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1999

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Articles 871 - 900 of 2348

Full-Text Articles in Physical Sciences and Mathematics

Hydrologic Time Series Forecasting With Specialized Autoregressive Neural Networks, Paul Edward Roundy May 1999

Hydrologic Time Series Forecasting With Specialized Autoregressive Neural Networks, Paul Edward Roundy

Undergraduate Honors Capstone Projects

Interannual forecasts of hydrologic time series are important for water supply management.  Specialized neural network algorithms for such forecasts are developed here.  These methods are based on  the principles of nonlinear dynamics and an autoregresive backpropogation training algorithm.  The applicable nonlinear methods are described, as well as the algorithm.  Some of the problems of these networks are summarized, along with some of their positive attributes.  Tests showed that they may be able to learn and forecast some hydrologic data.  These networks were most successful for  forecasting the flows of the Colorado River.  Some example forecasts are given, including the peaks …

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Vessiot: A Maple Package For Varational And Tensor Calculus In Multiple Coordinate Frames, Charles E. Miller May 1999

Vessiot: A Maple Package For Varational And Tensor Calculus In Multiple Coordinate Frames, Charles E. Miller

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Maple V package Vessiot is an extensive set of procedures for performing computations in variational and tensor calculus. Vessiot is an extension of a previous package, Helmholtz, which was written by Cinnamon Hillyard for performing operations in the calculus of variations. The original set of commands included standard operators on differential forms, Euler-Lagrange operators, the Lie bracket operator, Lie derivatives, and homotopy operators. These capabilities are preserved in Vessiot, and enhanced so as to function in a multiple coordinate frame context. In addition, a substantial number of general tensor operations have been added to the package. These include standard …

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Black Holes And The Sym Diagram. Ii, Emil Martinec, Vatche Sahakian May 1999

Black Holes And The Sym Diagram. Ii, Emil Martinec, Vatche Sahakian

All HMC Faculty Publications and Research

The complete phase diagram of objects in M theory compactified on tori Tp,p=1,2,3, is elaborated. Phase transitions occur when the object localizes on cycle(s) (the Gregory-Laflamme transition), or when the area of the localized part of the horizon becomes one in string units (the Horowitz-Polchinski correspondence point). The low-energy, near-horizon geometry that governs a given phase can match onto a variety of asymptotic regimes. The analysis makes it clear that the matrix conjecture is a special case of the Maldacena conjecture.

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An On-Line Test For Polycyclic Aromatic Hydrocarbons In The Flue Gas From Coal Combustion In An Fbc System, Wenjun Han May 1999

An On-Line Test For Polycyclic Aromatic Hydrocarbons In The Flue Gas From Coal Combustion In An Fbc System, Wenjun Han

Masters Theses & Specialist Projects

Polycyclic Aromatic Hydrocarbons (PAHs) are environmental pollutants that have received considerable attention because of their carcinogenic and mutagenic effects. Due to the extensive amount of data suggesting the hazards of these compounds, 16 PAHs are on the Environmental Protection Agency (EPA) Priority Pollutant List. These compounds are often emitted into the atmosphere by way of combustion processes. Thus, analysis of these compounds during coal combustion is an important task. Three 1000-hour coal combustion burns were performed using the 0.1 MW (0.3 m) bench-scale Fluidized Bed Combustor (FBC) in the Combustion Laboratory at Western Kentucky University. The data for this thesis …

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Does Tall Grass Reduce Bird Numbers On Airports?: Results Of Pen Test With Canada Geese And Field Trials At Two Airports, 1998, Thomas W. Seamans, Richard A. Dolbeer, Mark S. Carrara, Richard B. Chipman May 1999

Does Tall Grass Reduce Bird Numbers On Airports?: Results Of Pen Test With Canada Geese And Field Trials At Two Airports, 1998, Thomas W. Seamans, Richard A. Dolbeer, Mark S. Carrara, Richard B. Chipman

Bird Strike Committee-USA/Canada Joint Annual Meeting: 1st (1999)

