Physical Sciences and Mathematics Commons^™

Migrant Threads On Process Farms: Parallel Programming With Ariadne*, Edward Mascarenhas, Vernon Rego

Department of Computer Science Technical Reports

No abstract provided.

Lightweight Write Detection And Checkpointing For Fine-Grained Persistence, Antony L. Hosking, J. Eliot B. Moss

Department of Computer Science Technical Reports

No abstract provided.

The New Jersey Machine-Code Toolkit, Norman Ramsey, Mary F. Fernáyesndez

Department of Computer Science Technical Reports

No abstract provided.

Sliced Configuration Spaces For Curved Planar Bodies, Elisha Sacks, Chandrajit Bajaj

Department of Computer Science Technical Reports

No abstract provided.

Kenematic Tolerance Analysis, Leo Joskowicz, Elisha Sacks, Vijay Srinivasan

Department of Computer Science Technical Reports

No abstract provided.

Partitioned Data Management In Mobile Environments, Ahmed K. Elmagarmid, Jin Jing, Abdelsalam Helal, Rafael Alonso

Department of Computer Science Technical Reports

No abstract provided.

Pattern Matching Image Compression: Algorithmic And Empirical Results, Mikhail J. Atallah, Yann Génin, Wojciech Szpankowski

Department of Computer Science Technical Reports

No abstract provided.

Dispersal Dynamics In A Wind-Driven Benthic System, John A. Commito, S. F. Thrush, R. D. Pridmore, J. E. Hewitt, V. J. Cummings

Environmental Studies Faculty Publications

Bedload and water column traps were used with simultaneous wind and water velocity measurements to study postlarval macrofaunal dispersal dynamics in Manukau Harbour, New Zealand. A 12-fold range in mean wind condition resulted in large differences in water flow (12-fold), sediment flux (285-fold), and trap collection of total number of individuals (95-fold), number of the dominant infaunal organism (84-fold for the bivalve Macomona liliana), and number of species (4-fold). There were very strong, positive relationships among wind condition, water velocity, sediment flux, and postlarval dispersal, especially in the bedload. Local density in the ambient sediment was not a good predictor …

Methods For Generating Quasi-Exactly Solvable Potentials, Asim Gangopadhyaya, Avinash Khare, Uday P. Sukhatme

Physics: Faculty Publications and Other Works

We describe three different methods for generating quasi-exactly solvable potentials, for which a finite number of eigenstates are analytically known. The three methods are respectively based on (i) a polynomial ansatz for wave functions; (ii) point canonical transformations; (iii) supersymmetric quantum mechanics. The methods are rather general and give considerably richer results than those available in the current literature.

Local Magnetic Properties Of Antiferromagnetic Febr2, J. Pelloth, R.A. Brand, S. Takele, M.M. Pereira De Azevedo, Wolfman Kleemann, Christian Binek, J. Kushauer, D. Bertrand

Christian Binek Publications

The antiferromagnet FeBr₂ has been studied by Mössbauer spectroscopy in external fields both in the metamagnetic region below the multicritical temperature T_MCP and in the second-order transition region above. The local magnetization shows that the metamagnetic transition occurs by spin flips, as in simple models. However, in the second-order transition region, the local magnetization of the sublattice oriented antiparallel to the external field varies continuously but remains parallel to the c axis. This can only be understood if the external magnetic field induces strong transversal spin precession of the moments on the antiparallel sublattice. This shows that the …

Simulation Modeling Within Workflow Technology, John A. Miller, Amit P. Sheth, Krzysztof J. Kochut, Xuzhong Wang, Arun Murugan

Kno.e.sis Publications

This paper presents an approach for integrating simulation modeling and analysis capabilities within the workflow management system (WFMS) being developed in the Large Scale Distributed Information Systems (LSDIS) Lab at the University of Georgia. Simulation modeling can be used for studying the efficiency of workflow designs as well as studying the general performance and reliability of WFMSs. We also discuss the importance of using sophisticated monitoring and animation capabilities, and the use of workflow management technology to advance simulation technology itself. Finally, we demonstrate a sample simulation where tasks and task managers are simulated.

Damariscotta River Estuary: A Management Plan, Fran Rudoff, Jenny Ruffing, Tom Ford

Documents from Environmental Organizations

One purpose ofthe Damariscotta River Estuary Project has been to ask and answer these and other questions. A second and equally important purpose ofthe Project has been to help the seven estuary communities improve communication and the ability to coordinate land and water use decisions to ensure the future good health of the estuary’s resources.

