Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

1998

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 1111 - 1140 of 6048

Full-Text Articles in Entire DC Network

Protein Fragmentation Due To Slow Highly Charged Ion Impact, Christiane Ruehlicke, Dieter Schneider, Markus Schneider, Robert D. Dubois, Rod Balhorn Sep 1998

Protein Fragmentation Due To Slow Highly Charged Ion Impact, Christiane Ruehlicke, Dieter Schneider, Markus Schneider, Robert D. Dubois, Rod Balhorn

Physics Faculty Research & Creative Works

We present first results of experiments on the fragmentation of biomolecules using highly charged heavy ions. Fragmentation and modification of oligopeptides, such as dimerization and attachment of ionic salt components, have been observed by means of mass spectrometry. Plasmid DNA molecules were imaged with an atomic force microscope after ion irradiation and profound molecular damage was found.


A Wavelet-Based Approach To Dynamic Environments, Glenn A. Martin Sep 1998

A Wavelet-Based Approach To Dynamic Environments, Glenn A. Martin

Link Foundation Modeling, Simulation and Training Fellowship Reports

This paper demonstrates a new approach for terrain representation: multiresolution surfaces based on wavelets and the process of multiresolution analysis. Because they are based on mathematical surfaces, multiresolution surfaces gain the benefits of surfaces (more level of detail control, increased number of possible resolutions, easier updates of a dynamic terrain) that lead to fewer correlation errors both in non-networked and networked simulations. Furthermore, the power of multiple resolutions (at little added cost) reduces network transmission costs and provides a framework for the use of dynamic terrain in shared virtual worlds.


Vision-Based Tracking With Dynamic Structure Light, Mark A. Livingston Sep 1998

Vision-Based Tracking With Dynamic Structure Light, Mark A. Livingston

Link Foundation Modeling, Simulation and Training Fellowship Reports

The term virtual reality (VR) has been used in the popular press to describe systems that completely replace the user's view with computer graphics, a view of a synthetic world. Such systems allow building designers to visualize the "completed" building and potential problems in the design before construction. A VR system might allow scientists to view environments as large as galaxies or as small as atoms as if they were human-sized. The primary benefit in these cases would be to interact in more natural ways with objects that, due to their sizes, are usually beyond our reach. In academic literature, …


Software Tools For Solid Freeform Fabrication, Robert Franceschini Sep 1998

Software Tools For Solid Freeform Fabrication, Robert Franceschini

Link Foundation Modeling, Simulation and Training Fellowship Reports

A structured design methodology played a key role in the VLSI (Very Large Scale Integration) revolution. In this methodology, the design is abstracted at different levels (viz. system, function, logic, circuit, and layout) taking into account concerns relevant to a particular level of abstraction. This allows development of CAD tools that can describe, synthesize, and simulate the design at high levels of abstraction independent of the details of the lower levels. In recent years, many researchers have observed that the lessons learned from the "VLSI experience" could be profitably applied to new classes of manufacturing processes called SFF (Solid Freeform …


Imaging Derivative Spectroscopy For Vegetation Dysfunction Assessments, Charles R. Bostater Sep 1998

Imaging Derivative Spectroscopy For Vegetation Dysfunction Assessments, Charles R. Bostater

Ocean Engineering and Marine Sciences Faculty Publications

The practical application of current airborne and future satellite or space station based high spectral resolution (hyperspectral) imagery to vegetative canopies (sparse or dense) and resulting derived bio-physical variables will depend upon our ability to rapidly apply scientifically based algorithms. Key to these rapid assessments is the selection ofthe best or optimal channels or bands for detection of plant stress or dysfunction. Previous work '2,3,4,5 has demonstrated the potential of utilizing high spectral resolution optical signatures for detecting plant stress related to the vegetation's moisture within the leaf structure. Future algorithms and techniques need to discriminate plant species as well …


Specific Absorption And Backscatter Coefficient Signatures In Southeastern Atlantic Coastal Waters, Charles R. Bostater Sep 1998

Specific Absorption And Backscatter Coefficient Signatures In Southeastern Atlantic Coastal Waters, Charles R. Bostater

Ocean Engineering and Marine Sciences Faculty Publications

Measurements of natural water samples in the field and laboratory of hyperspectral signatures of total absorption and reflectance were obtained using long pathlength absorption systems (50 cm pathlength). Water was sampled in Indian River Lagoon, Banana River and Port Canaveral, Fl. Stations were also occupied in near coastal waters out to the edge ofthe Gulf Stream in the vicinity of Kennedy Space Center, Fl. and estuarine waters along Port Royal Sound and along the Beaufort River tidal area in South Carolina. The measurements were utilized to calculate natural water specific absorption, total backscatter and specific backscatter optical signatures. The resulting …


