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Articles 1291 - 1320 of 3436

Full-Text Articles in Physical Sciences and Mathematics

The Calculation Of H-Beta Indices For Delta Scuti Variable Stars, Kelsey Jorgenson, Dr. Eric Hintz Apr 2014

The Calculation Of H-Beta Indices For Delta Scuti Variable Stars, Kelsey Jorgenson, Dr. Eric Hintz

Journal of Undergraduate Research

A large part of astronomical research involves gathering information about celestial objects and drawing conclusions about that information. Astronomers commonly gather data for research projects via sweeping surveys, either of particular regions of the sky or of specific kinds of stars or celestial objects. Data from these surveys are often arranged into catalogues. The aim of my research project was to fill in information gaps in the catalogue of information of known delta Scuti variable stars, particularly in the form of the hydrogen beta, or H-beta, index. I will give introductory information about delta Scuti stars as well as the …

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Lithium-6 Neutron Detector, Adam Wallace, Dr. Lawrence Rees Apr 2014

Lithium-6 Neutron Detector, Adam Wallace, Dr. Lawrence Rees

Journal of Undergraduate Research

Over the last year I have built several neutron detectors with lithium-6 glass and tested their efficiency. As stated in my proposal, this detector is being designed for use by the United States Department of Homeland Security (DHS) at portal monitors. In order to meet their requirements we had to test our detectors for neutron detection efficiency and minimize their sensitivity to gamma radiation.

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Up Congruences Of Modular Functions Modulo Powers Of Primes, Michael Griffin, Dr. Paul Jenkins Apr 2014

Up Congruences Of Modular Functions Modulo Powers Of Primes, Michael Griffin, Dr. Paul Jenkins

Journal of Undergraduate Research

Modular forms are constructs of complex analysis that possess many intricate connections to widely-separated branches of mathematics. In the most well-known application of these functions, Andrew Wiles established a connection between the Fourier coefficients of modular forms and elliptic curves–objects of analytic geometry–in order to prove Fermat’s Last Theorem, a classical number theory problem that had resisted proof for more than 350 years. Modular forms have also found applications ranging from cryptography to the million-dollar Birch and Swinerton-Dyer conjecture.

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Investigation Of Investor-Manager Conflict In Mutual Funds Using Dynamic Models, Jeremiah Bejarano, Dr. Jeffrey Humpherys Apr 2014

Investigation Of Investor-Manager Conflict In Mutual Funds Using Dynamic Models, Jeremiah Bejarano, Dr. Jeffrey Humpherys

Journal of Undergraduate Research

In this project, my goal was to analyze the relation between marketshare incentives and risk taking in the hedge fund industry. Using the techniques of stochastic optimal control or dynamic programming, as applied in the typical Continuous-Time Consumption and Portfolio Choice model, I worked to develop a mathematical model to explore the effects of management fees and performance bonuses as well as the effects of changing market share on the fund manager’s implicit aversion towards high-risk portfolios. My continuing hypothesis is that due to fundamental differences between the investors and managers incentives, (essentially profit maximization vs. commission maximization) a fund …

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Time Reversal In Non-Idealistic Environments, Blaine Harker, Dr. Kent Gee, Brian Anderson Apr 2014

Time Reversal In Non-Idealistic Environments, Blaine Harker, Dr. Kent Gee, Brian Anderson

Journal of Undergraduate Research

Time reversal is a relatively new type of acoustic localization with many applications, such as lithotripsy to destroy kidney stones, and secure underwater sound communication, though in some ways time reversal is still in the development stage. To this end, we explore the efficiency and limitations of this technique due to the number of sensors used and the directivity pattern of the source to be reconstructed in the experiment.

