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1999

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Articles 601 - 630 of 2348

Full-Text Articles in Physical Sciences and Mathematics

A Family Of Hierarchical Encoding Techniques For Image And Video Communications, Samah A. Senbel Jul 1999

A Family Of Hierarchical Encoding Techniques For Image And Video Communications, Samah A. Senbel

Computer Science Theses & Dissertations

As the demand for image and video transmission and interactive multimedia applications continues to grow, scalable image and video compression that has robust behavior over unreliable channels are of increasing interest. These desktop applications require scalability as a main feature due to its heterogeneous nature, since participants in an interactive multimedia application have different needs and processing power. Also, the encoding and decoding algorithm complexity must be low due to the practical considerations of low-cost low-power receiver terminals. This requires image and video encoding techniques that jointly considers compression, scalability, robustness, and simplicity.

In this dissertation, we present a family …


Development And Application Of Adaptive Dynamic Grids For Wake Vortex/Ground Interaction, Ilker Emin Türkgeldi Jul 1999

Development And Application Of Adaptive Dynamic Grids For Wake Vortex/Ground Interaction, Ilker Emin Türkgeldi

Mechanical & Aerospace Engineering Theses & Dissertations

An adaptive and dynamic grid approach is developed for the numerical computations of wake vortex flow problems with ground interaction. The unnecessary grid points at the far field of the original, large, single zone grid are removed for computational efficiency. Next, the grid is modified into an adaptive one, where the fine core region keeps track of the vortices and can be split into two regions when the vortex separation distance exceeds a specified limit length. In the final step a multi zonal feature is added to this grid by means of two embedded grids placed at the vortex centers …


Newton Parameter Update Algorithm For Recurrent Neural Networks Applied To Adaptive System Identification And Control, Donald Allen Gates Jul 1999

Newton Parameter Update Algorithm For Recurrent Neural Networks Applied To Adaptive System Identification And Control, Donald Allen Gates

Electrical & Computer Engineering Theses & Dissertations

This paper shows that the combination of a second-order neural network parameter update algorithm and internal network feedback can be effectively used for adaptive, nonlinear, dynamical system identification and control. Adaptive neural identification and control algorithms are typically utilized for real-time applications where the rate of adaptation is often critical. A fast, adaptive network parameter update algorithm is presented.

Simulation results show that this algorithm is capable of quickly identifying and adapting to changes in system parameters, making it feasible to use for real-time control and fault accommodation applications.


Resource Partitioning Between Coyotes And Swift Foxes: Space, Time, And Diet, Ann M. Kitchen, Eric M. Gese, Edward R. Schauster Jul 1999

Resource Partitioning Between Coyotes And Swift Foxes: Space, Time, And Diet, Ann M. Kitchen, Eric M. Gese, Edward R. Schauster

United States Department of Agriculture Wildlife Services: Staff Publications

In its current distribution and abundance, the swift fox (Vulpes velox) has been significantly reduced from its historic range. A possible cause is competition with, and predation by, coyotes (Canis latrans). We investigated the level of spatial, temporal, and dietary resource use overlap between swift foxes and coyotes at the Pinon Canyon Maneuver Site in southeastern Colorado. We captured and radio-tracked 73 foxes and 24 coyotes from April 1997 to August 1998. We collected 10 832 and 5350 locations of foxes and coyotes, respectively. Overall, home-range sizes of foxes and coyotes were 7.6 ± 0.5 (mean ± SE) …


Unoccupied Band Structure Of Strained Gadolinium, Takashi Komesu, C. Waldfried, Peter A. Dowben Jul 1999

Unoccupied Band Structure Of Strained Gadolinium, Takashi Komesu, C. Waldfried, Peter A. Dowben

Peter Dowben Publications

From spin-polarized inverse photoemission, the experimental spin-resolved unoccupied band structure of gadolinium on Mo(112) has been constructed. The spin-dependent unoccupied electronic structure near the Fermi level is dominated by shallow dispersion of a spin-minority band. A spin-majority and -minority bulk-band pair also exhibits some dispersion across the Brillouin zone.