Failure Of The Optical Theorem For Gaussian-Beam Scattering By A Spherical Particle, James A. Lock, Joseph T. Hodges, Gérard Gouesbet

Physics Faculty Publications

It is shown that when an electromagnetic wave with some degree of amplitude rolloff in the transverse direction is scattered by a spherical particle, the optical theorem is not valid. For such shaped beams the extinction cross section may be written as an infinite series in powers of the reciprocal of the beam width. The imaginary part of the forward-scattering amplitude is shown to be the first term in this series. Two approximations to based on the dominance of diffraction in the forward direction for w(0) greater than or similar to a, where w(0) is the beam half-width and a …

The Prairie Naturalist Volume 27, No.4 December 1995

The Prairie Naturalist

NEW DISTRIBUTIONAL RECORDS FOR MAMMALS IN KANSAS · D. W Sparks and J. R. Choate

CLAY-COLORED SPARROWS IN NORTH DAKOTA PARASITIZED BY BROWN-HEADED COWBIRDS ▪ G. P. Romig and R. D. Crawford

A NOTEWORTHY RECORD AND THE BREEDING DISTRIBUTION OF THE BLUE GROSBEAK IN NORTH DAKOTA ▪ L. D. Igl

NEAR LONGEVITY RECORD FOR THE SNOW GOOSE ▪ M T. Koenen and D. M. Leslie, Jr.

COMPARISON OF WATER CONSUMPTION BETWEEN TWO GRASSLAND EMBERIZIDS ▪ J. L. Zimmerman

FACTORS ASSOCIATED WITH DECLINING PROPORTION OF CITIZENS HUNTING IN SOUTH DAKOTA ▪ N. J. Dietz, K. F. Higgins, and R. D. Mendelsohn …

Investigation Of Isolated Sand Shoals On The Inner Shelf Of Virginia Relative To The Potential For Aggregate Mining : Report On Task 4, Possible Physical Impact Of Dredging At Sandbridge Shoal Of The 1993-1995 U. S. Minerals Management Service - Commonwealth Of Virginia Cooperative Project, Jerome P.-Y. Maa

Reports

The Virginia Institute of Marine Science, together with other state agencies, has a continuing interest in preserving the coastline of Virginia, particularly, the Atlantic coastline in the vicinity of the resort city of Virginia Beach. Because a well maintained beach can serve several purposes, e.g., (1) providing public recreational areas, (2) protecting valuable properties that are located near coastline, and (3) reducing the rate of land loss, a great deal of efforts has been devoted to understand the processes that affect the change of shoreline. Among several erosion forces, waves are especially important elements as they can alter the shoreline …

Transitions Between Convective Patterns In Chemical Fronts, Y. Wu, D. A. Vasquez, Boyd F. Edwards, J. W. Wilder

All Physics Faculty Publications

We present a theory for the transition from nonaxisymmetric to axisymmetric convection in iodate-arsenous acid reaction fronts propagating in a vertical slab. The transition takes place away from the onset of convection, where a convectionless flat front becomes unstable to a nonaxisymmetric convective front. The transition is studied by numerically solving a reaction-diffusion equation coupled with nonlinear hydrodynamics in a two-dimensional slab.

Upper-Tropospheric Aerosol Sampled During Project Fire Ifo Ii, Donald E. Hagen, Josef Podzimek, Max B. Trueblood

Physics Faculty Research & Creative Works

Aerosols can play a role in the cloud formation process through the heterogeneous nucleation mechanism, and in turn, once formed, cirrus clouds can impact the ambient aerosol through scavenging and other collection mechanisms. University of Missouri aerosol sampling facilities were employed on aircraft for in situ collection and characterization of the particulates near cirrus cloud level. Tandem differential mobility analyzer and impactor techniques were used to measure aerosol size distribution, hydration capability, and particle composition information. Evidence of aerosol layering was observed near the tropospause, and there was a tendency toward depletion of the ambient aerosol at both ends of …

Single Molecule Emission Characteristics In Near-Field Microscopy, Randy X. Bian, Robert C. Dunn, X. Sunney Xie, P.T. Leung

Physics Faculty Publications and Presentations

In near-field scanning optical microscopy (NSOM), the measured fluorescence lifetime of a single dye molecule can be shortened or lengthened, sensitively dependent on the relative position between the molecule and aluminum coated fiber tip. The modified lifetimes and other emission characteristics are simulated by solving Maxwell equations with the finite-difference time-domain (FDTD) method. The 2D computation reveals insight into the lifetime behaviors and provides guidance for nonperturbative spectroscopic measurements with NSOM. This new methodology is capable of predicting molecular emission properties in front of a metal/dielectric interface of arbitrary geometry.