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Reactivation Of Latent Hiv In Cd4+ T Cells Through Fdc Costimulation, Matthew Greer, Dr. Greg Burton Apr 2014

Reactivation Of Latent Hiv In Cd4+ T Cells Through Fdc Costimulation, Matthew Greer, Dr. Greg Burton

Journal of Undergraduate Research

I received an ORCA grant for a project entitled “Reactivation of latent HIV in CD4+ T cells through FDC costimulation.” The original hypothesis of this research was that the factor FDCs (follicular dendritic cells) produce to reactivate latent HIV in T cells is a protein signaling molecule that can be identified through analyzing the proteins FDCs produce. While this project is still proceeding, my resources during the last year since I received an ORCA grant have been dedicated to ironing out a few preliminary wrinkles to this project. Specifically, I have troubleshot and optimized the method our lab group uses …

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Analysis Of The Kinetics Of Atmospherically Important Reactions, Marie Killian Chilton, Dr. Jaron Hansen Apr 2014

Analysis Of The Kinetics Of Atmospherically Important Reactions, Marie Killian Chilton, Dr. Jaron Hansen

Journal of Undergraduate Research

Organic peroxy radicals react to form tropospheric ozone, which harms the health of humans and vegetation and is considered the most significant pollutant in rural areas.1 Many of the individual reactions in the overall mechanism for ozone formation involve radicals. Radicals are highly reactive and therefore it is challenging to measure their fundamental properties directly. Particularly, it is difficult to determine an accurate reaction rate constant for reactions involving radicals. This rate constant is largely dependent on the atmospheric conditions. Dr. Jaron Hansen is currently studying the effect of water vapor on the kinetic rate constant for the reaction of …

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Sat-Driven Prime Factorization, Chris Dalton, Dr. Dan Ventura Apr 2014

Sat-Driven Prime Factorization, Chris Dalton, Dr. Dan Ventura

Journal of Undergraduate Research

Prime factorization is the breaking down of a composite number into prime numbers that, when multiplied together, equal the number. There is not a known algorithm that accomplishes this task in sub-exponential time. For my ORCA project, I worked with Dr. Dan Ventura and sought to develop a polynomial-time prime factorization algorithm. The development of such an algorithm would have revolutionized computer security and oered new insight to even more di‑cult problems. I rst approached the task as a boolean constraint satisfaction problem, but after running out of ideas, I tried coming at it from a more number theoretic standpoint. …

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Establishing The Theoretical Relationship Between Bayesian Inference And Dynamical Structure Functions For Network Reconstruction, Julius Adebayo, Dr. Sean Warnick Apr 2014

Establishing The Theoretical Relationship Between Bayesian Inference And Dynamical Structure Functions For Network Reconstruction, Julius Adebayo, Dr. Sean Warnick

Journal of Undergraduate Research

A system-level understanding of the functioning behavior of a cell requires an accurate representation of the underlying networks of gene and protein interactions. Network reconstruction is an area of systems biology that attempts to reconstruct the network of regulatory interactions from available measurements using a mathematical framework. Developing a theoretical relationship between Bayesian inference methods and dynamical structure functions is an important first step in developing unique qualitative processes that correctly infer network structures [1], [3].

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Genetic Rescue Of The Irk 2 Knockout Phenotype By Ectopic Expression Of Irk 2 Wt, Brandon Gassaway, Dr. Emily Bates Apr 2014

Genetic Rescue Of The Irk 2 Knockout Phenotype By Ectopic Expression Of Irk 2 Wt, Brandon Gassaway, Dr. Emily Bates

Journal of Undergraduate Research

Anderson-Tawil Syndrome (ATS) is characterized by morphological defects including clinodactyly (abnormal curvature of digits), syndactyly (fused digits), micrognathia (small jaw), cleft palate, and hypertelorism (wide-set eyes) as well as periodic paralysis and heart arrhythmia. Mutations in inwardly rectifying potassium (Irk) channels are found in patients with ATS. Expression of mutant Irk channels causes similar physiological and morphological defects in mice.1

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Smoking And Tuberculosis In Ukraine, Noel Ellison, Dr. Bruce Collings Apr 2014

