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2001

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Articles 241 - 270 of 3030

Full-Text Articles in Physical Sciences and Mathematics

Field Evaluation Of Sounding Accuracy In Deep Water Multibeam Swath Bathymetry, Christian De Moustier Nov 2001

Field Evaluation Of Sounding Accuracy In Deep Water Multibeam Swath Bathymetry, Christian De Moustier

Center for Coastal and Ocean Mapping

A new Kongsberg-Simrad EM120 multibeam echo-sounder has been installed aboard Scripps Institution of Oceanography's Research Vessel Roger Revelle in January 2001. This system can map reliably a 20 km swath of seafloor in 4000 m water depth with 191 soundings per ping. Such a wide swath width demands highly accurate (<0.05' RMS) roll information from a motion sensor, and makes estimating sounding accuracy across the swath an interesting challenge. It is shown that good accuracy estimates can be obtained by collecting data on station under control of the GPS-aided dynamic positioning system usually available on most modern long-range oceanographic vessels. A number of motion sensors, with RMS roll accuracy specifications ranging from 0.05' to 0.01' ,were tested with the EM120 sonar on station in 3800 m to 4000 m water depths. Unexpectedly, they yielded roughly the same depth uncertainty as a function of receive beam angle. This result might be explained by synchronization errors between the attitude data and the sonar data leading to beam pointing errors, other types of beam pointing errors, a range of roll accuracy narrower than specified for the motion sensors, or a combination of these factors

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Geozui3d: Data Fusion For Interpreting Oceanographic Data, Colin Ware, Matthew D. Plumlee, Roland J. Arsenault, Larry A. Mayer, Shep M. Smith Lt, Donald H. House Nov 2001

Geozui3d: Data Fusion For Interpreting Oceanographic Data, Colin Ware, Matthew D. Plumlee, Roland J. Arsenault, Larry A. Mayer, Shep M. Smith Lt, Donald H. House

Center for Coastal and Ocean Mapping

GeoZui3D stands for Geographic Zooming User Interface. It is a new visualization software system designed for interpreting multiple sources of 3D data. The system supports gridded terrain models, triangular meshes, curtain plots, and a number of other display objects. A novel center of workspace interaction method unifies a number of aspects of the interface. It creates a simple viewpoint control method, it helps link multiple views, and is ideal for stereoscopic viewing. GeoZui3D has a number of features to support real-time input. Through a CORBA interface external entities can influence the position and state of objects in the display. Extra …

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Comments On “Errors In The Estimate Of The Fractal Correlation Dimension Of Raindrop Spatial Distribution”, A. R. Jameson, Alexander Kostinski Nov 2001

Comments On “Errors In The Estimate Of The Fractal Correlation Dimension Of Raindrop Spatial Distribution”, A. R. Jameson, Alexander Kostinski

Department of Physics Publications

No abstract provided.

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Gasoline Consumption Attributable To Gasoline Powered Watercraft Use In Maine, Jonathan Rubin, Charles Morrris, Suzanne K. Hart Nov 2001

Gasoline Consumption Attributable To Gasoline Powered Watercraft Use In Maine, Jonathan Rubin, Charles Morrris, Suzanne K. Hart

Economic Development

This study was conducted by the Margaret Chase Smith Center for Public Policy (MCSC) of the University of Maine at the request of the Maine Legislature’s Commission to Study Equity in the Distribution of Gas Tax Revenues Attributable to Snowmobiles, All-Terrain Vehicles and Watercraft. The Commission was created by the Legislature with a charge to collect and analyze information to determine an equitable distribution of gas tax revenues used in the enforcement and enhancement of programs supporting off-road vehicle use in Maine. The Commission concluded that snowmobiling, boating and ATV use has increased significantly over recent years and now constitutes …

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Synthesis Of A New Hollandite-Type Manganese Oxide With Framework And Interstitial Cr(Iii), Stanton Ching, Peter F. Driscoll, Katarzyna S. Krukowska, Michael R. Marvel, Steven L. Suib Nov 2001

Synthesis Of A New Hollandite-Type Manganese Oxide With Framework And Interstitial Cr(Iii), Stanton Ching, Peter F. Driscoll, Katarzyna S. Krukowska, Michael R. Marvel, Steven L. Suib

Chemistry Faculty Publications

Hollandite with Cr(III) in both tunnel and framework sites has been prepared hydrothermally from layered manganese oxide precursors.

