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Air Force Institute of Technology

1994

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Articles 1 - 30 of 89

Full-Text Articles in Physical Sciences and Mathematics

Multicriteria Mission Route Planning Using A Parallel A* Search, Michael S. Gudaitis Dec 1994

Multicriteria Mission Route Planning Using A Parallel A* Search, Michael S. Gudaitis

Theses and Dissertations

The Mission Route Planning (MRP) Problem falls into the general class of multicriteria path search problems. Multiple criteria are evaluated to select an optimal aircraft mission route through a hostile environment. Criteria for distance travelled and radar exposure are combined into a single cost function for route evaluation. Radar calculations are performed dynamically. The A* search algorithm is applied to the MRP problem, and a parallel implementation is developed and tested. A unique combination of distributed OPEN lists with a global CLOSED list strategy produced fast execution times on the Paragon. Test cases for scenarios with 15 radars took less …

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A Comparison Of Error Categorization Schemes For Use In Software System Safety Programs, Richard Escobedo, Jim Thomas Dec 1994

A Comparison Of Error Categorization Schemes For Use In Software System Safety Programs, Richard Escobedo, Jim Thomas

Theses and Dissertations

Software safety is becoming increasingly important in the development of DoD advanced weapon systems. To make software safer, hazard conditions must be avoided along with the errors that accompany them. The first step in identifying errors is classifying error data. The area of software error classification is not as advanced as other software development areas. The technical literature lacks examples of comprehensive taxonomies that can be applied to various computer software domains and applications. The predominant approach is to organize errors into categories particular to the program currently in work. The typical error scheme is made of narrow categories that …

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Image Perception Wavelet Simulation And Enhancement For The Visually Impaired, Lemuel Ray Myers Jr. Dec 1994

Image Perception Wavelet Simulation And Enhancement For The Visually Impaired, Lemuel Ray Myers Jr.

Theses and Dissertations

This research delves into the area of image enhancement for the visually impaired. Binocular macular degeneration a visual impairment, affects many Americans; since this condition could not be corrected with conventional glasses the literature suggested using an enhancement system which used a pre-emphasis algorithm to enhance the input image for output to the observer. The work of Dr. Eli Peli, a pioneer in the field of image enhancement, is examine and reproduced. Since his work concentrated mainly on frequency analysis of images, the bulk of this research involves using discrete wavelet analysis to augment that work. A biorthogonal wavelet set …

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Next Generation Real-Time Systems: Investigating The Potential Of Partial-Solution Tasks, Robert E. J. Caley Dec 1994

Next Generation Real-Time Systems: Investigating The Potential Of Partial-Solution Tasks, Robert E. J. Caley

Theses and Dissertations

While the cyclic executive and fixed-priority scheduling strategies have been sufficient to handle traditional real- time requirements. they are insufficient for dealing with the complexities of next-generation real-time systems. New methods of intelligent control must be developed for guaranteeing on-time task completion for real-time systems that are faced with unpredictable and dynamically changing requirements. Implementing real-time processes as partial-solution tasks is one technique that may be beneficial. This type of task. when combined with intelligent control, has the potential for increasing pre-runtime schedulability, system maintainability. and runtime robustness. This research investigates the benefits of partial-solution tasks by experimentally measuring the …

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Survey And Implementation Of Commercial Manual Controllers For A Generic Telerobotics Architecture, Thomas E. Deeter Dec 1994

Survey And Implementation Of Commercial Manual Controllers For A Generic Telerobotics Architecture, Thomas E. Deeter

Theses and Dissertations

The purpose of this study is to determine an input device for the Air Force's generic telerobotics architecture for large aircraft maintenance and repair. One area of concern is the human to machine interface, more specifically, which manual controller should be used for the specified tasks in this architecture. We mailed a survey to 68 companies in order to compile a list of possible input devices that the telerobotics architecture could use. 32 companies responded which gave me enough data to generate a list that described the physical traits of the input devices. We then divided the required tasks into …