Smoking And Tuberculosis In Ukraine, Noel Ellison, Dr. Bruce Collings

Journal of Undergraduate Research

Tuberculosis (TB) is a contagious bacterial infection caused by mycobacterium Tuberculosis. While some people consider TB to be a “dead” disease that was eradicated years ago, it is, in fact, very much alive in the world today. It is estimated that more than two billion people are infected with TB bacilli1; this is approximately one third of the world’s population. There are many factors associated with the development of TB. Previous research links socioeconomic factors as well as HIB-TB co-infection with the TB epidemic. Countries that are poorer and have higher levels of HIV tend to have more cases of …

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The Total Synthesis Of S-Equol Using Phase Transfer Catalysis, Eric Bready, Dr. Merritt Andrus Apr 2014

The Total Synthesis Of S-Equol Using Phase Transfer Catalysis, Eric Bready, Dr. Merritt Andrus

Journal of Undergraduate Research

The purpose of this project was completion of the total organic synthesis of the anti-cancer compound (S)-equol. My goal was to carry out our planned synthesis of this molecule using Phase Transfer Catalysts, (PTCs), which promote the formation of the S enantiomer as opposed to the R enantiomer of equol (S and R enantiomers are like right and left hands, which are mirror images of each other—in organic synthesis usually only one form is desired) (1). In using PTCs it was our hope that we would be able to form (S)-equol with high yield and in a timely manner. Successful …

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Synthesis Of S-Equol Using Heck Coupling Reaction And Phase-Transfer Catalysis, Chelsey Hancock Apr 2014

Synthesis Of S-Equol Using Heck Coupling Reaction And Phase-Transfer Catalysis, Chelsey Hancock

Journal of Undergraduate Research

Please list all accomplishments, achievements, publications, presentations, or other scholarly productivity that resulted from your ORCA project. This may include submissions to peer-reviewed journals, conference presentations or papers, performances, exhibitions, internships, scholarships, graduate school opportunities, local presentations, or awards that followed your mentoring experience.

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Making Systems Users Accountable Through User Interface Design Features, Lee Wood, Dr. Anthony Vance Apr 2014

Making Systems Users Accountable Through User Interface Design Features, Lee Wood, Dr. Anthony Vance

Journal of Undergraduate Research

The purpose of this research was to determine how features of the user interface of an information system could be designed to increase users’ perceptions of accountability within the system, and thereby decrease levels of unauthorized access. One of the most persistent problems of information security is the threat of malicious insiders, or members of an organization who misuse access to information resources. The Verizon 2010 Data Breach Investigations Report disclosed that 48 percent of data breaches were attributable to unauthorized access by organizational insiders (Verizon, 2010). This means that nearly half of data breaches come not from compromised systems, …

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Ensemble Methods For Historical Machine-Printed Document Recognition, William B. Lund Apr 2014

Ensemble Methods For Historical Machine-Printed Document Recognition, William B. Lund

Theses and Dissertations

The usefulness of digitized documents is directly related to the quality of the extracted text. Optical Character Recognition (OCR) has reached a point where well-formatted and clean machine- printed documents are easily recognizable by current commercial OCR products; however, older or degraded machine-printed documents present problems to OCR engines resulting in word error rates (WER) that severely limit either automated or manual use of the extracted text. Major archives of historical machine-printed documents are being assembled around the globe, requiring an accurate transcription of the text for the automated creation of descriptive metadata, full-text searching, and information extraction. Given document …

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In Vitro Activation Of Human Follicular Dentritic Cells And Its Effects On Human Immunodeficiency Virus Infection, Sean Llewellyn, Dr. Gregory F. Burton Apr 2014

In Vitro Activation Of Human Follicular Dentritic Cells And Its Effects On Human Immunodeficiency Virus Infection, Sean Llewellyn, Dr. Gregory F. Burton

