<p>GABLONSKY, JÖRG MAXIMILIAN XAVER. Modifications of the DIRECTAlgorithm. (Under the direction of Carl Timothy Kelley.)This work presents improvements of a global optimization method for boundconstraint problems along with theoretical results. These improvements arestrongly biased towards local search. The global optimization method known asDIRECT was modified specifically for small-dimensional problems with few globalminima. The motivation for our work comes from our theoretical results regarding thebehavior of DIRECT. Specifically, we explain how DIRECT clusters its search neara global minimizer. An additional influence is our explanation of DIRECT'sbehavior for both constant and linear functions. We further improved the effectiveness of both DIRECT, and our modification, bycombining them with another global optimization method known as ImplicitFiltering. In addition to these improvements the methods were also extended tohandle problems where the objective function is defined solely on an unknownsubset of the bounding box. We demonstrate the increased effectiveness androbustness of our modifications using optimization problems from the natural gastransmission industry, as well as commonly used test problems from theliterature. <P>
| Identifer | oai:union.ndltd.org:NCSU/oai:NCSU:etd-20010521-153035 |
| Date | 22 May 2001 |
| Creators | Gablonsky, Jörg M. |
| Contributors | C. T. Kelley, J. C. Dunn, P.A. Gremaud, M. Shearer |
| Publisher | NCSU |
| Source Sets | North Carolina State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://www.lib.ncsu.edu/theses/available/etd-20010521-153035 |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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