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Air Force Institute of Technology

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Articles 2971 - 3000 of 3047

Full-Text Articles in Physical Sciences and Mathematics

Design And Testing Of A Lightweight, Planar Microwave Lens, Paul M. Proudfoot Dec 1991

Design And Testing Of A Lightweight, Planar Microwave Lens, Paul M. Proudfoot

Theses and Dissertations

This thesis documents the design, fabrication, and testing of a lightweight, planar microwave lens. The lens consists of two planar arrays of lightweight printed circuit antennas interconnected by microstrip lines whose length varies as a function of position on the lens. Microwave energy is coupled from one face of the lens to the other by means of a slot etched in the ground plane. At 8.0 GHz the lens is ten wavelengths across, is less than 1/8 inch thick, and weighs less than 4 pounds. The lens can scan a beam over a +/- 30 degree region in both the …

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Binary Programming Models Of Spatial Pattern Recognition: Applications In Remote Sensing Image Analysis, Thomas G. Reed Dec 1991

Binary Programming Models Of Spatial Pattern Recognition: Applications In Remote Sensing Image Analysis, Thomas G. Reed

Theses and Dissertations

The major purpose of this investigation was to implement subregion allocation objectives using a network model base on an existing subregion allocation binary programming model (Benabdallah and Wright (B&W), 1990), the ultimate goal being the application of subregion allocation concepts towards the spatial analysis of satellite imagery. The multi-objective aspects of subregion allocation can be accomplished via a network formulation, a formulation vastly simpler in complexity than the binary programming models previously used. Without a network programming package that could maintain integral flows, however, deriving the solution was a tiresome task for the user. Nonetheless, several new concepts and advantages …

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Gaseous Component Identification With Polymeric Film Sensor, Edward S. Kolesar Jr. Sep 1991

Gaseous Component Identification With Polymeric Film Sensor, Edward S. Kolesar Jr.

AFIT Patents

A sensor having an interdigitated gate electrode field effect transistor (IGEFET) coupled to an electron beam evaporated copper phthalocyanine thin film is used to selectively detect parts-per-billion concentration levels of atmosphere contaminants such as nitrogen dioxide (NO2) and diisopropyl methylphosphonate (DIMP). The sensor is excited with a voltage pulse, and its time- and frequency-domain response are examined. The envelopes of the magnitude of the normalized difference frequency spectrums reveal features which unambiguously distinguish the NO2 and DIMP exposures.

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Education Necessary For Air Force Software Managers To Use The Ada Programming Language And Software Engineering Effectively, James W. Worley Jr. Sep 1991

Education Necessary For Air Force Software Managers To Use The Ada Programming Language And Software Engineering Effectively, James W. Worley Jr.

Theses and Dissertations

This research investigated the perceived Ada and software engineering education needs of software managers throughout the Air Force and provided recommendations to Air Staff for developing the education. Since the Department of Defense mandated all DOD agencies use the Ada programming language for software development, the education of the personnel who have to support the policy has lagged behind the implementation Ada is not a simple language to use and is only fully effective if used with sound software engineering principles. A survey was given to Air Force mid-level personnel who manage software in some capacity. Of the software personnel …

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An Application Of Artificial Intelligence Technology Within The Standard Base Supply System, Richard G. Nelson Sep 1991

An Application Of Artificial Intelligence Technology Within The Standard Base Supply System, Richard G. Nelson

Theses and Dissertations

This thesis investigated the feasibility of applying artificial intelligence technology within the Standard Base Supply System (SBSS). With assembly endless reductions in manpower authorizations within the SBSS and the potential for a continued loss of expert knowledge, the use of knowledge-based system (KBSs) was examined to determine if these systems could alleviate this of manpower. Literature related to the fields of artificial intelligence, expert systems, and KBSs was traced, yielding a methodology for identifying candidate problems, and for the development, verification, and validation of prototype KBSs. This methodology was then employed within the research, culminating in the creation, verification, and …