Journal of Undergraduate Research

HIV is known to survive on follicular dendritic cells (FDCs) for many months and is believed to contribute to persisting HIV infection. FDCs protect HIV from degradation, thereby prolonging the infectivity of the virus. Moreover, when virus is trapped on FDCs, it escapes the ability of neutralizing antibodies (NtAb) to block infection of CD4+ T cells and subsequent removal of virus from the body. We postulate that FDC CD32 and/or CD21 contribute to maintaining virus infectivity and permitting infection in the presence of NtAb. Furthermore, when HIV forms an immune complex with antibodies and binds to CD32 and/or CD21, the …

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The Roles Of Phosducin-Like Protein 1 And Programmed Cell Death Protein 5 As Molecular Co-Chaperones Of The Cytosolic Chaperonin Complex, Christopher M. Tracy Apr 2014

The Roles Of Phosducin-Like Protein 1 And Programmed Cell Death Protein 5 As Molecular Co-Chaperones Of The Cytosolic Chaperonin Complex, Christopher M. Tracy

Theses and Dissertations

A fundamental question in biology is how proteins, which are synthesized by the ribosome as a linear sequence of amino acids, fold into their native functional state. Many proteins require the assistance of molecular chaperones to maneuver through the folding process to protect them from aggregation and to help them reach their native state in the very concentrated protein environment of the cell. This study focuses on the roles of Phosducin-like Protein 1 (PhLP1) and Programmed Cell Death Protein 5 (PDCD5) as molecular co-chaperones of the Cytosolic Chaperonin Complex (CCT).Signaling in retinal photoreceptors is mediated by canonical G protein pathways. …

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Orca Final Report, Michael Christensen Mar 2014

Orca Final Report, Michael Christensen

Journal of Undergraduate Research

BYU’s Fulton Supercomputing Lab (FSL) is a centralized campus resource whose mission is “to facilitate and enhance computationally-intensive research at BYU by providing reliable, state-of-the-art, high performance computing resources to faculty and students.” As part of that mission, Supercomputing provides large compute clusters and other systems for researchers to use as needed. If a researcher needs to do computationally intensive research that wouldn’t be feasible on a standard desktop, they can submit batch processing jobs to the lab’s systems and get their work done in a fraction of the time. A researcher’s code is then run in parallel on many …

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Comparative Sedimentology Of Lake Bonneville And The Great Salt Lake, Kevin Michael Mcguire Mar 2014

Comparative Sedimentology Of Lake Bonneville And The Great Salt Lake, Kevin Michael Mcguire

Theses and Dissertations

Ooids of Great Salt Lake, Utah (GSL) have been studied periodically by geologists since the 1960's. These studies have documented the locations of ooid deposits, bulk composition, mineralogy, and internal structural variations of GSL ooids. Ooids have also been identified in sediment cores from lakes predating the Great Salt Lake, but similar descriptions have not been made for these ooids. Samples of ooids from cores in Pilot Valley, UT/NV and Knolls, UT have been obtained, along with samples from the Great Salt Lake at Bridger Bay and Rozel Point. The cortical fabrics and crystal morphologies of these ooids were studied …

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Spin And Orbital Moments And Magnetic Order In Fe3o4 Nanoparticle Assemblies, Yanping Cai Mar 2014

Spin And Orbital Moments And Magnetic Order In Fe3o4 Nanoparticle Assemblies, Yanping Cai

Theses and Dissertations

Fe3O4 magnetic nanoparticles of 5 to 11 nm in size were prepared by organic methods. Particle size was analyzed by both X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) techniques. Zero Field Cooling (ZFC) / Field Cooling (FC) and magnetization loop measurements were recorded by VSM, and they confirmed superparamagnetic behavior in the sample. The blocking temperature is found to be in the range of 30 K ~ 170 K. It has a dependence on the particle size. ZFC / FC curves also indicate the presence of magnetic coupling between particles. X-ray Magnetic Circular Dichroism (XMCD) measurements of these nanoparticles …

