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Faculty Publications

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Articles 2731 - 2760 of 3786

Full-Text Articles in Physical Sciences and Mathematics

Isobaric Analog States Of Neutron-Rich Nuclei. Doppler Shift As A Measurement Tool For Resonance Excitation Functions, P. Boutachkov, G. V. Rogachev, V. Z. Goldberg, A. Aprahamian, F. D. Becchetti, J. P. Bychowski, Y. Chen, G. Chubarian, P. A. Deyoung, J. J. Kolata, L. O. Lamm, Graham F. Peaslee, M. Quinn, B. B. Skorodumov, A. Wohr Apr 2005

Isobaric Analog States Of Neutron-Rich Nuclei. Doppler Shift As A Measurement Tool For Resonance Excitation Functions, P. Boutachkov, G. V. Rogachev, V. Z. Goldberg, A. Aprahamian, F. D. Becchetti, J. P. Bychowski, Y. Chen, G. Chubarian, P. A. Deyoung, J. J. Kolata, L. O. Lamm, Graham F. Peaslee, M. Quinn, B. B. Skorodumov, A. Wohr

Faculty Publications

We present a new approach for the measurement of resonance excitation functions of neutron-rich nuclei using Doppler shift information. Preliminary data from the first application of the method is presented in the spectroscopy studies of 7He isobaric analog states in 7Li.

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Two-Photon Photoionization Of The Ca 4s3d^1d2 Level In An Optical Dipole Trap, E. A. Cummings, J. E. Daily, Dallin S. Durfee, Scott D. Bergeson, R. Gommers Apr 2005

Two-Photon Photoionization Of The Ca 4s3d^1d2 Level In An Optical Dipole Trap, E. A. Cummings, J. E. Daily, Dallin S. Durfee, Scott D. Bergeson, R. Gommers

Faculty Publications

We report an optical dipole trap for calcium. The trap is created by focusing a 488-nm argon-ion laser beam into a calcium magneto-optical trap. The argon-ion laser photoionizes atoms in the trap because of a near-resonance with the 4s4f 1^F3 level. By measuring the dipole-trap decay rate as a function of argon-ion laser intensity, we determine the 1^F3 photoionization cross section at our wavelength to be approximately 230 Mb.

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Long-Lived Spin Coherence States In Semiconductor Heterostructures, Yuriy V. Pershin Dr Apr 2005

Long-Lived Spin Coherence States In Semiconductor Heterostructures, Yuriy V. Pershin Dr

Faculty Publications

We study evolution of electron spin coherence having nonhomogeneous direction of spin polarization vector in semiconductor heterostructures. It is found that the electron spin relaxation time due to the D’yakonov- Perel’ relaxation mechanism essentially depends on the initial spin polarization distribution. This effect has its origin in the coherent spin precession of electrons diffusing in the same direction. We predict a long spin relaxation time of a novel structure: a spin coherence standing wave and discuss its experimental realization.

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Tb3+-Doped K Pb2Br5: Low-Energy Phonon Mid-Infrared Laser Crystal, U. N. Roy, R. H. Hawrami, Y. Cui, S. Morgan, A. Burger, K. C. Mandal, C. C. Noblitt, S. A. Speakman, K. Rademaker, S. A. Payne Apr 2005

Tb3+-Doped K Pb2Br5: Low-Energy Phonon Mid-Infrared Laser Crystal, U. N. Roy, R. H. Hawrami, Y. Cui, S. Morgan, A. Burger, K. C. Mandal, C. C. Noblitt, S. A. Speakman, K. Rademaker, S. A. Payne

Faculty Publications

No abstract provided.

