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1999

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Articles 1201 - 1230 of 2555

Full-Text Articles in Physical Sciences and Mathematics

A Modeling And Simulation Approach To Analyze The Workload Associated With The Growth Of Network Router Access Control Lists, Douglas R. Lomsdalen Mar 1999

A Modeling And Simulation Approach To Analyze The Workload Associated With The Growth Of Network Router Access Control Lists, Douglas R. Lomsdalen

Theses and Dissertations

Organizations can no longer isolate their networks from the rest of the world and still remain competitive. An organization willing to compete in the world market must take the necessary precautions to protect its network, the systems located on those networks, and its mission critical data. There are performance issues associated with the use of access control lists (ACL); however, if ACLs are implemented properly and periodically reviewed, a secure network can be attained. This research attempts to determine how the growth of an ACL affects packet flow and router CPU consumption, and also identify the specific length of an …


An Improved Thunderstorm Forecast Index For Cape Canaveral, Florida, James A. Everitt Mar 1999

An Improved Thunderstorm Forecast Index For Cape Canaveral, Florida, James A. Everitt

Theses and Dissertations

This thesis creates a new algorithm to replace the Neumann-Pfeffer Thunderstorm Index (NPTI). The 45th Weather Squadron at Patrick AFB, Florida, uses the NPTI as an objective means of determining the probability of thunderstorm occurrence at Cape Canaveral. The probability is used for mission planning and resource protection, and increasing the accuracy of NPTI can potentially save billions of dollars for the United States space program. Stratified logistical regressions are performed and probability equations are derived for May through September using upper air data and surface observations for Cape Canaveral. A logistical regression of NPTI was also performed. Variables include …


Gps Signal Offset Detection And Noise Strength Estimation In A Parallel Kalman Filter Algorithm, Barry J. Vanek Mar 1999

Gps Signal Offset Detection And Noise Strength Estimation In A Parallel Kalman Filter Algorithm, Barry J. Vanek

Theses and Dissertations

Measurements from Global Positioning System (GPS) satellites are subject to corruption by signal interference and induced offsets. This thesis presents two independent algorithms to ensure the navigation system remains uncorrupted by these possible GPS failures. The first is a parameter estimation algorithm that estimates the measurement noise variance of each satellite. A redundant measurement differencing (RMD) technique provides direct observability of the differenced white measurement noise samples. The variance of the noise process is estimated and provided to the second algorithm, a parallel Kalman filter structure, which then adapts to changes in the real-world measurement noise strength. The parallel Kalman …


Fisheries Research Report No. 113 - Catch, Effort And The Conversion From Gill Nets To Traps In The Peel-Harvey And Cockburn Sound Blue Swimmer Crab (Portunus Pelagicus) Fisheries, Roy Melville-Smith, Mark Cliff, Sonia M. Anderton Mar 1999

Fisheries Research Report No. 113 - Catch, Effort And The Conversion From Gill Nets To Traps In The Peel-Harvey And Cockburn Sound Blue Swimmer Crab (Portunus Pelagicus) Fisheries, Roy Melville-Smith, Mark Cliff, Sonia M. Anderton

Fisheries research reports

Over the last few years, there has been considerable interest on the part of commercial fishers to move away from using gill nets, the traditional method for fishing for blue swimmer crabs in Western Australia (WA), to fishing with traps. Blue swimmer crab fisheries in WA are regulated by effort controls and most gill net fishers are restricted to hauling 1,000 metres (1,200 metres in the case of Cockburn Sound) of gill net per day.

The fieldwork in this study was initiated in March 1994 in Cockburn Sound and in January 1996 in the Peel-Harvey Estuary. It was aimed at …


Deuel County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 25, Robert F. Diffendal Jr. Mar 1999

Deuel County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 25, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

In 1930, the Conservation and Survey Division (CSD) of the University of Nebraska and the United States Geological Survey began a program of cooperative groundwater studies in Nebraska. Since then test drilling by use of rotary drilling equipment has been an integral part of that program. This report contains logs of all the test holes drilled in the county under the program as well as those drilled by the Conservation and Survey Division with financial assistance from other government agencies.

The map in this report shows the location of all test holes drilled in the county since 1942.