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Estimating The Acoustic Power Of Sources In Nonideal Enclosures Using Generalized Acoustic Energy Density, Daniel Ryan Marquez Mar 2014

Estimating The Acoustic Power Of Sources In Nonideal Enclosures Using Generalized Acoustic Energy Density, Daniel Ryan Marquez

Theses and Dissertations

Sound power measurements of acoustic sources are generally made in reverberation or anechoic chambers using acoustic pressure measurements as outlined in specific ISO or other standards. A reverberation chamber produces an approximate diffuse-field condition, wherein the sound power is determined from the spatially averaged squared pressure. An anechoic chamber produces an approximate free-field condition, wherein the sound power is estimated from squared pressure over an enveloping measurement surface. However, in many cases it is desirable to estimate sound power within nonideal semi-reverberant spaces. In these environments, both direct and reverberant energies may contribute significantly to the total acoustic field. This …

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Desorption Electrospray Ionization Mass Spectrometry Imaging: Instrumentation, Optimization And Capabilities, Manan Dhunna Mar 2014

Desorption Electrospray Ionization Mass Spectrometry Imaging: Instrumentation, Optimization And Capabilities, Manan Dhunna

Theses and Dissertations

Desorption Electrospray Ionization Mass spectrometry Imaging (DESI-MSI) is an area of great interest and a promising tool in the field of chemical imaging. It is a powerful, label-free technique, which can determine, map and visualize different molecular compounds on a sample surface. The amount of information acquired in a single DESI-MSI experiment is enormous compared to other techniques, as it can simultaneously detect different compounds with their spatial distribution on the surface. The experiment can be used to produce two-dimensional and three-dimensional images. Chapter 2 focuses on the design and optimization of the setup for performing DESI-MS imaging on various …

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Facile Synthesis And Characterization Of A Thermally Stable Silica-Doped Alumina With Tunable Surface Area, Porosity, And Acidity, Maryam Khosravi Mardkhe Mar 2014

Facile Synthesis And Characterization Of A Thermally Stable Silica-Doped Alumina With Tunable Surface Area, Porosity, And Acidity, Maryam Khosravi Mardkhe

Theses and Dissertations

Mesoporous γ-Al2O3 is one of the most widely used catalyst supports for commercial catalytic applications. The performance of a catalyst strongly depends on the combination of textural, chemical and physical properties of the support. Pore size is essential since each catalytic system requires a unique pore size for optimal catalyst loading, diffusion and selectivity. In addition, high surface area and large pore volume usually result in higher catalyst loading, which increases the number of catalytic reaction sites and decreases reaction time. Therefore, determination of surface area and porosity of porous supports is critical for the successful design and optimization of …

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Pwm: A Secure Webmail System Designed For Easy Adoption, Benjamin W. Burgon Mar 2014

Pwm: A Secure Webmail System Designed For Easy Adoption, Benjamin W. Burgon

Theses and Dissertations

None of the three largest webmail service providers (serving over 1 billion users) support end-to-end message encryption. Encrypted email has never seen mass adoption because it is prohibitive for non-experts to use. Private WebMail (Pwm) is our extension to popular webmail systems that lets users easily encrypt sensitive messages without having to first contact the recipient and share information. It is designed to spread quickly in a grassroots fashion so that a user receiving their first encrypted message can quickly and easily start using the system. This thesis describes the design and implementation of Pwm, then measures its usability through …

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Multivariate Factor Analysis Of A Rocky Mountain Lichen Set, S. Aaron Ross, Dr. Nolan F. Mangelson Mar 2014

Multivariate Factor Analysis Of A Rocky Mountain Lichen Set, S. Aaron Ross, Dr. Nolan F. Mangelson