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Prioritized Multiplicative Schwarz Procedures For Solving Linear Systems, Nathaniel Powell, Kevin Seppi, Quinn O. Snell, David Wingate Apr 2005

Prioritized Multiplicative Schwarz Procedures For Solving Linear Systems, Nathaniel Powell, Kevin Seppi, Quinn O. Snell, David Wingate

Faculty Publications

We describe a new algorithm designed to quickly and robustly solve general linear problems of the form Ax = b. We describe both serial and parallel versions of the algorithm, which can be considered a prioritized version of an Alternating Multiplicative Schwarz procedure. We also adopt a general view of alternating Multiplicative Schwarz procedures which motivates their use on arbitrary problems (even which may not have arisen from problems that are naturally decomposable) by demonstrating that, even in a serial context, algorithms should use many, many partitions to accelerate convergence; having such an over-partitioned system also allows easy parallelization of …

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Sound-Quality Analysis Of Sewing Machines (A), James Chatterley, Andrew Boone, Jonathan T. Blotter, Scott D. Sommerfeldt Apr 2005

Sound-Quality Analysis Of Sewing Machines (A), James Chatterley, Andrew Boone, Jonathan T. Blotter, Scott D. Sommerfeldt

Faculty Publications

Sound quality analysis procedure and results for six sewing machines ranging from entry level to professional grade will be presented. The procedure consisted of jury-based listening tests and quantification of sound quality using standard metrics. The procedures and analysis of the jury testing will be presented and discussed. The correlation between the quantitative metrics and the qualitative jury results will be presented. Sound localization scans, using near field acoustic holography techniques with accompanying results, performed in order to determine machine sound hot spots and possible sources for undesired sounds, will also be presented. Proposed modifications to machine structure in order …

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Semiclassical Nonadiabatic Dynamics With Quantum Trajectories, Vitaly A. Rassolov, Sophya V. Garashchuk Mar 2005

Semiclassical Nonadiabatic Dynamics With Quantum Trajectories, Vitaly A. Rassolov, Sophya V. Garashchuk

Faculty Publications

Dynamics based on quantum trajectories with approximate quantum potential is generalized to nonadiabatic systems and its semiclassical properties are discussed. The formulation uses the mixed polar-coordinate space representation of a wave function. The polar part describes the overall time evolution of the wave-function components semiclassically using the single-surface approximate quantum potential. The coordinate part represents a complex“population” amplitude, which in case of localized coupling can be solved for quantum mechanically in an efficient manner. In the high-energy regime this is accomplished by using a small basis determined by the coupling between surfaces. An illustration is given for a typical curve-crossing …

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Study Of The Pion Trajectory In The Photoproduction Of Leading Neutrons At Hera, S. Chekanov, M. Derrick, D. Krakauer, J. H. Loizides, S. Magill, S. Miglioranzi, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, G. Sartorelli Mar 2005

Study Of The Pion Trajectory In The Photoproduction Of Leading Neutrons At Hera, S. Chekanov, M. Derrick, D. Krakauer, J. H. Loizides, S. Magill, S. Miglioranzi, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, G. Sartorelli

Faculty Publications

Energetic neutrons produced in ep collisions at HERA have been studied with the ZEUS detector in the photoproduction regime at a mean photon-proton center-of-mass energy of 220 GeV. The neutrons carry a large fraction 0.64

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Orbital Dependence Of The Fermi Liquid State In Sr2ruo4, T. E. Kidd, T. Valla, A. V. Fedorov, P. D. Johnson, R. J. Cava, M. K. Haas Mar 2005

Orbital Dependence Of The Fermi Liquid State In Sr2ruo4, T. E. Kidd, T. Valla, A. V. Fedorov, P. D. Johnson, R. J. Cava, M. K. Haas

Faculty Publications

We have used angle-resolved photoemission spectroscopy to determine the bulk electronic structure of Sr2RuO4 above and below the Fermi liquid crossover near 25 K. Our measurements indicate that the properties of the system are highly orbital dependent. The quasi-2D gamma band displays Fermi liquid behavior while the remaining low energy bands show exotic properties consistent with quasi-1D behavior. In the Fermi liquid state below 25 K, the gamma band dominates the electronic properties, while at higher temperatures the quasi-1D ß and α bands become more important.