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An Expert System Job Aid For Users Of The Automated Scheduling Module, Kevin A. Gore Sep 1991

An Expert System Job Aid For Users Of The Automated Scheduling Module, Kevin A. Gore

Theses and Dissertations

This research developed an Expert System for novice aircraft maintenance schedulers (AFSC: 392XX) with little experience using the Automated Scheduling Module (ASM). First, an in-depth literature review was completed. Next, personal interviews were conducted with an ASM expert and other 392XX personnel. Prototypes using VP-Expert and KnowledgePro shells were created. The knowledgePro shell was selected to create the ASM Job Aid, combining the knowledge of the expert and AFM 66-279. The program was verified, validated, and favorably reviewed by 392XX personnel. Recommendations include: The Air Force Logistics Management Center (AFLMC) examine the ASM Job AId and develop a Performance Support …

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A Topological Model For Parallel Algorithm Design, Jeffrey A. Simmers Sep 1991

A Topological Model For Parallel Algorithm Design, Jeffrey A. Simmers

Theses and Dissertations

This research demonstrates that formal, mathematical analysis in theoretical computer science can be recast in terms of the topology of complete metric spaces, and also presents a methodical technique for developing formal specifications. This effort shows that the topology of complete metric spaces provides a tool that can be used to both recreate major results about computational models and also to develop new results about these models. Using the two computational models CSP and UNITY, this effort shows that the required mathematics needed to support this alternative to the traditional analysis of computational models can be readily supported by a …

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An Application Of Interactive Computer Graphics To The Study Of Inferential Statistics And The General Linear Model, Stephen D. Pearce Sep 1991

An Application Of Interactive Computer Graphics To The Study Of Inferential Statistics And The General Linear Model, Stephen D. Pearce

Theses and Dissertations

This research created a learning environment, known as the Pearce Projection Modeling Environment (PPME) which is used as a tool by a teacher and student. The PPME was developed in an effort to create a new approach to the study of the General Linear Model through a constructive and projective, geometric approach. While the geometric approach to the GLM was developed over the past century, it has not been used extensively because of the inherent complexities associated with visualizing vector spaces. With the PPME, visualization is accomplished effortlessly. The PPME is a computer program that allows the student to enter …

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Heuristics For Hospital Inventory Management, Thomas G. Hibson Sep 1991

Heuristics For Hospital Inventory Management, Thomas G. Hibson

Theses and Dissertations

This study investigated the reasoning strategies used by hospital logistics management experts and was conducted at the Wright-Patterson AFB (WPAFB) Medical Center. An expert system was developed to verify the captured strategies. The particular area of interest of this study was the reasoning strategies involved in the reconciliation of the Monthly Stock Status Report within the Medical Logistics Branch. A literature review revealed there were few guidelines as to when and what action to pursue when reconciling the Monthly Stock Status Report. Though there were no references in the literature on expert systems that dealt with this particular report, there …

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Collisional Dynamics Of The B3Π(O+) State Of Bromine Of Monofluoride, David W. Melton Aug 1991

Collisional Dynamics Of The B3Π(O+) State Of Bromine Of Monofluoride, David W. Melton

Theses and Dissertations

When Bromine is combined with flourine atoms and discharged oxygen in a flow tube is produced in a highly non thermal distribution peaking at v'=3. The emission was linearly dependent on the concentration. The observed dependence of the BrF(B) emission on Bromine and atomic oxygen is inconsistent with a steady state prediction of a sequential excitation mechanism, where BrF(X) is excited by successive collisions with singlet oxygen. The experimental data are consistent with a three body mechanism involving Br and F atoms. Electronic quenching of BrF(B) by a number of collision partners (Br2, CO2, O2 …

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An Ada Based Expert System For The Ada Version Of Satool Ii, Min-Fuh Shyong Jun 1991

An Ada Based Expert System For The Ada Version Of Satool Ii, Min-Fuh Shyong

Theses and Dissertations

This thesis continues the work of implementing the expert system for the Ada version of SAtool II, an software design requirement analysis tool. The background, history, design process together with the design results and validation of the implementation with Ada and CLIPS/Ada is presented.