Wavelength Conversion In Wdm Networking, Byrav Ramamurthy, Biswanath Mukherjee Sep 1998

Wavelength Conversion In Wdm Networking, Byrav Ramamurthy, Biswanath Mukherjee

School of Computing: Faculty Publications

Wavelength conversion has been proposed for use in wavelength-division multiplexed networks to improve efficiency. This study highlights systems challenges and performance issues which need to be addressed in order to incorporate wavelength conversion effectively. A review/survey of the enabling technologies, design methods, and analytical models used in wavelength-convertible networks is provided.


Measurement Of The Branching Ratios For The Decays Of DS+ To Ηπ+, Η′Π+, Ηρ+, And Η′Ρ+, C. P. Jessop, Kenneth A. Bloom, Cleo Collaboration Sep 1998

Measurement Of The Branching Ratios For The Decays Of DS+ To Ηπ+, Η′Π+, Ηρ+, And Η′Ρ+, C. P. Jessop, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

Using a data sample with an integrated luminosity of 3.9 fb-1 collected in e+e- annihilation with the CLEO-II detector at the Cornell Electron Storage Ring, we have measured the branching ratios for the decay modes Ds+ → (η, η′)π+ and Ds+ → (η, η′)ρ+ relative to Ds+ → φπ+. These decay modes are among the most common hadronic decays of the Ds+, and can be related by factorization to the semileptonic decays Ds+ → (η, η′)ℓ+ν1 . …


Can Photoemission Accurately Probe The Bulk Electronic Structure Of The Complex Oxides?, Jaewu Choi, C. Waldfried, Sy-Hwang Liou, Peter A. Dowben Sep 1998

Can Photoemission Accurately Probe The Bulk Electronic Structure Of The Complex Oxides?, Jaewu Choi, C. Waldfried, Sy-Hwang Liou, Peter A. Dowben

Peter Dowben Publications

The surface of the complex oxides, in particular the manganese perovskites, is dominated by a different free enthalpy at the surface. This can be demonstrated by surface segregation after annealing the samples. By comparing relative x-ray photoelectron spectroscopy intensities of the manganese perovskite La1-xCaxMnO3 (x=0.1, 0.35) for different emission angles, the profile of elemental concentration was determined. Analysis shows evidence for pronounced surface segregation of calcium. Our results suggest that there are strong differences between surface and bulk enthalpies without segregation or surface relaxation. This is consistent with the previously observed surface resonance in the …


Radial Distribution Of Electron Spectra From High-Energy Ions, Francis A. Cucinotta, Robert Katz, John W. Wilson Sep 1998

Radial Distribution Of Electron Spectra From High-Energy Ions, Francis A. Cucinotta, Robert Katz, John W. Wilson

Robert Katz Publications

The average track model describes the response of physical and biological systems using radial dose distribution as the key physical descriptor. We report on an extension of this model to describe the average distribution of electron spectra as a function of radial distance from an ion. We present calculations of these spectra for ions of identical linear energy transfer (LET), but dissimilar charge and velocity to evaluate the differences in electron spectra from these ions. To illustrate the usefulness of the radial electron spectra for describing effects that are not described by electron dose, we consider the evaluation of the …


Higher-Order And Next-Nearest-Neighbor Néel Anisotropies , Y.T. Millev, Ralph Skomski, J. Kirschner Sep 1998

Higher-Order And Next-Nearest-Neighbor Néel Anisotropies , Y.T. Millev, Ralph Skomski, J. Kirschner

Ralph Skomski Publications

The problem of higher-order Néel anisotropies is solved by exploiting the addition theorem for spherical functions. A key advantage of the present approach is the orthonormal character of the expansion of the magnetic energy that simplifies the formalism and makes possible the treatment of nonideal morphologies as well. Explicit expressions for second-, fourth-, and sixth-order anisotropies are obtained for ideal bulk of fcc and bcc symmetry as well as for (001), (110), and (111) surfaces with nearest-neighbor (NN) Néel interactions. The systematic examination of the pair model involves partition by species of inequivalent sites, interaction spheres, and orders in the …


New Technique Detects Gas Hydrates, Walter S. Borowski, Charles K. Paull, William Ussler Iii Sep 1998

New Technique Detects Gas Hydrates, Walter S. Borowski, Charles K. Paull, William Ussler Iii

EKU Faculty and Staff Scholarship

As exploration and development moves into deep waters, the possibility of encountering gas hydrates within seafloor sediments becomes increasingly likely. The ability to accurately detect gas hydrates is key to producing deepwater fields, allowing operators to safely design and place offshore drilling and production platforms, subsea production equipment and flow lines, as well as pipelines.