Packet Routing In Networks With Long Wires, Ronald I. Greenberg, Hyeong-Cheol Oh

Computer Science: Faculty Publications and Other Works

In this paper, we examine the packet routing problem for networks with wires of differing length. We consider this problem in a network independent context, in which routing time is expressed in terms of "congestion" and "dilation" measures for a set of packet paths. We give, for any constant ϵ > 0, a randomized on-line algorithm for routing any set of Npackets in O((C lg^ϵ(Nd) + D lg(Nd))/lg lg(Nd)) time, where C is the maximum congestion and D is the length of the longest path, both taking wire delays into …

Observation Of Beam-Induced Changes In The Polarization Of Balmer-Α Radiation Emitted Following Beam--Tilted-Foil Transmission, Wang Qi, David D. Allred, Larry V. Knight, Douglas L. Harper, Royal G. Albridge, Norman H. Tolk

Faculty Publications

Measurements of the circular polarization of Balmer-α radiation emitted by excited hydrogen atoms, following the transmission of (20-50)-keV protons through thin, tilted amorphous carbon foils, exhibit markedly unexpected behavior as a function of exposure of the foil to the proton beam. Specifically, the circular polarization changes from an initially well understood tilt-angle dependence to a behavior which, for low tilt angles, gives the opposite handedness of circular polarization from that predicted. In addition, the degree of alignment, indicated by the linear Stokes parameter M/I, is enhanced also as a function of dose. These changes in the tilt-angle dependence of the …

Dynamics Of Binary Liquids In Pores, J.C. Lee

Faculty Publications

A computer simulation is performed to study the dynamics of binary liquids in the pores of Vycor glasses. The pores are modeled with glass walls that form randomly interconnected tunnels. When the relaxation is probed with a particular wavelength, the time autocorrelation function depends on whether or not there is a significant periodic or quasiperiodic structure in the distribution of the walls with that wavelength. If there is not, the relaxation may be fitted as the sum of an exponential term and a nonexponential activated term. If there is, the relaxation shows a long-lasting tail that can be fitted by …

Distribution Of Submerged Aquatic Vegetation In The Chesapeake Bay And Tributaries And Chincoteague Bay - 1994, R J. Orth, Judith F. Nowak, Gary F. Anderson, David J. Wilcox, Jennifer R. Whiting, Leah S. Nagy

Reports

No abstract provided.

Water!, Kirk J. Havens, Virginia Institute Of Marine Science, Wetlands Program

Reports

No abstract provided.

Adaptive Methods For Distributed Video Presentation, Crispin Cowan, Shanwei Cen, Jonathan Walpole, Carlton Pu

Computer Science Faculty Publications and Presentations

This paper describes problems and solutions for delivering real-time, multi-media presentations across the Internet. A key characteristic of presentations of continuous media datatypes, such as digital video and audio, is their need for predictable real-time data delivery. For example, an NTSC quality video presentation requires video frames to be displayed every 1/30th of a second. Variations in this display rate can be observable as stalls or glitches in the video stream and reduce the quality of the presentation [6]. Delivering such presentations across the Internet is difficult because highly variable band- width and latency make it difficult to predict the …

A Sweet Home No More?: The Future For Habitat Protection Under The Endangered Species Act, Federico Cheever, Murray D. Feldman, University Of Colorado Boulder. Natural Resources Law Center

A Sweet Home No More?: The Future for Habitat Protection Under the Endangered Species Act (November 29)

20 pages.

Includes bibliographical references and biographical information for Federico Cheever and Murray D. Feldman.

Contents:

Babbitt v. Sweet Home Chapter of Communities for a Greater Oregon / Federico Cheever -- The Sweet Home decision and private property issues / Murray D. Feldman -- Memorandum of Agreement between the State of Colorado and the Department of the Interior concerning programs to manage Colorado's declining native species

The U.S. Supreme Court decision in Babbitt v. Sweet Home Chapter of Communities for a Great Oregon,115 S.Ct. 2407 (1995), held that the Department of the Interior reasonably construed Congress' intent when it included …

Temporal Measurement And Analysis Of High-Resolution Spectral Signatures Of Plants And Relationships To Biophysical Characteristics, Charles R. Bostater, Jan Rebbman, Carlton Hall, Mark Provancha, David Vieglais

Ocean Engineering and Marine Sciences Faculty Publications

Measurements of temporal reflectance signatures as a function of growing season for sand live oak (Quercus geminata), myrtle oak (Q. myrtifolia) and saw palmetto (Serenoa repens) were collected during a two year study period. Canopy level spectral reflectance signatures, as a function of 252 channels between 368 and 1 1 15 nm, were collected using near nadir viewing geometry and a consistent sun illumination angle. Leaf level reflectance measurements were made in the laboratory using a halogen light source and an environmental optics chamber with a barium sulfate reflectance coating. Spectral measurements were related to several biophysical measurements utilizing optimal …

