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Articles 31 - 60 of 118
Full-Text Articles in Physical Sciences and Mathematics
An Infrastructure For Performance Measurement And Comparison Of Information Retrieval Solutions, Gary Saunders
An Infrastructure For Performance Measurement And Comparison Of Information Retrieval Solutions, Gary Saunders
Theses and Dissertations
The amount of information available on both public and private networks continues to grow at a phenomenal rate. This information is contained within a wide variety of objects, including documents, e-mail archives, medical records, manuals, pictures and music. To be of any value, this data must be easily searchable and accessible. Information Retrieval (IR) is concerned with the ability to find and gain access to relevant information. As electronic data repositories continue to proliferate, so too, grows the variety of methods used to locate and access the information contained therein. Similarly, the introduction of innovative retrieval strategies—and the optimization of …
Autonomous And Intelligent Radio Switching, Quiyi Duan
Autonomous And Intelligent Radio Switching, Quiyi Duan
Theses and Dissertations
With the proliferation of mobile applications and the abundance of wireless devices, it is increasingly common for devices to support multiple radios. When two devices are communicating they should choose the best available radio based on user preference and application requirements. This type of “radio switching” should happen automatically, so that the system optimizes performance dynamically. To achieve this objective, we design an Autonomous and Intelligent Radio Switching (AIRS) system to leverage the radio heterogeneity common in today's wireless devices. The AIRS system consists of three key components. First, we design a radio preference evaluation module to dynamically select the …
Generalized Random Walks, Their Trees, And The Transformation Method Of Option Pricing, Thomas Gordon Stewart
Generalized Random Walks, Their Trees, And The Transformation Method Of Option Pricing, Thomas Gordon Stewart
Theses and Dissertations
The random walk is a powerful model. Chemistry, Physics, and Finance are just a few of the disciplines that model with the random walk. It is clear from its varied uses that despite its simplicity, the simple random walk it very flexible. There is one major drawback, however, to the simple random walk and the geometric random walk. The limiting distribution is either normal, lognormal, or a levy process with infinite variance. This thesis introduces an new random walk aimed at overcoming this drawback. Because the simple random walk and the geometric random walk are special cases of the proposed …
I. Thermodynamics And Magnetism Of Cu2ocl2 Ii. Repairs To Microcalorimeter The "2"S Are Subscripts, And The Second 2 Is Preceded By A Lower Case L, Not A One, Thomas J. Parry
Theses and Dissertations
Adiabatic calorimetry provides accurate and precise specific heat (Cp) data. From this data, thermodynamic functions may be calculated. Cu2OCl2, melanothallite, became of interest as part of a study of a particular thermochemical cycle. The experimental specific heat data and the calculated thermodynamic functions are reported here. Free energies of formation, calculated from the thermodynamic functions, suggest the particular cycle of interest with this compound as an intermediate is not feasible; uncertainty as to the accuracy of CuO and CuCl2 data used in the calculations indicate further study may be necessary. Upon collection of the specific heat data, an antiferromagnetic transition …
A Radical Conjugate Addition Approach To The Total Synthesis Of Celogentin C, Steven G. Capps
A Radical Conjugate Addition Approach To The Total Synthesis Of Celogentin C, Steven G. Capps
Theses and Dissertations
The synthesis of five chiral DBFOX (dibenzofuran-oxazoline) ligands with either aryl or benzyl substituents will be presented. The requisite amino alcohols were obtained with high enantioselectivity either commercially (DBFOX/Bn), via Sharpless asymmetric aminohydroxylation (DBFOX/Nap, DBFOX/t-BuPh, DBFOX/Pip), or via phase-transfer catalyzed asymmetric alkylation (DBFOX/MeNap). These ligands, complexed with Mg(NTf2)2, were used as Lewis acid promoters of enantioselective radical conjugate additions to α/β-unsaturated nitro-amides/esters. A summary of these results is presented and discussed. These findings led us to believe that our initial binding model between metal, ligand, and substrate was flawed. Thus, we figured that if we started with a functionality known …
A Microanalytical Approach To Understanding The Origin Of Cumulate Xenoliths From Mauna Kea, Hawaii, Megan Pickard
A Microanalytical Approach To Understanding The Origin Of Cumulate Xenoliths From Mauna Kea, Hawaii, Megan Pickard
Theses and Dissertations