A suggested management plan to reduce bird numbers and bird-aircraft collisions at airports is to maintain grass 15-25 cm high. However, 3 studies conducted in the United States in 1998 indicated tall-grass management may not result in fewer birds. First, Canada geese (Branta canadensis), in a replicated experiment lasting 9 days in 6 pens in Ohio, showed no preference (P = 0.53) for short-grass (4-11 cm) over tall-grass (16-21 cm) plots. Second, we compared bird use of 8 tall- (23.3 ± 0.5 cm high, x ± SE) and 8 short- (14.3 ± 0.2) grass plots totaling 46 ha at Burke …

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Center For Sustainable Agricultural Systems Newsletter, May/June 1999 May 1999

Center For Sustainable Agricultural Systems Newsletter, May/June 1999

Center for Sustainable Agricultural Systems: Newsletter (1993–2000)

Contents:

The Farmer and the Dean

University Role in Biotechnology: Who Owns Genes and Diversity?

CSAS Volume 9 Discusses Watersheds

SARE Appoints Paula Ford North Central PDP

Coordinator Policy Project Identifies Retention of Farms and Farmland as Top Priorities

Olson Heads to Kentucky

Organic Grain Farming Workshops

Two Alternative Agriculture Conferences in Midwest

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Particle Simulation In Contact Mechanics Of A Bouncing Elastic Ball, Donald Greenspan May 1999

Particle Simulation In Contact Mechanics Of A Bouncing Elastic Ball, Donald Greenspan

Mathematics Technical Papers - Archive

An elastic ball is simulated by considering lumped mass molecular sets called particles. Particles are allowed to interact only locally in a fashion similar to that employed in molecular mechanics. Under local and gravity forces an n-body problem results when initial data are prescribed. By scaling the forces, the resulting n-body problem is solved numerically using only a scientific personal computer. A variety of examples of bouncing balls are described and discussed.

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Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 5, May 1999, College Of Engineering And Computer Science, Wright State University May 1999

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 5, May 1999, 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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The Effect Of Laser Bandwidth On The Signal Detected In Two-Color, Resonant Four-Wave Mixing Spectroscopy, F. Di Teodoro, Elizabeth Mccormack May 1999

The Effect Of Laser Bandwidth On The Signal Detected In Two-Color, Resonant Four-Wave Mixing Spectroscopy, F. Di Teodoro, Elizabeth Mccormack

Physics Faculty Research and Scholarship

The effect of laser line shape and bandwidth on the signal detected in two-color, resonant four-wave mixing (TC-RFWM) spectroscopy is determined by means of an ab initio calculation of the third-order polarization based on diagrammatic perturbation theory. Modifications to the approach previously used for the case of delta-function laser line shapes are made by introducing a different treatment of the rotating wave approximation and phase-matching conditions. A three-level excitation scheme for double-resonance spectroscopy of bound and quasibound states is analyzed. In the case of Lorentzian laser line shapes, analytic expressions for the signal line profile are obtained for each excitation …

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An Investigation Into The Use Of The Virtual Reality Modelling Language (Vrml) As A Means Of Distribution Virtual Reality Tourist Information Across The World Wide Web, Hugh Mcatamney, Ciaran Mcdonnell May 1999

An Investigation Into The Use Of The Virtual Reality Modelling Language (Vrml) As A Means Of Distribution Virtual Reality Tourist Information Across The World Wide Web, Hugh Mcatamney, Ciaran Mcdonnell

Conference papers

The purpose of the work described was to investigate the use of the Virtual Reality Modelling Language (VRML) as a tool to distribute tourist information across the web. This was done by the creation of a web site containing two Virtual Reality models of tourist interest. These were then valuated using a number of techniques both online and offline. This paper describes the methods used to create and evaluate these models as well as giving a overview of some of the results obtained.

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Small Extensions Of Witt Rings, Robert W. Fitzgerald May 1999

Small Extensions Of Witt Rings, Robert W. Fitzgerald

Articles and Preprints

We consider certain Witt ring extensions S of a noetherian Witt ring R obtained by adding one new generator. The conditions on the new generator are those known to hold when R is the Witt ring of a Field F, S is the Witt ring of a Field K and K/F is an odd degree extension. We show that if R is of elementary type then so is S.