Minimum Cross-Entropy Approximation For Modeling Of Highly Intertwining Data Sets At Subclass Levels, Qiuming Zhu Sep 1998

Minimum Cross-Entropy Approximation For Modeling Of Highly Intertwining Data Sets At Subclass Levels, Qiuming Zhu

Computer Science Faculty Publications

We study the problem of how to accurately model the data sets that contain a number of highly intertwining sets in terms of their spatial distributions. Applying the Minimum Cross-Entropy minimization technique, the data sets are placed into a minimum number of subclass clusters according to their high intraclass and low interclass similarities. The method leads to a derivation of the probability density functions for the data sets at the subclass levels. These functions then, in combination, serve as an approximation to the underlying functions that describe the statistical features of each data set.


Is Service Learning A Good Idea? Data From The National Longitudinal Study Of 1988., June R. Chapin Sep 1998

Is Service Learning A Good Idea? Data From The National Longitudinal Study Of 1988., June R. Chapin

Service Learning, General

Service learning is an integral part of social studies that aims to instill social responsibility among students. According to the National Longitudinal Study of 1988, a significant percentage of high school students participated in community work during the previous two years and that this involvement in community service was greatest in church or church-related groups. However, the survey showed that students favor diversity in their choice of community work and that social action is not their top priority. Furthennore, there is confusion about the difference between service and community learning.


Maintenance Of Circulation Anomalies During The 1988 Drought And 1993 Floods Over The United States, Alan Z. Liu, Mingfang Ting, Hailan Wang Sep 1998

Maintenance Of Circulation Anomalies During The 1988 Drought And 1993 Floods Over The United States, Alan Z. Liu, Mingfang Ting, Hailan Wang

Physical Sciences - Daytona Beach

The large-scale circulation anomalies associated with the 1988 drought and the 1993 floods are investigated with the National Centers for Environmental Prediction Reanalysis data and a linear stationary wave model. The transient vorticity and thermal forcings are explicitly calculated and the diabatic heating is derived as a residual in the thermodynamic energy equation. Using the April–June (AMJ) data for 1988, and June–August (JJA) data for 1993, the linear stationary wave model is able to reproduce the main features of the geopotential height anomaly for the two seasons when all forcings are included. This provides a basis for further investigation of …


Review Of The Economics Of Thomas Robert Malthus By S. Hollander, John B. Davis Sep 1998

Review Of The Economics Of Thomas Robert Malthus By S. Hollander, John B. Davis

Economics Faculty Research and Publications

No abstract provided.


An Efficient And Effective Approach To Column-Based Input/Output Encoding In Functional Decomposition, Michael Burns, Marek Perkowski, Stanislaw Grygiel, Lech Jozwiak Sep 1998

An Efficient And Effective Approach To Column-Based Input/Output Encoding In Functional Decomposition, Michael Burns, Marek Perkowski, Stanislaw Grygiel, Lech Jozwiak

Electrical and Computer Engineering Faculty Publications and Presentations

Encoding in Curtis-style decompositions is the process of assigning codes to groups of compatible columns (or cubes) so that the binary logic descriptions of the predecessor and successor sub-functions can be created for further decomposition. In doing so, the sub-functions created are functionally equivalent to the set of care values specified in the original function. In this paper an input/output encoding algorithm DC_ENC is presented that is designed to achieve the simplest total complexity of the predecessor and successor sub-functions, and to increase the total number of don't cares for their further utilization in subsequent decomposition steps of these sub-functions.


Rear Admiral Charles H. Stockton, The Naval War College, And The Law Of Naval Warfare, John Hattendorf Sep 1998

Rear Admiral Charles H. Stockton, The Naval War College, And The Law Of Naval Warfare, John Hattendorf

International Law Studies

No abstract provided.