Present techniques …


Mountain Evolution And Environmental Changes Of Huangshan (Yellow Mountain), China, Pei-Hua Huang, Robert F. Diffendal Jr., Min-Qing Yang, Patricia E. Helland Mar 1999

Mountain Evolution And Environmental Changes Of Huangshan (Yellow Mountain), China, Pei-Hua Huang, Robert F. Diffendal Jr., Min-Qing Yang, Patricia E. Helland

Department of Earth and Atmospheric Sciences: Faculty Publications

Huangshan (Yellow Mountain) is located in southern part of the lower reaches of the Yangtze River. The highest Lotus Flower peak is 1,864 m above sea level. Formative ages of the Huangshan and its granite, process of mountain geomorphic evolution from the Eocene to Quaternary, environmental changes of Quaternary, formative origin of beautiful peaks and fascinating rocks were studied and the questionable “Pleistocene glaciation” was also discussed in this paper.


Molecular Mechanics Simulations Of The Three Dimensional Cavity Problem, Donald Greenspan Mar 1999

Molecular Mechanics Simulations Of The Three Dimensional Cavity Problem, Donald Greenspan

Mathematics Technical Papers

The rapid development of computer technology has resulted in broad interest in three dimensional fluid simulation, which is known to have more complex force interactions than occur in two dimensions (see, e.g., refs. [1-6], [9], [11-15], [17], [18] and the additional references therein). In this paper we develop and analyze some molecular mechanics simulations of the three dimensional cavity problem. The fluid considered is water at 15° C.


Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 3, March 1999, College Of Engineering And Computer Science, Wright State University Mar 1999

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 3, March 1999, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A ten page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.


Final Environmental Impact Statement Related To Reclamation Of The Uranium Mill Tailings At The Atlas Site, Moab, Utah, Division Of Waste Management, Office Of Nuclear Material Safety And Safeguards, U.S. Nuclear Regulatory Commission Mar 1999

Final Environmental Impact Statement Related To Reclamation Of The Uranium Mill Tailings At The Atlas Site, Moab, Utah, Division Of Waste Management, Office Of Nuclear Material Safety And Safeguards, U.S. Nuclear Regulatory Commission

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

This Final Environmental Impact Statement (FEIS) has been prepared by the Nuclear Regulatory Commission (NRC), Office of Nuclear Material Safety and Safeguards, to address potential environmental impacts associated with a request by Atlas Corporation to amend its existing NRC License no. SUA-917 to reclaim in place an existing uranium mill tailings pile near Moab, Utah. The proposed reclamation would allow Atlas to (1) reclaim the tailings pile for permanent disposal and long-term custodial care by a government agency in its current location on the Moab site, and (2) prepare the 162-ha (400-acre) Moab site for closure. the FEIS describes and …


Classification Of Great Basin Plant Communities Occurring On Dugway Proving Ground, Utah, Vel Emrick, Alison Hill Mar 1999

Classification Of Great Basin Plant Communities Occurring On Dugway Proving Ground, Utah, Vel Emrick, Alison Hill

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

No abstract provided.


Load Dependent Single Chain Models Of Multichain Closed Queueing Networks, Amy Apon, Lawrence Dowdy Mar 1999

Load Dependent Single Chain Models Of Multichain Closed Queueing Networks, Amy Apon, Lawrence Dowdy

Publications

No abstract provided.


A Continuous Wave Atomic Bromine Laser Produced By Photolysis Of Iodine Monobromide, Brian A. Smith Mar 1999

A Continuous Wave Atomic Bromine Laser Produced By Photolysis Of Iodine Monobromide, Brian A. Smith

Theses and Dissertations

An apparatus to generate continuous wave (CW) lasing at 2.714 µm by Br(2P1/2) atoms produced from photodissociation of IBr was designed, constructed and tested. A frequency doubled Nd:YAG laser firing 8 ns, 850 mJ pulses at 532 nm was used to photodissociate static IBr vapor inside a flow nozzle. The CaF2 windows on either side of the nozzle proved to have a damage threshold below the threshold for lasing. Pulsed lasing in static mode was not observed. Therefore, CW lasing in flow mode, using an Ar+ laser at 488 nm, could not be investigated.