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Temperature Dependence Of The Double Layer Capacitance For The Restricted Primitive Model Of An Electrolyte Solution From A Density Functional Approach, Douglas Henderson, J. Reszko-Zygmunt, Stefan Sokolowski, Dezso Boda Feb 2005

Temperature Dependence Of The Double Layer Capacitance For The Restricted Primitive Model Of An Electrolyte Solution From A Density Functional Approach, Douglas Henderson, J. Reszko-Zygmunt, Stefan Sokolowski, Dezso Boda

Faculty Publications

We apply a different version of the density functional theory, given by Pizio, Patrykiejew, and Sokolowski [J. Chem. Phys. 121, 11957 (2004)], for a nonuniform restricted primitive model of an electrolyte solution to evaluate the temperature dependence of the capacitance of an electric double layer. We show that this theory is capable of reproducing the computer simulation data at a quantitative level. In particular, the reversal of the temperature dependence of the capacitance at low temperatures is predicted. This phenomenon has been difficult to predict from theory. Further, this theory also leads to an accurate description of the double layer …

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A New Blind Method For Detecting Novel Steganography, Brent T. Mcbride, Gilbert L. Peterson, Steven C. Gustafson Feb 2005

A New Blind Method For Detecting Novel Steganography, Brent T. Mcbride, Gilbert L. Peterson, Steven C. Gustafson

Faculty Publications

Steganography is the art of hiding a message in plain sight. Modern steganographic tools that conceal data in innocuous-looking digital image files are widely available. The use of such tools by terrorists, hostile states, criminal organizations, etc., to camouflage the planning and coordination of their illicit activities poses a serious challenge. Most steganography detection tools rely on signatures that describe particular steganography programs. Signature-based classifiers offer strong detection capabilities against known threats, but they suffer from an inability to detect previously unseen forms of steganography. Novel steganography detection requires an anomaly-based classifier. This paper describes and demonstrates a blind classification …

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Graphs Whose Minimal Rank Is Two: The Finite Fields Case, Wayne Barrett, Hein Van Der Holst, Raphael Loewy Feb 2005

Graphs Whose Minimal Rank Is Two: The Finite Fields Case, Wayne Barrett, Hein Van Der Holst, Raphael Loewy

Faculty Publications

Let F be a finite field, G = (V,E) be an undirected graph on n vertices, and let S(F,G) be the set of all symmetric n × n matrices over F whose nonzero off-diagonal entries occur in exactly the positions corresponding to the edges of G. Let mr(F,G) be the minimum rank of all matrices in S(F,G). If F is a finite field with p^t elements, p does not = 2, it is shown that mr(F,G) ≤ 2 if and only if the complement of G is the join of a complete graph with either the union of at most …

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Fast And Robust Incremental Action Prediction For Interactive Agents, Jonathan Dinerstein, Parris K. Egbert, Dan A. Ventura Feb 2005

Fast And Robust Incremental Action Prediction For Interactive Agents, Jonathan Dinerstein, Parris K. Egbert, Dan A. Ventura

Faculty Publications

The ability for a given agent to adapt on-line to better interact with another agent is a difficult and important problem. This problem becomes even more difficult when the agent to interact with is a human, since humans learn quickly and behave non-deterministically. In this paper we present a novel method whereby an agent can incrementally learn to predict the actions of another agent (even a human), and thereby can learn to better interact with that agent. We take a case-based approach, where the behavior of the other agent is learned in the form of state-action pairs. We generalize these …

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Ikum: An Integrated Web Personalization Platform Based On Content Structures And User Behavior, Magdalini Eirinaki, Joannis Vlachakis, Sarabjot Anand Jan 2005

Ikum: An Integrated Web Personalization Platform Based On Content Structures And User Behavior, Magdalini Eirinaki, Joannis Vlachakis, Sarabjot Anand

Faculty Publications

Web personalization is the process of customizing a web site to the needs of each specific user or set of users, taking advantage of the knowledge acquired through the analysis of the user’s navigational behavior. The objective of the I-KnowUMine project (IKUM) is to develop an integrated platform (referred to in the paper as the “IKUM system”) that uses state of the art technology and research results from different application domains in order to provide the basis for the development of online services in a wide range of application areas, presenting personalized content, services and applications to users in a …

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Mass-To-Light Ratio Gradients In Early-Type Galaxy Haloes, N. R. Napolitano, M. Capaccioli, Aaron J. Romanowsky, N. G. Douglas, M. R. Merrifield, K. Kuijken, M. Arnaboldi, O. Gerhard, K. C. Freeman Jan 2005