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Effects Of Photon Noise On Unconstrained Minimization Techniques For Iterative Blind Deconvolution, Derek K. Davis Dec 1994

Effects Of Photon Noise On Unconstrained Minimization Techniques For Iterative Blind Deconvolution, Derek K. Davis

Theses and Dissertations

In recent years, imaging through atmospheric turbulence has interested military scientists seeking to improve optical surveillance of satellites. Adaptive optics was a step toward achieving diffraction-limited resolution from ground-based telescopes. Unfortunately, adaptive optics only partially compensate for atmospheric blurring, therefore post processing of images is required. Processing methods in use today require knowledge of the impulse response of the optical system to reconstruct imagery, but this information is seldom known. This thesis looks at a new metal of processing compensated imagery, called blind deconvolution, which assumes very little or no a priori information about the impulse response. In particular, this …

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Predicting Protein Structure Using Parallel Genetic Algorithms, George H. Gates Jr. Dec 1994

Predicting Protein Structure Using Parallel Genetic Algorithms, George H. Gates Jr.

Theses and Dissertations

The protein folding problem is a biochemistry Grand Challenge problem. The challenge is to reliably predict natural three-dimensional structures of polypeptides. Genetic algorithms (GAs) are robust, semi-optimal search techniques modeling natural evolutionary processes. Fast messy GAs (fmGAs) are variants of messy GAs that reduce the exponential time complexity to polynomial. This investigation evaluates the merits of parallel SGAs and fmGAs for minimizing the potential energy of a pentapeptide, (Met)-enkephalin. AFIT's energy model is compared to a similar model in a commercial package called QUANTA. Differences between the two models are identified and resolved to enhance GAs' abilities to correctly fold …

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Enhanced Visual User Interface Support For Domain-Oriented Application Composition Systems, Richard A. Guinto Dec 1994

Enhanced Visual User Interface Support For Domain-Oriented Application Composition Systems, Richard A. Guinto

Theses and Dissertations

This research refined the functionality and usability of a previously developed visual interface for a domain-oriented application composition system. The refinements incorporated more sophisticated user interface design concepts1 to reduce user workload. User workload was reduced through window reordering, menu redesign, and Human Computer Interaction techniques such as; combining repetitive procedures into single commands, reusing composition information whenever possible and deriving new information from existing information. The Software Refinery environment, including its visual interface tool INTERVISTA, was used to develop techniques for visualizing and manipulating objects contained in a formal knowledge base of objects. The interface was formally validated with …

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Measurement Of N2+ Mobility In He Via Fourier Transform Emission Spectroscopy, Patrick D. Kee Dec 1994

Measurement Of N2+ Mobility In He Via Fourier Transform Emission Spectroscopy, Patrick D. Kee

Theses and Dissertations

Recently, Hong and Miller used Fourier Transform Emission (FTE) spectroscopy to determine the N2+ mobility in helium by relating the observed Doppler shift of the N2+ (B-X) transition to the measured electric field in the discharge as determined by probes. In order to establish the technique in-house, this effort duplicated that experiment and investigated the sensitivity and utility of the method. Doppler shift measurements in this experiment disagreed significantly with those reported by Hong and Miller. Attempts to reduce the data (and thus determine the mobility) using a model developed by Hong and Miller were unsuccessful. …

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Generation Of A Single-Lobe, Far-Field Intensity Pattern From A Laser Diode Array Using An Optical Delay Line, Thomas A. Summers Dec 1994

Generation Of A Single-Lobe, Far-Field Intensity Pattern From A Laser Diode Array Using An Optical Delay Line, Thomas A. Summers

Theses and Dissertations

A simple and practical technique is demonstrated to generate a stable, single-lobe, far-field intensity pattern from a one-dimensional, antiphased, laser diode array with gain-guided elements. The two far-field lobes of the array are combined after introducing an optical delay line into the path of one of the lobes to make the lobes mutually incoherent. The incoherent superposition of intensities produces a near-diffraction-limited, single-lobe, far-field intensity pattern containing 84% of the power, exceeding any previous (known) phase control experiments. This technique compares favorably with more elaborate schemes advanced previously using integrated phase plates, etc. The method is directly applicable to one-dimensional …

