Digital Commons Network^™

Stationary Nonimaging Concentrators – A Comprehensive Study And Design Improvements, Srikanth Madala

UNLV Theses, Dissertations, Professional Papers, and Capstones

Most places on our planet receive an annual average radiation between 800-1000 W/m2. In the man-made world, this radiation is largely incident on stationary structures such as buildings, roads, monuments, bridges etc. Moreover, in the natural world also, there are large tracts of barren land which can be put to good use given their solar energy potential. The vision of the current research is to concentrate all this available solar energy to a more readily usable form. Therefore, stationary nonimaging solar concentrator technologies are sought after. This dissertation work is an exhaustive research on the nonimaging concentrating mechanisms with stationary …

A Business Intelligence Framework For Network-Level Traffic Safety Analyses, Naveen Kumar Veeramisti

UNLV Theses, Dissertations, Professional Papers, and Capstones

Currently, there are both methodological and practical barriers that together preclude a substantial use of theoretically sound approaches, such as the ones recommended by the Highway Safety Manual (HSM), for traffic safety management. Although the state-of-the-art provides theoretically sound approaches such as the Empirical Bayes method, there are still various important capabilities missing. Methodological barriers include among others (i) lack of a theoretically sound approach for corridor-level network screening, (ii) lack of a comprehensive approach for estimation of Safety Performance Functions based on a simultaneous consideration of both crash patterns and associated explanatory variables, and (iii) lack of theoretically sound …

Galaxy And Mass Assembly (Gama) : Detection Of Low-Surface-Brightness Galaxies From Sdss Data., Richard P. Williams, I. K. Baldry, L. S. Kelvin, P. A. James, S. P. Driver, M. Prescott, S. Brough, M. J. I. Brown, L. J. M. Davies, Benne W. Holwerda, J. Liske, P. Norberg, A. J. Moffett, A. H. Wright

Faculty and Staff Scholarship

We report on a search for new low-surface-brightness galaxies (LSBGs) using Sloan Digital Sky Survey (SDSS) data within the Galaxy And Mass Assembly (GAMA) equatorial fields. The search method consisted of masking objects detected with SDSS photo, combining gri images weighted to maximize the expected signal-to-noise ratio, and smoothing the images. The processed images were then run through a detection algorithm that finds all pixels above a set threshold and groups them based on their proximity to one another. The list of detections was cleaned of contaminants such as diffraction spikes and the faint wings of masked objects. From these, …

Assessment Of Asymmetric Flight On Solar Uas, Eric Belfield

Master's Theses

An investigation was conducted into the feasibility of using an unconventional flight technique, asymmetric flight, to improve overall efficiency of solar aircraft. In this study, asymmetric flight is defined as steady level flight in a non-wings-level state in- tended to improve solar incidence angle. By manipulating aircraft orientation through roll angle, solar energy collection is improved but aerodynamic efficiency is worsened due to the introduction of additional trim drag. A point performance model was devel- oped to investigate the trade-off between improvement in solar energy collection and additional drag associated with asymmetric flight. A mission model with a focus on …

Design, Analysis, And Simulation Of A Jitter Reduction Circuit (Jrc) System At 1ghz, Run Bin Yu

Master's Theses

The clock signal is considered as the “heartbeat” of a digital system yet jitter which is a variation on the arrival time of the clock edge, could undermine the overall performance or even cause failures on the system. Deterministic jitter could be reduced during the designing process however random jitter during operation is somehow less-controllable and unavoidable. Being able to remove jitter on the clock would therefore play a vital role in system performance improvement.

This thesis implements a 1GHz fully feedforward jitter reduction circuit (JRC) which can be used as an on-chip IP core at clock tree terminals to …

Evaluation Of Efficiency Of Various Materials To Shield From Radiation In Space Using The Monte Carlo Transport Code Called Fluka, Roman Savinov

Master's Theses

The purpose of this study is to improve spacecraft shielding from radiation in space. It focuses on the evaluation of shielding efficiency of different materials. The efficiency of a shield is evaluated by the dose profile within the shield and the amount of dose absorbed by a target using the Monte Carlo transport code called FLUKA. The output of this code is validated by recreating the experiments from published papers and comparing the results. Once the FLUKA’s output is validated, the efficiency of sixteen materials, subject to SPE and GCR sources, are evaluated. The efficiency comparison is made by fixing …

Field Emissions Of (Hydro)Chlorofluorocarbons And Methane From A California Landfill, Alexander H. Sohn

