Atmospheric boundary layers become stably stratified at night over land when the surface becomes colder than the air layer above. In stable nocturnal boundary layers (SNBL), turbulence becomes weak and intermittent, terrain-induced phenomena such as drainage currents or gravity-waves emerge and the surface heterogeneity is enhanced. Because of their complexity...
Crustal and upper mantle structures in the West Philippine Basin,
along 17-18°N, have been determined using explosions as sources and
ocean bottom seismometers to measure refracted compressional waves.
Seismic refraction profiles out to nearly 500 km were completed.
Shallow structure was measured using small shots, 1-240 lbs., and
the deeper...
When large disturbances occur in interconnected power systems, there exists the danger
that the power system states may leave an associated region of stability, if timely corrective action
is not taken. Open-loop remedial control actions such as field-forcing, line-tripping, switching of
series-capacitors, energizing braking resistors, etc., are helpful in reducing...
This thesis presents the design of various controllers for a highly maneuverable, high performance aircraft, namely the modified F-18. The aircraft was required to perform high angle-of-attack maneuvers, for which the aircraft behaves in as a highly nonlinear system. An adaptive PID controller was used to control the aircraft through...
The main focus of this work is on the problem of existence of nonlinear optimal controllers
realizable by artificial neural networks. Theoretical justification, currently
available for control applications of neural networks, is rather limited. For example,
it is unclear which neural architectures are capable of performing which control
tasks. This...
The present research investigates nonlinear barge motions through analyses of coupled multi-degree-of-freedom (MDOF) deterministic and stochastic models. Roll-Heave-Sway and other lower-ordered models are developed to predict the nonlinear motions and analyze the stability of a class of ship-to-shore cargo barges. The governing equations of motion contain coupled rigid body Roll-Heave-Sway...
This thesis contains three manuscripts addressing the application of stochastic processes to the analysis and solution of partial differential equations (PDEs) in mathematical physics.
In the first manuscript, one dimensional diffusion and Burgers equation are considered. The Fourier transform of the solution to each PDE is represented as the expected...
Extensive studies have been undertaken on the transient stability of large interconnected
power systems with flexible ac transmission systems (FACTS) devices installed.
Varieties of control methodologies have been proposed to stabilize the postfault system
which would otherwise eventually lose stability without a proper control. Generally speaking,
regular transient stability is...
This thesis presents a detailed seismotectonic investigation of the Himalayan region and the Tibetan plateau as part of project HiCLIMB to explore the state of stress and the kinematics of the world’s largest continental collision zone. Using full regional waveforms for moment tensor inversion, source parameters for 107 earthquakes were...
Functional control at the nanoscale forms the foundation of biological systems. These work at the cellular level by manipulating ions and molecules. Nanoscale devices that give functional control at this scale are also becoming an important component in diverse fields such as electronics, medicine, engineering, and manufacturing. Moreover, scientific advances...