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Monitoring Subsurface Drainage Flow At Remote Locations, Stephen R. Workman, Stephen F. Higgins, Scott A. Shearer Nov 2001

Monitoring Subsurface Drainage Flow At Remote Locations, Stephen R. Workman, Stephen F. Higgins, Scott A. Shearer

Biosystems and Agricultural Engineering Faculty Publications

Laboratory evaluations and field results are presented for a slotted weir used to measure discharge from subsurface drains. The head–discharge curve for the vertical slot is a simple power function with an exponent of 1.5. There was excellent agreement (r2 > 0.99 and 1:1 slope) between predicted and observed discharge in laboratory testing of 12 test weirs representing five slot widths. The primary advantages of the vertical slot weir are its simplicity, ease of maintenance, and ability to measure small flow rates. Disadvantages include a tendency for the slot to close a small amount over time as a result of …

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Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 18, Number 3, November 2001, College Of Engineering And Computer Science, Wright State University Nov 2001

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 18, Number 3, November 2001, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

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Bronx River Restoration: Report And Assessment, Nicole Marshall Nov 2001

Bronx River Restoration: Report And Assessment, Nicole Marshall

Student Theses 2001-2013

No abstract provided.

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Developing Haptic And Visual Perceptual Categories For Reaching And Grasping With A Humanoid Robot, Jefferson Coelho, Justus Piater, Roderic Grupen Nov 2001

Developing Haptic And Visual Perceptual Categories For Reaching And Grasping With A Humanoid Robot, Jefferson Coelho, Justus Piater, Roderic Grupen

Roderic Grupen

Properties of the human embodiment sensorimotor apparatus and neurological structure participate directly in the growth and development of cognitive processes against enormous worst case complexity. It is our position that relationships between morphology and perception over time lead to incerasingly comprehensive models that describe the agent's relationship to the world.We are applying insight derived from neuroscience, neurology, and developmental psychology to the design of advanced robot architectures. To investigate developmental processes, we have begun to approximate the human sensorimotor configuration and to engage sensory and motor subsystems in developmental sequences. Many such sequences have been documented in studies of infant …

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Poly Millennial 2000 Hilton Waikoloa Villages, Hawaii, December 9-13, 2000, Otto Vogl, William Daly Nov 2001

Poly Millennial 2000 Hilton Waikoloa Villages, Hawaii, December 9-13, 2000, Otto Vogl, William Daly

Otto Vogl

No abstract provided.

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Classical Density Functional Theory Of Freezing In Simple Fluids: Numerically Induced False Solutions, M. Valera, F. J. Pinski, Duane D. Johnson Nov 2001

Classical Density Functional Theory Of Freezing In Simple Fluids: Numerically Induced False Solutions, M. Valera, F. J. Pinski, Duane D. Johnson

Duane D. Johnson

Density functional theory (DFT) has provided many insights into the freezing of simple fluids. Several analytical and numerical solution have shown that the DFT provides an accurate description of freezing of hard spheres and their mixtures. Compared to other techniques, numerical, grid-based algorithms for solving the DFT equations have more variational freedom and are capable of describing subtle behavior, as that seen in mixtures with multipeaked density profiles. However the grid-based approach is sensitive to the coarseness of the mesh employed. Here we summarize how the granularity of the mesh affects the freezing point within the DFT. For coarse meshes, …

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Climatology Of Mid- And Low-Latitude F Region Disturbance Winds Measured By Windii, J. T. Emmert, Bela G. Fejer, C. G. Fesen, G. G. Shepherd, B. H. Solheim Nov 2001

Climatology Of Mid- And Low-Latitude F Region Disturbance Winds Measured By Windii, J. T. Emmert, Bela G. Fejer, C. G. Fesen, G. G. Shepherd, B. H. Solheim

Bela G. Fejer

No abstract provided.

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Marginal And Parametric Analysis Of The Central Optimal Solution, Allen G. Holder, J F. Sturm, S Zhang Nov 2001

Marginal And Parametric Analysis Of The Central Optimal Solution, Allen G. Holder, J F. Sturm, S Zhang

Mathematics Faculty Research

In this paper we investigate the sensitivity analysis of the parameterized central path. First, a complete marginal analysis of the central optimal solution is developed. This analysis explains the differential properties of the central optimal solution with respect to both the cost coefficients and the right-hand side components. We also show that the marginal derivatives are uniformly bounded. Second, we present three conditions for which the parameterized central path converges. Two of these results allow the difficult situation of simultaneous perturbations in the cost coefficients and right-hand side levels.