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Quenching And Rotational Energy Transfer In Molecular Bromine: Br2(B), Dean A. Massman May 1991

Quenching And Rotational Energy Transfer In Molecular Bromine: Br2(B), Dean A. Massman

Theses and Dissertations

This study investigates the rotational energy transfer processes of optically excited bromine molecules in the presence of several collision partners. Resolved laser induced fluorescence spectra of collisionally populated rotational states were analyzed by means of Stern Volmer analysis. Total rotational removal rate coefficients and state-to-state rotational removal rate coefficients for the v'=11,J'=35 level of Br2(B) were obtained for collisions with Br2(X), He, Ar and Xe. Rotational removal rate coefficients were also obtained for the v'11, J'=26 and 47; v'=14, J'=36 states of Br2(B) with collisions with Ar. Total rotational removal rate for Br2 self quenching found to be 3.98+/-0.2x10-10 (cm3/Molec-Sec). …

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Modifications To Mcnp, Version 3b: Incorporating A Variable Density Atmosphere. Addendum, David L. Monti, Kirk A. Mathews Mar 1991

Modifications To Mcnp, Version 3b: Incorporating A Variable Density Atmosphere. Addendum, David L. Monti, Kirk A. Mathews

AFIT Documents

MCNP version 3B was modified to incorporate a continuously variable density atmosphere. This was accomplished by representing the variation of air density as a function of altitude with a series of continuous piecewise exponential curves up to a maximum altitude of 1000 km. User-written subroutines and functions were written which incorporated these piecewise functions. These subroutines and functions were subsequently incorporated into a production version of MCNP. Several MCNP subroutines and files were modified in support of these modifications. This report discusses detailed information regarding the theoretical development of the variable density model, the user written subroutines and functions, the …

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Mapping Efficient Numerical Methods To The Solution Of Multiple Objective Linear Programs, Michael A. Shields Mar 1991

Mapping Efficient Numerical Methods To The Solution Of Multiple Objective Linear Programs, Michael A. Shields

Theses and Dissertations

This investigation was initiated to increase the speed, accuracy and capacity of m-simplex algorithms for solving multiple objective linear programming problems. Specifically, improvements were sought through the application of general numerical techniques. It soon became apparent that the m- simplex algorithm, like the simplex algorithm, is heavily dependent upon the technology of solving related systems of linear equations. The numerical arguments for the application of LU triangular matrix factorization techniques to simplex computations are well known. OF special significance to m-simplex performance is the case of rank-k updates to basis factorizations. A stable and efficient LU approach to the rank-k …

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A Goodness-Of-Fit Test For A Family Of Two Parameter Weibulls With Known Shape Using Minimum Distance Estimation Of Parameters, John S. Crown Mar 1991

A Goodness-Of-Fit Test For A Family Of Two Parameter Weibulls With Known Shape Using Minimum Distance Estimation Of Parameters, John S. Crown

Theses and Dissertations

This research is to produce a modified Anderson-Darling goodness of fit test for the Weibull distribution when the location parameter is found by minimum distance estimation, the shape parameter is assumed known, and the MLE is used for the scale parameter. The critical values for the Anderson-Darling test are generated via Monte Carlo simulation when both the Anderson-Darling and Cramer-Von Mises distance statistics are minimized. These critical values are then used for a power study. The Monte Carlo simulation used 5000 repetitions for sample sizes of 5,8,12,15,16,20 and 25 with the Weibull shape parameter of . 5(.5)4.0. The power study …

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The Boundary Element Method Applied To The Two Dimensional Stefan Moving Boundary Problem, Donald C. Vosika Mar 1991

The Boundary Element Method Applied To The Two Dimensional Stefan Moving Boundary Problem, Donald C. Vosika

Theses and Dissertations

This thesis considers problems for which the boundary is not known before the problem is solved and must be determined as part of the solution. We consider a time dependent problem which results in a moving boundary. We look at the heat conduction/diffusion equation in one and two spatial dimensions. We use Green's Theorem to yield a Volterra boundary integral equation which involves an unknown function on the moving boundary. We use the boundary element method to obtain a solution. Graphical results for the two dimensional problem are presented.

