Exact Feedback Linearization of Systems with State-Space Modulation and Demodulation

The control theory of nonlinear systems has been receiving increasing attention in recent years, both for its technical importance as well as for its impact in various fields of application. In several key areas, such as aerospace, chemical and petrochemical industries, bioengineering, and robotics, a new practical application for this tool appears every day. System nonlinearity is characterized when at least one component or subsystem is nonlinear. Classical methods used in the study of linear systems, particularly superposition, are not usually applied to the nonlinear systems. It is necessary to use other methods to study the control of these systems. For a wide class of nonlinear systems, a rather important structural feature comes from the strong nonlinearity appearing as coupling between spectrally decoupled parts of the system. Even in the case of low frequencies, where lumped models can still be employed the nonlinear coupling between parts of the system requires specific treatment, using advanced mathematical tools. In this context, an alternative, frequency domain approach is pursued here. In the rest of this work, a specific system form of linearly decoupled but nonlinearly coupled subsystems is examined. The mathematical toolbox of the Hilbert transform is appropriately introduced for obtaining two low-pass subsystems that form an equivalent description of the essential overall system dynamics. The nonlinear coupled dynamics is investigated systematically by partitioning the coupled system state vector in such a way as to fully exploit the low-pass and the band-pass intrinsic features of free dynamics. In particular, by employing the Hilbert Transform, a low-pass equivalent system is derived. Then, a typical case is investigated thoroughly by means of numerical simulation of the original coupled low and band-pass, real-state-variable system and the low-pass-equivalent, complex-state-variable derived one. The nonlinear model equations considered here pave the way for a systematic investigation of nonlinear feedback control options designed to operate mechatronic transducers in energy harvesting, sensing or actuation modes

Maritime Advanced Geospatial Intelligence Craft for Oil Spill Response: Selected Resources and Annotations

This selection of resources highlights the utility of Unmanned Surface Vehicles (USV) for use in marine spill response. Each entry is followed by a brief summary and evaluation of the source (i.e., the annotation). Most annotations will define the scope of the source, list significant cross references, and identify relevant USV capabilities. There is no attempt to provide actual hypotheses, data, or graphics, especially concerning cited articles published in refereed journals. The purpose of the annotation is to inform the reader of the relevance, accuracy, and quality of the sources cited. Relevance relates to the citation’s presentation of capabilities that improve marine spill response operations. Significant interest involves the use of sensors that characterize the environment to support oil spill cleanup operations. The diversity of resources is especially relevant since no two oil spills are the same owing to the variation in oil types, locations, and weather conditions. The development of USVs for oil spill monitoring, cleanup, and science reduces some of the dependence on expensive ship time

Maritime Advanced Geospatial Intelligence Craft for Oil Spill Response: Selected Resources and Annotations

This selection of resources highlights the utility of Unmanned Surface Vehicles (USV) for use in marine spill response. Each entry is followed by a brief summary and evaluation of the source (i.e., the annotation). Most annotations will define the scope of the source, list significant cross references, and identify relevant USV capabilities. There is no attempt to provide actual hypotheses, data, or graphics, especially concerning cited articles published in refereed journals. The purpose of the annotation is to inform the reader of the relevance, accuracy, and quality of the sources cited. Relevance relates to the citation’s presentation of capabilities that improve marine spill response operations. Significant interest involves the use of sensors that characterize the environment to support oil spill cleanup operations. The diversity of resources is especially relevant since no two oil spills are the same owing to the variation in oil types, locations, and weather conditions. The development of USVs for oil spill monitoring, cleanup, and science reduces some of the dependence on expensive ship time

OMAE2011-49827 STATION KEEPING ADAPTIVE CONTROL OF A BOAT WITH TWIN GASOLINE OUTBOARD MOTORS: SYNTHESIS, SIMULATION, AND SEA-TRIALS