Cumulate xenoliths erupted with alkalic hawaiite lavas from a postshield cinder cone on Mauna Kea, Hawaii include a variety of mafic and ultramafic rock types. Previous studies of major and trace element compositions of minerals in the xenoliths are interpreted to show transitional to alkalic magma parentages from the postshield stage, although any orthopyroxene-bearing xenoliths are considered to have tholeiitic parents. Major element compositions minerals were analyzed using the electron microprobe and trace element compositions of clinopyroxene grains were analyzed by laser ablation inductively coupled plasma mass spectrometry. In this study, major element compositions of clinopyroxene, olivine and plagioclase grains …
On Autonomous Multi-Agent Control In Wilderness Search And Rescue: A Mixed Initiative Approach, Benjamin C. Hardin
On Autonomous Multi-Agent Control In Wilderness Search And Rescue: A Mixed Initiative Approach, Benjamin C. Hardin
Theses and Dissertations
Searching for lost people in a Wilderness Search and Rescue (WiSAR) scenario is a task that can benefit from large numbers of agents, some of whom may be robotic. These agents may have differing levels of autonomy, determined by the set of tasks they are performing. In addition, the level of autonomy that results in the best performance may change due to varying workload or other factors. Allowing a supervisor and a searcher to jointly decide the correct level of autonomy for a given situation (“mixed initiative”) results in better overall performance than giving an agent absolute control over their …
Magmatic Sulfur And Chlorine Abundances At Stromboli, Italy And Their Role In The Formation Of Vesicle-Hosted Metal Alloys, Nichelle Lynn Baxter
Magmatic Sulfur And Chlorine Abundances At Stromboli, Italy And Their Role In The Formation Of Vesicle-Hosted Metal Alloys, Nichelle Lynn Baxter
Theses and Dissertations
Strand et al. (2002) discovered small metal alloy grains rich in Cu, Co, and Sn (maximum size 150 µm) in vesicles of lava from Kilauea Volcano. These alloys are also found in basaltic rocks of several Italian volcanoes. To better understand the origin of these metal-rich grains, bombs from Stromboli Volcano were examined. Two bomb types were collected from Stromboli: pumiceous bombs and scoriaceous bombs. Bulk rock trace element geochemistry indicates that there are no significant differences in Cu, Co, or Sn (the three major components of the metal alloys) between the pumiceous and scoriaceous bombs. Comparison of olivine melt …
Regulators Of G-Protein Signaling, Rgs13 And Rgs16, Are Associated With Cxcl12-Mediated Cd4+ T Cell Migration, Lijin Xia
Theses and Dissertations
Chemokines are important chemical signals that guide lymphocyte movement within the immune system and promote the organization and functions of germinal centers (GCs) in the secondary lymphoid tissues. Previous studies have shown that GC T cells exhibit high expression of chemokine receptor 4, CXCR4, but that these cells are unable to migrate to the ligand for this receptor, the chemokine CXCL12. This “migratory paralysis” to CXCL12 was found to be correlated with the expression of two Regulators of G-protein Signaling, RGS13 and RGS16 in the GC T cells. The objective of my research was to determine whether RGS13 and RGS16 …
Pre-Eruptive Conditions Of The Oligocene Wah Wah Springs Tuff, Southeastern Great Basin Ignimbrite Province, Kurtus Steven Woolf
Pre-Eruptive Conditions Of The Oligocene Wah Wah Springs Tuff, Southeastern Great Basin Ignimbrite Province, Kurtus Steven Woolf
Theses and Dissertations
The Wah Wah Springs Tuff (30.0 Ma) is one of several very large volume ash-flow tuffs (>3200 km³ of erupted magma) that were emplaced near the peak of the flare-up of activity in the Great Basin ignimbrite province of western North America. It can be characterized as a "monotonous intermediate" ignimbrite because of its intermediate concentrations of silica (~63 to ~70 wt. %), apparent uniform chemical and mineralogical characteristics, and crystal-rich nature (32 ± 10 % phenocrysts on a dense rock basis). The major phase assemblage found throughout deposit is similar to other monotonous intermediates with a few exceptions …
Watertight Trimmed Nurbs, Thomas W. Sederberg, Xin Li, Hongwei Lin, Heather Ipson
Watertight Trimmed Nurbs, Thomas W. Sederberg, Xin Li, Hongwei Lin, Heather Ipson
Faculty Publications
This paper addresses the long-standing problem of the unavoidable gaps that arise when expressing the intersection of two NURBS surfaces using conventional trimmed-NURBS representation. The solution converts each trimmed NURBS into an untrimmed T-Spline, and then merges the untrimmed T-Splines into a single, watertight model. The solution enables watertight fillets of NURBS models, as well as arbitrary feature curves that do not have to follow isoparameter curves. The resulting T-Spline representation can be exported without error as a collection of NURBS surfaces.