At Issue And Book Review: Men At Work: Inspecting The Foundations Of Technology Education, Stephen Petrina Sep 1998

At Issue And Book Review: Men At Work: Inspecting The Foundations Of Technology Education, Stephen Petrina

Journal of STEM Teacher Education

No abstract provided.


Discrete-Time Continuous-Dilation Construction Of Linear Scale-Invariant Systems And Multi-Dimensional Self-Similar Signals, Wei Zhao Sep 1998

Discrete-Time Continuous-Dilation Construction Of Linear Scale-Invariant Systems And Multi-Dimensional Self-Similar Signals, Wei Zhao

Theses

This dissertation presents novel models for purely discrete-time self-similar processes and scale- invariant systems. The results developed are based on the definition of a discrete-time scaling (dilation) operation through a mapping between discrete and continuous frequencies. It is shown that it is possible to have continuous scaling factors through this operation even though the signal itself is discrete-time. Both deterministic and stochastic discrete-time self-similar signals are studied. Conditions of existence for self-similar signals are provided. Construction of discrete-time linear scale-invariant (LSI) systems and white noise driven models of self-similar stochastic processes are discussed. It is shown that unlike continuous-time self-similar …


Magma Traps And Driving Pressure: Consequences For Pluton Shape And Emplacement In An Extensional Regime, John Patrick Hogan, Jonathan D. Price, M. Charles Gilbert Sep 1998

Magma Traps And Driving Pressure: Consequences For Pluton Shape And Emplacement In An Extensional Regime, John Patrick Hogan, Jonathan D. Price, M. Charles Gilbert

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The level of emplacement and final form of felsic and mafic igneous rocks of the Wichita Mountains Igneous Province, southwestern Oklahoma, U.S.A. Are discussed in light of magma driving pressure, lithostatic load, and crustal magma traps. Deposition of voluminous A-type rhyolites upon an eroded gabbroic substrate formed a subhorizontal strength anisotropy that acted as a crustal magma trap for subsequent rising felsic and mafic magma. Intruded along this crustal magma trap are the A-type sheet granites (length/thickness 100:1) of the Wichita Granite Group, of which the Mount Scott Granite sheet is typical, and smaller plutons of biotite bearing Roosevelt Gabbro. …


Effects Of N-Acetylcysteine And 2,3-Dimercaptosuccinic Acid On Lead Induced Oxidative Stress In Rat Lenses, Rachel Neal, Katherine Cooper, Nuran Ercal, Hande Gürer-Orhan Sep 1998

Effects Of N-Acetylcysteine And 2,3-Dimercaptosuccinic Acid On Lead Induced Oxidative Stress In Rat Lenses, Rachel Neal, Katherine Cooper, Nuran Ercal, Hande Gürer-Orhan

Chemistry Faculty Research & Creative Works

Lead (Pb) is known to disrupt the pro-oxidant/anti-oxidant balance of tissues which leads to biochemical and physiological dysfunction. The present study investigated the previous termeffectsnext term of exposure on the redox status of the lenses of Fisher 344 rats and examined whether antioxidant or chelator administration reversed these changes. Animals were given 5 weeks of 2000 ppm Pb exposure followed by 1 week of either antioxidant, chelator or distilled water administration. Glutathione (GSH) and cysteine (CYS) levels decreased in the Pb-exposed group. N-previous termacetylcysteinenext term or 2,3-dimercaptopsuccinic previous termacidnext term (Succimer) supplementation following Pb intoxication resulted in increases in the …


Low-Field Hopping Among Randomly-Distributed Sites With Uncorrelated Energetic Disorder, Paul Ernest Parris Sep 1998

Low-Field Hopping Among Randomly-Distributed Sites With Uncorrelated Energetic Disorder, Paul Ernest Parris

Physics Faculty Research & Creative Works

The low-field mobility μ of a small concentration of charge carriers hopping among a random distribution of transport sites is studied, as a function of the mean interparticle spacing ρ and the temperature T, for model systems having different site-energy distribution functions. For a uniform density of states our calculations show that the mobility obeys empirical scaling laws similar to those found in the theory of variable-range hopping. For a binary distribution of site energies we observe a crossover as a function of site density between trap-limited conduction and trap-mediated conduction. For a Gaussian density of states our results confirm …


Water Balloon Rupture In Low‐G, Mark M. Weislogel, S. Lichter Sep 1998

Water Balloon Rupture In Low‐G, Mark M. Weislogel, S. Lichter

Mechanical and Materials Engineering Faculty Publications and Presentations

A qualitative study of the bursting of water balloons in a simulated low-gravity environment was conducted aboard NASA Lewis’s DC-9 aircraft.