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Kinematics Of Tt̅ Events At Cd, F. Abe, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration May 1999

Kinematics Of Tt̅ Events At Cd, F. Abe, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

The kinematic properties of tt̅ events are studied in the W + multijet channel using data collected with the CDF detector during the 1992–1995 runs at the Fermilab Tevatron collider corresponding to an integrated luminosity of 109 pb-1. Distributions of a variety of kinematic variables chosen to be sensitive to different aspects of tt̅ production are compared with those expected from Monte Carlo calculations. A sample of 34 events rich in tt̅ pairs is obtained by requiring at least one jet identified by the silicon vertex detector (SVX) as having a displaced vertex consistent with the decay of …

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Image Fusion Using Autoassociative-Heteroassociative Neural Networks, Claudia V. Kropas-Hughes May 1999

Image Fusion Using Autoassociative-Heteroassociative Neural Networks, Claudia V. Kropas-Hughes

Theses and Dissertations

Images are easily recognized, classified, and segmented; in short, analyzed by humans. The human brain/nervous system; the biological computer, performs rapid and accurate image processing. In the current research the concepts of the biological neural system provide the impetus for developing a computational means of fusing image data. Accomplishing this automatic image processing requires features be extracted from each image data set, and the information content fused. Biologically inspired computational models are examined for extracting features by transformations such as Fourier, Gabor, and wavelets, and for processing and fusing the information from multiple images through evaluation of autoassociative neural networks …

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Modes And Quasi-Modes For M = 1,2 In A Gyrokinetic Model For A Non-Neutral Plasma, S. Neil Rasband, Ross L. Spencer May 1999

Modes And Quasi-Modes For M = 1,2 In A Gyrokinetic Model For A Non-Neutral Plasma, S. Neil Rasband, Ross L. Spencer

Faculty Publications

Modes and quasi-modes for m = 1,2 are studied in a gyro-kinetic model for a pure-electron plasma. Only z-independent perturbations are considered. Numerical methods are used to solve the relevant differential equations for smooth, analytic density profiles. Different temperatures and representative profiles are considered and comparison is made with the familiar cold fluid model from which the results depart but little, except at higher temperatures. A continuum component to the spectrum, present in the cold-fluid model, remains in the gyro-kinetic model to the order considered.

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Near-Field Fluorescence Microscopy Based On Two-Photon Excitation With Metal Tips, Erik J. Sánchez, Lukas Novotny, X. Sunney Xie May 1999

Near-Field Fluorescence Microscopy Based On Two-Photon Excitation With Metal Tips, Erik J. Sánchez, Lukas Novotny, X. Sunney Xie

Physics Faculty Publications and Presentations

We present a new scheme for near-field fluorescence imaging using a metal tip illuminated with femtosecond laser pulses of proper polarization. The strongly enhanced electric field at the metal tip (ap15 nm end diameter) results in a localized excitation source for molecular fluorescence. Excitation of the sample via two-photon absorption provides good image contrast due to the quadratic intensity dependence. The spatial resolution is shown to be better than that of the conventional aperture technique. We used the technique to image fragments of photosynthetic membranes, as well as j-aggregates with spatial resolutions on the order of 20 nm.

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Observations Of Decarboxylation In Group 6 Complexes With Amino Acid Schiff Base Ligands, Julia J. Pilloni May 1999

Observations Of Decarboxylation In Group 6 Complexes With Amino Acid Schiff Base Ligands, Julia J. Pilloni

College Honors Program

No abstract provided.

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Insight Into The Selectivity Of Molecular Imprinted Polymers, Thomas Patrick O'Brien May 1999

Insight Into The Selectivity Of Molecular Imprinted Polymers, Thomas Patrick O'Brien

Seton Hall University Dissertations and Theses (ETDs)

.