Unoccupied Band Structure Of Strained Gadolinium, Takashi Komesu, C. Waldfried, Peter A. Dowben Jul 1999

Unoccupied Band Structure Of Strained Gadolinium, Takashi Komesu, C. Waldfried, Peter A. Dowben

Peter Dowben Publications

From spin-polarized inverse photoemission, the experimental spin-resolved unoccupied band structure of gadolinium on Mo(112) has been constructed. The spin-dependent unoccupied electronic structure near the Fermi level is dominated by shallow dispersion of a spin-minority band. A spin-majority and -minority bulk-band pair also exhibits some dispersion across the Brillouin zone.


Structure And Hysteresis Of Patterned Soft-Magnetic Structure, C. N. Borca, Ralph Skomski, Peter A. Dowben Jul 1999

Structure And Hysteresis Of Patterned Soft-Magnetic Structure, C. N. Borca, Ralph Skomski, Peter A. Dowben

Peter Dowben Publications

We have analyzed the magnetism of Ni features deposited on nonmagnetic substrates using a novel method: laser assisted chemical vapor deposition. Both coercivity and loop shape are determined on a scale of order 1 mm, which is much smaller than the lateral size of the features. The magnetization curves are fitted to a simple substructure morphology model, although there is secondary dependence of the coercivity on the shape of the structures.


Interannual Variations In Snowmelt Onset And Links To 500 Hpa Atmospheric Anomalies Over The Arctic, Sheldon D. Drobot, Mark R. Anderson Jul 1999

Interannual Variations In Snowmelt Onset And Links To 500 Hpa Atmospheric Anomalies Over The Arctic, Sheldon D. Drobot, Mark R. Anderson

Department of Earth and Atmospheric Sciences: Faculty Publications

Interannual variations in the melt onset of snow provide a mechanism to observe climatic fluctuations. Timing of initial ablation is associated with certain poorly defined overlying atmospheric conditions. This paper investigates the spatial and temporal patterns in melt onset dates and associated 500 hPa height anomalies over the Arctic region from 1982 to 1992. Melt onset dates are derived from Scanning Multichannel Microwave Radiometer (SMMR) and Special Sensor Microwave Imager (SSM/I) data, while 500 hPa height anomalies are computed from the National Centers for Environmental Protection (NCEP) reanalysis models. Results indicate significant interannual variations in the spatial pattern and timing …


Nickelocene Adsorption On Single-Crystal Surfaces, D. L. Pugmire, C. M. Woodbridge, S. Root, Marjorie Langell Jul 1999

Nickelocene Adsorption On Single-Crystal Surfaces, D. L. Pugmire, C. M. Woodbridge, S. Root, Marjorie Langell

Marjorie A. Langell Publications

Nickelocene adsorption onto Ag(100), Ni(100), and NiO(100)/Ni(100) surfaces was studied with x-ray photoelectron spectroscopy and high-resolution electron energy loss spectroscopy at 135 K for monolayer and multilayer coverages of NiCp2. On the relatively inert Ag(100) surface, nickelocene physisorbs molecularly, with its molecular axis perpendicular to the surface plane. Exposure to the reactive Ni(100) surface results in the decomposition of nickelocene into acetylene and acetylene-like fragments and, when this surface is warmed to 273 K, carbide contamination is observed. There is evidence for double-bond carbon on nickelocene-exposed NiO(100), and vinyl and propenyl fragments are the most likely decomposition products …


Nitrate Reductase Activity, Nitrate Uptake And Iodine Speciation In The Marine Environment, Chin-Chang Hung Jul 1999

Nitrate Reductase Activity, Nitrate Uptake And Iodine Speciation In The Marine Environment, Chin-Chang Hung

OES Theses and Dissertations

The present method for the determination of new production (NP) by measuring the uptake of added 15NO3– suffers from a number of limitations. In an attempt to improve this situation, this research examined the possibility of estimating 15NO3– uptake by measuring the activity of nitrate reductase (NRA). In addition, because it has long been suspected that the biological reduction of IO3– to I– may be mediated by nitrate reductase (NR), this research investigated the ability of NR to catalyze the reduction of iodate to iodide.

