Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Brigham Young University

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 5251 - 5280 of 8053

Full-Text Articles in Entire DC Network

Applications Of Variation Analysis Methods To Automotive Mechanisms, Robert C. Leishman Jun 2009

Applications Of Variation Analysis Methods To Automotive Mechanisms, Robert C. Leishman

Theses and Dissertations

Variation analysis, or tolerance analysis as it is sometimes called, is typically used to predict variation in critical dimensions in assemblies by calculating the stack-up of the contributing component variations. It is routinely used in manufacturing and assembly environments with great success. Design engineers are able to account for the small changes in dimensions that naturally occur in manufacturing processes, in equipment, and due to operators and still ensure that the assemblies will meet the design specifications and required assembly performance parameters. Furthermore, geometric variation not only affects critical fits and clearances in static assemblies, it can also cause variation …

Go to article

Improving The Separability Of A Reservoir Facilitates Learning Transfer, David Norton, Dan A. Ventura Jun 2009

Improving The Separability Of A Reservoir Facilitates Learning Transfer, David Norton, Dan A. Ventura

Faculty Publications

We use a type of reservoir computing called the liquid state machine (LSM) to explore learning transfer. The Liquid State Machine (LSM) is a neural network model that uses a reservoir of recurrent spiking neurons as a filter for a readout function. We develop a method of training the reservoir, or liquid, that is not driven by residual error. Instead, the liquid is evaluated based on its ability to separate different classes of input into different spatial patterns of neural activity. Using this method, we train liquids on two qualitatively different types of artificial problems. Resulting liquids are shown to …

Go to article

Music Recommendation And Query-By-Content Using Self-Organizing Maps, Kyle B. Dickerson, Dan A. Ventura Jun 2009

Music Recommendation And Query-By-Content Using Self-Organizing Maps, Kyle B. Dickerson, Dan A. Ventura

Faculty Publications

The ever-increasing density of computer storage devices has allowed the average user to store enormous quantities of multimedia content, and a large amount of this content is usually music. Current search techniques for musical content rely on meta-data tags which describe artist, album, year, genre, etc. Query-by-content systems allow users to search based upon the acoustical content of the songs. Recent systems have mainly depended upon textual representations of the queries and targets in order to apply common string-matching algorithms. However, these methods lose much of the information content of the song and limit the ways in which a user …

Go to article

Novel Cinchona Alkoloid Derived Ammonium Salts As Phase-Transfer Catalysts For The Asymmetric Synthesis Of Beta-Hydroxy Alpha-Amino Acids Via Aldol Reactions And Total Synthesis Of Celogentin C., Bing Ma Jun 2009

Novel Cinchona Alkoloid Derived Ammonium Salts As Phase-Transfer Catalysts For The Asymmetric Synthesis Of Beta-Hydroxy Alpha-Amino Acids Via Aldol Reactions And Total Synthesis Of Celogentin C., Bing Ma

Theses and Dissertations

Project I. Cinchona alkaloid-derived quaternary ammonium salts have been successfully used as phase-transfer catalysts, particularly in asymmetric alkylations. Our group applied this type of catalyst in the synthesis of β-hydroxy α-amino acids via aldol reactions and discovered that the Park-Jew catalyst afforded good yields and good enantiomeric excess of the syn diasteromers, but negligible diastereoselectivity. This project was therefore focused on the synthesis of novel cinchonidine-derived catalysts with the Park-Jew catalyst as the lead structure. The C3 position of cinchonidine nucleus was modified to achieve dimers and catalysts possessing electron-deficient alkyne and alkene moieties. Synthesized catalysts were tested in the …

Go to article

The Influence Of Risk Taking On Student Creation Of Mathematical Meaning: Contextual Risk Theory, Erin Nicole Houghtaling Jun 2009

The Influence Of Risk Taking On Student Creation Of Mathematical Meaning: Contextual Risk Theory, Erin Nicole Houghtaling

Theses and Dissertations

The primary concerns of mathematics educators are learning and teaching mathematics. It is, therefore, natural to ask "what implications and benefits might there be if learning were perceived as a risk-taking event?" (Atkinson, 1957, p. 266). The underlying motivation of this study is to analyze the risks students take in the mathematics classroom and how risk influences student creation of meaning and development of understanding. I define risk in the mathematics classroom to be any observable act that entails uncertain outcome. The research presented here focuses on a table of four students: Andrew, Carina, Kam, and Mark as they grapple …