Spectroscopic Study Of Compressible Mobile Phase And Stationary Phase Behavior In Chromatography, Lawrence R. Baker
Spectroscopic Study Of Compressible Mobile Phase And Stationary Phase Behavior In Chromatography, Lawrence R. Baker
Theses and Dissertations
Raman spectroscopy, laser-induced fluorescence, and sum-frequency generation (SFG) spectroscopy are used to investigate the behavior of compressible mobile phases and stationary phases under a variety of chromatographic conditions. Efforts to understand and optimize separations employing compressible mobile phases have been limited by a lack of understanding of the mobile phase density gradient. Mobile phase compressibility leads to gradients in linear velocity and solute retention and affects separation speed and efficiency, especially in packed columns. This work describes on-column density measurement of CO2, a common carrier fluid for SFC and SGC, in packed capillary columns using Raman microspectroscopy. On-column detection by …
Assessing Multivariate Heritability Through Nonparametric Methods, Benjamin Alan Carper
Assessing Multivariate Heritability Through Nonparametric Methods, Benjamin Alan Carper
Theses and Dissertations
The similarities between generations of living subjects are often quantified by heritability. By distinguishing genotypic variation, or variation due to parental pairings, from phenotypic variation, or normal intraspecies variation, the heritability of traits can be estimated. Due to the multivariate nature of many traits, such as size and shape, computation of heritability can be difficult. Also, assessment of the variation of the heritability estimate is extremely difficult. This study uses nonparametric methods, namely the randomization test and the bootstrap, to obtain both a measure of the extremity of the observed heritability and an assessment of the uncertainty.
Theory And Estimation Of Acoustic Intensity And Energy Density, Derek C. Thomas
Theory And Estimation Of Acoustic Intensity And Energy Density, Derek C. Thomas
Theses and Dissertations
In order to facilitate the acquisition and accurate interpretation of intensity and energy density data in high-amplitude pressure fields, the expressions for intensity and energy density are examined to ascertain the impact of nonlinear processes on the standard expressions. Measurement techniques for estimating acoustic particle velocity are presented. The finite-difference method is developed in an alternate manner and presented along with bias and confidence estimates. Additionally, two new methods for estimating the local particle velocity are presented. These methods appears to eliminate the errors and bias associated with the finite-difference technique for certain cases.
Lyapunov Exponents And Invariant Manifold For Random Dynamical Systems In A Banach Space, Zeng Lian
Lyapunov Exponents And Invariant Manifold For Random Dynamical Systems In A Banach Space, Zeng Lian
Theses and Dissertations
We study the Lyapunov exponents and their associated invariant subspaces for infinite dimensional random dynamical systems in a Banach space, which are generated by, for example, stochastic or random partial differential equations. We prove a multiplicative ergodic theorem. Then, we use this theorem to establish the stable and unstable manifold theorem for nonuniformly hyperbolic random invariant sets.
Simple, Secure, Selective Delegation In Online Identify Systems, Bryant Gordon Cutler
Simple, Secure, Selective Delegation In Online Identify Systems, Bryant Gordon Cutler
Theses and Dissertations
The ability to delegate privileges to others is so important to users of online identity systems that users create ad hoc delegation systems by sharing authentication credentials if no other easy delegation mechanism is available. With the rise of internet-scale relationship-based single sign-on protocols like OpenID, the security risks of password sharing are unacceptable. We therefore propose SimpleAuth, a simple modification to relationship-based authentication protocols that gives users a secure way to selectively delegate subsets of their privileges, making identity systems more flexible and increasing user security. We also present a proof-of-concept implementation of the SimpleAuth pattern using the sSRP …
Predicting The Longevity Of Dvdr Media By Periodic Analysis Of Parity, Jitter, And Ecc Performance Parameters, Daniel Patrick Wells
Predicting The Longevity Of Dvdr Media By Periodic Analysis Of Parity, Jitter, And Ecc Performance Parameters, Daniel Patrick Wells
Theses and Dissertations
For the last ten years, DVD-R media have played an important role in the storage of large amounts of digital data throughout the world. During this time it was assumed that the DVD-R was as long-lasting and stable as its predecessor, the CD-R. Several reports have surfaced over the last few years questioning the DVD-R's ability to maintain many of its claims regarding archival quality life spans. These reports have shown a wide range of longevity between the different brands. While some DVD-Rs may last a while, others may result in an early and unexpected failure. Compounding this problem is …
The Tropical Jacobian Of A Tropical Elliptic Curve Is S^1(Q), Darryl Gene Wade
The Tropical Jacobian Of A Tropical Elliptic Curve Is S^1(Q), Darryl Gene Wade
Theses and Dissertations
We establish consistent definitions for divisors, principal divisors, and Jacobians of a tropical elliptic curve and show that for a tropical elliptic cubic C , the associated Jacobian (or zero divisor class group) is the group S^1(Q).