Mass-To-Light Ratio Gradients In Early-Type Galaxy Haloes, N. R. Napolitano, M. Capaccioli, Aaron J. Romanowsky, N. G. Douglas, M. R. Merrifield, K. Kuijken, M. Arnaboldi, O. Gerhard, K. C. Freeman

Faculty Publications

Owing to the fact that the near future should see a rapidly expanding set of probes of the halo masses of individual early-type galaxies, we introduce a convenient parameter for characterizing the halo masses from both observational and theoretical results: ∇ℓϒ, the logarithmic radial gradient of the mass-to-light ratio. Using halo density profiles from Λ-cold dark matter (CDM) simulations, we derive predictions for this gradient for various galaxy luminosities and star formation efficiencies εSF. As a pilot study, we assemble the available ∇ℓϒ data from kinematics in early-type galaxies – representing the first unbiased study of halo masses in a …

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Differential Tethering Of Log Phase Trypanosoma Brucei Onto Chemically Distinct Surfaces, Darrell R. Fry, Lydia Archuleta, Ashley Dunham, Justin Rains Jan 2005

Differential Tethering Of Log Phase Trypanosoma Brucei Onto Chemically Distinct Surfaces, Darrell R. Fry, Lydia Archuleta, Ashley Dunham, Justin Rains

Faculty Publications

Our long-term objective is to understand and model the motility of T. brucei. Obtaining high quality images of T. brucei that allow one to differentiate between cell body movement and flagallar movement is difficult with T. brucei because the flagellum is attached along the cell body. Currently, our approach his to tether T. brucei onto a microscope friendly surface. The contributions to the ISIS our progress to date. Specifically, we look at the adhesion density of T. brucei to numerous microscope friendly surfaces and at the optimum adhesion conditions for T. brucei.

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Data Management And Visualization Of X-Ray Diffraction Spectra From Thin Film Ternary Composition Spreads, I. Takeuchi, C. J. Long, O. O. Famodu, M. Murakami, Jason R. Hattrick-Simpers, G. W. Rubloff, M. Stukowski, K. Rajan Jan 2005

Data Management And Visualization Of X-Ray Diffraction Spectra From Thin Film Ternary Composition Spreads, I. Takeuchi, C. J. Long, O. O. Famodu, M. Murakami, Jason R. Hattrick-Simpers, G. W. Rubloff, M. Stukowski, K. Rajan

Faculty Publications

We discuss techniques for managing and visualizing x-ray diffraction spectrum data for thin film composition spreads which map large fractions of ternary compositional phase diagrams. An in-house x-ray microdiffractometer is used to obtain spectra from over 500 different compositions on an individual spread. The MATLAB software is used to quickly organize the data and create various plots from which one can quickly grasp different information regarding structural and phase changes across the composition spreads. Such exercises are valuable in rapidly assessing the “overall” picture of the structural evolution across phase diagrams before focusing in on specific composition regions for detailed …

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Interphase Exchange Coupling In Fe/Sm-Co Bilayers With Gradient Fe Thickness, Ming-Hui Yu, Jason R. Hattrick-Simpers, Ichiro Takeuchi, Jing Li, Z. L. Wang, J. P. Liu, S. E. Lofland, Somdev Tyagi, J. W. Freeland, D. Giubertoni, M. Bersani, M. Anderle Jan 2005

Interphase Exchange Coupling In Fe/Sm-Co Bilayers With Gradient Fe Thickness, Ming-Hui Yu, Jason R. Hattrick-Simpers, Ichiro Takeuchi, Jing Li, Z. L. Wang, J. P. Liu, S. E. Lofland, Somdev Tyagi, J. W. Freeland, D. Giubertoni, M. Bersani, M. Anderle

Faculty Publications

We have fabricated Fe∕Sm–Co bilayers with gradient Fe thicknesses in order to systematically study the dependence of exchange coupling on the thickness of the Fe layer. The Fe layer was deposited at two different temperatures (150 and 300°C) to study the effect of deposition temperature on the exchange coupling. Magneto-optical Kerr effect and x-ray magnetic circular dichroism (XMCD) have been employed as nondestructive rapid characterization tools to map the magnetic properties of the gradient samples. Systematic enhancement in exchange coupling between the soft layer and the hard layer is observed as the soft layer thickness is decreased. Separate exchange couplings …