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The Decomposition Theorem For Two-Dimensional Shifts Of Finite Type, Aimee S. A. Johnson, K. M. Madden May 1999

The Decomposition Theorem For Two-Dimensional Shifts Of Finite Type, Aimee S. A. Johnson, K. M. Madden

Mathematics & Statistics Faculty Works

A one-dimensional shift of finite type can be described as the collection of bi-infinite "walks" along an edge graph. The Decomposition Theorem states that every conjugacy between two shifts of finite type can be broken down into a finite sequence of splittings and amalgamations of their edge graphs. When dealing with two-dimensional shifts of finite type, the appropriate edge graph description is not as clear; we turn to Nasu's notion of a "textile system" for such a description and show that all two-dimensional shifts of finite type can be so described. We then define textile splittings and amalgamations and prove …

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The I-Band Tully-Fisher Relation For Sc Galaxies: 21 Centimeter H I Line Data, Martha P. Haynes, Riccardo Giovanelli, Pierre Chamaraux, Luiz N. Da Costa, Wolfram Freudling, John J. Salzer, Gary Wegner May 1999

The I-Band Tully-Fisher Relation For Sc Galaxies: 21 Centimeter H I Line Data, Martha P. Haynes, Riccardo Giovanelli, Pierre Chamaraux, Luiz N. Da Costa, Wolfram Freudling, John J. Salzer, Gary Wegner

Dartmouth Scholarship

A compilation of 21 cm line spectral parameters specifically designed for application of the Tully-Fisher (TF) distance method is presented for 1201 spiral galaxies, primarily field Sc galaxies, for which optical I-band photometric imaging is also available. New H I line spectra have been obtained for 881 galaxies. For an additional 320 galaxies, spectra available in a digital archive have been reexamined to allow application of a single algorithm for the derivation of the TF velocity width parameter. A velocity width algorithm is used that provides a robust measurement of rotational velocity and permits an estimate of the error …

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Economic Markets As A Means Of Open Mobile-Agent Systems, Jonathan Bredin, David Kotz, Daniela Rus May 1999

Economic Markets As A Means Of Open Mobile-Agent Systems, Jonathan Bredin, David Kotz, Daniela Rus

Dartmouth Scholarship

Mobile-agent systems have gained popularity in use because they ease the application design process by giving software engineers greater flexibility. Although the value of any network is dependent on both the number of users and the number of sites participating in the network, there is little motivation for systems to donate resources to arbitrary agents. We propose to remedy the problem by imposing an economic market on mobile-agent systems where agents purchase resources from host sites and sell services to users and other agents. Host sites accumulate revenues, which are distributed to users to be used to launch more agents. …

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Measurement Of Free Radicals Oh And Ho₂ In Los Angeles Smog, Linda Acha George, Thomas M. Hard, Robert J. O'Brien May 1999

Measurement Of Free Radicals Oh And Ho₂ In Los Angeles Smog, Linda Acha George, Thomas M. Hard, Robert J. O'Brien

Environmental Science and Management Faculty Publications and Presentations

Atmospheric free radicals hydroxyl and hydroperoxyl (OH and HO₂, collectively HOᵪ ) are the catalysts that cause secondary or photochemical air pollution. Chemical mechanisms for oxidant and acid formation, on which expensive air pollution control strategies are based, must accurately predict these radical concentrations. We have used the fluorescence assay with gas expansion (FAGE) technique to carry out the first simultaneous, in situ measurements of these two radicals in highly polluted air during the Los Angeles Free Radical Experiment. A complete suite of ancillary measurements was also made, including speciated hydrocarbons, carbon monoxide, aldehydes, nitric oxide, nitrogen dioxide, and ozone …

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Mobile Code: The Future Of The Internet, David Kotz, Robert S. Gray May 1999

Mobile Code: The Future Of The Internet, David Kotz, Robert S. Gray

Dartmouth Scholarship

Use of the Internet has exploded in recent years with the appearance of the World-Wide Web. In this paper, we show how current technological trends necessarily lead to a system based substantially on mobile code, and in many cases, mobile agents. We discuss several technical and non-technical hurdles along the path to that eventuality. Finally, we predict that, within five years, nearly all major Internet sites will be capable of hosting and willing to host some form of mobile agents.

