Engineering Commons^™

Nonlinear Observers For Human-In-The-Loop Control Systems, Samuel Kitchen Mckinley

Master's Theses - Daytona Beach

The development of models for a human-in-the-loop with hardware is an area of ongoing research. The ability to simulate a human-in-the-loop with hardware provides a platform for better understanding the dynamics of human and machine cognition. A human-in-the-loop model provides information that can be used to design more efficient human interfaces and smarter autonomous assistant controllers. This can make a complex task such as flying an aircraft safer and more accessible. This thesis explores different possibilities for human operator models to be modeled in the loop with a vehicle. A human is modeled as a linear state feedback controller in …

Investigation Of Magnetic Field Profile Effects In Hall Thrusters, Oren Kornberg

Master's Theses - Daytona Beach

The purpose of this study was to show the relationship of different magnetic field profiles to the acceleration region length of a Hall thruster. The general transport equations were simplified and solved using a one-dimensional analysis. Some of the model assumptions include quasineutrality, Maxwellian electrons, and negligible thruster wall effects. The solved equation kept magnetic field as an input to the model for the analysis. The magnetic field was altered by changing the shape through the thruster, while keeping the maximum point fixed, and by shifting the profile, while keeping the shape fixed. Results indicate a strong correlation between the …

Dynamics Of Nonlinear Diffusion Processes, Dustin A. Sipka

Master's Theses - Daytona Beach

The purpose of this thesis is to analyze nonlinear diffusion processes. In particular, some of the results arrived at by Newman and Sagan in their 1981 paper "Galactic Civilizations: Population Dynamics and Interstellar Diffusion," will be reproduced by different means. First, a thorough analysis of the linear diffusion equation will be performed in order to test a numerical algorithm that can solve the nonlinear diffusion equation and look at the processes of interest with sufficient accuracy. Once the algorithm is tested and shows good resolution it is used to solve the nonlinear equation. The post processing is then done to …

Planetary Wave Activity Observed In Polar Mesospheric Clouds, David A. Mackler

Master's Theses - Daytona Beach

In this paper, the Solar Backscatter UV spectrometer (SBUV) Polar Mesospheric Cloud (PMC) dataset was investigated for planetary wave activity following the earlier study by Merkel [2002]. To counter the sparse nature of the data, four separate methods of analysis are used in determining if planetary waves are present and how they effect PMC formation. The four methods are histograms (both in frequency of occurrence and mean albedo), periodograms using the Lomb-Scargle method, frequency-wavenumber analysis using a 2D Lomb-Scargle method from Wu et. al [1995], and a temporal (yearly) analysis of the 5, 6.5, and 10 day wave amplitudes. The …

A Full-Wave Investigation Of The Use Of A 'Cancellation Factor' In Gw-Airglow Interaction Studies, Yonghui Yu

Master's Theses - Daytona Beach

Atmospheric gravity waves (GWs) perturb minor species involved in the chemical reactions of airglow emissions in the mesopause region of the earth's atmosphere. The so-called 'Cancellation Factor' (CF) is defined as a transfer function relating the amplitude of airglow brightness fluctuation to the amplitude of GW-induced fluctuation in temperature [Swenson and Gardner, 1998]. This transfer factor can be used to determine GW fluxes and the forcing effects of GWs on the mean state through airglow observations, because GW fluxes are proportional to the square of GW amplitude.

Numerical models [Walterscheid et al., 1987; Schubert et al., 1991] have previously shown …

Effect Of Joystick Versus Control Yoke Use On Personal Computer (Pc) Flight Training: A Comparative Analysis, Gregory Alan Fontaine

Master's Theses - Daytona Beach

The purpose of this study was to provide a comparative performance analysis of a generic control yoke device and a generic joystick device. The comparison provided data needed for further evaluation of personal computer (PC) aircrew training device (ATD) potential. Both devices were used in support of the same PC flight simulation software program, and were evaluated using the experimental research method. Objective and subjective data were obtained during controlled testing, and subsequently analyzed using basic summation and t-test methods. The results tested the research hypothesis that there is no significant difference in personal computer ATD operator performance using a …

Data Reduction Procedure For An Experimental Method Of Measuring The Velocity-Coupled Response Function Of Solid Propellants, William H. Jarvis

Master's Theses - Daytona Beach

A computer program has been developed for calculation of the velocity-coupled response function of solid-propellants from experimentally measured pressure data. The proposed velocity-coupled response function measurement apparatus consists of an end-burner combustor where the propellant sample is oscillated in a direction normal to the flow in the presence of a standing acoustic wave within the combustion chamber. The pressure measurements are made at select points along the length of the chamber.

The data reduction program consists of a Runge-Kutta routine driven by a BFGS multivariable search routine. The Runge-Kutta routine determines the pressure distribution within the chamber of the proposed …