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Full-Text Articles in Engineering
Linear And Nonlinear Adaptive Attitude Control Of Asteroid-Orbiting Spacecraft Using State Feedback And Output Feedback, Nicholas Moya
Linear And Nonlinear Adaptive Attitude Control Of Asteroid-Orbiting Spacecraft Using State Feedback And Output Feedback, Nicholas Moya
UNLV Theses, Dissertations, Professional Papers, and Capstones
This thesis presents the derivation of both a linear and nonlinear adaptive control law for the attitude states of a spacecraft in orbit around rotating asteroids. The asteroid is assumed to be irregularly shaped and in an elliptical orbit around the sun. The linearized, time-varying spacecraft model will assume to include unknown parameters and will have external disturbances present. The objective is to control the roll, pitch, and yaw angle trajectories of the spacecraft such that they track desired reference trajectories. To achieve this, the control law will be composed of (1) a feedback controller, sufficiently robust to disturbance such …
Nonlinear Adaptive Diffusion Models For Image Denoising, Ajay Kumar Mandava
Nonlinear Adaptive Diffusion Models For Image Denoising, Ajay Kumar Mandava
UNLV Theses, Dissertations, Professional Papers, and Capstones
Most of digital image applications demand on high image quality. Unfortunately, images often are degraded by noise during the formation, transmission, and recording processes. Hence, image denoising is an essential processing step preceding visual and automated analyses. Image denoising methods can reduce image contrast, create block or ring artifacts in the process of denoising. In this dissertation, we develop high performance non-linear diffusion based image denoising methods, capable to preserve edges and maintain high visual quality. This is attained by different approaches: First, a nonlinear diffusion is presented with robust M-estimators as diffusivity functions. Secondly, the knowledge of textons derived …
Adaptive Local And Global Synchronization And Phase Control Of Inferior Olive Neurons (Ions), Srujan Kumar Chalike
Adaptive Local And Global Synchronization And Phase Control Of Inferior Olive Neurons (Ions), Srujan Kumar Chalike
UNLV Theses, Dissertations, Professional Papers, and Capstones
Clusters of inferior olive neurons (IONs) in the olive-cerebellar system play an important role in providing synchronized motor control signals for the activation of large number of muscles. However, the dynamics of IONs are highly nonlinear and the system parameters are assumed to be unknowm. The IONs evolving from arbitrary initial conditions are not synchronized. However the application of IONs for control of BAUV's requires that IONs oscillate in unison. The objective is to design control laws such that the controlled ION tracks the trajectories of the reference ION. The two control laws are derived based on tuning functions adaptive …