Subgradient Optimization Methods in Integer Programming with an Application to a Radiation Therapy Problem

  • The thesis deals with the subgradient optimization methods which are serving to solve nonsmooth optimization problems. We are particularly concerned with solving large-scale integer programming problems using the methodology of Lagrangian relaxation and dualization. The goal is to employ the subgradient optimization techniques to solve large-scale optimization problems that originated from radiation therapy planning problem. In the thesis, different kinds of zigzagging phenomena which hamper the speed of the subgradient procedures have been investigated and identified. Moreover, we have established a new procedure which can completely eliminate the zigzagging phenomena of subgradient methods. Procedures used to construct both primal and dual solutions within the subgradient schemes have been also described. We applied the subgradient optimization methods to solve the problem of minimizing total treatment time of radiation therapy. The problem is NP-hard and thus far there exists no method for solving the problem to optimality. We present a new, efficient, and fast algorithm which combines exact and heuristic procedures to solve the problem.

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Metadaten
Verfasserangaben:Berhanu Guta
URN (Permalink):urn:nbn:de:bsz:386-kluedo-16224
Betreuer:Horst W. Hamacher
Dokumentart:Dissertation
Sprache der Veröffentlichung:Englisch
Jahr der Fertigstellung:2003
Jahr der Veröffentlichung:2003
Veröffentlichende Institution:Technische Universität Kaiserslautern
Titel verleihende Institution:Technische Universität Kaiserslautern
Datum der Annahme der Abschlussarbeit:17.09.2003
Datum der Publikation (Server):26.09.2003
Freies Schlagwort / Tag:Lagrangian relaxation ; integer programming ; multileaf collimator; radiation therapy ; subgradient
Fachbereiche / Organisatorische Einheiten:Fachbereich Mathematik
DDC-Sachgruppen:5 Naturwissenschaften und Mathematik / 51 Mathematik / 510 Mathematik
Lizenz (Deutsch):Standard gemäß KLUEDO-Leitlinien vor dem 27.05.2011

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