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Monsoon-Driven Biogeochemical Processes In The Arabian Sea, Jerry D. Wiggert, Raleigh Hood, Karl Banse, John Kindle Jan 2005

Monsoon-Driven Biogeochemical Processes In The Arabian Sea, Jerry D. Wiggert, Raleigh Hood, Karl Banse, John Kindle

Faculty Publications

Although it is nominally a tropical locale, the semiannual wind reversals associated with the Monsoon system of the Arabian Sea result annually in two distinct periods of elevated biological activity. While in both cases monsoonal forcing drives surface layer nutrient enrichment that supports increased rates of primary productivity, fundamentally different entrainment mechanisms are operating in summer (Southwest) and winter (Northeast) Monsoons. Moreover, the intervening intermonsoon periods, during which the region relaxes toward oligotrophic conditions more typical of tropical environments, provide a stark contrast to the dynamic biogeochemical activity of the monsoons. The resulting spatial and temporal variability is great and …

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Novel Cyanine-Amp Conjugates For Efficient 5' Rna Fluorescent Labeling By One-Step Transcription And Replacement Of [γ-32P] Atp In Rna Structural Investigation, Na Li, Changjun Yu, Faqing Huang Jan 2005

Novel Cyanine-Amp Conjugates For Efficient 5' Rna Fluorescent Labeling By One-Step Transcription And Replacement Of [γ-32P] Atp In Rna Structural Investigation, Na Li, Changjun Yu, Faqing Huang

Faculty Publications

Two novel fluorescent cyanine-AMP conjugates, F550/570 and F650/670, have been synthesized to serve as transcription initiators under the T7 φ2.5 promoter. Efficient fluorophore labeling of 5′ RNA is achieved in a single transcription step by including F550/570 and F650/670 in the transcription solution. The current work makes fluorescently labeled RNA readily available for broad applications in biochemistry, molecular biology, structural biology and biomedicine. In particular, site-specifically fluorophore-labeled large RNAs prepared by the current method may be used to investigate RNA structure, folding and mechanism by various fluorescence techniques. In addition, F550/570 and F650/670 may replace [γ-32P]ATP to prepare …

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Thorium-Based Thin Films As Highly Reflective Mirrors In The Euv, David D. Allred, William R. Evans, Jed E. Johnson, Richard L. Sandberg, R. Steven Turley Jan 2005

Thorium-Based Thin Films As Highly Reflective Mirrors In The Euv, David D. Allred, William R. Evans, Jed E. Johnson, Richard L. Sandberg, R. Steven Turley

Faculty Publications

As applications for extreme ultraviolet (EUV) radiation have been identified, the demand for better optics has also increased. Thorium and thorium oxide thin films (19 to 61 nm thick) were RF-sputtered and characterized using atomic force microscopy (AFM), spectroscopic ellipsometry, low-angle x-ray diffraction (LAXRD), x-ray photoelectron spectroscopy (XPS), and x-ray absorption near edge structure (XANES) in order to assess their capability as EUV reflectors. Their reflectance and absorption at different energies were also measured and analyzed at the Advanced Light Source in Berkeley. The reflectance of oxidized thorium is reported between 2 and 32 nm at 5, 10, and 15 …

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Prioritization Methods For Accelerating Mdp Solvers, Kevin Seppi, David Wingate Jan 2005

Prioritization Methods For Accelerating Mdp Solvers, Kevin Seppi, David Wingate

Faculty Publications

The performance of value and policy iteration can be dramatically improved by eliminating redundant or useless backups, and by backing up states in the right order. We study several methods designed to accelerate these iterative solvers, including prioritization, partitioning, and variable reordering. We generate a family of algorithms by combining several of the methods discussed, and present extensive empirical evidence demonstrating that performance can improve by several orders of magnitude for many problems, while preserving accuracy and convergence guarantees.