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Calculated Point Defect Properties Of The Intermetallic Compounds Nickel Titanium (Niti) And Iron Titanium (Feti), Russell T. Lutton Mar 1991

Calculated Point Defect Properties Of The Intermetallic Compounds Nickel Titanium (Niti) And Iron Titanium (Feti), Russell T. Lutton

Theses and Dissertations

Atomistic simulation with a modified version of the DYNAMO code was used to calculate the point defect properties of the intermetallic compounds nickel titanium and iron titanium. The calculated energies are believed to be experimentally accurate to within +/- 0.1 eV. Vacant Ni or Fe lattice sites were preferred and had energies of 6.356 eV for NiTi and 5.899 eV for FeTi. Removing a Ti atom resulted in a neighboring antisite defect caused by migration of a Ni or Fe atom into the vacant Ti site. These configurations had energies of 7.024 eV for NiTi and 6.336 eV for FeTi. …

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New Modified Anderson-Darling And Cramer-Von Mises Goodness-Of-Fit Tests For A Normal Distribution With Specified Parameters, Goksel Kahya Mar 1991

New Modified Anderson-Darling And Cramer-Von Mises Goodness-Of-Fit Tests For A Normal Distribution With Specified Parameters, Goksel Kahya

Theses and Dissertations

This thesis improves the powers of the Anderson-Darling and Cramer-von Mises goodness-of-fit tests using the mean rank and the median rank plotting positions. A Monte Carlo simulation of 5000 repetitions is used to generate the critical values from n =4 through n =80 for certain significance levels. An extensive power study is performed to compare the powers of the modified tests to the known tests for the uniform, the exponential, the double exponential, the lognormal, and the Weibull distributions. The power of the A-D tests modified by the median rank plotting and the mean rank plotting position are approximately 0.01% …

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Transfer Of 4gl Application From Ingres To Oracle, Adnan Altunisik Mar 1991

Transfer Of 4gl Application From Ingres To Oracle, Adnan Altunisik

Theses and Dissertations

This paper documents the transfer of 4GL applications from INGRES to ORACLE. As a result of a fast and conceptual change in computer languages, 4GLs were developed and evolved. These are programming support tools whose goal is, basically, to make the programs more efficient by reducing the number of instructions. Both ORACLE and INGRES database systems use 4GLs to develop applications. Their 4GL environments and their facilities for application development are investigated and explained in depth in this effort. The TWX application, which was originally implemented in INGRES by using its 4GL, is designed and reimplemented in ORACLE. This is …

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High Altitude Neutral Particle Transport Using The Monte Carlo Simulation Code Mcnp With Variable Density Atmosphere, David L. Monti Mar 1991

High Altitude Neutral Particle Transport Using The Monte Carlo Simulation Code Mcnp With Variable Density Atmosphere, David L. Monti

Theses and Dissertations

The Monte Carlo transport code, MCNP was modified for purposes of two dimensional neutron-photon transport modelling in a variable density atmosphere. Calculations were performed using cylindrical (r, z) geometry and a point isotropic neutron-photon source at an elevation of 40 kilometers. Neutron and photon fluence results were computed using ring detectors for field points at constant range versus source elevation angle and for field points at constant altitude versus radius. Comparisons between the modified and unmodified versions of MCNP showed a decrease in run time by a factor of two was possible. Only a fraction of the spatial cells previously …