Incorporating Scene Mosaics As Visual Indexes Into Uav Video Imagery Databases, Timothy I. Page Mar 1999

Incorporating Scene Mosaics As Visual Indexes Into Uav Video Imagery Databases, Timothy I. Page

Theses and Dissertations

The rise of large digital video archives has strengthened the need for more efficient ways of indexing video files an accessing the information contained in them. Reconnaissance platforms, such as the Predator UAV, are contributing thousands of hours of video footage that require analysis, storage, and retrieval. A process is proposed for converting a video stream into a series of mosaic and selected still images that provide complete coverage of the original video. The video mosaic images can be utilized as visual indexes into a video database. In addition, mosaic images contain information from an entire sequence of video frames …


A Comparison Of Horizontal Cloud-To-Ground Lightning Flash Distance Using Weather Surveillance Radar And The Distance Between Successive Flashes Method, Christopher C. Cox Mar 1999

A Comparison Of Horizontal Cloud-To-Ground Lightning Flash Distance Using Weather Surveillance Radar And The Distance Between Successive Flashes Method, Christopher C. Cox

Theses and Dissertations

On April 29th, 1996 an airman servicing a C-130 aircraft on Huriburt AFB Florida was struck and killed by a lightning flash that traveled an estimated 7 to 10 miles from storms south of the airfield. Ten other workers were injured in the incident. The fatal flash occurred just 8 minutes after the base weather station allowed a lightning advisory to expire. The incident brought to question the adequacy of lightning advisory criteria. Very little research has been done on the horizontal distance that cloud-to-ground lightning flashes occurs from the center of a thunderstorm. This thesis used the WSR-88D method, …


A Validation Study Of Cloud Scene Simulation Model Temporal Performance, Glenn Kerr Mar 1999

A Validation Study Of Cloud Scene Simulation Model Temporal Performance, Glenn Kerr

Theses and Dissertations

Cloud Scene Simulation Model (CSSM) temporal performance was validated by comparing the cloud forcing signatures on observed radiometric time series with those derived from CSSM output for initial conditions similar to that for the observed data. Observed radiometric data was collected by a normal incidence pyraheliometer sensitive to wavelengths in the range .3mm to 3mm. Simulation radiometric time series data was derived by applying the following process to each case study. CSSM cloud liquid water content (CLWC) grids were converted to grids of slant path optical depth values by the Fast Map post processor to the CSSM. A ray tracing …


Transforming Cobol Legacy Software To A Generic Imperative Model, Dina L. Moraes Mar 1999

Transforming Cobol Legacy Software To A Generic Imperative Model, Dina L. Moraes

Theses and Dissertations

Legacy COBOL code presents challenges for organizations wishing to increase their effectiveness and improve their efficiency. The systems that utilize this code are vital to enterprise operations, yet maintenance of code is expensive. This research presents an alternative that overcomes some of the problems of legacy COBOL code through the use of software reengineering techniques. This research develops a transformation system to convert COBOL code into a generic imperative model, recapturing the initial design and deciphering the requirements implemented by the legacy code, thereby making possible the documentation of legacy systems, design restructuring, and the re-design of a new, enhanced …


Predicting Launch Pad Winds At The Kennedy Space Center With A Neural Network Model, Steven J. Storch Mar 1999

Predicting Launch Pad Winds At The Kennedy Space Center With A Neural Network Model, Steven J. Storch

Theses and Dissertations

This thesis uses neural networks to forecast winds at the Kennedy Space Center and the Cape Canaveral Air Station launch pads. Variables are developed from WINDS tower observations, surface and buoy observations, and an upper-air sounding. From these variables, a smaller set of predictive inputs is chosen using a signal-to-noise variable screening method. A neural network is then trained to forecast launch pad winds from the inputs. The network forecasts are compared to persistence, and peak wind predictions are found skillful compared to persistence. An ensemble modeling technique using Toth's and Kalnay's breeding of growing modes method is explored with …


Computation Of Scattering From Bodies Of Revolution Using An Entire-Domain Basis Implementation Of The Moment Method, Arthur P. Ford Iv Mar 1999

Computation Of Scattering From Bodies Of Revolution Using An Entire-Domain Basis Implementation Of The Moment Method, Arthur P. Ford Iv

Theses and Dissertations

Research into improved calibration targets for measurement of radar cross-section has created a need for the ability to accurately compute the scattering from perfectly conducting bodies of revolution. Common computational techniques use Moment Method codes that employ subdomain basis functions to expand the unknown current density. This approach has its shortcomings. Large numbers of basis functions are required, and increasing the number of basis functions to improve accuracy after an initial computation requires re-computation of previous results and lost processing time. This research involves using basis functions that have as their domain the entire length of the surface. Entire-domain basis …