Go to article

A Functional Framework For Content Management, Robert Emer Broadbent Jun 2009

A Functional Framework For Content Management, Robert Emer Broadbent

Theses and Dissertations

This thesis proposes a functional framework for content management. This framework provides concepts and vocabulary for analysis and description of content management systems. The framework is derived from an analysis of eight content management systems. It describes forty-five conceptual functions organized into five functional groups. The functionality derived from the analysis of the content management systems is described using the vocabulary provided by the functional framework. Coverage of the concepts in the existing systems is verified. The utility of the framework is validated through the creation of a prototype that implements sufficient functionality to support a set of specific use …

Go to article

Fusion Of The Parastrophic Matrix And Weak Cayley Table, Nathan C. Perry Jun 2009

Fusion Of The Parastrophic Matrix And Weak Cayley Table, Nathan C. Perry

Theses and Dissertations

The parastrophic matrix and Weak Cayley Tables are matrices that have close ties to the character table. Work by Ken Johnson has shown that fusion of groups induces a relationship between the character tables of the groups. In this paper we will demonstrate a similar induced relationship between the parastrophic matrices and Weak Cayley Tables of the fused groups.

Go to article

Heinrich Handschin: Heinrich Wiesner Jun 2009

Heinrich Handschin: Heinrich Wiesner

Swiss American Historical Society Review

I was born on July 1, 1925, in Zeglingen; my father was a small farmer and quarry worker. At the end of Bezirksschule[ corresponds to junior high school with a more demanding curriculum than 5th to 8th grade, at that time it was only found in larger towns] I did not see any possibilities for learning a profession. My teacher decided to send me to teachers' college [Lehrerseminar]. This meant great financial burdens and I needed four different scholarships. The result: I learned for money, not for life. Each trimester I had to appear at the Education …

Go to article

Psychologism And American Instructional Technology, David Wiley, Bekir Gur Jun 2009

Psychologism And American Instructional Technology, David Wiley, Bekir Gur

Faculty Publications

Note: This is not the final draft of the article. The centrality of psychology in the field of instructional technology has never been comprehensively questioned; most instructional technologists have assumed that (behaviorist, cognitivist, constructivist, or another) psychology is the natural foundation for education and thus for instructional technology. The driving question of this article is: What are the problems of psychologism as found in the theories and practices of instructional technology? We present a brief genealogy of American instructional technology in relation to the influence of psychology; review critical psychology and discuss some problems of psychologism focusing on positivism, metaphysics, …

Go to article

Super-Resolution Via Recapture And Bayesian Effect Modeling, Bryan S. Morse, Kevin Seppi, Neil Toronto, Dan A. Ventura Jun 2009

Super-Resolution Via Recapture And Bayesian Effect Modeling, Bryan S. Morse, Kevin Seppi, Neil Toronto, Dan A. Ventura

Faculty Publications

This paper presents Bayesian edge inference (BEI), a single-frame super-resolution method explicitly grounded in Bayesian inference that addresses issues common to existing methods. Though the best give excellent results at modest magnification factors, they suffer from gradient stepping and boundary coherence problems by factors of 4x. Central to BEI is a causal framework that allows image capture and recapture to be modeled differently, a principled way of undoing downsampling blur, and a technique for incorporating Markov random field potentials arbitrarily into Bayesian networks. Besides addressing gradient and boundary issues, BEI is shown to be competitive with existing methods on published …

Go to article

Patterns Of User Activity In The Different Features Of The Blackboard Cms Across All Courses For An Academic Year At Brigham Young University, Michael E. Griffiths, Charles R. Graham Jun 2009

Patterns Of User Activity In The Different Features Of The Blackboard Cms Across All Courses For An Academic Year At Brigham Young University, Michael E. Griffiths, Charles R. Graham

Faculty Publications

In the past decade, course management systems (CMS) have become an integral part of most institutions of higher education. While there has been a significant amount of research looking at CMS usage at the course level, there has been less research looking at the institution-wide CMS usage from a CMS activity database perspective. This article shares findings from a study which analyzes over 36 million student and instructor clicks within the Blackboard CMS across the entire campus of Brigham Young University (BYU) during one full academic year. This research reports overall levels of user activity across campus, patterns of user …

Go to article

Japanese Collections Located Overseas As Interpreted From A Literacy History Perspective, Tsuneharu Gonnami Jun 2009

Japanese Collections Located Overseas As Interpreted From A Literacy History Perspective, Tsuneharu Gonnami

Journal of East Asian Libraries

No abstract provided.