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Artificially Intelligent Air Combat Simulation Agents, Daniel E. Gisselquist Dec 1994

Artificially Intelligent Air Combat Simulation Agents, Daniel E. Gisselquist

Theses and Dissertations

The Advanced Research Projects Agency (ARPA), in an effort to improve military simulations, has proposed a standard for Distributed Interactive Simulation (DIS). This network protocol will allow dissimilar applications to communicate simulation information. In the field of air combat, this will allow pilots in remote simulators to fly in a common simulation. The success of this standard is dependent on applications being able to work within that standard, as well as a large variety of Computer Generated Forces (CGFs) to complement interactive forces. CGFs are needed to help simulate the large combat scenarios that can only occur in wartime. By …

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Using Object-Oriented Database Technology To Develop A Multiple Domain Capability For Domain-Oriented Application Composition Systems, Alfred W. Harris Jr. Dec 1994

Using Object-Oriented Database Technology To Develop A Multiple Domain Capability For Domain-Oriented Application Composition Systems, Alfred W. Harris Jr.

Theses and Dissertations

This thesis describes the design and implementation of a multiple domain capability for a domain-oriented application composition system, named Architect. The research goal was to show how object-oriented database management system (OODBMS) technology can be used to provide simultaneous access to multiple domain-oriented knowledge bases. Since the Architect system was originally designed using the object-oriented paradigm, insertion of OODBMS technology was relatively simple and many of the object-oriented concepts, such as inheritance and aggregation, proved beneficial. Inheritance was used to encapsulate domain knowledge by defining each domain as a subclass of Architect's software architecture. Aggregation was used to allow applications …

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Space Modeler: An Expanded, Distributed, Virtual Environment For Space Visualization, John C. Vanderburgh Dec 1994

Space Modeler: An Expanded, Distributed, Virtual Environment For Space Visualization, John C. Vanderburgh

Theses and Dissertations

The Space Modeler is the first truly immersive virtual environment that models the solar system, models satellites in near-Earth orbit, and can operate in a Distributed Interactive Simulation (DIS) environment. It increases the capabilities of the 1993 Satellite Modeler by expanding the physical limits of the environment and by implementing a new three-dimensional user interface. Satellite orbits are modeled using NASA two line element sets. The positions of the Sun, Moon and planets are computed using an algorithm based on planetary orbital element sets using a linear polynomial fit. For higher precision, the planetary orbits can be computed using an …

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Unification Of Larch And Z-Based Object Models To Support Algebraically-Based Design Refinement: The Z Perspective, Kathleen M. Wabiszewski Dec 1994

Unification Of Larch And Z-Based Object Models To Support Algebraically-Based Design Refinement: The Z Perspective, Kathleen M. Wabiszewski

Theses and Dissertations

This research established a foundation for formalizing the evolution of based object models to theories, part of a dual approach for formally extending object-oriented analysis models using the Z and LARCH languages. For the initial phase, a comprehensive, consistent, and correct Z language parser was implemented within the SOFTWARE REFINERY™ Programming Environment. The Z parser produced abstract syntax trees (ASTs) of objects, thereby forming the basis for analyzing the similarities and differences between the based and LARCH-based object representations. The second phase used the analysis of the two languages to identify fundamental core constructs that consisted of similar syntactic and …

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Detecting Alpha Particles Through Scintillation In Porous Materials, Martin E. Keillor Dec 1994

Detecting Alpha Particles Through Scintillation In Porous Materials, Martin E. Keillor