An improved method for the determination …


Black Bear Damage To Forest Stands In Western Washington, William B. Stewart, Gary W. Witmer, Gary M. Koehler Jul 1999

Black Bear Damage To Forest Stands In Western Washington, William B. Stewart, Gary W. Witmer, Gary M. Koehler

United States Department of Agriculture Wildlife Services: Staff Publications

Cambium-feeding behavior by black bears (Ursus americanus), or bear damage, is a major reforestation problem in the Pacific Northwest. Historically, studies have measured the cumulative effects of damage over time, but few have viewed damage in the frame of one season. Bear damage occurring in 1996 was surveyed in areas of radio-marked bears in western Washington. Fresh damage occurred on 48% of bear location plots (n = 96). Douglas-fir (Pseudotsuga menziesii) (69%), western hemlock (Tsuga heterophylla) (19%), and Pacific silverfir (Abies amabilis) (10%) with a mean dbh of 25.1, 29.5, and 30.7cm, …


A Comparison Of Eclectic Learning And Stagger, J. Cory Barker, Jargalsaihan Batsaihan Jul 1999

A Comparison Of Eclectic Learning And Stagger, J. Cory Barker, Jargalsaihan Batsaihan

Faculty Publications

This project compares two machine-learning methods, Stagger and Eclectic on their classification correctness. Both systems were tested with real-world data sets previously used and tested in other machine learning and statistical literature. The Eclectic System performed better than Stagger on every data set.


Spectral Indications Of Unexpected Contributors To Atmospheric Co2 Variability?, Gary B. Hughes, Robert Gigengack, Haralambos N. Kritikos Jun 1999

Spectral Indications Of Unexpected Contributors To Atmospheric Co2 Variability?, Gary B. Hughes, Robert Gigengack, Haralambos N. Kritikos

Statistics

The frequency spectrum of Northern Hemisphere atmospheric CO2 concentration shows strong periodicities at 6.2, 1.0 and 0.5 years. The 6.2 year cyclicity has been attributed to non-linear interactions between the annual cycle and the atmospheric pole tide. The yearly signal is linked to terrestrial photosynthesis; phase analysis shows that annual CO2 minima occur at a lag of approximately 85 days from insolation maxima. Variations in the nominal yearly period occur during times of anomalous anthropogenic CO2 production. Periodicity at 6 months represents a deviation of the yearly signal from an annual sinusoid. If the yearly signal is …


Rare, Imperiled, And Recently Extinct Or Extirpated Mollusks Of Utah: A Literature Review, George V. Oliver, William R. Bosworth, Iii, State Of Utah Department Of Natural Resources Jun 1999

Rare, Imperiled, And Recently Extinct Or Extirpated Mollusks Of Utah: A Literature Review, George V. Oliver, William R. Bosworth, Iii, State Of Utah Department Of Natural Resources

All U.S. Government Documents (Utah Regional Depository)

About 139 species of mollusks are known to occur, or within historical times to have occurred, in Utah. The number of known Utah mollusks is not fixed and can be expected to continue to change, increasing as new molluscan discoveries are made in Utah and possibly decreasing as taxonomic revisions change our concept of how many valid mollusk species exist. This report represents one of the end products of a review of literature—published journal articles and books as well as unpublished agency reports—dealing with mollusks in Utah. The goals of this review were to determine (1) which species have been …


Molecular Techniques Reveal Wide Phyletic Diversity Of Heterotrophic Microbes Associated With Discodermia Spp. (Porifera: Demospongiae), Jose V. Lopez, Peter J. Mccarthy, Kathleen E. Janda, Robin Willoughby, Shirley A. Pomponi Jun 1999

Molecular Techniques Reveal Wide Phyletic Diversity Of Heterotrophic Microbes Associated With Discodermia Spp. (Porifera: Demospongiae), Jose V. Lopez, Peter J. Mccarthy, Kathleen E. Janda, Robin Willoughby, Shirley A. Pomponi

Marine & Environmental Sciences Faculty Articles

Sponges are well known to harbor large numbers of heterotrophic microbes within their mesohyl. Studies to determine the diversity of these associated microbes have been attempted for only a few shallow water species. We cultured various microorganisms from several species of Discodermia collected from deep water using the 'Johnson-Sea-Link' manned submersibles, and characterised them by standard microbiological identification methods. Characterisation of a small proportion (ca. 10%) of the total and potential eubacterial isolate collection with molecular systematics techniques revealed a wide diversity of microbes. Phylogenetic analyses of 32 small subunit (SSU) 16S-like rRNA gene sequences from different micorbes indicated high …