An Ultrahigh Stability, Low-Noise Laser Current Driver With Digital Control, Christopher J. Erickson, Marshall Van Zijll, Greg Doermann, Dallin S. Durfee
An Ultrahigh Stability, Low-Noise Laser Current Driver With Digital Control, Christopher J. Erickson, Marshall Van Zijll, Greg Doermann, Dallin S. Durfee
Faculty Publications
We present a low-noise, high modulation-bandwidth design for a laser current driver with excellent long-term stability. The driver improves upon the commonly used Hall–Libbrecht design. The current driver can be operated remotely by way of a microprocessing unit, which controls the current set point digitally. This allows precise repeatability and improved accuracy and stability. It also allows the driver to be placed near the laser for reduced noise and for lower phase lag when using the modulation input. We present the theory of operation for our driver in detail, and give a thorough characterization of its stability, noise, set-point accuracy …
Complete Tropical Bezout's Theorem And Intersection Theory In The Tropical Projective Plane, Gretchen Rimmasch
Complete Tropical Bezout's Theorem And Intersection Theory In The Tropical Projective Plane, Gretchen Rimmasch
Theses and Dissertations
In this dissertation we prove a version of the tropical Bezout's theorem which is applicable to all tropical projective plane curves. There is a version of tropical Bezout's theorem presented in other works which applies in special cases, but we provide a proof of the theorem for all tropical projective plane curves. We provide several different definitions of intersection multiplicity and show that they all agree. Finally, we will use a tropical resultant to determine the intersection multiplicity of points of intersection at infinite distance. Using these new definitions of intersection multiplicity we prove the complete tropical Bezout's theorem.
Using Live Sequence Chart Specifications For Formal Verification, Rahul Kumar
Using Live Sequence Chart Specifications For Formal Verification, Rahul Kumar
Theses and Dissertations
Formal methods play an important part in the development as well as testing stages of software and hardware systems. A significant and often overlooked part of the process is the development of specifications and correctness requirements for the system under test. Traditionally, English has been used as the specification language, which has resulted in verbose and difficult to use specification documents that are usually abandoned during product development. This research focuses on investigating the use of Live Sequence Charts (LSCs), a graphical and intuitive language directly suited for expressing communication behaviors of a system as the specification language for a …
Genetic Analysis Of The Role Of Smpb In Establishing The Reading Frame On Tmrna, Talina Christensen Watts
Genetic Analysis Of The Role Of Smpb In Establishing The Reading Frame On Tmrna, Talina Christensen Watts
Theses and Dissertations
Ribosomes translate the genetic information encoded by mRNA into proteins. Defective mRNAs can cause stalling of translating ribosomes. The molecule tmRNA (transfer-messenger RNA) rescues stalled ribosomes in eubacteria. Together with its protein partner SmpB, tmRNA mimics a tRNA by entering the ribosomal A site and linking an alanine residue to the growing polypeptide chain. The ribosome then abandons the defective mRNA template and resumes translation on tmRNA, adding ten more amino acids to the nascent polypeptide. As a result of tmRNA action, stalled ribosomes are released and recycled, the defective mRNA is destroyed, and the aborted protein product is tagged …
Ion Permeation Through Membrane Channels: Molecular Dynamics Simulations Studies, Morad Mustafa
Ion Permeation Through Membrane Channels: Molecular Dynamics Simulations Studies, Morad Mustafa
Theses and Dissertations
Molecular dynamics simulation was used to study ion permeation through different membrane proteins embedded in a lipid bilayer (DMPC) with different saline solutions. The potential of mean force (PMF) for ion transport was obtained by umbrella sampling simulations. A revised MacKerell force field for tryptophan residues was studied using gramicidin A (gA) channel as a test model. The revised force field contribution to the Na+ PMF was consonant with the prediction from the experimental results, but in stark contrast to the prediction of the CHARMM force field, version 22, for the tryptophan side-chain. A new grid-based correction map algorithm by …
Early Dynamics Of Ultracold Neutral Plasmas, Adam W. Denning
Early Dynamics Of Ultracold Neutral Plasmas, Adam W. Denning
Theses and Dissertations
We report new studies on the early-time dynamics of ultracold neutral plasmas. We use fluorescence spectroscopy to probe plasma dynamics on the nanosecond time scale. We determine the rms ion velocity during the initial plasma period. The initial ion acceleration is found as the time derivative of the ion velocity. We compare to a theoretical model. The experimental results agree with the model at low plasma densities. However, the ion acceleration is a factor of ten lower than the model at higher densities. The cause of this discrepancy is currently unknown.