Theses and Dissertations

This thesis presents the results of a preliminary study of parameters essential to the development of a scintillation flow-cell detector with improved characteristics over existing cells. Such a detector with better than 10% alpha energy resolution could provide in situ capability to detect and identify important alpha-emitting radionuclides in dilute aqueous solutions. Gel-silica is a potential candidate that may provide the needed improvement in resolution while maintaining 100% detection efficiency; however, gel-silica with useful light output is yet to be developed. As a step toward realizing the system described, the dependence of alpha detection efficiency and intrinsic energy resolution on …

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Analysis Of Instability Growth And Collisionless Relaxation In Thermionic Converters Using 1-D Pic Simulations, Bret B. Kreh Dec 1994

Analysis Of Instability Growth And Collisionless Relaxation In Thermionic Converters Using 1-D Pic Simulations, Bret B. Kreh

Theses and Dissertations

This work investigates the role that the beam-plasma instability may play in a thermionic converter. The traditional assumption of collisionally dominated relaxation is questioned, and the beam-plasma instability is proposed as a possible dominant relaxation mechanism. Theory is developed to describe the beam-plasma instability in the cold-plasma approximation, and the theory is tested with two common Particle-in- Cell (PIC) simulation codes. The theory is first confirmed using an unbounded plasma PIC simulation employing periodic boundary conditions, ES1. The theoretically predicted growth rates are on the order of the plasma frequencies, and ESl simulations verity these predictions within the order of …

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Feasibility Exploration Of Throughfold As A Predictor For Target Loading And Associated Error Bounds, Kris G. Rongone Dec 1994

Feasibility Exploration Of Throughfold As A Predictor For Target Loading And Associated Error Bounds, Kris G. Rongone

Theses and Dissertations

Various applications of the Fredholm integral equation appear m different fields of study. An application of particular interest to the Air Force arises in determination of target loading from nuclear effects simulations. Current techniques first unfold the incident spectrum then determine target loading; resulting spectrum and loading are assumed exact. This study investigates the feasibility of a new method, through-fold, for directly determining defensible error bounds on target loading. Through-fold uses a priori information to define input data and represents target response with a linear combination of instrument responses plus a remainder to derive a quadratic expression for exact target …

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Generalized Probabilistic Reasoning And Empirical Studies On Computational Efficiency And Scalability, Eric P. Baenen Dec 1994

Generalized Probabilistic Reasoning And Empirical Studies On Computational Efficiency And Scalability, Eric P. Baenen

Theses and Dissertations

Expert Systems are tools that can be very useful for diagnostic purposes, however current methods of storing and reasoning with knowledge have significant limitations. One set of limitations involves how to store and manipulate uncertain knowledge: much of the knowledge we are dealing with has some degree of uncertainty. These limitations include lack of complete information, not being able to model cyclic information and limitations on the size and complexity of the problems to be solved. If expert systems are ever going to be able to tackle significant real world problems then these deficiencies must be corrected. This paper describes …

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An Analysis Of Bayesian Networks As Classifiers, Gregory C. Ahlquist Dec 1994

An Analysis Of Bayesian Networks As Classifiers, Gregory C. Ahlquist

Theses and Dissertations

An analysis of Bayesian networks as classifiers is presented. This analysis results in an algorithm and several tools related to Bayesian network classifiers. The tools calculate and display the decision regions for two level Bayesian network classifiers. They collectively provide an approach to analyze the effects of changing network parameters on the network's decision regions. The algorithm defines a Bayesian network classifier to solve traditional classification problems. The algorithm is data driven, meaning that the resulting Bayesian network classifier is uniquely tuned to the classification problem at hand. Also, the algorithm contains procedures for defining the topology of a Bayesian …

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Unification Of Larch And Z-Based Object Models To Support Algebraically-Based Design Refinement: The Larch Perspective, Catherine J. Lin Dec 1994

Unification Of Larch And Z-Based Object Models To Support Algebraically-Based Design Refinement: The Larch Perspective, Catherine J. Lin