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Micromagnetics Simulation Of Deep-Submicron Supermalloy Disks, Scott Whittenburg Nov 2001

Micromagnetics Simulation Of Deep-Submicron Supermalloy Disks, Scott Whittenburg

Chemistry Faculty Publications

The results of recent micromagnetic simulations of deep submicron supermalloy disks are presented. A recent experimental measurement of the hysteresis and magnetic domain structure in supermalloy disks with diameters ranging from 55 to 500 nm and thickness ranging from 6 to 15 nm has been reported. Our micromagnetic simulations show remarkable agreement with the experimental hysteresis loops. The simulation results show that for thin or small diameter disks a single magnetic domain exists with all spins aligned. The hysteresis loop represents free rotation of these spins. For larger diameter disks or as the thickness increases the hysteresis loops change shape …

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"Selective" Pesticides: Are They Less Hazardous To The Environment?, John D. Stark, John Banks Nov 2001

"Selective" Pesticides: Are They Less Hazardous To The Environment?, John D. Stark, John Banks

SIAS Faculty Publications

No abstract provided.

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New Results On Frame-Proof Codes And Traceability Schemes, R. Safavi-Naini, Yejing Wang Nov 2001

New Results On Frame-Proof Codes And Traceability Schemes, R. Safavi-Naini, Yejing Wang

Faculty of Informatics - Papers (Archive)

In this correspondence we derive lower bounds on the maximum number of codewords in a class of frame-proof codes and traceability schemes, and give constructions for both with more codewords than the best known.

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Function Spaces And Multiplier Operators, R. Nillsen, S. Okada Nov 2001

Function Spaces And Multiplier Operators, R. Nillsen, S. Okada

Faculty of Informatics - Papers (Archive)

Let G denote a locally compact Hausdorff abelian group. Then a bounded linear operator T from L^2(G) into L^2(G) is a bounded multiplier operator if, under the Fourier transform on L^2(G ), for each function f in L^2(G), T(f) changes into a bounded function U times the Fourier transform of f. Then U is called the multiplier of T. An unbounded multiplier operator has a similar definition, but its domain is a dense subspace of L^2(G) and the multiplier function need not be bounded. For example, differentiation on the first order Sobolev subspace of L^2(R) is an unbounded multiplier operator …

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Parameter Synthesis Of Higher Kinematic Planars, Min-Ho Kyung, Elisha Sacks Nov 2001

Parameter Synthesis Of Higher Kinematic Planars, Min-Ho Kyung, Elisha Sacks

Department of Computer Science Technical Reports

No abstract provided.

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A Round Trip Time And Timeout Aware Traffic Conditioner For Differentiated Services Networks, Ahsan Habib, Bharat Bhargava, Sonia Fahmy Nov 2001

A Round Trip Time And Timeout Aware Traffic Conditioner For Differentiated Services Networks, Ahsan Habib, Bharat Bhargava, Sonia Fahmy

Department of Computer Science Technical Reports

No abstract provided.

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Variational Transition State Theory Evaluation Of The Rate Constant For Proton Transfer In A Polar Solvent, Robin P. Mcrae, Gregory K. Schenter, Bruce C. Garrett, Zoran Svetlicic, Donald G. Truhlar Nov 2001

Variational Transition State Theory Evaluation Of The Rate Constant For Proton Transfer In A Polar Solvent, Robin P. Mcrae, Gregory K. Schenter, Bruce C. Garrett, Zoran Svetlicic, Donald G. Truhlar

Chemistry and Biochemistry Faculty Publications

Variational transition state theory (VTST) is used to calculate rate constants for a model proton transfer reaction in a polar solvent. We start from an explicit description of the reacting solute in a solvent, and we model the effects of solvation on the reaction dynamics by a generalized Langevin equation (GLE) for the solute. In this description, the effects of solvation on the reaction energetics are included in the potential of mean force, and dynamical, or nonequilibrium, solvation is included by solvent friction. The GLE solvation dynamics are approximated by a collection of harmonic oscillators that are linearly coupled to …

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A Note On Visualizing Response Transformations In Regression, R. Dennis Cook, David J. Olive Nov 2001

A Note On Visualizing Response Transformations In Regression, R. Dennis Cook, David J. Olive

Articles and Preprints

A new graphical method for assessing parametric transformations of the response in linear regression is given. Simply regress the response variable Y on the predictors and find the fitted values. Then dynamically plot the transformed response Y(λ) against those fitted values by varying the transformation parameter λ until the plot is linear. The method can also be used to assess the success of numerical response transformation methods and to discover influential observations. Modifications using robust estimators can be used as well.