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An Automated Red Player For The Theater Warfare Exercise, Karl W. Kabanek Mar 1991

An Automated Red Player For The Theater Warfare Exercise, Karl W. Kabanek

Theses and Dissertations

The Theater Warfare Exercise (TWX) is a two-sided, theater-level, decision-making exercise created, maintained and used by the personnel at the Air Force Wargaming Center. It is used to allow military officers to practice the decision-making process needed for the wartime employment of air power. An automated player was designed and a prototype implemented for the red (enemy) player using an expert system shell. The automated red player uses the TWX database that contains the data on the different units used in exercise. From the data the automated red player builds mission packages for the various types of missions required in …

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Optimal Iterative Task Scheduling For Parallel Simulations, Joann M. Sartor Mar 1991

Optimal Iterative Task Scheduling For Parallel Simulations, Joann M. Sartor

Theses and Dissertations

The ultimate purpose of this research is to reduce the time needed for execution of parallel computer simulations. In particular, the impact of task assignment strategies is determined for parallel VHDL circuit simulations. The classical scheduling problem, which assigns n precedence-constrained tasks to m processors is NP-complete in all but the simplest cases. The problem of assigning simulation tasks is further complicated by the iterative nature of computer simulations: each task is required to execute multiple times as the simulation executes. This investigation develops a polynomial-time algorithm (the level strategy) which provides optimal assignment for iterative systems with specific constraints. …

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A Computer Simulation Of Braitenberg Vehicles, Eric B. Werkowitz Mar 1991

A Computer Simulation Of Braitenberg Vehicles, Eric B. Werkowitz

Theses and Dissertations

In his treatise, Vehicles: Experiments in Synthetic Psychology, Valentino Braitenberg used simple, autonomous vehicle designs to illustrate the principles behind animal nervous system organization and operation. The goal of this effort was to produce a computer program to allow a researcher to experiment with these concepts and to analyze their performance using methods employed by experimental psychologists. The resulting program allows the user to design vehicles that respond to changes in their environments and that have the ability to adapt their behavior, using a learning algorithm developed by Teuvo Kohonen. The vehicle designer is free to select sensor attributes, …

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A Study Of The Liquid-Solid Interface During Rapid Resolidification Of Cooper-Titanium Using Molecular Dynamics, Craig L. Loisel Mar 1991

A Study Of The Liquid-Solid Interface During Rapid Resolidification Of Cooper-Titanium Using Molecular Dynamics, Craig L. Loisel

Theses and Dissertations

The behavior of the liquid-solid interface during resolidification of a condensed copper-titanium crystal is studied by atomistic simulation. A system of 1080 atoms (540 of each type) was simulated. The interface was created using monte carlo techniques and resolidification was performed by molecular dynamics. Resolidification was attempted at temperatures of 1200 K, 1100 K, 1000 K, 900 K, 818 K and 773 K. The liquid-solid interface was found to move only at 773 K, resulting in a chemically disordered crystal. The interface velocity observed in the simulation is 6.6 m/s which agrees well with the theoretical value of 5.5 m/ …

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An Assessment Of The Accuracy Of Semi-Empirical Quantum Chemistry Calculations Of The Mechanical Properties Of Polymers, James R. Shoemaker Mar 1991

An Assessment Of The Accuracy Of Semi-Empirical Quantum Chemistry Calculations Of The Mechanical Properties Of Polymers, James R. Shoemaker

Theses and Dissertations

The ultimate mechanical properties of polymers, assuming perfect morphology, will be limited by the mechanical properties of a single, ideal polymer chain. Previous calculations of polymer chain moduli using semi- empirical (SE) quantum chemistry methods have resulted in modulus values much higher than experimentally measured. This study investigated the error in the calculated inherent to the method of calculation by comparing SE results for C-C bond potentials in two well characterized polymers, polyethylene and polydiacetylene. It was found that the SE calculation systematically overpredicted bond stiffness in these polymers by approximately 25% to 30%. This is the upper limit on …