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Autonomous Vehicle Technologies For Small Fixed-Wing Uavs, Randal Beard, Derek Kingston, Morgan Quigley, Deryl Snyder, Reed Christiansen, Walt Johnson, Timothy Mclain, Michael A. Goodrich Jan 2005

Autonomous Vehicle Technologies For Small Fixed-Wing Uavs, Randal Beard, Derek Kingston, Morgan Quigley, Deryl Snyder, Reed Christiansen, Walt Johnson, Timothy Mclain, Michael A. Goodrich

Faculty Publications

The objective of this paper is to describe the design and implementation of a small semi-autonomous fixed-wing unmanned air vehicle. In particular we describe the hardware and software architectures used in the design. We also describe a low weight, low cost autopilot developed at Brigham Young University and the algorithms associated with the autopilot. Novel PDA and voice interfaces to the UAV are described. In addition, we overview our approach to real-time path planning, trajectory generation, and trajectory tracking. The paper is augmented with movie files that demonstrate the functionality of the UAV and its control software.

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Measurement Of Charm Fragmentation Ratios And Fractions In Photoproduction At Hera, S. Chekanov, M. Derrick, S. Magill, S. Miglioranzi, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, N. Pavel, A. G. Yagües Molina, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, A. Polini Jan 2005

Measurement Of Charm Fragmentation Ratios And Fractions In Photoproduction At Hera, S. Chekanov, M. Derrick, S. Magill, S. Miglioranzi, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, N. Pavel, A. G. Yagües Molina, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, A. Polini

Faculty Publications

© 2005, Springer New York LLC. All rights reserved. The production of D∗+, D0, D+, D+s and Λ+c charm hadrons and their antiparticles in ep scattering at HERA was measured with the ZEUS detector using an integrated luminosity of 79 pb−1. The measurement has been performed in the photoproduction regime with the exchanged-photon virtuality Q2 < 1GeV2 and for photon-proton centre-of-mass energies in the range 130 3.8GeV and pseudorapidity |η(D,Λc)| < 1.6. The production cross sections were used to determine the ratio of neutral and charged D-meson production rates, Ru/d, the strangeness-suppression factor, γs, and the fraction of charged D mesons produced in a vector state, Pdv. The measured Ru/d and γs values agree with those obtained in deep inelastic scattering and in e+e- annihilations. The measured Pdv value is smaller than, but consistent with, the previous measurements. The fractions of c quarks hadronising as a particular charm hadron, f(c → D, Λc), were derived in the given kinematic range. The measured open-charm fragmentation fractions are consistent with previous results, although the measured f(c → D*+) is smaller and f(c → Λ+c) is larger than those obtained in e+e- annihilations. These results generally support the hypothesis that fragmentation proceeds independently of the hard sub-process.

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The Effects Of Satellite-Derived Vegetation Cover Variability On Simulated Land–Atmosphere Interactions In The Nams, Toshi Matsui, Venkataraman Lakshmi, Eric Small Jan 2005

The Effects Of Satellite-Derived Vegetation Cover Variability On Simulated Land–Atmosphere Interactions In The Nams, Toshi Matsui, Venkataraman Lakshmi, Eric Small

Faculty Publications

Substantial evolution of Normalized Difference Vegetation Index (NVDI)-derived vegetation cover (Fg)exists in the southwestern United States and Mexico. The intraseasonal and wet-/dry-year fluctuations of Fgare linked to observed precipitation in the North American monsoon system (NAMS). The manner in whichthe spatial and temporal variability of Fg influences the land–atmosphere energy and moisture fluxes, andassociated likelihood of moist convection in the NAMS regions, is examined. For this, the regional climatemodel (RCM) is employed, with three different Fg boundary conditions to examine the influence ofintraseasonal and wet-/dry-year vegetation variability. Results show that a strong link exists between evaporativefraction (EF), surface temperature, and …

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New Standards For Reducing Gravity Data: The North American Gravity Database, William J. Hinze, Carlos Aiken, John Brozena, Bernard Coakley, David Dater, Guy Flanagan, Rene Forsberg, Thomas Hildenbrand, G. Randy Keller, James N. Kellogg, Robert Kucks, Xiong Li, Andre Mainville, Robert Morin, Mark Pilkington, Donald Plouff, Dhananjay Ravat, Daniel Roman, Jamie Urrutia-Fucugauchi, Marc Veronneau, Michael Webring, Daniel Winester Jan 2005