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Comparison Of Stellar Angular Diameters From The Npoi, The Mark Iii Optical Interferometer, And The Infrared Flux Method, Tyler E. Nordgren, Jeffrey J. Sudol, D. Mozurkewich Nov 2001

Comparison Of Stellar Angular Diameters From The Npoi, The Mark Iii Optical Interferometer, And The Infrared Flux Method, Tyler E. Nordgren, Jeffrey J. Sudol, D. Mozurkewich

Physics & Engineering Faculty Publications

No abstract provided.

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A Robotic Wide-Angle Hα Survey Of The Southern Sky, John E. Gaustad, P. R. Mccullough, W. Rosing, D. Van Buren Nov 2001

A Robotic Wide-Angle Hα Survey Of The Southern Sky, John E. Gaustad, P. R. Mccullough, W. Rosing, D. Van Buren

Physics & Astronomy Faculty Works

We have completed a robotic wide-angle imaging survey of the southern sky (delta = +15 degrees to -90 degrees) at 656.3 nm wavelength, the H alpha emission line of hydrogen. Each image of the resulting Southern H alpha Sky Survey Atlas (SHASSA) covers an area of the sky 13 degrees square at an angular resolution of approximately 0.'8 and reaches a sensitivity level of 2 R (1.2 x 10(-17) ergs cm(-2) s(-1) arcsec(-2)) pixel(-1), corresponding to an emission measure of 4 cm(-6) pc and to a brightness temperature for microwave free-free emission of 12 muK at 30 GHz. Smoothing over …

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Three-Body Coulomb Problem Probed By Mapping The Bethe Surface In Ionizing Ion-Atom Collisions, Robert Moshammer, Appathurai N. Perumal, Michael Schulz, V. D. Rodriguez, Holger Kollmus, Rido Mann, Siegbert Hagmann, Joachim Hermann Ullrich Nov 2001

Three-Body Coulomb Problem Probed By Mapping The Bethe Surface In Ionizing Ion-Atom Collisions, Robert Moshammer, Appathurai N. Perumal, Michael Schulz, V. D. Rodriguez, Holger Kollmus, Rido Mann, Siegbert Hagmann, Joachim Hermann Ullrich

Physics Faculty Research & Creative Works

The three-body Coulomb problem has been explored in kinematically complete experiments on single ionization of helium by 100 MeV / u C 6 + and 3.6 MeV / u u 5 3 + impact. Low-energy electron emission (E e < 150 eV ) as a function of the projectile deflection ϑ p (momentum transfer), i.e., the Bethe surface [[15]], has been mapped with Δ ϑ p ± 25 nanoradian resolution at extremely large perturbations (3.6 MeV / uAu53+ ) where single ionization occurs at impact parameters of typically 10 times the He K -shell radius. The experimental data are not in agreement with state-of-the-art continuum distorted wave-eikonal initial state theory.

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Electron-Impact Excitation To The 4p⁵5s And 4p⁵5p Levels Of Kr | Using Different Distorted-Wave And Close-Coupling Methods, Arati K. Dasgupta, Klaus Bartschat, D. Vaid, Alexei N. Grum-Grzhimailo, Don H. Madison, Milan Blaha, John L. Giuliani Nov 2001

Electron-Impact Excitation To The 4p⁵5s And 4p⁵5p Levels Of Kr | Using Different Distorted-Wave And Close-Coupling Methods, Arati K. Dasgupta, Klaus Bartschat, D. Vaid, Alexei N. Grum-Grzhimailo, Don H. Madison, Milan Blaha, John L. Giuliani

Physics Faculty Research & Creative Works

Electron-impact excitation of the 4p55s and 4p55p levels of Kr I has been investigated in detail by calculating cross sections using distorted-wave and close-coupling approaches. The results are presented from the excitation thresholds up to 50 eV incident energy. They are contrasted among the different calculations and compared with other theoretical predictions and experimental data. Significant disagreement is found with many of the recent experimental data of Chilton et al. [Phys. Rev. A 62, 032714 (2000)].

