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2001

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Articles 1561 - 1590 of 3030

Full-Text Articles in Physical Sciences and Mathematics

The Affect Of Varying Arousal Methods Upon Vigilance And Error Detection In An Automated Command And Control Environment, Brent T. Langhals Mar 2001

The Affect Of Varying Arousal Methods Upon Vigilance And Error Detection In An Automated Command And Control Environment, Brent T. Langhals

Theses and Dissertations

This study focused on improving vigilance performance through developing methods to arouse subjects to the possibility of errors in a data manipulation information warfare attack. The study suggests that by continuously applying arousal stimuli, subjects would retain initially high vigilance levels thereby avoiding the vigilance decrement phenomenon and improving error detection. The research focused on which methods were the most effective as well the impact of age upon the arousability of the subjects. Further the implications of vigilance and vigilance decrement for correct detections as well as productivity were explored. The study used a simulation experiment to provide a vigilance …

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Solving The Protein Structure Prediction Problem With Fast Messy Genetic Algorithms (Scaling The Fast Messy Genetic Algorithm To Medium-Sized Peptides By Detecting Secondary Structures), Steven R. Michaud Mar 2001

Solving The Protein Structure Prediction Problem With Fast Messy Genetic Algorithms (Scaling The Fast Messy Genetic Algorithm To Medium-Sized Peptides By Detecting Secondary Structures), Steven R. Michaud

Theses and Dissertations

The ability to accurately predict a polypeptide's molecular structure given its amino acid sequence is important to numerous scientific, medical, and engineering applications. Studies have been conducted in the application of Genetic Algorithms (GAs) to this problem with promising initial results. In this thesis report, we use the fast messy Genetic Algorithm (fmGA) to attempt to find the minimization of an empirical CHARMM energy model and generation of the associated conformation. Previous work has shown that the fmGA provided favorable results, at least when applied to the pentapeptide Met-Enkephalin. We extend these results to a larger Polyalinine peptide by utilizing …

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Software Domain Model Integration Methodology For Formal Specifications, Joel C. Nonnweiler Mar 2001

Software Domain Model Integration Methodology For Formal Specifications, Joel C. Nonnweiler

Theses and Dissertations

Using formal methods to create automatic code generation systems is one of the goals of Knowledge Based Software Engineering (KBSE) groups. The research of the Air Force Institute of Technology KBSE group has focused on the utilization of formal languages to represent domain model knowledge within this process. The code generation process centers around correctness preserving transformations that convert domain models from their analysis representations through design to the resulting implementation code. The diversity of the software systems that can be developed in this manner is limited only by the availability of suitable domain models. Therefore it should be possible …

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Influence Of Anonymity In A Group Problem-Solving Environment, Robert A. Sylvester Mar 2001

Influence Of Anonymity In A Group Problem-Solving Environment, Robert A. Sylvester

Theses and Dissertations

A group support system (GSS) uses a combination of networked personal computers, software that collects, manipulates, and aggregates member's individual input, and human facilitation to improve the group decision-making process. Prior GSS research has found that content and process anonymity influence problem solving groups. However, previous studies report mixed results on which levels of anonymity positively influence group performance. This thesis looked at content and process anonymity using four treatments to explore possible explanations for the mixed results found in previous GSS research. The study examined numerous theories including anonymity, identification, social loafing, and social comparison. An experiment was developed …

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Development Of Predictors For Cloud-To-Ground Lightning Activity Using Atmospheric Stability Indices, Kenneth C. Venzke Mar 2001

Development Of Predictors For Cloud-To-Ground Lightning Activity Using Atmospheric Stability Indices, Kenneth C. Venzke

Theses and Dissertations

A detailed examination was performed on several commonly applied atmospheric stability indices and lightning activity from 1993 to 2000 to determine the indices usefulness as predictive tools for determining cloud-to-ground lightning activity. Predetermined radii of 50 nautical miles around upper-air stations in the Midwest U.S. were used for the lightning summaries. Also explored is an improvement upon the commonly accepted thresholds of the stability indices as general thunderstorm indicators. An improvement was found and new threshold ranges were developed for relating stability index values to lightning occurrence. Traditional statistical regression methods failed to find a significant predictive relationship. By examining …