Journal of Undergraduate Research

Lichens are a symbiotic relationship between a fungus and an alga. They have no root system, so although they grow off rocks and trees, they need to gather their nutrients from the air. Their great dependence on the atmosphere makes them very susceptible to changes in the air. For instance, a high ambient level of pollution particulates could cause the lichens to collect an increased amount of those particles. Because of this sensitivity to the environment, lichens have become a focus point of scientists to determine ambient pollution levels.1

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Managing Autonomy By Hierarchically Managing Information: Autonomy And Information At The Right Time And The Right Place, Rongbin Lin Mar 2014

Managing Autonomy By Hierarchically Managing Information: Autonomy And Information At The Right Time And The Right Place, Rongbin Lin

Theses and Dissertations

When working with a complex AI or robotics system in a specific application, users often need to incorporate their special domain knowledge into the autonomous system. Such needs call for the ability to manage autonomy. However, managing autonomy can be a difficult task because the internal mechanisms and algorithms of the autonomous components may be beyond the users' understanding. We propose an approach where users manage autonomy indirectly by managing information provided to the intelligent system hierarchically at three different temporal scales: strategic, between-episodes, and within-episode. Information management tools at multiple temporal scales allow users to influence the autonomous behaviors …

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Nascent Peptides That Induce Translational Arrest, Christopher J. Woolstenhulme Mar 2014

Nascent Peptides That Induce Translational Arrest, Christopher J. Woolstenhulme

Theses and Dissertations

Although the ribosome is a very general catalyst, it cannot synthesize all protein sequences equally well. Certain proteins are capable of stalling the ribosome during their own synthesis. Stalling events are used by both prokaryotic and eukaryotic cells to regulate gene expression. Characterization of natural stalling peptides shows that only a few strategically placed amino acids are needed to inactivate the ribosome. These motifs share little sequence similarity suggesting that there are more stalling motifs yet to be discovered. Here we use two genetic selections in E. coli to discover novel stalling peptides and detail their subsequent characterization. Kinetic studies …

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A Volume Bound For Montesinos Links, Kathleen Arvella Finlinson Mar 2014

A Volume Bound For Montesinos Links, Kathleen Arvella Finlinson

Theses and Dissertations

The hyperbolic volume of a knot complement is a topological knot invariant. Futer, Kalfagianni, and Purcell have estimated the volumes of Montesinos link complements for Montesinos links with at least three positive tangles. Here we extend their results to all hyperbolic Montesinos links.

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West Antarctic Surface Mass Balance: Do Synoptic Scale Modes Of Climate Contribute To Observed Variability?, Mclean Kent Carpenter Mar 2014

West Antarctic Surface Mass Balance: Do Synoptic Scale Modes Of Climate Contribute To Observed Variability?, Mclean Kent Carpenter

Theses and Dissertations

Western Antarctica has been experiencing significant warming for at least the past fifty years. While higher Net Surface Mass Balance (SMB) over West Antarctica during this period of warming is expected, SMB reconstructions from ice cores reveal a more complex pattern during the period of warming. The mechanisms giving rise to SMB variability over the West Antarctic Ice Sheet (WAIS) are not well understood due to lack of instrumental data. The Southern Annular Mode (SAM) and El Niño Southern Oscillation (ENSO) are believed to contribute to WAIS SMB variability but the assumption has not been rigorously tested. SMB during years …

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The Minimum Rank Of Schemes On Graphs, William Nelson Sexton Mar 2014

The Minimum Rank Of Schemes On Graphs, William Nelson Sexton

Theses and Dissertations

Let G be an undirected graph on n vertices and let S(G) be the class of all real-valued symmetric n × n matrices whose nonzero off-diagonal entries occur in exactly the positions corresponding to the edges of G. Let V = {1, 2, . . . , n} be the vertex set of G. A scheme on G is a function f : V → {0, 1}. Given a scheme f on G, there is an associated class of matrices Sf (G) = {A ∈ S(G)|aii = 0 if and only if f(i) = 0}. A scheme f is said …

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