Master's Theses

A comprehensive field investigation was conducted at Potrero Hills Landfill (PHL) located in Suisun City, California to quantify emissions of twelve (hydro)chlorofluorocarbons (i.e. F-gases). The specific target constituents for this study included CFC-11, CFC-12, CFC-113, CFC-114, HCFC-21, HCFC-22, HCFC-141b, HCFC-142b, HCFC-151a, HFC-134a, HFC-152a, and HFC-245fa. The majority of the F-gas emission studies have been conducted outside of the United States and very limited field landfill emission data are available in the United States. Because of historical usage of blowing agents in insulation foams including CFC-11, HCFC-142b, HFC-134a, and HFC-245fa, models reported in literature predicted high F-gas emissions from a landfill …

Native Cryptography In The Browser, An Exploratory Approach, Joseph A. Wilson

Master's Theses

As applications move from the desktop to the web browser, security needs to be taken into consideration. The new Web Crypto API provides native support for web applications to perform cryptographic operations and key management functions. Client side cryptographic support is a critical component in the future development of secure web based applications. This thesis presents an exploration of the Web Crypto API. The aim of this research was to determine the feasibility of developing complex cryptographic applications in the browser. This evaluation was performed by building an end to end encrypted messaging system that implements the off the record …

Effect Of Oxygen-Limiting Tidal Conditions On Muscle Metabolism And Structure In The Giant Acorn Barnacle, Balanus Nubilus, Katie O. Grady

Master's Theses

Crustacean muscle fibers are some of the largest cells in the animal kingdom, with fiber diameters in the giant acorn barnacle (Balanus nubilus) exceeding 3 mm. Sessile animals with extreme muscle sizes and that live in the hypoxia-inducing intertidal zone – like B. nubilus – represent ideal models for probing the effects of oxygen limitation on muscle cells. We investigated changes in metabolism and structure of B. nubilus muscle in response to: normoxic immersion, anoxic immersion, or air emersion, for acute (6h) or chronic (6h exposures twice daily for 2wks) time periods. Following exposure, we immediately measured hemolymph …

An Introduction To Boolean Algebras, Amy Schardijn

Electronic Theses, Projects, and Dissertations

This thesis discusses the topic of Boolean algebras. In order to build intuitive understanding of the topic, research began with the investigation of Boolean algebras in the area of Abstract Algebra. The content of this initial research used a particular notation. The ideas of partially ordered sets, lattices, least upper bounds, and greatest lower bounds were used to define the structure of a Boolean algebra. From this fundamental understanding, we were able to study atoms, Boolean algebra isomorphisms, and Stone’s Representation Theorem for finite Boolean algebras. We also verified and proved many properties involving Boolean algebras and related structures.

We …

Regular Round Matroids, Svetlana Borissova

Electronic Theses, Projects, and Dissertations

A matroid M is a finite set E, called the ground set of M, together with a notion of what it means for subsets of E to be independent. Some matroids, called regular matroids, have the property that all elements in their ground set can be represented by vectors over any field. A matroid is called round if its dual has no two disjoint minimal dependent sets. Roundness is an important property that was very useful in the recent proof of Rota's conjecture, which remained an unsolved problem for 40 years in matroid theory. In this thesis, we …

Bio-Mathematics: Introduction To The Mathematical Model Of The Hepatitis C Virus, Lucille J. Durfee

Electronic Theses, Projects, and Dissertations

In this thesis, we will study bio-mathematics. We will introduce differential equations, biological applications, and simulations with emphasis in molecular events. One of the first courses of action is to introduce and construct a mathematical model of our biological element. The biological element of study is the Hepatitis C virus. The idea in creating a mathematical model is to approach the biological element in small steps. We will first introduce a block (schematic) diagram of the element, create differential equations that define the diagram, convert the dimensional equations to non-dimensional equations, reduce the number of parameters, identify the important parameters, …

A Study Of The Static Bicycle Reposition Problem With A Single Vehicle, Ling Zu

All Dissertations

The Bicycle Sharing System (BSS), a public service system operated by the government or a private company, provides the convenient use of a bicycle as a temporary method of transportation. More specifically, this system allows people to rent a bike from one location, use it for a short time period and then return it to either to the same or a different location for an inexpensive fee. With the development of IT technology in the 1990s, it became possible to balance the bicycle inventory among the various destinations. In fact, a critical aspect to maintaining a satisfactory BSS is effectively …

Physics-Based Models For Engine System Studies: Quasi-D Dual-Fuel Combustion And Real-Time Intake Charge Flow Estimation, Shuonan Xu

All Dissertations

Ever tightening emissions and fuel economy regulations provide a strong impetus for research on high-efficiency low-emission engine concepts. In addition, CO2 emission regulation and energy security considerations motivate investigations focused on alternative fuels. In the current heavy-duty fleet, diesel engines dominate the market due to their unmatched thermal efficiency. Nevertheless, they suffer from NOx and soot emissions and require complex aftertreatment systems to meet stringent regulations. Due to recent advancements of the Natural Gas (NG) extraction technology, its supply has become increasingly abundant. Conversion of Heavy Duty engines to NG operation provides a most effective way of increasing utilization of …