Go to article

The Handschin Foundation: Franz Hasenböhler Jun 2009

The Handschin Foundation: Franz Hasenböhler

Swiss American Historical Society Review

Born on November 1, 1936 as citizen of Therwil near Basel. He attended the elementary school in Therwil and graduated with a Matura [the nationally required exam which allows entering a Swiss (or German, Austrian) university, type A, i.e. with Greek and Latin] from the humanities branch of the Gymnasium [college preparatory school] in Basel in 1956. Subsequently he studied philosophy and law at the universities of Basel and Fribourg and received a doctor in law in 1974.

Go to article

Heinrich Handschin: Wilhelm Mohler Jun 2009

Heinrich Handschin: Wilhelm Mohler

Swiss American Historical Society Review

Mohler, Wilhelm from Thtirnen, born on July 3, 1911, moved in 1916 to Gelterkinden. Parents: Wilhelm and Elise Mohler-Mohler. The father was a watch-maker [Uhrensteinschleifer - grinding a part for watches], after 1916 he worked on the roads in Gelterkinden; the mother was a homemaker and silk-ribbon weaver.

Go to article

What Is Shared? A Framework For Understanding Shared Innovation Within Communities, Richard E. West Jun 2009

What Is Shared? A Framework For Understanding Shared Innovation Within Communities, Richard E. West

Faculty Publications

The 21st century economy often requires the innovative production of conceptual and physical artifacts. These innovations frequently are developed collaboratively within communities of workers. Previous theories about the nature of work and learning within communities have emphasized shared meaning or shared practice, but now shared innovation is required. In this paper, I describe the development of a model for conceptualizing and studying shared innovation within communities. This model was created from merging elements of social learning and creativity/innovation theories. I explain that at an intersection of these two domains is a unique kind of social structure, called a Community of …

Go to article

Dynamics And Control Of Cable-Drogue System In Aerial Recovery Of Micro Air Vehicles Based On Gauss's Principle, Liang Sun, Randal W. Beard, Mark B. Colton, Timothy W. Mclain Jun 2009

Dynamics And Control Of Cable-Drogue System In Aerial Recovery Of Micro Air Vehicles Based On Gauss's Principle, Liang Sun, Randal W. Beard, Mark B. Colton, Timothy W. Mclain

Faculty Publications

This paper presents a new concept for aerial recovery of Micro Air Vehicles (ARMAVs) using a large mothership and a recovery drogue. The mothership drags a drogue attached to a cable and the drogue is controlled to match the flight patten of the MAV. This paper uses Gauss’s Principle to derive the dynamic model of the cable-drogue systems. A controllable drogue plays a key role in recovering MAVs in windy conditions. We develop a control approach for the drogue using its drag coefficient. Simulation results based on multilink cable-drogue systems present the feasibility of the aerial recovery concept and the …

Go to article

An Internal Representation For Adaptive Online Parallelization, Koy D. Rehme May 2009

An Internal Representation For Adaptive Online Parallelization, Koy D. Rehme

Theses and Dissertations

Future computer processors may have tens or hundreds of cores, increasing the need for efficient parallel programming models. The nature of multicore processors will present applications with the challenge of diversity: a variety of operating environments, architectures, and data will be available and the compiler will have no foreknowledge of the environment until run time. Adaptive Online Parallelization (ADOPAR) is a unifying framework that attempts to overcome diver sity by separating discovery and packaging of parallelism. Scheduling for execution may then occur at run time when diversity may best be resolved. This work presents a compact representation of parallelism based …

Go to article

Coalition Robustness Of Multiagent Systems, Nghia Cong Tran May 2009

Coalition Robustness Of Multiagent Systems, Nghia Cong Tran

Theses and Dissertations

Many multiagent systems are environments where distinct decision-makers compete, explicitly or implicitly, for scarce resources. In these competitive environments, itcan be advantageous for agents to cooperate and form teams, or coalitions; this cooperation gives agents strategic advantage to compete for scarce resources. Multiagent systems thus can be characterized in terms of competition and cooperation. To evaluate the effectiveness of cooperation for particular coalitions, we derive measures based on comparing these different coalitions at their respective equilibria. However, relying on equilibrium results leads to the interesting question of stability. Control theory and cooperative game theory have limitations that make it hard …