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Quantitative Validation Of A Model Of Chlorinated Ethene Natural Attenuation, Harold C. Young Mar 2001

Quantitative Validation Of A Model Of Chlorinated Ethene Natural Attenuation, Harold C. Young

Theses and Dissertations

Chlorinated ethenes are among the most prevalent groundwater contaminants at hazardous waste sites nationwide. In an attempt to manage the risks posed by these contaminants, while controlling costs, monitored natural attenuation (MNA) is being considered as a remediation strategy at many sites. MNA relies on naturally occurring physical, chemical, and biological processes in the subsurface to reduce the risk posed by the contamination. The implementation of MNA, however, requires a detailed understanding of these processes, and how they impact contamination at a particular site. One way to gain this understanding is through contaminant fate and transport modeling. In this study, …

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An Environmental Geochemical Study Of Connecticut Marsh Sediments, Nicole A. Heller, Michael A. Kruge, Johan C. Varekamp, Tabitha Zierzow Mar 2001

An Environmental Geochemical Study Of Connecticut Marsh Sediments, Nicole A. Heller, Michael A. Kruge, Johan C. Varekamp, Tabitha Zierzow

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Core material from Spartina-dominated Housatonic and Connecticut River estuarine sites (ranging from low to high marsh) were investigated in order to test the hypothesis that organic and inorganic pollutants preferentially accumulate in the low marsh environment. Radiometric data indicate that the low marsh setting experienced sedimentation rates an order of magnitude greater than that of the mid to high marsh. The low marsh sediments from the Housatonic tend to have significantly higher concentrations of trace metals (e.g., Cu and Zn, likely contributed by brass mills formerly active upstream). Petrographic examination of the samples under reflected white and blue light …

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Analyzing The Effects Of Meteorology On Radar Measured Index Of Refraction Structure Parameter, Jeffrey W. Budai Mar 2001

Analyzing The Effects Of Meteorology On Radar Measured Index Of Refraction Structure Parameter, Jeffrey W. Budai

Theses and Dissertations

Forecasting optical turbulence is essential for the Air Force's Airborne Laser program to optimize placement of aircraft. To find bow meteorology affects Cn2, the intensity of turbulence in the index of refraction, case studies of synoptically interesting times are first chosen. Correlation coefficients are then computed between radar measured Cn2 and meteorological quantities. The potential for mechanically turbulent activity is looked at. In the analysis of this work, six meteorological features were found likely to affect Cn2. Two features associated with affecting potential refractivity, and thus Cn2, are jets …

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Modeling Information Assurance, Joseph E. Beauregard Mar 2001

Modeling Information Assurance, Joseph E. Beauregard

Theses and Dissertations

The ever-increasing speed of information systems allows decision-makers around the world to gather, process, and disseminate information almost instantaneously. However, with this benefit there comes a price. Information is valuable and therefore a target to those who do not have it or wish to destroy it. The Internet has allowed information to flow freely, but it has also made information vulnerable to many forms of corruption. The U. S. military controls much of the world's most sensitive information, and since it cannot sacrifice losing the speed at which this information is currently processed and disseminated, it must find a way …

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A Flexible Framework For Collaborative Visualization Applications Using Java Spaces, Sean C. Butler Mar 2001

A Flexible Framework For Collaborative Visualization Applications Using Java Spaces, Sean C. Butler

Theses and Dissertations

The complexity of modern tasks is rising along with the level of technology. Two techniques commonly used to deal with complexity are collaboration and information visualization. Recently, computer networks have arisen as a powerful means of collaboration, and many new technologies are being developed to better utilize them. Among the newer, more promising of these technologies is Sun Microsystems' JavaSpaces ™, a high-level network programming API. This thesis describes a tool for developing collaborative visualization software using JavaSpaces-an application framework and accompanying toolkit. In addition to a detailed description of the framework, the thesis also describes an application implemented using …