Gravitation And Cosmology With York Time, Philipp Roser

All Dissertations

Despite decades of inquiry an adequate theory of 'quantum gravity' has remained elusive, in part due to the absence of data that would guide the search and in part due to technical difficulties, prominently among them the 'problem of time'. The problem is a result of the attempt to quantise a classical theory with temporal reparameterisation and refoliation invariance such as general relativity. One way forward is therefore the breaking of this invariance via the identification of a preferred foliation of spacetime into parameterised spatial slices. In this thesis we argue that a foliation into slices of constant extrinsic curvature, …

Evaluating Indirect Calorimetry Methodology, Postural Energy Expenditure, And The Effects Of Diet And Exercise Recommendations, Collin Jeffrey Popp

All Dissertations

Scientific research provides the evidence necessary to build an effective framework for health recommendations. In a population of young, healthy adults the recommended duration of an indirect calorimetry measurement period when measuring resting energy expenditure was a minimum of 10 minutes, with the first 5-minutes being discarded. A steady state period was achieved during the second 5-minute segment of a 30-minute period. Furthermore, in a population of young women, short-term standing energy expenditure was statically greater than lying and sitting energy expenditure. However, recommendations to stand instead of sit may be negligible as the magnitude of the effect of short-term …

Affordance-Based Design Product Evolution Using Customer Feedback, Ivan Mata

All Dissertations

Designers can benefit from involving the user in the product development process. Understanding how users perceive products can help designers make decisions that better accommodate user needs. Though several methods have been created that involve the user at different stages of the design process, there is still no clear connection between user perceptions and product improvements. Affordance Based Design (ABD) provides the theoretical background needed to explore such connections. ABD is a systematic de-sign method that uses the concept of affordances to describe the interactions between users and products. The integration of ABD and genetic algorithms (GAs) is proposed as …

Evaluation Of 1,4-Dioxane Biodegradation Under Aerobic And Anaerobic Conditions, Francisco J. Barajas Rodriguez

All Dissertations

Used mainly as a solvent stabilizer, 1,4-dioxane is present at many sites contaminated along with chlorinated solvents and other chemical compounds. Considered a probable human carcinogen by the U.S. Environmental Protection Agency, this contaminant has raised considerable concerns because of its potential adverse effects on health. Therefore, remediation of 1,4-dioxane has gained importance, and although there are several approaches for its treatment, such as ex situ physicochemical processes, bioremediation is a key alternative because it is a low energy demanding process. Anaerobic conditions are present at most contaminated sites, however, there is insufficient scientific evidence for anaerobic biodegradation of 1,4-dioxane. …

Analysis Of High Pressure H2/O2, H2/Air And Kerosene/Air Reacting Shear Flows, Ayse Korucu

All Dissertations

Direct Numerical Simulation (DNS) data for high pressure H₂/O₂ and H₂/Air flames using the compressible flow formulation, detailed kinetics, a real fluid equation of state, and generalized diffusion are analyzed. The DNS is filtered over a range of filter widths to provide exact terms in the Large Eddy Simulation (LES) governing equations, including unclosed terms. The filtered heat flux vector is extensively compared with the heat flux vector calculated as a function of the filtered primitive variables (i.e. the exact LES term is compared with its form available within an actual LES). The difference between …

Report On The Condition Trend Of The Western Australian Pastoral Resource Base 2016, Andrew Watson, Philip Thomas

Natural resources published reports

Consistent with the Pastoral Lands Board’s (PLB) direction, data and analyses are reported at the Land Conservation District (LCD) scale. Some caution is urged when interpreting the report as this summary data may mask the variation in condition evident on leases within an LCD.

In the Kimberley, the analyses of the WARMS point data suggest that the trend in rangeland condition indicated by the frequency of desirable perennial grasses is stable. This is consistent with previous recent reports. However, the analyses of MODIS satellite plant cover data and greenness response indicated by NDVI, suggest areas of the Derby – West …

Supporting Diverse Learners Through Professional Learning For Teachers, Ashley Newman Winnen

Dissertations

School leaders use professional learning practices as a strategy to improve teaching and therefore student learning. As student populations become more ethnically and socioeconomically diverse, teachers need ongoing training to meet the needs of today’s students. One successful elementary school in Colorado was the focus of this case study designed to identify the professional learning practices of a school with a record of closing the achievement gap with a high Latino population and a high percentage of students living in poverty. It was found that professional learning is strongly rooted in the culture and structures of Owl Crest Elementary School …

Social-Cognitive Influences Regarding Persistence And Achievement Of Nontraditional Students In Higher Education, Kristy Renee Dykema

