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In this dissertation the solutions of the dynamics and real-time optimal control of magnetic attitude control and formation flying systems are presented. In magnetic attitude control, magnetic actuators for the time-optimal rest-to-rest maneuver with a pseudospectral algorithm are examined. The time-optimal magnetic control is bang-bang and the optimal slew time is about 232.7 seconds. The start time occurs when the maneuver is symmetric about the maximum field strength. For real-time computations, all the tested samples converge to optimal solutions or feasible solutions. We find the average computation time is about 0.45 seconds with the warm start and 19 seconds with the cold start, which is a great potential for real-time computations. Three-axis magnetic attitude stabilization is achieved by using a pseudospectral control law via ...
Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry has been widely applied in the study of large biomolecules due to its capability for producing large intact molecular ions of biomolecules, its high sensitivity, and its ability to analyze mixtures in the presence of biological impurities. In this thesis, a linear time-of-flight (TOF) mass spectrometer with an extended mass range and high ion transmission efficiency, was employed for the separation and detection of large biomolecular ions produced by the MALDI technique. Using this methodology, DNA samples up to over 600 bp could be detected and mass analyzed. The speed and accuracy of MALDI TOF MS make it a potential alternative to gel electrophoresis for the analysis of biomolecules, such as DNA and proteins. MALDI using an ion trap/reflectron time-of-flight mass s...
This study investigates the association between bankruptcy risk and corporate governance in the United States and is presented in the form of three separate but related papers. The first paper is presented in Chapter 2. In this paper, we begin by evaluating five key bankruptcy models from the literature using an up-to-date data set and econometric methods. Early models of bankruptcy prediction employed financial ratios drawn from pre-bankruptcy financial statements and performed well both in-sample and out-of-sample. Since then there has been an ongoing effort in the literature to develop models with even greater predictive performance. A significant innovation in the literature was the introduction into bankruptcy prediction models of capital market data such as excess stock returns and stock return volatility, along with the ap...
A class of turbo-like codes with a crossover component, termed crossover product accumulate (CPA) codes is proposed. This structure is a serial concatenation of a crossover parallel concatenated code and an accumulator through an interleaver. A detailed iterative decoding scheme for CPA codes is described. Simulations show that different crossover depth makes CPA codes have different convergence in bit error rate (BER) performance, and a proper crossover structure produces faster convergence.
We conduct the multifractal analysis of the level sets of the asymptotic behavior of almost additive continuous potentials $(\phi_n)_{n=1}^\infty$ on a topologically mixing subshift of finite type $X$ endowed itself with a metric associated with such a potential. We work without additional regularity assumption other than continuity. Our approach differs from those used previously to deal with this question under stronger assumptions on the potentials. As a consequence, it provides a new description of the structure of the spectrum in terms of {\it weak} concavity. Also, the lower bound for the spectrum is obtained as a consequence of the study sets of points at which the asymptotic behavior of $\phi_n(x)$ is localized, i.e. depends on the point $x$ rather than being equal to a constant. Specifically, we compute the Hausdorff dimensi...
Submitted to International Environmental Conference, April 22-25, 2001, Charlotte, North Carolina.
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