On Ground Water Discharge And Pore-Water Salinity Distribution Along A Forest/Marsh Boundary, North Inlet, Sc, John Bradley Peurifoy

Theses and Dissertations

Advective groundwater flow in salt marshes is an important mechanism through which nutrients are exported to adjacent coastal waters. Groundwater flow also influences the distribution of pore-water salinity in the subsurface marsh, which affects botanical zonation, nutrient transport, and primary productivity. Recent idealized marsh island simulations have suggested that increases in tidal amplitude result in increased groundwater discharge, and that the elevation of MWL relative to the marsh platform is inversely related to groundwater discharge. These simulations were only representative of marsh islands (as opposed to forest-marsh boundaries) and relied on simulated tides and MWL position. The results were not …

Active Optimal Control Strategies For Increasing The Efficiency Of Photovoltaic Cells, Sharif Aljoaba

Theses and Dissertations--Electrical and Computer Engineering

Energy consumption has increased drastically during the last century. Currently, the worldwide energy consumption is about 17.4 TW and is predicted to reach 25 TW by 2035. Solar energy has emerged as one of the potential renewable energy sources. Since its first physical recognition in 1887 by Adams and Day till nowadays, research in solar energy is continuously developing. This has lead to many achievements and milestones that introduced it as one of the most reliable and sustainable energy sources. Recently, the International Energy Agency declared that solar energy is predicted to be one of the major electricity production energy …

Fpga-Based Implementation Of Dual-Frequency Pattern Scheme For 3-D Shape Measurement, Brent Bondehagen

Theses and Dissertations--Electrical and Computer Engineering

Structured Light Illumination (SLI) is the process where spatially varied patterns are projected onto a 3-D surface and based on the distortion by the surface topology, phase information can be calculated and a 3D model constructed. Phase Measuring Profilometry (PMP) is a particular type of SLI that requires three or more patterns temporarily multiplexed. High speed PMP attempts to scan moving objects whose motion is small so as to have little impact on the 3-D model. Given that practically all machine vision cameras and high speed cameras employ a Field Programmable Gate Array (FPGA) interface directly to the image sensors, …

Target Tracking With Binary Sensor Networks, Mengmei Liu

Theses and Dissertations--Electrical and Computer Engineering

Binary Sensor Networks are widely used in target tracking and target parameter estimation. It is more computationally and financially efficient than surveillance camera systems. According to the sensing area, binary sensors are divided into disk shaped sensors and line segmented sensors. Different mathematical methods of target trajectory estimation and characterization are applied. In this thesis, we present a mathematical model of target tracking including parameter estimation (size, intrusion velocity, trajectory, etc.) with line segmented sensor networks. Software simulation and hardware experiments are built based on the model. And we further analyze how the quantization noise affects the results.

An Attitude Determination System With Mems Gyroscope Drift Compensation For Small Satellites, Maxwell Bezold

Theses and Dissertations--Electrical and Computer Engineering

This thesis presents the design of an attitude determination system for small satellites that automatically corrects for attitude drift. Existing attitude determination systems suffer from attitude drift due to the integration of noisy rate gyro sensors used to measure the change in attitude. This attitude drift leads to a gradual loss in attitude knowledge, as error between the estimated attitude and the actual attitude increases.

In this thesis a Kalman filter is used to complete sensor fusion which combines sensor observations with a projected attitude based on the dynamics of the satellite. The system proposed in this thesis also utilizes …

Visual Attitude Propagation For Small Satellites, Samir Ahmed Rawashdeh

Theses and Dissertations--Electrical and Computer Engineering

As electronics become smaller and more capable, it has become possible to conduct meaningful and sophisticated satellite missions in a small form factor. However, the capability of small satellites and the range of possible applications are limited by the capabilities of several technologies, including attitude determination and control systems. This dissertation evaluates the use of image-based visual attitude propagation as a compliment or alternative to other attitude determination technologies that are suitable for miniature satellites. The concept lies in using miniature cameras to track image features across frames and extracting the underlying rotation.

The problem of visual attitude propagation as …

Perceptual Ruler For Quantifying Speech Intelligibility In Cocktail Party Scenarios, Kirstin M. Brangers

Theses and Dissertations--Electrical and Computer Engineering

Systems designed to enhance intelligibility of speech in noise are difficult to evaluate quantitatively because intelligibility is subjective and often requires feedback from large populations for consistent evaluations. Attempts to quantify the evaluation have included related measures such as the Speech Intelligibility Index. These require separating speech and noise signals, which precludes its use on experimental recordings. This thesis develops a procedure using an Intelligibility Ruler (IR) for efficiently quantifying intelligibility. A calibrated Mean Opinion Score (MOS) method is also implemented in order to compare repeatability over a population of 24 subjective listeners. Results showed that subjects using the IR …

Parametric Average-Value Model Of Rectifiers In Brushless Excitation Systems, Thaer Qunais

Theses and Dissertations--Electrical and Computer Engineering

An average-value model of a rotating rectifier circuit in a brushless excitation system is set forth, where a detailed simulation is required to extract the essential averaged-model parameters using numerical averaging. In the proposed approach, a synchronous machine model with saturation and cross saturation and an arbitrary rotor network representation that uses a voltage-behind-reactance representation for the field winding of the main machine is proposed. This allows the field winding to be represented as branches in a circuit solver, permitting straightforward simulation with connected circuitry. Also a brushless exciter model is introduced to be compatible with the averaged-model, where the …

The Point Of A Points System: Attracting Highly Skilled Immigrants The United States Needs And Ensuring Their Success, Carla Tabag