Go to article

Genetic Analysis Of Ribosome Stalling And Rescue, Douglas Ray Tanner May 2009

Genetic Analysis Of Ribosome Stalling And Rescue, Douglas Ray Tanner

Theses and Dissertations

In eubacteria, ribosome stalling on broken messenger RNA transcripts can lead to cell death. The trans-translation quality control mechanism rescues many of these stalled ribosomes. In this process, tmRNA enters stalled ribosomes by mimicking a transfer RNA, accepting the stalled nascent peptide. The ribosome then releases the broken mRNA and resumes translation on a coding region within tmRNA itself. Translation of tmRNA marks the nascent peptide for destruction by the addition of a short proteolysis tag and the ribosome is released at a stop codon within the tmRNA open reading frame. An intriguing aspect of trans-translation is that …

Go to article

An Exploration Of Topologies And Communication In Large Particle Swarms, Matthew Gardner, Andrew Mcnabb, Kevin Seppi May 2009

An Exploration Of Topologies And Communication In Large Particle Swarms, Matthew Gardner, Andrew Mcnabb, Kevin Seppi

Faculty Publications

Particle Swarm Optimization (PSO) has typically been used with small swarms of about 50 particles. However, PSO is more efficiently parallelized with large swarms. We formally describe existing topologies and identify variations which are better suited to large swarms in both sequential and parallel computing environments. We examine the performance of PSO for benchmark functions with respect to swarm size and topology. We develop and demonstrate a new PSO variant which leverages the unique strengths of large swarms. “Hearsay PSO” allows for information to flow quickly through the swarm, even with very loosely connected topologies. These loosely connected topologies are …

Go to article

Lactate Threshold: The Comparison Of Running On A Land Treadmill Versus Head-Out Water Immersion Treadmill Running, Stephanie Alyce Jones May 2009

Lactate Threshold: The Comparison Of Running On A Land Treadmill Versus Head-Out Water Immersion Treadmill Running, Stephanie Alyce Jones

Theses and Dissertations

Introduction. Exercise and head-out water immersion (HOI) have consistently reported an increase in central blood volume associated with the cephalad shift in blood volume. This causes an increase in left ventricular end diastolic volume and greater stroke volume during exercise compared to exercise in air at similar metabolic costs. In contrast, the metabolic response, specifically, blood lactate accumulation during exercise combined with HOI has yielded varying results depending on the mode of exercise. At present it appears that during exercise at similar metabolic costs, cycle ergometry exercise augments plasma lactate over treadmill running while HOI reduces the plasma lactate response …

Go to article

Easemail: Easy Accessible Secure Email, Ryan B. Segeberg May 2009

Easemail: Easy Accessible Secure Email, Ryan B. Segeberg

Theses and Dissertations

Traditional email encryption methods are difficult to set up, as they require senders to obtain a message recipient's public key before a secure communication can be sent. Easy Accessible Secure Email (EASEmail) addresses the key establishment and exchange issues of encrypted email by using a lightweight symmetric key server. Users can send a secure email without establishing or exchanging keys with the recipient in advance. With usability as its primary goal, EASEmail strives to bring usable secure email communication to the masses.

Go to article

Synthesis And Evaluation Of Stimulatory Properties Of Glycolipids For Natural Killer T Cells, Xiangtian Long May 2009

Synthesis And Evaluation Of Stimulatory Properties Of Glycolipids For Natural Killer T Cells, Xiangtian Long

Theses and Dissertations

Natural killer T cells (NKT cells) are a subset of T cells. They regulate a wide range of diseases including infection, tumor growth, and autoimmune diseases, through recognizing glycolipid antigens in the context of CD1d. An understanding of the scope of glycolipid antigens would facilitate use of this cell type in controlling immune responses. Till today, a lysosomal glycolipid, isoglobotrihexosylceramide (iGb3), is the only natural glycolipid that has been found to be recognized by both human and mouse NKT cells. To elucidate the molecular basis of this specific recognition, iGb3 variants were designed and prepared: i) replacement of the C26 …

Go to article

A Pilgrimage Through English History And Culture (A-E), Gary P. Gillum, Susan Wheelwright O'Connor, Alexa Hysi May 2009

A Pilgrimage Through English History And Culture (A-E), Gary P. Gillum, Susan Wheelwright O'Connor, Alexa Hysi

Faculty Publications

An Annotated Bibliography of Books Printed in England before 1700 and housed in the L. Tom Perry Special Collections Harold B. Lee Library.