State Of The Fisheries Report 1998/1999, Jim W. Penn Jun 1999

State Of The Fisheries Report 1998/1999, Jim W. Penn

Status Reports of the Fisheries and Aquatic Resources

The State of the Fisheries document is designed as an essential supplement to the Annual Report to Parliament and provides a more detailed level of information to support the agency's non-financial performance measures. By summarising management changes, compliance activities and research data such as landings, effort, catch rates, stock assessment and breeding stock levels, this document provides a valuable reference point for Western Australian fisheries ofmajor importance to the commercial, recreational and aquaculture sectors. Information relevant to Fisheries WA's Fish and Fish Habitat Protection Program and activities undertaken on behalf ofthe Commonwealth is also provided. The report indicates that overall …


Synthesis And Characterization Of Isoregic Chiral Smectic Polyesters, Rolfe G. Petschek Jun 1999

Synthesis And Characterization Of Isoregic Chiral Smectic Polyesters, Rolfe G. Petschek

Faculty Scholarship

We prepared a series of isoregic chiral smectic polyesters based on (R)−(−)-4‘-{ω-[2-(p-hydroxy-o-nitrophenyloxy)-1-propoxy]-1-alkyloxy}-4-biphenylcarboxylic acid. The head-to-tail (p-hydroxybenzoic acid) type monomers enable us to proceed the isoregically controlled polycondensation. All the monomers exhibited the chiral smectic C and nematic mesophases. The isoregic chiral smectic polyesters have good thermal stability and exhibit monolayered chiral smectic C and smectic A structures.


Existence Theorems For Scheduling To Meet Two Objectives, April M. Rasala Jun 1999

Existence Theorems For Scheduling To Meet Two Objectives, April M. Rasala

Dartmouth College Undergraduate Theses

We will look at the existence of schedules which are simultaneously near-optimal for two criteria. First, we will present some techniques for proving existence theorems, in a very general setting, for bicriterion scheduling problems. We will then use these techniques to prove existence theorems for a large class of problems. We will consider the relationship between objective functions based on completion time, flow time, lateness and the number of on-time jobs. We will also present negative results first for the problem of simultaneously minimizing the maximum flow time and average weighted flow time and second for minimizing the maximum flow …


Resolutions Of Subsets Of Finite Sets Of Points In Projective Space, Steven P. Diaz, Anthony V. Geramita, Juan C. Migliore Jun 1999

Resolutions Of Subsets Of Finite Sets Of Points In Projective Space, Steven P. Diaz, Anthony V. Geramita, Juan C. Migliore

Mathematics - All Scholarship

Given a finite set, X, of points in projective space for which the Hilbert function is known, a standard result says that there exists a subset of this finite set whose Hilbert function is "as big as possible'' inside X. Given a finite set of points in projective space for which the minimal free resolution of its homogeneous ideal is known, what can be said about possible resolutions of ideals of subsets of this finite set? We first give a maximal rank type description of the most generic possible resolution of a subset. Then we show that this generic resolution …


The Conformal Mode In 2d Simplicial Gravity, Simon Catterall, Emil Mottola Jun 1999

The Conformal Mode In 2d Simplicial Gravity, Simon Catterall, Emil Mottola

Physics - All Scholarship

We verify that summing 2D DT geometries correctly reproduces the Polyakov action for the conformal mode, including all ghost contributions, at large volumes. The Gaussian action is reproduced even for c=10, well into the branched polymer phase, which confirms the expectation that the DT measure is indeed correct in this regime as well.


Intermediate Species Possessing Bent Dna Are Present Along The Pathway To Formation Of A Final Tbp-Tata Complex, Kay M. Parkhurst, Robyn M. Richards, Michael Brenowitz, Lawrence J. Parkhurst Jun 1999

Intermediate Species Possessing Bent Dna Are Present Along The Pathway To Formation Of A Final Tbp-Tata Complex, Kay M. Parkhurst, Robyn M. Richards, Michael Brenowitz, Lawrence J. Parkhurst