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Marginal Regression Of Gaps Between Recurrent Events, Yijian Huang, Ying Qing Chen Nov 2001

Marginal Regression Of Gaps Between Recurrent Events, Yijian Huang, Ying Qing Chen

U.C. Berkeley Division of Biostatistics Working Paper Series

Recurrent event data typically exhibit the phenomenon of intra-individual correlation, owing to not only observed covariates but also random effects. In many applications, the population can be reasonably postulated as a heterogeneous mixture of individual renewal processes, and the inference of interest is the effect of individual-level covariates. In this article, we suggest and investigate a marginal proportional hazards model for gaps between recurrent events. A connection is established between observed gap times and clustered survival data, however, with informative cluster size. We then derive a novel and general inference procedure for the latter, based on a functional formulation of …

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Modeling Control Of Hiv Infection Through Structured Treatment Interruptions With Recommendations For Experimental Protocol, Shannon Kubiak, Heather Lehr, Rachel Levy, Todd Moeller, Albert Parker, Edward Swim Nov 2001

Modeling Control Of Hiv Infection Through Structured Treatment Interruptions With Recommendations For Experimental Protocol, Shannon Kubiak, Heather Lehr, Rachel Levy, Todd Moeller, Albert Parker, Edward Swim

All HMC Faculty Publications and Research

Highly Active Anti-Retroviral Therapy (HAART) of HIV infection has significantly reduced morbidity and mortality in developed countries. However, since these treatments can cause side effects and require strict adherence to treatment protocol, questions about whether or not treatment can be interrupted or discontinued with control of infection maintained by the host immune system remain to be answered. We present sensitivity analysis of a compartmental model for HIV infection that allows for treatment interruptions, including the sensitivity of the compartments themselves to our parameters as well as the sensitivity of the cost function used in parameter estimation. Recommendations are made about …

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The Probe, Issue 219 – November/December 2001 Nov 2001

The Probe, Issue 219 – November/December 2001

The Probe: Newsletter of the National Animal Damage Control Association

Oversight of Wildlife Damage Control Operators
Oversight of the Wildlife Control Industry -- Tim Mien, President, NWCOA
Oversight of the Wildlife Control Industry: Regulatory and Statutory Standards as Recommendations to the States -- John Hadidian & Michele Childs, The Humane Society of the United States
Coyote Attacks Increasing in California -- Nicki Frey
Ranchers, hunters, farmers and environmentalists in eastern Idaho have agreed to a plan for managing grizzly bears in the state should they be removed from the federal Endangered Species list.
Bobby R. Acord is the new Administrator for the USDA Animal and Plant Health Inspection Service.
Graduate …

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Knowledge Discovery In Biological Datasets Using A Hybrid Bayes Classifier/Evolutionary Algorithm, Michael L. Raymer, Leslie A. Kuhn, William F. Punch Nov 2001

Knowledge Discovery In Biological Datasets Using A Hybrid Bayes Classifier/Evolutionary Algorithm, Michael L. Raymer, Leslie A. Kuhn, William F. Punch

Kno.e.sis Publications

A key element of bioinformatics research is the extraction of meaningful information from large experimental data sets. Various approaches, including statistical and graph theoretical methods, data mining, and computational pattern recognition, have been applied to this task with varying degrees of success. We have previously shown that a genetic algorithm coupled with a k-nearest-neighbors classifier performs well in extracting information about protein-water binding from X-ray crystallographic protein structure data. Using a novel classifier based on the Bayes discriminant function, we present a hybrid algorithm that employs feature selection and extraction to isolate salient features from large biological data sets. The …

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Local Impurity-Assisted Conductance In Magnetic Tunnel Junctions, Evgeny Y. Tsymbal, David G. Pettifor Nov 2001

Local Impurity-Assisted Conductance In Magnetic Tunnel Junctions, Evgeny Y. Tsymbal, David G. Pettifor

Evgeny Tsymbal Publications

Using a simple tight-binding model and the Kubo formula we have calculated the lateral distribution of the tunneling conductance across a magnetic tunnel junction probed by STM. We find that the presence of an isolated impurity within the barrier layer can cause a spike in the conductance distribution, which is in agreement with recent experiments. We show that the local tunneling magnetoresistance (TMR) is very sensitive to the electronic state of the impurity and to the lateral position of the tip. The latter dramatic variation in TMR could be detected by STM.

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