The tests were performed to develop techniques to rapidly deploy large liquid drops in a microgravity environment.


Comparison Of The Sfi Peculiar Velocities With The Iras 1.2-Jy Gravity Field, L. N. Da Costa, A. Nusser, W. Freudling, R. Giovanelli, M. P. Haynes, J J. Salzer, G. Wegner Sep 1998

Comparison Of The Sfi Peculiar Velocities With The Iras 1.2-Jy Gravity Field, L. N. Da Costa, A. Nusser, W. Freudling, R. Giovanelli, M. P. Haynes, J J. Salzer, G. Wegner

Dartmouth Scholarship

We present a comparison between the peculiar velocity fields measured from a recently completed I-band Tully-Fisher survey of field spirals (SFI) and that derived from the IRAS 1.2-Jy redshift survey galaxy distribution. The analysis is based on the expansion of these data in redshift space using smooth orthonormal functions, and is performed using low- and high-resolution expansions, with an effective smoothing scale which increases almost linearly with redshift. The effective smoothing scales at 3000 km s−1 are 1500 and 1000 km s−1 for the low- and high-resolution filters. The agreement between the high- and low-resolution SFI velocity …


Art As A Self-Healing Process, Yu-Cheng Chuang Sep 1998

Art As A Self-Healing Process, Yu-Cheng Chuang

Theses

None provided.


Application Of Mathematical Modeling And Computer Simulation For Solving Water Quality Problems, Jacek Makinia, Scott A. Wells, David Crawford, Marian Kulbik Sep 1998

Application Of Mathematical Modeling And Computer Simulation For Solving Water Quality Problems, Jacek Makinia, Scott A. Wells, David Crawford, Marian Kulbik

Civil and Environmental Engineering Faculty Publications and Presentations

Deteriorated water resources in Central and Eastern Europe call for actions that should be undertaken to improve current conditions and to protect human and environmental health. Mathematical modeling and computer simulation is often an integral part of the decision-making process. Models and simulations allow rapid and varied evaluation of causes and effects and the principal advantage is that they enable an analysis of even long-term actions with limited investment costs. This paper provides an overview of popular models used for simulation of major elements of a water quality system: surface water quality (QUAL2E), wastewater treatment (Activated Sludge Model No.1), sewer …


A Return On Investment Model For Air Force Technology Transfer, Bradley W. Mcdonald Sep 1998

A Return On Investment Model For Air Force Technology Transfer, Bradley W. Mcdonald

Theses and Dissertations

Air Force policy states the fundamental reason for participating in technology transfer is to maximize the return on investment (ROI) on research and development (R&D) funds. Public law dictates that federal agencies, including the Air Force, are to spend no less than 0.5% of their overall R&D budget in the pursuit of technology transfer. However, there is currently no ROI model available to the decision maker in the evaluation of alternative transfer opportunities. This research effort develops a model that measures the ROI of individual cooperative research and development agreements (CIWAs) on the basis of the objective and subjective benefits …


An Exploratory Study On The Strategic Use Of Information Technology In The Source Selection Decision-Making Process, Kathy L. Spainhower Sep 1998

An Exploratory Study On The Strategic Use Of Information Technology In The Source Selection Decision-Making Process, Kathy L. Spainhower

Theses and Dissertations

The strategic use of Information Technology in the acquisition field can be very useful in the decision making process of evaluating alternative solutions during a Government source selection. Current implementation of information technology provides a more tactical approach to systems development. The use of Electronic Commerce/Electronic Data Interchange and the internet to electronically transfer information is only the beginning of the shift towards a more strategic design process for information systems within Government procurement agencies. A schematic model was designed to demonstrate how information technology, such as Decision Support Systems, Expert Systems, and Shared Data Warehousing could assist the SSA …


Portland State Magazine, Portland State University. Office Of University Communications Sep 1998

Portland State Magazine, Portland State University. Office Of University Communications

Portland State Magazine

PSU’s alumni magazine, published 2-3 times a year. In this issue: What makes seemingly good kids don ski masks and rob and terrorize a city?; a grand entrance into Portland State and south downtown is now under construction; for three alumni, finding the right job was not a daydream or a nightmare, but a real choice; in the last issue of PSU Magazine the School of Engineering was hot news. It just keeps getting better; hidden in the Columbia River Basin are stories historians are now discovering; and more.