Modeling Chemical Absorption Through Membranes, Jeffrey M. Hemmes Mar 1999

Modeling Chemical Absorption Through Membranes, Jeffrey M. Hemmes

Theses and Dissertations

Understanding the processes involved in dermal penetration of chemicals and drugs is important to both toxicologists and pharmacologists. Researchers developing new drugs are interested in enhancing the penetration of chemicals through the skin, while environmental professionals are interested in limiting such penetration. For both types of applications, predictive biologically-based mathematical models can be very useful in understanding the processes involved, particularly when such models are based on physiological and biochemical parameters which can be measured experimentally. In this thesis we study two existing physiologically-based pharmacokinetic (PBPK) models that predict concentrations of neat and aqueous dibromomethane (DBM) absorbed into and through …


Numerical Solutions To The Two Dimensional Boltzmann Equation, Christopher G. Smithtro Mar 1999

Numerical Solutions To The Two Dimensional Boltzmann Equation, Christopher G. Smithtro

Theses and Dissertations

A strict kinetic, two-dimensional model of the electron kinetics within a glow discharge positive column is developed. The problem is solved in cylindrical geometry using the standard two-term Legendre expansion of the electron velocity distribution function. The model establishes a steady state solution, such that the net ionization rate is exactly balanced by the wall loss. In addition to a thorough analytic development, we present the numerical techniques used to solve the resulting elliptic partial differential equation, including an efficient method to treat sparse banded matrices. The model is validated against published results, local and nonlocal kinetic approximations, and a …


Field Evaluation Of Radiotransmitters For Northern Pocket Gophers, Gary W. Witmer, Michael Pipas Mar 1999

Field Evaluation Of Radiotransmitters For Northern Pocket Gophers, Gary W. Witmer, Michael Pipas

United States Department of Agriculture Wildlife Services: Staff Publications

A field study was conducted in northern Idaho from June to November 1995 to evaluate the design and functional aspects of four types of Radio-transmitters for use on northern pocket gophers (Thomomys talpoides) as well as the effects of the transmitters on behavior of the animals. Twenty-five of 46 northern pocket gophers were fitted in the field with one of three models of radio-collars (AVM, NWRC, and Holohil), nine received Wildlife Materials abdominal implant transmitters (surgery conducted off-site), and 12 without transmitters served as controls. Study animals were relocated every second to fourth day until the end of …


Seagrass And Caulerpa Monitoring In Hillsborough Bay Tenth Annual Report, City Of Tampa Department Of Sanitary Sewers Mar 1999

Seagrass And Caulerpa Monitoring In Hillsborough Bay Tenth Annual Report, City Of Tampa Department Of Sanitary Sewers

Reports

This is the tenth annual report to FDER to satisfy the requirements set forth in specific condition #14 of FDER construction permit DO29-1845321B.

The City of Tampa, Bay Study Group (BSG), has monitored the effects of sewage pollution abatement in Hillsborough Bay since 1976. Within the last decade, water quality improvements and evidence of minor seagrass revegetation in Hillsborough Bay prompted the BSG to initiate a seagrass study to compliment other programs assessing the environmental status of Hillsborough Bay.


Structural Emergence And The Collaborative Behavior Of Autonomous Nano-Satellites, Daniel J. Petrovich Mar 1999

Structural Emergence And The Collaborative Behavior Of Autonomous Nano-Satellites, Daniel J. Petrovich

Theses and Dissertations

The collaborative behavior of nano-satellites in a zero-gravity environment is explored, and satellite characteristics are proposed that maximize constellation robustness and minimize manufacturing costs. Behavioral algorithms are proposed to facilitate both swarming and structural formation and are validated using the Structural Emergence Simulator (STEMS) Graphical User Interface (GUl). A payload of multiple satellites is placed in a zero-gravity environment and released to re-configure autonomously into a pre-designed structure. Data transmission between satellites is not permitted during the swarming phase of the structure formation mission. A binary behavior algorithm is invented that produces a direction and magnitude solution to the satellite …


Center For Sustainable Agricultural Systems Newsletter, March/April 1999 Mar 1999

Center For Sustainable Agricultural Systems Newsletter, March/April 1999

Center for Sustainable Agricultural Systems: Newsletters (1993-2000)

Contents:

We Came! We Saw! We Heard!

University Role in Biotechnology: Who Benefits From New Technologies?