Vanderbilt Journal of Transnational Law

In a globalizing world, labor is an increasingly mobile and competitive resource. Responding to this changing labor market, countries like Canada, the United Kingdom, and Australia have adopted points systems with the goal of attracting talented, highly skilled immigrants. In the United States, however, much of the national focus on immigration remains on deterring illegal immigration rather than attracting immigrants that the United States needs to remain competitive in a globalized world. But attracting skilled immigrants is only one ingredient to a successful points system; a country must also ensure those immigrants are successful and use their talents to the …

Removal Of Synthetic Organic Compounds And Nom By Single-Walled Carbon Nanotubes-Ultrafiltration And Forward Osmosis Membrane System, Jiyong Heo

Theses and Dissertations

This overall theme of this dissertation is to investigate the potential engineered application of low pressure membranes incorporated with single-walled carbon nanotubes (SWNTs) and forward osmosis (FO) membrane systems for the removal of synthetic organic compounds (SOCs) and natural organic matter (NOM) from drinking water sources. The focus is on the use of SWNTs-ultrafiltration (UF) and FO membrane systems to facilitate the removal of these compounds and potential applications of these membrane system designs for reducing the energy demands and membrane fouling in environmental water filtration process and seawater desalination. The SWNTs-UF results indicate that SOCs transport is influenced by …

Application Of Agent-Based Approaches To Enhance Container Terminal Operations, Omor Sharif Abul Bashar Mohammad

Theses and Dissertations

Queuing at marine terminal gates has long been identified as a source of emissions and high drayage costs due to the large number of trucks idling. The first study in this dissertation addresses queuing of trucks at marine terminal gates and presents a novel agent-based framework where the drayage companies can minimize congestion by using the provided real-time gate queuing information. The problem was tackled based on the approach of El Farol Bar problem from game theory. Our proposed model can be used as a means of managing demand for the marine terminals, assuming that drayage firms will adjust their …

A Content Analysis To Investigate The Evidence Of 21st Century Knowledge And Skills Within Elementary Teacher Education Programs In The United States, Mary Margaret Ruettgers

Dissertations

Are graduates of teacher preparation programs adequately prepared with the skills and knowledge to teach in the 21st century classroom? This study consisted of a quantitative content analysis to investigate the presence of 21st century knowledge and skills within a stratified random sample of teacher preparation programs in the United States as measured by the 21st Century Learning Framework. Based on the current literature, the researcher identified 21st century competencies: global awareness; digital competencies; critical thinking; collaboration; cross-cultural; communication; and problem solving. For null hypothesis numbers two through eight, the researcher determined how closely the institution’s mission statements, course descriptions, …

The Mc-Dagum Distribution And Its Statistical Properties With Applications, Broderick O. Oluyede, Sasith Rajasooriya

Mathematical Sciences: Faculty Publications

In this paper, a new class of distributions called Mc-Dagum distribution is proposed. This class of distributions contains several distributions such as beta-Dagum, beta-Burr III, beta-Fisk, Dagum, Burr III and Fisk distributions as special cases. The hazard function, reverse hazard function, moments, mean residual life function, Renyi entropy and Fisher information are obtained. Lorenz, Bonferroni and Zenga curves are derived. Maximum likelihood estimates of the model parameters and numerical examples are given to illustrate the usefulness of the proposed class of distributions.

Speech Sensorimotor Learning Through A Virtual Vocal Tract, Jeffrey J. Berry, Cassandra North, Benjamin Meyers, Michael T. Johnson

Speech Pathology and Audiology Faculty Research and Publications

Studies of speech sensorimotor learning often manipulate auditory feedback by modifying isolated acoustic parameters such as formant frequency or fundamental frequency using near real-time resynthesis of a participant's speech. An alternative approach is to engage a participant in a total remapping of the sensorimotor working space using a virtual vocal tract. To support this approach for studying speech sensorimotor learning we have developed a system to control an articulatory synthesizer using electromagnetic articulography data. Articulator movement data from the NDI Wave System are streamed to a Maeda articulatory synthesizer. The resulting synthesized speech provides auditory feedback to the participant. This …

Capturing And Modeling A Three-Dimensional Stationary Noise Source Directivity Pattern With A Dynamic Array In The Near Field, Randy Mieskoski

Browse all Theses and Dissertations

The author has studied several legacy landmark methodologies to develop an original measurement technique. Spherical harmonics modeling practices were leveraged to accurately represent a source directivity pattern. In this thesis a lightweight microphone measurement array that was manually maneuvered around a static noise source was employed. The measurement technique consisted of inserting a head-tracker sensor onto the microphone array to allow the location of the captured acoustic Sound Pressure Level (SPL) to be investigated. By leveraging the historical methodologies the acoustic SPL and location data collected with this technique were processes to represent a directivity pattern of the compressor source …

Post-Emplacement Leaching Behaviors Of Nano Zero Valent Iron Modified With Carboxymethylcellulose Under Simulated Aquifer Conditions, Leslie Lavinia Williams

Browse all Theses and Dissertations

Nanoscale particles of zero valent iron stabilized with carboxymethylcellulose (CMC-nZVI) have been shown to degrade chlorinated hydrocarbons efficiently in bench-scale investigations. The remediation of contaminated sites by subsurface injection of stabilized nZVI in a slurry form has been investigated at pilot scale and field scale with conflicting results concerning transport of stabilized nZVI and its long-term stability for in situ degradation of chlorinated hydrocarbons. Changes in the hydraulic conductivity in porous media have also been reported following injection of stabilized nZVI slurry in both large tank experiments and in field studies. This study investigated the leaching behavior of CMC-nZVI post-emplacement …