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Traveling Salesman Problem For Surveillance Mission Using Particle Swarm Optimization, Barry R. Secrest Mar 2001

Traveling Salesman Problem For Surveillance Mission Using Particle Swarm Optimization, Barry R. Secrest

Theses and Dissertations

The surveillance mission requires aircraft to fly from a starting point through defended terrain to targets and return to a safe destination (usually the starting point). The process of selecting such a flight path is known as the Mission Route Planning (MRP) Problem and is a three-dimensional, multi-criteria (fuel expenditure, time required, risk taken, priority targeting, goals met, etc.) path search. Planning aircraft routes involves an elaborate search through numerous possibilities, which can severely task the resources of the system being used to compute the routes. Operational systems can take up to a day to arrive at a solution due …

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Minimum Distance Estimation For Time Series Analysis With Little Data, Hakan Tekin Mar 2001

Minimum Distance Estimation For Time Series Analysis With Little Data, Hakan Tekin

Theses and Dissertations

Minimum distance estimate is a statistical parameter estimate technique that selects model parameters that minimize a good-of-fit statistic. Minimum distance estimation has been demonstrated better standard approaches, including maximum likelihood estimators and least squares, in estimating statistical distribution parameters with very small data sets. This research applies minimum distance estimation to the task of making time series predictions with very few historical observations. In a Monte Carlo analysis, we test a variety of distance measures and report the results based on many different criteria. Our analysis tests the robustness of the approach by testing its ability to make predictions when …

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Investigation Of Gravity Waves Via The Rotational Temperature Of Hydroxyl Nightglow, Erin C. Willingham Mar 2001

Investigation Of Gravity Waves Via The Rotational Temperature Of Hydroxyl Nightglow, Erin C. Willingham

Theses and Dissertations

Measurement of the vibration and rotation bands of mesospheric hydroxyl radicals (OH) has been conducted during the past two decades using ground-based and space-based interferometers to take temperature and wind measurements from 70-100km in altitude. Gravity waves that pass through the mesosphere can be measured by determining the variance over time of the rotational temperature of the OH emissions. Several attempts were made to take spectrum measurements of the nightglow from hydroxyl radicals in the mesosphere using a custom hardware configuration that included a telescope and grating monochrometer optimized for the visible and near infrared. Quantifying gravity wave activity was …

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Non-Sequential Double Ionization Of Ne In Intense Laser Pulses: A Coincidence Experiment, Robert Moshammer, Bernold Feuerstein, Daniel Fischer, Alexander Dorn, Claus Dieter Schroter, J. Deipenwisch, Jose R. Crespo Lopez-Urrutia, C. Hohr, Paul B. Neumayer, Joachim Hermann Ullrich, Horst Rottke, Christoph Trump, M. Wittmann, Georg Korn, Wolfgang Sandner Mar 2001

Non-Sequential Double Ionization Of Ne In Intense Laser Pulses: A Coincidence Experiment, Robert Moshammer, Bernold Feuerstein, Daniel Fischer, Alexander Dorn, Claus Dieter Schroter, J. Deipenwisch, Jose R. Crespo Lopez-Urrutia, C. Hohr, Paul B. Neumayer, Joachim Hermann Ullrich, Horst Rottke, Christoph Trump, M. Wittmann, Georg Korn, Wolfgang Sandner

Physics Faculty Research & Creative Works

The dynamics of Neon double ionization by 25 fs, 1.0 PW/cm2 laser pulses at 795 nm has been studied in a many particle coincidence experiment. The momentum vectors of all ejected atomic fragments (electrons and ions) have been measured using combined electron and recoil-ion momentum spectroscopy. Electron emission spectra for double and single ionization will be discussed. In both processes the mean electron energies differ considerably and high energetic electrons with energies of more than 120 eV have been observed for double ionization. The experimental results are in qualitative agreement with the rescattering model.