Dissertations

Due to a variety of factors, there has been an increase in nontraditional students enrolling in higher education. However, little information is available on how nontraditional students experience higher education and the unique barriers and supports they experience. Additionally, the current literature on nontraditional students is limited as many previous studies use age as the sole criterion for nontraditional status; recent research suggests these students fit a broader definition of variables beyond age. The purpose of this study was to utilize a sequential mixed-methods approach to investigate the characteristics of students (n = 236) at a local community college, their …

Vector Magneto-Optical Generalized Ellipsometry For Determining Magneto-Optical Properties Of Thin Films, Chad Briley

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Modern growth techniques allow for highly complex nano scale thin films to be created. These new films possess highly anisotropic properties structurally, optically, and magnetically that are significantly different from that of their bulk counterparts and must be accurately characterized in order to optimize desired properties for applications in next generation devices. Current magnetometry techniques focus on high symmetry characterization, namely in and out of the sample plane, and therefore do not possess the capabilities to fully explore these anisotropic properties without complicated setups and multiple sample manipulations. The author describes a setup that combines generalized ellipsometry with an octu-pole …

Diversity Education: Are We Preparing Teachers To Teach All Learners?, Lindi Andreasen

Undergraduate Honors Capstone Projects

Five hundred twenty-three preservice teachers from six different preparation programs completed the diversity and multicultural perspectives portion of the Professional Teaching Knowledge and Skills Survey (PTKSS) to determine their feelings of multicultural efficacy at the end of their program and again after their first year of teaching. Statistical analysis revealed that preservice teachers rate their capability to teach diverse students as "adequate" to "well" on a 5 point Likert type scale (M=35.28, possible Range=0-50), with no significant drop in self-efficacy after one year of teaching (M=34.09). However, individual item means did drop consistently between the preservice and inservice stages, and …

The Science And Religion Relationship, Keeley Samsonik

Verbum

In lieu of an abstract, below is the essay's first paragraph.

"The widely known debate of science and religion has been around for hundreds of years. This is a widely conflicted debate because it is hard to separate both sides. Though it is easy to see that science and religion explain problems differently. Science answers questions by explaining how and religion wonders why. My thesis is that science and religion contrast each other but also can complement one another and it is important to recognize this."

Developing Academic Literacy: What Novice Teachers Can Learn From The Case Of Teaching Latino/Bilingual Learners Science And Mathematics, Sandra I. Musanti, Sandra Mercuri

Bilingual and Literacy Studies Faculty Publications

No abstract provided.

Adaptive Background Modeling With Temporal Feature Update For Dynamic Foreground Object Removal, Li Yin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis explores several approaches in order to develop an effective algorithm for separating the moving objects from the background so that the background alone may be displayed in a video sequence. In particular, this thesis seeks to develop an algorithm that can successfully remove a moving teacher from the whiteboard, so that the writing on the whiteboard may be fully visible to the audience.

In this thesis, some prior works related to this problem are studied to understand the basic principles of adaptive background modeling, or removing the foreground from a background with occasional changes in a video sequence. …

Laboratory Experiences In Mathematical Biology For Post-Secondary Mathematics Students, Matthew Lewis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In addition to the memorization, algorithmic skills and vocabulary which is the default focus in many mathematics classrooms, professional mathematicians are expected to creatively apply known techniques, construct new mathematical approaches and communicate with and about mathematics. We propose that students can learn these professional, higher level skills through Laboratory Experiences in Mathematical Biology (LEMBs) which put students in the role of mathematics researcher creating mathematics to describe and understand biological data. LEMBs are constructed so they require no specialized equipment and can easily be run in the context of a college math class. Students collect data and develop mathematical …

Statistical Techniques To Model And Optimize Performance Of Scientific, Numerically Intensive Workloads, Steena Dominica Steven Monteiro

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Projecting performance of applications and hardware is important to several market segments—hardware designers, software developers, supercomputing centers, and end users. Hardware designers estimate performance of current applications on future systems when designing new hardware. Software developers make performance estimates to evaluate performance of their code on different architectures and input datasets. Supercomputing centers try to optimize the process of matching computing resources to computing needs. End users requesting time on supercomputers must provide estimates of their application’s run time, and incorrect estimates can lead to wasted supercomputing resources and time. However, application performance is challenging to predict because it is …

Inequalities Of Hardy-Littlewood-Polya Type For Functions Of Operators And Their Applications, Vladyslav Babenko, Yuliya Babenko, Nadiia Kriachko

Faculty Articles

In this paper, we derive a generalized multiplicative Hardy-Littlewood-Polya type inequality, as well as several related additive inequalities, for functions of operators in Hilbert spaces. In addition, we find the modulus of continuity of a function of an operator on a class of elements defined with the help of another function of the operator. We then apply the results to solve the following problems: (i) the problem of approximating a function of an unbounded self-adjoint operator by bounded operators, (ii) the problem of best approximation of a certain class of elements from a Hilbert space by another class, and (iii) …