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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
151

Computational Study of Mean-Risk Stochastic Programs

Cotton, Tanisha Green 03 October 2013 (has links)
Mean-risk stochastic programs model uncertainty by including risk measures in the objective function. This allows for modeling risk averseness for many problems in science and engineering. This dissertation addresses gaps in the literature on stochastic programs with mean-risk objectives. This includes a need for a computational study of the few available algorithms for this class of problems. The study was aimed at implementing and performing an empirical investigation of decomposition algorithms for stochastic linear programs with absolute semideviation (ASD) and quantile deviation (QDEV) as mean-risk measures. Specifically, the goals of the study were to analyze for specific instances how algorithms perform across different levels of risk, investigate the effect of using ASD and QDEV as risk measures, and understand when it is appropriate to use the risk-averse approach over the risk-neutral one. We derive two new subgradient based algorithms for the ASD and QDEV models, respectively. These algorithms are based on decomposing the stochastic program stage-wise and using a single (aggregated) cut in the master program to approximate the mean and deviation terms of the mean-risk objective function. We also consider a variant of each of the algorithms from the literature in which the mean-risk objective function is approximated by separate optimality cuts, one for the mean and one for the deviation term. These algorithms are implemented and applied to standard stochastic programming test instances to study their comparative performance. Both the aggregated cut and separate cut algorithms have comparable computational performance for ASD, while the separate cut algorithm outperforms its aggregate counterpart for QDEV. The computational study also reveals several insights on mean-risk stochastic linear programs. For example, the results show that for most standard test instances the risk-neutral approach is still appropriate. We show that this is the case due to the test instances having random variables with uniform marginal distributions. In contrast, when these distributions are changed to be non-uniform, the risk-averse approach is preferred. The results also show that the QDEV mean-risk measure has broader flexibility than ASD in modeling risk.
152

Exitonic condensation in bilayer systems

Su, Jung-Jung. January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.
153

Mathematical modeling of field driven mean curvature surfaces

Moulton, Derek E. January 2008 (has links)
Thesis (Ph.D.)--University of Delaware, 2008. / Principal faculty advisor: John A. Pelesko, Dept. of Mathematical Sciences. Includes bibliographical references.
154

Mean field and correlated descriptions of Bose-Einstein condensates /

Mahmud, Khan W. January 2004 (has links)
Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (p. 127-136).
155

Dynamics of Bose-Einstein condensates in optical lattices /

McKinney, Sarah. January 2004 (has links)
Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (p. 125-134).
156

Some results on the mean square formula for the riemann zeta-function /

Lau, Yuk-kam. January 1993 (has links)
Thesis (M. Phil.)--University of Hong Kong, 1994. / Includes bibliographical references (leaves 32-33).
157

Relativistic mean-field theory applied to the study of neutron star properties /

Diener, Jacobus Petrus Willem. January 2008 (has links)
Thesis (MSc)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.
158

Pattern formation in cellular automaton models characterisation, examples and analysis /

Dormann, Sabine. Unknown Date (has links) (PDF)
University, Diss., 2000--Osnabrück.
159

Die nukleare Zustandsgleichung in relativistischen Schwerionenstößen

Gaitanos, Theodoros. Unknown Date (has links)
Universiẗat, Diss., 2000--München.
160

Long time behavior of a spherical mean field model

Dahms, René Unknown Date (has links) (PDF)
Techn. University, Diss., 2002--Berlin.

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