Go to article

A Pilgrimage Through English History And Culture, Gary P. Gillum, Susan Wheelwright O'Connor, Alexa Hysi May 2009

A Pilgrimage Through English History And Culture, Gary P. Gillum, Susan Wheelwright O'Connor, Alexa Hysi

Faculty Publications

An Annotated Bibliography of Books Printed in England before 1700 and housed in the L. Tom Perry Special Collections Harold B. Lee Library.

Go to article

A Pilgrimage Through English History And Culture (M-S), Gary P. Gillum, Susan Wheelwright O'Connor, Alexa Hysi May 2009

A Pilgrimage Through English History And Culture (M-S), Gary P. Gillum, Susan Wheelwright O'Connor, Alexa Hysi

Faculty Publications

An Annotated Bibliography of Books Printed in England before 1700 and housed in the L. Tom Perry Special Collections Harold B. Lee Library.

Go to article

Understanding Performance--Limiting Mechanisms In Li-Ion Batteries For High-Rate Applications, Indrajeet Vilasrao Thorat Apr 2009

Understanding Performance--Limiting Mechanisms In Li-Ion Batteries For High-Rate Applications, Indrajeet Vilasrao Thorat

Theses and Dissertations

This work presents novel modeling and experimental techniques that provide insight into liquid-phase mass transport and electron transfer processes in lithium-ion batteries. These included liquid-phase ionic mass transport (conduction and diffusion), lithium diffuion in the solid phase and electronic transport in the solid phase. Fundamental understanding of these processes is necessary to efficiently design and optimize lithium-ion batteries for different applications. To understand the effect of electrode structure on the electronic resistance of the cathode, we tested power performance of cathodes with combinations of three different carbon conductivity additives: vapor-grown carbon fibers (CF), carbon black (CB) and graphite (GR). With …

Go to article

Ionic Selectivity In L-Type Calcium Channels By Electrostatics And Hard-Core Repulsion, Dezso Boda, Douglas Henderson, Monika Valisko, Bob Eisenberg, Dirk Gillespie Apr 2009

Ionic Selectivity In L-Type Calcium Channels By Electrostatics And Hard-Core Repulsion, Dezso Boda, Douglas Henderson, Monika Valisko, Bob Eisenberg, Dirk Gillespie

Faculty Publications

A physical model of selective "ion binding" in the L-type calcium channel is constructed, and consequences of the model are compared with experimental data. This reduced model treats only ions and the carboxylate oxygens of the EEEE locus explicitly and restricts interactions to hard-core repulsion and ion–ion and ion–dielectric electrostatic forces. The structural atoms provide a flexible environment for passing cations, thus resulting in a self-organized induced-fit model of the selectivity filter. Experimental conditions involving binary mixtures of alkali and/or alkaline earth metal ions are computed using equilibrium Monte Carlo simulations in the grand canonical ensemble. The model pore rejects …

Go to article

Front Matter, Vol. 69 No. 1 Apr 2009

Front Matter, Vol. 69 No. 1

Western North American Naturalist

No abstract provided.

Go to article

Uav Intelligent Path Planning For Wilderness Search And Rescue, Rongbin Lin Apr 2009

Uav Intelligent Path Planning For Wilderness Search And Rescue, Rongbin Lin

Theses and Dissertations

In Wilderness Search and Rescue (WiSAR), the incident commander (IC) creates a probability distribution map of the likely location of the missing person. This map is important because it guides the IC in allocating search resources and coordinating efforts, but it often depends almost exclusively on prior experience and subjective judgment. We propose a Bayesian model that utilizes publicly available terrain features data to help model lost-person behaviors. This approach enables domain experts to encode uncertainty in their prior estimations and also make it possible to incorporate human-behavior data collected in the form of posterior distributions, which are used to …

Go to article

First Prev Next Last