Lawrence Parkhurst Publications

Binding of the TATA-binding protein (TBP) to the “TATA” sequences present in the promoters of eukaryotic class II genes is the first step in the sequential assembly of transcription pre-initiation complexes. Myriad structural changes, including severe bending of the DNA, accompany TBP-TATA complex formation. A detailed kinetic study has been conducted to elucidate the mechanistic details of TBP binding and DNA bending. The binding of Saccharomyces cerevisiae TBP to the adenovirus major late promoter (AdMLP) was followed in real-time through a range of temperatures and TBP concentrations using fluorescence resonance energy transfer (FRET) and stopped-flow mixing. The results of association …


Zero-Parity Stabbing Information, Joseph O'Rourke, Irena Pashchenko Jun 1999

Zero-Parity Stabbing Information, Joseph O'Rourke, Irena Pashchenko

Computer Science: Faculty Publications

Everett et al. [EHN96, EHN97] introduced several varieties of stabbing information for the lines determined by pairs of vertices of a simple polygon P, and established their relationships to vertex visibility and other combinatorial data. In the same spirit, we define the “zero-parity (ZP) stabbing information” to be a natural weakening of their “weak stabbing information,” retaining only the distinction among {zero, odd, even > 0} in the number of polygon edges stabbed. Whereas the weak stabbing information’s relation to visibility remains an open problem, we completely settle the analogous questions for zero parity information, with three results: (1) ZP information …


Concentrations And Snow-Atmosphere Fluxes Of Reactive Nitrogen At Summit, Greenland, J W. Munger, D J. Jacob, S M. Fan, A S. Colman, Jack E. Dibb Jun 1999

Concentrations And Snow-Atmosphere Fluxes Of Reactive Nitrogen At Summit, Greenland, J W. Munger, D J. Jacob, S M. Fan, A S. Colman, Jack E. Dibb

Earth Sciences

Concentrations and fluxes of NOy (total reactive nitrogen), ozone concentrations and fluxes of sensible heat, water vapor, and momentum were measured from May 1 to July 20, 1995 at Summit, Greenland. Median NOy concentrations declined from 947 ppt in May to 444 ppt by July. NOy fluxes were observed into and out of the snow, but the magnitudes were usually below 1 μmol m−2 h−1 because of the low HNO3 concentration and weak turbulence over the snow surface. Some of the highest observed fluxes may be due to temporary storage by equilibrium sorption of …


High-Performance Liquid Chromatographic Separation Of Novel Atropic Α,Α-Disubstituted-Β-Amino Acids, Either On Different Β-Cyclodextrin-Bonded Phases Or As Their 1-Fluoro-2,4-Dinitrophenyl-5-L-Alanine Amide Derivatives, Gabriella Török, Antal Péter, Anne Gaucher, Michel Wakselman, Jean Paul Mazaleyrat, Daniel W. Armstrong Jun 1999

High-Performance Liquid Chromatographic Separation Of Novel Atropic Α,Α-Disubstituted-Β-Amino Acids, Either On Different Β-Cyclodextrin-Bonded Phases Or As Their 1-Fluoro-2,4-Dinitrophenyl-5-L-Alanine Amide Derivatives, Gabriella Török, Antal Péter, Anne Gaucher, Michel Wakselman, Jean Paul Mazaleyrat, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

The high-performance liquid chromatographic enantioresolution of free and N- and/or C-protected derivatives of (R, S)-2',1':1,2;1',2':3,4-dinaphthcyclohepta-1,3-diene-6-aminomethyl-6 -carboxylic acid (β2-Bin) by direct and indirect methods is reported. The direct separation was carried out on native and different derivatized β -cyclodextrin-bonded phases. The indirect resolution was achieved by applying pre-column derivatization with 1-fluoro-2,4-dinitrophenyl-5-L-alanine amide. The effects of different parameters such as the mobile phase composition and the structures of the compounds on the enantiomeric resolution are discussed.


The Stable Manifold Theorem For Stochastic Systems With Memory (Probability Seminar, Université Henri Poincaré Nancy 1), Salah-Eldin A. Mohammed Jun 1999

The Stable Manifold Theorem For Stochastic Systems With Memory (Probability Seminar, Université Henri Poincaré Nancy 1), Salah-Eldin A. Mohammed

Miscellaneous (presentations, translations, interviews, etc)

We state and prove a Local Stable Manifold Theorem for nonlinear stochastic differential systems with finite memory (viz. stochastic functional differential equations (sfde's)). We introduce the notion of hyperbolicity for stationary solutions of sfde's. We then establish the existence of smooth stable and unstable manifolds in a neighborhood of a hyperbolic stationary solution. The stable and unstable manifolds are stationary and asymptotically invariant under the stochastic semiflow. The proof uses infinite-dimensional multiplicative ergodic theory techniques and interpolation arguments.


