Thesis (doctoral)--Universität Karlsruhe, 1999.

Thesis (M.S.)--California Polytechnic State University, 2009. / Mode of access: Internet. Title from PDF title page; viewed on December 10, 2009. Major professor: Marni Goldenberg. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree [of] Master of Science in Agriculture." "December 2009." Includes bibliographical references (p. 105-113).

Thèse de doctorat : SCIENCES APPLIQUEES : Metz : 1994. / 1994METZ031S. 57 REF.

Thesis (Ph.D)--Aerospace Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Dr. Dimitri N. Mavris; Committee Member: Dr. Brian J. German; Committee Member: Dr. Daniel P. Schrage; Committee Member: Dr. Frederic Villeneuve; Committee Member: Dr. Michelle R. Kirby; Committee Member: Ms. Antje Lembcke. Part of the SMARTech Electronic Thesis and Dissertation Collection.

In 1955, Cassels proved a now celebrated theorem giving a search bound algorithm for determining whether a quadratic form has a nontrivial zero over the rationals. Since then, his work has been greatly generalized, but most of these newer techniques do not follow his original method of proof. In this thesis, we revisit his 1955 proof, modernize his tools and language, and use this machinery to prove more general theorems regarding height bounds for the common zeros of a system of polynomials in terms of the heights of those polynomials. We then use these theorems to give a short proof of a more general (albeit, known) version of Cassels' Theorem and give some weaker results concerning the rational points of a cubic or a pair of quadratics. / text

In this thesis, We study the driven Morse system in a strong time-periodic field. We are interested in the quasi-bound states, which live in the driven system with limit life-times, with an increasing field strength in a low frequency region. We found those states by using Floquet theory, and the exterior complex scaling method (ECCS), which widely use in the resonance system. Choosing the Morse potential with supports 3 bound states, we found that as we increase the time-periodic external field, the number of the quasi-bound states decrease to 2. The distributions of the quasi-bound states which represented by the Husimi distribution were also studied, and compared with the Poincaré surface of section plots of the system. / text

ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / A broadband passive direction finding system utilizing Luneburg lens has been investigated. With the simulated power level distribution at the detectors mounted on a Luneburg lens, both Cramér-Rao bound (CRB) and the root mean square error (RMS) based on the Correlation Algorithm (CA) for the direction of arrival (DoA) estimation have been derived and calculated. Guidelines on how to design the Luneburg lens detecting system have been studied. Finally, as a proof-of-concept demonstration, the DoA performance of a Luneburg lens fabricated using the polymer jetting technology with five detectors 10° equally spaced to receive the azimuth signal from -20° to 20° is demonstrated.

This dissertation consists of three essays on income risk and aggregate demand over the business cycle, each addressing an aspect of the Great Recession. The first chapter reframes the standard liquidity trap model to illustrate the costly feedback loop between idiosyncratic risk and aggregate demand. I first show that a liquidity trap can result from excess demand for precautionary savings in times of high uncertainty. Second, I show that the output and welfare costs of the ensuing recession depend crucially on how the drop in demand for output is translated into a reduction in demand for labor. Increased unemployment risk compounds the original rise in idiosyncratic productivity risk and reinforces precautionary motives, deepening the recession. Third, I show that increasing social insurance can raise output and welfare at the zero bound. I decompose these effects to distinguish the component unique to the liquidity trap environment and show that social insurance is most effective at the zero bound when it targets the type of idiosyncratic risk households face, which in turns depends on the labor market adjustment mechanism. The second paper offers a novel model of the connection between the consumer credit and home mortgage markets through an individual’s credit history. This paper introduces a novel justification for the home mortgage interest deduction. In an economy with both housing assets and consumer credit, the mortgage interest deduction is modeled as a subsidy for the accumulation of collateralizable assets by households who have maintained good credit. As such, the subsidy loosens participation constraints and facilitates risk-sharing. Empirical evidence and a calibration exercise reveal that the subsidy has a sizable impact on the availability of credit. The third paper assesses the role of policy uncertainty in the Great Recession. The Great Recession features substantial geographic variation in employment losses, a fact that is often presented as a challenge to uncertainty-based models of the downturn. In this paper we show that there is a substantial correlation between the distribution of employment losses and the increases in local measures of both economic and policy uncertainty. This relationship is robust across a wide range of measures. / Economics

The research reported in this thesis considers the classical combinatorial optimization problem known as the Generalized Assignment Problem (GAP). Since the mid 1970's researchers have been developing solution approaches for this particular type of problem due to its importance both in practical and theoretical terms. Early attempts at solving GAP tended to use exact integer programming techniques such as Branch and Bound. Although these tended to be reasonably successful on small problem instances they struggle to cope with the increase in computational effort required to solve larger instances. The increase in available computing power during the 1980's and 1990's coincided with the development of some highly efficient heuristic approaches such as Tabu Search (TS), Genetic Algorithms (GA) and Simulated Annealing (SA). Heuristic approaches were subsequently developed that were able to obtain high quality solutions to larger and more complex instances of GAP. Most of these heuristic approaches were able to outperform highly sophisticated commercial mathematical programming software since the heuristics tend to be tailored to the problem and therefore exploit its structure. A new approach for solving GAP has been developed during this research that combines the exact Branch and Bound approach and the heuristic strategy of Tabu Search to produce a hybrid algorithm for solving GAP. This approach utilizes the mathematical programming software Xpress-MP as a Branch and Bound solver in order to solve sub-problems that are generated by the Tabu Search guiding heuristic. Tabu Search makes use of memory structures that record information about attributes of solutions visited during the search. This information is used to guide the search and in the case of the hybrid algorithm to generate sub problems to pass to the Branch and Bound solver. The new algorithm has been developed, imp lemented and tested on benchmark test problems that are extremely challenging and a comprehensive report and analysis of the experimentation is reported in this thesis.

This mixed-methods study examined the effectiveness of the Upward Bound TRIO program in preparing a low-income and first-generation population for the successful completion of high school and acceptance into postsecondary institutions of higher learning. Data collection methods for this study were comprised of teacher and student surveys and program director interviews. A comparison of two Upward Bound programs was conducted in the southern regions of Virginia and Georgia. The results were analyzed and queried as to whether the current program objectives were effective in meeting the needs of low-income, first-generation students and whether the program provided the necessary academic and technological skillsets and support needed to gain employment in knowledge capital economy. The goal of Upward Bound is to increase the rate at which participants complete secondary education and enroll in institutions of higher learning. The significance of this study is that it offers insight on the necessary support structures needed to assist low-income and first-generation students. The study was an in depth analysis of the Upward Bound TRIO program’s current objectives in meeting the needs of the 21st century learner. Information gathered from the literary sources as well as other sources provides additional insight for the researcher on program practice, evaluation, efficiency, and low-income first-generation students’ success.