Highlights of Upcoming Book: Under The Blade (Part 6)

Study Finds Consolidation Harms Nation's Consumers And Farmers

National Ag Biotech Meeting in Lincoln

Nordic Agroecology Course Welcomes Students

Agroecology Field Course Offered


High-Grade Paper Recycling: A Program Management Perspective, Rodger L. Carter Mar 1999

High-Grade Paper Recycling: A Program Management Perspective, Rodger L. Carter

Theses and Dissertations

Recycling of high-grade paper is one method of reducing the use of natural resources and the amount of waste being emitted into the environment, both in the process of manufacturing and in the disposal of unneeded documents. The Air Force Materiel Command (AFMC) is a significant user of high-grade paper, thus recycling represents a potential saving to society in the form of lessened negative impact on the environment as the result of AFMC operations. The possibility also exists for AFMC to reduce operating costs. The purpose of this study is to explore means of reducing high-grade paper disposal by AFMC, …


Analysis Of Usaf Battlelabs' Communication Infrastructure Over Various Protocols, Rocky A. Favorito, David M. Mcillece Mar 1999

Analysis Of Usaf Battlelabs' Communication Infrastructure Over Various Protocols, Rocky A. Favorito, David M. Mcillece

Theses and Dissertations

As a result of the doctrines exposed in the Air Force's "Global Engagement: A Vision for the 21st Century Air Force," the concept of a "Battlelab" was devised to support and develop the key warfighting capabilities needed in the next century. Although geographically separated, these labs must have the capability to exchange information with each other in a "Virtual Battlelab Environment" (VBE). Although many types of data will be exchanged, only variable-bit-rate (VBR) video and distributed interactive simulation (DIS) traffic are modeled in the VBE. The research described in this thesis utilizes a systems engineering approach to investigate the performance …


Inelastic Scattering Matrix Elements For The Collision B (2P1/2) + H2(J) → B (2P3/2) + H2(J'), Thomas A. Niday Mar 1999

Inelastic Scattering Matrix Elements For The Collision B (2P1/2) + H2(J) → B (2P3/2) + H2(J'), Thomas A. Niday

Theses and Dissertations

Initial efforts to characterize the scattering dynamics of B + H2 focus on computing scattering matrix elements for the fine structure transition B (2P1/2) --> B (2P3/2) in collisions with H2, allowing for rotational excitation. Using a new application of the time dependent Channel Packet Method (CPM), reactant and product wave packets are prepared in the asymptotic limit on the B (2P1/2) and B (2P3/2) surfaces. They are propagated using the split operator method together wit a unitary transformation between the …


Double Layer Effects On Shock Wave Propagation, Shannon L. Walker Mar 1999

Double Layer Effects On Shock Wave Propagation, Shannon L. Walker

Theses and Dissertations

An analysis and assessment of two mechanisms in plasma shock interactions was conducted under conditions typically encountered in a weakly ionized glow discharge. The mechanisms of a spatially-dependent electron temperature and additional electron impact ionization at the shock front were examined for effects on shock structure and propagation. These mechanisms were incorporated into an existing one-dimensional, time-dependent, fluid dynamics code that uses the Riemami problem as a basis and numerically solves the Euler equations for two fluids: the neutral gas and the charged component. The spatial variation in electron temperature was modeled as a shock-centered rise in temperature. Additional ionization …


Strategies For Steganalysis Of Bitmap Graphics Files, Christopher J. Fogle Mar 1999

Strategies For Steganalysis Of Bitmap Graphics Files, Christopher J. Fogle

Theses and Dissertations

Steganography is the art and science of communicating through covert channels. The goal of steganography is to hide the fact that a message is even being transmitted. In the context of today's digital world, this ancient practice is enjoying resurgence due to the plethora of hiding places made possible by modern information media. Of particular concern is the use of graphics image files to conceal both legitimate and criminal communications.


Transforming Aggregate Object-Oriented Formal Specifications To Code, John A. Kissack Mar 1999

Transforming Aggregate Object-Oriented Formal Specifications To Code, John A. Kissack

Theses and Dissertations

The feasibility of a transformational formal-based software engineering tool has been the focus of AFIT research for several years. Until now, the main research emphasis has been placed on the individual components that would comprise such a transformational system; therefore, this research demonstrates how a representative collection of aggregate objects would be transformed from specification to code. The research focused on critical integration issues associated with a formal-based software transformation system, such as the source specification, the problem space architecture, design architecture, design transforms, and target software transforms. Software is critical in today's Air Force, yet its specification, design, and …