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Asymptotic Behavior Of The Height In A Digital Search Tree And The Longest Phrase Of The Lempel-Ziv Scheme, Charles Knessl, Wojciech Szpankowski May 1999

Asymptotic Behavior Of The Height In A Digital Search Tree And The Longest Phrase Of The Lempel-Ziv Scheme, Charles Knessl, Wojciech Szpankowski

Department of Computer Science Technical Reports

No abstract provided.

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An Agent-Based Design For Problem Solving Environments, Dan C. Marinescu May 1999

An Agent-Based Design For Problem Solving Environments, Dan C. Marinescu

Department of Computer Science Technical Reports

No abstract provided.

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Parallel Algorithms For Large Sparse Generalized Elgin Problems (Ph.D. Thesis), Zhanye Tong May 1999

Parallel Algorithms For Large Sparse Generalized Elgin Problems (Ph.D. Thesis), Zhanye Tong

Department of Computer Science Technical Reports

No abstract provided.

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Biological Metaphors In He Design Of Complex Software Systems, Dan C. Marinescu, Ladislau Bölöni May 1999

Biological Metaphors In He Design Of Complex Software Systems, Dan C. Marinescu, Ladislau Bölöni

Department of Computer Science Technical Reports

No abstract provided.

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Planarity Of Para Hexaphenyl, Suchismita Guha, Wilhelm Graupner, Roland Resel, Meera Chandrasekhar, H. R. Chandrasekhar, Rainer Glaser, Günther Leising May 1999

Planarity Of Para Hexaphenyl, Suchismita Guha, Wilhelm Graupner, Roland Resel, Meera Chandrasekhar, H. R. Chandrasekhar, Rainer Glaser, Günther Leising

Chemistry Faculty Research & Creative Works

We present experimental and theoretical findings on the geometry of polycrystalline para hexaphenyl via Raman scattering. The planarity of the molecule is affected by hydrostatic pressure and temperature. Our studies indicate that the potential energy curve which governs the torsional motion between neighboring phenyl rings is "W" shaped. We determine the activation energy to promote the molecule from a nonplanar to a planar state to be 0.04 eV, in good agreement with our quantum chemical calculations. From the relative intensities of the 1280cm-1 to the 1220cm-1 Raman modes we show that high pressure planarizes the molecules, modifying the …

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Liquid Reaction Apparatus For Surface Analysis, Charles C. Chusuei, T. S. Murrell, J. S. Corneille, M. G. Nooney, S. M. Vesecky, L. R. Hossner, D. W. Goodman May 1999

Liquid Reaction Apparatus For Surface Analysis, Charles C. Chusuei, T. S. Murrell, J. S. Corneille, M. G. Nooney, S. M. Vesecky, L. R. Hossner, D. W. Goodman

Chemistry Faculty Research & Creative Works

A design for a liquid reaction apparatus is described which allows surfaces prepared in ultrahigh vacuum (UHV) to be reacted with solutions of a wide pH range under dry nitrogen atmosphere and subsequently returned to UHV for surface analysis.

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Evaluating Snowmelt Runoff, Infiltration, And Erosion In A Sagebrush-Steppe Ecosystem, Eric K. Duffin May 1999

Evaluating Snowmelt Runoff, Infiltration, And Erosion In A Sagebrush-Steppe Ecosystem, Eric K. Duffin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Production of low-level radioactive waste (LLRW) has created a need for safe storage facilities. These facilities must be capable of isolating radioactive waste and preventing contamination from physical or biological intrusion until the waste material is isotopically stable. At the present time, managers of the Idaho National Engineering and Environmental Laboratory (INEEL) have a substantial database characterizing rainfall events and the subsequent impact on integrity of shallow land burial sites used for storage of LLRW. Little information has been gathered describing the processes of snow accumulation/ablation and the resulting impact on storage facilities. This study examines snowmelt runoff, infiltration, and …

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Thermodynamic And Binding Studies Of Ligand-Carcinogen Dna Targets, Qianying Liang May 1999

Thermodynamic And Binding Studies Of Ligand-Carcinogen Dna Targets, Qianying Liang

Seton Hall University Dissertations and Theses (ETDs)

No abstract provided.

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