Forming B1-XCX Semiconductor Devices By Chemical Vapor Deposition, Peter A. Dowben

Peter Dowben Publications

Active semiconductor devices including heterojunction diodes and thin film transistors are formed by PECVD deposition of a boron carbide thin film on an N-type substrate. The boron to carbon ratio of the deposited material is controlled so that the film has a suitable band gap energy. Boron carbides such as B_4.7C, B_7.2C and B₁₉C have suitable band gap energies between 0.8 and 1.7 eV. The stoichiometry of the film can be selected by varying the partial pressure of precursor gases, such as nido pentaborane and methane. The precursor gas or gases are energized, e.g., …

A 2-2/3 Approximation For The Shortest Superstring Problem, Chris Armen, Clifford Stein

Computer Science Technical Reports

Given a collection of strings S={s_1, ..., s_n} over an alphabet \Sigma, a superstring \alpha of S is a string containing each s_i as a substring; that is, for each i, 1<=i<=n, \alpha contains a block of |s_i| consecutive characters that match s_i exactly. The shortest superstring problem is the problem of finding a superstring \alpha of minimum length. The shortest superstring problem has applications in both data compression and computational biology. In data compression, the problem is a part of a general model of string compression proposed by Gallant, Maier and Storer (JCSS '80). Much of the recent interest in the problem is due to its application to DNA sequence assembly. The problem has been shown to be NP-hard; in fact, it was shown by Blum et al.(JACM '94) to be MAX SNP-hard. The first O(1)-approximation was also due to Blum et al., who gave an algorithm that always returns a superstring no more than 3 times the length of an optimal solution. Several researchers have published results that improve on the approximation ratio; of these, the best previous result is our algorithm ShortString, which achieves a 2 3/4-approximation (WADS '95). We present our new algorithm, G-ShortString, which achieves a ratio of 2 2/3. It generalizes the ShortString algorithm, but the analysis differs substantially from that of ShortString. Our previous work identified classes of strings that have a nested periodic structure, and which must be present in the worst case for our algorithms. We introduced machinery to descibe these strings and proved strong structural properties about them. In this paper we extend this study to strings that exhibit a more relaxed form of the same structure, and we use this understanding to obtain our improved result.

The Lyman Continuum In Starburst Galaxies Observed With The Hopkins Ultraviolet Telescope, Claus Leitherer, Henry C. Ferguson, Timothy M. Heckman, James D. Lowenthal

Astronomy: Faculty Publications

The starburst galaxies IRAS 08339+6517, Mrk 1267, Mrk 66, and Mrk 496 (=NGC 6090) were observed with the Hopkins Ultraviolet Telescope (HUT) during the Astro-2 mission. All four galaxies have radial velocities larger than 5000 km s-1, permitting the measurement of their intrinsic Lyman continuum fluxes redward of the H I absorption edge in our Galaxy. The sample was selected on the basis of having the most favorable conditions for the escape of Lyman continuum photons. Two a upper limits of Fk < 7 X 10-16 ergs s-1 cm-2 A-1 were obtained for the flux around 900 A within the rest frame of each galaxy.A set of theoretical spectral energy distributions has been calculated. We show that there exists a tight correlation between the continuum luminosity at 900 A and the total number of photons emitted in the Lyman continuum, which is valid for high- and low-metallicity galaxies and essentially all relevant initial mass functions and star formation histories. Comparison with the observed values suggests that, on average, less than 3% of the intrinsic Lyman continuum photons escape from the program galaxies. Models for the ionization of the intergalactic medium at high 2 by young starbursts require a significant fraction of the ionizing radiation to escape from the galaxy. If the four galaxies observed by us have properties similar to young galaxies at redshift 2 2 3, such galaxies are not likely to provide Lyman continuum photons for the ionization of the early universe.

Information Retrieval, Information Structure, And Information Agents, Daniela Rus, Devika Subramanian

Computer Science Technical Reports

This paper presents a customizable architecture for software agents that capture and access information in large, heterogeneous, distributed electronic repositories. The key idea is to exploit underlying structure at various levels of granularity to build high-level indices with task-specific interpretations. Information agents construct such indices and are configured as a network of reusable modules called structure detectors and segmenters. We illustrate our architecture with the design and implementation of smart information filters in two contexts: retrieving stock market data from Internet newsgroups, and retrieving technical reports from Internet ftp sites.