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Determination Of The Pollutant Loads In The Kings River Near Berryville, Thomas S. Soerens, Marc A. Nelson Mar 2001

Determination Of The Pollutant Loads In The Kings River Near Berryville, Thomas S. Soerens, Marc A. Nelson

Technical Reports

An automatic sampler and a U.S. Geological Swvey (USGS) gauging station were established in 1998 and water quality sampling was begun in 1999 on the Kings River near Benyville, Arkansas. Continuous stage and discharge measurements and frequent water quality sampling have been used to determine pollutant concentrations and loads in t11e river. In addition, ten samples were taken by Arkansas Water Resources Center (A WRC) concurrently with USGS samples in order to assess whether A WRC and USGS samples can be compared. This report presents the results from the sampling and analysis for January 1, I999 to December 31, 1999. …

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A Model For Palladium Catalyzed Destruction Of Chlorinated Ethenes In Contaminated Groundwater, Christopher M. Stoppel Mar 2001

A Model For Palladium Catalyzed Destruction Of Chlorinated Ethenes In Contaminated Groundwater, Christopher M. Stoppel

Theses and Dissertations

Groundwater contamination by chlorinated ethenes is a widespread environmental problem. Conventional remediation technologies have shortcomings that have prompted further research into the development of novel treatment technologies. A palladium/ alumina catalyst in the presence of dissolved molecular hydrogen (referred to hereafter as a PD/H2 system) has been demonstrated to rapidly destroy chlorinated ethene contaminated groundwater. First-order kinetics have been used to model chlorinated ethene destruction in a PD/H2 reactor. However, catalyst deactivation and regeneration are important processes that also need to be modeled in order to better understand their effect on treatment efficiency. This study presents a model …

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Gravity Wave Propagation Directions Inferred From Satellite Observations Including Smearing Effects, Jason S. Brown, Michael P. Hickey Ph.D. Mar 2001

Gravity Wave Propagation Directions Inferred From Satellite Observations Including Smearing Effects, Jason S. Brown, Michael P. Hickey Ph.D.

Publications

We simulate space-based, sublimb viewing observations of airglow brightness fluctuations caused by atmospheric gravity wave interactions with the O2 atmospheric airglow, and we demonstrate that because of the geometry associated with such observations, the brightness fluctuations observed for the optically thick 0–0 band emission will always appear stronger for waves traveling toward the observer (the satellite). The effect should be most noticeable for waves having relatively small vertical wavelengths (∼10 km) and horizontal wavelengths of 50 km or greater. For waves of short (∼100 km) horizontal wavelength, the brightness fluctuation anisotropy with respect to viewing direction may also be evident …

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Moving Towards Massively Scalable Video-Based Sensor Networks, Wu-Chi Feng, Jonathan Walpole, Calton Pu, Wu-Chang Feng Mar 2001

Moving Towards Massively Scalable Video-Based Sensor Networks, Wu-Chi Feng, Jonathan Walpole, Calton Pu, Wu-Chang Feng

Computer Science Faculty Publications and Presentations

Networking and computing technologies are becoming advanced enough to enable a wealth of diverse applications that will drastically change our everyday lives. Some past examples of these developments include the World Wide Web and wireless data networking infrastructures. As is quite obvious, the World Wide Web has enabled a fundamental change in the way many people deal with day-to-day tasks. Through the web, one can now make on-line reservations for travel, pay bills through on-line banking services, and view personalized on-line newscasts. More recently, developments in wireless technologies have enabled anywhere, anytime access to information over wireless medium. As wireless …

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Infosphere Project: An Overview, Calton Pu, Jonathan Walpole Mar 2001

Infosphere Project: An Overview, Calton Pu, Jonathan Walpole

Computer Science Faculty Publications and Presentations

We describe the Infosphere project, which is building the systems software support for information-driven applications such as digital libraries and electronic commerce. The main technical contribution is the Infopipe abstraction to support information flow with quality of service. Using building blocks such as program specialization, software feedback, domain-specific languages, and personalized information filtering, the Infopipe software generates code and manage resources to provide the specified quality of service with support for composition and restructuring.