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A Network Flow And Goal Programming Approach To Modeling The Impact Of Pre-Accession Training To The Trained Personnel Requirements Process, William J. Beveridge Mar 1991

A Network Flow And Goal Programming Approach To Modeling The Impact Of Pre-Accession Training To The Trained Personnel Requirements Process, William J. Beveridge

Theses and Dissertations

HQ ATC was tasked to analyze the impact of pre-accession training to the Trained Personnel Required (TPR) and training production process. Pre- accession training is a policy of providing contracted initial skills training to enlistees prior to entering basic military training. The purpose of this study was to develop a method to model the impact of pre-accession training. A network modeling and goal programming approach was used. Comparisons between the current training policy and a pre-accession training policy were made. Sensitivity was conducted on the impact of a balk rate on the new policy. The balk rate is the percent …

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Three Degrees Of Freedom Compliant Motion Control For Robotic Aircraft Refueling, Clayton M. Andersen Dec 1990

Three Degrees Of Freedom Compliant Motion Control For Robotic Aircraft Refueling, Clayton M. Andersen

Theses and Dissertations

The Air Force Institute of Technology (AFIT) supports on-going research in application of robotic technology to enhance assembly tasks. As a testbed, AFIT supports the ground-based aerial refueling project, with an emphasis on visual servoing techniques and compliant motion control. This thesis focuses on compliant motion control. Previous research developed the testing environment, which includes a PUMA-560 industrial manipulator, and a half scale mock-up of an aerial refueling system. This effort corrected and expanded the existing two degree of freedom (DOF) compliant controller to three DOF. Three DOF compliance was demonstrated by inserting the refueling nozzle into the receiver port. …

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An Evolution Operator Solution For A Nonlinear Beam Equation, Carl E. Crockett Dec 1990

An Evolution Operator Solution For A Nonlinear Beam Equation, Carl E. Crockett

Theses and Dissertations

A nonlinear partial differential equation, motivated by the transverse vibration of a beam, is shown to have a unique solution. The existence theory, which is in the setting of semigroups and evolution operators, is a composite and synthesis of theorems of Kato. The formulation of the problem and the verification that the formulation leads to a solution are new. The introductory chapter provides background on the topic generally. Chapter 2 provides detailed formulations for the constant coefficient case. Chapter 3 describes nonautonomous cases. The general theorem is presented here. In Chapter 4, a more general case is considered. Namely, Kelvin …

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A Computer Model Of A Co2 Oscillator-Amplifier System, William F. Anderson Dec 1990

A Computer Model Of A Co2 Oscillator-Amplifier System, William F. Anderson

Theses and Dissertations

An existing CO2 laser amplifier simulation model developed for use on IBM-compatible personal computers has been improved through the redesign and addition of supplemental procedures from several models. The models and selected procedures which form the basis of the improved model are described. One procedure calculates the pumping rates of CO2 and N2 through calculation of the Boltzmann equation. Another procedure calculates the average vibrational temperatures of C2's vibrational modes. A third procedure replaces the Runge- Kutta integrator used in the original model with a faster, more accurate Adams- Bashforth-Moulton predictor-corrector integrator.

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Analysis Of Periodic Orbits About The Martian Moons By Continuation Techniques, Frank Luria Dec 1990

Analysis Of Periodic Orbits About The Martian Moons By Continuation Techniques, Frank Luria

Theses and Dissertations

From a few known periodic orbits of Phobos and Deimos, continuation techniques were used to find entire families of stable orbits. These techniques involved varying a parameter, the Hamiltonian, of the system and analyzing how the orbital behavior changed with the parameter. Floquet multipliers, for stability analysis, were also computed. AUTO86, a continuation/bifurcation software package, was used in this study. Artificial energy dissipation had to be added to the conservative Hamiltonian system to enable use of AUTO.

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