Methylene-Only Subspectra In 13C Cpmas Using A New Double Quantum Filtering Sequence, Paola Rossi, Raju Subramanian, Gerard S. Harbison Jun 1999

Methylene-Only Subspectra In 13C Cpmas Using A New Double Quantum Filtering Sequence, Paola Rossi, Raju Subramanian, Gerard S. Harbison

Gerard S. Harbison Publications

Methodology for the assignment of 13C CPMAS spectra is still in its infancy. Previous methods of CPMAS spectral editing have utilized differences in the strength of the 13C–1H dipolar interaction or the rate and spin thermodynamics of crosspolarization from protons to carbon, to differentiate between quaternary, tertiary, and methylene carbons. We introduce a different approach, which is based on the fact that double-quantum coherence develops between the protons of a methylene group considerably faster than between most other proton spin pairs in an organic solid. We generate this coherence, filter it, convert it back to single …


Orbital Elements And Physical Parameters Of Ten Chromospherically Active Binary Stars, Francis C. Fekel, Klaus G. Strassmeier, Michael Weber, A. Washuettl Jun 1999

Orbital Elements And Physical Parameters Of Ten Chromospherically Active Binary Stars, Francis C. Fekel, Klaus G. Strassmeier, Michael Weber, A. Washuettl

Information Systems and Engineering Management Research Publications

Orbital elements have been determined for 10 chromospherically active binaries from a combination of new velocities and velocities in the literature. First orbits for three binaries, HD 33363, HD 152178, and HD 208472, are presented, as well as updated orbits for seven other binaries. Two of the latter systems, LN Peg and HD 106225 were discovered to be triple, and both short- and long-period orbits have been computed for each. Fundamental properties have been determined for the chromopherically active primary in each system.


Analysis Of N-Tier Architecture Applied To Distributed-Database Systems, Alexandre G. Valente Jun 1999

Analysis Of N-Tier Architecture Applied To Distributed-Database Systems, Alexandre G. Valente

Theses and Dissertations

N-tier architecture has been more commonly used as a methodology for developing large database applications. This work evaluates the use of this architecture instead of the classical Client/Server architecture in developing corporate applications based on distributed databases. The comparison between architectures is performed using applications that execute transactions similar to those defined in the Transaction Process Council Type C benchmark (TPC-C). The environment used for development and testing was the AFIT Bimodal Cluster (ABC); a heterogeneous cluster of PCs, running Microsoft Windows NT 4.0 OS. The comparative experimental analysis demonstrated that the N-tier architecture allows more efficient bandwidth utilization between …


Dc Field-Induced, Phase And Polarization Control Of Interference Between One- And Two-Photon Ionization Amplitudes, N. L. Manakov, V.D. Osiannikov, Anthony F. Starace Jun 1999

Dc Field-Induced, Phase And Polarization Control Of Interference Between One- And Two-Photon Ionization Amplitudes, N. L. Manakov, V.D. Osiannikov, Anthony F. Starace

Anthony F. Starace Publications

We demonstrate that a weak, static electric field enables nearly complete coherent phase control of the total ionization yield in a two-color ionization process using fundamental and second-harmonic radiation. The static electric field induces a dipole-forbidden resonance in the two-photon transition amplitude so that the final photoelectron states are identical to those in a single photon transition. We demonstrate also a phase controllable circular dichroism effect in the total photoelectron yield. Experimental realization of this process using alkali metal atoms is discussed.


Transparencies Used In The Introductory Remarks Of Doug Kenney, Ph.D., Natural Resources Law Center, Douglas Kenney Jun 1999

Transparencies Used In The Introductory Remarks Of Doug Kenney, Ph.D., Natural Resources Law Center, Douglas Kenney

Strategies in Western Water Law and Policy: Courts, Coercion and Collaboration (Summer Conference, June 8-11)

6 pages.