ABSTRACT There are increasingly more areas in which automatic station keeping technology can be of great benefit for small boat operators. This trend stems from technological advances that allow for smaller and more portable instrumentation and gear, bringing down the necessary size of vessels, which ultimately reduces cost. However, smaller vessels find themselves more adversely affected by sea conditions and have limited thrusting capabilities. Currently a skilled captain is needed on these small vessels to hold position over the area of interest in the presence of wind, wave, and current disturbances. Implementation of an automatic station keeping controller would free the captain from constantly monitoring the navigational instruments, to more closely supervise onboard operations and keep watch for other vessels in the area. Station keeping technology is currently being perused by Florida Atlantic University to enhance the ability of its 33ft boat to make oceanographic measurements in the Gulf Stream pertinent to its ocean energy projects. Such ocean energy projects require water velocity and temperature measurements at specific locations as part of the efforts for assessment of the hydrokinetic and ocean thermal resource. This technology is also a pivotal part of the sea basing goal currently being pursued by the Navy, which would allow vessels to stay in close but acceptable proximity to one another. The ability to hold position over a desired location can also have many additional uses such as for fishing, conducting surveys, deploying instruments, and transferring cargo or personnel. This text presents a novel approach for doing station keeping, as thus far a system for station keeping on small vessels using only tied twin outboard motors has not been developed and applied to an ocean going vessel by industry or academia. These controllers have been developed using multiple fixed-gain and adaptive control algorithms. Using a custom sensor and control system mounted onboard the test vessel; navigational measurements are used to adjust the throttles and engine angle using these developed algorithms. The performance of each of these controllers has been quantified using both numerical simulations and at sea testing. Using the results from these tests, initial comparisons have been made that show the advantages gained by using adaptive control algorithms instead of fixed-gain control

A Maritime Advanced Geospatial Intelligence Craft for Oil Spill Response: White Paper

In line with current research thrusts on unmanned systems, the University of New Orleans has formed a collaborative team from industry, academia, and government (e.g., Department of Homeland Security). UNO’s intent is to work with organizations such as the Bureau of Safety and Environmental Enforcement (BSEE) to experiment and demonstrate the potential offered by Unmanned Surface Vessels within the Gulf of Mexico

A Maritime Advanced Geospatial Intelligence Craft for Oil Spill Response: White Paper

In line with current research thrusts on unmanned systems, the University of New Orleans has formed a collaborative team from industry, academia, and government (e.g., Department of Homeland Security). UNO’s intent is to work with organizations such as the Bureau of Safety and Environmental Enforcement (BSEE) to experiment and demonstrate the potential offered by Unmanned Surface Vessels within the Gulf of Mexico

Prognostic significance of HER3 and HER4 protein expression in colorectal adenocarcinomas

BACKGROUND: Colorectal cancer remains a major cause of cancer mortality in the Western world. A limited number of studies has been conducted in respect of Her-3 and Her-4 expression and their correlation with clinical parameters and prognosis in colorectal carcinomas . In this study we sought to determine the pattern and the prognostic significance of HER-3 and HER-4 in colorectal adenocarcinoma. METHODS: We studied HER-3 and HER-4 protein expression in106 paraffin embedded specimens of primary colorectal tumors using immunohistochemistry. The pattern and protein expression levels of HER-3 and HER-4 were correlated with several clinical and pathological parameters. RESULTS: HER-3 staining displayed membranous and cytoplasmic expression pattern in 18 (17%) and 30 samples (28,3%), respectively. HER-4 membranous and cytoplasmic expression was found in 20 (18,9%) and 32 samples (30,2%), respectively. Specimens regarded as positive for HER-3 cytoplasmic expression were associated with moderate tumor grade (p = 0,032) and older median age (p = 0,010). Specimens regarded as positive for HER-4 membranous protein expression were associated with involved lymphnodes (p = 0,0003). Similar results were obtained when considering Her-3 and Her-4 protein expression irrespective of their cellular localization. There was no correlation between the expression of HER-3 and HER-4 and patients outcome. CONCLUSION: HER-4 membranous protein expression was found to predict for lymph nodes positivity in this cohort of patients with colorectal cancer.HER-4 expression status may identify tumors with aggressive biological behavior and increased metastatic potential

Mathematical Formulation of Fusion Energy Magnetohydrodynamics

Chapter 1 presents the basic principles of Controlled Thermonuclear Fusion, and the approaches to achieve nuclear fusion on Earth. Furthermore, the basic components of the Tokamak, the reactor which will house the fusion reaction, are analyzed. Finally, the chapter ends with a discussion on how the present thesis is related to the Controlled Thermonuclear Fusion. Chapter 2 introduces briefly the basic concepts of the Electromagnetic and Magnetohydrodynamic theories as well as MHD turbulence. Chapter 3 presents a first glance in OpenFOAM CFD library. Chapter 4 introduces the Orszag-Tang vortex flow, which is a benchmark test case for MHD numerical models. Also, the results obtained by the model developed in this thesis are presented and discussed. Chapter 5 describes an analytical solution method for the MHD natural convection in an internally heated horizontal shallow cavity. Also, a finite volume numerical model is presented for solving the aforementioned problem and properly validated. The results of the numerical model are compared with the analytical solutions for a range of Rayleigh and Hartmann numbers. Finally, conclusions based on this work are drawn and recommendations for future work are made