Adapting Adtrees For Improved Performance On Large Datasets With High Arity Features, Robert D. Van Dam
Adapting Adtrees For Improved Performance On Large Datasets With High Arity Features, Robert D. Van Dam
Theses and Dissertations
The ADtree, a data structure useful for caching sufficient statistics, has been successfully adapted to grow lazily when memory is limited and to update sequentially with an incrementally updated dataset. However, even these modified forms of the ADtree still exhibit inefficiencies in terms of both space usage and query time, particularly on datasets with very high dimensionality and with high arity features. We propose five modifications to the ADtree, each of which can be used to improve size and query time under specific types of datasets and features. These modifications also provide an increased ability to precisely control how an …
Rational Schur Rings Over Abelian Groups, Brent L. Kerby
Rational Schur Rings Over Abelian Groups, Brent L. Kerby
Theses and Dissertations
In 1993, Muzychuk showed that the rational S-rings over a cyclic group Z_n are in one-to-one correspondence with sublattices of the divisor lattice of n, or equivalently, with sublattices of the lattice of subgroups of Z_n. This idea is easily extended to show that for any finite group G, sublattices of the lattice of characteristic subgroups of G give rise to rational S-rings over G in a natural way. Our main result is that any finite group may be represented as the automorphism group of such a rational S-ring over an abelian p-group. In order to show this, we first …
Homomorphisms Into The Fundamental Group Of One-Dimensional And Planar Peano Continua, Curtis Andrew Kent
Homomorphisms Into The Fundamental Group Of One-Dimensional And Planar Peano Continua, Curtis Andrew Kent
Theses and Dissertations
Let X be a planar or one-dimensional Peano continuum. Let E be a Hawaiian Earring with fundamental group H. We show that every homomorphism from H to the fundamental group of X is conjugate to a homomorphism which is induced by a continuous function.
Arbitrary Degree T-Splines, Gordon Thomas Finnigan
Arbitrary Degree T-Splines, Gordon Thomas Finnigan
Theses and Dissertations
T-Splines is a freeform surface type similar to NURBS, that allows partial rows of control points. Up until now, T-Splines have only been formally defined for the degree three case. This paper extends the definition to support all odd, even, and mixed degree T-Spline surfaces, making T-Splines a proper superset of all standard NURBS surfaces.
Ordinal Regression To Evaluate Student Ratings Data, Emily Brooke Bell
Ordinal Regression To Evaluate Student Ratings Data, Emily Brooke Bell
Theses and Dissertations
Student evaluations are the most common and often the only method used to evaluate teachers. In these evaluations, which typically occur at the end of every term, students rate their instructors on criteria accepted as constituting exceptional instruction in addition to an overall assessment. This presentation explores factors that influence student evaluations using the teacher ratings data of Brigham Young University from Fall 2001 to Fall 2006. This project uses ordinal regression to model the probability of an instructor receiving a good, average, or poor rating. Student grade, instructor status, class level, student gender, total enrollment, term, GE class status, …
A Review Of Fibroblast Populated Collagen Lattices, J. C. Dallon, Paul H. Ehrlich
A Review Of Fibroblast Populated Collagen Lattices, J. C. Dallon, Paul H. Ehrlich
Faculty Publications
Bellaes introduction of the fibroblast populated collagen lattice (FPCL) (1) has facilitated the study of collagen-cell interactions. As a result of the numerous modifications of the casting of FPCL's, the in vivo applications of these in vitro findings has been confusing. Here experimental FPCL contraction findings are viewed in regard to three proposed mechanisms responsible for lattice contraction. The cellular mechanisms responsible for generating FPCL contraction are: cell contraction, cell tractional forces related to cell locomotion, and initial cell elongation and spreading.