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Modeling The Transient Rate Behavior Of Bandwidth Sharing As A Hybrid Control System, Kang Li, Molly H. Shor, Jonathan Walpole, Calton Pu Mar 2001

Modeling The Transient Rate Behavior Of Bandwidth Sharing As A Hybrid Control System, Kang Li, Molly H. Shor, Jonathan Walpole, Calton Pu

Computer Science Faculty Publications and Presentations

This paper uses hybrid control to model a problem of computer network systems, the dynamic behavior of bandwidth sharing among competing TCP traffic. It has been well known in the computer network community that well-behaved (TCP-friendly) congestion control mechanisms are crucial to the robustness of the Internet. Congestion control determines the transmission rate for each flow. Right now, most TCP-friendly research focuses only on the average throughput behavior without considering how the data is sent out in the short-term (e.g. bursty or smooth). However, recent experimental results show that short-term rate adjustments can change the bandwidth sharing result. Therefore, it …

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Nebraska's Test-Hole Drilling Program And Records, Duane R. Mohlman, Charles A. Flowerday Mar 2001

Nebraska's Test-Hole Drilling Program And Records, Duane R. Mohlman, Charles A. Flowerday

Conservation and Survey Division

No abstract provided.

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Geology Of Pioneers Park, Lancaster County, Nebraska, Roger K. Pabian Mar 2001

Geology Of Pioneers Park, Lancaster County, Nebraska, Roger K. Pabian

Conservation and Survey Division

No abstract provided.

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Validation And Assessment Of Dmsp Electron Temperatures In The Topside Ionosphere, Bradford S. Green Mar 2001

Validation And Assessment Of Dmsp Electron Temperatures In The Topside Ionosphere, Bradford S. Green

Theses and Dissertations

Geomagnetic disturbances in the near earth space environment can adversely affect numerous military and Department of Defense (DoD) systems and operations. To improve the prediction accuracy of such disturbances, the next generation of space environment forecast models aims to automatically ingest real-time ionospheric measurements. This research validates and assesses one such measurement - the Defense Military Satellite Program (DMSP) measured electron temperature (Te). DMSP Te data were validated against near simultaneous incoherent scatter radar (ISR) Te measurements from Millstone Hill, MA and Sondrestrom, Greenland between Winter 1996 and Summer 2000. Of the 37 Millstone and six …

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Information Security: Securing Smart Cards With Iris Recognition, Orval E. Phelps Mar 2001

Information Security: Securing Smart Cards With Iris Recognition, Orval E. Phelps

Theses and Dissertations

This thesis examines the application of iris recognition technology to the problem of keeping smart cards secure. In order to understand the technology, a comprehensive literature review was conducted. The biological components of the iris were examined to ensure that they were truly random in development and static through the lifetime of the individual. Specifically, the physical structure of what comprises the iris was examined in detail. The data gathered indicates that the iris is formed early in development, random in structure, and stable throughout the person's lifetime. Next, the iris recognition process and resulting recognition code was examined to …

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Design And Specification Of Dynamic, Mobile And Reconfigurable Multiagent Systems, Athie L. Self Mar 2001

Design And Specification Of Dynamic, Mobile And Reconfigurable Multiagent Systems, Athie L. Self

Theses and Dissertations

Multiagent Systems use the power of collaborative software agents to solve complex distributed problems. There are many Agent-Oriented Software Engineering (AOSE) methodologies available to assist system designers to create multiagent systems. However, none of these methodologies can specify agents with dynamic properties such as cloning, mobility or agent instantiation. This thesis starts the process to bridge the gap between AOSE methodologies and dynamic agent platforms by incorporating mobility into the current Multiagent Systems Engineering (MaSE) methodology. Mobility was specified within all components composing a mobile agent class. An agent component was also created that integrated the behavior of the components …