Theses and Dissertations

This research describes the feasibility of developing object-oriented LARCH specifications, part of a dual approach for formally extending object-oriented analysis models using LARCH and Z. The first phase consisted of two steps establishing a set of transformation heuristics for algebraically representing object models and implementing a robust LARCH parser. The LARCH parser produced abstract syntax trees ASTs of objects forming the basis for analyzing the similarities and differences between Z-based and LARCH-based object representations. The second phase used the analysis of LARCH and Z to identify fundamental core constructs in the languages and abstract syntax trees. These core constructs consisted …

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The Photo-Realistic Afit Virtual Cockpit, Milton E. Diaz Dec 1994

The Photo-Realistic Afit Virtual Cockpit, Milton E. Diaz

Theses and Dissertations

The Air Force Institute of Technology (AFIT) has pursued research in virtual environments since 1988. This research expands the current capabilities of the AFIT Virtual Cockpit (VC) by increasing the realism of the cockpit environment and improving the pilot's command interface. Realism is improved creating console elements from texture maps and polygonal models; these elements include working dials, switches and circuit breakers. The pilot command interface is improved in part by adapting the AFIT Information Pod using a two-dimensional mouse input to the virtual three-dimensional environment. This immersive virtual environment is also improved by modifications to the Head Mounted Display …

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Parallelization Of The 2d Roe Scheme On The Intel Paragon, John R. Graham Iii Dec 1994

Parallelization Of The 2d Roe Scheme On The Intel Paragon, John R. Graham Iii

Theses and Dissertations

This study presented a methodology for determining the general performance characteristics of a computational fluid dynamics (CFD) algorithm on the Intel Paragon. By performing a rigorous time complexity analysis of a parallel CFD algorithm, the general performance could be characterized before the code was actually parallelized. This was shown by implementing a serial version of the 2-D Roe Scheme on the Paragon. This explicit code was parallelized by the addition of generic yet efficient routines that decomposed the domain, automatically adjusted partition indices, and performed 2-D and 3-D buffer exchanges. Additionally, efficient global routines available for the Paragon were used …

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Analytic Performance Models For Parallel Discrete Event Battlefield Simulation With Conservative Synchronization, James B. Hiller Dec 1994

Analytic Performance Models For Parallel Discrete Event Battlefield Simulation With Conservative Synchronization, James B. Hiller

Theses and Dissertations

This study investigated the development and use of analytic models for performance analysis of parallel discrete event battlefield simulation using conservative synchronization. A simulation architecture with layered application, simulation, and host machine services provided the model development basis. Simulation entities were modeled with set-theoretic definitions. Deterministic performance models using these definitions were developed for event prediction, scheduling, and execution in sequential battlefield simulation. The sequential model was expanded to include relative bounds for overhead factors introduced when the simulation is spatially decomposed for a parallel distributed memory machine. Comparison of sequential and parallel models instantiated for a simulation with uniform …

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Modeiing Operational Task Assignment In Air Force Wing Command And Control, Robert J. Hunt Dec 1994

Modeiing Operational Task Assignment In Air Force Wing Command And Control, Robert J. Hunt

Theses and Dissertations

This research investigated the feasibility of applying software engineering technology to the Air Force wing command and control (C2) domain. As part of this research, domain analysis and object-oriented techniques were investigated and a specific approach was chosen to analyze the domain. Analysis of the domain resulted in an object-oriented domain model that captured the key objects, operations, and associations, and behavior of wing C2. The domain model was used to design and implement a prototype software tool that enables wing decision makers to assign resources to mission tasks and to make assessments about automation's impact on wing C2 operations.