New Standards For Reducing Gravity Data: The North American Gravity Database, William J. Hinze, Carlos Aiken, John Brozena, Bernard Coakley, David Dater, Guy Flanagan, Rene Forsberg, Thomas Hildenbrand, G. Randy Keller, James N. Kellogg, Robert Kucks, Xiong Li, Andre Mainville, Robert Morin, Mark Pilkington, Donald Plouff, Dhananjay Ravat, Daniel Roman, Jamie Urrutia-Fucugauchi, Marc Veronneau, Michael Webring, Daniel Winester

Faculty Publications

The North American gravity database as well as databases from Canada, Mexico, and the United States are being revised to improve their coverage, versatility, and accuracy. An important part of this effort is revising procedures for calculating gravity anomalies, taking into account our enhanced computational power, improved terrain databases and datums, and increased interest in more accurately defining long-wavelength anomaly components. Users of the databases may note minor differences between previous and revised database values as a result of these procedures. Generally, the differences do not impact the interpretation of local anomalies but do improve regional anomaly studies. The most …

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A Bayesian Technique For Task Localization In Multiple Goal Markov Decision Processes, James Carroll, Kevin Seppi Dec 2004

A Bayesian Technique For Task Localization In Multiple Goal Markov Decision Processes, James Carroll, Kevin Seppi

Faculty Publications

In a reinforcement learning task library system for Multiple Goal Markov Decision Process (MGMDP), localization in the task space allows the agent to determine whether a given task is already in its library in order to exploit previously learned experience. Task localization in MGMDPs can be accomplished through a Bayesian approach, however a trivial approach fails when the rewards are not distributed normally. This can be overcome through our Bayesian Task Localization Technique (BTLT).

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Variable Resolution Discretization In The Joint Space, Christopher K. Monson, Kevin Seppi, David Wingate, Todd S. Peterson Dec 2004

Variable Resolution Discretization In The Joint Space, Christopher K. Monson, Kevin Seppi, David Wingate, Todd S. Peterson

Faculty Publications

We present JoSTLe, an algorithm that performs value iteration on control problems with continuous actions, allowing this useful reinforcement learning technique to be applied to problems where a priori action discretization is inadequate. The algorithm is an extension of a variable resolution technique that works for problems with continuous states and discrete actions. Results are given that indicate that JoSTLe is a promising step toward reinforcement learning in a fully continuous domain.

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Sm2Nairo6, A Monoclinically Distorted Double Perovskite, Samuel J. Mugavero Iii, Irina V. Puzdrjakova, Mark D. Smith, Hans-Conrad Zur Loye Dec 2004

Sm2Nairo6, A Monoclinically Distorted Double Perovskite, Samuel J. Mugavero Iii, Irina V. Puzdrjakova, Mark D. Smith, Hans-Conrad Zur Loye

Faculty Publications

Single crystals of the lanthanide-containing iridate, disamarium sodium iridium hexaoxide, Sm2NaIrO6, were prepared via high-temperature flux growth and structurally characterized by single-crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P21/n and is a double perovskite, consisting of a 1:1 ordered rock-salt-type lattice of corner-shared NaO6 and IrO6 distorted octahedra. Samarium occupies the eightfold coordination site generated by the connectivity of the octahedra.

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Hyperbolic Sets That Are Not Locally Maximal, Todd L. Fisher Dec 2004

Hyperbolic Sets That Are Not Locally Maximal, Todd L. Fisher

Faculty Publications

This paper addresses the following topics relating to the structure of hyperbolic sets: First, hyperbolic sets that are not contained in locally maximal hyperbolic sets. Second, the existence of a Markov partition for a hyperbolic set. We construct new examples of hyperbolic sets which are not contained in locally maximal hyperbolic sets. The first example is robust under perturbations and can be constructed on any compact manifold of dimension greater than one. The second example is robust, topologically transitive, and constructed on a 4-dimensional manifold. The third example is volume preserving and constructed on R4. We show that every hyperbolic …

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