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Implementation And Analysis Of The Parallel Genetic Rule And Classifier Construction Environment, David M. Strong Mar 2001

Implementation And Analysis Of The Parallel Genetic Rule And Classifier Construction Environment, David M. Strong

Theses and Dissertations

This paper discusses the Genetic Rule and Classifier Construction Environment (GRaCCE), which is an alternative to existing decision rule induction (DRI) algorithms. GRaCCE is a multi-phase algorithm which uses evolutionary search to mine classification rules from data. The current implementation uses a genetic algorithm based 0/1 search to reduce the number of features to a minimal set of features that make the most significant contributions to the classification of the input data set. This feature selection increases the efficiency of the rule induction algorithm that follows. However, feature selection is shown to account for more than 98 percent of the …

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Hubble Space Telescope Images Of The Ultraluminous Supernova Remnant Complex In Ngc 6946, William P. Blair, Robert A. Fesen, Eric M. Schlegel Mar 2001

Hubble Space Telescope Images Of The Ultraluminous Supernova Remnant Complex In Ngc 6946, William P. Blair, Robert A. Fesen, Eric M. Schlegel

Dartmouth Scholarship

We present Hubble Space Telescope (HST) narrow-passband Hα and [S II] images and broadband continuum images of the region around an extremely luminous optical and X-ray supernova remnant complex in the spiral galaxy NGC 6946. These images, obtained with the PC1 CCD of the Wide Field Planetary Camera 2, show a circular, limb-brightened shell of diameter 035 [9 d/(5.1 Mpc) pc] superposed on the edge of a larger, lower surface brightness elliptical shell (14 × 08, or 34 pc × 20 pc). The HST images allow us to see that the [S II] : Hα ratio remains …

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Isotropy And Factorization In Reduced Witt Rings, Robert W. Fitzgerald Mar 2001

Isotropy And Factorization In Reduced Witt Rings, Robert W. Fitzgerald

Articles and Preprints

We consider reduced Witt rings of finite chain length. We show there is a bound, in terms of the chain length and maximal signature, on the dimension of anisotropic, totally indefinite forms. From this we get the ascending chain condition on principal ideals and hence factorization of forms into products of irreducible forms.

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State Of Tampa Bay 2000, Tampa Bay Regional Planning Council (Tbrpc) Mar 2001

State Of Tampa Bay 2000, Tampa Bay Regional Planning Council (Tbrpc)

Reports

This is the fourteenth edition of the "State of Tampa Bay" Report. It has been prepared by the Agency on Bay Management and funded by the Tampa Bay Regional Planning Council. The Report's primary purpose is to inform our legislators and the general public about the projects and programs underway around Tampa Bay and in its watershed, and the issues and challenges that faced us during 2000 or are expected in 2001.

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Bistable Operation Of A Two-Section 1.3-Mm Inas Quantum Dot Laser—Absorption Saturation And The Quantum Confined Stark Effect, Xiaodong Huang, A. Stintz, Hua Li, Audra Rice, G. T. Liu, L.F. Lester, Julian Cheng, K.J. Malloy Mar 2001

Bistable Operation Of A Two-Section 1.3-Mm Inas Quantum Dot Laser—Absorption Saturation And The Quantum Confined Stark Effect, Xiaodong Huang, A. Stintz, Hua Li, Audra Rice, G. T. Liu, L.F. Lester, Julian Cheng, K.J. Malloy

Faculty Publications

Room temperature, continuous-wave bistability was observed in oxide-confined, two-section, 1.3- m quantum-dot (QD) lasers with an integrated intracavity quantum-dot saturable absorber. The origin of the hysteresis and bistability were shown to be due to the nonlinear saturation of the QD absorption and the electroabsorption induced by the quantum confined Stark effect.

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