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Easy-Sim: A Visual Simulation System Software Architecture With An Ada 9x Application Framework, Jordan R. Kayloe Dec 1994

Easy-Sim: A Visual Simulation System Software Architecture With An Ada 9x Application Framework, Jordan R. Kayloe

Theses and Dissertations

Software architectures increase productivity when used as the basis for developing applications in a problem domain. This thesis describes the creation of Easy-Sim, an object-oriented software architecture for visual simulation systems, and its corresponding implementation as an application framework in Ada 9X. The research built upon ObjectSim, an existing object-oriented simulation architecture implemented as a application framework. Both ObjectSim and Easy-Sim operate on Silicon Graphics platforms and use the IRIS Performer graphics programming library. Easy-Sim is implemented using version 1.83 of the GNAT compiler. The investigation for this thesis involved honing ObjectSim's design, implementing the improved result in both C++ …

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Improving Intrusion Detection In Unix-Based Networks, David R. Landry Dec 1994

Improving Intrusion Detection In Unix-Based Networks, David R. Landry

Theses and Dissertations

Computer security has not kept pace with the rapid growth of networked systems. Through its connection to the Internet, the Department of Defense is vulnerable to computer-based attacks. Current intrusion detection systems are still unproven, too complicated, or too costly for most system security officers to implement. The attack methods used by system intruders are known and can be represented as groups of commands called attack signatures. This thesis investigates methods for detecting intruders by monitoring command usage. Testing was conducted in both controlled and uncontrolled circumstances. With controlled testing, it was shown that 7 of the 11 signatures could …

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Development Of A Mammographic Image Processing Environment Using Matlab, John L. Kelley Dec 1994

Development Of A Mammographic Image Processing Environment Using Matlab, John L. Kelley

Theses and Dissertations

Breast cancer is a disease that accounts for a disturbingly large number of deaths in females each year. Its prevalence is a topic of concern to all of us since it can affect our families, friends, and coworkers. Although mammographic screening is the most effective method currently available for the early detection of breast cancer, it is far from being an infallible procedure. Mammographic reading is error prone, partly because of the complexity of the task and partly because of the variability in human performance. Computers offer high reproducibility, and when used as an adjunct by the radiologist, may improve …

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Designing And Implementing An Ada Language Binding Specification For Odmg-93, Stephen R. Lindsay Dec 1994

Designing And Implementing An Ada Language Binding Specification For Odmg-93, Stephen R. Lindsay

Theses and Dissertations

Object-oriented database management systems (ODBMSs) represent the latest advancement in database technology, combining the reusability and maintainability of the object-oriented programming paradigm with the ability to efficiently store and retrieve a wide range of data types as well as code to manipulate stored data. Unfortunately, programmers developing software in the Ada programming language do not have the ability to interface to object databases without significant customized code development. One important reason for this has been the absence of a standard defining the constructs accessing ODBMS functionality. This thesis documents the creation of an Ada language binding to the ODMG-93 standard …

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A General Object Model Transformation System, John P. Mullaney Dec 1994

A General Object Model Transformation System, John P. Mullaney

Theses and Dissertations

Cecil and Fullenkamp developed a program that transforms knowledge captured in an object-model in one environment into a different object-model in a different environment. This program worked well for the intended purpose, but if one of the object-models is replaced by a different object-model then this transformation program has to be re-engineered. As the object-modeling paradigm becomes more prevalent, many systems are experiencing this problem. The primary goal of this research was to determine what reusable knowledge could be extracted from these types of program and used to build a general object-model transformer that generalizes such transformation programs. Toward this …

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A Numerical Model To Predict The Fate Of Jettisoned Aviation Fuel, Karl D. Pfeiffer Dec 1994

A Numerical Model To Predict The Fate Of Jettisoned Aviation Fuel, Karl D. Pfeiffer

Theses and Dissertations

While airborne, military and civilian aircraft must occasionally jettison unburned aviation fuel into the atmosphere. This research investigates the fate of a jettisoned fuel (e.g. JP-4, JP-8, etc.) from initial release to final ground fall by numerically modeling the physical phenomena governing the fate of this fuel: evaporation, advection, and dispersion. Using previous work in evaporation and free fall of fuel droplets as a foundation, this thesis presents an integrated evaporation advection and dispersion model designed to run under the resources of a typical personal computer. This integrated model is capable of using near real-time meteorological data (i.e. vertical profiles …

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